Malfunction detection apparatus for detecting malfunction in evaporative fuel purge system
First Claim
1. A malfunction detection apparatus for detecting a malfunction in an evaporative fuel purge system having a fuel tank storing an amount of fuel, a vapor passage connecting said fuel tank and said canister, a purge passage through which said fuel vapor stored in the canister is purged into an intake passage of an engine, and a purge control valve provided in said purge passage to allow a purge operation by opening of the purge control valve, the malfunction detection apparatus comprising:
- a pressure introducing means for introducing a negative pressure from the intake passage of the engine into said evaporative fuel purge system;
a pressure detecting means for detecting a pressure inside said evaporative fuel purge system when the negative pressure is introduced into the system by said pressure introducing means;
an air-fuel ratio fluctuation suppressing means for suppressing a fluctuation of the air-fuel ratio of mixture gas suctioned into the engine which results from suctioning of the fuel vapor collected in the fuel tank, the suppression being effected by controlling said pressure introducing means when the negative pressure is introduced into said evaporative fuel purge system by said pressure introducing means;
a determining means for determining the existence of a malfunction in said evaporative fuel purge system by monitoring a pressure in said evaporative fuel purge system, said monitoring using values supplied by said pressure detecting means.
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Accused Products
Abstract
A malfunction detection apparatus for detecting a malfunction in an evaporative fuel purge system, which malfunction detection apparatus is able to suppress a fluctuation of an air-fuel ratio. A negative pressure inside an intake passage is introduced into the evaporative fuel purge system. The existence/nonexistence of a malfunction in the evaporative fuel purge system is determined by using pressure values inside the evaporative fuel purge system which values are detected and supplied by a pressure detecting unit. The apparatus is provided with an air-fuel ratio fluctuation suppressing unit for suppressing a fluctuation of the air-fuel ratio of air suctioned into an engine when introducing the negative pressure into the evaporative fuel purge system.
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Citations
18 Claims
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1. A malfunction detection apparatus for detecting a malfunction in an evaporative fuel purge system having a fuel tank storing an amount of fuel, a vapor passage connecting said fuel tank and said canister, a purge passage through which said fuel vapor stored in the canister is purged into an intake passage of an engine, and a purge control valve provided in said purge passage to allow a purge operation by opening of the purge control valve, the malfunction detection apparatus comprising:
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a pressure introducing means for introducing a negative pressure from the intake passage of the engine into said evaporative fuel purge system; a pressure detecting means for detecting a pressure inside said evaporative fuel purge system when the negative pressure is introduced into the system by said pressure introducing means; an air-fuel ratio fluctuation suppressing means for suppressing a fluctuation of the air-fuel ratio of mixture gas suctioned into the engine which results from suctioning of the fuel vapor collected in the fuel tank, the suppression being effected by controlling said pressure introducing means when the negative pressure is introduced into said evaporative fuel purge system by said pressure introducing means; a determining means for determining the existence of a malfunction in said evaporative fuel purge system by monitoring a pressure in said evaporative fuel purge system, said monitoring using values supplied by said pressure detecting means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification