Patent ID: 6167873
Filing Date: 2001-01-02
Classification: F02D,F02M,Y02T

Abstract:
An apparatus controlling an EGR valve of a diesel engine, said EGR valve being provided in an EGR passage that recirculats a part of an exhaust gas in an exhaust passage of said diesel engine so as to return said a part of said exhaust gas to an inlet passage thereof and including a valve body, a valve seat, and a step motor that fully closes said EGR passage by moving said valve body so as to abut onto said valve seat and that opens said EGR passage by moving said valve body away from said valve seat, said valve body being located on a side of said exhaust passage as viewed from said valve seat, said apparatus comprising: a battery voltage determining section determining whether a voltage of a battery connected to said step motor is not higher than a predetermined voltage; a water temperature determining section determining whether a temperature of a cooling water of said diesel engine is not lower than a predetermined temperature; an exhaust gas pressure determining section determining whether an exhaust gas pressure of said diesel engine is in a state corresponding to a predetermined pressure or a pressure higher than said predetermined pressure; and a forcedly fully closing section forcedly fully closing said EGR valve when it is determined in said battery voltage determining section that said voltage of said battery is not higher than said predetermined voltage, and/or it is determined in said water temperature determining section that said temperature of said cooling water of said diesel engine is not lower than said predetermined temperature, and it is determined in said exhaust gas pressure determining section that said exhaust gas pressure of said diesel engine is in said state corresponding to said predetermined pressure or said pressure higher than said predetermined pressure.