Patent ID: 8151762
Filing Date: 2012-04-10
Classification: F02B,Y02T

Abstract:
1. A direct-injection spark-ignition engine comprising: a multi-hole injector adapted to inject a plurality of fuel sprays obliquely downwardly from a peripheral position of a roof wall surface defining a combustion chamber, a spark plug disposed at a center of the combustion chamber-defining roof wall surface, and a concave cavity provided in a central region of a piston crown surface of a piston located in opposed relation to the spark plug, wherein: the injector has at least two spray holes consisting of a first spray hole adapted to form a first fuel spray to, after being injected, directly enter the cavity at a given timing in a later period of a compression stroke, and a second spray hole adapted to form a second fuel spray to be located below the first fuel spray, and wherein a timing of fuel injection from the injector during cold engine operation is set to allow the first fuel spray to be turned toward the combustion chamber-defining roof wall surface after entering the cavity, and allow the second fuel spray to impinge against a region of the piston crown surface located closer to the injector than the cavity, to cause the second fuel spray having a lowered penetration force due to the impingement to be pulled toward the cavity by a negative pressure generated in the cavity as a result of passing of the first fuel spray therethrough, and held around the spark plug.