Control device of spark-ignition gasoline engine

Abstract

The disclosure provides a control device of a spark-ignition gasoline engine. According to the invention, in a spark-ignition gasoline engine (1) with a higher high compression ratio, abnormal burning in a high load area can be avoided. When an operating state of an engine body is within a low engine speed range, a controller (PCM 10) operates a fuel pressure variable mechanism (a high pressure fuel supply system 62) so that a fuel pressure is higher within a high engine load range compared to a low engine load range, the controller operates, within the high engine load range, a fuel injection mechanism to perform at least a fuel injection into the cylinder by a cylinder internal injection valve (a straight spray injector 67) at a timing during a retard period from a late stage of a compression stroke to an early stage of an expansion stroke, and the controller (10) operates, within the high engine load range, an ignition plug to ignite at a timing during the retard period and after the fuel injection.

Description

technical field [0001] The technology disclosed herein relates to control devices for spark ignition gasoline engines. Background technique [0002] In improving the theoretical thermal efficiency of spark ignition gasoline engine, increasing its geometric compression ratio is an effective method. For example, Patent Document 1 describes a spark ignition direct injection engine having a geometric compression ratio of 14 or higher and a high compression ratio. [0003] Also, as described in Patent Document 2, for example, as a technique capable of achieving both improvement of exhaust emissions and improvement of thermal efficiency, a combustion method of compression-igniting lean mixture gas is known. In an engine that performs such compression ignition combustion, increasing the geometric compression ratio contributes to the stabilization of compression ignition combustion by increasing the compression end pressure and the compression end temperature. [0004] Patent Docu...

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Problems solved by technology

However, an engine whose geometric compression ratio is set relatively high for the purpose of stabilizing compression ignition combustion may cause abnormal combustion similarly to the engine of Patent Document 1 in the high-load operating region where spark ignition combustion is performed. question

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