Fuel vapor treatment system
First Claim
1. A pressure-changing device for a leak check system to check leak in the fuel vapor treatment system, which adsorbs fuel vapor forming in a fuel tank by adsorbent in an adsorption vessel and discharges the adsorbed fuel vapor into a suction pipe, by changing pressure in a fuel vapor path through which fuel vapor passes in the fuel vapor treatment system, the pressure-changing device comprising:
- a pump that changes pressure in the fuel vapor path;
an electromagnetic valve that is disposed between the fuel vapor path and the pump and provides a communication between the fuel vapor path and the pump and a communication between the fuel vapor path and the atmosphere; and
a pressure sensor that is disposed in a communicating path through which the pump communicates with the electromagnetic valve and detects pressure in the communicating path.
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Accused Products
Abstract
A pressure-changing device of a leak check system for a fuel vapor treatment system has a pressure chamber formed in a peripheral space of a communicating path connecting a pump with an electromagnetic valve, the pressure chamber being deviated from flow delivered by the pump. The electromagnetic valve is opened to connect the communicating path with a canister. Then, a purge valve is closed and the pump is turned on to change pressure in a fuel vapor path. A pressure sensor attached on a side wall of the pressure chamber detects pressure in the communicating path to determine pressure in the fuel vapor path. The leak check system judges existence of leak in the fuel vapor treatment system from pressure in the fuel vapor path.
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Citations
12 Claims
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1. A pressure-changing device for a leak check system to check leak in the fuel vapor treatment system, which adsorbs fuel vapor forming in a fuel tank by adsorbent in an adsorption vessel and discharges the adsorbed fuel vapor into a suction pipe, by changing pressure in a fuel vapor path through which fuel vapor passes in the fuel vapor treatment system, the pressure-changing device comprising:
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a pump that changes pressure in the fuel vapor path;
an electromagnetic valve that is disposed between the fuel vapor path and the pump and provides a communication between the fuel vapor path and the pump and a communication between the fuel vapor path and the atmosphere; and
a pressure sensor that is disposed in a communicating path through which the pump communicates with the electromagnetic valve and detects pressure in the communicating path. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification