Exhaust valve control method and exhaust valve control device for diesel engine
AssigneeIsuzu Motors Limited
InventorJunichiro Nitta
Life of this patent
Estimating the term…
Abstract
An exhaust valve control method for a diesel engine 6 for switching between a normal combustion mode and a premixed combustion mode according to operating conditions; an exhaust valve 9 is opened only in the exhaust stroke in the normal combustion mode, and two-stage valve opening control is carried out to open the exhaust valve 9 not only in the exhaust stroke, but also between the latter part of the air inlet stroke and the initial stage of the compression stroke in the premixed combustion mode.
Claims8
An exhaust valve control method for a diesel engine for switching between a normal combustion mode and a premixed combustion mode according to operating conditions,
- wherein during the normal combustion mode, an exhaust valve is opened only in an exhaust stroke, and during the premixed combustion mode, the exhaust valve is opened not only in the exhaust stroke but also after the opening of an air inlet valve in an air inlet stroke and before a compression stroke;
- wherein said exhaust valve is opened during the air inlet stroke when an A /F value is more than a predetermined value and a knocking intensity is not greater than a different predetermined value;
- and
- wherein said exhaust valve is closed during the compression stroke when an exhaust pipe internal pressure is greater than or equal to a cylinder internal pressure.
An exhaust valve control device for a diesel engine for switching between a normal combustion mode and a premixed combustion mode according to operating conditions, comprising:
- an exhaust valve drive device capable of changing an opening and closing timing of an exhaust valve;
- and
- a control unit for controlling said exhaust valve drive device,
- wherein said control unit controls said exhaust valve drive device so as to open said exhaust valve only in an exhaust stroke during said normal combustion mode,
- wherein said control unit controls said exhaust valve drive device so as to open said exhaust valve not only in the exhaust stroke, but also after the opening of an air inlet valve in an air inlet stroke and before a compression stroke during said premixed combustion mode,
- wherein the exhaust valve control device further comprises an MAF sensor for measuring an air inlet rate, a knocking sensor for measuring the intensity of knocking, injection quantity detection means for detecting a fuel injection quantity, an exhaust pipe internal pressure sensor for measuring an exhaust pipe internal pressure, and cylinder internal pressure detection means for detecting a cylinder internal pressure,
- wherein said control unit determines a valve opening timing of said exhaust valve in the air inlet stroke based on conditions that an A /F value calculated from the air inlet rate measured by said MAF sensor and the fuel injection quantity detected by said fuel injection quantity detection means is more than a predetermined value and the knocking intensity measured by said knocking sensor is not greater than a different predetermined value, and
- wherein said control unit determines a valve closing timing of said exhaust value in the compression stroke based on condition that the exhaust pipe internal pressure measured by said exhaust pipe internal pressure sensor is higher than the cylinder internal pressure detected by said cylinder internal pressure detection means.
Dependencies are inferred from the claim text.