Intake air amount control apparatus and intake air amount control method for internal combustion engine

Abstract

A plurality of changing mechanisms change the manner in which intake air is supplied to an internal combustion engine. A control unit executes a cooperative control in which, based on the driving state of one of a variable vale lift mechanism and at least one of the other changing mechanisms other than the variable valve lift mechanism, the driving state of the other one of the variable valve lift mechanism and the at least one of the changing mechanisms is controlled. A determining unit determines whether the operational response of the changing mechanisms is decreased. A restricting unit restricts the cooperative control when the determining unit determines that the operational response of at least one of the changing mechanisms is decreased. Therefore, disadvantages caused by reduction in the operational response of the changing mechanisms are reduced.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates to an intake air amount control apparatus for an internal combustion engine that is equipped with changing mechanisms that change the manner in which intake air is supplied to the internal combustion engine. The present invention also pertains to an intake air amount control method for the internal combustion engine. [0002] In the internal combustion engine, the intake air amount is generally regulated by selectively opening and closing a throttle valve and is controlled in accordance with the operating state of the engine. Also known is an intake air amount control apparatus that changes the valve timing of intake valves (also the valve timing of exhaust valves in some cases) in addition to the throttle valve (for example, Japanese Laid-Open Patent Publication No. 2003-314308). An internal combustion engine has also been proposed that is equipped with a variable valve lift mechanism that changes the maximum lift of th...

AI Technical Summary

Benefits of technology

[0005] Accordingly, it is an objective of the present invention to provide an intake air amount control apparatus of an internal combustion engine that is equipped with changing mechanisms that change the manner in which intake air is supplied to the internal combustion engine, and to reduce disadvantages caused by reduction in the operational response of the changing mechanisms such as decrease in the engine output and occurrence of a stall. A further aspect of the present invention is to provide an intake air amount control method for the internal combustion engine.

Problems solved by technology

However, with the intake air amount control apparatus that executes such a cooperative control, the following disadvantages may occur.

That is, when the operational response of a changing mechanism other than the variable valve lift mechanism is reduced for some reason, the variable valve lift mechanism may be driven assuming that the operational response has not been reduced, or the variable valve lift mechanism may be driven in accordance with the reduction of the operational response, which may cause the maximum lift of the intake valves to be undesirably set to too small a value or too large a value.

In particular, when the maximum lift of the intake valves is set to too small a value, the engine output is significantly decreased and a stall occurs, thus hindering stable operation of the engine.

Images