Abstract: A system 10 for controlling the operation of a propane powered vehicle engine includes a gas sensor 28 for providing a fuel rich signal and a fuel lean signal to a controller 20. The controller is also responsive to a tachometer 26 which senses the engine rpm. When the engine speed is in excess of a preselected value and is not decelerating, the controller generates an unacceptable engine operation signal if the period of duration of the fuel rich signal exceeds a preselected value. A warning unit 32 is provided for alerting the operator of a service required signal from the controller. A fuel shutoff device 30 automatically terminates the fuel supply to the engine in response to a fuel shutoff signal from the controller. The method of the invention allows for vehicle startup after the fuel shutoff device has been activated. The invention is particularly well suited for requiring a propane powered vehicle engine to output an acceptable level of carbon monoxide in the exhaust gas.

Abstract: A system for vaporizing liquefied gas fuel supplied from a fuel tank and supplying it to an internal combustion engine includes a release path for releasing spontaneously evaporated fuel gas in said tank out of the tank. A catalytic burner is disposed in the release path for decomposing the fuel gas into hot steam and carbon dioxide. A release control valve disposed between the catalytic burner and the fuel tank selectively causes the burner and the fuel tank to communicate and to be decoupled from each other.

Abstract: A system for regulating fuel flow in a fuel line from a supply of fuel to an engine, comprising: a fuel regulator disposed in the fuel line intermediate of the engine and the fuel supply regulating the flow of fuel to the engine; vacuum lockoff apparatus, disposed in the fuel line intermediate of the fuel regulator and the fuel supply and connected to the engine by an air passageway, sensing a partial vacuum condition at the engine, the vacuum lockoff means allowing flow of fuel in the fuel line when a partial vacuum condition is sensed and prohibiting flow of fuel in the fuel line when the partial vacuum condition is no longer sensed; one way check valve, disposed intermediate of the engine and the vacuum lockoff means in the air passageway, maintaining partial vacuum condition at the vacuum lockoff means; and bypass valve means, connected to the air passageway so as to provide an air passageway bypassing the one way check valve, for allowing restricted flow of air to the vacuum lockoff apparatus whereby the

Abstract: The present invention relates to a system for shutting off the LPG fuel supply route in a vehicle except in case of necessity. Namely, when an engine is stopped and a starting switch is in switched off, a solenoid valve is operated to shut off the LPG fuel supply route to prevent the LPG fuel from leaking out to the carburetor and to keep the vehicle from suddenly lurching out.

Abstract: A combustion engine includes an inlet duct including a control valve. A vaporizer-pressure regulator for use with the combustion engine has a first space divided into two parts by a diaphragm contained in the space, the diaphragm actuating a first shut-off valve co-operating with a gas supply orifice of the first space, while the part of the space in which the gas supply orifice opens out is connected through a connecting duct with a second space comprising a member affecting the gas pressure, the space communicating with the inlet duct of the combustion engine, whereby that part of the first space which is located on the side of the diaphragm actuating the first shut-off valve remote from the first shut-off valve is connected both downstream and upstream of the control valve with the inlet duct of the combustion engine through a pressure duct network including means acting upon the size of the passage of the ducts in dependence on the load of the combustion engine occurring during operation.