| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable valve gear capable of improving torque response by a supercharger further in a transient operation of an engine such as quick acceleration. SOLUTION: When it is judged that accelerator openingθis larger than predetermined openingθ0 in step 2, throttle valve openingαis controlled to the maximum opening in step 3, operation angle of a suction valve is expanded to control open timing to advanced side and to control close timing to retarded side in step 4. Since throttle valve opening is large even when accelerator openingθis small, great amount of fresh air flows into a combustion chamber without movement delay of fresh air in a suction pipe when operation angle of the suction valve is expanded. Consequently, initial response of torque in an early stage of supercharging is greatly improved. Since advancing control is executed and exhaust blow down energy increases to raise exhaust gas pressure in step 5, rotation speed of an exhaust gas turbine wheel quickly raises. COPYRIGHT: (C)2008,JPO&INPIT
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