Combined crankcase ventilation system of diesel engine

Abstract

The utility model discloses a combined crankcase ventilation system of a diesel engine, which belongs to the technical field of engines and comprises a flow guide box and a respirator arranged on a gas outlet arranged at the top of the flow guide box, a gas inlet of the flow guide box is connected with a waste gas outlet of a crankcase, and the bottom of the flow guide box is arranged to be an inclined plane. An oil return opening is formed in the lowest point of the bottom. According to the design method of the combined crankcase ventilation system of the diesel engine, on the basis of a prototype ventilation system, the overall performance of the ventilation system is improved through the combined design, and the combined crankcase ventilation system can meet the matching requirements of performance improvement or series development of various diesel engines.

Description

Technical Field

[0001] This utility model belongs to the field of engine technology, specifically relating to a combined crankcase ventilation system for diesel engines. Background Technology

[0002] Diesel engine power is primarily increased by increasing displacement, raising engine speed, and improving combustion. The basic approach is to burn more fuel and air in the cylinder, which, while increasing power, also produces more crankcase gas. In piston-type diesel engines, the piston rings between the piston and cylinder liner cannot completely seal off the high-pressure gas inside the cylinder. Therefore, some gas is forced into the crankcase. This gas mixes with the oil and gas already generated in the crankcase, forming crankcase exhaust gas. Excessive crankcase exhaust gas can lead to problems such as oil seal failure and increased pumping losses. Therefore, diesel engines must be equipped with crankcase ventilation systems, and these systems must be designed with higher displacement and filtration capabilities. This exhaust gas is expelled from the crankcase, and the lubricating oil particles contained within are filtered and returned to the diesel engine, reducing lubricating oil consumption and protecting the environment.

[0003] Developing crankcase ventilation devices with larger flow rates inevitably requires increasing the volume and filtration capacity of the crankcase ventilation devices, resulting in problems such as large size, high development difficulty, high manufacturing cost, and low reliability, which are not conducive to product design and promotion.

[0004] According to the general design scheme, the research and development unit will calculate the piston leakage of the new product based on the single-cylinder piston leakage of the prototype, and use the total piston leakage parameter of the diesel engine as the crankcase exhaust flow rate. Combined with the pressure control requirements in the crankcase, a special crankcase ventilation device will be developed by a professional supporting unit. Utility Model Content

[0005] The purpose of this utility model is to provide a combined crankcase ventilation system for diesel engines. Without changing the original design of the ventilation system, the system integrates crankcase exhaust gas through an integrated design, thereby improving the crankcase ventilation capacity of the diesel engine.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0007] A combined crankcase ventilation system for a diesel engine includes a baffle box and a breather installed on the air outlet at the top of the baffle box. The air inlet of the baffle box is connected to the exhaust outlet of the crankcase. The bottom of the baffle box is sloped, and an oil return port is provided at the lowest point of the bottom.

[0008] A further improvement of this utility model is that the air inlet of the air guide box is located on the side of the air guide box, and the position of the air inlet is offset from the position of the nearest air outlet of the air guide box in the horizontal direction.

[0009] A further improvement of this utility model is that: the guide slope at the bottom of the guide box is inclined from the air inlet to the oil return port, and the inclination angle between the guide slope and the horizontal plane is β. The rear side wall of the guide box includes a straight plate and an inclined plate, and the inclined plate is connected to the guide slope at the bottom of the guide box. The inclination angle between the inclined plate and the horizontal plane is α, where α>β.

[0010] A further improvement of the present invention is that α is 27°±2° and β=1 / 2α.

[0011] A further improvement of this utility model is that the air outlet is a number of pipes located on the top of the guide box and extending into the interior of the guide box, and the number of respirators is the same as the number of air outlets.

[0012] A further improvement of this utility model is that: the air outlet is provided with an air hole on the side wall of the pipe inside the guide box, and the inner diameter of the air hole is 6 mm to 8 mm.

[0013] A further improvement of this utility model is that the air inlet of the guide box and the exhaust outlet of the crankcase have the same flow cross-section.

[0014] A further improvement of this utility model is that the guide box is installed vertically above the diesel engine's rear oil return port.

[0015] The technological advancements achieved by this utility model due to the adoption of the above technical solution are as follows:

[0016] This application discloses a design method for a combined crankcase ventilation system for diesel engines. Based on the prototype engine ventilation system, the method achieves an overall performance improvement of the ventilation system through modular design, which can be applied to the matching needs of performance improvement or serial development of various types of diesel engines.

[0017] Compared to the newly developed high-flow crankcase ventilation device, the technical solution of this application is easier to implement and avoids the problems of immature technology, manufacturing difficulty and high cost of the new respirator. Attached Figure Description

[0018] Figure 1 This is a top view of the air guide box of this utility model;

[0019] Figure 2 yes Figure 1 AA cross-sectional view and schematic diagram of the respirator;

[0020] Figure 3 yes Figure 2 BB section view;

[0021] Figure 4 This is a schematic diagram illustrating the working principle of the crankcase ventilation system;

[0022] Among them, 1. air inlet, 2. air guide box, 3. oil return port, 4. air outlet, 5. breather, 6. air hole. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to embodiments:

[0024] like Figure 1-3 As shown, a combined crankcase ventilation system for a diesel engine includes a baffle box 2 and a breather 5. The breather 5 is installed on the outlet 4 at the top of the baffle box. The inlet 1 of the baffle box 2 is connected to the exhaust outlet of the crankcase. The bottom of the baffle box 2 is sloped, and an oil return port 3 is located at the lowest point of the bottom. The inlet 1 of the baffle box and the exhaust outlet D of the crankcase are directly connected, and their function is to guide the exhaust gas in the crankcase into the baffle box 2. The flow cross-sections of the inlet 1 of the baffle box and the exhaust outlet D of the crankcase are the same, and the cross-sectional size is controlled according to the total exhaust gas flow rate of the diesel engine and the pressure in the crankcase. The function of the baffle box 2 is to guide the exhaust gas and the filtered oil separately. Its volume is determined by the installation space of the breather 5 and has no special requirements.

[0025] Multiple air outlets 4 on the top of the air guide box can be designed according to actual needs, and a respirator 5 can be installed on them.

[0026] The air inlet 1 of the baffle box is located on the side of the baffle box 2. In order to make the exhaust gas entering the multiple breathers 5 equal, the air inlet 1 is horizontally offset from the nearest air outlet 4 of the baffle box, so that the exhaust gas enters the breathers 5 more evenly.

[0027] The guide slope at the bottom of the guide box slopes from the air inlet 1 to the oil return port 3, with an inclination angle β between the guide slope and the horizontal plane. The rear side wall of the guide box 2 includes a straight plate and an inclined plate disposed below the straight plate. The inclined plate is connected to the guide slope at the bottom of the guide box. Figure 3 As shown, the angle of inclination of the inclined plate to the horizontal plane is α, where α > β.

[0028] In a preferred embodiment, the inclined plate at α is the surface where the oil droplets returning from the breather 5 directly drip. Since the oil volume is small, the angle of the inclined plate should be large in order to make the oil flow down quickly. This can be obtained by testing the flow of 100° lubricating oil droplets on the inclined plate. When the diesel engine is working horizontally, it can generally be set to 27°±2°. The guide inclined plate at β collects the oil filtered by each breather 5. Since the oil volume is large, the angle can be designed to be relatively gentle, which can be designed to be 1 / 2 of α.

[0029] The air outlets 4 are several pipes located at the top of the guide box and extending into the interior of the guide box. The number of breathers 5 is the same as the number of air outlets 4. The function of the air outlets 4 in the guide box is to install the breathers 5. The lower part of each air outlet 4 remains open to allow the filtered oil to flow smoothly down. The air outlets 4 have air holes 6 on the side wall of the pipes inside the guide box, with an inner diameter of 6 mm to 8 mm. The air holes 6 are used for exhaust gas to enter the breathers 5, and the air holes also have the function of preliminary filtration of large oil droplets in the exhaust gas.

[0030] The flow guide box 2 can be equipped with N breathers according to the total exhaust gas flow requirements, and can be freely combined during product series development, such as... Figure 1 The diagram shows that three respirators can be installed to meet the prototype's requirement of three times the exhaust gas flow rate.

[0031] The function of the return port 3 of the guide box is to return the lubricating oil filtered by the breather 5 back to the diesel engine. Its inner diameter should be relatively small. After the guide box 2 is installed on the diesel engine, the return port 3 is vertically higher than the diesel engine. That is, there should be a certain vertical height between the return port 3 and the diesel engine so that the oil can flow back quickly when there is a large accumulation of oil or when the diesel engine is working at an angle. The specific height is designed according to the working conditions of the diesel engine.

[0032] Working principle or usage method:

[0033] Its working principle is as follows Figure 4 As shown, Figure 4 This is a crankcase ventilation device. The triangular arrow indicates the direction of exhaust gas flow. A small amount of exhaust gas produced by combustion in the cylinder enters the crankcase A through the gap between the piston ring and the cylinder. It mixes with the splashed and evaporated oil in the crankcase A to form crankcase exhaust gas. The exhaust gas enters the valve distribution chamber B and the exhaust gas flow stabilization chamber C in sequence, so that the larger oil droplets in the exhaust gas return directly to the oil pan. The exhaust gas containing smaller oil droplets enters the guide box 2 from the exhaust gas outlet D and is discharged after being filtered by the breather 5.

[0034] Due to the insufficient ventilation capacity of diesel engine crankcases, the development of crankcase ventilation devices with larger flow rates inevitably requires increasing the volume and filtration capacity of the crankcase ventilation devices. This results in problems such as large size, high development difficulty, high manufacturing cost, and low reliability of the crankcase ventilation devices, which are not conducive to product design and promotion.

[0035] The present invention provides a combined crankcase ventilation system for diesel engines, which is a combined design scheme based on the mature crankcase ventilation system of the prototype. It designs a flow guide box structure with flow guiding characteristics to improve the performance of the ventilation system.

Claims

1. A combined crankcase ventilation system for a diesel engine, characterized in that: It includes a guide box (2) and a breather (5) installed on the air outlet (4) set on the top of the guide box. The air inlet (1) of the guide box (2) is connected to the exhaust outlet of the crankcase. The bottom of the guide box (2) is set with a slope, and the lowest point of the bottom is set with an oil return port (3).

2. The combined crankcase ventilation system for a diesel engine according to claim 1, characterized in that: The air inlet (1) of the air guide box (2) is located on the side of the air guide box, and the air inlet (1) is horizontally offset from the air outlet (4) of the nearest air guide box.

3. A combined crankcase ventilation system for a diesel engine according to claim 1, characterized in that: The guide slope at the bottom of the guide box is inclined from the air inlet (1) to the oil return port (3). The angle of inclination of the guide slope with respect to the horizontal plane is β. The rear side wall of the guide box (2) includes a straight plate and an inclined plate set below the straight plate. The inclined plate is connected to the guide slope at the bottom of the guide box. The angle of inclination of the inclined plate with respect to the horizontal plane is α, where α>β.

4. A combined crankcase ventilation system for a diesel engine according to claim 2, characterized in that: The air outlet (4) consists of several pipes located on the top of the flow guide box and extending into the flow guide box. The number of respirators (5) is the same as the number of air outlets (4).

5. A combined crankcase ventilation system for a diesel engine according to claim 3, characterized in that: The value of α is 27°±2°, and β=1 / 2α.

6. A combined crankcase ventilation system for a diesel engine according to claim 5, characterized in that: The air outlet (4) has an air hole (6) on the side wall of the pipe inside the guide box, and the inner diameter of the air hole is 6 mm to 8 mm.

7. A combined crankcase ventilation system for a diesel engine according to claim 1, characterized in that: The air inlet (1) of the guide box and the exhaust outlet of the crankcase have the same flow cross section.

8. A combined crankcase ventilation system for a diesel engine according to claim 1, characterized in that: The guide box (2) is installed at the oil return port (3) of the diesel engine, vertically above the diesel engine.

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