Internal-combustion engines – Engine speed regulator – Having condition responsive means with engine being part of...
Reexamination Certificate
2000-01-31
2001-05-29
Yuen, Henry C. (Department: 3747)
Internal-combustion engines
Engine speed regulator
Having condition responsive means with engine being part of...
C123S436000, C123S399000
Reexamination Certificate
active
06237563
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention lies in the field of internal combustion engines. The invention relates to a method for controlling an internal combustion engine. In a method according to German Published, Non-Prosecuted Patent Application 42 32 974 A1, an estimated value of an ignition-angle-standardized actual torque is determined. A setpoint value of a torque that is to be set by the air mass flow rate is determined in a device for specifying torque values. The setpoint value of the torque is corrected as a function of a deviation of the setpoint value from the standardized estimated value of the torque. The corrected setpoint value of the torque is assigned to a setpoint value of the air mass flow rate as a function of the rotational speed, the value then being set by a corresponding degree of opening of a throttle valve. An ignition angle is adjusted as a function of the deviation of the setpoint value from the standardized estimated value of the torque.
If the determination of the torque setpoint value is additionally performed taking into account various torque requests, for example (1) of a traction controller, (2) of a torque derivative action for heating a catalytic converter, or (3) a torque request of an engine drag torque controller, deviations between the standardized estimated value of the torque and the setpoint value of the torque occur even during steady-state operation of the internal combustion engine. The air mass flow rate, assigned to the corrected setpoint value of the torque, in a cylinder of the internal combustion engine cannot be set until after a long delay time. Accordingly, the correction of the torque as a function of the setpoint value and of the estimated value of the torque gives rise to severe oscillations in the air mass flow rate, thus giving rise to a need for adjusting the ignition angle. Such adjustment results in a reduction of driving comfort and an increase in emissions.
A method for setting the torque on an internal combustion engine is disclosed in German Patent No. 43 15 885 C1. A regulator having the air mass flow rate as the controlled variable is provided and generates an actuation signal for a throttle valve. The system deviation of the regulator is formed from an average air mass flow rate, which is calculated using an inversely clocked load filter as a function of a predefined load setpoint value, and a measured air mass flow rate.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method for controlling an internal combustion engine that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type, that is precise and, at the same time, has good step-value characteristics with respect to torque step-values over the entire operating time of the internal combustion engine.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a method for controlling an internal combustion engine, including the steps of determining a measured value of an actual torque that is being output to an output shaft of an internal combustion engine, determining an estimated value of the actual torque as a function of operating variables of the internal combustion engine, adapting a predefined correction value as a function of the estimated value of the actual torque and of the measured value of the actual torque, setting a setpoint value of the torque by an air mass flow rate as a function of a pedal position that is determined by a pedal position sensor and is calculated by at least one further operating variable, correcting the setpoint value of the torque as a function of the correction value, and determining an actuator signal for an actuator element of the internal combustion engine as a function of the corrected setpoint value of the torque.
In accordance with another mode of the invention, there is provided the step of correcting the estimated value of the actual torque as a function of the correction value.
In accordance with a further mode of the invention, there is provided the step of actuating an emergency operating mode of the internal combustion engine if a deviation of the estimated value of the actual torque from the measured value of the actual torque is greater than a predefined threshold value.
In accordance with an added mode of the invention, there is provided the step of actuating an emergency operating mode of the internal combustion engine if a time integral over a deviation of the estimated value of the actual torque from the measured value of the actual torque is greater than a predefined threshold value.
In accordance with an additional mode of the invention, the actuating step of the emergency operating mode is performed by limiting a rotational speed of a crankshaft.
In accordance with yet another mode of the invention, there is provided the step of calculating the correction value as a function of a rotational speed and of the air mass flow rate into a cylinder of the internal combustion engine by filtering the deviation of the estimated value of the actual torque from the measured value of the actual torque.
In accordance with yet a further mode of the invention, there is provided the step of determining the estimated value of the actual torque as a function of an ignition-angle efficiency value, an air/fuel ratio efficiency value and a reference value of the torque, the reference value of the torque depending on the air mass flow rate into the cylinder and on a rotational speed.
In accordance with yet an added mode of the invention, there is provided the step of additionally determining the estimated value of the actual torque as a function of a cylinder shut-off efficiency value.
In one advantageous refinement of the invention, an observer is provided that determines an air mass flow rate into a cylinder of the internal combustion engine as a function of a measured air mass flow rate. The observer includes a dynamic filling model of the intake tract of the internal combustion engine.
In accordance with yet an additional mode of the invention, there is provided the step of determining the air mass flow rate by an observer as a function of a measured air mass flow rate.
In accordance with a concomitant mode of the invention, the determining an actuator signal step is performed by determining an actuator signal for a throttle valve of the internal combustion engine.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method for controlling an internal combustion engine, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
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Japanese Patent Abstract No. 60001375 (Toshiharu), dated Jan. 7, 1985.
Froehlich Johann
Treinies Stefan
Zhang Hong
Gimie Mahmoud M
Greenberg Laurence A.
Lerner Herbert L.
Siemens Aktiengesellschaft
Stemer Werner H.
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