Spark-ignition direct injection engine

摘要

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.

主权项

1. A spark-ignition direct injection engine, comprising:
an engine body having a cylinder; a fuel injection valve for injecting fuel into the cylinder; a fuel pressure setting mechanism for setting a pressure of the fuel to be injected by the fuel injection valve; an ignition plug arranged to be oriented toward an inside of the cylinder and for igniting mixture gas within the cylinder; and a controller for operating the engine body by controlling at least the fuel injection valve, the fuel pressure setting mechanism, and the ignition plug, wherein when an operating state of the engine body is within a first range that is a predetermined low engine load range, the controller operates the engine body to perform compression-ignition combustion where the mixture gas within the cylinder is compressed to ignite, wherein when the operating state of the engine body is within a second range where the engine load is higher than the first range where the compression-ignition combustion is performed, the controller controls the ignition plug at a predetermined timing so as to operate the engine body to perform spark-ignition combustion, wherein when the operating state of the engine body is within a specific high engine load part of the first range including a boundary between the first and second ranges, the controller sets the fuel pressure to be a high fuel pressure of 30 MPa or above by the fuel pressure setting mechanism, and the controller retards the compression ignition to after a compression top dead center by controlling the fuel injection valve to perform the fuel injection into the cylinder at least in a period from a late stage of compression stroke to an early stage of expansion stroke, and wherein when the operating state of the engine body is within a part of the first range where the engine load is below the specific part, the controller controls the fuel injection valve to perform the fuel injection into the cylinder at least in a period from intake stroke to a middle stage of the compression stroke.