Note: Descriptions are shown in the official language in which they were submitted.
lQ983~3 `"
BACKGROUND AND SUMMARY OF THE DISCLOSURE
This invention relates generally to a single point fuel injection
system and, more particularly, to the mechanical,electromechanical and
electronic portions of a fuel management system for delivering a charge of
fuel to a specified opening intake valve of the engine fro~ a single
point in a throttle body.
The majority of automobiles being built today have fuel systems
which are either controlled by means of a carburetor or a multipoint fuel
injection system. While the multipoint fuel injection system has been
found to be an improvement over the carburetor, it too has problems which
require solution. The system being described herein is calculated to
combine the advantages of both systems and either solve or ameliorate the
inherent problems of the two systems.
In the case of a carburetor, while it has an advantage of low cost
and low operating fuel pressure, there are many undesirable characteristics
inherent to the use of a carburetor. For example, the operation of a
carburetor requires a continuous flow of fuel, the quantity of fuel being
determined on the position of the throttle. It has been found that the
fuel is not properly atomized and entrained in the air flow through the
throat of the carburetor. Without proper atomization, the fuel distribution
to the various cylinders is uneven thereby causing a rich or lean mixture
from one cylinder to another. This situation increases the objectionable
emissions from the particular cylinder which is too rich or too lean relative
to stoichiometric. Also, relative to a fuel injection system, the
carbureted system is inherently inaccurate in its fuel control whereby all
of the cylinders may be operating at a point different from optimum.
Further, carbureted systems are typically operated in an open
loop mode of operation. Wi~h this type of operation, the output of the
engine exhaust system is not sensed to determine the quality of combustion
which is occuring in the engine. Under these circumstances, the optimum
airJfuel ratio is not achieved and h;gher emission levels are again
experienced.
10~83~3
The shortcomings of a carbureted system have been somewhat
eliminated by certain multipoint fuel injection systems on the market.
W~th a multipoint fuel injection system, the fuel management is provided
w~th a rather precise control of the fuel being fed to the engine which
results in improved driveability without unwanted surges, lower emission
levels, convenient changes of the calibration of the system, and the
system may be operated in a closed loop mode of operation.
However, multipoint fuel injection systems do have certain
undesirable characteristics which, if overcome, would increase the use
of injected fuel management systems. For example, a typical multipoint
fuel injection system involves a higher cost in the initial installation
due to the sophisticated injectors being utilized and the inherent high
cost of the control electronics. Also, due to the requirement of a precise
fuel pulse being fed to each cylinder, the fuel distribution between
cylinders may vary due to the fact that the injectors are not matched, one
to the other. As is the case with a carburetor, unless the fuel is highly
atomized and rapidly carried to the appropriate cylinder immediately upon
injection of fue1 into the air stream, wall wetting is experienced. In
the situation where the wetting of the walls with fuel is occurring, fuel
is unevenly distributed to the cylinders and results in an uneven air/fuel
ratio from cylinder to cylinder. Also, with wall wetting, the fuel charge
being fed to the same cylinder from one cycle to the next may vary depending
on the amount of fuel on the walls of the manifold. Upon injection of a
fuel pulse which wets the walls of the manifold, the cylinder will receive
a leaner air/fuel ratio charge than required. Subsequently, the fuel on
the walls of the manifold will be entrained into the air stream to create
a rich air/fuel mixture, which air/fuel mixture is not directly controlled
by the duration of the fuel injection pulse. This results in power surges
and deteriorates the driveability of the automobile.
With a multipoint system, there are problems involved in the hot
starting of the automobile and hot fuel handling due to the fact that the
:l~ra83~3
injectors are positioned very close to the high heat areas of the engine,
as are the fuel lines feeding the injectors. This creates vaporization
of the fuel resulting in a low quantity of fuel being injected per pulse
to create a lean alr/fuel ratio. Further, the multipoint fuel injection
system requires a high pressure fuel system with the inherent sealing
problems and the cost of a high pressure pump.
With a multipoint fuel injection system, it is seen that an
injector is provided for each cylinder of the engine thereby requiring a
wholly self-contained injector at each cylinder. Further, the system
requires a pressure regulator which is separate from the injectors and a
plurality of fuel atomizers, one for each injector being utilized in the
system. It is obviously desirable to integrate all of the various parts
associated with a multipoint fuel injection system into a single unit
having a single housing. This reduces the cost of the system and also
reduces the possibility of malfunction.
Brief Description of the Disclosure
The system disclosed herein is calculated to combine the desirable
features of both the carburetor and multipoint fuel injection systems while
eliminating the problem areas of both systems to the extent possible.
The fuel management system disclosed herein takes advantage of the
manifold design inherent in automotive engines being produced today. In a
carbureted system, the manifold is designed such that the volume of air
between the point of introduction of a fuel charge and the intake valve
is equal for all cylinders to maintain a substantially equal distribution
of air fuel to each cylinder. Also, in carbureted systems presently being
utilized, an eight cylinder engine has the intake manifold devised in a
dual plane whereby four of the cylinders are fed from a first throat of
the carburetor and the remaining four cylinders are fed from a second
throat. Further, in certain engines, the manifold volume described above
which exists between the point of introduction of a fuel charge into the
throttle body to the inlet valve for a particular cylinder is less than the
volume of that particular cylir,der. In one typical engine, the volume of
1~83~;~
air between the point of introduction of fuel at the
throat and the inlet valve is 33 cubic inches while the
volume of any one cylinder in the engine is 44 cubic
lnches. Uith this configuration, the volume of air
between the throttle throat and an opening intake valve,
assuming all the remaining valves are effectively closed
within that manifold plane, will be entirely moved into the
cylinder which is on the intake portion of the cycle, and
additional air will be introduced from atmosphere to make
up the remaining volume required to fill the cylinder.
When the next valve opens within that manifold
plane, the volume of air between the point of introduction
of fuel and the opening inlet valve will be moved into the
cylinder in its entirety and further make-up air will be
added. It has been found that a charge of fuel injected
at the proper time relative to the opening point of the
intake valve will be moved to a specific cylinder, and
the additional make-up air will be introduced to the
cylinder after the fuel charge has entered the cylinder.
In this way, all of the fuel of any particular injection
pulse will be moved into a cylinder, minimizing wall wetting
of the manifold and the system, except for the intake
portion of the engine cycle, wlll contain dry air until the
next time a pulse of fuel is in~ected into the fuel inta~e
portion of the system. Further, the fuel is injected at the
last possible moment to take advantage of the latest engine
characteristic information. Also, no heating is necessary
to evaporate fuel.
According to the present invention there is
provided an injector for controlling the flow of fuel from
a source of fuel to a means for entraining the fuel in a
source of air in accordance with a preselected air/fuel
cbr/ ~
lQ'a83~3
ratio. The injector of the present invention has a frame
member, valve means supported in the frame member including
means form$ng a valve seat and a valve head cooperating
therewith, the valve seat having formed therein a metering
orifice. Electromagnetic actuating means is provided for
the valve head supported by the frame member and includes
a generally C-shaped core. A coil is mounted on one leg of
the core and an armature iR supported by the frame member
ad~acent the open end of the core having an extension
thereof engaging the valve head. Means i8 provided for
adjusting the degree of travel of the armature and thus
the valve head. The in;ector is open to the environment
in which it is placed.
A specific embodiment of the invention includes a
throttle body having one or more throats formed therein,
the number of throats corresponding to the number of
manifold planes which exist in the intake manifold of
the engine. As in conventional, the air flowing through
the throats is controlled by a throttle plate mounted in
the throat, the opening of which is controlled by the
driver. There is also formed in the throttle body a cavity
which forms the fuel bowl for introducing fuel into the
throats of the throttle body. The control of fuel from
the fuel bowl to the throttle body throat is controlled by
a single fuel injector per throat,
--6--
~"~ cbrl, o
~ 83~3
the fuel injector being pulsed in accordance with a preselected timing
scheme by means of an electronic control unit.
The electronic control unit may be a modification of an electronic
control unit presently being sold by The Bendix Corporation and designated
ECU II-l or ECU II-lA and bear Bendix part numbers 1611188 to 1611191 and
an altitude compensated version bearing Bendix part number 1612079. The
modifications to this electronic control unit to meet the objects of the
present fuel management scheme will be described in more detail
below .
As stated above, it is very important that the fuel being intro-
duced to the throat of the throttle body for any given plane of manifolding
be extremely finely atomized to enable a rapid transporting of the fuel
charge to the particular inlet valve which is in the opening mode. In
this way, the probability is maximized that the any entire fuel charge is
introduced to the cylinder corresponding to the opening intake valve and
the probability is minimized that any fuel will remain in the manifold
after the valve closes.
In accordance with the concepts of the present invention, the
preferred form of injection assembly includes a fuel injector and sonic
nozzle, the injector introducing a pulse of fuel into the sonic nozzle,
the sonic nozzle being interposed between the fuel injector and the throttle
body throat. Air passages are provided for the sonic nozzle to enable air
to be introduced at the inlet end of the sonic nozzle in response to a
reduction of manifold pressure during the operation of the automo~ile engine.
The sonic nozzle has been devised to maintain the air flowing
through the sonic nozzle or venturi at sonic velocity throughout the
major portion of the engine operating range. It has been found that the
sonic velocity is maintained with the configuration of the sonic nozzle
disclosed herein down to 4 inches of mercury vacuum. However, even
without sonic velocities, it has been found that atomization of the
fuel is adequate to ensure movement of the fuel charge to the opening
inlet valve at approximately 1 inch of manifold vacuum. At certain
983~3
other operations of the engine, for example extremely low engine speeds
and wide open throttle conditions, certain modifications to the system may
be incorporated to ensure that sufficient atomization of the fuel occurs.
For example, screens or baffles may be introducted in the throat in the
path of the fuel charge, or the nozzle of the venturi cou1d be extended
further into the throat than the distance disclosed in the drawings
associated with this specification, or the venturi of the sonic nozzle
could be bent to redirect the fuel flow down into the manifold.
As will be seen from the detailed description of the system
r ~
d~sclosed herein, the throttle bodylmay include a fuel bowl and an upper
cover ~s attached thereto to form an enclosed space into which fuel is
introduced and the major portion of the mechanical and electromechanical
portion of the fuel management system is housed. ~he enclosed space is
adapted to house the fuel injectors and a pressure regulator, the pressure
regulator being one of two different types, either a bypass metering
type or an inlet metering type.
With respect to the inlet metering type, the diaphragm of the
pressure regulator, in conjunction with the volume of the fuel bowl between
the pressure regulator diaphragm and the bottom of the fuel bowl, acts as
an accumulator whereby fuel is pumped into the bowl under pressure during
the discharge portion of the pump cycle and fuel is not pumped into the bowl
during the intake portion of the pump cycle. During this intake portion
of the pump cycle, the fuel injectors are still being pulsed to cause fuel
to be introduced into the throttle body throat and, as will be seen, fuel
is also being returned to the tank for venting purposes. Accordingly,
the fuel supply within the bowl is being depleted, which depletion would
have a tendency to decease the pressure within the fuel bowl. However,
the biasing spring of the pressure regu7ator causes the diaphragm to move
downwardly and thereby compress the fuel and maintain a constant fuel
pressure during the intake stroke of the fuel pump.
As noted above, with either pressure regulator disclosed herein,
it has been found that any vaporization of the fuel in the fuel bowl is
easily vented by means of a vent tube formed within the throttle body.
1~83~3
The particular construction of the injector valve itself is devised to
be generally open, thereby permitting any fuel vaporization formed in the
area of the injector to float to the top of the fuel bowl in the form
of bubbles, the bubbles then being vented to the fuel tank. This
arrangement enhances the hot fuel handling properties of the system.
As to the general details of a preferred form of injector assembly,
the injector assembly is fabricated from a frame member which is adapted
to generally enclose and retain a ball valve assembly relative to the valve
orifice, and the frame also fixes the electromagnetic portion of the injector
valve relative to the ball valve assembly. The electromagnetic portion
of the injector includes a generally C-shaped ferrous core which is attached
to the frame member, one leg of the C-shaped core having a coil bobbin
concentric therewith. The open end of the C-shaped core is provided with
a generally flat armature interconnected with the ball valve assembly to
actuate the ball valve assembly, thereby controlling the flow through
the valve orifice.
The above-described assembly has been found to be extremely
simple to manufacture and reliable in operation, and, through its open
configuration, minimizes the prospects of vaporized fuel from being injected
into the sonic air stream associated with the sonic venturi.
As will be seenfrom a reading of the detailed description of
the fuel management system disclosed herein, the electronic control unit
will produce, for an eight cylinder engine, eight pulses per engine cycle.
Thus, the injectors will be pulsed 4 times per engine revolution, or
8 times per engine cycle. In this way, an injector will be pulsed
once for each opening of an intake valve on the intake portion of the cycle.
Through testing, it has been found that the ideal point for injecting fuel
into the sonic nozzle occurs at 15 before top dead center of each cylinder
as it sequentially goes hto the intake portion of the engine cycle.
By pulsing an injector at 15 before top dead center, and every 90
thereafter for an eight cylinder engine, the fuel distribution to each
cylinder is maintained within one air/fuel ratio of every other cylinder
1~8393
of the engine. Thus, the problems inherent in uneven air/fuel ratio
distribution from cylinder to cylinder are alleviated. The above noted
timing is a typical example, and the optimum tirning varies for different
engine and man~fold design.
As noted above, the pulse generating circuitry, characterized
an electronic control unit, is a standard electronic control unit produced
by The Bendix Corporation with slight modifications. The above-noted
standard electronic control unit is utilized in conjunction with a
multipoint injection system wherein the injectors are divided into two
groups of four injectors per group for an eight cylinder engine.
Accordingly, each bank of injectors are pulsed once per engine cycle and
the electronic control unit must produce one output pulse per engine
revolution. In this situation, the duration of the output pulse can be
extended by the electronic control unit to 360 or an entire engine
revolution. With the system of the present invention however, the
electronic control unit must produce 4 pulses per engine revolution.
Thus, the duration of each of the output pulses is limited to a maximum
of 90 of an engine revolution. It is felt that this is insufficient to
provide sufficient pulse duration latitude and thus fuel control.
Accordingly, the standard electronic control unit is modified
by calibrating the standard electronic control unit pulse or base pulse
duration by one half, in the preferred embodiment. It is to be understood
that division by other multiples could be utilized. The output pulse
of the electronic control unit is then fed to 3 modification circuit
which multiplies the injector pulse to provide the control for the
injector itself. In this way, the duration of the output pulse from
the electronic control unit can be up to one half or 180 of an engine
revolution.
The modified electronic control unit also includes a transient
decay function circuit which provides a transient decay for an acceleration
enrichment pulse which is added to the base pulse in the situation where
/ 6i
1~'a83~?3
acceleration enrichment is needed. The transient decay function circuit
provides a transient decay for the acceleration enrichment pulse in
response to a rate of change of throttle position.
OBJECTS AND BRIEF DESCRIPTION OF THE DRAWINGS
Accordingly, it is one object of the present invention to provide
an improved fuel management system for use in connection with an internal
combustion engine.
It is another object of the present invention to provide an
improved fuel injection system for use in connection with a single
point fuel management control system,
It is a further object of the present invention to provide a
fuel management control system which has improved fuel atomization
characteristics.
It is still a further object of the present invention to provide
an improved fuel management system incorporating the advantageous features
of both a carburetion system and a fuel injection system for an internal
combustion engine.
It is still another object of the present invention to provide
an improved fuel management system which minimizes the fuel distribution
differential between cylinders of a multicylinder internal combustion engine.
It is still a further object of the present invention to provide
an improved fuel management system which decreases the wall wetting
characteristics of previous fuel management systems.
It is still a further objeot of the present invention to provide
an improved management system which ameliorates the hot start problems
heretofore experienced in internal combustion engines.
It is still another object of the present invention to provide
improved hot fuel handling characteristics in a fuel management system
for an internal combustion engine.
It is a further object of the present invention to provide fuel
management system of the injector type which utilizes a low pressure fuel
system.
lQ~8393
Further objects, features and advantages of the system of the
present invention will be become readily apparent from a reading of the
following specification and a consideration of the attached drawings in which:
FIGURE 1 is a schematic diagram of an engine and fuel management
system incorporating cèrtain features of the present inventioni
FIGURE 2 is a diagrammetic representation of the intake manifold
of an eight cylinder engine wherein the manifold is divided into two
planes of four cylinders per plane;
FIGURE 3 is a schematic diagram illustrating one form of fuel
regulation for use in conjunction with the fuel management system of the
present invention;
FIGURE 4 is a schematic d;agram illustrating another form of fuel
pressure regulation which may be adaptable for use in conjunction with
the system of the present invention;
FIGURE S is a side view of a throttle body and fuel bowl cover
combination in which are incorporated the features of the present invention;
FIGURE 6 is a cross sectional view of FIGURE S taken along lines
6-6 thereof;
FIGURE 7 is a cross sectional view of ~GURE 6 taken along line
7-7 thereof with the fuel bowl cover added thereto, the figure particularly
illustrating the relationship of the fuel injector and sonic nozzle
associated with the system of the present invention;
FIGURE 8 is a cross sectional view of FIGURE 6 taken along line 8-8
thereof with the details of the intake metering pressure regulator added
thereto;
lQ~83~3
FIGURE 9 is a cross sectional view of a throttle body
incorporating the injector and sonic nozzle assembly of FIGURE 7 and a
modified pressure regulator of FIGURE 8, the pressure regulator being
the bypass metering type;
FIGURE 10 is a cross sectional enlarged view of the sonic
nozzle of FIGURE 6 and 9 illustrating the specific details of the nozzle;
FIGURE 11 is a plan view of a preferred form of fuel injector
utilized in conjunction with the present invention;
FIGURE 12 is a cross sectional view of the injector of FIGURE 11
taken along line 12-12 thereof;
FIGURE 13 is a side view of the injector of FIGURE 11 and
particularly illustrating the retainer for the ball valve assembly;
FIGURE 14 is a cross sectional view of a modified form of the
injector of FIGURE 12;
FIGURE 15 is a timing diagram illustrating the relationship of
the rise of the intake valves for four of the cylinders of an eight
cylinder engine relative to engine rotation and also correlating the
start of the injector pulse relative to top dead center;
FIGURE 16 is a diagram illustrating the effect of injection timing
on air/fuel ratio distribution from cylinder to cylinder for two engine
speeds;
FIGURE 17 is a diagram similar to that illustrated in FIGURE 16
but illustrating the effect of injection timing on distribution of the
air/fuel ratio from cylinder to cylinder for a modified manifold engine;
FIGURE 18 is a block diagram illustrating the overall scheme
for modifying a standard electronic control unit described above;
FIGURE 19 is a block diagram illustrating the details of a
modification to the circuit diagram of FIGURE 18;
~ Q~83~3
FIGURE 20 is a schematic diagram illustrating a
portion of the electronic details of the block diagram of
FIGURE 18;
FIGURE 21, which is on the same sheet as PIGURE
19, is a tlming diagram illustrating the relationsip of
certain signals generated in the clrcuit of FIGURE 20;
FIGURE 22 is a cchematic diagram illustrating the
remaining electronic details of the block diagram of FIGURE
18; and
FIGURE 23 is a schematic diagram illustrating the
details of the block diagram illustrated in FIGURE 19.
DETAILED D~SCRIPTION OF THE DRAWINGS
Referring now to the drawings and particularly
FIGURE 1 thereof, there is illustrated an internal combustion
engine 30, an electronic control unit 32 for the engine and
a fuel supply system 34, the control of the fuel supplied
the engine being accomplished by the electronic control unit
32. Specifically, the engine includes the normal components
such as an intake manifold 36, cylinder heads 38, 40 and
valve covers 42, 44 as is typical in an eight cylinder V-type
engine, For purposes of simplicity, the disclosure will be
couched in terms of a V-8 type engine, but it is to be under-
stood that ~he invention is equally applicable to engines
having differing numbers of cylinders, as for example, four
or six or twelve cylinders, ~owever, it is felt that four
cylinders per manifold plane is probably the maximum number
of cylinders that can be accomodated for a single injector
due to the number of pulses which must be generated by the
electronic control unit per engine revolution. For example,
in a V-6 engine, it has been found that the firing of the
cylinders of the V-6 engine are not regularly spaced in that
the engine fires at 90 , 240, 330 and 480, 570 and 720
Accordingly, a different scheme of sensin& cran~shaft position
-14-
cbr/J~
` 10~83~3
- would be provided for a V-6 engine.
The fuel system for the engine 30 is provided from
a tank 48, the fuel from the tank 48 being fed to a throttle
body 50 from a conduit 52 and a fuel pump 54. The return to
the tank is provided by means of a
cbr/ J ,o
lQ983~3
conduit 58, the return fuel being delivered through either of two
different types of pressure regulators as will be more fully explained
in conjunction with the description of FIGURES 3, 4, 8 and 9.
The air being fed to the engine for mixture with the fuel is
controlled by the operator through a throttle plate 60 positioned in
the throat of the throttle body 50. The air is suitably filtered by
means of an air filter assembly 62 as is conventional in internal
combustion engines.
A modified electronic control unit 64 is included in the system
of the present .nvention and the preferred form is of the speed density
type which requires an engine speed sensor providing an input RPM
signal (designated RPM) to the control unit 64 fed to the control unit 64
by means of a conductor 66. Also, the manifold absolute pressure of the
engine is also sensed to provide a MAP signal on an input conductor 68.
As is well known in the injection art, the combination of engine speed
and MAP signal, particularly a function of the product thereof, will
provide an indication of the mass air flow to the engine. It is this mass
air flow which determines the mass of the fuel which is to be fed to the
engine. This type of system is utilized in conjunction with an open loop
control system. However, in a closed loop system, the control unit 64 is
supplied with a signal from an oxygen sensor positioned, typically, in
the exhaust system for the engine. The oxygen sensor then provides an
indication to the control unit 64 whether the engine is operating at
stoichiometric or either in the lean or rich side of stoichiometric.
These concepts are familiar to those skilled in the fuel management art.
Referring now to FIGURE 2, there is illustrated in diagrammetic
form a two plane eight cylinder engine manifold 36 having an upper
manifold chamber 70 illus~rated in solid lines and a lower manifold
chamber 72 illustrated in dotted lines. As was stated above, it is
felt that the maximum number of cylinders per manifold plane which could
-16-
lQ~8393
be accommodated by the system of the present invention is four. However,
most passenger car engines built in the United States have a dual manifold
system for eight, V-6 and twelve cylinder engines and therefore the system
of the present invention is applicable to most engines provided in passenger
cars.
Referring particularly to the upper plane manifold chamber 70,
it is seen that the chamber 70 feeds fuel charges to cylinders 2, 3, 5 and
8 with the configuration shown. The fuel charge is supplied by a single
point injector scheme to be described hereinafter, the charge being
introduced to the manifold within the throat 78 of the throttle body 50
described in conjunction with FIGURE l; and the fuel charge for the
lower plane manifold 72 is supplied through a throat 80 of the throttle body 50. As was stated above, it has been faund that the system of the
present invention provides an extremely even flow of fuel charged
distribution from cylinder to cylinder when the effective manifold volume
between the point of introduction of the fuel charge to the manifold
and the intake valve is less than the volume of the particular cylinder
betng fed with fuel charge. Referring to manifold chamber 70, it will
be seen that the effective volume of manifold 70 relative to cylinder 2
between throat 78 and the intake valve for cylinder 2, designated with
reference numeral 84, is equal to the effective volume of the manifold
chamber 70 between the throat 78 and the intake valve for cylinder 3,
designated with reference numeral 86. The same condition exists for
cylinders ~ and 8 relative to the remaining cylinders in the plane
including manifold chamber 70. It will be seen that the manifold chamber
72 is another plane and is identically configured to manifold chamber 70
with the identical relationship of the chamber volume between throttle
body throat 80 and the particular cylinder valve which is in the opening
mode of operation, relative to the volume of the cylinder involYed.
10~8393
Referring now to FIGURE 3, there is illustrated a schematic
fluid diagram for a fuel feed system for the single point injector
system, and particularly illustrating a bypass metering form of fuel
pressure regulator. The fuel system includes the tank 48 and fuel 90
described in conjunction with FIGURE l. For the particular bypass
metering pressure regulator system disclosed, a fuel pump 92 is
submerged in the fuel 90 contained within the tank 48. The pump supplies
fuel from a fuel line 94 to a fuel bowl 96 shown in dotted lines and
it should be noted that an injector lO0 is submerged within the fuel in
the bowl 96. This fuel bowl 96 will be more particularly described in
conjunction with FIGURES 6, 7, 8 and 9. The fuel feed to the injector
is schematically illustrated in FIGURE 3 as conduits 102, 104.
In actuality, the conduits 102 and 104 do not exist, rather the
open injector 100 is simply submerged in the fuel contained within the
fuel bowl 96 Fuel is also fed to a regulator 108, the details of which
will be described in conjunction with the description of FIGURE 9.
In the schematic diagram of FIGURE 3, main fuel flow is
schematically illustrated as being fed to the regulator 108 by a conduit
llO, the conduit llO being illustrated purely for descriptive purposes.
Fuel also flows to the regulator lO~ in the form of vapor from the
injector or vapor formed within the fuel bowl 96 and this vaporized
flow to the regulator is schematically illustrated as fuel flowing
along line 11~. The regulator 108 controls the pressure within the fuel
bowl 96 in response to the fuel pressure within the fuel bowl 96. If
the pressure becomes excessive, the regulator 1~8 opens to permit fuel
to flow back to the tank 48 through a conduit 116. As pressure drops,
the regulator valve moves toward the closed position to create a
greater pressure drop across the regulator and thereby build up the
pressure within the fuel bowl 96. As pressure drops further, the
regulator will close to shut off fuel flow in conduit 116. ~Jith the
-18-
~Q~83~3
bypass system illustrated schematically in FIGURE 3, the pump 92 can be
a relatively low pressure pump to provide approximately 7 psi of fuel
pressure within fuel bowl 96.
Referring now to FIGURE 4, there is illustrated a modified form
of pressure regulator system of the inlet metering type which again is
utilized to feed fuel 90 contained within the tank 48 to the fuel bowl 96.
The system illustrated in FIGURE 4 includes a conduit 118 for feeding
fuel from the tank to a fuel pump 120, the pump 120 providing pressurized
fuel for introduction to the fuel bowl 96 through a conduit 122. As will
be seen from a description of FIGURE 8, the conduit 122 terminates
at an inlet valve in the fuel bowl 96 in an inlet valve
configuration which controls the flow of fuel at the inlet into the fuel
bowl 96. As pressure within the fuel bowl 96 drops, the regulator 124 opens
the inlet valve of the regulator 124 to permit additional fuel to flow
into the fuel bowl 96. As pressure builds up within the fuel bowl 96,
the regulator inlet valve moves toward the valve seat to create a
larger drop across the inlet valve of the regulator. When the pressure
reaches a preselected amount, the regulator valve closes to shut off
fuel flow to the fuel bowl 96.
As was the case with the system of FIGURE 3, an open type
injector 128 is provided wherein the fuel bowl forms the housing for the
injector and fuel is permitted to flow around the injector prior to
exiting through the injector valve. Accordingly, any fuel which is
vaporized in the area of the injector is free to float to the top of the
fuel bowl 96 and to the fuel return line, schematically illustrated as
line 132. A slight amount of fuel is permitted to flow out of the
regulator and back to the tank by means of a conduit 132 to permit the
vapor and a slight amount of fuel from the fuel bowl 96 to flow back
to the tank to permit proper purging of vapor from the fuel bowl 96.
_19_
10~83~3
The details and operation of the regulator of FIGURE 4 will be more
fully appreciated upon consideration of the discussion of the operation
of the regu1ator illustrated in FIGURE 8.
Referring now to FIGURE 5 and 6, there is illustrated the various
details of a throttle body assembly 140 incorporating the features of
the present invention. Particularly, the throttle body includes a
throttle body throat section 142, and a fuel supply section 144. It will
be noted that FIGURE 6 is taken along 6-6 of FIGURE 5 which thereby
eliminates a cover assembly 146 from the details of FIGURE 6. However,
this opens an interior portion of the fuel supply section 144.
Referring specifically to the throttle body throat section, it
is seen that a pair of throats 150, 152 are formed in the throttle body
corresponding to the throats 78, 80 described above in conjunction with
the description of FIGURE 2. The interior of the throats 150, 152 are
provided with a pair of throttle plates 154, 156 as is conventional.
The opening and closing of the throttle plates 154, 156 are controlled
by a throttle linkage 160 which include a pair of limiting adjustable
screws 162, 164. Thus, the opening of the throttle plates 154, 156 are
controlled simultaneously by the movement of linkage 160 and the closing
limit of throttle plates 154, 156 are limited by the position of threaded
screws 162, 164.
The air to the throats 150, 152 is suitably filtered by a
filter element as described above in conjunction with the description of
FIGURE 1, the filter assembly being attached to an upstanding rod 166.
The throats 152 correspond to the throats for an eight cyl;nder or
six cylinder engine w~th dual plane manifolds described above. Further, as
is noted above in the case of a four cylinder engine, the throttle body
would include exactly one half of the items described in conjunction
with the throttle throat section and to be described in conjunctiGn
with fuel supply section 144.
-2~-
lQ~83~3
Referring now to FIGURE 6, there is illustrated the details
of the fuel iniector system and a portion of the details of the regulator
system, the remaininy details to be better understood from a description
of FIGURES 7 and 8. Specifically~ the fuPlsupp~y section 144 inc;udes
the cover 146 enclosing the upper portion of a fuel bowl 168 acting as
a fuel accumulator, a sediment collector and a housing for the fuel
injectors and the pressure regulator. Thus, the fuel bowl 168 forms a
common housing for the major elements of the pulsed fuel injection
system.
Spe,ificall~, fuel is introduced by means of an inlet valve 172,
the fuel col1ecting in the bottom portion of the fuel bowl 168. The
fuel which is accumulated in the fuel bowl 168 is fed to the throttle
body throats 150,152 by means of a pair of injectors schematically
illustrated at ~74, 176. The injectors are energized alternately at
specific angles of engine rotation depending on the type of engine being
supplied. As stated above, the injector 174 is energized every lgO
of engine rotation, for example, 15 before top dead center for two
cylinders of a single plane, and the other injector 176 is pulsed at 15
before top dead center for the other two cylinders in the other single
plane at angles which are 90 apart from the injection pulses of
injector 174.
The injectors, as will be seen from a description of FIGURE 7,
are of the sonic nozzle type and require a source of filtered air at the
space between the outlet for the injectors 174, 176 and the inlet to
the sonic nozzles to be described. Accordingly, the source of filtered
air is fed to the injector by means of a cross feed manifold formed in
the throttle body adjacent the outlet to the injectors (not shown) from
a hole 180 drilled vertically in the throttle body. The hole 180
communicates with the interior of the filter 62 described in conjunction
with FIGURE l.
- lQq83~3
As will be seen from a description of FIGURE 8, a gasket 182
forms the diaphragm for the pressure regulator and a leak proof seal
between the throttle body fuel bowl 168 and the housing cover 146.
The cover 146 is fastened to the throttle body by means of a plurality
of ~asteners 184, the housing 146 being cut away around the area of
aperture 180 to preclude interference with the free flow of air into
aperture 180. The electrical connections to the injectors 174, 176
are provided by means of a pair of suitable electrically insulated and
hydraulically sealed through connectors 186, 188. The connector 186
is formed by means of a threaded rod fed through an aperture 190,
the rod being positioned within the aperture 190 by means of a pair of
electrical insulators which also act as hydraulic seals. The seals are
compressed between a pair of inboard lock nuts, the outer nuts being
the fasteners for connecting the electrical conductors.
Referring now to FIGURE 7, there is illustrated the specific
details of the injector 174 mentioned above. As is seen from FIGURE 7,
the injector is positioned within the fuel bowl 168, and submerged within
the fuel accumulated therein, the output nozzle of the injector being
positioned within an aperture Z00 formed in the throttle body between
the fuel bowl 168 and the throttle body throat 150. While the details
of the injectOr will be left for a description of FIGURES 11-14, the
injector generally includes a C-shaped ferrons core 202 which is energized
by a coil 204 wound around one leg thereof. The flux within the core 202
causes a generally flat armature (not shown) to move within a frame 206
and thereby open and close the communication of fuel between the interior
of the fuel bowl 168 and a cross-feed, air-supply manifold 210. The
cross-feed manifold 210 is in fluid communication with the aperture 180
vertically drilled into the throttle body. The pulse of fuel introduced
into manifold 210 will then enter the intake throat of a sonic venturi 214,
the venturinoezle communicating manifold 210 with the throat 150.
-22-
- l~q83~3
The specific details of the development of the surfaces of the
sonic nozzle will be described in conjunction with the description of
FIGURE 10. However, the outlet end 218 of the sonic nozzle is
positioned near the intake manifold of the engine and therefore is
subject to manifold absolute pressure. This reduced pressure will cause
air to be drawn through the aperture 180, described in conjunction with
FIGURE 6, into the manifold 210 and through the sonic nozzle 214 to
exit at the exit end of the sonic nozzle. The nozzle is such that a
shock wave is created in the divergent portion of the throat due to the
fact that the air is in excess of sonic speeds. Therefore, the fuel being
injected into the sonic nozzle will hit the shock wave and fine
atomization will take place due to the high air speed. It has been found
that extremely find atomization occurs down to one inch of manifold
vacuum and, with sonic nozzles being utilized in testing the system of
the present invention, it has been found that sonic speeds are maintained
down to four inches of vacuum.
In installing the sonic nozzle in injector, the nozzle and
injector are both inserted into the aperture 200 from the fuel bowl side,
the nozzle 214 being inserted first and the injector 174 being inserted
thereafter. The fit between the sonic noz~le 214 and the aperture 200,
is a press fit. A suitable 0-ring 220 is utilized on the injector to
preclude fuel leakage around those elements.
As was stated and as will be noted from the description of the
electronics associated with the system of the present invention, the
electronic control unit is of the speed density type and requires an
indication of the manifold absolute pressure signal. Accordingly, a
conduit 226 is associated with each throttle bore which communicates the
portion of the throat 150 nearest the manifold with the exterior of the
throat for connection to the manifold absolute pressure sensor. Conduits
226 are interconnected to provide an average MAP signal to the electronic
-23-
i~83~3
control unit. Conduit 228 is used to provide a ported vacuum signal
as is commonly required for spark timing and EGR control.
FIGURE 8 discloses the specific details of a preferred form of
pressure regulator 230 of the inlet metering type. The regulator generally
includes a valve assembly 232 which is adapted to control the entry of
fuel into the fuel bowl 168, a diaphragm assembly 234 which is utilized
to control the opening and closing of the valve assembly 232, and a
biasing spring assembly 236 which is utilized to bias the diaphragm
assembly 234 in the downward direction tending to open the valve assembly
232.
The pressure regulator assembly 230 is adapted to control the
pressure of fuel within the fuel bowl cavity 238 from a source of fuel
supply at the tank described above in conjunction with FIGURE 1. The
tank is connected to an inlet connector 242 which, in turn, is connected
to the throttle body by means of mating threads 244 formed on the
exterior of connector 242 and the interior of a cavity 246 formed in the
throttle body. The fuel is filtered through a filter assembly 248
inserted in the cavity 246, the filter being urged inwardly by the
tightening of connector 242 and outwardly by means of a bias spring 250.
Accordingly, fuel flows into the central cavity of the filter and radially
outwardly through the filter medium into the cavity 246, up through a
passageway 252, to the metering valve 232.
-24-
lQC~83~3
The metering valve 232 consists of a valve seat 256 which has
an aperture 258 formed therein through which the fuel flows. The upper
portion of the passageway 258 has a constricted metering orifice and a
valve seat portion, the valve seat being adapted to mate with a ball and
stem member 260. The ball and stem member 260 has an upper stem 262
which is adapted to engage the diaphragm assembly 234, and a lower stem
264 which is utilized to guide the ball and stem member 260 within the
aperture 258. The ball and stem member 260 is resiliently urged upwardly
by means of a spring element 268, the bias of the spring element being
overcome by the diaphragm assembly 234 and spring assembly 236 in the
absence of sufficient fuel in the fuel bowl cavity 238. As will be seen
from a further description of the fuel injector, the injector is
generally of an open configuration up into the chamber 238. If the
fuel supply is depleted in chamber 238, the diaphragm assembly will move
downwardly to open valve ball and stem member 260 thereby permitting
fluid to run into the chamber 238.
The diaphragm assembly 234 includes the diaphragm 182 which acts
as a gasket member between throttle body 141 and the cover member 146,
and also acts as a flexible closure member for the fuel cavlty 238. The
central portion of the diaphragm 182 includes an aperture formed therein
which is adpated to accommodate a rivet-like actuator plate member 274.
The diaphragm assembly 234 further includes a washer member 276 positioned
on the fluid cavity side of the diaphragm 182 and a generally cup-shaped
washer 278 which is positioned on the opposite side of the diaphragm
from the fluid cavity. The cup-shaped washer 278 is utilized to
positîon the lower portion of a spring 280 forming part of the spring
assembly 236. The upper part of the spring 280 is positioned within
the housing 146 by means of an inverted hat-like retainer 284. The
vertical position of the retainer 284 is adjustable by means of a
-25-
- 10983~3
threaded stud 290, the upper end of which is accessible from the exterior
of the cap 146 which, when rotated, will vertically move the position
of the retainer 2~4. A suitable vent hole 292 is formed in the housing
member 146 to permit venting of the interior of closure member 146 to
amb~ent air inlet pressure which also exists at the outlet of the injectors.
In operation, fuel enters the filter assembly 248 from the
connector and flows into the passageway 252. If fuel in the fuel cavity
232 is depleted, the diaphragm assembly 234 will move downwardly to
urge ball and pin member 260 downwardly. This movement will open the
valve assembly 232 to permit fuel to flow into the cavity 238. As the
pressure within cavity 238 builds up to the desired regulated pressure,
the valve assembly 232 is closed. There is provided a bypass vent tube
294 which communicates the interior of the fuel chamber 238 with the
tank through a hose connector (not shown). Accordingly, a small amount
of fuel is continuously vented to the tank to remove any vapor from the
fuel bowl cavity 238. It will be recalled that the injector is of the
non-enclosed type whereby any vapor bubbles formed adjacent the valve
will be permitted to flow to the top of the fuel bowl chamber 238. These
vapor bubbles and any other vapor formed within the chamber 238 will be
vented from the fuel bowl chamber 238 by means of the bypass vent 294.
It has been found that the hot fuel handling of the engine can be
improved by varying the diameter of the bypass vent whereby the time
for starting the car after a hot soak would decrease as the diameter
of the bypass vent was increased. The vent must be significantly smaller
than the inlet to permit pressure bu~ldup in the bowl.
As generally stated above, the pressure regulator illustrated
in FIGURE 8 is particularly adaptable for use with an intermittent flow
pump having intake and discharge portions of a pump cycle. Oresuch pump
is typically used in internal combustion engines in automobiles and
comprises a cam operated diaphragm pump which, on the discharge portion
-26-
tQ'a83~3
of the cycle, pressurizes the fuel system. On the intake portion of
the cycle, flow to the system is not provided by the pump.
Accordingly, the diaphragm 182 an~ fuel chamber 238 act as an
accumulator whereby fuel being fed to the injectors and to the bypass
conduit 294 is pressurized by the action of the diaphragm 182 and the
spring 280. In this way, the intermittent operation of the pump is
smoothed to provide a substantially constant pressure to the injectors.
A check valve is provided in the fuel supply line to produce reverse
fuel flow.
Referring now to FIGURE 9, there is illustrated a modified
form of the pressure regulator described in conjunction with FIGURE 8.
Particularly, a bypass metering type pressure regulator 300 is illustrated,
the pressure regulator 300 including the identical spring bias assembly
236 being utilized as was described in conjunction with FIGURE 8.
However, a diaphragm assembly 302 utilized in this pressure regulator,
is different in that a wobble plate 304 is attached to a diaphragm 306
by means of a ball and fastener assembly 308. The ball and fastener
assembly includes a ball element 310 which is suitably carried within a
housing to permit the ball to move to a limited degree relative to the
diaphragm 306. In this way, the plate 304 is capable of being mated with
an upstanding tube 312 which forms the outlet for the bypass metering
pressure regulator. The upstanding tube is connected in fluid
communication with an outlet conduit 316 to permit fluid to flow from
the fuel bowl chamber 238, through the upstanding conduit 312 and
back to the tank through the conduit 316.
In operation, fuel is introduced to the chamber 252 through the
filter assembly 248 from the fuel tank and into the fuel bowl chamber 238
through a conduit 320 in fluid communication with the fuel bowl chamber 238.
As pressure bui7ds up within the fuel chamber 238, the diaphragm assembly
302 is moved upwardly to move plate 304 away from the upstanding conduit 312
and thereby open the valve. The position of the plate 304 relative to
10~8393
the upstanding conduit 312 determines the pressure drop across the
pressure regulator and thus the pressure within the fuel chamber 238.
The general configuration of the pressure regulator is described in U.S.
Patent 3,511,270, issued May 12, 1970, However, that patent does not
disclose the concepts, inter alia of incorporating the pressure regulator
within the throttle body and utilizing the diaphragm as a seal between
the throttle body and the cover for the fuel bowl.
With the pressure regulator of the type disclosed in FIGURE 9,
it is seen that any fuel vapor which forms around the outlet section of
the injector 174 or within the fuel bowl chamber 238 will gather adjacent
the upstanding outlet conduit 312 to be vented to the tank through the
conduit 316. In this way, hot fuel handling is improved over previously
known fuel handling systems.
Referring now to FIGURE 10, there is illustrated the details of
the sonic venturi 214 which fits the aperture formed in the throttle body
141 with a light, press-fit. Specifically, the sonic nozzle is formed
with a converging throat surface 324 which is formed with a .35 inch
radius. The exterior surface 326 is formed with a notch 328 which mates
with the notch 328 illustrated in FIGURE 9. In this way, the sonic
nozzle is press-fitted from the fuel bowl cavity 238 without permitting
the assembler to drive the sonic nozzle through the throttle body into
the throat section. A slightly chamfered surface 330 is formed with a
15 convergent angle to a point above the sonic nozzle as illustrated in
FIGURE lG. A generally constant diameter surface 332 is formed, the
axial length of the surface being approximately .06 inches. The sonic
nozzle then is developed with a diverging section formed by a surface 336,
the diverging section being formed with a 15 angle total or 7 1/2
from the center line of the sonic nozzle. The distance between the upper
end of the sonic nozzle 214 and the notch 328 is selected to be approximately
-28-
lQq83~3
.31 inches while the overall length of the nozzle is 1.06 inches. The
constricted throat in the area of the constant diameter section defined
by surface 332 has a diameter of .165 inches while the overall diameter
of the nozzle at the exterior surface 338 of the divergent section is
.438 inches.
The dimensions given above are for a preferred form of the
sonic nozzle for use in connection with the system of the present
invention. However, it is to be understood that the configuration of
the nozzle may be varied to provide the sonic shock wave in the divergent
portion of the nozzle formed by surface 336 during a large portion of
the operating range of the engine.
Referring now to FIGURES 11-13, there is illustrated the
specific details of a preferred form of the submerged injector being
utilized in conjunction with the system of the present invention. As can
be seen from the drawings, the injector is extremely simple in construction
and has been found to be reliable in operation. The injector uses the
housing of the fuel bowl to contain and pressurize the fuel relative
to the injector. In this way, any vaporization of the fuel in the area
of the outlet valve of the injector is free to rise to the top of the fue1
bowl and subsequently be vented from the fuel bowl to the fuel tank.
The injector consists basically of a frame member 206 to which
is attached a C-type core element 202 of the conventional type. One
leg of the core 202 is provided with a coil 204, the coil, in the
preferred form, being wound of 150 turns of AWG 26 wire. The core 204
is attached to the frame member by means of a set screw 356 to permit
adjustment of the position of core 202 .-elative to the frame 206.
Referring specifically to the frame member 206, it is seen that
there is a cut out formed as a yoke to receive the C-type core 202.
In this way, the set screw 356 will urge the C core toward the other side
-29-
- 10"8393
of the cut out portion to provide a clamp fit between a
leg 362 and the set screw 356.
A lower portion 366 of the frame member 206 is
formed with a circular aperture 368, the aperture being
sized to receive a valve seat member 370 of approximately
.35 inches diameter. The valve seat 370 is formed with an
external groove to receive the 0-ring 220 and also is
provided with a valve seat 372 and a metering orifice 374.
The valve seat is formed by a coining operation with a ball
element, the diameter of the ball element being over-sized
relative to the diameter of ball element 376 forming the
operative part of the valve armature. The valve seat is
coined in accordance with the principles taught in commonly
assigned Canadian Patent No. 1,069,004, issued January 1,
1980 by Alex M. Kiwior. As noted above, the valve seat
member 370 is inserted into the aperture formed in the
throttle body 141, a seal being formed by the 0-ring 220.
The armature portion of the valve assembly is
provided with two balls 376, 380, the two balls being inter-
connected by a rigid stem 382. The armature assembly -s
forced downwardly by means of a biasing spring 386 contained
within a cavity 388 formed in the upper end of the housing
206. The spring compression is adjusted by means of a
set screw 390 threadedly positioned within the aperture
388. The movement of the set screw 390 in the up or down
direction increases or decreases the compression of the
spring 386 to vary the operation of the valve assembly during
the low pulse width operation, as will be explained here-
inafter.
The opening and closing of the valve assembly is
controlled by means of a flat armature member 400 which closes
the open end of the C-core 202 as is common in this type of
electromagnetic assemblies.
-30-
cbr/~-S
- ~a~83~3
The right end 402 of the armature 400 is positioned against the open
face of C-core 202, and particularly leg 404 thereof, and the left end
408 of the aramture 400 is adapted to engage the upper ball 380.
best seen in FIGURE 13, the left end 408 is provided with a slot 410
through which the stem element 382 is passed to position the upper ball
308 above the left end 408 of the armature. The armature 400 is
provided with a coined seat 412, the seat being coined in accordance
with a method similar to the coining of seat 372. The ball 380 is
positioned within the seat 412 and resiliently retained thereby the
spring element 386. A pin 414 is positioned at the lower end of set
screw 390 to form a guide for spring 386.
To provide a preselected force for the opening of the valve
formed by valve seat 372 and ball 376, a preselected air gap must be
provided between armature 400 and C-core 202. In order to provide this
preselected air gap, the upper edge of armature 400 is provided with a
clad material which is nonmagnetic in nature yet provides a good surface
for the coining operation associated with the end of armature 408 and
the movement of the end 402 of the armature relative to the C-core 202.
The clad is designated with reference numeral 420 and its thickness is
greatly exaggerated. It has been found that a clad depth of approximately
.002 inches and fabricated of such materials as copper, aluminum,zinc,
brass, nickel or plastic are suitable for the operation of this injector.
The armature 400 is held against the C-core to the extent
permitted by spring element 386, by means of a spring 422 and a second
set screw 424 has been provided, in cooperation with set screw 356
to permit upward and downward movement of the C-core 202 for static
adjustment. In this way, the static or deenergized air gap of the
electromagnetic assembly, particularly between the area adjacent end 408
and just below set screw 424, may be adjusted.
-31-
- lQq83~3
Accordingly, after assembly of the injector illustrated in
FIGURE 12, the injector is adjusted for both the static and dynamic
operation in accordance with the particular flow required and the degree
of travel desired upon energization of the coil. In order to adjust
the static air gap, the set screws 356 and 424 are loosened and the
core 202 is moved relative to the frame 206 until the desired air gap
between the armature 400 and the leg of the core 202 below the set
screw 424 reaches the desired amount. The set screws are then tightened
and the coil energized. With the coil energized with short duration
pulses, the set screw 390 is adjusted to adjust the compression of
spring 386 to provide the desired flow from the orifice 374. The injector
is then supplied with long duration pulses to determine if sufficient
travel has been provided in the injector to achieve the desired flow.
Referring now to FIGURE 14, there is disclosed a modified form
of the injector illustrated in FIGURES 11-13. Basically, the injectors
are similar with the exception of the adjustment mechanism associated with
spring 386 and the stop for the upper travel of ball 380, the configuration
of the armature 400 and the configuration of the lower end of the valve
assembly as it is interfitted with the aperture formed within the throttle
body.
An armature 430 is provided of the same general configuration
as the armature 400 with the exception that the armature 430 is not clad
as was discussed in conjunction with the armature 400. Rather, the
adjustment for the air gap between aramture 430 and a surface 432 is
provided by adjusting the core 202 in a vertical direction to achieve
the desired air gap. As was the case with the injector of FIGURE 12,
83~3
an end 434 of armature 430 is resiliently urged toward the bottom of
the C-core by means of a spring 422. The right end 436 of the armature
is coined as was the case of armature 400 and a slot is formed therein
to permit the movement of the stem 382 into the seat formed by the
coining of end 436. However, as was stated, in lieu of the clad
arrangement to provide the desired air gap, the C-core 202 is moved
vertically after the set screw 356, 424 have been loosened. The position
of C-core 202 is then maintained by tightening screws 356, 424.
The adjustment ~or the compression of spring 386 and the
provision of the stop for the upward movement of ball 380 is achieved
by adjustment assembly 440, the assembly including inner and outer set
screw members 442, 444, the outer member 444 threadedly enga~ing an
interior bore formed in the throttle body. As is readily apparent from
the configuration shown, adjustment of the threaded member 444 will adjust
the compression of spring 386 and subsequent adjustment of interior
threaded set screw 442 will move a pin 446 in a vertical fashion to adjust
the stop for the upward movement of ball 380.
The actual valve portion of the assembly is modified from that
shown in FIGURE 12 in that the valve seat element 450 is formed of a
diameter slightly less than the diameter of aperture 452. Thus, there is
a loose fit between the outer diameter of valve seat 450 and the inner
diameter 452. The throttle body has been provided with a counter sunk
groove 456 which is adapted to receive a resilient 0-ring 458 therein to
provide the seal between the valve member 450 and the throttle body element
141. It is to be noted that the valve element is identical to that
described in conjunction to F~GURE 12 in that the vatve seat 372 is formed
by an oversized ball in a coining operation, the ball being large relative
to the lower ball 376 of the valve element. The valve element includes a
second ball 380 which is contained within the coined end 436 of the
-33-
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armature 430, the balls 376 and 380 being interconnected by a stem member
382. Again, the coining operations described are those operations
described in co-pending application Serial Number 697,173. Also, the
ball 380 in both cases must be sufficiently positioned into the aperture
formed in its respective frame to preclude unwanted transverse movement.
With the exception of the physical differences, the valves
of FIGURES 12 and 14 operate identically except for the adjustment
required to maintain the air gap between armature 430 and the end 432
of C-core 202. Also, the adjustment for the spring 486 and stem 446
are slightly different. In other respects, the injector is an inexpensive,
generally open injector to permit venting of vapor bubbles from the fuel
bowl to preclude vapor lock.
As stated above, the system of the present invention utilizes a
modified electronic control unit presently being sold by The Bendix
Corporation. With the modified unit, it has been found that the best
distribution of the air/fuel ratio from cylinder to cylinder is achieved
if the injectors are pulsed at 15 before top dead center for the opening
intake valve. FIGURE 15 illustrates the diagram of the intake valve lift
relative to degrees of engine rotation for one manifold plane of an eight
cylinder engine. Specifically, the firing order of the cylinders for
the illustrated engine are cylinders 1, 4, 6 and 7. At 90, 270~ 450
only one valve is open per plane. Fuel injected to arrive at the ~articular
cylinder near this time can only go to the cylinder with the open valve.
The timing of the pulse must lead the 90 point by an amount which allows
for the air in the manifold to be drawn into the particular cylinder with
the valve open. With the system of the present invention, the fuel injection
for cylinder 1 occurs at a point 15 before the illustrated 720 point
and is shown as the start of a pulse occurring before the 720 point.
The end point of the pulse is left indeterminate as the duration of the
pulse, and as will be seen from a description of the electronic circuitry,
is indeterminate without further inDutS as to the engine speed, MAP and
-34-
~83~
throttle position. Similar injection pulses will occur at 15 before
the 180 point, 15 before the 360 point and 15 before the 540 point
for the wave form illustrated. It is to be understood that the other
injector for cylinders 2, 3, 5 and 8 will occur 15 before the 90,
270, 450 and 630 points.
FIGURES16 and 17 illustrate the effect of injection timing on
distribution of air/fuel ratios from cylinder to cylinder for two vehicle
speeds depending on whether the volume of the intake manifold between
the point of injection of the fuel and the intake valve to receive the
fuel charge relative to the cylinder volume is less or greater than
one, respectively. In FIGURE 16, the situation is such that the per
cylinder manifold volume between point of injection of the fuel and the
intake valve is less than the cylinder volume. From the diagram, it is
seen that the best air/fuel ratio spread between cylinders (one air/fuel
ratio) occurs at injection timing of 15 before top dead center. With
the d;agram of FIGURE 17, the per cylinder ;ntake manifold volume between
the throttle throat and the ;ntake valve is greater than the ind;vidual
cyl;nder volume not allowing the fuel to reach the intake valve before
it closes. In th;s situat;on, the a;r/fuel ratio spread between cylinders
is approximately 1.5 and occurs when the ;njection timing 45 before top
dead center. However, it ;s seen that the curve is erratic and may vary
for varying degrees of per cylinder intake volume to cylinder volume rat;os.
Referring now to FIGURE 18, there is illustrated the schematic
diagram of the basic modification circuit which is to be associated with
the electronic control unit characterized above as a standard electronic
control unit. As previously stated, the base pulse calibration of the
standard electronic control unit is reduced by a predetermined multiple,
in this case by a factor of one half, and the base pulse is fed from the
electronic control unit to a gating network 600 by means of a conductor 602.
-35-
1~9l~3~?3
The gating network 600 is utilized to control whether the first injector,
characterized channel A, or the second injector, characterized channel B,
is to be pulsed with the next injector pulse. The operation of the
gating network 600 is controlled by means of a sensor signal fed to an
input terminal 604 and then to a sensor signal processor circuit 606 by
means of a conductor 608. The output of the sensor signal processor
circuit is fed to the gating network 600 by means of a conductor 610.
Accordingly, the sensor signal operates on the gating network to enable
channel A or channel B, the enabled channel being the channel which
receives the base pulse from conductor 602.
The output of the gating network is fed to a channel A multiplier
circuit 614 or a channel B multiplier circuit 616 by means of conductors
620, 622, respectively. The multipliers are utilized to generate an
additional pulse to be added to the end of the base pulse being fed to
the particular multiplier. The multiplier network 614 or 616 then provides
the additional pulse noted having a duration which is a function of the
factor by which the base pulse calibration was initially adjusted. The
multiplier circuit 614 also receives a signal from the electronic control
unit which is indicative of the coolant temperature, the signal taking
the form of a current signal, to control the multiplier pulse duration in
response to coolant temperature. Similarly, the multiplier 616 receives
a coolant temperature signal from the ECU by means of a conductor 626,
this signal being a voltage signal ind~ative of the coolant temperature,
to again operate on the multiplier circuit 616 as a function of coolant
temperature.
The output of the multiplier circuits 614, 616 are fed to a
pair of OR gates 630, 632, the OR gates adding the multiplier pulse to
the base pulse and connecting the composite pulse to driver circuits
634, 636 by means of conductors 638, 640. The driver circuits are
-36-
3~3
utilized to provide the necessary signal characteristics to energize the
injectors and provide a pulse of fuel of preselected quantity to the throttle
body throat. During the initializing of the electronic control unit,
the conductors 638, 640 are grounded by the electronic control unit
through a ground signal impressed on conductor 642. This ground signal
on conductor 642 is generated when initial power is app1ied to the
electronic control unit and the conductors 638, 640 are grounded to
preclude a pulse being fed to the injectors during initializing.
The output pulse to the drive circuits 634, 636 are modified
depending on the particular type of operation being encountered. For
example, the gating network produces signals designated Q on conductor 646
and q on conductor 648, which signals are cold start trigger signals fed
to an OR gate 650 designated cold start trigger. The output of the cold
start trigger is fed to the electronic control unit by means of a conductor
652. In this way, the cold start trigger signals are generated in the
electronic control unit in response to the sensing by the electronic
control unit that the engine is being started. These signals only appear
during the starting phase of vehicle operation. The output of conductors
646, 648 are fed to the input of OR gates 630, 632 by means of conductors
651, 653, respectively. These signals are to control the feeding of
cold start pulses to the output driver circuits 634, 636 from the
standard control unit through conductors 654, 656. The cold start pulses,
designated TPCs, are of longer duration than the composite base and
multiplier puls2s being fed to the OR gate 630, 632 and therefore the
only pulses seen at the driver circuits 634, 636 during cold start are
the cold start pulses.
Referring back to the multiplier circuits 614, 616, it is seen
that the channel A pulse on conductor 620 and the channel B pulse on
conductor 622 are fed forward to OR circuits 630, 632 respectively by means
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8393
of conductors 658, 660, respectively. Accordingly, when a pulse appears
on conductor 620 or conductor 622, these pulses are fed to the respective
OR circuits 630, 632 and then to the respective driver circuits 634, 636
to be utilized to energize the respective injector. Upon termination of
the channel A or channel B pulse, the multiplier circuits 614, 616 take
over and adds to the pulse which has just been terminated by a pulse
generated by the multiplier. Thus, the channel A pulse is added to the
multiplier pulse from multiplier circuit 614 to produce the total TPl
pulse at the output of driver circuit 634. Similarly, the channel B
pulse on conductor 622 is added to by the multiplier circuit 616 to
provide a total TP2 pulse at the output of driver 636.
The system also includes an acceleration enrichment pulse
generating capability, the acceleration enrichment pulse being generated
on a conductor 662, which pulse is fed to the input of OR gates 630, 632
to be added to the multiplier pulse in response to the throttle position
signal on conductor 664. The input signal is fed to a throttle position
current generator circuit 666, the output of which is fed to a pulse width
comparator circuit 668. The comparator circuit 668 also receives the
voltage corresponding to the throttle position by means of a conductor 670.
The pulse width comparator 668 has the capability of sensing both throttle
position and rate of change of throttle position and, by making a
comparison between these signals, will generate an acceleration enrichment
pulse depending on these two factors. This pulse is fed to an OR gate
674, the output of which provides the signal level on conductor 662.
This accelerat;on enrichment pulse is corrected for engine coolant
temperature by means of a coolant temperature correction circuit 676, the
input of which receives a signal indicative of the engine coolant
temperature on an input conductor 678. The length of the coolant
temperature correction pulse from circuit 676 is dependent on two factors.
One being the width of the AE pulse as fed thereto from the pulse width
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lQ~B3~3
comparator circuit 668 on a conductor 680. The other condition, of course,
is the engine coolant temperature.
The pulse width comparator circuit is reset periodically by a
trigger signal from a trigger circuit 684, the trigger circuit being
tr~ggered by either the output of multiplier 614 on conductor 686 or
the output of multiplier 616 as sensed by the signal level on conductor 688.
The trigger circuit 684 resets the pulse width comparator by means of an
output signal on conductor 690.
The system also has the capability of generating a wide-open
throttle (WOT) signal which is utilized in the electronic control unit
~or various functions. This is accomplished by sensing the analog
voltage level of the throttle position sensor output signal on a
conductor 692, this signal being fed to a wide-open throttle signal
generator 694. The signal generator 694 compares the signal level on
conductor 692 with a preselected reference indicative of the wide-open
throttle position. When the wide-open throttle position is sensed, the
standard control unit is fed a signal on conductor 696. It should be
noted that the acceleration enrichment pulses are phased with the normal
injection pulse.
Referring now to FIGURE 19, there is illustrated a modified form
of the acceleration enrichment pulse generator circuit illustrated at the
bottom of FIGURE 18. The circuit of FIGURE 19 is similar in some respects
but adds the capability of providing a slow decay function for the
acceleration enrichment pulse. This has been found to improve the
driveability of the automobile during the operation of the vehicle which
requires an acceleration enrichment pulse. The output of this circuit
is added to the end of the base pulse instead of the multiplier pulse.
Specifically, the circuit 700 includes a throttle position current
generator circuit 702 which receives an input signal from a linear throttle
position potentiometer at conductor 704. The standard electronic control unit
supplies a base pulse to a trigger circuit 70~ by means of a conductor 70~.
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83~
The outputs of the throttle position current generator 702 and the trigger
circuit 706 are fed to a pulse width comparator circuit 712 by means of a
conductor 714, the output of the pulse width comparator circuit 712
being utilized to generate an acceleration enrichment pulse on output
conductor 716. As was the base previously, the throttle position current
generator supplies the operative signal to the pulse width comparator
and the trigger circuit 706 periodically resets the pulse width comparator.
The circuit also includes a slow decay differentiator circuit
720 which receives an input from the linear throttle position potentiometer
on input conductor 722. The slow decay differentiator circuit 720
provides an "after transient" decay function on output conductor 724
to be fed to the pulse width comparator. This function is proportional
to the rate of change of throttle position and the output of the pulse
width comparator circuit 712 will no longer be the sharp transient
described in conjunction with FIGURE 18 but rather will have an exponential
decay characteristic.
As was the case with FIGURE 18, the circuit provides a means for
generating a wide-open throttle signal by means c,f a signal generator
circuit 730 which receives an analog throttle position signal proportional
to throttle position from the throttle potentiometer. The output of
the wide-open throttle signal generator is fed to the standard electronic
control unit by means of a conductor 734 to be used for the purposes
normally inherent to the electronic control unit.
Referring now to FIGURE 20, there is illustrated the circuit
schematic details of the upper half of the block diagram illustrated in
FIGURE 18. Specifically, the base pulse from the electronic control unit
is fed through a buffer amplifier 750, the base pulse being fed to the
buffer amplifier from the electronic control unit at input terminal 7~2.
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~ 0~8393
The input to the operational amplifier at conductor 602 is a modified
base pulse wherein the normal calibration of the base pulse has been
modified by some fraction and impressed on conductor 602. The modified
base pulse is fed to a pair of resistors 754, 756 corresponding to
channel A and channel B, respectively.
The determination of whether the base pulse is to be fed to
channel A, one injector, or channel B, the other injector, is controlled
by means of a crankshaft position sensor which generates the sensor signal
which is fed to a sensor signal processing circuit 606. The circuit 606
provides the output signal on conductor 610 to determine which channel
the base pulse is to be fed. Referring to the specific details of the
circuit 606, an input trigger signal from an engine position sensor
device is fed to the input conductor 60~. In the particular system
being illustrated, the cr~nkshaft position sensor takes the form of a
disc having two lobes formed thereon, each lobe being 90 in angular
length and being spaced 90~ apart. Accordingly, a positive spike is
generated each time, for example, the engine passes through 90 or 270
of rotation and a negative spike is generated each time the engine passes
through 180 and 360.
This input trigger signal is fed to a pair of voltage comparators
760, 762, the voltage comparators 760, 762 being connected to control the
set and reset conditions of an output flip flop 764. The output of the
fl~p flop 764 takes the form of a 50% duty cycle square wave. The output
of the flip flop 764 is made to control the gating network by providing
an output circuit including an open collector transistor 766 which is
connected to the output conductors 610
This input trigger signal is fed to a pair of voltage comparators
760, 762, the voltage comparators 760, 762 being connected to control the
set and reset conditions of an output flip flop 764. The output of the
flip flop 764 takes the form of a 50% duty cycle square wave which is
similar to the output of a Hall effect device. The output of the flip
flop 764 is made substantially identical to the Hall effect device by
providing an output circuit including an open collector transistor 766
which is connected to the output conductors 610.
Bias for the voltage comparators 760, 762 is provided during
the period when the ignition is on by means of a signal fed to an input
conductor 768, the negative bias being fed to the inverted input of
- - ~ Q~83~3
operational amplifier 760 by means of a conductor 770 and a resistor 772.
Negative bias is provided to amplifier 762 when the ignition is on by
means of conductor 768 and a resistor 776. The operational amplifier 762
is also provided positive bias from the conductor 768 by means of a
resistor 778. During cranking, the operational amplifier 760, 762 are
increased in sensitivity by providing a 4.7 volt potential at the positive
inputs thereof by means of resistors 782, 784. This positive bias
is provided from a crank signal fed to an input conductor 786 which provides
current to break down a zener diode 788 through a resistor 790.
Accordingly, when the engine is cranking, the positive and
negative signals from the crankshaft position sensor associated with the
engine are fed from conductor 608 to operational amplifiers 760 by means
of a resistor 792 and to the negative input of operational a~plifier 762
by means of a resistor 794. The added positive current to operational
amplifier 760 from the positive yoing spike will provide an output signal
in the form of a pulse from operational amplifier 760 to set flip flop 764.
On the other hand, when the negative spike is sensed on conductor 608,
the operational amplifier 762 resets flip flop 764. This provides a
logical 1 and logical O signal at the output of flip flop 764
This siynal on conductor 610 controls the conductive condition
of a transistor 800 through a base driver resistor 802. Accordingly,
when the voltage on conductor 610 is high, the transistor 800 wlll be
conducted to shunt the current through resistor 756 to ground to cause
the pulse on conductor 602 to be fed through resistor 754. On the other
hand, when transistor 800 is cut off due to a low signal on conductor
610, the signal is fed through resistor 756 and the signal on resistor
754 is shunted through a diode 806.
Therefore, a base pulse which is directed through channel A is
fed through an inverter 808 and a base pulse which is to be utilized in
-42-
~983~3
channel B is directed through an inverter 810. It is to ~e noted that
the trigger signal after it is processed by the signal sensor processor
606 is fed to the standard control unit by means of a transistor 816,
the transistor 816 signalling the standard control unit to initiate a
base pulse.
The system also includes a cold start trigger circuit 650 which
is provided the 50% duty cycle engine position sensor signal on conductor
610 by means of a conductor 818. The pulse start circuit includes a
capacitor 820, resistor 822 combination, and an inverter 824, capacitor
826 and resistor 828 combination. The signals on the outputs of these
networks are fed through a pair of diodes 830, 832, respectively, to
provide positive spikes at output terminal 652 each time the signal on
conductor 610 changes state. Accordingly, output trigger pulses will be
generated at terminzl 652 and fed to the standard control unit, four
times per engine revolution for an eight cylinder engine. These pulses
to the standard control unit are utilized to generate the cold start
signal pulses which overlap the normal base pulse and, in fact, are of
sufficient duration to mask the entire base pulse. This will be
explained more fully hereinafter.
Assuming for example that channel A is selected to receive the
next base pulse, the incoming base pulse will provide a control for
transistor 836. When the incoming channel A base pulse at resistor 754
is high, the inverter 80& will invert the signal and cause transistor 836
to cease conduction. This will permit capacitor 838 to charge from a
constant current source developed through the emitter-collector circuit of
a transistor 840. When signal on channel A goes high, the transistor 836
is turned on to lower the left side of capacitor 838 to ground. With the
negative transistion of the left side of capacitor 838, the right side
of capacitor 838 will also make the same transistion to cause the capacitor
838 to again charge from a constant current from the standard ECU on
terminal 848.
-43-
~a83~3
The right side voltage of capacitor 838 is fed to the base electrode ofa transistor 846, the capacitor being supplied by the constant current
source being supplied by the input conductor 848 connected to sense engine
p , TH20~ from the standard control unit This current
is a constant current, the magnitude being dependent on the temperature
of the engine coolant. An identical multiplier exists below for channel
B and the transistor corresponding to transistor 836 is designated
transistor 856. The channel B pulse going positive causes transistor 856
to cease conduction thereby permitting capacitor 858 to charge from a
constant current source created by transistor 860. When the pulse B goes
to zero, the transistor 856 is turned on, causing a negative voltage
transition of the left side of capacitor 858. This same negative transition
is seen at the base of transistor 870, causing it to turn off until the
constant current from the collector of transistor 862 recharges the right
side of capacitor 858 back to about positive 0.6 volt, at which time
transistor 870 conducts again, its collector voltage going to ground.
The current in the collector of transistor 862 is dependent on engine
coolant temperature. Thus, the recharge slope on the right side of
capacitor 858, and the multiplier pulse width output, depends on engine
coolant temperature. The output pulse duration is the time that transistor
870 is turned off.
Accordingly, an additional pulse is yenerated on conductors 686
or 688, the starting point of which depends on the base pulse and the
duration of the pulse is proportional to coolant temperature. The pulse
on conductor 688 is generated from the collector electrode of trans;stor 870.
In this regard, attention is directed to FIGURE 21 wherein is
illustrated the slope at the base of transistor 846, the transistor ~eing
designated Q15 in FIGURE 21. The positive slope is seen to be proportional
to engine temperature. The second diagram of FIGURE 21 illustrates the
output of the transistor 846, again designated nl5 at point C, point C
being illustrated in the drawings. The following figure illustrates the
A pulse relative to the operation of transistor 846 and the fourth
-44-
~ 9~3~3
figure represents the voltage at the collector of transistor 836.
Accordingly, by correlating the various figures of FIGURE 21, the
operation of the transistors 836, 846, the charge and discharge of
capacitor 838 and the output pulse at point C will be seen.
This operation is similar for transistors 856 and 870 and capacitor 858.
The output of the transistor 846 is fed to the OR gate 630 and
the output of transistor 870 is fed to OR gate 632. Specifica11y, the
multiplier pulse is fed through a resistor 880 to the non-inverting
input of an operational amplifier 882. The inverting input is connected
to a sou-rce of positive potential. On the other hand, the collector
voltage of transistor 870 is fed to the noninvertina input of an operational
amplifier 884 through a resistor 886. It will be seen that nodes 890
and 892 are summing nodes for channels A and B, respectively. Accordingly,
the base pulse on conductor 658 is fed to the node 890 by means of a
resistor 894 and the pulse from transistor 846 is also fed to the node 890
by means of resistor 880. The base pulse on conductor 660 is fed to
node 892 through a resistor 896 and the collector signal of transistor 870
is fed to the node 892 by means of resistor 886.
It will be seen that the nodes 890 and 892 also include
acceleration enrichment pulses fed to node 890 by means of a terminal 900
in the case of node 890 and to node 892 acceleration enrichment pulses
are fed through a terminal 902. The node 890 is also fed a cold start
pulse which is impressed on input terminal 656 from a cold start circuit in
the standard electronic control. The pulse on terminal 656 is
controlled by the Q pulse at input terminal 906. A similar situation
exists wherein cold start pulses are fed to node 892 by means of terminal
656 and the pulses therein are controlled by an input signal fed to a Q
input terminal 908.
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83~
Accordingly, the output of operational amplifier 882 will
provide an output pulse to a current driver for the injectors
any time one of the in~ut pulses appears at node 890- Accordingly,
a base pulse may be fed to terminal 890 and subsequently a multiplied
pulse from transistor 846 fed to node 890. If acceleration enrichment is
desired, then a pulse will be added to the end of a multiplier pulse by
means of a pulse fed to terminal 900. If a cold start pulse is required,
then the cold start pulse is fed to output terminal 910 through node 890
and operational amplifier 882, the cold start pulse being longer than
the duration of the sum of the pulses previously described. The output
pulse on terminal 910 is also fed to the electronic control unit connected
to terminal 916 through a diode 918. The channel B circuit is identical
and need not be explained further here.
The signal on conductor 916 is utilized for svstem initiali-
zation when energy is applied to the standard control unit (ECU), the
terminal 916 is momentarily grounded to ensure that no pulses appear at
terminals 910 or 920 which would thereby inject an uncontrolled pulse of
fuel into the engine.
Referring now to FIGURE 22, the signal levels on conductors 686
and 688 are fed to a pair of inverter circuits930, 932. Accordingly,
every time that the pulse level on either conductor 686 or 688 goes from
a high to a low level, the output of inverters 930 or 932, respectively,
will go from a low to high level. hccordingly, on the rising edge of
the output of lnverter 930, an output spike will be produced across
resistor 934 due to the differentiation action of capacitor 936.
Similarly, a rising edge signal at the output of inverter 932 will create
a positive spike across resistor 938 due to the action of capacitor 940.
-46-
10~3~
These rising spikes are fed to a summing node 944, which in turn control
the conduction of a transistor 948. The output of transistor 948 may
or may not produce an acceleration enrichment pulse depending on other
conditions to be discussed hereinafter.
The throttle position is sensed by means of an analog
potentiometer which provides an input signal at an input terminal 950.
This analog signal is fed to an operational amplifier 954 appearing on
capacitor 956. Accordingly, the voltage at the input of operational
amplifier 954 will be approximately the potentiometer voltage at input
terminal 950 but shifted up slightly. This voltage causes transistor
960 to conduct and provide a current through resistor 962 which is
corresponding to the throttle position sensed at input terminal 950.
A mirror-current circuit 964 is provided whereby the current through
transistor 966, which is also the current through transistor 960, is
induced in the emitter-collector path of a transistor 968. Accordingly,
the emitter-collector current of transistor 968 is utilized to charge the
capacitor 970 through a conductor 972.
Re~erring now to the operation of a comparator 976, it will be
seen from a descript~on below that the comparator 976 generates an
acceleration enrichment pulse. The charge on capacitor 970 is fed to
the inverting input of comparator 976 through a resistor 978. Normally,
this input voltage is kept slightly above the voltage at the non-inverting
input sothat the output of comparator 976 is kept in the low state.
This is true even when capacitor 970 is discharged to ground which occurs
when transistor 948 commences conduction each time a positive spike is
generated at node 944.
However, the non-inverting input to comparator 976 is rendered
throttle position rate of change responsive in that a differentiator
network is provided which includes a resistor 980 and a resistor 982 and
-47-
-~ lQg8393
and a capacitor 984. The throttle position rate of change is fed to the
differentiator circuit from input conductor 670, the signal level thereon
be~ng representative of the instantaneous throttle position. If there is
a transient, indicating that the throttle is being moved forward,
the voltage at the non-inverting input to the comparator 976 will rise.
If the non-inverting input is at a higher voltage when the normal pulse
terminates, as sensed by the spike a node 944 thereby discharging
capacitor 970, the comparator will provide output at output conductor 990.
Resistor 992 is provided as a hysteresis resistor to preclude the
comparator from oscillating.
The output pulse duration at conductor 990 is determined by the
rate of change of the throttle position as indicated by the magnitude of
the signal at the non-inverting input to comparator 976. Also, because
the capacitor 970 will start to charge upon termination of the spike at
node 944, and the charge rate of capacitor 970 is determined by the
throttle position, the output pulse width is also dependent on throttle
pos~tion. Accordingly, if the Magnitude of the input at the non-inverting
terminal is high and the throttle position is low, the output duration at
conductor 990 will be long.
As noted above, the output acceleration enrichment pulse is
corrected for temperature by means of the circuit 67~. The TPAE pulse is
inverted by means of an inverter 996, the output of which is fed to the
base electrode of a transistor 998 through a resistor 1000 The circuit
illustrated at 676 is similar to the mult~pl~er described above in
conjunction with the description of FIGURE 20. Accordingly, when the
base electrode of transistor 998 goes low, a capacitor 1002 is charged
from a source of voltage through a resistor 1003. A zener diode 1006 is
provided to keep the collector voltage of transistor 998 from exceeding
a preselected value. When the base electrode of transistor 998 goes
high, the left side of capacitor 1002 has a negative transistion which
causes a corresponding negative transistion on the right side of capacitor 1002.
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1~983~;~
The capacitor then commences charging from a current source made up of a
transistor 1110 and its emitter resistor, the current through the transis-
tor 1110 being dependent on the temperature of the vehicle coolant.
Accordingly, the source for charging capacitor 1002 from transistor 1110
will be temperature dependent. This current feeds the base of transistor
1112 and the collector of transistor 1112 will remain in a high or off
state until the base electrode circuit charges back up to a voltage
sufficient for conduction of transistor 1112. This time duration is
dependent on the width of the input pulse fed to transistor 998 and the
temperature of the engine coolant as sensed by transistor 1110.
The pulse generated at the collector of transistor 1112 and fed
to the output conductor 662 through diode 1114 is added to the pulse
being fed directly from conductor 990 to conductor 662 through a diode
1116, increasing the width of the acceleration enrichment pulse depending
on coolant temperature.
The system also includes a wide-open throttle signal which is
generated by circuit 694 which includes an operational amplifier 1120,
the noninverting input of which receives an anlog signal dependent on the
throttle position through a resistor 1122. Accordingly, the signal level
at output conductors 696 switches to a high state at a sensor voltage
corresponding to wide-open-throttle. This signal is fed to the ECU.
Referring now to FIGURE 23, there is illustrated a modified form
of the circuit described in conjunstion with the description of FIGURE 22.
Specifically, the coolant temperature compensation circuit is eliminated
and the warm-up factors generated in the standard electronic control unit
to increase the width of the base pulse are utilized to correct the
acceleration enrichment pulse width according to engine coolant temperature.
The acceleration enrichment pulse generated by the circuit of FIGURE 23 is
then added to the base pulse width in conjunction with FIGURE 20 and
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1~83~;~
the sum of the two pulses is operated on by the multiplier
to produce the final output TP pulse. Additionally, the circuit of
FIGURE 23 provides a transient decay function which maintains the
acceleration enrichment pulse on a decay function basis after the end
of the throttle position transient.
Referring to the specific details of FIGURE 23, the voltage
from the throttle position potentiometer is fed to the input terminal
704 to charge a capacitor 1130 through a resistor 1132. The voltage
level at input terminal 704 creates a charge on capacitor 1130 which is
fed to an operational amplifier 1134. The output of the operational
amplifier controls the conduction of a transistor 1136, the current
through the collector-emitter circuit of transistor 1136 being reflected
in the current flowing in a conductor 1138. This is due to the fact
that the current flowing in the collector-emitter circuit of transistor
1136 is substantially the same current that is flowing in a transistor 1140.
The conductive level of transistor 1140 is reflected to the emitter-base
circuit of a transistor 1142 to cause transistor 1142 to conduct to the
same degree that transistor 1136 is conducting.
Thus, a current flows in conductor 1138 to charge a capacitor 1146
with a current supply which is directly proportional to the throttle
position sensed at input terminal 704. The normal running base pulse
generated in the ECU is fed to input terminal 1150, the termination of
the normal running base pulse causing transistor 1152 to conduct
momentarily due to the differentiation action of a capacitor 1154 and a
resistor 1156. The conduction of transistor 1152 will cause a transistor
1160 to conduct thereby momentarily discharging capacitor 1146.
Accordingly, if the circuit of FIGURE 23 is to provide an acceleration
enrichment pulse, the pulse will be initiated at the end of the normal
running base width. The charge on capacitor 1146 is fed to the inverting
input of an output operational amplifier 1166 through a resistor 1168.
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~83~
The operation of the comparator 1166 is substantially identical
to the operation of the output comparator described in conjunction with
FIGURE 22 Referring now to the lower half of FIGURE 23, the throttle
position signal is being fed to an input terminal 1170 and from there
through a low pass filter circuit 1172 and differentiator circuit 1173
to provide a voltage proportional to the rate of change of throttle position
at the non-inverting input of an operational amplifier 1176 by means of a
resistor 1178 and a conductor 1180. The output of the operational ampli-
fier is utilized to charge a capacitor 1184, the charge on capacitor 1184
being fed through an operational amplifier 1186 and, then, to the non-
inverting input of operational amplifier 1166 by means of a resistor 1188.
The operational amplifier 1166 is set up such that when there is no
transient signal being passed through resistor 1188, the voltage on the
non-inverting input to comparator 1166 is below the lowest voltage appear-
ing at the inverting input. However, if a transient has occurred, the
voltage input to the non-inverting portion of comparator 1166 is greater
than the voltage at the inverting input to provide an output pulse at an
output terminal 1190. The output pulse at terminal 1190 is the acceleration
enrichment pulse described above.
The duration of the pulse at terminal 1190 will be determined by
the rate of charge of capacitor 1146 and the magnitude of the rate of
change of throttle position as fed to the non-inverting input of comparator
1166.
As stated above, the charge on capacitor 1184 during the transient
of the throttle is determined by the magnitude of the rate of change of
throttle position. The capacitor 1184 does not immediately discharge
when the transient condition ceases to exist but rather discharges slowly
through the discharge circuit including resistor 1194 and resistor 1196.
-51-
1~83~3
Thus, the signal being fed to the non-inverting input of comparator 1166
is maintained after the transient has ceased to exist. In this way,
a decay function is provided after the cessation of the transient
condition.
The circuit of FIGURE 23 also includes a wide-open throttle
signal which is generated by a wide-open throttle comparator circuit 730
including an operational amplifier 1200, the non-inverting input of the
operational amplifier being fed a throttle position signal through a
resistor 1202. The output of the operational amplifier 1200 is fed to
theelectronic control unit connected to output terminal 1204.
While it will be apparent that the embodiments of the invention
herein disclosed are well calculated to fulfill the ob~ects of the
invention, it will be appreciated that the invention is susceptible to
modification, variation and change without departing from the proper
scope or fair meaning of the subjoined claims.
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