This application is a U.S. National Stage application of PCT/EP2018/077933, filed Oct. 12, 2018, and published on Apr. 16, 2020, as WO 2020/074103 A1, all of which is hereby incorporated by reference in its entirety.
The present invention concerns a compressed air generation system for an automotive vehicle, and an automotive vehicle, such as a truck, comprising such a compressed air generation system.
Automotive vehicles, such as trucks, are equipped with air compressors for feeding some auxiliary systems, such as braking systems, with compressed air. To increase the air delivery and reduce the power consumption of the air compressors, it is known to feed the air compressor with compressed air produced by a turbocompressor of the vehicle. This allows operating the air compressor at a lower compression rate. Such technique is for instance described in DE 19637571, in which compressed air is delivered to the air compressor from the turbocompressor if enough compressed air is available.
Air compressors are designed to work in a predetermined air pressure range. The compressed air delivered by the turbocompressor may have pressure peaks depending on the operation conditions of the internal combustion engine of the vehicle. If the air compressor is fed with air pressures that are above the maximal pressure value of the pressure range, the air compressor may be damaged.
To withstand pressure peaks, the compression ratio of the air compressor should be reduced, and internal component be reinforced to accept addition constraint. If the turbocompressor does not deliver enough pressured air (for example when the engine is idle) to the air compressor with reduces compression ratio, the compression efficiency may be low, leading to increased filling time of the air tanks and fuel overconsumption.
The aim of the invention is to provide a compressed air generation system in which the operation of the air compressor is optimized to withstand overpressure peaks in the compressed air delivered by the turbocompressor and avoid power overconsumption.
To this end, the invention concerns a compressed air generation system for an automotive vehicle, comprising:
This compressed air generation system is characterized in that it comprises a pressure regulator placed downstream the turbocompressor and upstream the air compressor and which limits the pressure of the compressed air fed from the turbocompressor to the air compressor to a first threshold.
Thanks to the invention, the pressure peaks from the turbocompressor are cut below a predetermined threshold depending on the pressure range of the air compressor, avoiding damage on the air compressor.
According to other aspects of the invention which are advantageous but not compulsory, such a flow pressure regulator may incorporate one or several of the following features:
The invention also concerns an automotive vehicle comprising a compressed air generation system as mentioned here-above.
The invention will now be explained in reference to the annexed drawings, as an illustrative example. In the annexed drawings:
An automotive vehicle V, such as a truck, represented on
The vehicle V comprises an air compressor 8. For example, the air compressor 8 can be a piston compressor.
The air compressor 8 is adapted to feed a compressed air tank 10 in which compressed air is stored in order to feed one or several pneumatically driven sub-systems of the vehicle V, such as a non-shown braking system.
The air compressor 8 is adapted to compress air provided by the turbocompressor 4. The air compressor 8 is fed by an inlet pipe 80 which originates from the air intake pipe 44. Compressed air is fed to the tank 10 via an outlet pipe 82 of the air compressor 8.
The air compressor 8, the turbocompressor 4 and the air tank 10 form together a compressed air generation system 12.
The compressed air generation system 12 comprises a pressure regulator 14 connected upstream the air compressor 8 and which limits the pressure P4 of the compressed air fed from the turbocompressor 4 to the air compressor 8. As represented on
The pressure regulator 14 is represented on
The piston 24 comprises a collar 240 adapted to make contact with a valve seat 160 of the valve body 16 to close passage of air from the intake port 18 towards the outlet port 20. Non-shown sealing gaskets may be provided on the collar 240 to tighten contact with the seat 160.
When the pressure regulator 14 is open (
Depending on the air pressure, equal to the pressure P4, in the intake port 18, which communicates with the chamber 22 via the outlet port 20 and the hole 162, the piston 24 is driven downwards along arrow A3, resulting in the collar 240 getting closer to the seat 160 and limiting the air pressure that flows into the outlet port 20, equal to the intake pressure P8 of the air compressor 8.
The compressed air generation system 12 comprises a tank sensor 30 adapted to detect the quantity of compressed air contained in the air tank 10, and a controlled valve adapted to close the feeding of the inlet pipe 80 of the air compressor 8 with the turbocompressor 4 if the tank sensor 30 detects that the air tank 10 is full. The tank sensor 30 may be a pressure sensor adapted to measure the air pressure P10 in the tank 10. During filling of the air tank 10, the air pressure P10 of the air tank 10 progressively increases up to a maximal pressure Pmax.
The controlled valve is formed by the pressure regulator 14 that can be closed. The pressure regulator 14 comprises a controllable actuator adapted to close the pressure regulator 14 whatever the respective pressures P4 and P8 in the inlet port 18 and the outlet port 20.
The controllable actuator is a pressure-controlled piston 32 which closes the pressure regulator 14 by acting to move the piston 24 towards a closed position shown on
In the absence of control pressure acting on the pressure controlled piston 32, the pressure controlled piston 32 is urged upwards, towards its position of
The closing of the pressure regulator 14 if the air tank 10 is full avoids operation of the air compressor 8 while air compression is not useful. The closing of compressed air feeding of the air compressor 8 from the turbocompressor 4 avoids operation of the air compressor 8 while it is not desired. From the closing of the pressure regulator, the pressure P10 remains steady at value Pmax.
The compressed air generation system 12 may comprise a control unit 34 able to receive signals from the tank sensor 30, and to control the pressure regulator 14 via a pneumatic control pipe 36 connected to the hole 164a. The control unit 34 may include electronic and/or pneumatic components.
In order to guarantee that the air compressor 8 does not operate while the air tank 10 is full, the air compressor 8 is able to be stopped or placed in a rest mode when the tank sensor 30 detects that the air tank 10 is full. This control of the air compressor 8 may be operated with the control unit 34 via an electric signal. The control unit 34 may also be able to control any other working parameter of the air compressor 8.
According to an embodiment, the controlled valve may be distinct from the pressure regulator 14 and be formed by a valve 11, for example a three-way valve, connected on the first section 80a of the inlet pipe 80, upstream the pressure regulator 14. The valve 11 may be controlled by the control unit 34.
The pressure regulator 14 comprises a pressure relief valve adapted to release to the atmosphere compressed air accumulated between the pressure regulator 14 and the air compressor 8, in other words, in the second section 80b of the inlet pipe 80.
For example, as represented on
When the air tank 10 is full, the piston 24 is moved towards the closed position of the pressure regulator 14, as shown on
Compressed air flowing in the central channel 244 flows in the chamber 22, which comprises air vents 220 allowing release of the air contained in the chamber 22 to the atmosphere, as shown by arrows A6. The portion of the chamber 22 located on the side of the active surface 242 is sealed from the atmosphere by a sealing gasket 222.
A second embodiment of the invention is represented on
In the pressure regulator of
The piston 50 comprises a rod 54 which is partially inserted into an auxiliary chamber 56 located inside the lower side 224 of the chamber 22. In the auxiliary chamber 56, the piston 50 is terminated by a head 58, comprising a sealing gasket 60. Another sealing gasket 62 is provided around the rod 54 to tighten the auxiliary chamber 56.
The pressure regulator 14 comprises a duct 64 which provides fluid communication between the auxiliary chamber 56 and the outside of the pressure regulator 14, allowing a control pressure to be exerted in the auxiliary chamber 56.
In the embodiment of
The working principle of the pressure regulator 14 is described on
On
In this configuration, the peripheral wall 248 has been moved closer to the bottom wall 226, but the piston 24 is still free to move downwards.
On
The travel of the piston 24 from its position of
The pressure control of the piston 50 may also be controlled via the control unit 34.
The intake pressure P8 therefore remains steady at the value T2. This pressure relief valve allows reducing the pressure between the pressure regulator 14 and the air compressor 8, to avoid creation by the air compressor 8 a resisting couple on the crankshaft of the engine 2.
According to a variant represented on
According to an embodiment, the pressure relief valve may be distinct from the pressure regulator 14, and formed by a valve 7 connected on the second section 80b, for example a three-way valve.
According to an optional embodiment, the vehicle V may comprise an exhaust after-treatment system (EATS) 9 provided on the exhaust line 6 and adapted to reduce particulates in the exhaust gases. To operate properly, the EATS 9 must be cleaned from times to times by warming up at a temperature around 450° C. To obtain this temperature, the exhaust gases can be warmed up by reducing the quantity of fresh air provided by the turbocompressor 4 in the air intake pipe 44. This can be done by opening the pressure regulator 14 at a time when it is closed so that compressed air delivered by the turbocompressor 4 will not be delivered to the engine 2, provoking an increase of the exhaust gases temperature. The compressed air tanks generally have a pressure varying between a cut-in threshold and a cut-off threshold (corresponding to the maximal pressure Pmax), which can be for example 11 bar and 12 bar. These thresholds can be changed during operation of the air tank 10, for example increased by 0.5 bar during an operation period when energy is free because the vehicle V is braking. By setting the cut-in and cut-off thresholds to higher values, the air compressor 8 becomes able to compress more air in the air tank 10, and compressed air is therefore drawn from the air intake pipe 44. This reduces the quantity of fresh air in the intake side of the engine 2, thereby increasing the temperature of the exhaust gases and reducing the warming time of the EATS 9.
The compressed air generation system 12 may also comprise a discharge valve 17, connected on the outlet pipe 82, and allowing evacuating air pressure downstream the air compressor 8 to avoid an overpressure in the air tank 10. This may avoid having to act on the operating parameters of the air tank 10. The discharge valve 17 may be controlled by the control unit 34.
The forced opening of the pressure regulator may be obtained by cutting the pressure control of the piston 32 commanded by the control unit 34. The setting of the pressure thresholds of the air tank 10 may be operated by an electric signal emitted by the control unit 34 towards the air tank 10.
The technical features of the embodiments and variants described above may be combined to form new embodiments of the invention.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2018/077933 | 10/12/2018 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2020/074103 | 4/16/2020 | WO | A |
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20210332744 | Moine | Oct 2021 | A1 |
Number | Date | Country |
---|---|---|
19637571 | Mar 1998 | DE |
2651735 | Oct 2013 | EP |
S59117864 | Aug 1984 | JP |
Entry |
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International Search Report and Written Opinion dated May 13, 2019 in corresponding International PCT Application No. PCT/EP2018/077933, 10 pages. |
European Communication pursuant to Article 94(3) EPC dated Mar. 31, 2023 in corresponding European Patent Application No. 18789045.4, 5 pages. |
Number | Date | Country | |
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20210332744 A1 | Oct 2021 | US |