Control mechanism for selectively operating an internal combustion engine on two fuels

Apparatus for controlling operation of an internal combustion engine which is selectively operable using gaseous fuel or liquid fuel, said apparatus comprising means for supplying a gaseous fuel to the engine, means for supplying a liquid fuel to the engine, and control means adapted to be connected to a source of vacuum which is responsive to engine operation and which varies relative to a predetermined level, said control means including a fuel selector switch comprising a first switch element connected to a source of current and movable between a gaseous fuel position and a liquid fuel position, an electrically operated, normally closed gaseous fuel control valve which is located in said gaseous fuel supply means, which is operable between open and closed positions, and which is opened in response to electrical energization thereof, and an electrically operated, normally closed liquid fuel control valve which is located in said liquid fuel supply means, which is operable between open and closed positions, and which is opened in response to electrical energization thereof, said control means being operable, when said selector switch is in said liquid fuel position, to energize said liquid fuel control valve, thereby opening said liquid fuel control valve, said control means also being operable, when said selector switch is in said liquid fuel position and in response to the presence of an amount of vacuum above said predetermined level to energize said gaseous fuel control valve, said control means also being operable, when said selector switch is in said liquid fuel position and in response to the presence of an amount of vacuum below said predetermined level, to deenergize said gaseous fuel control valve, and thereby close said gaseous fuel control valve, and thereafter to retain said gaseous fuel control valve deenergized regardless of vacuum variation, said control means also being operable, when said selector switch is in said gaseous fuel position, to deenergize said liquid fuel control valve, thereby closing said liquid fuel control valve, said control means also being operable, when said selector switch is in said gaseous fuel position and in response to an amount of vacuum above said predetermined level, to deenergize said gaseous fuel control valve, thereby closing said gaseous fuel control valve, and said control means also being operable, when said selector switch is in said gaseous fuel position and in response to an amount of vacuum below said predetermined level, to energize said gaseous fuel control valve and thereby open said gaseous fuel control valve, and thereafter to retain energization of said gaseous fuel control valve regardless of vacuum variation.

Apparatus for controlling operation of an internal combustion engine which is selectively operable using gaseous fuel or liquid fuel, said apparatus comprising means for supplying a gaseous fuel to the engine, means for supplying a liquid fuel to the engine, and control means including a vacuum operated switch adapted to be connected to a source of vacuum which is responsive to engine operation and which varies relative to a predetermined level, said switch being biased so that, in the absence of a vacuum condition above a pre-determined level, said switch is closed, said control means also including a fuel selector switch movable between a gaseous fuel position and a liquid fuel position, an electrically operated, normally closed gaseous fuel control valve which is located in said gaseous fuel supply means, which is operable between open and closed positions, and which is opened in response to electrical energization thereof, and an electrically operated, normally closed liquid fuel control valve which is located in said liquid fuel supply means, which is operable between open and closed positions, and which is opened in response to electrical energization thereof, said control means being operable, when said selector switch is in said liquid fuel position, to energize said liquid fuel control valve, thereby opening said liquid fuel control valve, said control means also being operable, when said selector switch is in said liquid fuel position and in response to the presence of an amount of vacuum above said predetermined level to energize said gaseous fuel control valve, said control means also being operable, when said selector switch is in said liquid fuel position and in response to the presence of an amount of vacuum below said predetermined level, to deenergize said gaseous fuel control valve, and thereby close said gaseous fuel control valve, and thereafter to retain said gaseous fuel control valve deenergized regardless of vacuum variation, said control means also being operable, when said selector switch is in said gaseous fuel position, to deenergize said liquid fuel control valve, thereby closing said liquid fuel control valve, said control means also being operable, when said selector switch is in said gaseous fuel position and in response to an amount of vacuum above said predetermined level, to deenergize said gaseous fuel control valve, thereby closing said gaseous fuel control valve, and said control means also being operable, when said selector switch is in said gaseous fuel position and in response to an amount of vacuum below said predetermined level, to energize said gaseous fuel control valve and thereby open said gaseous fuel control valve, and thereafter to retain energization of said gaseous fuel control valve regardless of vacuum variation.

Engine control apparatus including an internal combustion engine which includes an intake manifold which is selectively operable using gaseous fuel, means for supplying a gaseous fuel to said engine, means for supplying a liquid fuel to said engine, and control means including a vacuum operated switch adapted to be connected to a source of vacuum which is responsive to engine operation and which varies relative to a predetermined level, said switch being biased so that, in the absence of a vacuum condition alone the predetermined level, said switch is closed, a conduit communicating between said engine manifold and said vacuum switch, said control means also including a fuel selector switch movable between a gaseous fuel position and a liquid fuel position, an electrically operated, normally closed gaseous fuel control valve which is located in said gaseous fuel supply means, which is operable between open and closed positions, and which is opened in response to electrical energization thereof, and an electrically operated, normally closed liquid fuel control valve which is located in said liquid fuel supply means, which is operable between open and closed positions, and which is opened in response to electrical energization thereof, said control means being operable, when said selector switch is in said liquid fuel position, to energize said liquid fuel control valve, thereby opening said liquid fuel control valve, said control means also being operable, when said selector switch is in said liquid fuel position and in response to the presence of an amount of vacuum above said predetermined level, to energize said gaseous fuel control valve, said control means also being operable, when said selector switch is in said liquid fuel position and in response to the presence of an amount of vacuum below said predetermined level, to deenergize said gaseous fuel control valve, and thereby close said gaseous fuel control valve, and thereafter to retain said gaseous fuel control valve deenergized regardless of vacuum variation, said control means also being operable, when said selector switch is in said gaseous fuel position, to deenergize said liquid fuel control valve, thereby closing said liquid fuel control valve, said control means also being operable, when said selector switch is in said gaseous fuel position and in response to an amount of vacuum above said predetermined level, to deenergize said gaseous fuel control valve, thereby closing said gaseous fuel control valve, and said control means also being operable, when said selector switch is in said gaseous fuel position and in response to an amount of vacuum below said predetermined level, to energize said gaseous fuel valve and thereby open said gaseous fuel control valve, and thereafter to retain energization of said gaseous fuel control valve regardless of vacuum variation.

Apparatus for controlling operation of an internal combustion engine which is selectively operable using gaseous fuel or liquid fuel, said apparatus comprising a gaseous fuel supply line extending between the engine and a source of gaseous fuel, a liquid fuel supply line extending between the engine and a source of liquid fuel, and means for controlling supply to the engine of the gaseous fuel and the liquid fuel, said control means including an operator controlled fuel selector switch movable between a gaseous fuel position and a liquid fuel position, and a vacuum operated switch which is biased so that, in the absence of a vacuum condition above a pre-determined level, said vacuum switch is closed, said control means being operable, following prior engine operation with gaseous fuel and in response to movement of said fuel selector switch from said gaseous fuel position to said liquid fuel position, for permitting liquid fuel flow through said liquid fuel supply line, for permitting continued gaseous fuel flow through said gaseous fuel supply line until initiation of liquid fuel combustion, and thereafter preventing further gaseous fuel flow through said gaseous fuel supply line until repositioning of said fuel selector switch to said gaseous fuel position, said control means also being operable following prior engine operation with liquid fuel and in response to movement of said fuel selector switch from said liquid fuel position to said gaseous fuel position for preventing further liquid fuel flow through said liquid fuel supply line, for preventing gaseous fuel flow through said gaseous fuel supply line until termination of liquid fuel combustion, and for thereafter permitting gaseous fuel flow through said gaseous fuel supply line until repositioning of said fuel selector switch to said liquid fuel position.

An engine control apparatus including an internal combustion engine which includes an intake manifold and which is selectively operable using gaseous fuel or liquid fuel, a gaseous fuel supply line extending between said engine and a source of gaseous fuel, a liqiud fuel supply line extending between said engine and a source of liquid fuel, and means for controlling supply to said engine of the gaseous fuel and the liquid fuel, said control means including an operator controlled fuel selector switch movable between a gaseous fuel position and a liquid fuel position, a vacuum operated switch which is biased so that, in the absence of a vacuum condition above a pre-determined level, said vacuum switch is closed, and a conduit communicating between said engine manifold and said vacuum switch, said control means being operable, following prior engine operation with gaseous fuel and in response to movement of said fuel selector switch from said gaseous fuel position to said liquid fuel position, for permitting liquid fuel flow through said liquid fuel supply line, for permitting continued gaseous fuel flow through said gaseous fuel supply line until initiation of liquid fuel combustion, and thereafter preventing further gaseous fuel flow through said gaseous fuel supply line until repositioning of said fuel selector switch to said gaseous fuel position, said control means also being operable, following prior engine operation with liquid fuel and in response to movement of said fuel selector switch from said liquid fuel position to said gaseous fuel position, for preventing further liquid fuel flow through said liquid fuel supply line, for preventing gaseous fuel flow through said gaseous fuel supply line until termination of liquid fuel combustion, and for thereafter permitting gaseous fuel flow through said gaseous fuel supply line until repositioning of said fuel selector switch to said liquid fuel position.