Title:
ABNORMAL CONDITION DIAGNOSTIC DEVICE FOR EVAPORATED GAS PURGE SYSTEM
Document Type and Number:
Japanese Patent JP3937258
Kind Code:
B
Abstract:
PROBLEM TO BE SOLVED: To prevent deterioration in drivability and to detect an abnormal condition in an early stage by finding evaporation gas concentration from a ratio between an air-fuel ratio feedback correction quantity deviation and a purge rate, comparing an evaporation gas concentration changing quantity and the evaporation gas concentration with determination values, and determining execution/stop of abnormal condition diagnosis.
SOLUTION: In abnormal condition diagnosis for an evaporation gas purge system 21, it is determined whether an evaporation gas generation quantity (an evaporation gas adsorption quantity inside a canister 23) is low or not by determining whether an evaporation gas concentration changing quantity, which is found on the basis of a ratio between an air-fuel ratio feedback correction quantity deviation and a final purge rate, and the evaporation gas concentration are below the predetermined values or not when an execution condition is established while a prohibition condition is not established. According to the current cooling water temperature and the like, a determination value is set from a map, and if NO is determined, that is, if the evaporation gas generation quantity is high, abnormal condition diagnosis is prohibited. If the evaporation gas generation quantity is low, a purge control valve 31 and a canister closing valve 26 are operated when the absolute value of atmospheric pressure variation is a predetermined value or less, and processes in four steps are carried out while performing determination of the processing steps and abnormal condition diagnosis is carried out.
Inventors:
Majima, Yoshihiro
Isomura, Shigenori
Isomura, Shigenori
Application Number:
JP1998000019298
Publication Date:
April 06, 2007
Filing Date:
January 30, 1998
Export Citation:
Assignee:
DENSO CORP
International Classes:
F02M25/08; G01M15/04; F02D41/02; F02D41/14; G01M15/00; F02M25/08; G01M15/04; F02D41/02; F02D41/14; G01M15/00; (IPC1-7): F02M25/08; F02M25/08; F02D41/02; F02D41/14; G01M15/00