Abnormality diagnostic system for evaporative fuel-processing system of internal combustion engine for vehicles
First Claim
1. In an abnormality diagnostic system for an evaporative fuel-processing system for an internal combustion engine installed in a vehicle and having an intake system, and a fuel tank, the system comprising an evaporative emission-control system including a canister having an air inlet port provided therein, an evaporative fuel-guiding passage extending between said fuel tank and said canister, a purging passage extending between said canister and said intake system of said engine, and a first control valve arranged across said purging passage,the improvement comprising:
- pressure detecting means for detecting pressure within said evaporative emission control system;
negatively pressurizing means for bringing said evaporative emission control system into a predetermined negatively pressurized state;
external diagnostic means provided externally of said engine, said external diagnostic means being humanly operable for diagnosing operating conditions of said engine, said external diagnostic means for generating a command signal for carrying out an abnormality diagnosis of said evaporative emission control system when said engine is in a predetermined operating condition suitable for said abnormality diagnosis of said evaporative emission control system; and
abnormality determining means responsive to said command signal from said external diagnostic means, for determining whether there is an abnormality in said evaporative emission control system based upon an output from said pressure detecting means, which output is obtained when said evaporative emission control system has been brought into said predetermined negatively pressurized state, when said engine is in said predetermined operation condition.
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Abstract
An evaporative fuel-processing system for an internal combustion engine, comprises an evaporative emission control system in which a first control valve is arranged across an evaporative fuel-guiding passage extending between a fuel tank and a canister, a second control valve across a purging passage extending between the canister and the intake system of the engine, and a third control valve at an air inlet port of the canister, respectively. An external diagnostic device is humanly operatable for diagnosing operating conditions of the engine and the vehicle. An ECU is responsive to an output from an external diagnostic device which diagnoses operating conditions of the engine, for determining whether there is an abnormality in the evaporative emission control system, based upon an output from the tank internal pressure sensor, which is obtained when the evaporative emission control system has been brought into the predetermined negatively pressurized state, when the engine is in a predetermined operating condition.
29 Citations
11 Claims
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1. In an abnormality diagnostic system for an evaporative fuel-processing system for an internal combustion engine installed in a vehicle and having an intake system, and a fuel tank, the system comprising an evaporative emission-control system including a canister having an air inlet port provided therein, an evaporative fuel-guiding passage extending between said fuel tank and said canister, a purging passage extending between said canister and said intake system of said engine, and a first control valve arranged across said purging passage,
the improvement comprising: -
pressure detecting means for detecting pressure within said evaporative emission control system; negatively pressurizing means for bringing said evaporative emission control system into a predetermined negatively pressurized state; external diagnostic means provided externally of said engine, said external diagnostic means being humanly operable for diagnosing operating conditions of said engine, said external diagnostic means for generating a command signal for carrying out an abnormality diagnosis of said evaporative emission control system when said engine is in a predetermined operating condition suitable for said abnormality diagnosis of said evaporative emission control system; and abnormality determining means responsive to said command signal from said external diagnostic means, for determining whether there is an abnormality in said evaporative emission control system based upon an output from said pressure detecting means, which output is obtained when said evaporative emission control system has been brought into said predetermined negatively pressurized state, when said engine is in said predetermined operation condition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. In an abnormality diagnostic system for an evaporative fuel-processing system for an internal combustion engine installed in a vehicle and having an intake system, and a fuel tank, the system comprising an evaporative emission-control system including a canister having an air inlet port provided therein, an evaporative fuel-guiding passage extending between said fuel tank and said canister, a purging passage extending between said canister and said intake system of said engine, and a first control valve arranged across said purging passage,
the improvement comprising: -
pressure detecting means for detecting pressure within said evaporative emission control system; negatively pressurizing means for bringing said evaporative emission control system into a predetermined negatively pressurized state; external diagnostic means provided externally of said vehicle, said external diagnostic means being humanly operable for diagnosing operating conditions of said engine, said external diagnostic means for generating a command signal for carrying out an abnormality diagnosis of said evaporative emission control system when said engine is in a predetermined operating condition suitable for said abnormality diagnosis of said evaporative emission control system; and abnormality determining means responsive to said command signal from said external diagnostic means, for determining whether there is an abnormality in said evaporative emission control system based upon an output from said pressure detecting means, which output is obtained when said evaporative emission control system has been brought into said predetermined negatively pressurized state, when said engine is in said predetermined operation condition. - View Dependent Claims (11)
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Specification