PREMIXING COMPRESSION IGNITION TYPE ENGINE

To provide a premixing compression ignition type engine capable of reducing combustion noise while securing high heat efficiency.SOLUTION: In a premixing compression ignition type engine capable of self-igniting a mixture gas of fuel and air including gasoline in a combustion chamber 6, water injection means 15 for injecting water, is disposed in the combustion chamber 6. The water injection means 15 is allowed to inject water to an intermediate portion R3 positioned between an outer peripheral portion R2 in a radial direction of the combustion chamber 6 and an inner peripheral portion R1 separated to an inner side in a radial direction from the outer peripheral portion R2, in a second half of a compression stroke or a first half of an expansion stroke before start of a high-temperature oxidation reaction of the air-fuel mixture in the combustion chamber 6 in operation by the self-ignition combustion.SELECTED DRAWING: Figure 11 【課題】高い熱効率を確保しつつ燃焼騒音を低減可能な予混合圧縮着火式エンジンを提供する。【解決手段】燃焼室６内でガソリンを含有する燃料と空気との混合気を自着火させることが可能な予混合圧縮着火式エンジンにおいて、燃焼室６内に水を噴射する水噴射手段１５を設ける。水噴射手段１５に、自着火燃焼による運転時において、圧縮行程後期あるいは膨張行程前期で且つ燃焼室６内で混合気の高温酸化反応が開始するよりも前に、燃焼室６の径方向の外周部Ｒ２と当該外周部Ｒ２から径方向の内側に離れた内周部Ｒ１との間に位置する中間部Ｒ３に水を噴射させる。【選択図】図１１