Spark-ignition direct injection engine

Abstract

A spark-ignition direct injection engine is provided. The engine includes an engine body, a fuel injection valve, a fuel pressure setting mechanism, an ignition plug, and a controller. The controller operates the engine to perform compression-ignition combustion within a first operating range, and controls the ignition plug to operate the engine to perform spark-ignition combustion within a second operating range. Within a specific part of the first range, the controller sets the fuel pressure to 30 MPa or above, and retards the compression ignition to after a compression top dead center by controlling the injection valve to inject fuel into a cylinder in a period from a late stage of compression stroke to an early stage of expansion stroke. Below the specific part, the controller controls the fuel injection valve to inject the fuel into the cylinder in a period 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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