Internal combustion engine and control method for same

摘要

An engine exhaust gas post-treatment device including a mechanism that can vary opening timing of an exhaust valve, and a control method. A unit is configured to raise a temperature of a part or all of the device to not less than a preset temperature by the mechanism opening the exhaust valve in an exhaust stroke at normal combustion within a range of an afterburning period, and the mechanism feeds the device an exhaust gas whose temperature and pressure are high due to combustion of fuel injected into a cylinder. After the exhaust gas is treated by the device, or when the device is regenerated, the unit adds an unburned fuel component to the exhaust gas by an additional injection of an injector in the cylinder or an injection of a hydrocarbon addition nozzle provided at an exhaust port in accordance with the valve opening timing by the unit.

主权项

1. An internal combustion engine, comprising:
a cylinder; a fuel injection valve which injects a main injection of fuel into the cylinder; an exhaust passage through which an exhaust gas from the cylinder passes; a post-treatment device in the exhaust passage to treat the exhaust gas; a variable valve mechanism that changes a timing of an opening of an exhaust valve of the cylinder; a sensor which detects a temperature of the post-treatment device; and a controller which is connected to the sensor and is configured to—
control the fuel injection valve and the variable valve mechanism when the exhaust gas is treated by the post-treatment device, or when the post-treatment device is regenerated,control, by the variable valve mechanism, the exhaust valve to, when the temperature of the post-treatment device is below a preset catalyst activation temperature, open the exhaust valve in a range of an afterburning period set at the initial stage of an expansion stroke and close the exhaust valve before a bottom dead center of the expansion stroke, before opening and closing at an exhaust stroke, andcontrol, when the temperature of part or all of the post-treatment device is raised to not less than the catalyst activation temperature, the fuel injection valve to perform an after injection between opening of the exhaust valve within the range of the afterburning period and closing the exhaust valve before the bottom dead center of the expansion stroke.