Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – With indicator or control of power plant
Reexamination Certificate
1999-05-06
2001-06-12
Wolfe, Willis R. (Department: 3747)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
With indicator or control of power plant
C701S115000
Reexamination Certificate
active
06246951
ABSTRACT:
TECHNICAL FIELD
The present invention is directed to a system and method for interpreting driver demand to control an engine.
BACKGROUND ART
Control strategies for internal combustion engines have evolved from purely electromechanical strategies to increasingly more complex electronic or computer controlled strategies. Spark-ignited internal combustion engines have traditionally used airflow as the primary control parameter, controlled by a mechanical linkage between a throttle valve and an accelerator pedal. Fuel quantity and ignition timing, originally mechanically controlled, were migrated to electronic control to improve fuel economy, emissions, and overall engine performance. Electronic airflow control systems including electronic throttle, variable cam timing, and the like, have been developed to further improve the authority of the engine controller resulting in even better engine performance.
Electronic throttle control replaces the traditional mechanical linkage between the accelerator pedal and the throttle valve with an “electronic” linkage through the engine or powertrain controller. Because of this electrical or electronic linkage, this type of strategy is often referred to as a “drive by wire” system. A sensor is used to determine the position of the accelerator pedal which is input to the controller. The controller determines the required airflow and sends a signal to a servo motor which controls the opening of the throttle valve. Control strategies which imitate the mechanical throttle system by controlling the opening of the throttle valve based primarily on the position of the accelerator pedal position are often referred to as pedal follower systems. However, the ability of the controller to adjust the throttle valve position independently of the accelerator pedal position offers a number of potential advantages in terms of emissions, fuel economy, and overall performance.
The driver controls output of the engine or powertrain primarily based on the position of the accelerator pedal. The engine control strategy must interpret this driver demand and set the appropriate engine control parameters to provide a corresponding powertrain output. The driver demand may be interpreted as a request for a particular throttle angle (pedal follower system), an engine torque, a wheel torque, or power (torque*speed). To achieve a consistent driver “feel”, many prior art control strategies attempt to provide a constant powertrain output for a particular accelerator pedal position, regardless of the current operating conditions, such as barometric pressure. While these strategies consider the current operating conditions, such as barometric pressure, in determining the control parameters for the engine, the operating conditions are used to maintain a constant output independent of the operating conditions. However, this strategy may result in unsatisfactory performance when the available engine power is reduced, such as when driving at high altitude (low barometric pressure).
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a system and method for controlling an internal combustion engine which compensates for variations in barometric pressure when interpreting the driver demand for requested powertrain output. As such, the present invention modifies the driver request for powertrain output based upon the currently available powertrain output which varies as a function of barometric pressure.
In carrying out the above object and other objects, advantages, and features of the present invention, a system and method for controlling a vehicular powertrain including an internal combustion engine to compensate for variation in currently available powertrain output include modifying a driver request for powertrain output based upon the currently available powertrain output. In one embodiment of the invention, the system and method include determining an accelerator pedal position, generating a signal indicative of current speed, generating a signal indicative of driver requested powertrain output based on the accelerator pedal position and the current speed, and determining a value indicative of current barometric pressure. The reference powertrain output parameter is then modified based on the current barometric pressure and used to control the powertrain output. Powertrain output may be determined using any number of parameters, such as engine torque or power, wheel torque or power, tractive effort, etc. Likewise, the current speed may represent engine speed, vehicle speed, wheel speed, etc.
The present invention provides a number of advantages over prior art control strategies. For example, by adjusting the base driver demanded torque in response to barometric pressure, full accelerator pedal travel is preserved and “dead pedal” feel is eliminated when operating the vehicle at high altitudes. As such, according to the present invention, the accelerator pedal position is interpreted as a request for a portion or percentage of the currently available engine torque or power which varies as a function of the barometric pressure.
The above advantages and other advantages, objects and features of the present invention will be readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.
REFERENCES:
patent: 4353272 (1982-10-01), Schneider et al.
patent: 4697561 (1987-10-01), Citron
patent: 4730708 (1988-03-01), Hamano et al.
patent: 4739483 (1988-04-01), Ina et al.
patent: 4819596 (1989-04-01), Yasuoka et al
patent: 4943921 (1990-07-01), Baltusis et al.
patent: 4951627 (1990-08-01), Watanbe et al.
patent: 5069181 (1991-12-01), Togai et al.
patent: 5078109 (1992-01-01), Yoshida et al.
patent: 5086668 (1992-02-01), Fujiwara et al.
patent: 5109732 (1992-05-01), Takizawa
patent: 5245966 (1993-09-01), Zhang et al.
patent: 5284116 (1994-02-01), Richeson, Jr.
patent: 5304102 (1994-04-01), Narita et al.
patent: 5325740 (1994-07-01), Zhang et al.
patent: 5351776 (1994-10-01), Keller et al.
patent: 5374224 (1994-12-01), Huffmaster et al.
patent: 5398544 (1995-03-01), Lipinski et al.
patent: 5407401 (1995-04-01), Bullmer et al.
patent: 5408966 (1995-04-01), Lipinski et al.
patent: 5408974 (1995-04-01), Lipinski et al.
patent: 5431139 (1995-07-01), Grutter et al.
patent: 5437253 (1995-08-01), Huffmaster et al.
patent: 5462501 (1995-10-01), Bullmer et al.
patent: 5484351 (1996-01-01), Zhang et al.
patent: 5501644 (1996-03-01), Zhang
patent: 5503129 (1996-04-01), Robichaux et al.
patent: 5520159 (1996-05-01), Pao et al.
patent: 5568795 (1996-10-01), Robichaux et al.
patent: 5575257 (1996-11-01), Lange et al.
patent: 5588178 (1996-12-01), Liu
patent: 5603672 (1997-02-01), Zhang
patent: 5605131 (1997-02-01), Ohno et al.
patent: 5606951 (1997-03-01), Southern et al.
patent: 5628706 (1997-05-01), Zhang et al.
patent: 5680763 (1997-10-01), Unland et al.
patent: 5692471 (1997-12-01), Zhang
patent: 5743083 (1998-04-01), Schnaibel et al.
patent: 6029624 (2000-02-01), Beechie et al.
patent: 66831/81 (1982-09-01), None
patent: 0 206 091 B1 (1986-12-01), None
patent: 0 340 764 (1989-11-01), None
patent: 0 408 767 B1 (1991-01-01), None
patent: 0 413 031 B1 (1991-02-01), None
patent: 0 557 299 B1 (1991-10-01), None
patent: 0 749 524 B1 (1995-02-01), None
patent: 0 754 888 A2 (1997-01-01), None
patent: 2 154 763 (1985-09-01), None
patent: 2 239 500 (1991-07-01), None
patent: 2 239 683 (1991-07-01), None
patent: WO 95/01502 (1995-01-01), None
“Hierarchial Control Strategy of Powertrain Functions”, by H.M. Streib et al, 24. FISITA Congress, London Jun. 7-11, 1992, pp. 1-11.
“Torque-Based System Structure of the Electronic Engine Management System (ME7) as a New Base for Drive Train Systems”, by J. Gerhardt et al, 6. Aachener Kolloquim Fahrzeug- und Motorentechnik '97, Oct. 22, 1997, pp. 817-849.
Pallett Tobias John
Robichaux Jerry Dean
Ford Global Technologies Inc.
Lippa Allan J.
Wolfe Willis R.
LandOfFree
Torque based driver demand interpretation with barometric... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Torque based driver demand interpretation with barometric..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Torque based driver demand interpretation with barometric... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2454962