Engine Automatic Control System For Vehicles Including Plural Clutch Actuated Switches

Abstract

An engine automatic control system for an internal combustion engine of a vehicle is provided which comprises an engine control circuit for controlling the operative condition of the engine in accordance with the driving condition of the vehicle, a starter energizing circuit for selectively connecting an electric source with a starter for the engine, a starter cut-off circuit able to respond to the start of rotation of the engine to cut off current supply to the starter, a first clutch switch coupled with the engine control circuit to be closed by the initial depression of a clutch pedal of the vehicle to cause the half engagement of clutch means of the vehicle so as to activate the engine control circuit and complete the operative condition of the engine, a second clutch switch coupled with the starter energizing circuit to be closed by the final depression of the clutch pedal to cause the full disengagement of the clutch means so as to activate said starter energizing circuit, and a speed senser coupled with the engine control circuit for detecting the moving of the vehicle to maintain the operative condition of the engine while the vehicle is moving.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an automatic control system for an engine of vehicles, and more particularly to an improvement of the engine control system such as disclosed in U.S. Pat. No. 3,731,108 dated May 1st, 1973, German Pat. No. 2,158,095 dated Sept. 6th, 1973 and French Pat. No. 7,139,281 dated July 10th, 1972.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an engine automatic control system, wherein the engine starter is energized only upon the full disengagement of the clutch means of a vehicle so that no excess load is given to the starter thereby to save electric energy of the electric source of the vehicle.

Another object of the present invention is to provide an engine automatic control system, having the above-mentioned characteristics, wherein the engine rotation will be maintained even when the vehicle is arrested to enable the next movement immediately after the complete stop of the vehicle at such occasions that the vehicle will make its left or right turn, and that the vehicle makes its reverse movement and emergent sudden stop.

A further object of the present invention is to provide an engine automatic control system, having the above-mentioned characteristics, wherein the control system is in inoperative condition when electric accessories of the vehicle such as head lamps are energized so as to save electrical energy of the electric source.

A still further object of the present invention is to provide an engine automatic control system, having the above-mentioned characteristics, wherein the control system does not work to stop the engine operation when the vehicle is arrested on a slant place.

A still another object of the present invention is to provide an engine automatic control system, having the above-mentioned characteristics, wherein the control system does not work to stop the engine operation until cooling water for the engine is chilled under a predetermined high temperature.

BRIEF DESCRIPTION OF THE DRAWING

The above mentioned and further objects and features of the presennt invention will become clearer from the following description in reference with the accompanying drawing, which depicts a preferred embodiment of an engine automatic control system in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Now referring to the drawing, described in detail is an engine automatic control system in accordance with the present invention, which includes an ignition switch 2, an ignition circuit 3 connected to the IG terminal of the ignition switch 2 and an engine starter 4 connected to the ST terminal of the ignition switch 2 to selectively connect the starter 4 with an electric source 1 in the form of a vehicle battery. The mentioned constructional portions are of well-known type and heretofore generally in use for motor-driven vehicles.

The engine automatic control system importantly comprises an engine control circuit 100 connected to the electric source 1 through a transfer contact 11 of a self-holding relay 10 and the ignition switch 2, thereby to connect the electric source 1 with the ignition circuit 3 in response to the depression of a clutch pedal and/or an accelerator pedal of a vehicle, to maintain the ignition circuit 3 conductive while the vehicle is moving and to render the ignition circuit 3 nonconductive after the vehicle has been brought to rest. The engine control system further comprises a starter energizing circuit 200 to connect the electric source 1 to the engine starter 4 in response to the depression of the clutch pedal and a starter cut-off circuit 300 to cut off current supply to the starter 4 in response to the start of engine rotation caused by the starter 4. The starter energizing circuit 200 and the starter cut-off circuit 300 are connected to the electric source 1 by way of the transfer contact 11 of the relay 10 and the ignition switch 2. The self-holding relay 10 has the transfer contact 11 to normally engage with an input terminal 12 of the ignition circuit 3. A coil of the relay 10 is grounded at its one end and connected at its other end to the electric source 1 through a manual set switch MS and the ignition switch 2 to be energized by the closure of the set switch MS. The coil of the relay 10 is further connected at its other end to the input terminal 13 of the engine automatic control system of the present invention through a manual release switch RS.

The engine control circuit 100 is provided with an ignition relay 101 having a normally open contact to be closed by the conduction of a transistor 102. The transistor 102 is connected at its collector to the relay 101 and grounded at its emitter. The base of the transistor 102 is connected to an output terminal of a conventional schmitt circuit substantially including transistors 103 and 104 and connected to a lighting switch 21, a reverse-drive switch 22 and a thermosenser 23 through diodes 118, 119 and 120 respectively.

The lighting switch 21 is a normally open switch connected at its one end to the terminal +B of the electric source 1 to maintain the conduction of the transistor 102 when head lamps of the vehicle are lit. The reverse-drive switch 22 in the form of a normally open switch connects the electric source 1 to the base of the transistor 102 across the diode 119 to energize the relay 101 when the vehicle is moved backward. Furthermore, the thermosenser 23 is a normally closed switch grounded at one end thereof to interrupt current supply to the base of the transistor 102 from the electric source 1 by way of a resistor 121 and the diode 120. Thus, the thermosenser 23 is opened to cause the conduction of the transistor 102 when the temperature of the engine cooling water becomes over a predetermined high value to cause the overheat of the engine or under a predetermined low value to stop the engine.

The transistor 104 of the schmitt circuit is connected at its base by way of a resistor 105 to an output 107 of a D-A converter including condensers 106 and 110, a diode 108 and a resistor 111. The condenser 110 is connected at its one end to a speed senser 25 and connected at its other end to the anode of the diode 108 so as to block current supply to the base of the transistor 104 from the electric source 1 during the conduction of a transistor 116 which is normally conductive while the control system is in the energized state. The speed senser 25 is coupled to a permanent magnet provided on a rotating portion of the vehicle power train. The condenser 106 is connected to the junction 107 between the resistor 105 and the diode 108 at one end thereof and grounded at its other end to convert pulse signals exerted thereon from the speed senser 25 into analog signals. Further, the condenser 106 and the resistor 105 form a time-constant circuit to maintain the energization of the relay 101 in a predetermined period of time after the vehicle is arrested. At the junction 107, connected is a resistor 113 in series with a turn signal switch 24 of a normally open type which is connected to the electric source 1 to maintain the conduction of the transistor 102 by means of the operation of the schmitt circuit while a conventional flasher device of the vehicle is activated.

The engine control circuit 100 further comprises the transistor 116 to connect the electric source 1 with the ignition circuit 3 by way of the energization of the relay 101 in response to the depression of the clutch pedal when the vehicle is arrested. The transistor 116 is connected at its collector to the junction 109 between the diode 108 and the condenser 110 through a diode 114 and to the electric source 1 by way of a resistor 115. The base of the transistor 116 is connected to the electric source 1 through a resistor 117 and in series with an accelerator switch 26 which is connected in parallel with a first clutch switch 27 and a slope senser 28, the switches 26 and 27 and the slope senser 28 being normally opened and grounded at one end thereof respectively. The first clutch switch 27 is designed to be closed by the clutch pedal when a frictional clutch engagement mechanism for the vehicle is conditioned to its half engagement.

The starter energizing circuit 200 comprises a starter relay 201 having a normally open contact to be closed by the conduction of a transistor 202. The transistor 202 is connected at its collector to the relay 201 and grounded at its emitter. The base of the transistor 202 is connected to the electric source 1 through a resistor 203, the transfer contact 11 and the ignition switch 2 and further connected to the collector of a transistor 204. The transistor 204 is connected at its base to the electric source 1 through a diode 205, a resistor 206, the transfer contact 11 and the ignition switch 2 so as to normally deactivate the transistor 202. The transistor 204 is further connected at its base to a second clutch switch 29 through the diode 205 and grounded at its emitter. The second clutch switch 29 is designed to be closed by the clutch pedal when the frictional clutch engagement mechanism is conditioned to its full disengagement. Thus, the second clutch switch 29 acts to cause the non-conduction of the transistor 204 by its closure so as to activate the engine starter 4 by way of the transistor 202 and the relay 201 during the full disengagement of the clutch mechanism.

The starter cut-off circuit 300 includes a second schmitt circuit which comprises transistors 301 and 302. The transistor 301 is connected at its collector to the base of the transistor 204 through a resistor, and to the electric source 1 through a resistor 303 and the transfer contact 11. The transistor 302 is connected at its collector to the electric source 1 through a resistor 304 and further connected at its base to an alternator 305 driven by the vehicle engine by way of resistors.

The operation of the system of the present invention as described above is well explained hereinafter. While the vehicle is arrested with both of the ignition and manual set switches 2 and MS turned on, that is, the B terminal is in connection with the IG terminal within the ignition switch 2, the self-holding relay 10 is energized to connect the electric source 1 to the engine control system by way of the transfer contact 11. In this condition, depression of the clutch pedal closes the first clutch switch 27 to ground the base of the transistor 116 and sequentially closes the second clutch switch 29 to make the transistor 204 non-conductive. The transistor 116 becomes non-conductive to cause the charge of the condenser 106 by the electric source 1 through the diodes 108 and 114 and the resistor 115 and to make the transistor 102 conductive by means of the inversion of the first schmitt circuit activated by the charged voltage of the condenser 106 in a short period of time. This causes the energization of the ignition relay 101 to connect the electric source 1 to the ignition circuit 3 through the relay 101. Simultaneously, the non-conduction of the transistor 204 causes the conduction of the transistor 202 to energize the starter relay 201 so as to operate the starter 4. Then, the starter 4 drives the engine of the vehicle. As the engine rotates, voltage appears within the alternator 305 and the second schmitt circuit operates to make the transistor 204 conductive and to condition the transistor 202 to its non-conductive state. Thus, the starter relay 201 is deenergized by the non-conduction of the transistor 202 to cut off current supply to the starter 4.

In starting the vehicle, the accelerator pedal is gradually depressed to close the accelerator switch 26 and the clutch pedal is gradually released to open the first and second clutch switches 27 and 29. In this instance, the transistor 116 kept non-conductive maintains the charge of the condenser 106 to keep the ignition relay 101 operative. When the vehicle runs, even if the transistor 116 is turned to be conductive by opening of the accelerator switch 26, the current supply to the ignition circuit 3 given by the energization of the ignition relay 101 is maintained by the output of the D-A converter including the condenser 106 driven by the speed signals from the speed senser 25.

When the vehicle is arrested on a flat ground, the accelerator pedal being released and the clutch and brake pedals being actuated, the slope senser 28 is kept open and the first clutch switch 27 is closed to make the transistor 116 non-conductive. This maintains current supply to the ignition circuit 3 by means of the energization of the ignition relay 101 which is caused by the operation of the first schmitt circuit connected to the electric source 1 by way of the diodes 108 and 114 and the resistor 115. At the same time, current supply to the starter 4 is blocked by the deenergization of the starter relay 201 which is caused by the operation of the second schmitt circuit applied the alternator voltage therein. In this condition, when the clutch pedal is released to open the first and second clutch switches 27 and 29, the transmisstion of the vehicle being conditioned to its neutral state, the transistor 116 is turned to be conductive and the ignition relay 101 is deenergized after the predetermined period of time defined by the time constant of the resistor 105 and the condenser 106. Consequently, the current supply to the ignition circuit 3 is blocked to automatically stop the engine rotation. In the case that the vehicle is arrested on a slant ground, on a slope, etc., the slope senser 28 is closed to keep the non-conduction of the transistor 116 regardlessly of the on-off condition of the first clutch switch 27. Thus, the current supply to the ignition circuit 3 is maintained by means of the energization of the ignition relay 101 which is caused by the operation of the first schmitt circuit connected to the electric source 1 by way of the diodes 108 and 114 and the resistor 115. As the result, the engine keeps running to prevent the vehicle from moving back on the slope when the vehicle starts running.

In the case the temperature of engine cooling water stays higher than the predetermined high value or lower than the predetermined low value during the arresting of the vehicle, the thermosenser 23 becomes off to directly cause the conduction of the transistor 102 due to the current supply applied from the electric source 1 through the resistor 121 and the diode 120. Then, the ignition relay 101 maintains its energization to keep the current supply to the ignition circuit 3 independently of the operation of the first clutch switch 27.

In turning the vehicle, the turn signal switch 24 is closed in response to the actuation of the flasher device of the vehicle to directly connect the electric source 1 to the base of the transistor 104 of the first schmitt circuit through the resistors 113 and 105 independently of the operation of the first clutch switch 27. This operates the first schmitt circuit to keep the energization of the ignition relay 101 by way of the conduction of the transistor 102, and the current supply to the ignition circuit 3 is maintained to keep the engine rotation. This means that instantly starting the vehicle soon after the stop is possible since the engine does not stop and the rotation of the engine can smoothly be accelerated.

When the rearward drive power train of the vehicle is completed, the reverse-drive switch 22 is closed in response to the shifting operation of a transmission of the vehicle to directly connect the electric source 1 to the base of the transistor 102 through the diode 119. The conduction of the transistor 102 maintains the energization of the ignition relay 101 to keep the current supply to the ignition circuit 3. This condition can be realized independently of the operation of the first clutch switch 27.

In the case the electric energy of the electric source 1 in the form of the vehicle battery is supplied to electric accessories such as head lamps, tail lamps and the like, the lighting switch 21 is closed in response to lighting of the above electric accessories to directly connect the electric source 1 to the base of the transistor 102 through the diodoe 118. The conduction of the transistor 102 maintains the energization of the ignition relay 101 to keep the current supply of the ignition circuit 3. This condition can be realized independently of the operation of the first clutch switch 27.

Although a certain specific embodiment of the present invention has been shown and described, it is obvious that many modifications and variations thereof are possible in light of these teachings. It is to be understood therefore that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.

Claims

1. An automatic control system for an internal combustion engine of a vehicle comprising:

an engine control circuit for controlling the operative condition of the engine in accordance with the driving condition of the vehicle;

a starter energizing circuit for selectively connecting an electric source with a starter for the engine;

a starter cut-off circuit able to respond to the start of rotation of the engine caused by the starter to cut off current supply to the starter;

a first responsive means coupled with said engine control circuit to be actuated by the initial depression of a clutch pedal of the vehicle to cause the half engagement of clutch means of the vehicle so as to activate said engine control circuit and complete the operative condition of the engine;

a second responsive means coupled with said starter energizing circuit to be actuated by the final depression of the clutch pedal to cause the full disengagement of the clutch means so as to activate said starter energizing circuit; and

a third responsive means coupled with said engine control circuit for detecting the moving of the vehicle to maintain the operative condition of the engine while the vehicle is moving;

whereby when the vehicle has been brought to rest, the inoperative condition of said first and second responsive means act to cause the deactivation of said engine control circuit and automatically render the engine inoperative and the actuation of said first and second responsive means act to automatically rotate the starter of the engine by means of the activation of said starter energizing circuit under the full

2. The control system as set forth in claim 1, further comprising a fourth responsive means to maintain the operative condition of the engine regardlessly of the inoperative condition of said first and second

3. The control system as set forth in claim 2, wherein said fourth responsive means includes a turn signal switch to be closed by the operation of a flasher device for the vehicle to maintain the activation

4. The control system as set forth in claim 2, wherein said fourth responsive means includes a reverse-drive switch to be closed upon the completion of the reverse drive power train of the vehicle to maintain the

5. The control system as set forth in claim 2, wherein said fourth responsive means includes a lighting switch to be closed by the energization of electrically powered accessories of the vehicle to

6. The control system as set forth in claim 1, wherein said system comprises a thermo-sensing means for detecting the temperature of engine cooling water so that said sensing means activates said engine control circuit to maintain the operative condition of the engine when the vehicle

7. The control system as set forth in claim 1, wherein said system comprises slope sensing means for detecting the gradient of places where the vehicle is arrested so that said sensing means activates said engine control circuit to maintain the operative condition of the engine when the

8. The control system as set forth in claim 1, further comprising a fifth responsive means for activating said engine control circuit to maintain the operative condition of the engine regardlessly of the inoperative

9. The control system as set forth in claim 8, wherein said fifth responsive means is an accelerator switch coupled with said engine control circuit to be closed by the depression of an accelerator pedal of the vehicle so as to maintain the activation of said engine control circuit.