Electronic control system for internal combustion engine with stall preventive feature and method for performing stall preventive engine control

• US 4,721,083 A
• Filed: 10/31/1984
• Issued: 01/26/1988
• Est. Priority Date: 11/04/1983
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Hosaka, Akio
• Primary Examiner(s): Wolfe, Jr., Willis R.
• Application Number:
  US06/666,360
• Time in Patent Office: 1,182 Days
• Field of Search: 123/325, 123/326, 123/339, 123/493, 180/165, 180/69.3
• US Class Current: 477/111
• CPC Class Codes: F02D 41/083 taking into account engine load variation, e.g. air-conditionning
• CPC Class Codes: F02D 41/2406 using essentially read only memories
• CPC Class Codes: F02D 41/2496 the memory being part of a closed loop

Abstract

An engine control system includes a stall-preventive feature in which prevailing engine conditions are checked against patterns known to lead to engine stall. A number of crucial engine parameters and continuously monitored, as are one or a number of subsidiary conditions, such as air conditioner operation and transmission position, which may significantly increase the probability of engine stall under certain, known conditions. When these known conditions are detected, engine parameters are sampled at regular intervals for a predetermined period of time to derive a number of parameter variation curves or patterns which can then be compared to similarly-derived empirical patterns which are known to lead directly to engine stall. When the current and predetermined patterns match or closely correlate, the engine control system is signalled to perform a stall-preventive operation. The stall-preventive operation consists of steps serving to increase engine output torque, decrease the load on the engine or both. For example, the fuel supply may be adjusted in accordance with the predetermined variation patterns. Alternatively, if the air conditioner is running, it may be turned off temporarily until the danger of stalling has passed. In addition, auxiliary devices capable of generating torque independently of the engine may be used briefly to supplement the engine output.

Claims

1. A stall preventive control system for an internal combustion engine comprising:

first sensors, each of which monitors a preselected engine operation parameter and produces a first sensor signal indicative thereof;

second detector for detecting the operating state of a preselected engine operation-influencing vehicle component and producing a second detector signal indicative thereof;

third means, associated with said first sensors, for detecting engine operating conditions on the basis of said first sensor signals and producing an engine stall-indicative third signal when engine conditions known to lead to stalling are detected;

fourth means, responsive to said third signal, for recording the values of said first sensor signals and said second detector signal as an engine stall condition representative data set, said fourth means recording a engine stall condition representative data set upon every occurence of said third signal;

fifth means, responsive to said first sensor signals, for deriving engine operating condition data and comparing said derived engine operating condition data with said engine stall condition representative data and producing a fourth signal when said engine operating condition data satisfies a predetermined relationship with one set of the engine stall condition representing data; and

fifth means, responsive to said sixth signal, for performing a predetermined engine stall preventive operation which increases the engine output torque factor relative to the load on the engine.

2. A stall preventive control system for an internal combustion engine comprising:

a first sensor for producing an engine speed indicative first sensor signal;

a reference signal generator for producing a second signal representative of an engine speed low enough to lead to engine stalling;

second means for comparing a value of said first sensor signal with said second signal and producing an engine stall indicative signal if said first sensor signal value is less than said second signal;

an auxiliary drive unit responsive to said engine stall indicative signal for transmitting torque to the engine while the engine is operating under its own power in order to increase the engine output torque relative to the load on the engine, said auxiliary drive unit comprising a starter motor which is independent of another starter motor used for engine cranking and which is responsive to said engine stall indicative signal to temporarily apply additional torque to an engine output shaft.

3. A stall preventive control system for an internal combustion engine comprising:

a first sensor for producing an engine speed indicative first sensor signal;

a reference signal generator for producing a second signal representative of an engine speed low enough to lead to engine stalling;

second means for comparing said first sensor signal value with said second signal and producing an engine stall indicative signal if said first sensor signal value is less than said second signal value;

an auxiliary drive unit responsive to said engine stall indicative signal for transmitting torque to the engine while the engine is operating under its own power in order to increase the engine output torque relative to the load on the engine, comprising an alternator for generating electric power, also operative as an electrically driven motor, and responsive to said stall indicative signal to operate as an electrically driven motor to apply torque to the engine.

4. A method for controlling an internal combustion engine comprising the steps of:

monitoring a preselected engine operation parameter;

detecting engine operating conditions on the basis of the monitored engine operation parameter;

detecting engine conditions known to lead to stalling on the basis of the detected operating condition;

recording said engine operation parameter at a moment said engine stall condition is detected as engine stall condition representative data, and accumulating another set of engine stall condition representative data each time the engine stall condition is detected; and

comparing detected engine operating conditions with said engine stall condition representative data and performing a prdetermined engine stall-preventive operation, in which the engine output torque is increased relative to the load on the engine, when the detected engine operating condition satisfies a specific relationship with at least one set of said engine stall condition representative data.

5. A method for performing stall preventive control for an internal combustion engine, comprising the steps of:

monitoring an engine operating parameter;

detecting engine operating conditions on the basis of the detected engine operating parameter and determining a pattern of variations in said detected operating conditions over time;

detecting an engine condition known to lead to engine stalling on the basis of detected engine operating conditions by comparing said pattern of variations in said detected operating conditions over time with a known pattern of operating conditions over time which have a high probability of leading to engine stall; and

driving an auxiliary drive unit associated with said engine while the engine is running under its own power so as to apply additional torque to the engine when said engine stalling condition is detected.

6. A method for projecting a possible occurrence of engine stall during engine operation, comprising the steps of:

monitoring variations in engine operation parameters;

detecting engine operating conditions on the basis of engine operating parameters;

detecting engine conditions known to lead to engine stalling on the basis of detected engine operating conditions;

recording a pattern of variation of said engine operation parameters each time the engine stalling condition is detected; and

comparing the monitored variations of said engine operating parameters with said set engine operation parameter variation patterns to detect engine conditions which may lead to engine stall.

7. A stall preventive control system for an internal combustion engine comprising:

sensor means for monitoring a preselected engine operation parameter and producing a first sensor signal indicative thereof;

means, responsive to said first signal for monitoring variations of said first sensor signal value over a given period of time for establishing an engine driving condition variation pattern and producing a second signal indicative thereof;

means, responsive to said second signal and including means for storing a preset engine operating condition variation pattern over time, which preset pattern is representative of engine operating having a high probability to cause stall, for comparing said variation pattern as indicated by said second signal and said preset pattern for detecting incipient engine stall based on said second signal and producing a third signal when incipient engine stall is detected; and

fourth means, associated with said third means and responsive to said third signal, for performing an engine stall preventive operation in which the magnitude of engine output torque relative to the load on the engine is increased.

8. A stall preventive control system for an internal combustion engine comprising:

a first sensor for monitoring a preselected engine operation parameter and producing a first sensor signal indicative thereof;

a second detector for detecting a preselected engine operating condition on the basis of a pattern of variations over time in said first sensor signal and producing a second detector signal indicative thereof;

third means, responsive to said second detector signal, for detecting incipient engine stall based on said second detector signal and producing a third signal when incipient engine stall is detected; and

fourth means, associated with said third means and responsive to said third signal, for performing an engine stall preventive operation in which the magnitude of engine output torque relative to the load on the engine is increased, said fourth means comprising a starter motor engageable with the engine and driven by an electrical power source to apply additional torque to the engine in response to said third signal, wherein said starter motor performing said engine stall preventive operation is installed as an auxiliary unit independent of another starter motor used to crank the engine.

9. The engine control system as set forth in claim 8, which further comprises an alternator for generating electric power, said alternator being associated with said fourth means, which in response to said third signal controls the operation mode of said alternator to act as an electric motor driven by a battery power to transmit additional torque to the engine.

10. A stall preventive control system for an internal combustion engine comprising:

a first sensor for monitoring a preselected engine operation parameter and producing a first sensor signal indicative thereof;

a second detector for detecting a preselected engine operating condition of the basis of a pattern of variations over time in said first sensor signal and producing a second detector signal indicative thereof;

third means, responsive to said second detector signal and including means for storing a preset engine operating condition variation pattern over time, which preset pattern is representative of engine operation having a high possibility of resulting in engine stall, for comparing said variation pattern as indicated by said second detector signal and said preset pattern for detecting incipient engine stall based on said second detector signal and producing a third signal when incipient engine stall is detected; and

fourth means, associated with said third means and responsive to said third signal, for performing an engine stall preventive operation in which the magnitude of engine output torque relative to the load on the engine is increased.

11. The engine control system as set forth in claim 10, which further comprises a starter motor engageable with the engine, said starter motor being associated with said fourth means to be engaged to the engine and driven by an electrical power source to apply additional torque to the engine in response to said third signal.

12. The engine control system as set forth in claim 10, which further comprises a flywheel engageable with said engine and normally driven by the engine for accumulating engine output in the form of angular momentum, said flywheel supplying additional torque to the engine in response to said third signal.

13. A stall preventive control system for an internal combustion engine comprising:

a first sensor for producing an engine speed indicative first sensor signal indicative of a pattern of engine speed variations over time;

a reference signal generator for producing a second signal representative of an engine speed variation pattern over time which is indicative of a high probability of resulting in engine stalling;

second means for comparing said first sensor signal with said second signal and producing an engine stall indicative signal if said first sensor signal is less than said second signal and remains less than said second sensor signal for a predetermined length of time;

an auxiliary drive unit responsive to said engine stall indicative signal for transmitting torque to the engine while the engine is operating under its own power in order to increase the engine output torque relative to the load on the engine.

14. The engine control system as set forth in claim 13, wherein said auxiliary device is a starter motor which is responsive to said engine stall indicative signal to temporarily apply additional torque to an engine output shaft.

15. The engine control system as set forth in claim 13, wherein said auxiliary device comprises a flywheel driven by engine to accumulate engine power in the form of angular momentum, and responsive to said engine stall indicative signal to return accumulated power to said engine.

16. A stall preventive control system for an internal combustion engine comprising:

a first sensor for producing an engine speed indicative first sensor signal;

a reference signal generator for producing a second signal representative of an engine speed low enough to lead to engine stalling;

second means for comparing said first sensor signal value with said second signal and producing an engine stall indicative signal if said first sensor signal value is less than said second signal value;

an auxiliary drive unit responsive to said engine stall indicative signal for transmitting torque to the engine while the engine is operating under its own power in order to increase the engine output torque relative to the load on the engine, comprising a flywheel driven by the engine to accumulate engine power in the form of angular momentum, and responsive to said engine stall indicative signal to return accumulated power to said engine, wherein said flywheel is connected to an engine output shaft through an electromagnetically operable clutch engaged in response to said engine stall indicative signal.

17. The engine control system as set forth in claim 16, wherein said clutch is engaged when the engine speed is higher than a predetermined speed which is sufficiently high to drive said flywheel without adversely influencing engine performance as well as in response to said engine stall indicative signal.

18. The engine control system as set forth in claim 17, wherein said clutch is engaged to connect said flywheel to said engine output shaft only when engine speed is sufficiently high and the engine is decelerating.

19. A stall preventive control system for an internal combustion engine comprising:

a first sensor for monitoring a preselected engine operation parameter and producing a first sensor signal indicative thereof;

a second detector for detecting a preselected engine operating condition on the basis of variations in said first sensor signal and producing a second detector signal indicative thereof;

third means, responsive to said second detector signal, for detecting incipient engine stall and producing a third signal when incipient engine stall is detected; and

fourth means, associated with said third means and responsive to said third signal, for performing an engine stall preventive operation in which the magnitude of engine output torque relative to the load on the engine is increased,

wherein said fourth means records said first sensor signal as engine stall condition-indicative data in response to detection of incipient engine stall, compares said engine stall condition-indicative data with said second detector signal and outputs said third signal whenever said second detector signal satisfies a predetermined specific relationship with one of the recorded engine stall condition-indicative data.

20. The engine control system as set forth in claim 19, wherein said engine includes an air induction system including an auxiliary air induction system bypassing a throttle valve, a fuel injection system for injecting fuel into the stream of intake air entering the engine, an ignition system for performing spark ignition in engine cylinders, an exhaust gas recirculation system for recirculating a fraction of the exhaust gas exitting the engine into the intake air stream, and a sixth means controlling the auxiliary air flow rate, the fuel injection amount and timing, the ignition timing and the exhaust gas recirculation rate.

21. The engine control system as set forth in claim 19, which further comprises a fifth detector for detecting the operating state of a vehicle component, affecting engine operation, and said engine stall preventive operation consists of controlling the operating state of said vehicle component.

22. The engine control system as set forth in claim 21, wherein said vehicle component is a transmission gear position.

23. The engine control system as set forth in claim 21, wherein said first sensor monitors engine speed.

24. The engine control system as set forth in claim 21, wherein said first sensor monitors intake air flow rate.

25. The engine control system as set forth in claim 21, wherein said first sensor monitors the pressure of engine lubrication oil.

26. The engine control system as set forth in claim 21, wherein said vehicle component is an air conditioner driven by the engine.

27. The engine control system as set forth in claim 26, wherein said fourth means disables said air conditioner in order to decrease the load on the engine and so increase the relative magnitude of the engine output torque.

28. A stall preventive control system for an internal combustion engine comprising:

a first sensor for monitoring a preselected engine operation parameter and producing a first sensor signal indicative thereof;

a second detector associated with said first sensor for detecting instantaneous engine operating conditions and producing a second detector signal indicative of the engine operating conditions;

a third means, for recording said first sensor signal value as engine stall condition-indicative data in response to the second detector signal indicative of engine conditions known to lead to stalling;

fourth means, responsive to said second detector signal, for deriving engine operating condition data and comparing the derived engine operating condition data with said engine stall condition-indicative data to output a third signal indicative of engine conditions known to lead to stalling with a high probability when said engine operating condition satisfies a predetermined relationship with said engine stall condition-indicative data; and

fifth means, associated with an accessory device of an engine, for operating said accessory device in response to said third signal so as to increase the magnitude of the engine output torque relative to the load on the engine.

29. The engine control system as set forth in claim 28, wherein said accessory device comprises an alternator for generating electric power and operative as an electrically driven motor, and said fifth means responds to said third signal by operating said alternator as an electrically driven motor to apply torque to the engine to increase the total engine output torque.

30. The engine control system as set forth in claim 29, wherein said first sensor monitors engine speed and produces an engine speed-indicative first sensor signal, said third means produces a reference signal indicative of an engine speed low enough to lead to stalling, and said fourth means compares said engine speed-indicative first sensor signal value with said reference signal value and produces said third signal if said first sensor signal value is less than said reference value.

31. The engine control system as set forth in claim 28, which further comprises a sixth detector for detecting the operating state of said accessory device, the operation of which influences engine operation, and said fourth means selects which of a plurality said engine stall condition-indicative data is to be compared with said engine operating condition data depending upon the operating state of said accessory device.

32. The engine control system as set forth in claim 31, wherein said accessory device is an air conditioner including a compressor driven by the engine.

33. The engine control system as set forth in claim 32, wherein said fifth means temporarily disables said air conditioner in response to said third signal.

34. The engine control system as set forth in claim 28, wherein said accessory device is a starter motor, and said fifth means is responsive to said third signal to temporarily operate said starter motor to transmit additional torque from said starter motor to an engine output shaft.

35. The engine control system as set forth in claim 34, wherein said starter motor is independent of another starter motor used for engine cranking.

36. The engine control system as set forth in claim 35, wherein said first sensor monitors engine speed and produces an engine speed-indicative first sensor signal, said third means produces a reference signal indicative of an engine speed low enough to lead to stalling, and said fourth means compares said engine speed-indicative first sensor signal value with said reference signal value and produces said third signal if said first sensor signal value is less than said reference value.

37. The engine control system as set forth in claim 28, wherein said accessory device comprises a flywheel driven by the engine to accumulate engine power in the form of angular momentum, and said fifth means is responsive to said third signal to operate said flywheel to return accumulated power to said engine.

38. The engine control system as set forth in claim 37, wherein said flywheel is connected to an engine output shaft through an electromagnetically operable clutch, and said fifth means controls the engagement and disengagement of said clutch.

39. The engine control system as set forth in claim 38, wherein said clutch is engaged when the engine speed is higher than a predetermined speed which is sufficiently high to drive said flywheel without adversely influencing engine performance, and said fifth means engages said clutch in response to said third signal.

40. The engine control system as set forth in claim 39, wherein said clutch is engaged to connect said flywheel to said engine output shaft only when engine speed is sufficiently high and the engine is decelerating.

41. The engine control system as set forth in claim 40, wherein said first sensor monitors engine speed and produces an engine speed-indicative first sensor signal, said third means produces a reference signal indicative of an engine speed low enough to lead to stalling, and said fourth means compares said engine speed-indicative first sensor signal value with said reference signal value and produces said third signal if said first sensor signal value is less than said reference value.

42. The engine control system as set forth in claim 28, wherein each of engine stall condition-indicative data consists of a plurality of first sensor signal values sampled at regular intervals for a predetermined period of time after each second detector signal.

43. The engine control system as set forth in claim 42, wherein said fourth means derives said engine operating condition data in the same manner as said engine stall condition-indicative data, and said fourth means calculates the integral of the absolute difference between corresponding values of said engine stall-indicative data and said engine operating condition data and produces said third signal when said integral value is smaller than a given value.

44. The engine control system as set forth in claim 43, wherein said first sensor monitors engine revolution speed.

45. The engine control system as set forth in claim 44, wherein said third means includes a memory storing variation patterns of engine speed leading to engine stalling as said engine stall condition-indicative data.

46. The engine control system as set forth in claim 45, wherein said fourth means compares said engine operating condition data with each variation pattern of said engine stall condition-indicative data and produces said third signal if the integral of the absolute difference between corresponding values of said engine operating condition data and any of said engine stall condition-indicative data variation patterns is equal to or smaller than said given value.

47. The engine control system as set forth in claim 46, wherein said accessory device comprises an automotive air conditioner including a compressor driven by the engine, and said fifth means temporarily disables said air conditioner in response to said third signal.

48. The engine control system as set forth in claim 46, wherein said accessory device comprises an alternator for recharging a vehicle battery, and said fifth means reduces the load on said alternator in response to said third signal.