System and method for selectively limiting engine output

• US 6,220,223 B1
• Filed: 10/19/1999
• Issued: 04/24/2001
• Est. Priority Date: 08/27/1993
• Status: Expired due to Fees

• Current Assignee: Detroit Diesel Corporation (Daimler Truck Holding AG)
• Original Assignee: Detroit Diesel Corporation (Daimler Truck Holding AG)
• Inventors: LeTang, Dennis M., Weisman, S. Miller II
• Primary Examiner(s): Yuen, Henry C.
• Assistant Examiner(s): Vo, Hieu T.
• Application Number:
  US09/420,496
• Time in Patent Office: 553 Days
• Field of Search: 123/436, 123/350, 123/352, 123/480, 180/197, 180/248, 180/249
• US Class Current: 123/436
• CPC Class Codes: B60K 31/04 and means for comparing one electrical quantity, e.g. voltage, pulse, waveform, flux, or the like, with another quantity of a like kind, which comparison means is involved in the development of an electrical signal which is fed into the controlling means
• CPC Class Codes: B60K 31/045 in a memory, e.g. a capacitor
• CPC Class Codes: B60K 31/047 the memory being digital
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 2050/0022 Gains, weighting coefficients or weighting functions
• CPC Class Codes: B60W 2050/0042 Transfer function lag; delays
• CPC Class Codes: B60W 2050/0052 Filtering, filters
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/0676 Engine temperature
• CPC Class Codes: B60W 2555/20 Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 2710/0616 Position of fuel or air injector
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 30/146 Speed limiting
• CPC Class Codes: B60W 30/18054 at stand still, e.g. engine in idling state hill holding B60W30/18118
• CPC Class Codes: B60W 30/192 Mitigating problems related to power-up or power-down of the driveline, e.g. start-up of a cold engine
• CPC Class Codes: F01P 2023/00 Signal processing; Details thereof
• CPC Class Codes: F01P 2023/08 Microprocessor; Microcomputer
• CPC Class Codes: F01P 2025/08 Temperature
• CPC Class Codes: F01P 2025/13 Ambient temperature
• CPC Class Codes: F01P 2025/40 : Oil temperature
• CPC Class Codes: F01P 2025/46 : Engine parts temperature
• CPC Class Codes: F01P 2031/00 : Fail safe
• CPC Class Codes: F01P 2060/06 : Retarder
• CPC Class Codes: F01P 7/04 : by varying pump speed, e.g. by changing pump-drive gear ratio
• CPC Class Codes: F01P 7/048 : using electrical drives
• CPC Class Codes: F01P 7/08 : by cutting in or out of pumps
• CPC Class Codes: F02B 3/06 : with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02D 17/04 : rendering engines inoperative or idling, e.g. caused by abnormal conditions dependent on lubricating conditions F01M1/22; dependent on cooling F01P5/14
• CPC Class Codes: F02D 2041/1432 : the system including a filter, e.g. a low pass or high pass filter
• CPC Class Codes: F02D 2200/0414 : Air temperature
• CPC Class Codes: F02D 2200/1002 : Output torque
• CPC Class Codes: F02D 2200/501 : Vehicle speed
• CPC Class Codes: F02D 2250/16 : End position calibration, i.e. calculation or measurement of actuator end positions, e.g. for throttle or its driving actuator
• CPC Class Codes: F02D 2250/18 : Control of the engine output torque
• CPC Class Codes: F02D 2250/26 : by applying a torque limit
• CPC Class Codes: F02D 41/0225 : in relation with the gear ratio or shift lever position
• CPC Class Codes: F02D 41/042 : for stopping the engine
• CPC Class Codes: F02D 41/086 : taking into account the temperature of the engine
• CPC Class Codes: F02D 41/222 : relating to the failure of sensors or parameter detection devices
• CPC Class Codes: F16H 63/40 : comprising signals other than signals for actuating the final output mechanisms
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/84 : Data processing systems or methods, management, administration

Abstract

A system and method for controlling an engine to limit engine output include determining engine speed, determining vehicle speed, determining a ratio based on the engine speed and the vehicle speed, comparing the ratio to a threshold, and controlling the engine to limit engine output based on the comparison. The ratio used for comparison may be selected from a plurality of ratios based on a current gear ratio which may be an actual or virtual (computed) gear ratio. The threshold may represent a low gear torque limit threshold in one embodiment. A vehicle speed sensor fault may also be considered to determine whether to limit the engine output. In one embodiment, engine output is limited by limiting engine torque.

Claims

1. A system for controlling an internal combustion engine to selectively limit engine torque, the system comprising:

means for determining a gear ratio;

means for comparing the determined gear ratio to a threshold value corresponding to a predetermined actual gear ratio and limiting engine torque when the determined gear ratio exceeds the threshold value.

2. The system of claim 1 wherein the means for determining a virtual gear ratio.

3. The system of claim 1 wherein the means for determining a gear ratio comprises:

means for determining an engine speed; and

means for determining a vehicle speed.

4. The system of claim 3 further comprising:

means for detecting a vehicle speed sensor fault; and

means for limiting engine torque when a vehicle speed sensor fault is detected.

5. A computer readable storage medium having stored data representing instructions executable by a microprocessor to control a diesel engine to selectively limit engine output, the storage medium comprising data representing:

instructions for calculating a gear ratio;

instructions for comparing the calculated gear ratio to a threshold value representing a predetermined actual gear ratio;

instructions for controlling the diesel engine to limit engine output when the calculated gear ratio exceeds the threshold.

6. The computer readable storage medium of claim 5 further comprising data representing:

instructions for detecting a vehicle speed sensor fault; and

instructions for reducing available engine torque when a vehicle speed sensor fault is detected.

7. The computer readable storage medium of claim 5 wherein the instructions for calculating a gear ratio comprise:

instructions for determining an engine speed; and

instructions for determining a vehicle speed.

8. A system for controlling an engine to limit engine output under certain conditions, the system comprising:

an engine speed sensor for providing an engine speed signal indicative of engine rotational speed;

a vehicle speed sensor for providing a vehicle speed signal indicative of vehicle speed;

a controller in communication with the engine speed sensor and the vehicle speed sensor, the controller including a microprocessor in communication with a memory having instructions executable by the microprocessor for determining engine speed based on the engine speed signal, instructions for determining vehicle speed based on the vehicle speed signal, instructions for determining a ratio based on the engine speed and the vehicle speed, instructions for comparing the ratio to a threshold value, and instructions for controlling the engine to limit engine output based on the comparison.

9. The system of claim 8 wherein the controller includes instructions for detecting a vehicle speed sensor fault and instructions for controlling the engine to limit engine output when a vehicle speed sensor fault is detected.

10. The system of claim 8 wherein the instructions for controlling the engine include instructions for reducing available engine torque when the ratio exceeds the threshold value.

11. The system of claim 8 wherein the threshold value corresponds to a predetermined actual gear ratio.

12. The system of claim 8 wherein the instructions for controlling the engine include instructions for reducing available engine torque when the ratio exceeds the threshold value by a predetermined amount.

13. A method for controlling a diesel engine having an engine speed sensor for providing a signal indicative of engine rotational speed, the engine mounted in a vehicle having a vehicle speed sensor for providing a signal indicative of vehicle speed, the method comprising:

processing the signal indicative of engine rotational speed to determine an engine speed;

processing the signal indicative of vehicle speed to detect a vehicle speed sensor fault; and

reducing available engine torque when the vehicle speed sensor fault is detected.

14. The method of claim 13 wherein the step of reducing available engine torque comprises selecting the lower of a low gear limit torque, a smoke control torque, and a rampdown torque.

15. A method for controlling an engine, the method comprising:

determining a vehicle speed;

determining an engine speed;

computing a gear ratio based at least in part on the determined engine speed and vehicle speed;

comparing the gear ratio to a threshold value; and

limiting engine output when the gear ratio differs from the threshold value by a predetermined amount.

16. The method of claim 15 wherein the step of limiting engine output comprises reducing available engine torque.

17. The method of claim 15 wherein the step of limiting engine output comprises limiting engine output when the gear ratio exceeds the threshold by a predetermined amount.

18. The method of claim 15 wherein the gear ratio is a virtual gear ratio corresponding to the determined engine speed divided by the vehicle speed.

19. The method of claim 15 further comprising:

monitoring the vehicle speed to detect a vehicle speed sensor fault; and

limiting engine output when a vehicle speed sensor fault is detected.

20. A method for controlling an engine, the method comprising:

determining engine speed;

determining vehicle speed;

determining a ratio based on the engine speed and the vehicle speed;

comparing the ratio to a threshold value; and

controlling the engine to limit engine output based on the step of comparing.

21. The method of claim 20 wherein the step of controlling comprises controlling the engine to limit engine output torque.

22. The method of claim 20 wherein the step of controlling comprises controlling the engine to limit engine output based on the ratio exceeding the threshold.

23. The method of claim 20 wherein the step of controlling comprises controlling the engine to limit engine output based on the ratio being less than or equal to the threshold.

24. The method of claim 20 wherein the step of determining a ratio comprises determining a virtual gear ratio.

25. The method of claim 24 wherein the step of determining a virtual gear ratio comprises determining a ratio of engine speed divided by vehicle speed.

26. The method of claim 20 further comprising selecting one of a plurality of threshold values based on a corresponding plurality of actual gear ratios, wherein the step of comparing comprises comparing the selected threshold value to the determined ratio.

27. The method of claim 20 wherein the threshold is a low gear torque limit threshold.

28. The method of claim 20 further comprising detecting a vehicle speed sensor fault, wherein the step of controlling the engine includes controlling the engine to limit engine output when a vehicle speed sensor fault is detected.

29. The method of claim 20 wherein the threshold value corresponds to a predetermined actual gear ratio.