| 摘要 |
PURPOSE:To prevent generation of a knock in a 4-cycle engine, provided with two spark plugs in a cylinder, at high load and low speed operation when the engine is accelerated. CONSTITUTION:Another end of a small controlled communication passage 38, connected with one end to an intake air storage chamber 36, is opened to an intake passage 28, and this opening is so positioned as to be directed to the direction of a high temperature part in the vicinity of an exhaust valve 18 at opening time of an intake valve 16. That is, an area, in the vicinity of a place A in the peripheral edge of the exhaust valve 18 in a cylinder internal wall side, becomes the highest temperature in a combustion chamber 20 and is cooled by the intake air. Accordingly, at high load and low speed operation of an engine when the engine is rapidly accelerated, a flame propagation speed is increased by reduction of residual gas, even if internal pressure in the combustion chamber 20 is rapidly increased, the high temperature part A is not excessively increased its temperature, and gas performs combustion by regular flames ignited by spark plugs 22, 24. |
