WO2018054878A1

WO2018054878A1 - Screw compressor system for a utility vehicle

Info

Publication number: WO2018054878A1
Application number: PCT/EP2017/073579
Authority: WO
Inventors: Gilles Hebrard; Jean-Baptiste Marescot; Jörg MELLAR; Thomas Weinhold
Original assignee: Knorr-Bremse Systeme Für Nutzfahrzeuge
Priority date: 2016-09-21
Filing date: 2017-09-19
Publication date: 2018-03-29
Also published as: KR20190045946A; CN109964038A; EP3516230A1; US20190338778A1; DE102016011507A1; BR112019005057A2; JP2019536942A

Abstract

The invention relates to a screw compressor system (100) for a utility vehicle, comprising at least one screw compressor (10), at least one screw compressor drive and at least one control and/or regulation unit (110). Said control and/or regulation unit (110) is connected to the screw compressor drive and is designed and configured such that it monitors, when the screw compressor (10) is in operation, the ratio of idle time and switched on time of the screw compressor drive and this ratio controls and regulates to a predetermined range.

Description

DESCRIPTION

The present invention relates to a screw compressor system for a commercial vehicle having at least one screw compressor with at least one control and / or regulating unit for drive control and / or regulation of the vehicle

Screw compressors, Screw compressors for commercial vehicles are already known from the prior art. Such screw compressors are used to provide the necessary compressed air for, for example, the braking system of the commercial vehicle.

In this context, in particular oil befülite compressors, especially screw compressors are known in which poses the task, the

To regulate oil temperature. This is usually accomplished by having an external oil cooler connected to the oil-filled compressor and the oil circuit via a thermostatic valve. The oil cooler is here

Heat exchanger having two separate circuits, wherein the first circuit for the hot liquid, so the compressor oil is provided and the second for the cooling liquid. As a coolant, for example, air,

Water mixtures can be used with an antifreeze or other oil. This oil cooler must then with the compressor oil circuit through pipes or

Hoses are connected and the oil circuit must be secured against leaks.

This external volume must also be filled with oil, so that the total amount of oil is increased. This increases the system inertia. In addition, the oil cooler must be mechanically housed and secured, either by surrounding brackets or by a separate

Holder, which requires additional means of improvement, but also space. From US 4,780,061 a screw compressor with an integrated oil cooling is already known. Furthermore, DE 37 17 493 A1 discloses a arranged in a compact housing screw compressor plant, the oil cooler on the Eiektromotor of the

Has screw compressor.

A generic screw compressor is already known, for example, from DE 10 2004 060 417 B4.

It is the object of the present invention to further develop a screw compressor system of the type mentioned in an advantageous manner, in particular

in that the drive control and / or regulation of the

Screw compressor simplified and can be configured reliably.

This object is achieved by a screw compressor system with the features of claim 1. Thereafter, it is provided that a

Screw compressor system for a commercial vehicle with at least one

Screw compressor, at least one screw compressor drive and

at least one control and / or regulating unit is provided, wherein the control and / or regulating unit is in communication with the screw compressor drive, wherein the control and / or regulating unit is arranged and configured so that it is the ratio of service life during operation of the screw compressor and Einschaitzeit the screw compressor drive monitors and controls this ratio to a predetermined range and / or einregelt.

The invention is based on the idea that by the ratio of

Service life and Einschaitzeit also significantly the temperature of

Compressor is determined. Depending on the design of the screw compressor, it suffices, by controlling the ratio of service life and Einschaitzeit to a predetermined range, the screw compressor in a very tight

Operating temperature range to lead. The intermeshing screws and the guided through the screw compressor oil and the compressed air lead to a heat development, so that by appropriately choosing the

Ratio of service life and on-time of the screw compressor stroke also simultaneously controlled and / or adjusted the heat of the screw compressor, i. can be adjusted.

For example, it can be provided that the control and / or regulating unit part of the screw compressor so either the

Screw compressor or the screw compressor drive is. As a result, a compact structure is formed and it is not necessary to have access to external components.

In principle, however, it is also conceivable that the control and / or regulating unit is part of an air treatment system of the commercial vehicle. Here is already a corresponding control available, which can be easily shared.

It is also conceivable that the control and / or regulating unit is part of an engine or vehicle control of the commercial vehicle. Again, it would be possible to access an already existing component of the commercial vehicle.

In principle, however, it is also conceivable that the control and / or regulating unit is designed as a separate control and / or regulating unit. This allows, for example, a simple installation and also a simple exchange or

simple upgrades.

Furthermore, it can be provided that the range is selected such that there is a ratio of service life to switch-on time, in which the switch-on time is approximately 20 to 50%, in particular> 30%. This ratio of service life to switch-on time with a switch-on time between approximately 20 to 40%, in particular at> 30%, has proven to be comparatively favorable in order to be able to adhere the operating temperature substantially constant. In addition, there is an advantage that by ensuring a ratio of service life to on-time with a turn-on time > 30% the operating temperature remains high enough to avoid moisture or condensation inside the screw compressor.

In addition, it can be provided that the control and / or regulating unit is designed and configured such that it determines the rotational speed of the

Screw compressor drive such effects that the ratio of service life and turn-on of the screw compressor drive is kept within the specified range. In essence, it is assumed here that over the

Total running time of the screw compressor a certain amount of compressed air

be provided and that by the definition or limitation or

Increase in the speed of the screw compressor drive over the entire run time with the same compressed air production and the ratio of service life and

On time of the screw compressor drive influenced and thus in the

predetermined range can be maintained.

In particular, it may be provided that the control and / or regulating unit is designed and configured such that it controls the rotational speed of the

Screw compressor drive always keeps above a minimum speed. These

Possibility to keep the speed above a minimum speed, based on the idea that from a certain minimum speed only a limitation of the power loss occurs and the screw compressor drive requires less energy to produce a certain amount of compressed air. In other words, the efficiency of the screw compressor can be improved as a result. For example, it is known that below minimum speeds of about 1, 500 to 2,500 revolutions per minute, the power loss can rise sharply, so that a

Fall below these minimum speeds should be avoided if possible.

Further details and advantages of the invention will now be based on a in the

Drawings illustrated embodiment will be explained in more detail,

Show it: Fig. 1 is a schematic sectional view through a screw compressor according to the invention; and

Fig. 2 is a schematic drawing on the Schraubenkompressorsytem

according to the present invention.

Fig. 1 shows a schematic sectional view of a screw compressor 10 in the sense of an embodiment of the present invention. The screw compressor 10 has a mounting flange 12 for mechanical attachment of the screw compressor 10 to an electric motor not shown here.

Shown, however, is the input shaft 14, via which the torque from the electric motor to one of the two screws 16 and 18, namely the screw 16 is transmitted.

The screw 18 meshes with the screw 16 and is driven by this.

The screw compressor 10 has a housing 20 in which the essential components of the screw compressor 10 are housed.

The housing 20 is filled with oil 22.

Air inlet side is on the housing 20 of the screw compressor 10 a

Inlet port 24 is provided. The inlet nozzle 24 is designed such that 'an air filter 26 is disposed on it. In addition, a Luftetnlass 28 is provided radially on the air inlet port 24.

In the area between inlet port 24 and the point at which the inlet port 24 attaches to the housing 20, a spring-loaded valve core 30 is provided, designed here as an axial seal.

This valve insert 30 serves as a check valve. Downstream of the valve core 30, an air supply channel 32 is provided, which supplies the air to the two screws 16, 18. On the output side of the two screws 18, 18, an air outlet pipe 34 is provided with a riser 36.

In the region of the end of the riser 36, a temperature sensor 38 is provided, by means of which the oil temperature can be monitored.

Furthermore, a holder 40 for an air de-oiling element 42 is provided in the air outlet area.

The holder 40 for the air de-oiling element has the air de-oiling element 42 in the mounted state in the region facing the bottom {as also shown in FIG. 1).

Further provided in the interior of the air de-oiling element 42 is a corresponding filter screen or known filter and oil-separating devices 44, which are not specified in detail. in the central upper area, relative to the assembled and ready-to-use state (ie as shown in FIG. 1), the holder for the air de-oiling element 40 has a

Air outlet opening 46 leading to a check valve 48 and a '

Minimum pressure valve 50 lead. The check valve 48 and the minimum pressure valve 50 may also be formed in a common, combined valve.

Following the check valve 48, the air outlet 51 is provided.

The air outlet 51 is connected to correspondingly known compressed air consumers in the rule.

To return the oil 22 located and separated in the air de-oiling element 42 back into the housing 20, a riser 52 is provided, the output of Holder 40 for the Luftentölelement 42 when passing into the housing 20 has a filter and check valve 54.

Downstream of the filter and check valve 54, a nozzle 56 is provided in a housing bore. The oil return line 58 leads back approximately in the middle region of the screw 16 or the screw 18 in order to supply oil 22 again.

In the assembled state located in the bottom portion of the housing 20 is a

Oil drain plug 59 is provided. About the oil drain plug 59, a

corresponding oil drain opening are opened, via which the oil 22 can be drained.

In the lower region of the housing 20 and the projection 60 is present, to which the oil filter 62 is attached. Via an oil filter inlet channel 64, which is arranged in the housing 20, the oil 22 is first passed to a thermostatic valve 66.

Instead of the thermostatic valve 66, a control and / or

Control means may be provided, by means of which the oil temperature of the oil 22 located in the housing 20 can be monitored and adjusted to a desired value.

Downstream of the thermostatic valve 66 is then the oil inlet of the oil filter 62, the oil 22 via a central return line 68 back to the screw 18 or screw 16, but also to the oil-lubricated bearing 70 of the shaft 14 leads. In the region of the bearing 70, a nozzle 72 is provided, which is provided in the housing 20 in connection with the return line 68.

The cooler 74 is connected to the projection 60.

In the upper region of the housing 20 (relative to the mounted state) there is a safety valve 76, via which an excessive pressure in the housing 20 can be reduced. Before the minimum pressure valve 50 is a bypass line 78, which leads to a relief valve 80. About this relief valve 80 mitteis a

Connection with the air supply 32 is controlled, air can be returned to the region of the air inlet 28. In this area, a venting not shown in detail and also a nozzle (diameter reduction of the feeding line) may be provided.

In addition, approximately at the level of the conduit 34 in the outer wall of the housing 20, an oil level sensor 82 may be provided. This oil level sensor 82 may be, for example, an optical sensor and arranged and configured so that it can be detected by the sensor signal, whether the oil level in operation above the oil level sensor 82 or if the oil level sensor 82 is exposed and thereby the oil level has fallen accordingly. In connection with this monitoring, an alarm unit can also be provided which outputs or forwards an appropriate error message or warning message to the user of the system.

The function of the screw compressor 10 shown in FIG. 1 is as follows:

Air is supplied via the air inlet 28 and passes through the check valve 30 to the screws 16, 18, where the air is compressed. The compressed air-oil mixture, which rises by a factor of between 5 and 16 times compression after the screws 16 and 18 through the outlet conduit 34 via the riser 36, is blown directly onto the temperature sensor 38.

The air, which still partly carries oil particles, is then guided via the holder 40 into the air de-oiling element 42 and, provided the corresponding minimum pressure is reached, enters the air outlet line 51.

The oil 22 located in the housing 20 is maintained at the operating temperature via the oil filter 62 and possibly via the heat exchanger 74. If no cooling is necessary, the heat exchanger 74 is not used and is not switched on.

The corresponding connection via the thermostatic valve 88. After the purification in the oil filter 64 is via the line 68 oil of the screw 18 or the

Screw 16, but also fed to the bearing 72. The screw 16 or the screw 18 is supplied via the return line 52, 58 with oil 22, here is the purification of the oil 22 in Luftentölelement 42. About the electric motor not shown in detail, which transmits its torque via the shaft 14 to the screw 16, which in turn meshes with the worlds 18, the screws 16 and 18 of the screw compressor 10 are driven.

About the relief valve 80 is not shown in detail ensures that in the supply line 32 is not the high pressure prevailing in the operating state, for example, the output side of the screws 16, 18, can be locked, but that in particular at the start of the compressor in the supply line 32 always a low inlet pressure, in particular atmospheric pressure exists. Otherwise, with a start-up of the compressor, a very high pressure would initially arise on the output side of the screws 16 and 18, which would overload the drive motor.

Fig. 2 shows a schematic representation of an inventive

Screw compressor system 100 with the screw compressor 10 shown in Fig. 1 and a control and regulating unit 110th

The control and regulation unit 110 is here as part of the

Screw compressor system 100 is formed.

In principle, however, it can be provided that the control and regulation unit 1 10 part of an air treatment system of the commercial vehicle, part of a

Engine or vehicle control of the commercial vehicle or as a separate control and Regeiungseinheit 1 10 is formed. The control and regulating unit 10 is here designed and configured such that during operation of the screw compressor 10 it monitors the ratio of service life and switch-on time of the screw compressor drive for driving the screws 16 and 18 and adjusts this ratio to a predetermined range.

In this case, this range is selected such that there is a ratio of service life to switch-on time, in which the switch-on time is> 30%. In particular, an area is selected here that is between 30 to 50% on-time, so that the service life is between 50 to 70% and the switch-on time is about 30 to 50%.

With a switch-on time of approx. 30%, the service life is approx. 70%.

In order to be able to keep the ratio of service life to switch-on time also correspondingly constant, the control and regulation unit 110 is furthermore designed and configured such that it influences the rotational speed of the screw compressor drive.

It is ensured that by reducing or increasing the speed of the screw compressor drive over the entire operating time, the desired amount of compressed air is provided by the screw compressor 10, but the ratio of service life and turn-on is maintained.

In order to work economically and energy efficient, it will continue through the

Control and regulation unit 1 10 the speed always above one

Kept minimum speed.

This is based on the realization that below the minimum speed the specific energy consumption of the screw compressor drive (ie, the amount of energy needed to compress one cubic meter (m ³ ) of air) increases very much. In other words, it is thus avoided that excessive power loss or excessive losses occur. Through the constant holder! the ratio of service life to switch-on time is thus achieved overall that over the entire operating time of the screw compressor 10 can be kept relatively constant at an operating temperature. By holding the compressor at operating temperature throughout

Operating time is safely avoided _« that it is in the housing 20 of the

Screw compressor 10 can come to condensation.

Due to the constant operating temperature and the holding of the screw compressor 10 at the operating temperature, condensation in the housing 20 is reliably avoided.

Claims

1 .. screw compressor system (100) for a commercial vehicle with at least one screw compressor (10), at least one screw compressor drive and at least one control and / or regulating unit (110), wherein the control and / or regulating unit (1 10) with the screw compressor in Connection stands, wherein the control and / or regulating unit (1 10) is designed and configured _» that during operation of the screw compressor (10) monitors the ratio of service life and on time of the screw compressor drive and controls this ratio to a predetermined range and / or adjusts.

2. Screw compressor system (100) according to claim 1,

characterized in that

the control and / or regulating unit (1 10) part of the

Screw compressor system (10).

3. screw compressor system (100) according to claim 1,

characterized in that

the control and / or regulating unit (1 10) part of a

Air treatment system of the commercial vehicle,

4. screw compressor system (100) according to claim 1,

characterized in that

the control and / or regulating unit (1 10) part of a motor or

Vehicle control of the commercial vehicle is.

5. screw compressor system (100) according to claim 1,

characterized in that

the control and / or regulating unit (110) is a separate control and / or regulating unit (1 10).

6. Screw compressor system (100) according to one of the preceding claims, characterized in that the range is selected such that there is a ratio of service life to switch-on time in which the switch-on time is approximately 20-40%, in particular greater than 30%.

7, screw compressor system (100} according to any one of the preceding claims, characterized in that

the control and / or regulating unit (1 10) is designed and configured such that it influences the rotational speed of the screw compressor drive in such a way that the

Ratio of service life and on-time of the screw compressor drive is kept within the specified range.

8, screw compressor system (100) according to claim 7,

characterized in that

the control and / or regulating unit (1 10) is designed and configured such that it always has the rotational speed of the screw compressor drive above one

Minimum speed stops.