Fuel vapor treatment system
AssigneesDenso Corporation, Nippon Soken, Inc.
InventorsShinsuke Takakura, Masao Kano, Noriyasu Amano
Life of this patent
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Abstract
An ECU computes a transit time from a time when the fuel vapor passes the purge valve right after the purge valve is opened until a time when the fuel vapor reaches a vicinity of the fuel injector. Further more, the ECU computes a fuel vapor concentration at the vicinity of the fuel injector after the transit time has elapsed based on a first-order lag curve which is defined by a maximum variation of the fuel vapor concentration and a time constant. Correcting the fuel injection quantity according to the fuel vapor concentration at the vicinity of the injector restricts a disturbance of air-fuel ratio at a time of starting purge process.
Claims10
A fuel vapor treatment system mounted on an internal combustion engine which has a fuel injector for injecting fuel into an intake pipe, comprising:
- a canister containing an adsorbent which temporarily adsorbs fuel vapor generated in a fuel tank;
- a purge passage which introduces fuel vapor desorbed from the canister into the intake pipe;
- a purge valve which opens/closes the purge passage;
- a transit time computing means for computing a first transit time from a time when the fuel vapor passes the purge valve right after the purge valve is opened until a time when the fuel vapor reaches a vicinity of the fuel injector;
- and
- a concentration computing means for computing a fuel vapor concentration at the vicinity of the fuel injector after the first transit time has elapsed based on a first-order lag curve which is defined by a maximum variation of the fuel vapor concentration and a time constant.
A fuel vapor treatment system mounted on an internal combustion engine which has a fuel injector for injecting fuel into an intake pipe, comprising:
- a canister containing an adsorbent which temporarily adsorbs fuel vapor generated in a fuel tank;
- a purge passage which introduces fuel vapor desorbed from the canister into the intake pipe;
- a purge valve which opens/closes the purge passage;
- a transit time computing means for computing a second transit time from a time when the fuel vapor passes the purge valve right before the purge valve is closed until a time when the fuel vapor reaches a vicinity of the fuel injector;
- and
- a concentration computing means for computing a fuel vapor concentration at the vicinity of the fuel injector after the second transit time has elapsed based on a first-order lag curve which is defined by a maximum variation of the fuel vapor concentration and a time constant.
Dependencies are inferred from the claim text.