Patent ID: 6834535
Filing Date: 2004-12-28
Classification: F02M

Abstract:
A pressure-changing device for a leak check system to check for leaks in a 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; a pressure sensor that is disposed in a communicating path through which the pump communicates with the electro-magnetic valve and detects pressure in the communicating path; and a restrictor path that as a restrictor and branches from the communicating path, the restrictor path continuously communicating the communicating path with the absorbent vessel.