Electronic control apparatus for vehicle and diagnosing method thereof

• US 20070192001A1
• Filed: 01/19/2007
• Published: 08/16/2007
• Est. Priority Date: 01/20/2006
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Abe, Kazuhiko, Kubota, Mitsuhiko, Tatsumi, Motoki
• Granted Patent: US 7,765,041 B2
• Time in Patent Office: Days
• US Class Current: 701/29
• CPC Class Codes: B60W 50/04 Monitoring the functioning of the control system
• CPC Class Codes: F01L 1/34 characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
• CPC Class Codes: F01L 13/0026 by means of an eccentric
• CPC Class Codes: F01L 2001/0537 Double overhead camshafts [DOHC]
• CPC Class Codes: F01L 2013/0073 with an oscillating cam acting on the valve of the "Delphi" type
• CPC Class Codes: F01L 2800/00 Methods of operation using a variable valve timing mechanism
• CPC Class Codes: F01L 2800/12 Fail safe operation
• CPC Class Codes: F01L 2820/032 Electric motors
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/26 using computer, e.g. microprocessor

Abstract

An electronic control apparatus for a vehicle having an engine control unit 114 controlling an electronically-controlled throttle of an engine and a valve control unit 141 controlling a variable lift mechanism 112 that varies a lift amount of an intake valve are provided. Information of a target lift amount and an actual lift amount is transmitted/received between these control units. Each of the control units diagnoses a state of data transmission from the other control unit, transmits the diagnosis result to the other control unit and, when the diagnosis result of itself and/or the diagnosis result of the other control unit shows an abnormal state, moves to the mode of a fail-safe operation.

Claims

1. An electronic control apparatus for a vehicle, comprising:

a plurality of control units associable in communication with one another; and

a communication circuit that provides a connection for the communication among the plurality of control units,

wherein each of the plurality of control units diagnoses a data reception abnormality, transmits a diagnosis result, and diagnoses an abnormality in the communication circuit on the basis of the diagnosis result of itself and a diagnosis result of a control unit as an associated side in the communication.

2. The electronic control apparatus for a vehicle according to claim 1, wherein each of the plurality of control units determines an abnormality in the communication circuit when a reception abnormality is determined as at least one of the diagnosis result of the control unit itself and the diagnosis result of the control unit as the associated side in the communication.

3. The electronic control apparatus for a vehicle according to claim 1, wherein when a data reception abnormality is determined, each of the plurality of control units moves to a fail-safe mode, and

at least one of the plurality of control units switches its control in accordance with degree of the abnormality in the communication circuit in the fail-safe mode.

4. The electronic control apparatus for a vehicle according to claim 3, wherein at least one of the plurality of control units determines the degree of the abnormality in the communication circuit on the basis of time in which an abnormal state of the communication circuit continues.

5. The electronic control apparatus for a vehicle according to claim 3, wherein at least one of the plurality of control units determines the degree of the abnormality in the communication circuit on the basis of the number of times that successive determinations of an abnormal state in the communication circuit is performed.

6. The electronic control apparatus for a vehicle according to claim 3, wherein at least one of the plurality of control units distinctively determines the degree of an abnormality in the communication circuit as a minor abnormality or a serious abnormality, and wherein said at lease one control unit controls a controlled object on the basis of a target value for the fail-safe mode when a minor abnormality is determined, and controls the controlled object to an off state when a serious abnormality is determined.

7. The electronic control apparatus for a vehicle according to claim 1, wherein the plurality of control units include a first control unit for controlling an electronically-controlled throttle of an engine mounted on a car and a second control unit for controlling a variable valve mechanism that makes an open characteristic of an intake valve of the engine variable, and wherein

the first control unit transmits a target value of the open characteristic of the intake valve to the second control unit, and

the second control unit transmits a detection value of the open characteristic of the intake valve to the first control unit.

8. The electronic control apparatus for a vehicle according to claim 7, wherein when an abnormality in the communication circuit is determined, the second control unit controls the variable valve mechanism to thereby bring the open characteristic of the intake valve into a predetermined open characteristic, and while

when the first control unit determines an occurrence of an abnormality in the communication circuit, said first control unit estimates that the open characteristic of the intake valve has become the predetermined open characteristic, to control the electronically-controlled throttle thereby obtaining a target intake air amount in the predetermined open characteristic.

9. The electronic control apparatus for a vehicle according to claim 7, wherein each of the first and second control units distinctively determines degree of an abnormality in the communication circuit as a minor abnormality or a serious abnormality, and wherein

when a minor abnormality is determined, the second control unit controls the variable valve mechanism to bring the open characteristic of the intake valve into a predetermined open characteristic,

when a minor abnormality is determined, the first control unit estimates that the open characteristic of the intake valve has become the predetermined open characteristic to control the electronically-controlled throttle such that a target intake air amount in the predetermined open characteristic is obtained,

when a serious abnormality is determined, the second control unit controls the variable valve mechanism to an off state, and

when a serious abnormality is determined, the first control unit controls the variable valve mechanism to an off state, to thereby control the electronically-controlled throttle such that a target air-fuel ratio in the off state of the variable valve mechanism is obtained.

10. The electronic control apparatus for a vehicle according to claim 7, wherein the variable valve mechanism comprises a mechanism for continuously varying a lift amount and an operation angle of the intake valve.

11. An electronic control apparatus for a vehicle, comprising:

a plurality of control means associable in communication with one another; and

communication means for providing a connection for communication among the plurality of control means,

wherein each of the plurality of control means diagnoses a data reception abnormality, transmits the diagnosis result, and diagnoses an abnormality in the communication means on the basis of the diagnosis result of itself and a diagnosis result of an associated control means that is associated in the communication with each other.

12. A diagnosing method of an electronic control apparatus for a vehicle, having a plurality of control units associable in communication with one another and a communication circuit that provides a connection for communication among the plurality of control units, the method comprising the steps of:

diagnosing a data reception abnormality by each of the plurality of control units;

transmitting the diagnosis result from each of the plurality of control units; and

diagnosing an abnormality in the communication circuit by each of the plurality of control units on the basis of the diagnosis result of the control unit itself and a diagnosis result of an associated control unit that is associated in the communication.

13. The diagnosing method of an electronic control apparatus for a vehicle according to claim 12, wherein in the step of diagnosing an abnormality in the communication circuit,

an abnormality in the communication circuit is determined when a reception abnormality is determined as at least one of the diagnosis result of the control unit itself and the diagnosis result of the associated control unit in the communication.

14. The diagnosing method of an electronic control apparatus for a vehicle according to claim 12, further comprising the steps of:

allowing each of the plurality of control units to move to a fail-safe mode in the case where an abnormality in the communication circuit is determined; and

switching controlling by at least one of the plurality of control units in the fail-safe mode in accordance with degree of the abnormality in the communication circuit.

15. The diagnosing method of an electronic control apparatus for a vehicle according to claim 14, wherein the step of switching the controlling in accordance with the degree of the abnormality in the communication circuit includes the steps of:

measuring time in which the abnormal state of the communication circuit continues; and

determining the degree of the abnormality in the communication circuit on the basis of the measured time.

16. The diagnosing method of an electronic control apparatus for a vehicle according to claim 14, wherein the step of switching the controlling in accordance with the degree of the abnormality in the communication circuit includes the steps of:

counting the number of times that the abnormal state of the communication circuit is successively determined; and

determining the degree of the abnormality in the communication circuit on the basis of the number of times.

17. The diagnosing method of an electronic control apparatus for a vehicle according to claim 14, wherein the step of switching the controlling in accordance with the degree of the abnormality in the communication circuit includes the steps of:

distinctively determining the degree of an abnormality in the communication circuit as a minor abnormality or a serious abnormality;

when a minor abnormality is determined, controlling a controlled object on the basis of a target value for the fail-safe mode; and

when a serious abnormality is determined, controlling the controlled object to an off state.

18. The diagnosing method of an electronic control apparatus for a vehicle according to claim 12, wherein the plurality of control units includes a first control unit for controlling an electronically-controlled throttle of an engine mounted on a car and a second control unit for controlling a variable valve mechanism that makes an open characteristic of an intake valve of the engine variable, and the method further includes the steps of:

transmitting a target value of the open characteristic of the intake valve from the first control unit to the second control unit, and

transmitting a detection value of the open characteristic of the intake valve from the second control unit to the first control unit.

19. The diagnosing method of the electronic control apparatus for a vehicle according to claim 18, further comprising the steps of:

when an abnormality in the communication circuit is determined, controlling the variable valve mechanism to bring the open characteristic of the intake valve into a predetermined open characteristic by the second control unit; and

when an abnormality in the communication circuit is determined, estimating that the open characteristic of the intake valve has become the predetermined open characteristic by the first control unit, and controlling the electronically-controlled throttle so as to obtain a target intake air amount in the predetermined open characteristic.

20. The diagnosing method of an electronic control apparatus for a vehicle according to claim 18, further comprising the steps of:

distinctively determining the degree of an abnormality in the communication circuit as a minor abnormality or a serious abnormality by the first and second control units;

when a minor abnormality in the communication circuit is determined, controlling the variable valve mechanism by the second control unit so that the open characteristic of the intake valve becomes a predetermined open characteristic;

when a minor abnormality in the communication circuit is determined, estimating that the open characteristic of the intake valve has become the predetermined open characteristic and controlling the electronically-controlled throttle so as to obtain a target intake air amount in the predetermined open characteristic by the first control unit;

when a serious abnormality in the communication circuit is determined, controlling the variable valve mechanism to an off state by the second control unit; and

when a serious abnormality in the communication circuit is determined, controlling the variable valve mechanism to an off state and controlling the electronically-controlled throttle so as to obtain a target air-fuel ratio in the off state of the variable valve mechanism by the first control unit.