CN118224065A - Piston compressor with idle function - Google Patents

Abstract

A reciprocating piston compressor for a compressed air supply system in a motor vehicle is proposed, having a cylinder head, in which a pressure relief system is integrated, comprising a first pressure relief valve corresponding to a first booster stage and a second pressure relief valve corresponding to a second booster stage, wherein the pressure relief valves can be switched from a compressor operating position into an idle position. According to the invention, in the compressor operating position, the first pressure relief valve closes a first connection between the first piston chamber and the inlet channel of the compressor stage, and the second pressure relief valve closes a second connection between the piston chamber of the second compressor stage and the intermediate chamber.

Description

Piston compressor with idle function

Technical Field

The present invention relates to a piston compressor with an idle function, which is suitable for pressurizing a compressible working medium, in particular air, for a compressed air supply in a motor vehicle.

Background

Piston compressors or booster compressors or air compressors are used for compressing gases, such as air, which are used as working medium for the operation of different units. Furthermore, the supercharger can be used in a motor vehicle. In operation, such a supercharger is used, for example, to fill compressed air into a compressed air container until a predetermined pressure level is reached in the pressure container.

Piston turbochargers are essentially composed of a main body, in which one or two booster stages are usually provided. A cylinder head is arranged above the supercharger stage. Valves and pipes are provided in the cylinder head for air guiding and air cooling.

In operation, ambient air is drawn into the first booster stage through the intake passage, boosted, and then directed through the intermediate passage into the second booster stage where it is further boosted. In a two-stage piston booster, compressed air is then introduced into a compressed air container by an air treatment unit.

In order to minimize the drive energy required and to reduce the starting torque, it is known to provide the piston booster with means for switching into idle operation. It may be a valve connection or a connector may be arranged between the drive device and the piston booster.

A piston booster with an additional valve in the inlet chamber of the first booster stage is known from EP 1,650,434 A1. The controllable pressure conditions in the discharge chamber of the final booster stage result in the additional valve opening in the idle operation and closing in the compressed air operation. In the open state of the additional valve, no compression of the air can take place in the first and second compressor stages.

A piston booster with two booster stages is known from DE 10 2015 225 065 A1. Two switchable valves are arranged in the cylinder head, wherein each booster stage is equipped with a valve, so that each stroke chamber can be connected to the inlet channel of the first stage via the corresponding valve. The valve is not compressible when opened.

Common to all idling systems is that the working space is connected to a further space by a pressure relief channel during idling operation in order to not compress or to reduce compression.

Disclosure of Invention

The invention aims to provide an alternative pressure release system.

The object is achieved according to the application by a reciprocating piston compressor for a compressed air supply system in a motor vehicle. Other advantageous embodiments of the application are given in the present application.

The invention provides a reciprocating piston compressor for a compressed air supply system in a motor vehicle, comprising a cylinder head, in which a pressure relief system is integrated, comprising a first pressure relief valve corresponding to a first booster stage and a second pressure relief valve corresponding to a second booster stage, wherein the pressure relief valves can be switched from a compressor operating position into an idle position.

According to the invention, in the compressor operating position, the first pressure relief valve closes a first connecting channel between the first piston chamber of the booster stage and the inlet channel, and the second pressure relief valve closes a second connecting channel between the piston chamber of the second booster stage and the intermediate chamber.

Furthermore, the first and the second pressure relief valve can be designed as self-closing valves, wherein the pressure relief valves each comprise a spring by means of which the pressure relief valve is moved into the compressor operating position. If not, the pressure relief valve is closed.

Preferably, both the first and second pressure relief valves are connected to the control passage such that both pressure relief valves can be switched simultaneously through the control air port. Alternatively, the switching of the valves may be performed electromagnetically or hydraulically. The intermediate chamber may furthermore have a volume which corresponds to 0.5 to 5 times the volume of the second stroke chamber.

In a preferred embodiment, the intermediate chamber can be a partial section of the intermediate channel, which connects the outlet valve of the first booster stage with the inlet valve of the second booster stage. Alternatively, the intermediate chamber may be a separate chamber which serves only to enlarge the second piston chamber in idle operation.

Preferably cooling means are provided to cool the air in the intermediate channel and/or the intermediate chamber.

Drawings

The invention is elucidated below on the basis of the drawings. In the accompanying drawings:

Fig. 1 shows a reciprocating piston compressor in a delivery operation

Fig. 2 shows the reciprocating piston compressor in idle operation.

Detailed Description

The figures show two operating states of a reciprocating piston compressor according to the invention. One is a delivery operation, in which compressed air is delivered into the pressure channel 14. One is an idle operation, in which no compressed air is fed into the pressure channel.

The reciprocating piston compressor 1 is a two-stage compressor having a first and a second booster stage 2, 3. The two pressure release valves 9 and 10 are arranged in a common cylinder head 21. The drawings are simplified sketches in which more details can be obtained from the prior art.

In the delivery operation, ambient air is sucked into the first piston chamber 18 through the suction channel 4 and the inlet valve 5 when the piston moves downwards. If the piston of the first booster stage 2 moves upwards, air is compressed and fed through the outlet valve 6 into the intermediate channel 13 and through the inlet valve 7 of the second booster stage 3 into the second piston chamber 19. Here, the piston in the second piston chamber 19 moves downward. When the piston is subsequently moved upwards, the air is further compressed and fed through the discharge valve 8 into the pressure channel 14.

The first pressure relief valve 9 and the second pressure relief valve 10 are held in the closed position by means of springs 20a, b during the delivery operation. Intermediate cooling of the air is performed in the intermediate channel 13 between the first and second booster stages in order to increase efficiency, volume efficient use and reduce the temperature of the boosted air.

The inlet valve 7 of the next higher stage (second stage) and the outlet valve 6 of the previous stage (first stage) are simultaneously switched.

The intermediate channel 13 is a channel formed by the pressure chamber of the first booster stage 2 and the inlet chamber of the second booster stage 3.

Fig. 2 now shows an idle operation, in which the pressure release valves 9 and 10 are acted upon by control air 11 via a control channel 12, so that the valves 9 and 10 are moved into the open position against the spring force of the springs 20a, b.

When the first pressure release valve 9 is open, the first booster stage 2 is directly connected to the environment via the suction channel 4, which results in a direct ventilation of the first piston chamber.

For the connection of the second pressure release valve 10, a first solution is shown in fig. 2, wherein at least one part of the intermediate channel 13 is formed by an intermediate chamber 13 a. The second pressure relief valve 10 is integrated into the intermediate channel 13 in such a way that, when the second pressure relief valve 10 is open, a second connecting channel 17 between the second piston chamber 19 and the intermediate channel 13 is open.

In the solution shown, the intermediate channel 13 also forms an intermediate chamber 13a. The volume of the intermediate channel 13 or the intermediate chamber 13a forms a pressure relief volume, wherein the pressure of the compressed air in the pressure relief volume is dependent on the point in time when the pressure relief valve 9, 10 is opened.

However, another solution may also be a separate intermediate chamber coupled only with the second pressure relief valve 10, so that the connection between the second piston chamber 19 and the intermediate chamber can be opened by the second pressure relief valve.

In both solutions, compressed air can no longer enter the pressure channel 14 through the discharge valve 8 of the second booster stage 3 and from there into the APU/boiler when the second pressure release valve 10 is open. Furthermore, due to the high pressure in the pressure channel, the outlet valve is safely closed, so that no pressure drop occurs during idle operation. This allows a faster switching to the delivery mode, since the line does not have to be refilled at this time.

As long as the pressure release valve 10 remains open, the cylinder volume of the second piston chamber 19 is pressed into the intermediate chamber 13a and again withdrawn. The discharge valve 6 of the first booster stage 2 remains closed here, since the connection between the first piston chamber 18 and the environment is simultaneously released by the first pressure release valve 9, so that no compressed air can be pressed from the first booster stage 2 into the intermediate channel 13 or the intermediate chamber 13 a.

The volume of the intermediate chamber may be fully used for the pressure relief of the second booster stage.

The present invention combines the functions of the intermediate channels 13, 13a between the cylinders of the multi-stage compressor. The intermediate channels 13, 13a serve for pressure relief of the second booster stage 3 in idle operation and for improved cooling of the air precompressed in the first booster stage 2 in compression operation.

Furthermore, the intermediate channel 13 together with the intermediate chamber 13a in the compression-operating position of the pressure release valves 9, 10 serves also for: the pre-pressure from the first booster stage 2 is provided for loading of the second booster stage 3.

For improving the air quality (filling degree), the intermediate chamber 13a and the intermediate channel 13 may be provided with cooling means or cooling channels for cooling the compressed air before the next compression.

The pressure release valves 9, 10 may alternatively be hydraulically or electromagnetically controlled.

List of reference numerals:

1. Compressor with a compressor body having a rotor with a rotor shaft

2. First booster stage

3. Second booster stage

4. Suction channel

5. Inlet valve

6. Discharge valve

7. Inlet valve

8. Discharge valve

9. First pressure release valve

10. Second pressure release valve

11. Controlling air

12. Control channel

13. Intermediate channel

13A intermediate chamber

14. Pressure channel

16. First connecting channel

17. Second connecting channel

18. First piston chamber

19. Second piston chamber

20A, b spring

21. Cylinder head

Claims (6)

1. Reciprocating piston compressor (1) for a compressed air supply system in a motor vehicle, having a cylinder head (21) in which a pressure relief system is integrated, comprising a first pressure relief valve (9) corresponding to a first booster stage (2) and a second pressure relief valve (10) corresponding to a second booster stage (10), wherein the pressure relief valves (9, 10) can be switched from a compressor operating position into an idle position, characterized in that in the compressor operating position the first pressure relief valve (9) closes a first connecting channel (16) between a first piston chamber (18) of the first booster stage (2) and an inlet channel (5), and the second pressure relief valve (10) closes a second connecting channel (17) between a second piston chamber (19) of the second booster stage (3) and an intermediate chamber (13 a).

2. Reciprocating piston compressor (1) according to claim 1, characterized in that the first and second pressure relief valves (9, 10) are self-closing valves comprising springs (20 a, b) by means of which the pressure relief valves (9, 10) are moved into the compressor operating position.

3. Reciprocating piston compressor (1) according to claim 1 or 2, characterized in that both the first and the second pressure relief valve (9, 10) are connected to the control channel (12) such that both pressure relief valves can be switched simultaneously through the control air port (11).

4. Reciprocating piston compressor (1) according to claim 1, characterized in that the intermediate chamber (13 a) has a volume corresponding to 0.5 to 5 times the volume of the second piston chamber (19).

5. Reciprocating piston compressor (1) according to claim 1, characterized in that the intermediate chamber (13 a) is a partial section of an intermediate channel (13) connecting the outlet valve (6) of the first booster stage (2) and the inlet valve (7) of the second booster stage (3).

6. Reciprocating piston compressor (1) according to claim 2, characterized in that cooling means are provided by which the air in the intermediate channel (13) and/or the intermediate chamber (13 a) is cooled.