Diagnosis apparatus and method for an exhaust gas recirculation unit of an internal combustion engine
AssigneeUnisia Jecs Corporation
InventorsKenichi Machida, Hirokazu Shimizu
Life of this patent
Estimating the term…
Abstract
A exhaust gas recirculation control value is forcibly open/close controlled at the time of steady operation. An estimation of whether or not the actual exhaust gas recirculation quantity has changed with open/close control of the exhaust gas recirculation control valve, is then made based on whether or not a change in combustion pressure accompanying the open/close is a value estimated for the operating conditions.
Claims16
A diagnosis apparatus for an exhaust gas recirculation unit of an internal combustion engine wherein a portion of the engine exhaust gas is recirculated to the engine intake system via an exhaust gas recirculation passage in which is disposed an exhaust gas recirculation control valve, said apparatus comprising:
- combustion pressure detecting means for detecting combustion pressure of the engine, difference computing means for computing a difference between a combustion pressure of the engine detected under an open control condition of said exhaust gas recirculation control valve, and a combustion pressure of the engine detected under a close control condition of said exhaust gas recirculation control valve,
- difference estimating means for establishing an estimation value for sad difference in accordance with operating conditions, and
- diagnosis means for judging the presence or absence of an abnormality in said exhaust gas recirculation unit based on said difference computed by said difference computing means and said estimation value established by said difference estimating means.
A diagnosis method for an exhaust gas recirculation unit of an internal combustion engine wherein a portion of the engine exhaust gas is recirculated to the engine intake system via an exhaust gas recirculation passage in which is disposed an exhaust gas recirculation control valve, said method including steps of;
- computing a difference between a combustion pressure of the engine detected under open control conditions of said exhaust gas recirculation control valve, and combustion pressure of the engine detected under close control conditions of said exhaust gas recirculation control valve, establishing an estimation value for said difference in accordance with operating conditions, and comparing the computed actual combustion pressure difference with said estimation value, to thereby judge the presence or absence of an abnormality in said exhaust gas recirculation unit.
Dependencies are inferred from the claim text.