Self-diagnosable fuel-purging system used for fuel processing system
First Claim
1. A diagnosing system for a fuel-purging system used for a fuel processing system, said fuel purging system causing a fuel to be introduced from a fuel tank into a canister packed with an absorbent for absorbing the fuel thereon, and causing the fuel absorbed onto the absorbent to be introduced into an engine, said diagnosing system comprising:
- first detecting means for detecting a fuel purging condition in which the fuel absorbed onto the absorbent of the canister is supplied to the engine, to produce a first signal representative of the fuel purging condition;
second detecting means for monitoring an air/fuel ratio in an exhaust gas from the engine to produce a second signal representative of the air/fuel ratio;
third detecting means for monitoring temperature in the canister to produce a third signal representative of the temperature in the canister; and
discriminating means for determining abnormality of the fuel-purging system on the basis of the second and third signal values when the fuel-purging condition is detected.
1 Assignment
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Accused Products
Abstract
A self-diagnosable fuel-purging system used for a fuel processing system causes a fuel to be introduced into a canister packed with an adsorbent, such as activated carbon, onto which the introduced fuel is adsorbed, and causes the adsorbed fuel to be introduced into an engine when a negative pressure greater than a predetermined value is produced in an intake manifold upstream of a throttle valve. The fuel-purging system includes discriminating means for determining whether or not the fuel-purging system itself is normal on the basis of output signals representative of an air/fuel ratio in an exhaust gas from the engine and a temperature in the canister. The discriminating means determines abnormality of the fuel-purging system when both of the temperature in the canister and the air/fuel ratio are substantially constant while a fuel-purging condition, in which the fuel adsorbed onto the adsorbent in the canister is supplied to the engine, is detected.
20 Citations
10 Claims
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1. A diagnosing system for a fuel-purging system used for a fuel processing system, said fuel purging system causing a fuel to be introduced from a fuel tank into a canister packed with an absorbent for absorbing the fuel thereon, and causing the fuel absorbed onto the absorbent to be introduced into an engine, said diagnosing system comprising:
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first detecting means for detecting a fuel purging condition in which the fuel absorbed onto the absorbent of the canister is supplied to the engine, to produce a first signal representative of the fuel purging condition; second detecting means for monitoring an air/fuel ratio in an exhaust gas from the engine to produce a second signal representative of the air/fuel ratio; third detecting means for monitoring temperature in the canister to produce a third signal representative of the temperature in the canister; and discriminating means for determining abnormality of the fuel-purging system on the basis of the second and third signal values when the fuel-purging condition is detected. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A fuel-purging system used for a fuel processing system for processing a fuel introduced into an engine, said fuel-purging system comprising:
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a canister which communicates with a fuel tank, and into which a fuel is introduced from the fuel tank, said canister being packed with an absorbent for absorbing the fuel thereon; a first fluid passage for establishing a first fluid communication between the canister and an intake manifold downstream of a throttle valve; a second fluid passage for establishing a second fluid communication between the canister and the intake manifold upstream of the throttle valve; a first valve for being selectively open and closed to establish and block the first and second fluid communications; first detecting means for detecting a fuel purging condition in which the fuel absorbed onto the absorbent of the canister is supplied to the engine, to produce a first signal representative of the fuel purging condition; second detecting means for monitoring an air/fuel ratio in an exhaust gas from the engine to produce a second signal representative of the air/fuel ratio; third detecting means for monitoring temperature in the canister to produce a third signal representative of the temperature in the canister; and discriminating means for determining abnormality of the fuel-purging system on the basis of said second and third signal values when the fuel purging condition is detected by means of the first detecting means. - View Dependent Claims (8, 9, 10)
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Specification