Control apparatus with fail-safe faculty

• US 5,216,938 A
• Filed: 03/28/1991
• Issued: 06/08/1993
• Est. Priority Date: 03/28/1990
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Corporation
• Inventors: Yamaguchi, Hiroshi
• Primary Examiner(s): Herrmann, Allan D.
• Assistant Examiner(s): TROUSDELL, WILLIAM
• Application Number:
  US07/676,406
• Time in Patent Office: 803 Days
• Field of Search: 74/866, 74/867, 364/424.1, 364/426.01, 364/426.02, 364/426.03, 364/426.04, 364/431.01, 364/431.03, 364/431.04, 364/431.11, 364/131, 364/133, 371/68.1, 371/68.3
• US Class Current: 477/107
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 30/18027 Drive off, accelerating from standstill
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: B60W 50/038 Limiting the input power, torque or speed
• CPC Class Codes: F16H 2061/1208 with diagnostic check cycles; Monitoring of failures
• CPC Class Codes: F16H 2061/122 Avoiding failures by using redundant parts
• CPC Class Codes: F16H 2061/1224 Adapting to failures or work around with other constraints, e.g. circumvention by avoiding use of failed parts
• CPC Class Codes: F16H 2061/1268 Electric parts of the controller, e.g. a defect solenoid, wiring or microprocessor
• CPC Class Codes: F16H 2061/1284 the failing part is a sensor
• CPC Class Codes: F16H 2312/02 Driving off
• CPC Class Codes: F16H 2342/044 Torque transmitting capability
• CPC Class Codes: F16H 61/0437 by using electrical signals F16H61/0403 and F16H61/061 take precedence
• CPC Class Codes: F16H 61/12 Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures
• CPC Class Codes: F16H 63/502 for smoothing gear shifts
• CPC Class Codes: G05B 9/02 electric
• CPC Class Codes: Y10S 477/906 Means detecting or ameliorating the effects of malfunction or potential malfunction

Abstract

In a control apparatus with fail-safe faculty for controlling an output torque of a vehicle including an electronically controlled fuel-injection type engine and an automatic transmission having a torque converter and a speed change gear mechanism, in which when an abnormal start operation causing a racing select shock is detected, an output torque of the engine is reduced by stopping a supply of a fuel to all or half cylinders of the engine in dependent upon the engine running speed, a clutch transfer torque capacity is reduced by reducing a line pressure of the speed change gear mechanism, and a gear position of the speed change gear mechanism is shifted into a second gear position, the improvements being characterized in that when a system failure in which one of sensors and actuators becomes out of order or a communication line between an engine control computer and a transmission control computer becomes out of order occurs, the reduction of the engine output torque is performed upon the abnormal start operation without fail. Further, one of the reduction of the clutch transfer torque capacity and the shift of the gear position into the second gear position, which may be conducted without being affected by the system failure is performed. In a preferable embodiment, upon the system failure, the fuel supply to a larger number of cylinders is stopped, the clutch transfer torque capacity is reduced to a larger extent and the gear position is shifted into a third gear position in response to the abnormal start operation.

Claims

1. A control apparatus with fail-safe faculty for controlling a driving power of an automotive vehicle including an electronically controlled engine and an automatic transmission having a torque converter, an automatic speed change gear mechanism, and a manual gear select control and a controllable variable torque transfer capacity clutch, comprising:

sensing means including a plurality of sensors for detecting operational conditions of the vehicle and generating a corresponding plurality of detection signals;

judging means for processing said detection signals and generating an abnormal start signal when said detection signals have a predetermined state, said predetermined state indicating that an abnormal mechanical shock condition would occur when a driver effects a change of the manual gear select control of said speed change gear mechanism;

first controlling means for reducing an output power of the engine in response to said abnormal start signal;

p1 second controlling means for reducing a transfer torque capacity of the variable torque transfer capacity clutch of said speed change gear mechanism of the automatic transmission in response to said abnormal start signal; and

third controlling means for controlling said speed change gear mechanism of the automatic transmission in response to said abnormal signal such that a gear position is shifted into a predetermined gear position at which an output torque of the automatic transmission is lower than a value which is produced under a normal start operation;

a means for detecting a failure in one of said plurality of sensors of the sensing means; and

means for controlling a predetermined one of said first, second and third controlling means in response to said detected failure to perform a predetermined control of one of an ouptut power of the engine, a transfer torque capacity of the variable torque transfer capacity clutch and a gear position of said speed change gear mechanism.

2. A control apparatus according to claim 1, wherein said first, second and third controlling means are constructed such that when said system failure occurs, at least one controlling means which may work correctly without being affected by said system failure is operated in addition to said predetermined controlling means.

3. A control apparatus according to claim 1, wherein said predetermined controlling means is the first controlling means for reducing the output power of the engine in response to the abnormal start signal.

4. A control apparatus according to claim 3, wherein said first controlling means is constructed such that in response to said abnormal start signal, the number of cylinders of the engine to which a fuel is supplied is reduced.

5. A control apparatus according to claim 4, wherein said first controlling means is constructed such that when the engine running speed is higher than a first value, the fuel supply to all the cylinders of the engine is stopped in response to said abnormal start signal, and when the engine running speed is not higher than said first value, but is higher than a second value, the fuel supply to half the cylinders is stopped in response to said abnormal start signal.

6. A control apparatus according to claim 5, wherein said first value is set to 2500 RPM and said second value is set to 2200 RPM.

7. A control apparatus with fail-safe faculty for controlling a driving power of an automotive vehicle including an electronically controlled fuel-injection type engine and an automatic transmission having a torque converter, an automatic speed change gear mechanism, and a manual gear select control, comprising:

sensing means including a plurality of sensors for detecting operational conditions of the automotive vehicle to generate detection signals;

judging means for processing said detection signals and generating an abnormal start signal when said detection signals have a predetermined state, said predetermined state indicating a predetermined abnormal mechanical shock condition would occur when a driver effects a change of a manual control of said speed change gear mechanism;

first controlling means for performing a first control in which an output power of the engine is reduced in response to said abnormal start signal;

second controlling means for performing a second control in which a clutch transfer torque capacity of said speed change gear mechanism of the automatic transmission is reduced in response to said abnormal start signal; and

third controlling means for performing a third control in which said speed change gear mechanism of the automatic transmission is controlled such that a gear position is shifted in response to said abnormal start signal into a predetermined gear position at which an output torque of the automatic transmission becomes lower than a value which is produced under a normal start operation;

means for detecting a failure of one of said first, second and third controlling means and for generating a corresponding failure signal,

wherein said first, second and third controlling means have a means for determining, in response to said failure signal, that one of said first, second and third controls can not be performed due to a system failure, and a means for performing the remaining two controls by a predetermined changing of operational characteristics of these two controls in response to said determining.

8. A control apparatus according to claim 7, wherein said first controlling means is constructed such that under no system failure, the fuel supply to all cylinders of the engine is stopped in response to said abnormal start signal when the engine running speed is higher than a first value, and the fuel supply to half the cylinders is stopped when the engine running speed is not higher than the first value, but is higher than a second value;

and under the system failure, the fuel supply to all the cylinders of the engine is stopped in response to said abnormal start signal when the engine running speed is higher than the first value, and the fuel supply to two thirds the cylinders is stopped when the engine running speed is not higher than the first value, but is higher than the second value.

9. A control apparatus according to claim 8, wherein said first value is set to 2500 RPM and said second value is set to 2200 RPM.

10. A control apparatus according to claim 7, wherein said second controlling means is constructed such that said clutch transfer torque capacity is reduced in response to said abnormal start signal by reducing a line pressure of the speed change gear mechanism.

11. A control apparatus according to claim 10, wherein said line pressure is reduced to a first value when said abnormal start signal is generated under no system failure, and said line pressure is reduced to a second value which is lower than said first value when said abnormal start signal is produced under the system failure.

12. A control apparatus according to claim 11, wherein said line pressure is reduced by decreasing a duty cycle of a driving signal for a duty solenoid.

13. A control apparatus according to claim 7, wherein said third controlling means is constructed such that under no system failure, the gear position of the speed change gear mechanism of the automatic transmission is shifted into a second gear position in response to said abnormal start signal, and under the system failure, the gear position is shifted into a third gear position in response to the abnormal start signal.

14. A control apparatus with fail-safe faculty for controlling a driving power of an automotive vehicle including an electronically controlled fuel-injection type engine and an automatic transmission having a torque converter, an automatic speed change gear mechanism controlled by a manual select lever and a controllable variable torque transfer capacity clutch, comprising:

an engine control computer for performing a first control in which an output torque of the engine is reduced in response to an abnormal start operation signal;

a transmission control computer for performing a second control in which an output torque of the automatic transmission is reduced in response to the abnormal start operation signal;

a communication line connected between the engine control computer and the transmission control computer;

first and second engine running sensors for detecting the engine running speed (N_E) and connected to said engine control computer and transmission control computer, respectively;

first and second vehicle running speed sensors for detecting the vehicle running speed (V) and connected to said engine control computer and transmission control computer, respectively;

first and second inhibitor switches for detecting a range position (S) selected by said manual select lever and connected to said engine control computer and transmission control computer, respectively;

a throttle sensor for detecting a throttle opening (T_H) and connected parallely to said engine control computer and transmission control computer;

an intake air sensor for detecting an intake air quantity (Q) and connected to said engine control computer; and

input and ouptut rotation speed sensors for detecting rotation speeds of input and output shafts, respectively, of the speed change gear mechanism and outputting an input and output rotation speed signal, respectively, to said transmission control computer;

means for detecting a failure of said second engine running speed sensor and generating a second engine running speed sensor failure signal in response thereto;

means for detecting a failure of said second inhibitor switch and generating a second inhibitor switch failure signal in response thereto;

wherein transmission control computer has means, in response to the concurrent absence of said second engine running speed sensor failure signal and said second inhibitor switch failure signal, for generating the abnormal start signal representing the abnormal start operation by processing the engine running speed (N_E) detected by said second engine running speed sensor and the range position (S) detected by said second inhibitor switch and for supplying said abnormal start signal to the engine control computer via said communication line to perform said first control, and wherein said transmission control computer has means for generating a system failure signal in response to one of said second engine running speed sensor failure signal and second inhibitor switch failure signal, and means for supplying said system failure signal to said engine control computer, and wherein

said engine control computer has means for generating, in response to said system failure signal, the abnormal start signal by processing the engine running speed (N_E) detected by said first engine running speed sensor and the range position (S) detected by said first inhibitor switch to perform the first control.

15. A control apparatus according to claim 14, wherein said engine control computer and transmission control computer have a means for detecting a failure of said communication line and, said engine control computer has means for performing, in response to said detected failure, said first control in response to the abnormal start signal generated by the engine control computer, and said transmission control computer has a means for performing, in response to the detected failure of said communication line, said second control in response to the abnormal start signal generated by the transmission control computer.

16. A control apparatus according to claim 15, wherein said engine control computer has a means for performing said first control by reducing the number of cylinders of the engine to which a fuel is supplied.

17. A control apparatus according to claim 16, wherein said engine control computer has a means for responding to the abnormal start signal in the absence of the system failure signal by stopping the fuel supply to all of the cylinders of the engine in response to said abnormal start signal when the engine running speed (N_E) is higher than a first value, and by stopping the fuel supply to half of the cylinders when the engine running speed N_E is not higher than the first value but is higher than a second value.

18. A control apparatus according to claim 17, wherein said first value is set to 2500 RPM and said second value is set to 2200 RPM.

19. A control apparatus according to claim 15, wherein said transmission control computer has a means for performing said second control by decreasing the clutch transfer torque capacity of the speed change gear mechanism in response to said abnormal start signal and by shifting the gear position of the speed change gear mechanism in response to said abnormal start signal into a predetermined gear position, said predetermined gear position being such that a starting operation output torque of the automatic transmission is lower at said predetermined gear position than a value which is produced under a start operation in the absence of the abnormal start signal.

20. A control apparatus according to claim 19, wherein said transmission control computer is constructed such that said gear position is shifted into a second gear position in response to the abnormal start signal.

21. A control apparatus according to claim 19, wherein said transmission control computer is constructed such that the clutch transfer torque capacity is reduced in response to said abnormal start signal by reducing a line pressure of the speed change gear mechanism.

22. A control apparatus according to claim 21, wherein said line pressure is reduced by decreasing a duty cycle of a driving signal for a duty solenoid.

23. A control apparatus with fail-safe faculty for performing a plurality of controls upon a subject, comprising:

sensing means including at least a first sensor for detecting an operational condition of the subject and generating a corresponding first detection signal, and a second sensor for detecting the same operational condition as detected by said first sensor and generating a corresponding second detection signal;

controlling means having a first control circuit connected to said first sensor for receiving said first detection signal therefrom and for producing a first control signal in response thereto, and a second control circuit for receiving said second detection signal therefrom and for producing a second control signal in response thereto;

actuating means having a first actuator for performing a first control for said subject in response to said first control signal, and a second actuator for performing a second control for said subject in response to said second control signal, said second control being different from said first control;

means for detecting a failure of said first sensor and for detecting a failure of said second sensor, and for outputting a sensor failure signal in accordance with a corresponding detected sensor failure; and

signal communicating means for transmitting said first and second detection signals between the first and second control circuits, said signal communicating means having a means responsive to said sensor failure signal for transmitting, to the one of the first and second control circuits connected to the one of the first and second sensors indicated by said failure signal to have a detected failure, the other of said first and second sensor detection signals, wherein

said first and second control circuits have a means for controlling said first and second actuators, respectively, in a first predetermined failure control in response to said failure signal, and a means for controlling at least one of said first and second actuators to perform at least one of said first and second controls when controlling said first and second actuators in said first predetermined failure control, and

said first and second circuits have a means for detecting a failure of said signal communication means and, in response to said detected failure, for controlling at least one of said first and second actuators to perform a second predetermined failure control.