A structure for increasing negative pressure

Abstract

The present invention discloses a structure for increasing negative pressure, which relates to an engine and solves the technical problem that the existing crankcase pressure cannot be stably less than the atmospheric pressure. The present invention includes a closed cycle crankcase, a supercharger, and an oil-gas separation mechanism. The ventilation pipe of the crankcase is connected to the air intake duct at the front end of the compressor through the oil-gas separation mechanism. The ventilation pipe is located between the anti-surge valve pipe and the compressor. The spacing between the ventilation pipe and the compressor is smaller than the spacing between the ventilation pipe and the anti-surge valve pipe. One end of the ventilation pipe extends obliquely toward the compressor or is provided with a first oblique cut facing the compressor. The present invention can reduce the influence of the anti-surge pipe airflow on the ventilation pipe by setting the spacing between the ventilation pipe and the compressor to be smaller than the spacing between the ventilation pipe and the anti-surge valve pipe, and setting one end of the ventilation pipe to extend obliquely toward the compressor or be provided with a first oblique cut facing the compressor, thereby increasing the suction force of the compressor on the air in the crankcase and ensuring that the crankcase pressure is stably less than the atmospheric pressure.

Description

Technical Field

[0001] The present invention relates to an engine, and more particularly to a structure for increasing negative pressure. Background Art

[0002] The "GB 17691-2018 Heavy-Duty Vehicle National VI Emission Standard" has the following requirements for the crankcase ventilation system: "C.5.11 For crankcase emission measurements of spark-ignition engines, the crankcase pressure should be measured at an appropriate position during the entire test training process. The pressure measurement accuracy should be within ±1kPa, and the crankcase pressure should not be greater than atmospheric pressure", that is, the crankcase pressure of the gas engine needs to be maintained at a negative pressure. Existing conventional crankcase ventilation systems include: open circulation systems, centrifugal oil-gas separators, and closed circulation systems. The open circulation system is directly connected to the atmosphere and cannot form negative pressure. Conventional centrifugal oil-gas separators have low centrifugal force, generate insufficient suction, and have low negative pressure, and cannot guarantee that the crankcase pressure is not greater than atmospheric pressure under any operating conditions. The supercharger anti-surge valve pipe A of the existing closed circulation system merges with the crankcase ventilation pipe B in advance (such as Figure 1 as shown) or the gap is too close (as shown Figure 2 As shown in the figure, when the anti-surge valve of the supercharger is working, it will release air, which will interfere with the air flow in the crankcase ventilation pipe B, causing the crankcase pressure to be greater than the atmospheric pressure, which does not meet the requirements. Therefore, increasing the negative pressure of the crankcase ventilation of the gas engine has become an important issue. Summary of the invention

[0003] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art. The purpose of the present invention is to provide a structure for increasing negative pressure that can ensure that the crankcase pressure is stably less than the atmospheric pressure.

[0004] The technical solution of the present invention is: a structure for increasing negative pressure, including a closed-cycle crankcase, a supercharger, and an oil-gas separation mechanism, wherein the ventilation pipe of the closed-cycle crankcase is connected to the air inlet at the front end of the compressor of the supercharger through the oil-gas separation mechanism, the ventilation pipe is located between the anti-surge valve pipe of the supercharger and the compressor, the spacing between the ventilation pipe and the compressor is smaller than the spacing between the ventilation pipe and the anti-surge valve pipe, and one end of the ventilation pipe connected to the air inlet extends obliquely toward the compressor or is provided with a first oblique cut facing the compressor.

[0005] As a further improvement, one end of the anti-surge valve pipe connected to the air inlet duct extends obliquely in a direction away from the compressor or is provided with a second oblique cut facing away from the compressor.

[0006] Furthermore, the angle between the anti-surge valve pipe and the intake duct is 30° to 90°.

[0007] Furthermore, the distance between the ventilation pipe and the anti-surge valve pipe is greater than 200 mm.

[0008] Furthermore, the oil-gas separation mechanism is an oil-gas separator of model H100-140.

[0009] Furthermore, the oil-gas separation mechanism is an air-driven oil-gas separator, and the compressed air inlet end of the air-driven oil-gas separator is connected to the automobile gas tank or the air inlet duct at the rear end of the compressor through an air pipe.

[0010] Furthermore, the oil-gas separation mechanism is an oil-driven oil-gas separator, and the oil inlet end of the oil-driven oil-gas separator is connected to the high-pressure main oil channel of the engine.

[0011] Beneficial Effects

[0012] Compared with the prior art, the present invention has the following advantages: by setting the distance between the ventilation pipe and the compressor to be smaller than the distance between the ventilation pipe and the anti-surge valve pipe, and setting one end of the ventilation pipe to extend obliquely toward the compressor or providing a first oblique cut facing the compressor, the present invention can reduce the influence of the airflow of the anti-surge pipe on the ventilation pipe, increase the suction force of the compressor on the air in the crankcase, and effectively ensure that the pressure in the crankcase is stably lower than the atmospheric pressure, ensuring that the requirement of "GB 17691-2018 Heavy-Duty Vehicle National VI Emission Standard" that the crankcase pressure is not greater than the atmospheric pressure is met. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the anti-surge valve pipe and the ventilation pipe merging in advance in the traditional technology;

[0014] Figure 2 It is a schematic diagram showing that the gap between the anti-surge valve pipe and the ventilation pipe in the conventional technology is too close;

[0015] Figure 3 It is a structural schematic diagram of the connection between the ventilation pipe and the compressor in the present invention;

[0016] Figure 4 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0017] Figure 5 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0018] Figure 6 This is a schematic diagram of the structure of Example 3 of the present invention.

[0019] Among them: 1-closed cycle crankcase, 2-supercharger, 3-oil-gas separation mechanism, 4-ventilation pipe, 5-compressor, 6-intake duct, 7-anti-surge valve pipe, 8-first oblique cut, 9-air pipe, 10-return oil pipe. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the specific embodiments in the accompanying drawings.

[0021] See also Figure 3-6 A structure for increasing negative pressure includes a closed-cycle crankcase 1, a supercharger 2, and an oil-gas separation mechanism 3. A ventilation pipe 4 of the closed-cycle crankcase 1 is connected to an air inlet 6 at the front end of a compressor 5 of the supercharger 2 through the oil-gas separation mechanism 3. The ventilation pipe 4 is located between an anti-surge valve pipe 7 of the supercharger 2 and the compressor 5. A spacing L1 between the ventilation pipe 4 and the compressor 5 is smaller than a spacing L between the ventilation pipe 4 and the anti-surge valve pipe 7. One end of the ventilation pipe 4 connected to the air inlet 6 extends obliquely toward the compressor 5 or is provided with a first oblique cut 8 facing the compressor 5, which can increase the suction force of the compressor 5 on the air in the closed-cycle crankcase 1, that is, increase the negative pressure. L1 can be minimized to increase the suction force, and L can be maximized to reduce the influence of the anti-surge valve pipe 7.

[0022] Furthermore, one end of the anti-surge valve pipe 7 connected to the air inlet 6 is extended obliquely in the direction away from the compressor 5 or is provided with a second oblique cut facing away from the compressor 5, which can effectively reduce the impact of the airflow of the anti-surge valve pipe 7 on the ventilation pipe 4 and improve the stability of the negative pressure in the closed cycle crankcase 1. Preferably, the angle α between the anti-surge valve pipe 7 and the air inlet 6 is 30° to 90°, and the spacing between the ventilation pipe 4 and the anti-surge valve pipe 7 is greater than 200 mm.

[0023] Example 1

[0024] The oil-gas separation mechanism 3 is an oil-gas separator of model H100-140, which has a simple structure and is easy to install.

[0025] Example 2

[0026] The oil-gas separation mechanism 3 is an air-driven oil-gas separator. The compressed air inlet end of the air-driven oil-gas separator is connected to the automobile gas tank or the air inlet 6 at the rear end of the compressor 5 through an air pipe 9. The oil outlet end of the air-driven oil-gas separator is connected to the engine through an oil return pipe 10. The compressed air drives the oil-gas separation filter element to rotate at a high speed, which is beneficial to increase the negative pressure in the closed-cycle crankcase 1.

[0027] Example 3

[0028] The oil-gas separation mechanism 3 is an oil-driven oil-gas separator. The oil inlet end of the oil-driven oil-gas separator is connected to the high-pressure oil main oil channel of the engine. The oil-driven oil-gas separator is installed on the engine body. The filtered oil of the oil-driven oil-gas separator flows directly back to the engine. The high-pressure oil drives the oil-gas separation filter element to rotate at a high speed, which is beneficial to increase the negative pressure in the closed-cycle crankcase 1.

[0029] The present invention can reduce the influence of the anti-surge pipe airflow on the ventilation pipe, increase the suction force of the compressor on the air in the crankcase, and effectively ensure that the pressure in the crankcase is stably lower than the atmospheric pressure, ensuring that the requirement of "GB17691-2018 Heavy Vehicle National VI Emission Standard" that the crankcase pressure is not greater than the atmospheric pressure is met.

[0030] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A structure for increasing negative pressure, comprising a closed cycle crankcase (1) and a supercharger (2), characterized in that: It also comprises an oil-gas separation mechanism (3), wherein the ventilation pipe (4) of the closed cycle crankcase (1) is connected to an air inlet (6) at the front end of a compressor (5) of the supercharger (2) through the oil-gas separation mechanism (3), the ventilation pipe (4) is located between an anti-surge valve pipe (7) of the supercharger (2) and the compressor (5), the spacing between the ventilation pipe (4) and the compressor (5) is smaller than the spacing between the ventilation pipe (4) and the anti-surge valve pipe (7), and one end of the ventilation pipe (4) connected to the air inlet (6) extends obliquely toward the compressor (5) or is provided with a first oblique cut (8) facing the compressor (5); One end of the anti-surge valve pipe (7) connected to the air inlet duct (6) extends obliquely in the direction away from the compressor (5) or is provided with a second oblique cut in the direction away from the compressor (5).

2. A structure for increasing negative pressure according to claim 1, characterized in that: The included angle between the anti-surge valve pipe (7) and the air intake duct (6) is 30° to 90°.

3. A structure for increasing negative pressure according to claim 1, characterized in that: The distance between the ventilation pipe (4) and the anti-surge valve pipe (7) is greater than 200 mm.

4. A structure for increasing negative pressure according to any one of claims 1 to 3, characterized in that: The oil-gas separation mechanism (3) is an oil-gas separator of model H100-140.

5. A structure for increasing negative pressure according to any one of claims 1 to 3, characterized in that: The oil-gas separation mechanism (3) is an air-driven oil-gas separator, and the compressed air inlet end of the air-driven oil-gas separator is connected to the automobile gas tank or the air inlet duct (6) at the rear end of the compressor (5) through an air pipe (9).

6. A structure for increasing negative pressure according to any one of claims 1 to 3, characterized in that: The oil-gas separation mechanism (3) is an oil-driven oil-gas separator, and the oil inlet end of the oil-driven oil-gas separator is connected to the high-pressure main oil channel of the engine.

Images