Automotive engine control system
AssigneeMazda Motor Corporation
InventorsHiroshi Ninomiya, Tetsushi Hosokai
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Abstract
An engine control system computes an average value for an air-to-fuel feedback control based on which the amount of fuel vapors trapped in a canister, a purge air flow rate on the basis of a pressure difference between before and after a canister purge valve and a duty ratio at which the canister purge valve is activated, the amount of purged fuel vapors on the basis of the estimated trapped fuel vapor amount and purge air flow rate based on which the amount of fuel vapors entering into the combustion chamber. During execution of a canister purge, the purged gas flow rate is gradually varied toward a target rate so as to prevent the air-to-fuel feedback control from encountering disturbances.
Claims10
A control system for an engine equipped with an intake system and a canister purge system which forces purged gas containing fuel vapors from a canister to enter into the intake system in a specific range of engine operating conditions, said control system comprises:
- an air-to-fuel ratio detection sensor for detecting an air-to-fuel ratio of an air-fuel mixture;
- fuel injection control means for feedback controlling an amount of fuel injection to bring said air-to-fuel ratio to a target ratio in said specified range of engine operating conditions;
- and
- purge control means for gradually varying a purged gas flow rate, at which a canister purge is performed, at a changing rate so as to attain a target purged gas flow rate determined according to engine operating conditions after commencement of a canister purge, said changing rate being smaller in an engine operating range of small amounts of intake air than in an engine operating range of large amounts of intake air.
Dependencies are inferred from the claim text.