Spark-ignition direct injection engine

Abstract

A spark-ignition direct injection engine is provided. A controller (10) sets the fuel pressure to 30 MPa or above when an engine main body (1) runs within a specific part, including a boundary of a first range and a second range and high in load, of the first range, and drives a fuel injection valve (67) to inject fuel into a cylinder in a period at least from a late stage of compression stroke to an early stage of expansion stroke, such that the compression ignition is started after a compression top dead center. Moreover, When the engine main body (1) runs within a range, lower than the specific part in load, in the first range, the controller drives the fuel injection valve (67) to inject the fuel into the cylinder in a period at least from intake stroke to a mid-stage of the compression stroke.

Description

technical field [0001] The technology disclosed herein relates to spark ignition direct injection engines. Background technique [0002] For example, as described in Patent Document 1, as a technique for achieving both improvement of exhaust emission performance and improvement of thermal efficiency, a combustion form in which air-fuel mixture in a cylinder is compressed and ignited is known. In an engine that performs such compression ignition combustion, as the engine load increases, the compression ignition combustion becomes combustion in which the pressure rises sharply, leading to an increase in combustion noise. Therefore, as described in Patent Document 1, even an engine that performs compression ignition combustion generally does not perform compression ignition combustion but performs spark ignition combustion by driving the spark plug in a high-load operating range. [0003] Patent Document 2 describes a technique in which, like the engine of Patent Document 1, i...

AI Technical Summary

Problems solved by technology

In an engine that performs such compression ignition combustion, as the engine load increases, the compression ignition combustion becomes a combustion in which the pressure rises sharply, resulting in an increase in combustion noise.

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