Abstract: A method of providing fugitive gases to an engine air supply. An air filter is positioned on the engine intake of said engine. The air filter creates a negative pressure in the engine intake downstream of the air filter. A source of fugitive gases pass to the engine intake and are collected by the negative pressure downstream of the air filter.

Abstract: A control system for a turbo charged natural gas engine. A butterfly valve used for fuel control upstream of a carburetor provides non-linear flow response during opening and closing and a flow compensator compensates for the non-linear response. A throttle valve position sensor acts in association with a controller which compares the throttle valve position signal with a predetermined set point and thereby opens or closes the waste gate of the turbo charger which affects oxygen content in the exhaust. A compensator for a throttle valve used with electronic engine controllers is also provided.

Abstract: Apparatus and method for collecting fugitive combustible gases and adding the gases as a supplementary fuel source to an engine. The fugitive combustible gases are added to the air inletted to the air supply and a control is provided to allow adjustment of the normal fuel supplied to the engine following the addition of the fugitive combustible gases. The fugitive combustible gases provide an energy source for the engine and the combustion of the gases reduces the greenhouse effect if the gases contain methane.

Abstract: A control system for a turbo charged natural gas engine. A butterfly valve used for fuel control upstream of a carburetor provides non-linear flow response during opening and closing and a flow compensator compensates for the non-linear response. A throttle valve position sensor acts in association with a controller which compares the throttle valve position signal with a predetermined set point and thereby opens or closes the waste gate of the turbo charger which affects oxygen content in the exhaust. A compensator for a throttle valve used with electronic engine controllers is also provided.

Abstract: A method for controlling the air-fuel ratio in a natural gas engine having an air-fuel mixing device, comprises: determining a speed set-point and an actual engine speed, determining a fuel command based on said speed set-point and said engine speed and controlling the fuel flow to the air-fuel mixing device in response to said fuel command. An air-fuel control system for natural gas engines, comprises: means to determine a speed set-point and an actual engine speed, a governor control unit for generating a fuel command based on said speed set-point and said actual engine speed and a fuel flow regulator coupled to said governor control unit for regulating the flow of fuel to an air-fuel mixing device in response to said fuel command.