A ventilation control valve for a fuel tank is disposed in a ventilation passage which communicates an inside and an outside of a fuel tank. The ventilation control valve includes a float that floats on a liquid level of a fuel and moves up and down. The ventilation control valve includes a valve mechanism which switches a passage sectional area of the ventilation passage in conjunction with the float to an open state and a restricted state in which the passage sectional area is restricted from the opened state. The float has a volume chamber in which volume changes in accordance with a vertical movement of the float. A control gap as a flow rate adjusting mechanism is formed between the cylindrical wall of the float and the cylindrical wall of a case. Due to the control gap, the volume chamber functions as a damper.

A fuel tank unit includes a lid member configured to close an opening formed on a fuel tank. The fuel tank also includes an upper unit attached to the lid member and including a combination valve device configured to be introduced into the fuel tank via the opening formed on the fuel tank and configured to function as an evaporated fuel control valve and a full limit valve. The lid member includes a cylindrical protective case configured to protect the combination valve device of the upper unit when the combination valve device is introduced into the fuel tank via the opening. The protective case is configured to entirely enclose an outer circumferential surface of the combination valve device with a space therebetween.

An evaporated gas leak diagnosis method using an active purge pump is provided to detect a leak of the evaporated gas from a canister in a fuel system. The method includes diagnosing a failure of an active purge pump based on a signal generated by a pressure sensor installed on a vent line that extends from the canister to the atmosphere. The active purge pump is mounted on a purge line for connecting the canister with an intake pipe.

A fuel system comprising a fuel tank, a mixing volume configured to mix fuel vapor and air, the mixing volume comprising an outlet configured to be fluidly coupled to an engine, and a fuel vapor line configured to fluidly couple the fuel tank to the mixing volume.

A vent shut-off assembly configured to manage venting on a fuel tank includes a main housing, a poppet valve and an actuator. The main housing is positioned outside of the fuel tank and selectively vents to a canister. The poppet valve is disposed in the main housing and includes a plunger that provides over pressure relief (OPR) and over vacuum relief (OVR) functions. The actuator assembly can be housed in the main housing and includes a cam assembly having a cam shaft that includes a cam having a profile that one of opens and closes the poppet valve. When the poppet valve is in the closed position, vapor is precluded from passing between the fuel tank and the canister. When the poppet vale is in the open position, vapor is permitted from passing between the fuel tank and the canister.

A fuel tank isolation valve for a vehicle is provided. A valve opening operation or a valve closing operation is performed using guide protrusions configured to move along a guide slot, in response to an upward or downward movement of a plunger. The discharge of a battery is prevented. An abrupt change in the pressure of a fuel tank is prevented.

A fuel tank structure that makes it difficult for mud, water, dust or the like to enter a fuel tank and that can restrict a fuel leakage path when a vehicle falls. A fuel cap includes a cap body mounted to a fuel supply port of a fuel tank, and a pressure adjusting device provided in the cap body to adjust a pressure in the fuel tank. In the fuel cap, a space is formed as a hermetically closed space in which the pressure adjusting device is accommodated, and the space communicates with an exterior of the fuel tank via a breather tube.

A flow control valve includes a housing having a valve chamber, an inlet port, an outlet port, and a valve seat. In addition, the flow control valve includes a valve body disposed in the valve chamber, an actuator having an output rotational shaft, a feed screw mechanism to convert forward and reverse rotational motion of the output rotational shaft to axial reciprocating motion of the valve body, a backlash preventive spring positioned between the housing and the valve body, and a spring supporting device formed on the housing and having a spring seating surface. The spring seating surface is spaced from the valve seat in an opening direction of the valve body.

A fuel tank unit may include a fuel tank, a canister configured to adsorb and desorb vapor generated in the fuel tank, a vapor conduit communicating the fuel tank with the canister, and a full tank fuel level limiting valve device connected to a fuel tank-side end of the vapor conduit. The full tank fuel level limiting valve device includes a full tank fuel level limiting valve and an actuator. The full tank fuel level limiting valve includes a float that is configured to float due to a buoyancy force of fuel in the fuel tank so as to close the full tank fuel level limiting valve when the fuel tank is filled up. The actuator includes a valve closure prevention member that is configured to move and press the float when the actuator is activated, so as to prevent the float from moving in a valve closing direction.

The present invention discloses a method and operating liquid container system for controlling the internal pressure of an operating liquid container of a motor vehicle, wherein the method includes determining an internal pressure of the operating liquid container by means of a pressure sensor arranged in an operating liquid container interior; comparing the determined internal pressure with a predetermined maximum internal pressure by means of an electronic control device; outputting an opening signal from the control device to a vent valve that is arranged in a vent line or between the operating liquid container interior and the vent line, wherein the vent line fluidically connects the operating liquid container interior to the atmosphere when the determined internal pressure is equal to the maximum internal pressure or above the maximum internal pressure; and transferring the vent valve into an open position.