DE102019119944A1 - Valve device for a reciprocating compressor - Google Patents

Abstract

The embodiment according to the invention is a reciprocating compressor for a compressed air supply system in a motor vehicle, with a cylinder head in which a relief system is integrated, by means of which a relief channel in a valve support plate of the cylinder head, which connects a working space of the reciprocating compressor with a space in the cylinder head, can be switched To improve the efficiency of the reciprocating compressor, it is proposed that the relief system comprises a switching device and a lamella, the lamella being attached to the valve support plate on the working space side and being designed in such a way that it can be lifted off the valve support plate in order to open the relief channel, with the lifting of the lamella can take place automatically and / or controlled by means of the relief system.

Description

The invention relates to a reciprocating piston compressor for a compressed air supply system in a motor vehicle, such as a truck, bus or rail vehicle. A reciprocating compressor essentially comprises two areas, the cylinder head area in which the valves are arranged and the crankshaft housing with at least one cylinder which can be moved in a working space, so that a suction stroke movement and a compression stroke movement arise. The reciprocating compressor can be single-stage or multi-stage, in particular two-stage.

The valve device for controlling the air flow is usually assigned to the cylinder head and comprises automatically effective suction valves and pressure valves which are opened and closed by the pressures prevailing in the working space due to the stroke movement of the piston.

The suction stroke of the piston causes a negative pressure in the working chamber of the respective cylinder, so that the associated suction valve opens and the associated pressure valve is closed. Air enters the working chamber of the cylinder or is sucked into the working chamber via the inlet chamber and the inlet channels in the valve carrier plate.

The compression stroke of the piston causes an overpressure in the working chamber of the respective cylinder, so that the associated suction valve closes and the associated pressure valve is opened, whereby compressed air is conveyed from the working chamber of the cylinder via the pressure channel into the downstream compressed air system.

As also from the DE 10 2016 006 358 A1 known, the suction valve is usually designed as a valve lamella, the valve tongue of which is clamped on one side between the cylinder housing and the cylinder head of the reciprocating piston compressor and is guided at its free end with at least one tab in a recess of the cylinder housing. By means of the valve tongue, the inlet openings in the valve support plate, which connect a suction chamber with the working space of the cylinder, can be closed. Furthermore, the valve lamella is designed in such a way that at least one outlet opening is recessed in the valve support plate, which is arranged between the working space of the cylinder and the pressure channel. The pressure valve, via which the outlet opening can be closed, is usually located within the cylinder head area.

The delivery operation of the reciprocating piston compressor continues until the pressure in the main pressure line has reached a predetermined cut-off pressure. The compressor is then switched to idle mode, which reduces the power consumption in idle mode. Such systems are also called relief systems or idle systems.

From the EP 1 650 434 A2 For example, an idle valve is known that opens automatically as soon as the system pressure is reached and an overflow valve has opened. This eliminates the counterpressure of the compressed air system that keeps the idle valve in a closed position. The open idle valve connects the working space with the inlet chamber so that no compression can take place during the compression stroke. One advantage of such a piston compressor is that it is switched off automatically when the target filling pressure is reached in the pressure vessel.

Another idle valve is for example from the DE 10 2013 001 147 A1 known. Here, an idle valve for a relief system is proposed that is held in the closed position by means of a spring and can optionally be switched into an open position by applying pressure. Such systems are also called "externally controlled systems".

All idle systems have in common that in idle operation the working area is connected to another room via a relief duct, so that no compression or only reduced compression occurs.

The object of the invention is to propose a relief system by means of which the energy consumption of a reciprocating compressor can be further reduced.

The object is achieved according to the invention by an embodiment according to claim 1. Further advantageous features of the embodiment according to the invention can be found in the subclaims.

The embodiment according to the invention is a reciprocating compressor for a compressed air supply system in a motor vehicle, with a cylinder head in which a relief system is integrated, by means of which a relief channel in a valve support plate of the cylinder head, which connects a working space of the reciprocating compressor with a space in the cylinder head, can be switched is.

To improve the efficiency of the reciprocating compressor, it is proposed that the relief system comprises a switching device and a lamella, the lamella being attached to the valve carrier plate on the working space side and being designed in such a way that it can be lifted off the valve carrier plate to open the relief channel, the lamella being lifted off automatically and / or controlled by means of the relief system.

The automatic lifting of the lamella results in an enlarged effective duct cross-section, which reduces the inflow resistance of the air into the working space during the suction stroke of the cylinder.

The controlled lifting of the lamella ensures that the compressor is switched to idle mode in which there is no compression.

A preferred embodiment can provide that the cylinder head has an inlet chamber, which can be connected to the working chamber via several inlet channels in the valve support plate and an automatically acting inlet valve lamella formed as a tongue valve, the at least one relief channel being arranged within the inlet channels. In other words, that the at least one relief channel is surrounded by inlet channels.

The lamella can preferably be designed as a tongue valve, a tongue valve being understood to be a lamella that is clamped on one side and closes a channel in the non-actuated position and opens the passage through the channel in the actuated position.

The inlet chamber can preferably be connected to the working space via the inlet channels and the relief channel. The inlet chamber is connected to an air inlet through which, in particular, ambient air enters the inlet chamber. In the inlet chamber, the air is distributed over the inlet ducts and the at least one relief duct and is sucked into the working space via these. The enlarged cross section facilitates the suction stroke movement of the piston, which reduces energy consumption.

Furthermore, the relief system for supporting the lamella can comprise a means for limiting the stroke of the lamella. Particularly with large air volumes that are sucked into the working space during the suction stroke due to the resulting negative pressure, it may be necessary to limit the movement of the lamellae, as is also necessary for the valve lamella in accordance with the StdT. To limit the stroke of the lamella, for example, a delimitation lamella projecting into the working space can be used. So that the dead space remains relatively small, the cylinder can have a corresponding recess for the delimitation lamella. Alternatively, this recess can also be used directly as a means for limiting, so that the lamella hits the recess at least when the lifting movement starts.

Furthermore, the relief system can comprise a relief piston which can be reset by means of a spring element and which can be actuated by means of a control pressure.

In a further embodiment, the reciprocating compressor can be designed as a two-stage compressor, with a preliminary stage and a high-pressure stage, with a relief system and a connecting duct that connects the relief duct of the high-pressure stage with the inlet chamber being provided in the cylinder head for each stage. In the case of multi-stage compressors, the compression stroke of all stages is relieved via a connection that connects the respective working space to the inlet chamber via the relief channel. In this way, when the lamella is in the relief position, ambient air can enter the working area directly even during the suction stroke of the high pressure stage.

In contrast to the lamella of the preliminary stage, the lamella of the relief system of the high pressure stage is designed in such a way that it remains in the closed position during operation during the suction stroke. The lamella of the high-pressure stage or subsequent high-pressure stages is thus designed so that the lamella can only be actively moved into the open position by means of the piston of the relief system.

A method for operating a reciprocating piston compressor for generating compressed air for a utility vehicle is also proposed. The reciprocating compressor has a cylinder head in which a relief system is integrated, by means of which a relief channel in a valve support plate of the cylinder head, which connects a working chamber of the reciprocating compressor with a chamber in the cylinder head, can be switched.

The method is characterized in that during a suction stroke in which a negative pressure is generated in the work space, a lamella of the relief system is automatically or, when the relief system is actuated, forcibly moved into an open position, so that additional air via the inlet chamber and the relief channel is sucked into the work area, or when the relief system is actuated, air can be forced out of the work area via the relief channel. This process is used in a single-stage reciprocating compressor or in the preliminary stage or the first stage of a multi-stage reciprocating compressor.

In an embodiment of the reciprocating piston compressor as a two-stage compressor, a preliminary stage and a high-pressure stage are in series one behind the other switched, with a relief system being provided in the cylinder head for each stage. With such a structure, the lamella of the preliminary stage is automatically moved into the open position during the suction stroke and the lamella of the high-pressure stage can be designed in such a way that it remains in the closed position during the suction stroke.

Furthermore, a connecting channel for connecting the relief systems can be provided in the cylinder head of the two-stage compressor, the relief channel of the high-pressure stage being connected to the inlet chamber of the preliminary stage via the connecting channel, the relief pistons of both relief systems being switched in this way for relief or switching to idle mode of the reciprocating compressor that the slats of both stages are moved into an open position.

• 1 Kolbenseitige Ansicht auf die Ventilplatte eines zweistufigen
• Hubkolbenverdichters mit Entlastungssystem 2 Zylinderkopfseitige Ansicht auf die Ventilplatte eines zweistufigen
• Hubkolbenverdichters mit Entlastungssystem 3 Entlastungssystem der ersten Verdichterstufe im Schnitt
• 4 Entlastungssystem der zweiten Verdichterstufe im Schnitt

The invention is explained in more detail below using an exemplary embodiment. The figures show in detail:

• 1 Piston-side view of the valve plate of a two-stage
• Reciprocating compressor with relief system 2 Cylinder head side view of the valve plate of a two-stage
• Reciprocating compressor with relief system 3 Relief system of the first compressor stage in section
• 4th Relief system of the second compression stage in section

1 shows a piston-side view of the valve support plate 4th a two-stage reciprocating compressor with the relief system that of the cylinder head 12th assigned. The two compressor stages, the preliminary stage 2 and the high pressure stage 3 , have a similar structure but differ slightly in size and function. The basic structure is the same. Both compressor stages have an inlet valve 5a , b , which is fixed on one side and has stop surfaces on the opposite side. For the stop surfaces are in the crankcase 11 Not shown here recesses are provided through which the opening movement of the inlet valves 5a , b is limited. The exhaust ducts 23 are within the outer contour of the inlet valves 5a , b arranged and run partially through recesses in the inlet valves 5a , b . About in the middle of the inlet valves 5a , b , i.e. roughly in the middle of the cylinder's working space 20a , b , on which the inlet valves 5a , b have a recess are those to the relief system 7a , b belonging slats 9a , b arranged. Even the slats 9a , b are clamped on one side.

Due to the different functions of the relief systems 7a , b the valves of the preliminary stage differ 2 and the high pressure stage 3 something. Due to the larger volume of air that occurs during the suction stroke of the cylinder 20a the prepress 2 must be sucked in is the lamella 9a designed in such a way that the valve moves with each suction stroke of the cylinder 20a the prepress 2 opens automatically. A limiting lamella is used to limit the opening movement 22nd provided that a stop for the lamella 9a represents.

2 shows a cylinder head side view of the valve support plate 4th of a two-stage reciprocating compressor with a relief system. In this view, the channels and chambers of the compressor stages can be clearly seen. Both stages 2 , 3 each have an inlet chamber 14a , b and an outlet chamber 15a , b on. The automatically operating outlet valves are located in the outlet chambers 6a , b arranged, which in the closed position, the outlet channels 23 close in the valve support plate and moved into an open position when a definable pressure in the working space is exceeded.

In the area of the inlet chamber 14a the prepress 2 are several channel openings through the valve support plate 4th shown. Part of the openings, the outer semicircle, are the inlet channels 21a that the inlet valve 5a with the inlet valve lamella 18a assigned. During a suction stroke, the air is drawn through the inlet ducts 21a sucked into the work area, the inlet valve lamella 18a moved to an open position. The inlet valve lamella closes during a compression stroke 18a the inlet ducts 21a . Inside the semicircle of the inlet ducts 21a are the relief channels 19a arranged. Their passage is made by means of the lamella 9a of the relief system 7a switched.

The high pressure stage is designed a little differently, here is the relief channel 19b of the relief system 7b arranged in a separate chamber, which is via the connecting channel 13 with the inlet chamber 14a the prepress 2 connected is. The separate channel connection between the outlet chamber is not shown 15a the prepress 2 and inlet chamber 14b the high pressure stage 3 .

3 and 4th show the relief systems 7a , b the prepress 2 and the high pressure stage 3 on average. The general layered structure of the cylinder head 12th is known from the prior art, so that only the channels and chambers essential to the invention are considered further here. The relief system according to the invention 7a for prepress is in 3 and the relief system 7b for the high pressure stage 3 is in 4th shown.

In the case of a single-stage compressor, the relief system can 7a the prepress as described above and in 3 can be used. In the case of a multi-stage, i.e. more than two stages, all stages following the preliminary stage receive the relief system 7b the high pressure stage 2 In a preferred embodiment, a connecting channel can be provided, via which all stages can be connected to the inlet chamber of the preliminary stage. Alternatively, each stage can also comprise a separate channel that is connected to the environment

The special thing about the relief valve of the preliminary stage 2 is the delimitation lamella 22nd , which is designed as a solid component and the lamella 9a supports so that the lamella 9a does not bend too far into the working area, which would lead to excessive bending stress. The cylinder 20a has a recess on the end face in which the delimitation lamellae 22nd immersed when the cylinder is at top dead center, so that the dead space is as small as possible.
The recess is just big enough for the delimitation lamella 22nd and the lamella lying on it when it is open 9a find space in it.

Furthermore the relief piston 10a recognizable in the cylinder head 12th is led. In the position shown, it is in the rest position and is held in this position by a spring. Via the control pressure channel shown 16 can the relief piston 10a are pressurized so that this is in the relief position and the lamella 9a be moved to the open position.

The specialty of the in 4th illustrated relief system 8b the high pressure stage 3 is the design of the lamella 9b which is designed to be so spring-loaded that it can only be removed with the help of the relief piston 10b can be moved into the open position. One suction stroke of the piston 20b the high pressure stage 2 does not cause the slat to move automatically 9b in the open position. Both relief pistons 10a, b are via the control pressure channel shown 16 simultaneously pressurized with compressed air. The piston 20b also has a recess in which the lamella 9b has space in the open position.

List of reference symbols

1

Reciprocating compressors

2

Prepress

3

High pressure stage

4th

Valve support plate

5a, b

Inlet valve

6a, b,

outlet valve

7a, b

Relief system

8a, b

Switching device

9a, b

Lamella

10a, b

Relief piston

11

Crankcase

12

Cylinder head

13

Connection channel

14a, b

Inlet chamber

15a, b

Outlet chamber

16

Control pressure channel

17th

Cooling duct

18a, b

Inlet valve lamella

19a, b

Relief channel

20a, b

Pistons in the working area

21a, b

Inlet port

22nd

Boundary lamella

23

Exhaust ducts

24

Ambient air inlet

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102016006358 A1 [0005]
• EP 1650434 A2 [0007]
• DE 102013001147 A1 [0008]

Claims (12)

Reciprocating piston compressor (1) for a compressed air supply system in a motor vehicle, with a cylinder head (12) in which a relief system (7a, b) is integrated, by means of which a relief duct (19a, b) in a valve support plate (4) of the cylinder head (12), which connects a working space of the reciprocating piston compressor (1) with a space in the cylinder head (12), is switchable, characterized in that the relief system (7a, b) comprises a switching device (8a, b) and a lamella (9a, b), wherein the lamella (9a, b) is attached to the valve support plate (4) on the working space side and can be lifted off the valve support plate (4) to open the relief channel (19a, b), the lifting of the lamella (9a, b) being automatic and / or controlled can be done by means of the relief system. Reciprocating compressor (1) Claim 1 characterized in that the cylinder head (12) has an inlet chamber (14a, b) which, via several inlet channels (21) in the valve support plate (4) and an automatically active inlet valve lamella (18a) designed as a tongue valve, with the working chamber (20a) ) can be connected, the at least one relief channel (19a, b) being arranged within the inlet channels (21). Reciprocating compressor (1) Claim 2 characterized in that the lamella (9a, b) is designed as a tongue valve. Reciprocating compressor (1) Claim 2 characterized in that the inlet chamber (14) can be connected to the working space via the inlet channels (21) and the relief channel (19a, b). Reciprocating compressor (1) Claim 2 , characterized in that the relief system (7a, b) for supporting the lamella (9a, b) comprises a means for limiting the stroke of the lamella (9a, b). Reciprocating compressor (1) Claim 5 , characterized in that the means for limiting the stroke of the lamella (9a) is a limiting lamella (22) protruding into the working space. Reciprocating compressor (1) Claim 1 , characterized in that the relief system (7a, b) comprises a relief piston (10a, b) which can be reset by means of a spring element and which can be actuated by means of a control pressure. Reciprocating compressor (1) Claim 1 , characterized in that the reciprocating compressor (1) is designed as a two-stage compressor with a preliminary stage (2) and a high-pressure stage (3), with a relief system (7a, b) and a connecting duct (13) in the cylinder head (12) for each stage , which connects the relief channel (19b) of the high pressure stage (3) with the inlet chamber (14a) of the preliminary stage (2) are provided. Reciprocating compressor (1) Claim 8 , characterized in that the relief system (7b) of the high-pressure stage (3) has a lamella (9b) which is designed such that the lamella (9b) remains in the closed position during operation during a suction stroke. A method for operating a reciprocating piston compressor (1) for generating compressed air for a commercial vehicle, the reciprocating piston compressor (1) having a cylinder head (12) in which a relief system (7a, b) is integrated, by means of which a relief channel (19a, b ) is switchable in a valve support plate (4) of the cylinder head (12), which connects a working space of the reciprocating compressor (1) with a space in the cylinder head (12), characterized in that during a suction stroke, during which a negative pressure is generated in the working space , a lamella (9a) of the relief system (7a) is moved automatically or, when the relief system (7a) is actuated, forcibly into an open position, so that additional air via the inlet chamber (14a) and the relief channel (19a) into the working space ( 20a) is sucked in or air can be forced out of the working space via the relief channel (19a) during the compression stroke. Procedure according to Claim 10 , characterized in that the reciprocating piston compressor (1) is designed as a two-stage compressor with a preliminary stage (2) and a high-pressure stage (3), a relief system (7a, b) being provided in the cylinder head (12) for each stage (2, 3) The lamella (9a) of the preliminary stage (2) is automatically moved into the open position during a suction stroke and the lamella (9b) of the high pressure stage (3) is designed such that it remains in the closed position during a suction stroke. Procedure according to Claim 10 , characterized in that the two-stage compressor (1) is provided in the cylinder head (12) with a connecting duct (13) for connecting the relief systems (7a, b), the relief duct (19b) of the high-pressure stage (3) via the connecting duct (13) is connected to the inlet chamber (14a) of the preliminary stage (2), the relief pistons (10a, b) of both relief systems (7a, b) being switched in such a way that the lamellae (9a, b) of both stages are connected to relieve the reciprocating piston compressor (1) (2, 3) are moved into an open position.

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