| 摘要 |
PROBLEM TO BE SOLVED: To heat the air sucked in a diesel engine by a novel method. SOLUTION: An air intake valve 11 to connect/disconnect a combustion chamber 6 to/from an air intake port 8 is arranged in an engine 1, and the opening/closing timing of the air intake valve 11 is adjusted by a valve driving mechanism 20. A CPU 50a in an ECU 50 judges presence/absence of the request for heating the sucked air based on the water temperature Tw to be detected by a water temperature sensor 51, and the heating of the sucked air is requested, the drive of the valve driving mechanism 20 is controlled so that the air intake valve 11 is opened between the piston position of TDC to BDC in the intake stroke. The air intake characteristic by the air intake valve 11 is delayed to generate the vacuum pressure in the combustion chamber 6 as a piston 4 is lowered. The energy (the pump loss) in generating the vacuum pressure is transferred to the fresh air as the heat energy. As a result, the temperature of the in-cylinder gas in the compression stroke following the intake stroke rises, the ignition property of the fuel is improved, and the combustion condition is also improved. |
