A supercharging device suitable for low-pressure EGR system and low-pressure EGR system

Abstract

The present invention provides a supercharging device suitable for a low-pressure EGR system, wherein the supercharging device is connected to an intake system with EGR, wherein the intake system is used to transmit a mixed gas formed by mixing EGR exhaust gas cooled by an EGR cooler and fresh air to the supercharging device, wherein the supercharging device includes a compressor and a separation device provided at the air inlet of the compressor, and after liquid water is separated from the mixed gas by the separation device, the remaining dry mixed gas continues to flow into the compressor for supercharging. The present invention can protect the compressor impeller from the impact and corrosion of liquid water, and effectively solve the problem that the supercharger cannot be started due to freezing of liquid water in high-cold areas, thereby expanding the scope of use of the low-pressure EGR technology to high-cold areas. The present invention also relates to a low-pressure EGR system.

Description

Technical Field

[0001] The present invention relates to the field of engine technology, and in particular to a supercharging device and a supercharging method suitable for a low-pressure EGR system. Background Art

[0002] Using EGR (Exhaust Gas Recirculation) technology can effectively reduce NO x Emissions, while effectively reducing engine fuel consumption, is one of the current mainstream technologies for energy conservation and emission reduction. EGR engines with a supercharging system are mainly divided into two types: high-pressure EGR technology and low-pressure EGR technology. Compared with high-pressure EGR technology, low-pressure EGR can be used in a wider range of test conditions, but because low-pressure EGR needs to be mixed with fresh air after cooling and then enters the compressor for supercharging, the EGR exhaust gas undergoes secondary cooling, and liquid water precipitates and continuously hits the compressor blades. The corrosive substances in the EGR exhaust gas also put forward new requirements for the compressor's anti-corrosion ability; and in cold areas, the presence of liquid water causes the compressor to freeze, making the application of low-pressure EGR technology in high-cold areas difficult.

[0003] In the existing first technical solution: the low-pressure EGR function is turned off in high-altitude and cold areas, which limits the scope of use of the low-pressure EGR technology and makes it impossible to fully demonstrate the technical advantages.

[0004] In the existing second technical solution: through the reasonable arrangement of the whole machine, the supercharger is placed at a high position, and the EGR cooler is arranged at an angle, so that the liquid water generated after the EGR exhaust gas is cooled by the EGR cooler can flow back, and a drain valve is set at the lowest point of the pipeline to release it. However, due to the limitation of the overall layout, it is usually difficult to place the supercharger at a high position, and the EGR pipeline needs to be designed with an extremely low point for draining, which will lengthen the pipeline and cause a decrease in the transient response performance of the engine. Summary of the invention

[0005] In view of this, it is necessary to provide a boosting device suitable for a low-pressure EGR system that is not restricted by the overall machine layout and does not require special anti-corrosion treatment of the compressor.

[0006] The present invention provides a supercharging device suitable for a low-pressure EGR system, wherein the supercharging device is connected to an intake system with EGR, and the intake system is used to transmit a mixed gas formed by mixing EGR exhaust gas cooled by an EGR cooler and fresh air to the supercharging device. The supercharging device includes a compressor and a separation device arranged at the air inlet of the compressor. After the mixed gas passes through the separation device to separate liquid water, it flows into the interior of the compressor for supercharging.

[0007] In a preferred embodiment, the separation device includes a hydrophilic molecular sieve structure and a collecting chamber arranged outside the hydrophilic molecular sieve structure, and the collecting chamber is used to collect the liquid water separated by the hydrophilic molecular sieve structure.

[0008] In a preferred embodiment, a mounting portion for mounting and accommodating the hydrophilic molecular sieve structure is provided at the air inlet of the compressor, the mounting portion is hollow, and the collecting chamber is the space formed between the hydrophilic molecular sieve structure and the inner wall of the mounting portion.

[0009] In a preferred embodiment, the mounting portion is an air inlet end of the compressor, or the mounting portion is a connecting piece arranged on the outside of the air inlet end of the compressor.

[0010] In a preferred embodiment, the separation device further comprises a drain pipe connected to a water outlet of the collecting chamber, the water outlet of the collecting chamber is located below the hydrophilic molecular sieve structure, and the water outlet of the drain pipe extends outward to the outside of the compressor.

[0011] In a preferred embodiment, the hydrophilic molecular sieve structure is a helical structure.

[0012] In a preferred embodiment, the hydrophilic molecular sieve structure is formed by adhering a hydrophilic molecular sieve membrane to a spiral support.

[0013] In a preferred embodiment, the boosting device is an engine boosting system, which includes but is not limited to a turbocharger, a mechanical supercharger and an electronic supercharger, and the turbocharger has a turbine and a compressor that are coaxially driven, and the turbine is located between the engine exhaust duct outlet and the catalyst inlet; while the mechanical supercharger and the electronic supercharger only contain a compressor.

[0014] The present invention also relates to a low-pressure EGR system, comprising the above-mentioned supercharging device suitable for the low-pressure EGR system, an air pipeline for transmitting fresh air, and an EGR pipeline for transmitting low-pressure EGR exhaust gas. The exhaust gas after passing through the engine catalyst flows into the EGR cooler through the EGR pipeline and is cooled to form EGR exhaust gas. The EGR exhaust gas is mixed with the fresh air in the air pipeline and then enters the compressor of the supercharging device for supercharging.

[0015] In summary, the present invention adds a separation device at the air inlet of the compressor in the supercharging device, so that the liquid water contained in the mixture of the cooled low-pressure EGR and fresh air can be filtered, collected and discharged out of the supercharging device through the separation device, so as to protect the compressor impeller from the impact and corrosion of liquid water, and effectively solve the problem that the supercharger cannot be started due to the freezing of liquid water in high-altitude cold areas, and expand the scope of use of low-pressure EGR technology to high-altitude cold areas; the present invention has no special requirements for the overall layout of the engine, the EGR pipeline can be shortened as much as possible, and the transient response performance of the engine is improved.

[0016] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following specifically cites a preferred embodiment and describes it in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure shows a schematic diagram of a specific embodiment of a supercharging device applicable to a low-pressure EGR system provided by the present invention;

[0018] Figure 2 The cross-sectional view of a specific embodiment of a supercharging device suitable for a low-pressure EGR system provided by the present invention is shown. DETAILED DESCRIPTION

[0019] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the present invention is described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0020] like Figure 1 As shown, the present invention provides a supercharging device suitable for a low-pressure EGR system. The supercharging device 10 is connected to the outlet of an intake system pipeline with EGR, so as to transmit a mixed gas formed by mixing EGR exhaust gas cooled by an EGR cooler and fresh air to the supercharging device 10.

[0021] like Figure 2 As shown, the supercharging device 10 includes a compressor 11 connected to the outlet of the intake system pipeline and a separation device 12 arranged at the intake port of the compressor 11. The supercharging device 10 provided by the present invention has no special requirements for the overall layout of the engine, is not restricted by the overall layout, and does not need to re-arrange the pipeline so as to set a drain valve at an extremely low point to drain water, so it can effectively shorten the length of the EGR pipeline and improve the transient response performance.

[0022] Since the separation device 12 is built into the supercharging device 10, other parts of the supercharging device 10 provided by the present invention do not need to be modified, which can protect the compressor impeller from the impact and corrosion of liquid water, and effectively solve the problem of the supercharger being unable to start due to liquid water freezing in high-altitude cold areas, thereby expanding the scope of use of low-pressure EGR technology to high-altitude cold areas.

[0023] In a preferred embodiment of the present invention, the supercharging device 10 is applicable to all engine supercharging systems with a compressor 11, including but not limited to a turbocharger, a mechanical supercharger and an electronic supercharger, and the turbine 17 of the turbocharger and the compressor 11 are coaxially driven, and the turbine 17 is located between the engine exhaust duct outlet and the catalyst inlet; while the mechanical supercharger and the electronic supercharger only contain a compressor, that is, even if the compressor 11 is Figure 1The turbine 17 in the embodiment is removed without affecting the function of the supercharging device (with the compressor 11) and the EGR system (with emphasis on Figure 1 ).

[0024] Specifically, the separation device 12 is arranged at the inlet of the compressor 11 in the supercharging device 10, so that the mixed gas input through the intake system first enters the separation device 12, and the dry mixed gas formed after the liquid water is separated by the separation device 12 continues to flow into the compressor 11 for supercharging. The present invention improves the compressor 11 and is applicable to all supercharging devices 10 with the improved compressor 11, so that before the mixed gas is supercharged, the liquid water in the mixed gas of the cooled EGR exhaust gas and the fresh air is effectively filtered, thereby avoiding the impact and corrosion of the compressor 11 in the supercharging device 10 by the liquid water, and effectively solving the problem that the supercharger cannot be started due to the easy freezing of liquid water in high-altitude cold areas, thereby expanding the application scope of low-pressure EGR technology in high-altitude cold areas, and no special anti-corrosion treatment is required for the compressor.

[0025] That is, the present invention designs a boosting device 10 with a novel compressor 11, which is suitable for all engine boosting systems with compressors (including but not limited to turbochargers, mechanical superchargers and electronic superchargers), so as to be applied to the engine operating conditions of the low-pressure EGR system; and the present invention can be applied to all engine operating conditions, and there is no situation of liquid water precipitation. The present invention can still be used as an ordinary boosting device 10 to boost the intake air.

[0026] Specifically, the separation device 12 arranged at the entrance of the supercharger compressor 11 includes a hydrophilic molecular sieve structure 14 and a collecting chamber 15. The hydrophilic molecular sieve structure 14 is a spiral structure, and the collecting chamber 15 is used to collect liquid water separated by the hydrophilic molecular sieve structure 14. The present invention arranges a hydrophilic molecular sieve structure 14 at the entrance of the compressor 11 of the supercharging device 10, which can increase the contact area with the intake air and thus improve the efficiency of filtering liquid water. The mixed gas obtained by mixing the cooled low-pressure EGR exhaust gas and the fresh air enters the hydrophilic molecular sieve structure 14 to separate the liquid water in the mixed gas and discharge it through the collecting chamber 15. The dry mixed gas obtained after filtration enters the interior of the compressor 11 and is pressurized by the compressor impeller. At this time, the compressor blades are protected from the impact and erosion of water droplets, and the compressor no longer needs to be subjected to special anti-corrosion treatment, thereby improving the service life of the supercharging device 10.

[0027] In a preferred embodiment provided by the present invention, the hydrophilic molecular sieve structure 14 is formed by adhering a hydrophilic molecular sieve membrane to a spiral support, thereby ensuring that liquid water molecules can be filtered efficiently.

[0028] In detail, Figure 2As shown, in the present invention, the air inlet of the compressor 11 includes a mounting portion 13 for mounting and accommodating a hydrophilic molecular sieve structure 14, wherein the mounting portion 13 is hollow, and the collecting chamber 15 is a space formed between the hydrophilic molecular sieve structure 14 and the inner wall of the hollow portion of the mounting portion 13, so as to facilitate the hydrophilic molecular sieve structure 14 to separate and collect the liquid water in the mixed gas.

[0029] In a specific embodiment provided by the present invention, the mounting portion 13 is the air inlet end of the compressor 11, and correspondingly, the collecting chamber 15 is the space formed between the hydrophilic molecular sieve structure 14 and the inner wall of the air inlet of the compressor 11 (the inner wall of the mounting portion 13).

[0030] In another specific embodiment provided by the present invention, the mounting portion 13 is also a connector provided on the outside of the air inlet end of the compressor 11, wherein the mounting portion 13 is hollow, and correspondingly, the collecting chamber 15 is a space formed between the hydrophilic molecular sieve structure 14 and the inner wall of the hollow portion of the mounting portion 13; further, the mounting portion 13 is preferably a metal connector. For the method of seamlessly connecting the mounting portion 13 with the air inlet of the compressor 11, specific reference may be made to the prior art, and the specific details will not be repeated here.

[0031] Furthermore, the separation device 12 also includes a drain pipe 16 connected to the water outlet of the collecting chamber 15 for discharging the separated liquid water. The water inlet of the drain pipe 16 is connected to the water outlet of the collecting chamber 15, and the water outlet of the collecting chamber 15 is located below the hydrophilic molecular sieve structure 14, so that the collecting chamber 15 can collect and discharge the liquid water in the mixed gas.

[0032] Furthermore, the water outlet of the drain pipe 16 extends outward to the outside of the compressor 11, so that the liquid water in the mixed gas is collected and stored in the collecting chamber 15, and when the liquid water is stored in the collecting chamber 15 to a certain amount, the liquid water is promptly drained out of the compressor 11 through the drain pipe 16, which can effectively avoid the impact and corrosion of the compressor 11 by liquid water, and there is no need for special anti-corrosion treatment of the compressor 11, thereby expanding the scope of use of low-pressure EGR technology in high-cold areas.

[0033] The present invention also relates to a low-pressure EGR system, which includes the above-mentioned supercharging device suitable for the low-pressure EGR system, an air pipeline for transmitting fresh air, and an EGR pipeline for transmitting low-pressure EGR exhaust gas. The exhaust gas after the engine catalyst flows into the EGR cooler from the EGR pipeline to form EGR exhaust gas after cooling, and then mixes with the fresh air in the air pipeline, and then enters the compressor 11 of the supercharging device 10 for supercharging (with emphasis on Figure 1 ).

[0034] For other related contents and technical features of other relevant components, low-pressure EGR system and engine, please refer to the existing technology, and the details will not be repeated here.

[0035] In summary, the present invention adds a separation device at the air inlet of the compressor in the supercharging device, so that the liquid water in the cooled low-pressure EGR and fresh air mixture is filtered, collected and discharged out of the supercharging device through the hydrophilic molecular sieve structure in the separation device, so as to protect the compressor impeller from the impact and corrosion of liquid water, and effectively solve the problem that the supercharger cannot be started due to the freezing of liquid water in high-altitude cold areas, and expand the scope of use of low-pressure EGR technology to high-altitude cold areas; and the supercharging device itself does not need to be specially anti-corrosion treated; the present invention has no special requirements for the overall layout of the engine, and the EGR pipeline can be shortened as much as possible, thereby improving the transient response performance of the engine.

[0036] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A supercharging device suitable for a low-pressure EGR system, the supercharging device (10) being connected to an intake system with EGR, the intake system being used to transmit a mixed gas formed by mixing EGR exhaust gas cooled by an EGR cooler and fresh air to the supercharging device (10), characterized in that: The boosting device (10) comprises a compressor (11) connected to the outlet of the air intake system and a separation device (12) arranged at the air intake of the compressor (11); after the mixed gas passes through the separation device (12) to separate liquid water, the mixed gas flows into the interior of the compressor (11) for boosting; the separation device (12) comprises a hydrophilic molecular sieve structure (14) and a collection chamber (15) arranged outside the hydrophilic molecular sieve structure (14); the collection chamber (15) is used to collect liquid water that has passed through the hydrophilic molecular sieve structure (14). The sub-sieve structure (14) separates liquid water; the compressor (11) is provided with a mounting portion (13) at the air inlet for mounting and accommodating the hydrophilic molecular sieve structure (14); the mounting portion (13) is hollow; the collecting chamber (15) is a space formed between the hydrophilic molecular sieve structure (14) and the inner wall of the mounting portion (13); the hydrophilic molecular sieve structure (14) is a spiral structure, and the hydrophilic molecular sieve structure (14) is formed by adhering a hydrophilic molecular sieve membrane to a spiral support.

2. The supercharging device suitable for a low-pressure EGR system according to claim 1, characterized in that: The mounting portion (13) is an air inlet end portion of the compressor (11), or the mounting portion (13) is a connecting piece arranged outside the air inlet end portion of the compressor (11).

3. The supercharging device suitable for a low-pressure EGR system according to claim 1, characterized in that: The separation device (12) further comprises a drainage pipe (16) connected to a water outlet of the collection chamber (15), the water outlet of the collection chamber (15) being located below the hydrophilic molecular sieve structure (14), and the water outlet of the drainage pipe (16) extending outwardly to the outside of the compressor (11).

4. The supercharging device suitable for a low-pressure EGR system according to claim 1, characterized in that: The supercharging device (10) is an engine supercharging system, and the supercharging device (10) comprises a turbocharger, a mechanical supercharger and an electronic supercharger.

5. A low-pressure EGR system, comprising an air pipeline for transmitting fresh air and an EGR pipeline for transmitting low-pressure EGR exhaust gas, characterized in that: It also includes a supercharging device (10) suitable for a low-pressure EGR system as described in any one of claims 1 to 4, wherein the exhaust gas after passing through the engine catalyst flows into the EGR cooler through the EGR pipeline to form EGR exhaust gas after being cooled, and then mixed with the fresh air in the air pipeline and enters the compressor (11) of the supercharging device (10) for supercharging.

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