Control system for regulating output torque of an internal combustion engine

Abstract

An engine control system is operable to provide an engine fueling rate equal to the larger of a first engine fueling rate at which the resulting engine torque is limited by a maximum input torque capacity of a presently engaged gear ratio of the transmission and a second engine fueling rate at which the resulting engine torque is limited by a nominal input torque capacity of the transmission. The foregoing technique can be enabled at all times, or alternatively only after determination that the vehicle is experiencing deceleration under heavy engine load conditions. The engine control system may be further operable to determine a third engine fueling rate at which the resulting engine output torque is limited by a maximum operating torque capacity of the transmission propeller shaft, as well as a fourth engine fueling rate at which the resulting engine output torque is limited by a maximum operating torque capacity of the drive axle connected thereto. The actual engine fueling rate is then chosen to be the minimum of the larger of the first and second engine fueling rates, the third engine fueling rate, and the fourth engine fueling rate. This technique can be enabled either at all times, or alternatively only when the presently engaged gear ratio is corresponds to one of a set of lower gear ratios gears of the transmission.

What is claimed is:  
     
       1. A method of regulating torque applied to an automotive drive train by an internal combustion engine, the engine producing the torque in accordance with a fueling rate provided to a fueling system thereof, the drive train including a transmission coupled to the engine and having a plurality of engageable gear ratios, a drive axle and a propeller shaft coupling the transmission to the drive axle, the method comprising the steps of: 
       determining a first engine fueling rate at which the resulting engine torque is limited by a maximum input torque capacity of a presently engaged gear ratio of the transmission;  
       determining a second engine fueling rate at which the resulting engine torque is limited by a maximum operating torque capacity of the propeller shaft;  
       defining an actual engine fueling rate as a minimum of said first and second engine fueling rates; and  
       fueling the engine in accordance with said actual engine fueling rate.  
     
     
       2. The method of  claim 1  further including the step of determining a third engine fueling rate at which the resulting engine torque is limited by a maximum operating torque capacity of the drive axle; 
       and wherein said defining step includes defining said actual engine fueling rate as a minimum of said first, second and third engine fueling rates.  
     
     
       3. The method of  claim 2  further including the step of performing the determining said second and third engine fueling rates steps and the defining an actual engine fueling rate step only if said presently engaged gear ratio corresponds to a lower gear ratio  of the transmission, and otherwise defining said actual engine fueling rate as said first engine fueling rate. 
     
     
       4. The method of  claim 1  further including the step of performing the determining said second engine fueling rate step and the defining an actual engine fueling rate step only if said presently engaged gear ratio corresponds to a lower gear ratio  of the transmission, and otherwise defining said actual engine fueling rate as said first engine fueling rate. 
     
     
       5. The method of  claim 1  wherein the determining a first engine fueling rate step includes the steps of: 
       sensing said presently engaged gear ratio of the transmission; and  
       determining said first engine fueling rate in accordance with said presently engaged gear ratio only if said presently engaged gear ratio indicates a valid gear ratio of the transmission.  
     
     
       6. The method of  claim 5  wherein the determining a first engine fueling rate step further includes the steps of: 
       sensing vehicle speed; and  
       determining said first engine fueling rate as a fueling rate at which the resulting engine torque is limited by a maximum input torque capacity of a lowest of the engageable transmission gear ratios if said presently engaged gear ratio indicates an invalid gear ratio of the transmission and said vehicle speed is below a predefined vehicle speed.  
     
     
       7. The method of  claim 6  wherein the determining a first engine fueling rate step further includes the step of determining said first engine fueling rate as a fueling rate at which the resulting engine torque is limited by a predefined input torque capacity of the transmission if said presently engaged gear ratio indicates an invalid gear ratio of the transmission and said vehicle speed is above said predefined vehicle speed. 
     
     
       8. A control system for regulating torque applied to an automotive drive train of a vehicle by an internal combustion engine, the drive train including a transmission coupled to the engine and having a plurality of engageable gear ratios, a drive axle and a propeller shaft coupling the transmission to the drive axle, the system comprising: 
       a fueling system associated with the engine and responsive to a fueling rate signal to provide engine output torque in accordance therewith;  
       means for determining a presently engaged gear ratio of the transmission and providing a gear ratio signal corresponding thereto; and  
       a processor responsive to said gear ratio signal to determine a first engine fueling rate signal corresponding to a fueling rate at which the resulting engine output torque is limited by a maximum input torque capacity of said presently engaged gear ratio, said processor further determining a second engine fueling rate signal corresponding to a fueling rate at which the resulting engine output torque is limited by a maximum input torque capacity of the propeller shaft, said processor providing said fueling rate signal to said fueling system as the smaller of said first and second engine fueling rate signals.  
     
     
       9. The control system of  claim 8  wherein said processor is operable to determine a third engine fueling rate signal corresponding to a fueling rate at which the resulting engine torque is limited by a maximum operating torque capacity of the drive axle; 
       and wherein said processor is further operable to to provide said fueling rate signal to said fueling system as the smaller of said first, second and third engine fueling rate signals.  
     
     
       10. The control system of clam  9  wherein said processor is operable to determine said second and third engine fueling rates and provide said fueling rate signal to said fueling system as the smaller of said first, second and third engine fueling rate signals only if said presently engaged gear ratio corresponds to a lower gear ratio  of the transmission, and otherwise defining said providing said fueling rate signal to said fueling system as said first engine fueling rate signal. 
     
     
       11. The control system of  claim 9  further including a memory unit having a plurality of fueling rate signals stored therein, said processor determining said first fueling rate signal by retrieving an appropriate one of said plurality of fueling rate signals in accordance with said presently engaged gear ratio signal. 
     
     
       12. The control system of  claim 11  wherein said maximum input torque capacity of the propeller and said maximum input torque capacity of the drive axle are stored within said memory unit; 
       and wherein said processor determines said second and third fueling rate signals by retrieving appropriate ones of said plurality of fueling rate signals in accordance with said said maximum input torque capacities of the propeller and drive axle respectively.  
     
     
       13. The control system of  claim 12  wherein said maximum input torque capacity of the propeller and said maximum input torque capacity of the drive axle are user programmable data values. 
     
     
       14. The control system of  claim 8  further including a data communications link connected to said processor, said first engine fueling rate signal provided to said processor from a remote processor via said data communications link. 
     
     
       15. A method of regulating torque applied to an automotive drive train of a vehicle by an internal combustion engine, the engine producing the torque in accordance with a fueling rate provided to a fueling system thereof, the drive train including a transmission coupled to the engine and having a plurality of engageable gear ratios, the method comprising the steps of: 
       determining a presently engaged gear ratio of the transmission;  
       setting said presently engaged gear ratio to a gear ratio of a lowest one of the gear ratios  gears of the transmission if the vehicle is stationary;  
       determining a regulated engine fueling rate at which the resulting engine torque is limited by a maximum input torque capacity of said presently engaged gear ratio of the transmission; and  
       fueling the engine in accordance with said regulated engine fueling rate.  
     
     
       16. The method of  claim 15  further including the steps of: 
       determining a default engine fueling rate at which the resulting engine torque is limited by a nominal input torque capacity of the transmission; and  
       comparing said regulated engine fueling rate to said default engine fueling rate;  
       and wherein the fueling step is conditioned upon said regulated engine fueling rate exceeding said default engine fueling rate, and otherwise fueling the engine in accordance with said default engine fueling rate.  
     
     
       17. A control system for regulating torque applied to an automotive drive train of a vehicle by an internal combustion engine, the drive train including a transmission coupled to the engine and having a plurality of engageable gear ratios, the system comprising: 
       a fueling system associated with the engine and responsive to a fueling rate signal to provide engine output torque in accordance therewith;  
       means for determining a presently engaged gear ratio of the transmission and providing a gear ratio signal corresponding thereto;  
       a vehicle speed sensor for sensing vehicle speed and producing a vehicle speed signal corresponding thereto; and  
       a processor receiving said gear ratio signal and determining validity thereof, said processor responsive to a valid gear ratio signal to determine a first engine fueling rate signal corresponding to a fueling rate at which the resulting engine output torque is limited by a maximum input torque capacity of said presently engaged gear ratio, said processor responsive to an invalid gear ratio signal and to said vehicle speed signal to determine a second engine fueling rate signal corresponding to a fueling rate at which the resulting engine output torque is limited by a maximum input torque capacity of a lowest of the engageable gear ratios  gears of the transmission if said vehicle speed signal is below a predefined vehicle speed signal level, said processor providing said fueling rate signal as one of said first and second engine fueling rate signals.  
     
     
       18. The control system of  claim 17  wherein said processor is further responsive to said invalid gear ratio signal and to said vehicle speed signal to determine a third engine fueling rate signal corresponding to a fueling rate at which the resulting engine output torque is limited by a nominal input torque capacity of the transmission if the vehicle speed signal is above said predefined vehicle speed signal level; 
       and wherein said processor further provides said fueling rate signal as one of said first, second and third engine fueling rate signals.  
     
     
       19. A method of regulating torque applied to an automotive drive train of a vehicle by an internal combustion engine, the engine producing the torque in accordance with a fueling rate provided to a fueling system thereof, the drive train including a transmission coupled to the engine and having a plurality of engageable gear ratios, the method comprising the steps of: 
       determining a default engine fueling rate at which the resulting engine torque is limited by a nominal input torque capacity of the transmission;  
       determining a presently engaged gear ratio of the transmission;  
       determining a regulated engine fueling rate at which the resulting engine torque is limited by a maximum input torque capacity of said presently engaged gear ratio of the transmission;  
       determining an acceleration value corresponding to an acceleration rate of the vehicle;  
       determining an engine power value corresponding to engine operating power;  
       defining an actual engine fueling rate as said regulated engine fueling rate if said acceleration value is less than a predefined acceleration rate and said engine power value is greater than a threshold value, and otherwise defining said actual engine fueling rate as said default engine fueling rate; and  
       fueling the engine in accordance with said actual engine fueling rate.  
     
     
       20. A control system for regulating torque applied to an automotive drive train of a vehicle by an internal combustion engine, the drive train including a transmission coupled to the engine and having a plurality of engageable gear ratios, the system comprising: 
       a fueling system associated with the engine and responsive to a fueling rate signal to provide engine output torque in accordance therewith;  
       means for determining a presently engaged gear ratio of the transmission and providing a gear ratio signal corresponding thereto;  
       an engine speed sensor for sensing engine speed and producing an engine speed signal corresponding thereto;  
       a vehicle speed sensor for sensing vehicle speed and producing a vehicle speed signal corresponding thereto; and  
       a processor responsive to said gear ratio signal to determine a first engine fueling rate signal corresponding to a fueling rate at which the resulting engine output torque is limited by a maximum input torque capacity of said presently engaged gear ratio, said processor further determining a second engine fueling rate signal corresponding to a fueling rate at which the resulting engine output torque is limited by a nominal input torque capacity of the transmission, said processor responsive to said vehicle speed signal to determine vehicle acceleration rate, and further to said engine speed signal to determine engine operating power, said processor providing said fueling rate signal as said first engine fueling rate signal if said vehicle acceleration is less than a predefined acceleration rate and said engine operating power is greater than a threshold value, and otherwise as said second engine fueling rate signal.  
     
     
       21. The control system of  claim 20  further including a memory unit having said predefined acceleration rate stored therein. 
     
     
       22. The control system of  claim 21  wherein said predefined acceleration rate stored within said memory unit is a user programmable data value. 
     
     
       23. A control system for regulating torque applied to an automotive drive train of a vehicle by an internal combustion engine, the drive train including a transmission coupled to the engine and having a plurality of engageable gear ratios, the system comprising: 
       a fueling system associated with the engine and responsive to a fueling rate signal to provide engine output torque in accordance therewith;  
       a first processor associated with the transmission, said first processor determining a presently engaged gear ratio of the transmission and producing a regulated engine fueling rate signal corresponding to a fueling rate at which the resulting engine output torque is limited by a maximum input torque capacity of said presently engaged gear ratio;  
       a second processor associated with the engine, said second processor determining a default fueling rate signal corresponding to a fueling rate at which the resulting engine output torque is limited by a nominal input torque capacity of the transmission, said second processor receiving said regulated fueling rate signal from said first processor and providing said fueling rate signal to said fueling system as the larger of said regulated fueling rate signal and said default fueling rate signal.  
     
     
       24. The control system of  claim 23  further including a data communications line connected to said first and second processors, said first processor providing said regulated fueling rate signal to said second processor via said communications link. 
     
     
       25. A control system for regulating torque applied to an automotive drive train of a vehicle by an internal combustion engine, the drive train including a transmission coupled to the engine and having a plurality of engageable gear ratios, the system comprising: 
       
         a fueling system associated with the engine and responsive to a fueling signal to provide engine output torque in accordance therewith;  
       
       
         a first processor associated with the transmission, said first processor containing a maximum input torque capacity of each of said gear ratios; and  
       
       
         a second processor associated with the engine;  
       
       
         wherein said first processor provides said maximum input torque capacities to said second processor; and  
       
       
         wherein said second processor receives said maximum input torque capacities from said first processor, produces a regulated engine fueling signal as a function of the maximum input torque capacity of a presently engaged gear ratio, and provides said regulated engine fueling signal to said fueling system.  
       
     
     
       26. The control system of  claim 25  wherein said first processor determines said presently engaged gear ratio.  
     
     
       27. The control system of  claim 26  wherein said second processor produces a default fueling signal as a function of a nominal input torque capacity of the transmission and provides the larger of said regulated fueling signal and said default fueling signal to said fueling system.  
     
     
       28. The control system of  claim 25  wherein said second processor produces a default fueling signal as a function of a nominal input torque capacity of the transmission and provides the larger of said regulated fueling signal and said default fueling signal to said fueling system.  
     
     
       29. A control system for regulating torque applied to an automotive drive train of a vehicle by an internal combustion engine, the drive train including a transmission coupled to the engine and having a plurality of engageable gear ratios, the system comprising: 
       
         a fueling system associated with the engine and responsive to a fueling signal to provide engine output torque in accordance therewith;  
       
       
         a first processor associated with the transmission, said first processor producing a regulated engine fueling rate signal as a function of the maximum input torque capacity of a presently engaged gear ratio; and  
       
       
         a second processor associated with the engine, said second processor receiving said regulated engine fueling rate signal from said first processor, converting said regulated engine fueling rate signal into a regulated fueling signal, and providing said regulated fueling signal to said fueling system.  
       
     
     
       30. The control system of  claim 29  wherein said first processor determines said presently engaged gear ratio.  
     
     
       31. The control system of  claim 30  wherein said second processor produces a default fueling signal as a function of a nominal input torque capacity of the transmission and provides the larger of said regulated fueling signal and said default fueling signal to said fueling system.  
     
     
       32. The control system of  claim 29  wherein said second processor produces a default fueling signal as a function of a nominal input torque capacity of the transmission and provides the larger of said regulated fueling signal and said default fueling signal to said fueling system.  
     
     
       33. A method of regulating torque applied to an automotive drive train by an internal combustion engine, the engine producing torque in accordance with a fueling signal provided by an engine controller to a fueling system thereof, the drive train including a transmission coupled to the engine and having a plurality of engageable gear ratios and a transmission controller, the method comprising: 
       
         storing a torque command in said transmission controller for each of said gear ratios;  
       
       
         detecting a presently engaged gear ratio;  
       
       
         transmitting the torque command corresponding to said presently engaged gear ratio from said transmission controller to said engine controller;  
       
       
         converting said torque command into a first fueling signal in said engine controller; and  
       
       
         providing said first fueling signal to said fueling system.  
       
     
     
       34. The method of  claim 33  wherein said detecting step is performed by said transmission controller.  
     
     
       35. The method of  claim 34  further comprising producing a default fueling signal as a function of a nominal input torque capacity of the transmission, and providing the larger of said first fueling signal and said default fueling signal to said fueling system.  
     
     
       36. The method of  claim 33  further comprising producing a default fueling signal as a function of a nominal input torque capacity of the transmission, and providing the larger of said first fueling signal and said default fueling signal to said fueling system.