| abstract |
An object of the present invention is to improve fuel economy before completion of warm-up and to avoid knocking after completion of warm-up. An electronic control unit (ECU) 50 controls a flow path change valve 64 according to an operating state of an engine 1 to thereby detect outside air from an outside air inlet 4a, high temperature air or outside air from a high temperature air passage 63, and the like. The temperature of the intake air introduced into the engine 1 is controlled by selectively flowing the mixed air with the high temperature air downstream of the intake passage 4. The ECU 50 calculates the MBT ignition timing and the knock limit ignition timing based on the detection results of the intake temperature sensor 47, the rotation speed sensor 44, and the intake pressure sensor 48, and the knock limit ignition timing is advanced from the MBT ignition timing. Introduces high-temperature air or mixed air into the engine 1 as intake air, and if the knock limit ignition timing is the same as the MBT ignition timing or is retarded from the MBT ignition timing, the engine 1 is allowed to introduce outside air as intake air. The path change valve 64 is controlled. [Selection] Figure 1 |