Anti-afterburn device for engine having air pump

Claim 2

An anti-afterburn device for an engine having an air pump, comprising a control valve for controlling air supply, a pressure differential means dividing a housing into first and second chambers and being connected to said control valve, a spring urging said control valve in one direction, first and second conduits connecting respectively said chambers with an intake manifold of the engine, a first orifice provided in one of said conduits, a separate air pressure source, and a first three-way valve provided in said first conduit and connected to said first chamber to urge the pressure differential means opposite to that of the spring by supply of an air pressure to the first chamber, said first three-way valve being adapted to selectively supply an intake manifold negative pressure or the air pressure from the separate pressure source into said first chamber, said control valve being operable to reduce the air supply upon abrupt pressure change in said intake manifold or upon supply of the air pressure from the separate pressure source, said first orifice being provided in said second conduit, and a first check valve is located in parallel with said first orifice, said check valve permitting a communication only from said second chamber to the intake manifold.

Claim 3

An anti-afterburn device for an engine having an air pump, comprising a control valve for controlling air supply, a pressure differential means dividing a housing into first and second chambers and being connected to said control valve, a spring urging said control valve in one direction, first and second conduits connecting respectively said chambers with an intake manifold of the engine, a first orifice provided in one of said conduits, a separate air pressure source, and a first three-way valve provided in said first conduit and connected to said first chamber to urge the pressure differential means opposite to that of the spring by supply of an air pressure to the first chamber, said first three-way valve being adapted to selectively supply an intake manifold negative pressure or the air pressure from the separate pressure source into said first chamber, said control valve being operable to reduce the air supply upon abrupt pressure change in said intake manifold or upon supply of the air pressure from the separate pressure source, said first orifice being provided in said first conduit and said first three-way valve is located in said first conduit between said orifice and said first chamber, a first check valve located in parallel with said first orifice, said check valve permitting a communication only from the intake manifold to the first chamber, and a second orifice provided in said second conduit, a second check valve located in parallel with said second orifice, said second check valve permitting a communication only from said second chamber to the intake manifold.

Claim 4

An anti-afterburn device for an engine having an air pump, comprising a control valve for controlling air supply, a pressure differential means dividing a housing into first and second chambers and being connected to said control valve, a spring urging said control valve in one direction, first and second conduits connecting respectively said chambers with an intake manifold of the engine, a first orifice provided in one of said conduits, a separate air pressure source, and a first three-way valve provided in said first conduit and connected to said first chamber to urge the pressure differential means opposite to that of the spring by supply of an air pressure to the first chamber, said first three-way valve being adapted to selectively supply an intake manifold negative pressure or the air pressure from the separate pressure source into said first chamber, said control valve being operable to reduce the air supply upon abrupt pressure change in said intake manifold or upon supply of the air pressure from the separate pressure source, said first orifice being provided in said first conduit and said first three-way valve is located in said first conduit between said orifice and said first chamber, a first check valve located in parallel with said first orifice, said check valve permitting a communication only from the intake manifold to the first chamber, and a second orifice provided in said second conduit, a second check valve located in parallel with said second orifice, said second check valve permitting a communication only from said second chamber to the intake manifold.

Claim 5

An anti-afterburn device according to claim 2, wherein a second three-way valve is located in series with said second orifice and is in parallel with said second check valve, said second three-way valve being adapted to selectively communicate between the intake manifold and the second chamber via a reservoir tank and a check valve arranged in series or between the second orifice and the second chamber and being operated with said first three-way valve.

Claim 6

An anti-afterburn device according to claim 3, wherein each three-way valve is a solenoid valve and is controlled by a controller actuated by a sensor means.

Claim 7

An anti-afterburn device for an engine having an air pump, comprising a control valve for controlling air supply, a pressure differential means dividing a housing into first and second chambers and being connected to said control valve, a spring urging said control valve in one direction, first and second conduits respectively connected to said first and second chambers, a separate air pressure source, a four-way valve means connected to said first conduit and communicating with said first chamber for supply of an air pressure to the first chamber to urge the pressure differential means in a direction opposite to that of the spring, said four-way valve means also being connected to said second conduit, to a third conduit which is connected to an intake manifold and to a fourth conduit which is in communication with the air pressure from said separate pressure source, first and second check valves respectively provided in by-pass passages communicating said third conduit with said first conduit and with said second conduit, and first and second orifices provided in said first conduit and said second conduit between said four-way valve means and said by-pass passages respectively, said four-way valve means being operated selectively to one position in which a communication between said first, second and third conduits is permitted but closing said fourth conduit and to the other position in which a communication between said first and fourth conduits is permitted but closing said second and third conduits.

Claim 8

An anti-afterburn device for an engine having an air pump, comprising a control valve for controlling air supply, a pressure differential means dividing a housing into first and second chambers and being connected to said control valve, a spring urging said control valve in one direction, first and second conduits respectively connected to said first and second chambers, a separate air pressure source, a four-way valve means connected to said first conduit and communicating with said first chamber for supply of an air pressure to the first chamber to urge the pressure differential means in a direction opposite to that of the spring, said four-way valve means also being connected to said second conduit, to a third conduit which is connected to an intake manifold and to a fourth conduit which is in communication with the air pressure from said separate pressure source, first and second check valves respectively provided in by-pass passages communicating said third conduit with said first conduit and with said second conduit, and first and second orifices provided in said first conduit and said second conduit between said four-way valve means and said by-pass passages respectively, said four-way valve means being operated selectively to one position in which a communication between said first, second and third conduits is permitted but closing said fourth conduit and to the other position in which a communication between said first and fourth conduits is permitted but closing said second and third conduits.

Claim 9

An anti-afterburn device according to claim 5, wherein said four-way valve means is a solenoid valve and is controlled by a controller actuated by an atmospheric temperature sensor, a high temperature sensor or a speed sensor.