Leak check for fuel vapor purge system
First Claim
Patent Images
1. An apparatus of checking a leak in a fuel vapor purge system comprising:
- pressure detecting means for detecting a pressure of a fuel vapor purge system including a fuel tank;
leak checking means for checking presence or absence of the leak in the fuel vapor purge system based on the pressure of the fuel vapor purge system detected by the pressure checking means when the fuel vapor purge system is maintained in a hermetically closed state;
erroneous check avoiding means for avoiding an erroneous check caused by a deformation of the fuel tank;
restricting means for restricting the pressure of the fuel vapor purge system into a predetermined restricted value when the leak checking means checks the leak;
temperature determining means for determining a temperature in the fuel tank or a temperature around the fuel tank or information related thereto; and
means for changing the restricted value based on the temperature determined by the temperature determining means.
1 Assignment
0 Petitions
Accused Products
Abstract
A leak check system executes a leak check processing. In the leak check processing, the system closes a canister valve and a purge valve to close the fuel vapor purge system. Then, the system detects and monitors a pressure in the fuel vapor purge system. During the leak check processing, the system detects a rapid change of the pressure that is caused by a deformation of a wall of a fuel tank. The system cancels or suspends the processing to avoid erroneous detection of the leak. If the leak check is canceled, the system opens the canister valve to open the fuel vapor purge system.
-
Citations
30 Claims
-
1. An apparatus of checking a leak in a fuel vapor purge system comprising:
-
pressure detecting means for detecting a pressure of a fuel vapor purge system including a fuel tank;
leak checking means for checking presence or absence of the leak in the fuel vapor purge system based on the pressure of the fuel vapor purge system detected by the pressure checking means when the fuel vapor purge system is maintained in a hermetically closed state;
erroneous check avoiding means for avoiding an erroneous check caused by a deformation of the fuel tank;
restricting means for restricting the pressure of the fuel vapor purge system into a predetermined restricted value when the leak checking means checks the leak;
temperature determining means for determining a temperature in the fuel tank or a temperature around the fuel tank or information related thereto; and
means for changing the restricted value based on the temperature determined by the temperature determining means. - View Dependent Claims (2)
-
-
3. An apparatus of checking a leak in a fuel vapor purge system comprising:
-
pressure detecting means for detecting a pressure of a fuel vapor purge system including a fuel tank;
leak checking means for checking presence or absence of the leak in the fuel vapor purge system based on the pressure of the fuel vapor purge system detected by the pressure checking means when the fuel vapor purge system is maintained in a hermetically closed state;
erroneous check avoiding means for avoiding an erroneous check caused by a deformation of the fuel tank;
restricting means for restricting the pressure of the fuel vapor purge system into a predetermined restricted value when the leak checking means checks the leak; and
means for correcting the restricted value in a direction of approaching an atmospheric pressure when the pressure of the fuel vapor purge system detected by the pressure detecting means is rapidly changed in checking the leak by the leak checking means. - View Dependent Claims (4)
-
-
5. An apparatus of checking a leak of a fuel vapor purge system which is a fuel vapor purge system for purging fuel vapor generated by evaporating a fuel in a fuel tank to an intake system of an engine, said apparatus comprising:
-
pressure detecting means for detecting a pressure of the fuel vapor purge system including the fuel tank;
a first valve for opening and closing an atmosphere communicating path of the fuel vapor purge system;
leak checking means for checking presence or absence of a leak of the fuel vapor purge system based on the pressure detected by the pressure detecting means when at least the first valve is closed to thereby maintain the fuel vapor purge system in a hermetically closed state in stopping to operate the engine; and
valve controlling means for temporarily releasing the hermetically closed state of the fuel vapor purge system by temporarily opening the first valve after finishing to check the leak and thereafter closing the first valve again. - View Dependent Claims (6, 7)
-
-
8. A method of checking a leak in a fuel vapor purge system, the method comprising:
-
detecting a pressure of a fuel vapor purge system including a fuel tank;
checking presence or absence of a leak in the fuel vapor purge system based on the detected pressure of the fuel vapor purge system when the fuel vapor purge system is maintained in a hermetically closed state;
avoiding an erroneous check caused by a deformation of the fuel tank;
restricting the pressure of the fuel vapor purge system into a predetermined restricted value when the leak is checked;
determining a temperature in the fuel tank or a temperature around the fuel tank; and
changing the restricted value based on the determined temperature. - View Dependent Claims (9)
-
-
10. A method of checking a leak in a fuel vapor purge system, the method comprising:
-
detecting a pressure of a fuel vapor purge system including a fuel tank;
checking presence or absence of a leak in the fuel vapor purge system based on the detected pressure of the fuel vapor purge system when the fuel vapor purge system is maintained in a hermetically closed state;
avoiding an erroneous check caused by a deformation of the fuel tank;
restricting the pressure of the fuel vapor purge system into a predetermined restricted value when the leak is checked; and
corrected the restricted value in a direction of approaching an atmospheric pressure when the detected pressure is rapidly changed in the checking of the leak. - View Dependent Claims (11)
-
-
12. A method of checking a leak of a fuel vapor purge system which is a fuel vapor purge system for purging fuel vapor generated by evaporating a fuel in a fuel tank to an intake system of an engine, said method comprising:
-
detecting a pressure of the fuel vapor purge system including the fuel tank;
opening and closing an atmosphere communicating path of the fuel vapor purge system via a first valve;
checking presence or absence of a leak of the fuel vapor purge system based on the detected pressure when at least the first valve is closed to thereby maintain the fuel vapor purge system in a hermetically closed state in stopping to operate the engine; and
temporarily releasing the hermetically closed state of the fuel vapor purge system by temporarily opening the first valve after finishing to check the leak and thereafter closing the first valve again. - View Dependent Claims (13, 14)
-
-
15. An apparatus of checking a leak in a fuel vapor purge system for an internal combustion engine comprising:
-
a first valve for opening and closing an atmosphere communicating path of the fuel vapor purge system;
leak checking means for checking the presence or absence of a leak in the fuel vapor purge system based on a pressure in the fuel vapor purge system when the fuel vapor purge system is in a hermetically closed state with the first valve closed while the engine is stopped; and
valve control means for temporarily releasing the hermetically closed state of the fuel vapor purge system by temporarily opening the first valve after finishing checking the leak and thereafter closing the first valve again. - View Dependent Claims (16, 17, 18)
-
-
19. A method of checking a leak in a fuel vapor purge system for an internal combustion engine, the method comprising:
-
stopping the internal combustion engine;
hermetically closing the fuel vapor purge system by closing a first valve that opens and closes an atmosphere communicating path of the fuel vapor purge system;
checking the presence or absence of a leak in the fuel vapor purge system based on a pressure in the fuel vapor purge system;
temporarily opening the first valve after finishing checking the leak; and
closing the first valve again. - View Dependent Claims (20, 21, 22)
-
-
23. An apparatus of checking a leak in a fuel vapor purge system for an internal combustion engine comprising:
-
a first valve for opening and closing an atmosphere communicating path of the fuel vapor purge system; and
leak checking means for checking the presence or absence of a leak in the fuel vapor purge system based on a pressure in the fuel vapor purge system when the fuel vapor purge system is in a hermetically closed state with the first valve closed while the engine is stopped;
wherein the leak checking means checks a leak when a condition that fuel vapor is liable to generate at a time when the engine is stopped is satisfied. - View Dependent Claims (24, 25, 26)
-
-
27. A method of checking a leak in a fuel vapor purge system for an internal combustion engine, the method comprising:
-
stopping the internal combustion engine;
hermetically closing the fuel vapor purge system by closing a first valve that opens and closes an atmosphere communicating path of the fuel vapor purge system; and
checking the presence or absence of a leak in the fuel vapor purge system based on a pressure in the fuel vapor purge system;
wherein the leak is checked when a condition that fuel vapor is liable to generate at a time when the engine is stopped is satisfied. - View Dependent Claims (28, 29, 30)
-
Specification