| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce vibration noise (NVH) level by reducing an in-cylinder pressure rise rate during combustion when performing self-ignition combustion of fuel injected into a cylinder. <P>SOLUTION: This direct injection gasoline engine is provided with an ignition assist means which imparts energy to fuel injected into a cylinder by an injector and assists the self-ignition combustion of the fuel when the engine is in a self-ignition combustion operating region. When the engine is in the self-ignition combustion operating region, fuel injection start timing is set within a period from a terminal period of a compression stroke to a compression top dead center. The ignition assist means is configured so that energy is imparted to the fuel injected into the cylinder during the period after the start of the fuel injection until the initial period of an expansion stroke such that a crank angle time point at which the maximum negative value of an in-cylinder pressure rise rate is achieved, which is the change in the in-cylinder pressure with respect to the change in the crank angle during engine motoring, overlaps the combustion period wherein a fuel combustion mass fraction is 10% or more and 90% or less. <P>COPYRIGHT: (C)2013,JPO&INPIT |
