Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Transmission control
Reexamination Certificate
2001-07-23
2003-06-24
Black, Thomas G. (Department: 3663)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Transmission control
C477S115000, C123S406230, C123S406240, C123S406460, C475S125000
Reexamination Certificate
active
06584391
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a system and method for real time calculation of the net torque output of an internal combustion engine. The invention is useful in the operation of diesel engines that power automotive vehicles such as trucks.
BACKGROUND AND SUMMARY OF THE INVENTION
An automotive vehicle, such as a medium or heavy truck that is powered by a diesel engine, may comprise an electronic engine control that exercises control over certain aspects of engine operation. The ability of such an engine to perform in a desired manner may at times depend on its ability to meet certain torque demands. Hence, data that accurately calculates, in real time, the net torque being produced by a running engine is an important consideration in strategies for controlling engine and/or vehicle operation.
This invention relates to a system and method for real time calculation of the net torque output of an internal combustion engine. The invention is useful in the operation of diesel engines that power automotive vehicles such as trucks.
In a diesel engine net torque output is dependent on engine speed and fueling. It is also a function of other variables such as mass air and losses resulting from running of the engine. Certain constraints that are inherent in a microprocessor-based engine control, such as data storage capacity, data access speed, and data processing speed, may not allow processing of certain variable parameter data and engine model data sufficiently fast to provide sufficiently accurate real-time torque estimate suitable for control purposes.
The present invention endows an electronic engine control with an ability to develop engine net torque output data that correlates reasonably accurately in real time with the actual net torque output of a running engine. An ability to accurately develop accurate data in real time is believed to afford engine designers more and better opportunities for closer control of certain engine and/or vehicle functions. For example, accurate real-time engine net output torque data may be used to provide better definition for transmission shift points, particularly automatic transmission shift points. Such data may also be a useful input to a vehicle traction control system. It may also serve as a useful diagnostic or maintenance tool.
A diesel engine may also be modeled using certain engine-related parameters, most, if not all, of which are variables. Mean torque developed by an engine is primarily a function of fuel injected into its cylinders for combustion, but is also influenced by other factors some of which are measured and others of which are unmeasured. Such influences include, for example, fuel injection timing, engine speed, cylinder wall temperature, air-fuel ratio, intake pressure, intake temperature, fuel cetane number, fuel injection pressure, etc.
Accordingly, it is believed that in order to create an electronic engine control that is both practical to implement and capable of providing reasonably accurate torque measurement in real time, various factors must be reconciled. For example, a system and method that perhaps possesses a somewhat lesser degree of accuracy may nonetheless be acceptable if it does not have to be re-calibrated should the engine EGR rates be changed.
For developing a calculation of real-time net torque output of a running engine, meaning the torque that is present at the output of the engine for operating the drivetrain to propel vehicle, certain torques must be subtracted as losses from a base (gross) torque calculation. Such losses include accessory torques, like those required to operate an air conditioner compressor and cooling fan, and pumping torques, like those required to operate a pump that pressurizes hydraulic fluid for operating various devices on the engine such as high-pressure fuel injectors and those that are inherent in the pumping action of the internal mechanism of the engine. Torque lost due to mechanical friction is another subtraction from gross torque production of a running engine.
Certain transient changes that occur during running of an engine in a motor vehicle have transient effects on gross and net torque, and so it may also be appropriate to take them into account when calculating torques.
One aspect of the present invention relates to accounting for certain transient effects.
Other aspects of the invention relate to compensation for losses such as those described above.
A general aspect of the invention relates to a torque calculation method for providing real time data that measures net torque output of a running engine at a rotating member of the engine.
The method comprises: processing data that includes engine speed data and engine fueling data to create engine gross torque data for the running engine; processing data related to torque losses due to running of the engine to create engine running torque loss data; processing engine speed data to create engine acceleration and deceleration data; and processing the engine acceleration and deceleration data with data defining a moment of inertia attributable to the rotating member and engine mechanism coupled to that member to create data measuring inertial torque.
The inertial torque data is algebraically added to, and the engine running torque loss data is subtracted from, the engine gross torque data to create engine net running torque data. The engine net running torque data and engine speed data are processed according to a filter algorithm that compensates the engine net running torque data for engine speed.
Another aspect relates to an operating system that embodies the general method just described.
Still another aspect relates to a motor vehicle embodying a method and operating system as described where transmission shifting is controlled by the speed-compensated engine net running torque data.
The foregoing, along with further features and advantages of the invention, will be seen in the following disclosure of a presently preferred embodiment of the invention depicting the best mode contemplated at this time for carrying out the invention. The disclosure includes accompanying drawings, briefly described as follows.
REFERENCES:
patent: 5484351 (1996-01-01), Zhang et al.
patent: 5509867 (1996-04-01), Genise
patent: 6035252 (2000-03-01), Dixon et al.
Black Thomas G.
Calfa Jeffrey P.
International Engine Intellectual Property Company LLC
Lukasik Susan L.
Sullivan Dennis Kelly
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