Note: Descriptions are shown in the official language in which they were submitted.
A~rO~ATIC CLUTCH CONTROI.SYSTEM
aACKGRCUND OF THE INNEN$ICN
1. Field of the Invention
The present invention relates to a clutch control
system, more particularly to a method and apparatus for an
automatic clutch control system using a microcomputer.
The present invention is advantageously used, for
example, for automobiles having conventional dry-type single~
plate clutches and sliding-mesh-type transmissions.
The automatic clutch control system according to the present
invention can automatically control the clutch moving time,
clutch moving speed, and gear changes under a predetermined
control program stored in a microcomputer, thus allowing easy
driving under all driving conditions.
2. Description of the Prior Art
As is well known, three main types of transmissions are
now in use for clutch control and gear change in automobiles:
manual transmissions, using dry-type single-plate clutches and
sliding-mesh-t~pe transmissions, which are manually operated by
~ a clutch pedal and a change lever; semiautomatic transmissions,
also using dry-type single-plate clutches and sliding-meshrtype
transmissions, which have a gear change mechanism manually
operated by a change lever and a clutch automatically controlled
by a computer; and automatic transmissions, Eor example, using
torque converters and planetary-gear~type auxiliary transmis-
sions, which are automatically controlled by a computer control-
ler.
As also well known, each of these types of transmission
have their own advantages and disadvantages. The main disadvan-
tages oE manual transmissions are troublesome operability, poor
smoothness of change, and susceptibility of efficiency to driving
characteristics o~ individual drivers. The main disadvantage of
7~)70
semiautomatic transmissions is poor smoothness of
change. Finally, t~e main disadvantages oE automatic
transmissions are poor gas mi]eaye, slow response time,
and high cost.
Although technical improvements have been made
alleviating the above disadvan-tages, these improvements
are still not sufficient.
SUMMARY OF THE INVENTION
The primary object of the present invention is to
provide an automatic clutch control system, for use in
automobiles, using a microcomputer and eliminating the
disadvantages in the prior art.
Another object of the present invention is to
provide an automatic clutch control system enabling
highly precise, automatic control of the clutch moving
time and clutch moving speed under various driving
conditions.
Still another object of the present invention is to
provide an automatic clutch control system enabling use
of conventional dry-type single-plate clutches and
sliding-mesh-type transmissions.
In accordance with one embodiment of the present
invention, there is provided an automatic clutch control
apparatus, for use in automobiles which have an
accelerator pedal, a clutch actuated via solenoid
valves, a throttle actuator on an engine and a
transmission having changeable gears, comprising:
accelerator sensing means, coupled to the
accelerator pedal, for sensing accelerator pedal
position;
engine speed sensing means r coupled to the engine,
for sensing engine speed;
clutch stroke sensing means, coupled to the clutch,
for sensing clutch stroke;
automobile speed sensing means, coupled to the
transmission, for sensing automobile speed; and
7~
control means, operatively connected to the
accelerator sensing means, -the engine speed sensing
means, the clutch stroke sensing means and the
automobile speed sensing means, for controlling opening
and closing of the solenoid valves, the gear change of
the transmission and opening and closing of the throttle
actuator, based on predetermined stored data and based
on the position of the accelerator pedal, engine speed,
clutch stroke and automobile speed, for automatic
control of clutch moving time and clutch moving speed.
In accordance with another embodiment of the
present invention, there is provided a method of
automatic clutch control for automobiles, using a
microcomputer and comprising the steps of:
(a) detecting accelerator position by an
accelerator pedal sensor, engine speed by an engine
speed sensor, clutch stroke by a clutch stroke sensor,
and automobile speed by an automobile speed sensor to
generate sensor data;
(b) comparing the sensor data with predetermined
stored data and calculating a clutch moving time and a
clutch moving speed, based on the predetermined stored
data, for various driving conditions;
(c) controlling at least one oE opening and closing
of solenoid valves based on signals generated from flip-
flop circuits via counters activated by the calculating
in step (b), two of -the solenoid valves being series-
connected solenoid valves and a quantity of fluid flow
being controlled by overlapping timing of the least one
of opening and closing of the series-connected solenoid
valves using the microcomputer; and
(d) controlling the clutch moving time and clutch
moving speed by means of a clutch actuator controlled by
the solenoid valves.
` ~21~07~
In accordance with still another embodiment of the
present invention, there is provided a method of
automatic clutch control, for automobiles, using a
microcomputer, comprising the steps of:
(a) detecting accelerator position by an
acclerator pedal sensor, engine speed by an engine
speed sensor, clutch stroke by a clutch s.roke sensor,
and automobile speed by an automobile speed sensor to
aenerate sensor datai
(b) comparing the sensor data with predeter.
mind stored data and calculating a clutch moving time
and a clutch moving speed, based on the predetermined
stored data, for various driving conditions;
(c) controlling at least one of opening and
closing of solenoid valves based on signals generated
fr,om flip-flop circuits via counters activated by said
calculating in step (b); and
(d) controlling the clutch moving time and
speed by means of a clutch actuator controlled by the
solenoid valves, using a predetermined value from
- clutch disengagement to clutch slip and using one of a
set of predetermined values corresponding to a selected
one of parameters of driving conditions irom clutch
slip to clutch engagement.
In yet another embodiment of the present invention,
there is provided a method of automatic clutch control for
automobiles, using a microcomputer and comprising the
steps of:
3a
C
.
~L7Q7~
(a) ae~ecting accelerator position by an
accelerator pedal sensor, engine speed by an engine
speed sensor, clutch stroke by a clutch s.ro~e sensor,
and automobile speed by an automobile speed sensor to
generate sensor data;
(b) comparing the sensor data with predeter-
mined stored data and calculating a clutch moving time
and a clutch moving speed, based on the predetermined
: stored data, for various driving conditions;
(c) controlling at least one of opening and
closing of solenoid valves based on signals generated
from Ilip-flop Cil-CUits via counters activated by said
calculating in step (b); and
(d) controlling the clutch moving speed and
time by means of a clutch actuator controlled by the
solenoid valves, using a constant value from clutch
disengagement to clutch slip and using one of a set of
predetermined values corresponding to a selected one of
parameters of driving conditions from clutch slip to
clutch engagement.
St..i.ll another embodiment of the present inventi~Qn
provides a method of automatie clutch control for
automobiles, using a mieroeomputer and eornprising the
steps of:
,
(a) detecting accelerator position by an
accelerator pedal sensor, engine speed by an engine
speed sensor, clutch stroke by a clutch stroke sensor,
and automobile speed by an autornobile speed sensor to
generate sensor data;
3b
LZ~ 70
(b) cc"paring the sensor data .ith predeter-
mined stored data and calculating a c~utch moving time
znd a clutch movinq speed, based on the predetermined
stored data, for various driving conditions;
(c) controlling at least one of opening and
closing of solenoid valves base~ on signals generated
from flip-flop circuits via counters activated by said
calculating in step (b); and
(d) controlling the clutch moving speed and
time by means of a clutch actuator controlled by the
solenoid valves, using one of a set of pre~etermined
constant values corresponding to a selected one of
parameters of driving conditions from clutch slip to
near clutch engagement and then using a preaetermined
constant speed to clutch engagement.
:
; Yet another embodiment of the present invention provides
a method of automatic clutch control for automobiles, using
a microcomputer and comprising the steps of:
~ (a) detecting accelerator position by an
accelerator pedal sensor, engine speed by an engine
speed sensor, clutch stroke by a clutch stroke sensor,
and automobile speed by an automobile speed sensor to
generate sensor data;
(b) comparing the senso-r data with predeter-
mined stored data and calculating a clutch rno~7ing time
and a clutch moving speed, based on the predeterrnined
stored data, for various driving conditions;
: 3c
~`~' . ' .
~Z~7(1 70
(c) cGntrollir,c at ledst one of o?ening and
closing of solenoid valves based on signals generated
from flip-flop circuits via counters activated by said
calculating in step ~b), two of the solenoid valves
being provided in series in a supply side fluid passage
and another two of the solenoid valves being pl-ovided
in parallel in an e~haust side fluid passage, a auantity
of fluid flow being controlled by overlapping timing of
the at least one of opening and closing of the solenoid
valves of both the supply and e~haust sides using the
microcomputer; and .
(d) controlling the clutch moving time and
clutch moving speed hy means of a c1utch actuator
controlled by the solenoid valves.
Yet another aspect of the invention provides an
automatic clutch control system for an automobile having
an engine with a throttle, an accelerator pedal and a
transmission with a clutch, the system comprising~
I
a throttle actuator, coupled to the
throttle, for adjustment of the throttle;
a clutch actuator, coupled to the
clutch, for controlling engagement and disengagement of
the clutch;
3d
,
C
~2~7(;~7~ ,
solenoid valves, hydraulically connected
to said clutch actuator, for controlling the movement
of said clutch actuator;
clutch stroke sen~ing means, coupled to
said clutch actuator, for sensing clutch stroke;
accelerator sensing means, coupled to
the accelerator pedal, for sensing accelerator position;
engine speed sensing means, coupled to
: the engine, for sensing engine speed;
automobile speed sensing means, coupled
to the transmission, for sensing automobile speed; and
control means, operatively connected to
said clutch stroke sensing means, said accelerator
sensing means, said engine speed sensing means and said
automobile speed sensing means, for controlling opening
and-closi~ng o~ the solenoïd valves, gear change.of the
transmissi.on and adjustments of the throttle actuator,
in dependence upon the conditions sensed by said clutch
stroke, accelerator, engine speed and automobile speed
sensing means, to provide automatic control of clutch
moving time.and clutch moving speed.
.
3e
17~7~
The present invention enables easy driving under all driving
conditions and improved operability and gas mileage compared with
conventional manual, semiautomatic, and Eully automatic transmis-
sions. Moreover, it can be used with dry-type single-plate
elutches and sliding-mesh-type transmissions used in conventional
manual and semiautomatic transmissions.
BRIE~ DESC~IPTICN QF THE DRAWLNGS
In the drawings,
Fig. 1 is a schematie bloek diagram of an automatie eluteh
control system in a conventional semiautomatie transmission;
Fig. 2 is a partial schematie view of a clutch aetuator
shown in Fig. l;
Fig. 3 is a timing ehart of drive current applied to a
solenoid valve (A), the quantity of oil flow through one solenoid
valve (B)" and the quantity of oil flow through another solenoid
valve (C); -~
Fig. 4 is a schematic block diagram of an-automatic clutch
control system according to the present invention;
Fig. 5 is a schematic block diagram of a hydraulic control
circuit including the solenoid valves controlled by the -i
rontroller -hohn in Fig. 4
3f
1~L7(~7~)
Fig. 6 is a schematic block diagram for explaining the
automatic clutch control system shown in Fig. 4;
Fig. 7 to Fig. 9 are graphs for explaining relations between
- clutch stroke and clutch moving time (Fig. 7) and between clutch
stroke and clutch moving speed (Fig. 8 and Fig. 9);
Fig. lO shows timing charts for opening and closing of
valves and the quantity of fluid flow therethrough;
Fig. ll is a basic block diagram of the controller shown in
Fig. 4; and
lOFig. 12 is a flow chart of clutch control procedure
performed in the controller shown in Fig. ll.
DESCRIPTIGN Q~ THE PREE~RRED EMBODIM~NIS
In general, rotation of an automobile engine is transmitted
to the shaft of a transmission mechanism by a dry-type single-
plate clutch. To control the clutch engagement, a hydrauliccontrol actuator is used. The hydraulic control actuator is
constituted by a hydraulic cylinder used to engage and disengage
the clutch and a plurality of solenoid valves used to control the
motion of the hydraulic cylinder. Control of the hydraulic
actuator, i.e., control of the solenoid valves, is effected
mechanically in manual transmissions and electronically in
semiautomatic transmissions.
Before describing the preferred embodiments of the present
invention, an explanation will be given of a conventional clutch
control system for a semiautomatic transmission using a dry-type
single-plate clutch and hydraulic control actuator.
Referring to Fig. l, reference numeral l is an accelerator
pedal, lA an accelerator pedal sensor, 2 an engine, 2A an engine
speed sensor, 3 a throttle actuator, 4 a clutch, 5 a transmis-
sion, 6 a clutch actuator, 6A a clutch stroke sensor, 7 asolenoid valve group, 8 an oil pump, 9 an oil tank, lO a control
unit, and ll an automobile speed sensor.
The control unit lO, constituted by a microcomputer, con-
91 217C~
trols the throttle actuator 3 and the solenoid valve group 7based on a signal transmitte~ from the accelerator pedal sensor
lA, a signal transmitted from the engine speed sensor 2A, a
signal transmitted from the clutch stroke sensor 6A, and a signal
transmitted from the automobile speed sensor 11. The control
unit 10 also feeds back the stroke signal transmitted from the
clutch stroke sensor 6A to control the opening of the solenoid
valve group 7 for engagement, slip, or disengagement of the
clutch based on the clutch moving speed, as defined by clutch
engagement, clutch slip, clutch disengagement, change in engine
speed, automobile speed, and other driving conditions.
In other clutch control systems used for semiautomatic
transmission, the system feeds back a stroke signal transmitted
from a clutch stroke sensor, engine speed sensor, and automobile
speed sensor to control the duty ratio (ratio of opening and
closing time of valve) of solenoid valves by a control unit so as
to obtain both a clutch moving speed and clutch moving time
defined by engine speed, automobile speed, and other driving
conditions.
However, it is difficult to obtain the desired clutch moving
speed and clutch moving time by controlling the opening or
closing of the solenoid valves because it is necessary to finely
control the duty ratio of the opening or closing of the valves,
which necessitates complex valve control.
The above problems will be explained in detail hereinafter
with respect to Fig. 2 and Fig. 3. Referring to Fig. 2, as
mentioned above, the hydraulic control actuator is constituted by
a clutch actuator, i.e., an oil cylinder 6, and a plurality of
solenoid valves (Vl to V3). A piston 6B equipped with a piston
rod 6C is provided in the oil cylinder 6. The solenoid valve Vl
is provided for exhaust in a small diameter fluid passage, and
the solenoid valve V2 is provided for exhaust in a large diameter
fluid passage. The solenoid valve V3 is provided for supply.
~L'7~7~
Although only two exhaust solenoid valves Vl and V2 are
shown in the drawing, generally a plurality of fluid passages
having the same diameters are provided in the actuator and each
fluid passage is controlled by a solenoid valve. In the case
shown in the drawing, the solenoid valve V2 is used for coarse
control of the oil flow, and solenoid valve Vl for fine control
of the oil flow.
Referring to Fig. 3, when a drive cnrrent having a pulse
waveform as shown in ~A) is applied to the solenoid valves Vl and
V2, the oil flow through the solenoid valve Vl in the small
diameter fluid passage is shown by (B), and the oil flow through
the solenoid valve V2 in the large diameter fluid passage is
shown by (C).
The oil flows through the solenoid valves Vl and V2 are
constant so long as the pulse waveform of the drive current is
the same, i.e., has the same pulse width. The oil flow, however,
changes when the pulse width becomes smaller or along with
increasingly smaller diameters of fluid passages, in order to
achieve finer control, whereby the control of the hydraulic
actuator becomes unstable. Acco~dingly, it is difficult to
obtain precise control of opening or closing of solenoid valves
so as to obtain the desired clutch moving speed and clutch moving
time~
An automatic clutch control system according to the present
invention will now be explained in detail. As explained above,
the automatic clutch control system according to the present
invention can be used with conventional dry-type single-plate
clutches and sliding-mesh-type transmissions. In the present
invention, the change lever used in semiautomatic transmissions
is eliminated and a transmission changer (drive mechanism) added
instead. These clutch and drive mechanisms are controlled by a
microcomputer controller~ Accordingly, the clutch control system
according to the present invention is a fully automatic
~Z1707V
.
transmission using a conventional clutch and transmission.
~ eferring to Fig. ~, the automatic clutch control system is
constituted by the same comFonents as shown in Fig. 1, except for
a controller 100, a solenoid valve group 70, and a changer 12.
Components the same as in Fig. 1 are indicated by the same
reference numerals.
Referring to Fig. 5, the clutch 4 is constituted by a clutch
pressure plate 4A, clutch disk 4B, diaphragm spring qC, clutch
release bearing 4D, clutch release lever 4E, clutch shaft 4F, and
lever 4G. Reference numeral 2B is an engine flywheel; 701, 701',
702, and 703 solenoid valves in the solenoid qroup 70; B a
battery; SW a power switch associated with an ignition switch;
and AC an accumulator.
The clutch 4 is controlled by controlling the opening or
15 closing of the solenoid valves 701, 701', 702, and 703 using the
controller 100. The controller 100 consists of a microcomputer
storing a program with respect to driving conditions. When the
solenoid valves 701 and 701', for example, are actuated by the
controller 100, pressurized fluid is supplied to the oil cylinder
6 from the oil pump 8. The piston 5B of the oil cylinder 6 is
thus moved toward the right as indicated by the arrow line to
disengage the clutch disk 4B. When the solenoid valves 702 and
703 are actuated by the controller 100, the pressurized fluid is
exhausted from the oil cylinder 6. The piston 6B thus moves in
the reverse direction due to the action of a return spring (not
shown) to re-engage the clutch disk ~B.
This control of clutch engagcment and disengagement ~ill be
explained in more detail hereinafter with respect to Figs. 6, 7,
8, 9, and 10.
The controller 100 stores various parameters, for example, a
to d shown in Figs. 7 to 9, defining the relation between the
clutch stroke and clutch moving time or between the clutch stroke
and clutch moving speed based on various driving conditionst
9LZ~7~7~
such as upward or downward slopes, flat roads, and stopping. The
controller 100 uses these parameters a to d and the signal
transmitted from the clutch stroke sensor 6A, for example, a
potentiometer, to calculate the desireable clutch moving speed
and clutch moving time corresponding to the clutch stroke S and
controls the solenoid valve group 70 based on the results of its
calculations.
The control modes will be explained in more detail with
respect to Figs. 7 to 9. Referring to Fig. 7, the ordinate
indicates the clutch stroke (S) and the abscissa indicates the
clutch moving time (T). The lines I, II, and III indicate clutch
engagement (clutch on), clutch slip (half clutch), and clutch
disengagement (clutch off). As is obvious from the graph, the
clutch moving time is controlled to a predetermined gradually
increasing value in the clutch operation from line III to line II
and controlled to one of a set of predetermined gradually
increasing values corresponding to a selected one of the driving
condition parameters a to d in the clutch operation from line II
to line I.
In Figs. 8 and 9, the ordinates indicate the clutch stroke
(S) and the abscissas indicate the clutch moving speed (V). In
the control modes of both Figs. 8 and 9, the clutch moving speed
is controlled to a constant value in the clutch operation from
line III to line II. In Fig. 8, the clutch moving speed is
controlled to one of a set of predetermined gradually decreasing
values corresponding to a selected one of the driving condition
parameters a to d in the clutch operation from line II to line I.
In Fig. 9, the clutch moving speed is controlled to one of a set
of predetermined constant values in the clutch operation from
line II to near line I and to a predctermined constant value to
line I.
Next, fine control of the solenoid valves 701, 701', 702,
and 703 shown in Fig. 5 and Fig. 6 will be explained in reference
-~-` lZ~ 7~
to Fig. 10 (A) to (D).
Referring to Fig. 10, as mentioned above, the open ("on")
and close (noff") timings of each solenoid valve 701, 701', 702,
- and 703 are controlled by the controller 100. The "on" and "off"
timings can be independently selected by the controller 100.
Generally, there is a time delay between the "on" and "off"
timings in different valves. As a result, the quantity of oil
flow through the vaives changes gradually at the leading edges
and trailing edges of the waveforms shown in Fig. 10.
In the case of two valves, when both valves are turned on
nearly simultaneously by drive currents il and i2 and are left on
for a long time, the quantity of oil flow Q is indicated by the
hatched area in Fig~ 10 (A). When both valves are simultaneously
turned on for a short time, the quantity of oil flow Q is as
shown in Fig. 10 (B). When the upstream valve is changed from
~onn to "off" and the downstream valve is changed from "off" to
"on~ the quantity of oil flow is as shown in Fiq. 10 (C).
As is obvious from the waveform shown in Fig. 10 (D), the
overlapping of the "on~ and "off" timing of the valves affects
the quantity of oil flow.
The ~ethod for controlling the quantity of oil flow accord-
ing to the present invention is particularly advantageous when
the solenoid valves 701, 701', 702, and 703 are controlled as
shown in Figs. 10 (C) and (D). Now, in the embodiment shown, the
solenoid valves 701 and 701' are provided in series in the supply
sidc fluid passage, while the solenoid valves 702 and 703 are
provided in parallel in the exhaust side fluid passage. In
conventional systems using a single solenoid valve in the supply
side, the solenoid valve has not been able to operate fast enough
in accordance with a rapid succession of ~on" and "off"
instructions. As a result, conventionally, the quantity of oil
flow through the valves during "on" and "off" timing has been
unstable.
However, according to the present invention, "on" and
"off" control of valves can be independently performed by the
controller 100. Consequently, it is possible to control the
solenoid valves 701, 701', 702, and 703 to operate at exactly
the right timings. A stable flow of oil is possible even with
an extremely small overlap of time in "on" timing.
Consequently, since the quantity of oil flow through each
valve can be finely controlled by the microcomputer, the clutch
moving speed and the clutch moving time can be controlled for
various driving conditions.
Referring to Fig. 11, the controller 100 is mainly consti-
tuted by analog-digital converters ADl to AD4, an address modi-
fier AMO, memories Ml to M4, a comparator and calculator CAL,
counters CNTl to CNT4, and flip-flop circuits FFl to FF4. The
address modifier AMO, comparator and calculator CAL, and coun-
ters CNT are incorporated in a central processing unit CPU.
An analog output detected by, for example, the accelerator
pedal sensor lA is applied to the analog-digital converter ADl.
An analog output detected by, for example, the clutch stroke
sensor 6A is applied to the analog digital converter AD2. The
digital outputs from the analog-digital converters ADl and AD2
are applied to the memories Ml and M2, respectively, via the
address modifier AMO. The digital outputs designate addresses
in the memories (tables) Ml and M2.
Data read out from the tables is supplied to the compara-
tor and calculator CAL and appropriately processed. In the mem-
ory Ml, the resultant data and the pulse G are applied to the
counter CNTl and the flip-flop FFl for presetting the counter
CNTl and for setting the flip-flop FFl. When the flip-flop FFl
is set, the transistor TRl turns on and the solenoid valve 701
is activated. The counter CNTl sequentially counts down from
the preset number using the periodically input pulse T and re-
sets the flip-flop FFl when reaching zero, based on a zero de-
tecting signal generating from the counter CNTl itself.
B
1'7C~7~
The output "set signal~ of the ~lip-flop FF1 is applied to
a base of a transistor TRl, as explained above, the transistor
turns on and the solenoid valve 701 is activated. The flip-
flop FFl is rese~ based on the zero detecting signal, the tran-
sistor TR1 turns off, and the solenoid valve 701 is deacti-
vated. Accordingly, the larger the preset number of the coun-
ter CNT1, the longer the activating time (on time) of the sole-
noid 701. If the gate value which controls output of the mem-
ory M1 is stored in another table, for example, memory M2, the
clutch moving speed and clutch moving time can be controlled as
shown in Figs. 7 to 9.
Referring to Fig. 12, the signals from each sensor, i.e.,
the accelerator pedal sensor lA, the engine speed sensor 2A,
the clutch stroke sensor 6A, and the automobile speed sensor
11, are first applied to the analog-digital converters at step
l. These analog signals are converted to digital signals at
step 2~ The digital signals transmitted from the analog-
digital converters designate addresses in the tables at step 3.
The stored data is read out from the tables and applied to the
comparator and calculator CAL at step 4. The comparator and
calculator CAL compares the read out data with prestored data
; of driving conditions a, b, c, and d and calculates dif-
ferentials for obtaining clutch moving time and clutch moving
speed based on commands transmitted from the central processing
unit CPU at steps 5 and 6. The resultant data is applied to
the counters, which se~uentially count down from preset numbers
based on the periodically input pulses at step 7. The flip-
flop circuits are reset by other periodically input pulses when
the counts become zero at step 8. The outputs of the flip-flop
circuits are applied to the bases of the transistors and the
transistors turn on. The solenoid valves are activated by the
current flowing through the transistors at step 9. Consequent-
ly, the cylinder stroke is controlled by the "on" or "off" tim-
ing of each valve at step lO. Therefore, the clutch stroke can
be suitably controlled for all driving conditions.
r~
D
