US 5,188,141 AGranted

Vacuum boost valve

AssigneeSiemens Automotive Corporation

InventorsJohn E. Cook, Murray F. Busato, William C. Gillier

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Abstract

A vacuum boost valve senses when the intensity of vacuum from a variable intensity vacuum source is about to drop below a threshold and supplies a boost so that when the intensity of the vacuum source is within a range immediately below the threshold, the intensity of vacuum delivered to a load does not drop below the intensity of the vacuum source and is in fact increased over what it would otherwise be without the boost. The vacuum boost is obtained by using a venturi.

Claims10

Dependent claims

A vacuum boost valve that is responsive to an incipient drop in the intensity of a variable intensity vacuum input to the valve below a threshold level for providing, during the ensuing time that the intensity of the vacuum input remains within a certain range immediately below such threshold level, an intensity of vacuum output that is at least as great as the intensity of vacuum input, and is in fact greater than it otherwise would be without the vacuum boost thus provided, vacuum being measured relative to a reference pressure, said vacuum boost valve comprising:

an inlet port that receives the variable intensity vacuum input;
an outlet port that delivers the vacuum output;
a flow path that extends from a source of pressure higher than the pressure at said inlet port to said inlet port and that comprises a shut-off valve and a venturi in series;
said venturi comprising a low pressure zone at which vacuum is created by certain flow from said source of pressure through said flow path to said inlet port;
a tap at said venturi's low pressure zone that is communicated to said outlet port;
a movable wall and a spring that control said shut-off valve, said spring biasing said shut-off valve open, said movable wall comprising opposite faces that are communicated respectively to a pressure that is correlated with said reference pressure and to said inlet port respectively;
means operatively relating said movable wall, said spring and said shut-off valve such that said shut-off valve is maintained closed by said movable wall so long as the intensity of vacuum at said inlet port is greater than said threshold level, and such that said shut-off valve is maintained open by said spring so long as the intensity of vacuum at said inlet port is less than said threshold level;
and means operatively relating said source of pressure, said shut-off valve, and said venturi in said flow path such that when said shut-off valve is closed, there is no flow through said flow path and the pressure at said tap is essentially equal to the intensity of vacuum at said inlet port, and such that when said shut-off valve is open, there is flow through said flow path that is effective to create at said tap a vacuum whose intensity is at least as great as that of the vacuum input, and is in fact greater than it would otherwise be without the boost that is provided by the venturi.

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Dependencies are inferred from the claim text.

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Abstract

an inlet port that receives the variable intensity vacuum input;
an outlet port that delivers the vacuum output;
a flow path that extends from a source of pressure higher than the pressure at said inlet port to said inlet port and that comprises a shut-off valve and a venturi in series;
said venturi comprising a low pressure zone at which vacuum is created by certain flow from said source of pressure through said flow path to said inlet port;
a tap at said venturi's low pressure zone that is communicated to said outlet port;
a movable wall and a spring that control said shut-off valve, said spring biasing said shut-off valve open, said movable wall comprising opposite faces that are communicated respectively to a pressure that is correlated with said reference pressure and to said inlet port respectively;
means operatively relating said movable wall, said spring and said shut-off valve such that said shut-off valve is maintained closed by said movable wall so long as the intensity of vacuum at said inlet port is greater than said threshold level, and such that said shut-off valve is maintained open by said spring so long as the intensity of vacuum at said inlet port is less than said threshold level;
and means operatively relating said source of pressure, said shut-off valve, and said venturi in said flow path such that when said shut-off valve is closed, there is no flow through said flow path and the pressure at said tap is essentially equal to the intensity of vacuum at said inlet port, and such that when said shut-off valve is open, there is flow through said flow path that is effective to create at said tap a vacuum whose intensity is at least as great as that of the vacuum input, and is in fact greater than it would otherwise be without the boost that is provided by the venturi.

5 more elements