Patent ID: 6390063
Filing Date: 2002-05-21
Classification: F01L,F02D,Y02T

Abstract:
An intake-air quantity control apparatus for an internal combustion engine with a variable valve timing system comprising:a throttle valve disposed in an intake-air passage of the engine and controlled so that a throttle opening of said throttle valve is brought closer to a target throttle opening (tTVO); an intake valve disposed between the intake-air passage and a combustion chamber of the engine and controlled so that an intake-valve closure timing of said intake valve is brought close to a target intake-valve closure timing (tIVC); and a microprocessor programmed to perform the following: (a) selecting one of a first control mode in which an intake-air quantity of the engine is controlled by adjusting the throttle opening of said throttle valve, and a second control mode in which an intake-air quantity of the engine is controlled by adjusting the intake-valve closure timing of said intake valve; (b) calculating a steady-state target engine torque (stTe) based on operating conditions (APS, Ne) of the engine, the steady-state target engine torque (stTe) indicating a steady-state target value of engine torque; (c) calculating a target engine torque (tTe) based on the steady-state target engine torque (stTe), the target engine torque (tTe) following the steady-state target engine torque (stTe) with a predetermined time delay; (d) setting a steady-state target intake-valve closure timing (stIVC) at a basic intake-valve closure timing (IVCb) when the first control mode is selected, the steady-state target intake-valve closure timing (stIVC) indicating a steady-state target value of the intake-valve closure timing; (e) calculating a steady-state target intake-air-passage internal pressure (stP) based on both the steady-state target engine torque (stTe) and the steady-state target intake-valve closure timing (stIVC) when the first control mode is selected, the steady-state target intake-air-passage internal pressure (stP) indicating a steady-state target value of an internal pressure in the intake-air passage; (f) setting the steady-state target intake-air-passage internal pressure (stP) at a basic pressure (Pb) when the second control mode is selected; (g) calculating the steady-state target intake-valve closure timing (stIVC) based on both the target engine torque (tTe) and the steady-state target intake-air-passage internal pressure (stP) when the second control mode is selected; (h) obtaining a real intake-air-passage internal pressure (rP), the real intake-air-passage internal pressure (rP) indicating an actual internal pressure in the intake-air passage; (i) calculating the target throttle opening (tTVO) based on both the steady-state target intake-valve closure timing (stIVC) and the steady-state target intake-air-passage internal pressure (stP); and (j) calculating the target intake-valve closure timing (tIVC) based on both the target engine torque (tTe) and the real intake-air-passage internal pressure (rP).