Internal-combustion engines – Charge forming device – Having fuel vapor recovery and storage system
Patent
1999-03-15
2000-09-19
Miller, Carl S.
Internal-combustion engines
Charge forming device
Having fuel vapor recovery and storage system
123198D, F02M 3302
Patent
active
061196630
ABSTRACT:
With a fuel vapor treatment unit where fuel vapor of an internal combustion engine which has been temporarily adsorbed into an adsorption device is drawn into an engine intake system under predetermined engine operating conditions, a judgment level is set based on a drive current of an electric pump for when air is pumped by the electric pump via a reference orifice having a reference aperture diameter, and the presence of fuel vapor leakage is diagnosed by comparing a drive current of the electric pump for when air is pumped by the electric pump bypassing the reference orifice and into piping to be leak diagnosed of the fuel vapor treatment unit, with the set judgment level. Moreover, the drive current of the electric pump for when air is pumped via the reference orifice is compared with a reference level, and when the drive current deviates from the reference level, the leakage diagnosis is stopped. Furthermore, refuelling judgment is performed, and the leakage diagnosis is started after judging that refuelling is completed. In this way, erroneous diagnosis due to blockage or contamination of the reference orifice, or erroneous diagnosis due to diagnosis being made during refuelling can be prevented, enabling an improvement in leakage diagnosis accuracy.
REFERENCES:
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patent: 5460141 (1995-10-01), Denz
patent: 5499614 (1996-03-01), Busato
patent: 5553577 (1996-09-01), Denz
patent: 5845625 (1998-12-01), Kidokoro
patent: 5881700 (1999-03-01), Gras
patent: 5967124 (1999-10-01), Cook
Miller Carl S.
Unisia Jecs Corporation
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