Speed limiter

• US 20020152987A1
• Filed: 04/23/2002
• Published: 10/24/2002
• Est. Priority Date: 12/24/1999
• Status: Active Grant

• Current Assignee: Orbital Engine Company Pty Limited (Orbital Corporation Limited)
• Original Assignee: Orbital Engine Company Pty Limited (Orbital Corporation Limited)
• Inventors: Worth, David Richard, Woolford, Richard Albert, Taylor, Mark John
• Granted Patent: US 6,755,177 B2
• Time in Patent Office: Days
• US Class Current: 123/333
• CPC Class Codes: F02D 2041/227 Limping Home, i.e. taking specific engine control measures at abnormal conditions
• CPC Class Codes: F02D 31/009 for maximum speed control

Abstract

A method of controlling the engine speed of an internal combustion engine, the method including the steps of determining the engine speed demanded by an operator of the engine and comparing this demanded engine speed with a predetermined engine speed limit, wherein if the demanded engine speed exceeds the predetermined engine speed limit, the fuelling rate demanded of the operator is only reduced in order to control the engine speed to the predetermined engine speed limit.

Claims

1. A method of controlling the engine speed of an internal combustion engine, the method including the steps of determining the engine speed demanded by an operator of the engine and comparing this demanded engine speed with a predetermined engine speed limit, wherein if the demanded engine speed exceeds the predetermined engine speed limit, the fuelling rate demanded by the operator is only reduced in order to control the engine speed to the predetermined engine speed limit.

2. A method according to claim 1, wherein if the demanded engine speed is less than the predetermined engine speed limit, then no change is made to the normal operation of the engine.

3. A method according to claim 1 or 2, wherein when the demanded engine speed exceeds the predetermined engine speed limit, the actual fuelling rate to the engine never exceeds that corresponding to the predetermined engine speed limit.

4. A method according to any one of the preceding claims, wherein a controller implemented to govern the engine fuelling rate to control the engine speed to the predetermined engine speed limit operates exclusively in a uni-directional manner to only ever reduce the demanded fuelling rate.

5. A method according to any one of the preceding claims, wherein the level of reduction of the demanded engine fuelling rate is a function of the demanded engine speed.

6. A method according to claim 5, wherein the actual amount of fuel to be delivered to the engine is determined by considering the difference between the demanded engine speed and the engine speed limit and reducing the demanded fuelling level accordingly.

7. A method according to any one of the preceding claims, wherein the amount of reduction to the demanded fuelling rate is directly controlled by the operator, the actuation of a throttle means by the operator serving as an input which assists determination of the reduction to the demanded fuelling rate when the demanded engine speed is above the predetermined engine speed limit.

8. A method according to claim 7, wherein, once the predetermined engine speed limit has been exceeded, the amount of reduction required to the demanded fuelling rate increases as the degree of opening of the throttle means increases.

9. A method according to claim 1, 2 or 3 wherein a maximum or set amount of fuel is delivered once the predetermined engine speed limit has been reached, the fuelling rate returning to normal levels when the demanded engine speed subsequently falls below the predetermined engine speed limit.

10. A method according to any one of the preceding claims, wherein control over the engine speed is effected by a fuel-led control system.

11. A method according to any one of the preceding claims, wherein the engine speed is controlled to the predetermined engine speed limit in order to provide a limp-home mode of engine operation.

12. A method according to any one of the preceding claims, wherein speed entry ramps are implemented to facilitate a smooth transition to the predetermined engine speed, the entry ramps being determined as a function of the rate of change of the engine speed prior to attainment of the predetermined engine speed limit.

13. A method according to any one of claims 7 to 12, wherein a certain level of dampening is applied to the change in position of the throttle means effected by the operator.

14. A method according to any one of the preceding claims, wherein the ability for the engine to be controlled to the predetermined engine speed limit is enabled by the use of programmable key or card.

17. A method according to claim 16, including maintaining the actual engine fuelling rate at a level that is necessary to achieve the predetermined engine speed when operating in said speed limited mode.

18. A method according to claim 16 or 17, including using said modified event timings when the air-fuel ratio to the engine varies from the typical air-fuel ratio at the predetermined engine speed.

31. An ECU according to any one of the preceding claims, wherein control over the engine speed is effected by a fuel-led control system.

15. A method of controlling the speed of a vehicle, the method including the steps of determining the vehicle speed demanded by an operator of the vehicle and comparing this demanded vehicle speed with a predetermined vehicle speed limit, wherein if the demanded vehicle speed exceeds the predetermined vehicle speed limit, the fuelling rate demanded by the operator is only reduced in order to control the vehicle speed to the predetermined vehicle speed limit.

16. A method of controlling the engine speed of an internal combustion engine including operating the engine in a speed limited mode in response to a demanded engine speed exceeding a predetermined engine speed limit, wherein modified event timings are used during said speed limited mode, said modified event timings varying from the normal event timings which would otherwise be used at the predetermined engine speed.

19. A method according to any one of claims 16, 17, or 18, wherein the engine includes a dual-fluid fuel injection system, and modified event timings are used for at least one of start of fuel metering (SOF), end of fuel metering (EOF), start of air injection (SOA), end of air injection (EOA) or ignition (IGN) when the engine is operating in said speed limited mode.

20. A method according to any one of claims 16 to 18, wherein when the engine is operating outside of the speed limited mode, the normal event timings are selected as a function of total fuel per cycle and engine speed.

21. A method according to any one of claims 16 to 20, wherein when the engine is operating in said speed limited mode, the modified event timings are determined as a function of total fuel per cycle and throttle position.

22. A method according to any one of claims 16 to 20, wherein when the engine is operating in said speed limited mode, the modified event timings are determined as a function of total fuel per cycle and air flow.

23. A method according to claim 22, wherein total fuel per cycle, engine speed, throttle position and air flow are ordinates for respective electronic look-up maps which are stored in an electronic unit which manages the operation of the engine.

24. A method according to any one of claims 16 to 23, wherein so as to avoid an undesirable transition from the normal event timings to the modified event timings, the modified event timings are consulted just prior to attainment of the predetermined engine speed limit.

25. A method according to any one of claims 16 to 24, wherein control over the engine speed is effected by a fuel-led control system.

27. An ECU according to claim 26, wherein when the demanded engine speed exceeds the predetermined engine speed limit, the actual fuelling rate to the engine never exceeds that corresponding to the predetermined engine speed limit.

28. An ECU according to claim 26 or 27, wherein a controller implemented to govern the engine fuelling rate to control the engine speed to the predetermined engine speed limit operates exclusively in a uni-directional manner to only ever reduce the demanded fuelling rate.

30. An ECU according to claim 29, wherein the actual amount of fuel to be delivered to the engine is determined by considering the difference between the demanded engine speed and the engine speed limit and reducing he demanded fuelling level accordingly.

26. An ECU adapted to control the engine speed of an inherent combustion engine, including the steps of determining the engine speed demanded by an operator of the engine and comparing this demanded engine speed with a predetermined engine speed limit, wherein if the demanded engine speed exceeds the predetermined engine speed limit, the fuelling rate demanded by the operator is only reduced in order to control the engine speed to the predetermined engine speed limit.

29. An ECU according to any one of claims 26 to 28, wherein the level of reduction of the demanded engine fuelling rate is a function of the demanded engine speed.

32. An ECU adapted to control the engine speed of an internal combustion engine including operating the engine in a speed limited mode in response to a demanded engine speed exceeding a predetermined engine speed limit, wherein modified event timings are used during said speed limited mode, said modified event timings varying from the normal event timings which would otherwise be used at the predetermined engine speed.

33. An ECU according to claim 32, including maintaining the actual engine fuelling rate at a level that is necessary to achieve the predetermined engine speed when operating in said speed limited mode.

34. An ECU according to claim 32 or 33, including using said modified event timings when the air-fuel ratio to the engine varies from the typical air-fuel ratio at the predetermined engine speed.

35. An ECU according to any one of claims 32, 33 or 34, wherein the engine includes a dual-fluid fuel injection system, and modified event timings are used for at least one of start of fuel metering (SOF), end of fuel metering (EOF), start of air injection (SOA), end of air injection (EOA) or ignition (IGN) when the engine is operating in said speed limited mode.

36. An ECU according to any one of claims 33 to 35, wherein when the engine is operating in said speed limited mode, the modified event timings are determined as a function of total fuel per cycle and throttle position.

37. An ECU according to any one of claims 32 to 36, wherein when the engine is operating in said speed limited mode, the modified event timings are determined as a function of total fuel per cycle and air flow.

38. An ECU according to claim 37, wherein total fuel per cycle, engine speed, throttle position and air flow are ordinates for respective electronic look-up maps which are stored in an electronic unit which manages the operation of the engine.

39. An ECU according to any one of claims 32 to 38, wherein control over the engine speed is effected by a fuel-led control system.