| 摘要 |
PROBLEM TO BE SOLVED: To eliminate torque steps accompanied by the switching between an output-oriented cam and a fuel efficiency-oriented cam for supposing different inlet negative pressures. SOLUTION: When a request for switching from the output-oriented cam to the fuel efficiency-oriented cam is generated, a target throttle valve travel is increased with an inlet negative pressure for achieving equal torque in the fuel efficiency-oriented cam as a target. Since operation is being made by the output-oriented cam in this state, the throttle valve travel required for obtaining a target inlet negative pressure is larger as compared with a case after switching to the fuel efficiency-oriented cam. As a result, the inlet negative pressure gradually decreases and approaches atmospheric pressure. Meanwhile, the amount of air becomes excessive, so that an ignition period is retarded to maintain the equal torque. Cam switching is executed after a lapse ofΔt time where the target inlet negative pressure is reached. In this state, since the target inlet negative pressure is reached, no torque steps are generated. COPYRIGHT: (C)2004,JPO
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