Internal-combustion engines – Engine speed regulator – Idle speed control
Reexamination Certificate
1999-08-27
2001-06-26
Yuen, Henry C. (Department: 3747)
Internal-combustion engines
Engine speed regulator
Idle speed control
C123S339190, C123S339210, C123S352000
Reexamination Certificate
active
06250282
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an idle rotation speed learning control method and apparatus of an electronically controlled throttle type internal combustion engine. More particularly, the present invention relates to a method and apparatus for learning and correcting a target opening of a throttle valve at the time of idling, in an internal combustion engine having an electronically controlled throttle system for electronically controlling the opening of the throttle valve.
2. Description of the Related Art
Heretofore, there is known an electronically controlled throttle system where the throttle valve is opened and closed by an actuator such as a motor or the like, and a target air quantity is set based on an accelerator operation amount, and the opening of the throttle valve is electronically controlled to an opening giving the target air quantity.
Moreover, there is known a construction where, at the time of idling the engine, while feedback controlling the intake air quantity of the engine so that the engine rotation speed approaches a target idle rotation speed, when predetermined learning conditions materialized, the air quantity due to the feedback correction is learned as a fluctuation amount of a required intake air quantity due to friction of the engine or variations in the combustion efficiency, and a change amount in an opening area with lapse of time due to soiling or blocking of an intake system or deterioration or replacement of other parts, or the like. The intake air quantity and the target opening of the throttle valve are then corrected based on the learned values.
With the system as described above however, which collectively learns the fluctuation amount of the required intake air quantity and the change amount in the opening area only by the feedback control of the engine rotation speed at the idling time, the learning accuracy cannot be increased sufficiently. That is to say, with the above method, a discrepancy between a detection value of the throttle valve opening and the actual opening cannot be learned, and only the discrepancy of the detection value of the throttle valve opening with respect to the fluctuation amount of the required intake air quantity and the change amount in the opening area can be learned. Hence, the target opening of the throttle valve cannot be corrected sufficiently accurately in response to a required engine output.
The present invention addresses the above problems with the object of effecting control in an internal combustion engine comprising an electronically controlled throttle system, which makes the opening of the throttle valve correspond very accurately to the required engine output.
Moreover, it is another object of the present invention to effect control which makes the opening of the throttle valve correspond very accurately to the required engine output over a long period of time.
It is a further object of the present invention to be able to avoid the influence of programming bugs.
SUMMARY OF THE INVENTION
Therefore, an idle rotation speed learning control method of an electronically controlled throttle type internal combustion engine according to the present invention comprises the steps of:
setting a target opening of a throttle valve according to a required output of an engine, and opening and closing the throttle valve with an actuator so as to obtain the target opening;
performing air quantity learning for learning and correcting the target opening of the throttle valve so as to obtain a target intake air quantity, by estimating an intake air quantity based on a detection value of the throttle valve opening and comparing the estimated intake air quantity and an actually detected intake air quantity, at the time of idling the engine; and
after completion of the air quantity learning, performing friction learning for learning and correcting the target opening of the throttle valve so as to obtain a target engine output, while feedback controlling the throttle valve opening so that the engine rotation speed approaches a target idle rotation speed, at the time of idling the engine.
Furthermore, an idle rotation speed learning control apparatus of an electronically controlled throttle type internal combustion engine according to the present invention comprises:
a target opening setting device for setting a target opening of a throttle valve according to a required output of an engine;
a throttle valve drive device for opening and closing the throttle valve with an actuator so as to obtain the target opening;
an air quantity learning device for learning and correcting the target opening of the throttle valve so as to obtain a target intake air quantity, by comparing an intake air quantity estimated based on a detection value of the throttle valve opening and an actually detected intake air quantity, at the time of idling the engine;
a friction learning device for learning and correcting the target opening of the throttle valve so as to obtain a target engine output, while feedback controlling the throttle valve opening so that the engine rotation speed approaches a target idle rotation speed, at the time of idling the engine; and
a learning sequence device for performing learning by means of the friction learning device, after learning by means of the air quantity learning device is completed.
According to the method and apparatus of the present invention, after the target opening of the throttle valve is learned and corrected so as to obtain the target intake air quantity, the target opening of the throttle valve is learned and corrected so as to obtain the target engine output.
Therefore, after the target opening is learned and corrected with respect to a change amount in the opening area with the lapse of time due to soiling or blocking of the throttle valve, for the deviation between the detection value of the throttle valve opening and the actual opening, the target opening is learned and corrected with respect to variations of friction or combustion efficiency. Hence, it is possible to effect control which makes the throttle valve opening correspond very accurately to the required engine output, over a long period of time.
Moreover, the air quantity learning may involve calculating a correction amount for a detection value of the throttle valve opening so that the intake air quantity estimated based on the detection value of the throttle valve opening and a detection value of the engine rotation speed becomes equal to the actually detected intake air quantity, and correcting the target opening of the throttle valve based on the correction amount.
In this way, the correction amount for the detection value of the throttle valve opening is calculated so that the intake air quantity estimated based on the detection value of the throttle valve opening and the detection value of the engine rotation speed becomes equal to the actual intake air quantity detected by an airflow meter or the like. By correcting the target opening of the throttle valve according to the correction amount, a target intake air quantity corresponding to the target opening can be obtained.
Furthermore, the correction amount calculated by the air quantity learning may be limited by a limit value.
In this way, the possibility of the correction amount calculated by the air quantity learning becoming an excessive value due to some cause such as a programming bug, is prevented by limiting with the limit value.
Furthermore, the air quantity learning may judge the time when more than a predetermined number of learning are performed as completion of the air quantity learning.
In this way, the friction learning can be started, after the air quantity learning is sufficiently performed to obtain a high accurate learning value of the air quantity.
Moreover, the friction learning may involve calculating the friction learning value based on an average value obtained by sampling the feedback correction quantity of the intake air quantity for a plurality of times for every predetermined sampling per
Hosoya Hajime
Kakizaki Shigeaki
Katoh Hiroshi
Matsumoto Mikio
Osaki Hiroyuki
McDermott & Will & Emery
Unisia Jecs Corporation
Vo Hieu T.
Yuen Henry C.
LandOfFree
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