Supercharging structure for high-horsepower natural gas engine

Abstract

The utility model relates to the field of high-horsepower engines, in particular to a supercharging structure for a high-horsepower natural gas engine, which comprises a supercharger compressor, a supercharger intermediate and a supercharger volute. A diffuser and a compressor impeller are arranged in the supercharger compressor, an intermediate impeller is arranged in the supercharger intermediate, the compressor impeller is connected with the intermediate impeller through a driving shaft, the air entraining device is communicated with the diffuser, and the compressor impeller is connected with the intermediate impeller through a driving shaft. The problems that according to traditional high-pressure EGR at the present stage, air is entrained from the front portion of a turbine, waste gas is led out of a gas compressor and then mixed with fresh air to enter a cylinder to participate in combustion, due to the working characteristics of a turbocharger, the front pressure of the turbine is lower than the after-pressure pressure under the medium-low-rotating-speed and medium-high-load working conditions of an engine, and EGR needs to be achieved through auxiliary measures are solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of large horsepower engine, concretely relates to a supercharging structure for large horsepower natural gas engine. BACKGROUND

[0002] The standards of NOx emission in automobile exhaust in global emission regulations are continuously upgraded, and supercharger technology is an important way to achieve energy saving and emission reduction, exhaust gas recirculation (EGR) is one of the important ways to reduce NOx emission, high pressure EGR (HP-EGR) has also been widely commercially applied, but adopting high pressure EGR will increase the pumping loss of the engine, increase the fuel consumption rate of the engine, in order to meet the latest emission regulations, it is necessary to further improve the EGR rate, but the pressure difference between the front end of the turbine inlet (pre-turbine) and the rear end of the compressor outlet (post-compressor) in the supercharged engine cannot meet the demand of the EGR rate, and the engine EGR rate can only be improved through auxiliary measures, the traditional high pressure EGR is from the pre-turbine, the exhaust gas is introduced from the compressor, and then mixed with fresh air to enter the cylinder to participate in combustion, in addition, the working characteristics of the turbocharger cause the pre-turbine pressure to be lower than the post-compressor pressure in the medium and high load conditions of the engine at low and medium speeds, and auxiliary measures are needed to realize EGR.

[0003] At present, a supercharging mechanism for large horsepower natural gas engine is proposed to solve the above-mentioned problems. CONTENT OF THE UTILITY MODEL

[0004] The utility model aims at providing a supercharging structure for large horsepower natural gas engine to solve the problems that the traditional high pressure EGR is from the pre-turbine, the exhaust gas is introduced from the compressor, and then mixed with fresh air to enter the cylinder to participate in combustion, the working characteristics of the turbocharger cause the pre-turbine pressure to be lower than the post-compressor pressure in the medium and high load conditions of the engine at low and medium speeds, and auxiliary measures are needed to realize EGR.

[0005] To solve the above technical problems, the utility model adopts the following technical scheme:

[0006] A supercharging structure for large horsepower natural gas engine, comprising a supercharger compressor, a supercharger intermediate body and a supercharger volute, the supercharger compressor and the supercharger intermediate body are connected through the supercharger volute, an expander and a compressor impeller are arranged in the supercharger compressor, an intermediate body impeller is arranged in the supercharger intermediate body, the compressor impeller and the intermediate body impeller are connected through a drive shaft, and an air induction device is further arranged, the air induction device is in communication with the expander.

[0007] Further limited, the air induction device is annular tubular, spirally arranged around the air inlet of the supercharger compressor, and the outer wall of the air induction device is connected with the outer wall of the supercharger compressor.

[0008] Further limited, the air induction device is provided with air inlet and air outlet, the air outlet and the diffuser are communicated, the air inlet introduces the waste gas before the vortex into the diffuser through the air outlet.

[0009] The beneficial effect of the utility model relative to the present stage technology is:

[0010] The scheme of the utility model introduces the waste gas before the vortex into the diffusher, mixes with fresh air of the outlet of the compressor and then enters the cylinder, utilizes the low static pressure at the inlet of the diffuser of the compressor, improves the positive static pressure difference of the waste gas entering the engine intake system, improves the EGR rate and reduces the pumping loss of the engine. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is the front view schematic drawing of the utility model;

[0012] Figure 2 It is the front view schematic drawing of the supercharger compressor of the utility model;

[0013] Figure 3 It is Figure 2 The partial sectional view of B-B direction of;

[0014] Figure 4 It is the system structure principle drawing of the utility model.

[0015] Corresponding: 1-supercharger compressor, 2-supercharger intermediate body, 3-supercharger volute, 4-diffuser, 5-compressor impeller, 6-driving shaft, 7-air induction device, 8-air inlet in the drawing. DETAILED DESCRIPTION

[0016] In order to make the technical personnel in the field can better understand the technical scheme of the utility model, the utility model technical scheme is further explained below with the drawings and examples. EMBODIMENT

[0017] As Figures 1-4 Shown, a kind of for large horse power natural gas engine's supercharging structure, including supercharger compressor 1, supercharger intermediate body 2 and supercharger volute 3, supercharger compressor 1 and supercharger intermediate body 2 are connected by supercharger volute 3, and supercharger compressor 1 is provided with diffuser 4 and compressor impeller 5, and supercharger intermediate body 2 is provided with intermediate body impeller, and compressor impeller 5 and intermediate body impeller are connected by driving shaft 6, further include air induction device 7, air induction device 7 is annular tubular, and is spirally arranged around the air inlet 8 of supercharger compressor 1, and the outer wall of air induction device 7 is connected with the outer wall of supercharger compressor 1, air induction device 7 is provided with air inlet and air outlet, and the air outlet is communicated with diffuser 4, and the air inlet introduces the waste gas before the vortex into diffuser 4.

[0018] The turbocharger mainly utilizes exhaust gas to drive a turbine, which involves that exhaust gas discharged by an exhaust manifold pushes turbine blades to drive a coaxial compressor impeller 5, so as to compress intake air; the diffuser 4 in the technical solution is a vaneless diffuser; the compressor adds an air bleeding device 7 on the basis of keeping the parameters of the original compressor impeller, the diffuser 4 and the volute flow channel unchanged; the air outlet of the air bleeding device 7 is in communication with the diffuser 4, so that the air bleeding can smoothly enter the inside of the diffuser 4 of the compressor through the air bleeding device 7.

[0019] The traditional high-pressure EGR is from pre-turbine air bleeding; exhaust gas is mixed with fresh air after being led out from the compressor and then enters the cylinder to participate in combustion, while the technical solution of the application is to lead the pre-turbine exhaust gas into the diffuser and mix with fresh air at the outlet of the compressor before entering the cylinder, which fully utilizes the low static pressure at the inlet of the compressor diffuser, improves the positive static pressure difference for driving exhaust gas to enter the engine intake system, improves the EGR rate, reduces the pumping loss of the engine, and when designing the air bleeding device, the spiral of the air bleeding device is provided with a scroll air inlet section to make the air bleeding gas entering the diffuser have a higher tangential velocity, so as to reduce the energy loss of the air bleeding and the gas mixing at the outlet of the impeller; the air bleeding structure with scroll air inlet is adopted, the air bleeding gas entering the diffuser has a higher tangential velocity, which is called air bleeding with scroll air inlet; the efficiency and pressure ratio of the air bleeding compressor with scroll air inlet are higher than the corresponding values of the air bleeding compressor without scroll air inlet; the total pressure loss coefficient of the diffuser of the air bleeding compressor with scroll air inlet is smaller than the corresponding value of the air bleeding compressor without scroll air inlet; the scroll air inlet can effectively reduce the tangential velocity difference between the outlet of the air bleeding structure and the outlet of the compressor impeller, reduce the flow loss and mixing loss caused by the air bleeding entering the diffuser, and improve the adiabatic efficiency of the air bleeding compressor.

[0020] In the description of the utility model, it is understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, therefore it cannot be understood as a limitation on the utility model.

[0021] The above describes in detail the supercharging structure for the large-horsepower natural gas engine, and the description of the specific embodiment is only used to help understand the method and core idea of the utility model, and it should be pointed out that, for ordinary skilled persons in the technical field, without departing from the utility model, the utility model can be improved and modified in many ways, and these improvements and modifications also fall within the protection scope of the utility model claims.

Claims

1. A supercharging structure for a high-power natural gas engine, comprising a supercharger compressor (1), a supercharger interbody (2) and a supercharger volute (3), said supercharger compressor (1) and said supercharger interbody (2) being connected by said supercharger volute (3), said supercharger compressor (1) being provided with a diffuser (4) and a compressor impeller (5), said supercharger interbody (2) being provided with an interbody impeller, said compressor impeller (5) and said interbody impeller being connected by a drive shaft (6), characterized in that: Further comprising a bleed air device (7) which is communicated with the diffuser (4).

2. A supercharging structure for a large horsepower natural gas engine according to claim 1, characterized by: The bleed air device (7) is annular tubular, spirally arranged around the air inlet (8) of the supercharger compressor (1) and the outer wall of the bleed air device (7) is connected with the outer wall of the supercharger compressor (1).

3. A supercharging structure for a large horsepower natural gas engine according to claim 1, characterized by: The bleed air device (7) is provided with an air inlet and an air outlet, the air outlet is communicated with the diffuser (4), and the air inlet introduces the pre-vortex exhaust gas into the diffuser (4) through the air outlet.

4. A supercharging arrangement for a heavy duty natural gas engine according to claim 1, characterized in that: The diffuser (4) is a vaneless diffuser.

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