Note: Descriptions are shown in the official language in which they were submitted.
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MONITORING T~IE OPERATION OF AN
INTERNAL COMBUSTION ENGINE
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THIS INVENTION relates to monitoring the operation
of an internal combustion engine. More particularly, it
relates to a method of monitoring the operation of such
an engine and to a monitoring device for use in such method.
The invention finds particular application in the
monitoring of a vehicle engine during driving, for purposes
of promoting driving habits which result in economic
utilization of fuel, and providing vehicle fleet operators
with a management tool for use in monitoring the driving
habits of drivers.
Applicant is aware of a warning device for use in
a vehicle having an internal combustion engine, which device
comprises a diaphragm type actuator arranged to actuate an
electrical switch. The switch is connected in series with an
electrical warning light to a source of electric current,
and the diaphragm type actuator is connected to the inlet
manifold of the engine. The operation of the device is such
that, when the degree of vacuum in the inlet manifold falls
below a predetermined value, the switch is closed, causing
the warning light to be actuated. .
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This will then be an indication to -the driver of the vehicle
tha-t the engine operating conditions are such as to lead to
uneconomic utiliza-tion of fuel.
Applicant is also aware of a device for use in
a vehicle having an internal combustion engine, which device
comprises a diaphragm type actuator and a mechanically operated
counting device arranged to be acted upon mechanically by the
diaphragm type actuator when the degree of vacuum in the
engine's inlet manifold falls to below a predetermined value,
to record a count on the counter.
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Applicant has found that when the devices referred
to above are adjusted to provide a warning signal or a
recording when the degree of vacuum falls to a value at which
there is uneconomic utilization of fuel, at low engine speeds,
then the driver is able, by gradually increasing the speed
of the vehicle, to obtain a relatively high speed without a
warning signal being issued or a recording being made. At
such high speeds there is again uneconomic utilization of
fuel. However, if the devices are adjusted to provide a
warning signal or a recording when there is uneconomic
utilization of fuel at high engine speeds, then the devices
become so sensitive at low engine speeds that the slightest
acceleration results in a warning signal being issued or a
recording being made. This is frustrating to the driver
and inhibits smooth traffic flow.
Another disadvantage of the device described above
having a mechanical counter is that it provides a single
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count whenever the degree of vacuum falls below the pre-
determined value, regardless of the length of time for which
the degree of vacuum remains below that value. The r~ading on
the counter will therefore be of little value to a fleet
operator, as the driver can keep the reading on the counter at
a low value by driving in such a manner that the degree of
vacuum in the inlet manifold remains at low, uneconomical
levels for long stretches of time.
It is an object of the present invention to overcome
or at least mitigate the above disadvantages.
According to the invention there is provided a method
of monitoring the operation of an internal combustion engine
having inlet ducting for admitting air or a fuel/air mixture
`into the engine, which method comprises
sensing the degree of vacuum in the inlet ducting and
providing a vacuum signal when said vacuum falls below a
predetermined vacuum level;
sensing the rotational speed of the engine and providing a
first speed signal when said rotational speed exceeds a first
predetermined speed value and a second speed signal when said
rotational speed exceeds a second predetermined speed value
greater than the first predetermined speed value;
gating the vacuum signal and the second speed signal to
provide an enabIing signal when either said vacuum signal or
said second speed signal, or both said vacuum signal and said
second speed signal, are present; and
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issuing a warning signal and/or makiny a recording under
operational conditions of the engine in which both the first
speed signal and the enabling signal are present.
The vacuum signal may be a first vacuum signal, and
the predetermined vacuum value a first predetermined vacuum
value; the method further comprising providing a second vacuum
signal when said vacuum falls below a second predetermined
vacuum value greater than the first predetermined vacuum value,
said gating including gating the second vacuum signal so as to
provide said enabling signal when said first vacuum signal
and/or both said second vacuum signal and said second speed
signal are present.
The recording may be such as to be indicative of the
length of time for which the engine operates under said
operational conditions.
Further according to the invention there is provided
a monitoring device for use in monitoring the operation of an
internal combustion engine having inlet ducting for admitting
air or a fuel/air mixture into the engine, which monitoring
device comprises:
vacuum se~nsitive means for sensing the degree of vacuum in
the inlet ducting and being operative to provide a vacuum
signal when said vacuum falls below a predetermlned vacuum
value;
speed sensitive means for sensing the rotational speed of
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the engine and being opera-tive to provide a first speed signal
when said rotational speed exceeds a first predetermined speed
value and a second speed signal when said rotational speed
exceeds a second predetermined speed value greater than the
first predetermined speed value;
gating means which is operative in response to the speed
sensitive means and the vacuum sensitive means to provide an
enabling signal when either said vacuum signal or said second
speed signal, or both said vacuum signal and said second speed
signal are present; and
warning means and/or a recorder which is operative in
response to the first speed signal and the enabling signal to
- issue a warning signal and/or make a recording under operational
: conditions of the engine in which both the first speed signal
~ 15 and the enabling signal are present.
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The vacuum signal may be a first vacuum signal, the
predetermined vacuum value may be a first predetermined vacuum
value, the vacuum sensitive means may further be operative to
provide a second vacuum signal when said vacuum falls below a
second predetermined vacuum value grea-ter than the first
: predetermined vacuum value, and the gating means may be first
gating means;
the apparatus further comprising second gating means, the
first gating means being operative in response to the speed
sensitive means and the vacuum sensitive means via the second
gating means to provide said enabling signal when said first
vacuum signal and/or both said second vacuum signal and said
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second speecl signal are present.
The recorder may be adapted and arranged to make a
recording which is indicative of the length of time for which
the enyine operates under said operational conditions.
Still further according to the invention there is
provided a motor vehicle comprising an internal combustion
engine having inlet ducting for admitting air or a fuel/air .;~
mixture in~o the engine, vacuum sensi-tive means arranged to
sense the degree of vacuum in the inlet ducting and being
operative to provide a vacuum signal when said. vacuum falls
below a prede-termined vacuum value, speed sensitive means
arranged to sense the rotational speed of the engine and being
operative to provide a first speed signal when said rotational
speed exceeds a first predetermined speed value and a second
; 15 speed signal when said rotational speed exceeds a second
predetermined speed value greater than the first predetermined
speed value, gating means which is operative in response to the
speed sensitive means and the vacuum sensitive means to provide
an enabling signal when either said vacuum signal or said
second speed signal, or both said vacuum signal and said second
speed signal are present; and warning means and/or a recorder
which is operative in response to the first speed signal and
the enabling slgnal to issue a warning signal and/or make a
recording under operational conditions of the engine in which
~5 both the first speed signal and the enabling signal are
present.
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The invention will now be described in more detail,
by way of example, with reference to the accompanying draw-
ings.
In the drawings:
Figure 1 is a schematic diagram o a monitoring
device in accordance with the invention, installed in a
motor vehicle;
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Figure 2 is a graph illustrating the operation of the
device of Figure l; and
Figure 3 is a graph illustrating the operation of an
alternative embodiment of the invention wherein the predetermined
vacuum value at which warning signals are issued ~nd a
recording is made is a stepwise increasing function of
engine rotational speed, increasing in three steps, instead
of in two steps as is the case with the device of Figure 1.
Referring now to Figure 1, reference numeral 100
generally indicates a monitoring device which is connected
to inlet ducting 102 for admitting a fuel/air mixture into
the internal combustion engine of a motor vehicle.
The inlet ducting comprises a barrel 104 of the vehicle's
carburettor, the carburettor having a butterfly valve 106
for regulating the rate of flow of the fuel/air mixture into
the engine. The inlet ducting 102 further comprises an inlet
manifold 108 (shown in dotted lines) leading to the various
cylinders of the engine.
The monitoring device 100 comprises vacuum sensitive
means 110 in the form of two diaphragm devices 112.1 and
112.2 secured to a common mounting bracket ~not shown). The
two diaphragm devices are similar in construction and,
although only the diaphragm device 112.1 will be described
below, the description will apply equally to the diaphragm
25~ device 112.2, the parts of the diaphragm device 112.2 in the
drawing being indicated by the same reference numerals as
those of the diaphragm device 112.1, èxcept that they are
followed by a suffix 2 instead of a suffix 1.
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The diaphragm device 112.1 has a diaphragm housing
114.1 mounted on the mounting bracket, a diaphragm 116.1,
and a rod 118.1 connected -to the diaphragm 116.1 and protruding
from the housing 114.1.
The diaphragm housing 114.1 is connected to the
interior of the carburettor barrel 104 at a point downstream
of the butterfly valve 106 by means of a tube 120.1. The
tubes 120.1 and 120.2 of the diaphragm devices 112.1 and
112.2 are interconnected by means of a T-connection 122.
On the rod 118.1 there is provided an actuating
collar 124.1. There is further provided a micro-switch
126.1 which is arranged to be actua-ted by the actuating
collar 124.1. The micro-switch 126.1 is mounted in such a
manner on the mounting bracket that it is slidably adjustable
in a direction parallel to the longitudinal direction of the
rod 118.1. Alternatively, or in addition, the actuating
collar 124.1 may be adjustably mounted on the rod 118.1 so
as to permit adjustment of the longitudinal position of the
: actuating collar on the rod 118.1. The free end of the rod
118.1 is guided in a guide 128.1 which is fixed in relation
to the mounting bracket.
Within the diaphragm housing 114.1, to the left
: hand side of the diaphragm 116.1 (as viewed in the drawing)
there is provided a compression spring 130.1 which urges the
diaphragm to the right hand side of the diaphragm housing.
Accordingly, the spring 130.1 acts in opposition to the
effect of vacuum in the diaphragm housing 114.1 to the left
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hand side of the diaphraym 116.1.
To provide for adjustment of the vacuum level in the
inlet ducting 102 at which the micro-switch 126.1 is actuated, .;
the device 112.1 is provided with two adjustment screws 132.1
and 134.1 which engage respectively with two ~crew-threaded
nuts 136.1 and 138.1 fixed to the diaphragm housing 114.1. The
screw-threaded parts of the screws 132.1 and 134.1 project in
the same direction as that in which the rod 118.1 projec-ts from
the diaphragm housing 114.1. Between the screw threaded end of
each of the screws 132.1 and i.34.1 and a yoke 140.1 which is
fast with the end of the rod 118.1, there extends a coil spring
142.1. Each coil spring 142.1 is connected to the end of the
respective screw by means of a swivel connection 144.1.
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The monitoring device 100 further comprises electrical
circuitry 146. A loudspeaker 148 and an electro-mechanical
counter 150 are connected to the electrical circuitry 146. The
loudspeaker 148 is connected electrically to the circuitry 146
via a removable link 151.
The monitoring device 100 further comprises a first
gating device 152.1, a second gating device 152.2, and a third
gating device 152.3. It also further comprises speed senstive
means 154 having two outputs, namely a first output 156.1 and a
second output 156.2. The speed sensitive means is connected to
the contact breaker points 157 of the engine's distributor in
the case of a spark ignition engine. The operation of the
speed sensitive means 154 is
such that, when the engine speed is above a first predetermined
speed, then an output signal will appear on the first output
156.1, whereas, when the enyine speed is higher and a second,
higher predetermined speed, then an output signal will also
appear on the second output 156.2. Such speed sensitive
means per se are known in the art and any suitable version
providing output signals on two outputs at different speeds
may be utilised.
The Eirst predetermined speed may be about 1000 rpm and
the second predetermined speed may be about 3000 rpm. These
predetermined speeds may be adjustable.
The output 156.1 is connected to one of the inputs of
the gating device 152.1 which has an AND function and the
output 156.2 is connected to one of the inputs of the gating
device 152.2 which also has an AND function. The micro-
switch 126.1 is connected to one of the inputs of the gating
device 152.3 which has an OR function and the micro-switch
126.2 is connected to the other input of -the gating device
152.2. The output of the gating device 152.2 is connected to
the other input of the gating device 152.3 and the output of
the gating device 152.3 is connected to the electrical
circuitry 146. The other input of the gating device 152.1
is connected to a power supply lead 158 for the circuitry
146.
The operation of the monitoring device 100 is as
follows. The adjustment screws 132.1 and 134.1 are adjusted
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so that the micro-switch 126.1 will be actuated at a low
degree of vacuum in the inle-t ducting 102, say, for example,
about 15 kPa (vacuum). The adjustment screws 132.2 ~nd
134.2 are adjusted such that the micro-switch 126.2 will be
actuated at a higher degree of vacuum in -the i.nlet ducting,
say, for example, 40 to 50 kPa (vacuum).
Under good engine operating condi-tions, the degree
of vacuum in the inlet ducting 102 will be high, typically
about 70 kPa (vacuum), resulting in good uti.lisation of fuel
lO drawn in-to the engine via the inlet ducting. Also, the
engine will normally be rotating at a speed which is above
the first predetermined speed so -that an output signal will
appear on the output 156.1, thus enabling the gate 152.1 and
allowing electrical power to be fed from the power supply
lead 158 to the electrical circui-try 146. If the speed of
the engine is above the second predetermined speed of, say,
about 3000 rpm, then the second gate 152.2 will also be
enabled.
When the accelerator pedal of the vehicle is
pressed down, causing the butterfly valve 106 to open further,
the degree of vacuum in the inlet ducting 102 drops, particularly
if the pedal is depressed at an excessive rate or when the
engine is running at a low rotational speed, leading to
uneconomic utilisation of fuel. The low degree of vacuum
will cause the diaphragm 116.1 and the rod 118.1 to move to
the right hand side as viewed in the drawing and the micro-
switch 126.1 to be actuated. The construction of the electrical
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circuitry 146 is such -that when the micro switch 126.1 is
actuated an audible signal in -the form of intermitten-t
bleeping will issue from the loudspeaker 148 and also, if
the micro-switch 126.1 continues to be actuated for more
S than, say, about two bleeps, then a unit count will be
recorded by the counter 150 for each subsequent bleep. The
construction of circuitry operating as described will be
within the capabilities of a man skilled in the art and will
therefore not be described in detail. The intermittent
bleeping may, for example, be provided by a free-running
; multivibrator which is energised when the microswitch 126.1
is actuated. The counter may be driven by the same free-
running multivibrator via a pair of suitably arranged bistable
multivibrators inhibiting operation of the counter for the
first two oscillations of the free-running multivibrator.
If the driver eases off on the accelerator pedal,
or if he changes to a lower gear which will lead to a higher
engine speed for the same road speed, then the degree of
vacuum in the inlet 102 will rise, causing the diaphragm
116.1 and the rod 118.1 to move again to the left hand side
as viewed in the drawing. This will cause the actuating
~ collar 124.1 to disengage from the micro-switch 126.1,
; causing the switch's contacts to open. This in turn will
inhibit further bleeping and counting by the loudspeaker 1~8
and the counter 150. Provided the engine speed is less than
3000 rpm, actuation of the micro-switch 126.2 will not have
any effect, as the gate 152.2 will then be disabled.
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At engine speeds above the second predetermined
speed of 3000 rpm, an output signal will also appear on the
output 156.2, enabling the second gate 152.2. As has been
mentioned above, the second diaphragm device 112.2 has been
adjusted so -that the micro-switch 126.2 will be actuated at
a vacuum level which is higher -than tha-t at which the microswitch
126.1 of the first diaphragm device 112.1 will be actua-ted.
Accordingly, if the engine runs above the second predetermined
speed, then the monitoring device 100 will be more sensitive
to drops in the vacuum level in the inlet ducting 102 and
will cause bleeping and counting via the micro-switch 126.2
of the second diaphragm device 112.2, the gate 152.2 and the
gate 152.3. Thus, the driver of the vehicle will have to be
much more careful with his accelerator pedal when driving at
high speed than will be necessary when he is driving at low
speed.
If the vehicle engine stalls for example, then the
output signals will disappear from both the outputs 156.2
and 156.1. This will disable the gate 152.1, removing the
electrical supply from the electrical circuitry 1~6, and
consequently prevent the issuance of bleeps from the loudspeaker
148 and the making of recordings by the recorder 150. In an
alternative arrangement the speed sensitive means 154 may
be arranged via its output 156.1 to inhibi-t the micro-switch
~26.1 from actuating the electrical circuitry 146, by means
o~ a gating circuit arranged in a similar manner as the
gating circuit 152.2.
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In an alternative arrangemen-t -the two micro-
switches 126.1 and 126.2 may be mounted on the same diaphragm
; device, to be actuated at different vacuum levels. This
will eliminate the need for two separate diaphragm devices
but will require a diaphragm device which is more sophisticated.
The operation of the device of Figure 1 is graphically
illustrated in the graph of Figure 2, being a represen-tation
of the degree of vacuum as a function of engine rotational
speed below which warning signals are issued by the loudspeaker
148 and recordings made by the recorder 150.
In Figure 3 there is shown a graph, similar to the
graph of Figure 2, illustrating the operation of a three-
stage device. In this device no warning signals or recordings
are provided at engine speeds below 1000 rpm, regardless of
the degree of vacuum in the inlet manifold. At speeds
between 1000 rpm and 2300 rpm warning signals or recordings
are provided at vacuum levels of less than 10 kPa, at speeds
between 2300 rpm and 2750 rpm at vacuum levels of less than
20 kPa, and at speeds over 2750 rpm at vacuum levels of less
than 35 kPa.
If desired, an inclined mercury containing capsule
160 (shown in dotted lines) having a pair of electrodes may
be connected in the output of the OR gate 152.3. The capsule
may be arranged such that when the vehicle is inclined at
more than a predetermined (adjustable) angle to the horizontal
in the direction of travel of the vehlcle, then electrical
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contact between the electrodes of the capsule is broken.
This will allow the driver to depress the accelerator pedal
hard when, for example, travelling up a ramp or other steep
incline, without being penalised by the recording of counts
on the recorder 150.
The loudspeaker 148 may be silenced by removing
the link 151. This may be useful when, for example, it is
desired to select drivers for their exonomic driving ability
before employing them. Thus, when a driver solicits for
employment he is given a vehicle and asked to take it for a
test drive along a preselected route. The count on the
counter after completion of the test drive is then evaluated
and only those drivers who return a low count are employed.
The vacuum level at which the switch 126.6 is
actuated (i.e. the level indicated at 162 in the graph of
Figure 2) may be chosen such that when the vehicle is travelling
steadily at a predetermined high speed such as, for example,
90 kph, then the degree of vacuum in the inlet manifold is
just above the line 162. When attempting to increase the
speed of the vehicle beyond the predetermined high speed,
even when this takes place very gradually, the degree of
vacuum will fall below the line 162 and the device will
commence penalising the driver by issuing warning signals
and making recordings. The device is thus operative at low
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speeds to inhibit rapia acceleration o~ the-vehicle whereas,
at hi~h speed it is ope~ative to inhibit speeds in e~cess
o~ a predetermined high speed.
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