Patent Publication Number: US-6218743-B1

Title: Starting apparatus for vehicle having electronically controlled clutch

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to a starting apparatus in a vehicle for engaging and disengaging a clutch by an actuator which is electronically controlled in accordance with output signal from various detection means which detect the driving states. 
     SUMMARY OF THE INVENTION 
     In a vehicle having the above-described automatic control unit for automatically controlling the clutch to engage or disengage in accordance with the driving state of the vehicle based on the output signal from the above-described various state detecting means, it is an object of the present invention to provide a starting apparatus capable of safely starting the engine only under a constant condition, capable of starting the engine even when the control unit is repaired, and capable of finding the trouble of the related detecting means, in view of the automating tendency of the vehicle clutch. 
     To achieve the above object, there is provided a starting apparatus for a vehicle having an electronically controlled clutch in which the clutch is engaged or disengaged by an electronically controlled actuator in accordance with output signals from various detecting means for detecting driving state, wherein a starter cut relay having normally-closed contacts is connected to an output terminal of an electronic control unit, one of the contacts of the relay is connected to one end of a relay coil of a starter relay connected at the other end of said relay coil to a power source through a key switch, and the other contact of the cut relay is connected to a non-grounded side contact of a neutral relay connected to the power source in series together with a neutral switch. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects and features of the invention will be understood from the following detailed description of a preferred embodiment thereof, taken with the accompanying drawings, in which: 
     FIG. 1 is one example of a circuit diagram of a starting apparatus of a vehicle having an electronic control clutch of the present invention; 
     FIG. 2 is a view showing a control system in a vehicle to which the starting apparatus for the vehicle having an electronic control clutch of the present invention should be applied; and 
     FIG. 3 is a view entirely showing one example of an automatic clutch apparatus for a vehicle. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     In accordance with the present invention, a vehicle includes a transmission which is manually operated, with; 
     In a vehicle, a transmission being manually operated, and only the clutch is basically engaged or disengaged automatically in accordance with the state of the transmission and the driving state, and with the clutch also being designed such that the clutch can be operated manually when the driver desires or when the clutch can not be operated automatically. FIG. 3 shows such an automatic clutch apparatus for a vehicle. 
     That is, in this apparatus, an intermediate cylinder  8  is disposed between a slave cylinder  4  connected to one end of a clutch release fork  3 . The fork  3  is turned around a fulcrum “a” by cylinder  4 , as illustrated in FIG.  3  and the other end of the fork pushes a release bearing  2  of a friction clutch  1  and a master cylinder  7  having an oil tank  6  is operated by pedaling a clutch pedal  5 . A left end and a right end of the intermediate cylinder  8  are connected to the slave cylinder  4  and the master cylinder  7  through pipes  9  and  10 , respectively. In the intermediate cylinder  8 , a first piston  11 , provided at its opposite ends with projections, is formed at the side of the master cylinder  7 , and a second piston  12  having the same shape as that of the first piston  11  and longer than the first piston  11  is formed at the side of the slave cylinder  4 . In the intermediate cylinder  8 , a right chamber  8   a  and a left chamber  8   b  are defined by the first and second pistons  11  and  12  respectively. The intermediate cylinder  8  has two openings which are respectively through a check valve  15  connected, through pipes  13  and  14  respectively, to an oil feed port  17   a  of a hydraulic pump  17  which is rotated by a motor  16  and through a relief valve  8  to an intake port  17   b.  Further, solenoid valves  19  and  19 ′ bypassing the pipe  14  are connected, through a pipe  20 , to an oil tank  21  which is also connected to the left chamber  8   b  of the intermediate cylinder  8 . The reference number  22  represents clutch stroke detecting means for detecting the movement of the clutch release fork  3 . 
     A clutch hydraulic actuator  23  comprises the intermediate cylinder  8  having the oil tank  21 , the hydraulic pump  17  rotated by the motor  16 , the check valve  15 , the relief valve  18 , the solenoid valves  19 ,  19 ′ and the pipes  13 ,  14  and  20 . 
     FIG. 2 shows a control system for an automatic clutch apparatus for the vehicle shown in FIG. 3 (and FIG.  1 ). In FIG. 2, the reference number  24  represents a clutch automatic control unit. Connected to the input side of the clutch automatic control unit  24  are the clutch stroke detecting means  22 , engine revolution number detecting means  25  for detecting the revolution number of an engine ENG, vehicle speed detecting means  28  such as a transmission revolution sensor  26  and a vehicle speed sensor  27  for detecting a vehicle speed, gearshift position detecting means  29  for detecting the gearshift position, a neutral switch  29 ′ for detecting the neutral position, shift knob grasp detecting means  31  for sensing the grasp of a shift knob  30  to detect a will or an action of gear shifting, a clutch automating switch  32  for detecting a will to automate the clutch, a clutch pedal switch  33  having detecting means for detecting the pedaling operation used for switching from automatic operation to manual operation, brake detecting means  35  mounted to a brake pedal  34  for detecting the braking operation, an accelerator switch  36  for detecting the pedaling operation and its pedaling amount, accelerator opening degree detecting means  36 ′ and, various detecting means such as parking brake detecting means  37  for detecting the operation of the parking brake. In addition to these, means  38  for detecting the opening of a door is also connected to the input side of the unit  24 . 
     On the other hand, the output side of the clutch automatic control unit  24  is connected to the clutch hydraulic actuator  23 , an indicator lamp  39  for displaying various states, a warning mechanism  40  such as a buzzer, and a controller (not shown) of the engine. 
     FIG. 3 shows a state in which hydraulic pressure is applied to the slave cylinder  4  and the friction clutch  1  is engaged. From this state, if the gearshift is brought into neutral and the engine is started, and the automating switch  32  is turned ON (automatic) and the shift knob  30  is grasped to turn the shift knob grasp detecting means  31  ON to change the gear, the hydraulic pump  17  is rotated by the motor  16  to increase the hydraulic pressure, and the check valve  15  is opened to send the oil into the intermediate chamber  8   c  of the intermediate cylinder  8  through the pipe  13 . With this operation, the second piston  12  is pushed toward the left chamber  8   b  and the oil in the left chamber  8   b  is sent to the slave cylinder  4  through the pipe  9 . Therefore, the clutch release fork  3  is turned in the counterclockwise direction around the fulcrum a through the piston  4   a,  thereby pushing the release bearing  2  leftward to disengage the friction clutch  1 . If the clutch stroke detecting means  22  detects that the piston  4   a  moves through a predetermined stroke, the power source to the motor  16  is cut to stop the rotation of the hydraulic pump  17 . 
     In the process for disengaging the clutch  1  from its engaged state, among the oil sent from the hydraulic pump  16  to the intermediate chamber  8   c  of the intermediate cylinder  8 , the excessive amount of oil pushing the second piston  12  is sent to the oil tank  21  through the solenoid valves  19  and  19 ′ and through the pipe  20 . 
     After the power source to the motor  16  is cut to stop the hydraulic pump  17 , if the solenoid valves  19  and  19 ′ are opened while controlling the valves so as to adjust the returning speed of the oil, the oil in the slave cylinder  4  moves in the pipe  9  and enters into the left chamber of the intermediate cylinder  8  by the returning movement of the piston  4   a  leftward in FIG.  3  through the clutch release fork  3 , so that the second piston  12  which was located at left side is pushed to the right side position in FIG.  3 . Therefore, the oil in the intermediate chamber  8   c  is returned from the pipe  14  to the oil tank  21  through the solenoid valves  19  and  19 ′ and through the pipe  20 . At that time, the solenoid valves  19  and  19 ′ are, e.g., duty-controlled, so that the friction clutch  1  is engaged while controlling the returning speed of the second piston  12 . 
     In FIG. 3, if the clutch pedal  5  is depressed, the oil in the master cylinder  7  is pushed leftward as viewed in FIG. 3, and is introduced into the right chamber  8   a  of the intermediate cylinder  8  through the pipe  10 , thereby pushing the first piston  11 . Therefore, the first piston  11  pushes, through its projections, the second piston  12  leftward as viewed in FIG. 3, the second piston  12  sends the oil in the left chamber  8   b  into the slave cylinder  4 , thereby turning the clutch release fork  3  around the fulcrum a in the counterclockwise direction through the piston  4   a  so that the release bearing  2  is pushed leftward to disengage the friction clutch  1 . In the process for disengaging the clutch  1  from its engaged state, the oil in the intermediate chamber  8   c  of the intermediate cylinder  8  is returned to the oil tank  21  from the pipe  14  through the solenoid valves  19  and  19 ′ and through the pipe  20 . 
     If the clutch pedal  5  is returned, the piston  7   a  in the master cylinder  7  is returned rightward as viewed in FIG. 3 by a spring in the master cylinder  7 , and at the same time, the oil in the slave cylinder  4  is returned to the left chamber  8   b  of the intermediate cylinder  8  through the pipe  9  by the returning movement of the piston  4   a  by a spring in the friction clutch  1  through the release bearing  2  and the clutch release fork  3 . The second piston  12  moves, together with the spring force, the first piston  11  rightward as viewed in FIG. 3, so that the friction clutch  1  is engaged. 
     The present invention will be described in detail based on an example shown in FIG. 1, together with FIGS. 2 and 3. The starting apparatus for the vehicle having the a electronic control clutch of the present invention, which engages and disengages the clutch  1  by the clutch hydraulic actuator  23 , electronically controlled in accordance with output signal from the above-described various detecting means which detect the driving state, includes a coil  41   a  of a starter cut relay  41  having normally-closed contacts. The relay is connected to an output terminal  24   a  of the electronic control unit  24 , with one of the contacts  41   b  of the relay  41  being connected to one end of a relay coil  43   a  of a starter relay  43  relay  43  is connected at the other end of the relay coil  43   a  to a power source V through a key switch  42 . The other contact  41   c  of the cut relay  41  is connected to a non-grounded side contact  44   a  of a neutral relay  44 . Relay  44  is connected between a neutral switch  29 ′ connected to the power source and an input terminal  24   b  of the electronic control unit  24 . A gear stroke sensor  45 , capable of detecting the neutral of the shift operation of the transmission, is connected to input terminals  24   c,    24   d  and  24   e  of the electronic control unit  24 . In FIG. 1, the reference symbols  43   b  and  43   c  represent contacts of the starter relay  43 , and the reference symbol  44   b  representing the grounded-side contact of the neutral relay  44 . 
     In the case of the present invention, incorporated in the electronic control unit  24  is logic which does not allow the electric current flow to the coil  41   a  of the starter cut relay  41  when the neutral switch  29 ′ and the gear stroke sensor  45  are normal that is when the neutral switch  29 ′ is ON and the gear stroke sensor  45  indicates that the shift position of the transmission is in the neutral. However, the control unit  24  allows the electric current to flow to the coil  41   a  of the starter cut relay  41  from the output terminal  24   a  of the electronic control unit  24 , thereby opening the circuit between the contacts  41   b  and  41   c  so that the starter relay  43  is not operated when any of the neutral switch  29 ′ or the gear stroke sensor  45  is abnormal, the neutral switch  29 ′ is OFF or the shift position of the transmission is in other than the neutral. 
     As described above, both the neutral switch  29 ′ and the gear stroke sensor  45  are connected to the input terminal  24   b,    24   c  and  24   d  of the electronic control unit  24 . With this arrangement, in the electronic control unit  24 , there is also incorporated logic for judging that the shift position is surely in neutral if both the neutral switch  29 ′ and the gear stroke sensor  45  outputs signals indicating that input from the shift position is neutral, and for judging that either one of the neutral switch  29 ′ and the gear stroke sensor  45  is abnormal if signals output from the neutral switch  29 ′ and the gear stroke sensor  45  are different. Therefore, it is possible to judge that either one of the neutral switch  29 ′ and the gear stroke sensor  45  is abnormal. 
     In the starter apparatus of the present invention having the above-described structure, when the neutral switch  29 ′ and the gear stroke sensor  45  are normal, the neutral switch  29 ′ is ON and the gear stroke sensor  45  indicates that the shift position of the transmission is in the neutral, the neutral relay  44  closes from the dotted line to the solid line, and since no electric current flows to the coil  41   a  of the starter cut relay  41 , its contact is kept in its normally-closed state. Therefore, if the key switch  42  is turned ON, the electric current of the power source flows through the key switch  42 , the coil  43   a  of the starter relay  43 , and flows between the normally-closed contacts  41   b  and  41   c  of the starter cut relay, and between the contacts  44   a  and  44   b  of the neutral relay  44 , and is grounded. Therefore, the starter relay  43  closes the circuit between the contacts  44   b  and  44   c  to start the starter motor  46 . 
     Further, when either one of the neutral switch  29 ′ and the gear stroke sensor  45  is abnormal, or when the neutral switch  29 ′ is OFF or the shift position of the transmission is in other than the neutral, the electric current is flowed from the output terminal  24   a  of the electronic control unit  24  to the coil  41   a  of the starter cut relay  41 , thereby opening the circuit between the contacts  41   b  and  41   c.  Therefore, even if the key switch  42  is turned ON, since the circuit between the normally-closed contacts  41   b  and  41   c  of the starter cut relay or the circuit between the contacts  44   a  and  44   b  of the neutral relay  44  is opened, the electric current of the power source does not flow, and the starter motor  46  can not be started. 
     If the electronic control unit  24  should be out of order, and even if the portion within the dotted line is removed for exchanging the electronic control unit  24 , according to the starting apparatus of the present invention, as long as the neutral switch  29 ′ is normal, since the switch  29 ′ is ON, the neutral relay  44  is closed from the dotted line to the solid line, and the starter cut relay  41  is kept in its normally-closed state. Therefore, by turning the key switch  42  ON, the electric current of the power source flows through the key switch  42 , the coil  43   a  of the starter relay  43 , and flows between the normally-closed contacts  41   b  and  41   c  of the starter cut relay, and between the contacts  44   a  and  44   b  of the neutral relay  44 , and is grounded in the same manner as that described above. Therefore, the starter relay  43  closes the circuit between the contacts  44   b  and  44   c  so that the starter motor  46  can be started. In this case, it is necessary to operate the clutch  1  manually. 
     Therefore, in the starting apparatus for a vehicle having the electronic control clutch of the present invention, even if the electronic control unit  24  should be out of order and removed, as long as the neutral switch  29 ′ is normal, since the switch  29 ′ is ON, the neutral relay  44  is closed, and the starter cut relay  41  is kept in its normally-closed state. Therefore, by turning the key switch  42  ON, it is possible to start the starter motor  46  through the starter relay  43 , and by manually operating the clutch  1 , the vehicle can be used as usual. 
     In the starting apparatus, if signals from the neutral switch  29 ′ and the gear stroke sensor  45  are included in the output signals of the above-described various detecting means, and if the starting apparatus is designed such that when the electronic control unit  24  judges that the output signals from the neutral switch  29 ′ and the gear stroke sensor  45  are different, the signal is output so as to operate the starter cut relay  41 , it is possible to sense the abnormality of the neutral switch  29 ′ and the gear stroke sensor  45 . 
     REFERENCE 
       1  friction clutch 
       2  release bearing 
       3  clutch release fork 
       4  slave cylinder 
       5  clutch pedal 
       6 ,  21  oil tank 
       7  master cylinder 
       8  intermediate cylinder 
       9 ,  10 ,  13 ,  14 ,  20  pipe 
       11  first piston 
       12  second piston 
       15  check valve 
       16  motor 
       17  hydraulic pump 
       18  relief valve 
       19 ,  19 ′ solenoid valves 
       22  clutch stroke detecting means 
       23  clutch hydraulic actuator 
       24  electronic control unit 
       25  transmission revolution sensor 
       26  vehicle speed sensor 
       27  vehicle speed detecting means 
       28  vehicle speed detecting means 
       29  gearshift position detecting means 
       29 ′ neutral switch 
       30  shift knob 
       31  shift knob grasp detecting means 
       32  clutch automating switch 
       33  clutch pedal switch 
       34  brake pedal 
       35  brake detecting means 
       36  accelerator switch 
       36 ′ accelerator opening degree detecting means 
       37  parking brake detecting means 
       38  detecting means for the opening of a door 
       39  indicator lamp 
       40  warning mechanism 
       41  starter out relay 
       42  key switch 
       43  starter relay 
       44  neutral relay 
       45  gear stroke sensor 
       46  starter motor