Method and system for engine control

• US 5,477,827 A
• Filed: 05/16/1994
• Issued: 12/26/1995
• Est. Priority Date: 05/16/1994
• Status: Expired due to Term

• Current Assignee: Detroit Diesel Corporation (Daimler Truck Holding AG)
• Original Assignee: Detroit Diesel Corporation (Daimler Truck Holding AG)
• Inventors: Thomas, Eric D., Weisman, S. Miller II, VanderBok, Arnold J.
• Primary Examiner(s): Nelli, Raymond A.
• Application Number:
  US08/243,103
• Time in Patent Office: 589 Days
• Field of Search: 123/436, 123/419, 364/424.01, 364/432.08, 364/431.03, 364/431.05
• 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 31/047 the memory being digital
• 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 2555/20 Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 30/146 Speed limiting
• 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 2031/00 Fail safe
• CPC Class Codes: F01P 2060/06 Retarder
• CPC Class Codes: F01P 7/08 by cutting in or out of pumps
• CPC Class Codes: F02D 11/105 characterised by the function converting demand to actuation, e.g. a map indicating relations between an accelerator pedal position and throttle valve opening or target engine torque
• CPC Class Codes: F02D 11/106 Detection of demand or actuation
• 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 2200/0625 Fuel consumption, e.g. measured in fuel liters per 100 kms or miles per gallon
• CPC Class Codes: F02D 2200/1002 : Output torque
• CPC Class Codes: F02D 2200/703 : Atmospheric pressure
• 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 37/00 : Non-electrical conjoint control of two or more functions of engines, not otherwise provided for
• CPC Class Codes: F02D 41/0007 : for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/0085 : Balancing of cylinder outputs, e.g. speed, torque or air-fuel ratio
• CPC Class Codes: F02D 41/0087 : Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• 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 41/1497 : With detection of the mechanical response of the engine
• 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
• CPC Class Codes: F02D 41/38 : of the high pressure type
• CPC Class Codes: F02D 43/00 : Conjoint electrical control of two or more functions, e.g. ignition, fuel-air mixture, recirculation, supercharging or exhaust-gas treatment
• CPC Class Codes: F16H 63/40 : comprising signals other than signals for actuating the final output mechanisms
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/84 : Data processing systems or methods, management, administration

Abstract

A method for comprehensive integrated control of an internal combustion engine, such as a compression-ignition engine, utilizing an electronic control module is disclosed. The control strategy integrates various functions of engine control including an acceleration balance test for the engine cylinders, a fuel economy vehicle speed limit adder, a fueling limit for high altitude vehicle operation, throttle logic, a data-hub for operation trending and vehicle component lifing analyses, a gear ratio torque limit, an air temperature based torque limit, enhanced fan control, and an idle shutdown strategy based on ambient temperature.

Claims

1. A method for balancing power output in a vehicle including an internal combustion engine controlled by an electronic control module, the engine having a plurality of cylinders, each cylinder having an associated fuel injector for dispensing fuel to the cylinder, said method implemented by the electronic control module comprising:

operating the engine at a predetermined idle speed and permitting the engine to stabilize;

cutting off fuel dispensed by the fuel injectors to at least one of the cylinders so as to define at least one cut off cylinder;

measuring acceleration RPM of the engine; and

modifying the fuel dispensed to the fuel injectors based on the measured acceleration RPM so as to balance power output of each cylinder.

2. The method of claim 1 wherein the step of measuring acceleration RPM of the engine comprises operating the engine for a predetermined number of engine revolutions while dispensing fuel to those fuel injectors not included in the at least one cut off cylinder according to a fueling scheme which ensures occurrence of a predetermined number of cylinder firings.

3. The method of claim 1 wherein the step of modifying includes determining a temporary fuel injector pulsewidth adjustment factor for each of the at least one cut off cylinder, based on the measured acceleration RPM.

4. The method of claim 3 further comprising determining a normalizing factor for each of the at least one cut off cylinder based on the temporary fuel injector pulsewidth adjustment factors.

5. The method of claim 4 wherein modifying the fuel dispensed includes modifying fuel injector pulsewidth based on the normalizing factor.

6. A method for improving fuel economy in a vehicle including an internal combustion engine in communication with an electronic control module having a vehicle speed parameter for storing a value representing a permissible vehicle speed, said method implemented by the electronic control module comprising the steps of:

determining a filtered fuel economy;

determining a vehicle speed adder based on the determined filtered fuel economy; and

modifying the value of the vehicle speed parameter utilizing the speed adder; and

controlling the engine based on the modified value of the vehicle speed parameter.

7. The method of claim 6 wherein the step of determining a filtered fuel economy comprises utilizing a first order lag calculation limited between predetermined limits.

8. The method of claim 6 wherein the step of determining a filtered fuel economy comprises evaluating:

space="preserve" listing-type="equation">FIL.sub.MPG =min(MPG.sub.-- LIM+THRESH.sub.MPG, max(THRE(FIL.sub.MPG.sbsb.t-1 +MPG.sub.-- FILT.sub.CON *(INST.sub.MPG -,

wherein MPG_-- LIM represents the maximum permissible deviation from a fleet fuel economy goal, THRESH_MPG represents a threshold fuel economy, MPG_-- FILT_CON is a fuel economy filter constant, INST_MPG represents an instantaneous fuel economy, and FIL_MPGt-1 represents a previously determined filtered fuel economy.

9. The method of claim 6 wherein the step of determining a vehicle speed adder comprises evaluating:

space="preserve" listing-type="equation">MPGMPH=min(MAX.sub.-- MPH.sub.MPG, MPH.sub.-- MPG.sub.GN *max

wherein MAX_-- MPH_MPG represents a maximum amount by which the value of the vehicle speed parameter may be increased, and MPH_-- MPG_GN is a fuel economy gain.

10. The method of claim 6 wherein the value of the vehicle speed parameter may be increased only after a threshold fuel economy has been attained.

11. A method for preventing damage to a turbocharger of a vehicle including an electronic control module for controlling an internal combustion engine equipped with said turbocharger, said method implemented by the electronic control module comprising the steps of:

determining a torque modifier based on a value indicative of current barometric pressure;

determining a limit torque based on the torque modifier; and

limiting fuel delivery to the engine based on the limit torque so as to limit turbocharger speed to prevent damage to the turbocharger.

12. The method of claim 11 wherein the step of determining a torque modifier comprises determining a torque modifier according to:

##EQU7## wherein RPM_MX represents engine speed for maximum barometric pressure compensation, TRQ_MN represents minimum torque after compensation, RPM_MN represents minimum RPM for compensation, PR_TQ represents pressure gain for compensation, and PR_MN represents minimum pressure for compensation.

13. The method of claim 12 wherein the step of determining a limit torque comprises determining a limit torque according to:

space="preserve" listing-type="equation">HATQ=min(1, TRQ.sub.MN +max(0, TMP)).

14. A system for sampling vehicular operating conditions of a vehicle equipped with an internal combustion engine and an electronic control module for controlling the engine, the system comprising:

a plurality of sensors for providing signals indicative of vehicular operating information wherein at least one of the plurality of sensors is in communication with the electronic control module;

a memory in communication with the electronic control module for maintaining sampled information from the electronic control module in a plurality of pages; and

a microprocessor in communication with the memory and with the electronic control module, the microprocessor for cooperating with the electronic control module to maintain a plurality of trends pages in the memory, each trends page including a predetermined number of samples, the trends pages providing an indication of at least one of a plurality of vehicle operating conditions or driver performance.

15. The system of claim 14 wherein the microprocessor maintains the plurality of trends pages for at least one of the group consisting of oil pressure, turbocharger boost pressure, battery voltage, fuel economy, oil temperature, coolant temperature, engine speed, vehicle speed, and minimum throttle position sensor voltage.

16. The system of claim 14 wherein the microprocessor performs vehicle service interval analyses for predetermined vehicle components based upon at least one of the group consisting of vehicle distance traveled, engine hours used, calendar time, total engine revolutions, total fuel combusted, and engine idle time.

17. A method for throttle logic in a vehicle including an internal combustion engine controlled by an electronic control module and a vehicle operator-controlled throttle for controlling the amount of fuel delivered to the engine, said method implemented by the electronic control module comprising the steps of:

obtaining an impulse filtered throttle position offset by filtering the raw value of a throttle position sensor output;

determining a smoothed throttle position offset based on the impulse filtered throttle position offset and a variable filter constant;

determining a computed throttle position offset based on a throttle position hysteresis and the smoothed offset; and

controlling the engine based on the computed throttle position offset.

18. The method of claim 17 wherein the step of determining a smoothed throttle position offset comprises determining a smoothed throttle position offset utilizing a filter constant having a value which varies based on relative values of the impulse filtered throttle position offset and a previously determined smoothed throttle position offset.

19. The method of claim 18 wherein the step of determining a smoothed throttle position offset comprises determining the smoothed throttle position offset according to

20. The method of claim 18 wherein the step of determining a smoothed throttle position offset comprises determining the smoothed offset according to

21. A method for preventing engine damage in a vehicle including an electronic control module for controlling an internal combustion engine having a plurality of cylinders and a corresponding plurality of pistons reciprocating in the plurality of cylinders, said method implemented by the electronic control module for preventing damage to any of the plurality of cylinders and pistons during vehicle operation, said method comprising:

determining temperature of air inlet to the engine during a combustion cycle;

measuring operating speed of the engine;

determining an engine torque limit based on the determined temperature and the measured operating speed of the engine; and

controlling the engine based on the determined engine torque limit so as to prevent damage to any of the plurality of cylinders and pistons.

22. The method of claim 21 wherein the step of determining an engine torque limit comprises determining the engine torque limit according to:

##EQU8## wherein AIT represents the temperature of air inlet, ATNRPM represents engine speed at or below which ATTQ is 100% for any air inlet temperature, ATQMAX represents maximum engine torque limit, ATQMIN represents minimum absolute torque limit, ATTQ represents an absolute torque limit and is a factor in determining rampdown torque, ATXRPM represents engine speed at or above which maximum torque reduction is permitted for current engine speed, and ENGRPM represents normal engine RPM averaged over degrees of rotation based on the plurality of engine cylinders.

23. A method for preventing transmission damage in a vehicle having a drivetrain including an electronic control module for controlling an internal combustion engine, the vehicle also including a transmission coupled to the engine, said method implemented by the electronic control module for controlling engine torque to prevent damage to the transmission, the method comprising:

determining a virtual gear ratio based on engine speed and vehicle speed; and

limiting torque produced by the engine based on the value of the virtual gear ratio so as to prevent damage to the transmission.

24. The method of claim 23 wherein the step of determining a virtual gear ratio (VGR) comprises determining the virtual gear ratio according to:

space="preserve" listing-type="equation">VGR=ES/VS

wherein ES represents the engine speed and VS represents the vehicle speed.

25. The method of claim 23 further comprising comparing the virtual gear ratio to at least one torque limit threshold, wherein the step of limiting torque produced by the engine includes limiting the torque to a particular torque if the virtual gear ratio exceeds the at least one torque limit threshold.