CN103256099A - Electric crankcase ventilation system - Google Patents

Abstract

The invention discloses an electric crankcase ventilation system and provides a ventilation system accurate in control. The electric crankcase ventilation system comprises a crankcase of an engine, an air incoming manifold, an oil-gas separator, an air filter and an air incoming hose, the crankcase is connected with an electric ventilation device through the oil-gas separator, the electric ventilation device comprises a check valve connected with the oil-gas separator, an output end of the check valve is connected with an input end of an electric air pump, an output end of the electric air pump is connected with the air incoming manifold, the electric air pump is controlled by a pressure start switch, a pressure detection end of the pressure start switch is communicated withe the crankcase, the air filter is connected with the air incoming manifold through the air incoming hose, and the air incoming manifold and the crankcase are communicated. The electric crankcase ventilation system can ba applied to various automobiles and has the advantages of capability of realizing real-time closed-loop control on pressure of the crankcase, high flow characteristic accuracy, good adaptability to working condition changes, and capability of normally working when the engine is in an inclined state or in high and low-temperature environments.

Description

Electric crankcase ventilation system

technical field

The invention belongs to the technical field of engines, and in particular relates to an engine crankcase ventilation system.

Background technique

The emission requirements of modern automobiles are becoming more and more stringent. The design of the crankcase ventilation system of the automobile engine has an important impact on the prevention of oil deterioration, dilution and emission. Most of the traditional crankcase ventilation systems use the crankcase forced ventilation device, which adjusts the pressure difference between the crankcase and the intake pipe through the mechanical PCV valve to control the amount of exhaust gas discharge, so that the crankcase pressure can be stabilized in an appropriate range Inside.

For example, China Patent Application No. 201110109535.9, an invention patent named "Engine Crankcase Ventilation System", discloses an engine crankcase ventilation system. The PCV valve is combined with the valve chamber cover body, the upper support plate and the lower support plate are installed at the bottom of the valve chamber cover body, the upper support plate and the valve chamber cover body form a closed cavity, and the upper support plate and the lower support plate form an oil return An air windshield is installed in the airtight cavity formed by the upper support plate and the valve chamber cover body, and an adsorbent is installed on the air windshield. The crankcase ventilation system is mainly composed of PCV valves, such as plunger PCV valves, which sense the pressure difference on both sides of the valve through springs and push the valve core to move to control the air flow. PCV valves have the following disadvantages:

1. The operating characteristic parameters of the PCV valve should be determined according to the comprehensive requirements of various engine operating conditions and the amount of blow-by gas in the crankcase under each operating condition. The calculation and design of the flow characteristics are not accurate enough and the design is difficult;

2. It is difficult to make accurate and timely adjustments according to different working conditions of the car, and cannot meet the technical requirements of the ideal crankcase pressure under all working conditions;

3. The PCV valve is easy to wear and cause air leakage, resulting in excessive idle speed and unstable speed;

4. It is easy to freeze in winter and cause stuck faults.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the defects of low flow characteristic accuracy, poor adaptability to working condition change, easy wear and tear, and easy freezing and jamming of the PCV valve used in the crankcase ventilation system of the prior art, and provide a Real-time closed-loop control of crankcase pressure difference to precisely control the crankcase ventilation system of the engine crankcase pressure.

The purpose of the present invention is achieved by the following technical solutions: an electric crankcase ventilation system, including the crankcase of the engine, intake manifold, oil-gas separator, air filter and intake hose, crankcase The electric ventilation device is connected through the oil-air separator, and the electric ventilation device includes a one-way valve connected with the oil-gas separator. The output end of the one-way valve is connected with the input end of the electric air pump, and the output end of the electric air pump is connected with the intake manifold. Connection, the electric air pump is controlled by the pressure start switch, and the pressure detection end of the pressure start switch is connected with the crankcase; the air filter is connected with the intake manifold through the intake hose, and the intake manifold is connected with the crankcase.

The exhaust gas in the crankcase enters the oil-air separator due to the pressure difference. The electric air pump extracts the exhaust gas from the oil-air separator through the check valve and sends it into the intake manifold. The action of the electric air pump is controlled by the pressure start switch. The detection value of crankcase exhaust gas pressure controls the action, and the whole system constitutes a closed-loop control system with accurate and stable control accuracy.

Preferably, the electric ventilation device performs closed-loop control in real time through pressure difference, and the precision of closed-loop control is 0.2kPa.

As preferably, the pressure start switch controls the switch of the circuit according to the size of the crankcase pressure of the engine. When the crankcase pressure is greater than a certain set value Px, the switch is connected, otherwise, when the crankcase pressure is less than a certain set value Px The switch is turned off, and the crankcase pressure setting value Px is set according to the characteristics of different engines.

As preferably, the pressure range of diesel engine crankcase is set at-2.5kPa～1kPa; The pressure range of gasoline engine crankcase is set at-2.5kPa～0kPa.

The beneficial effects of the present invention are:

1. The crankcase ventilation system controls the ventilation in a real-time closed loop by detecting the crankcase pressure difference, which can accurately control the engine crankcase pressure;

2. The exhaust gas from the crankcase is discharged through the electric air pump, with high accuracy of flow characteristics and good adaptability to changes in working conditions;

3. The crankcase ventilation system can work normally when the engine is in a tilted state or in a high or low temperature environment;

4. Effectively prevent oil deterioration, dilution, oil burning and oil seal leakage and other failures.

Description of drawings

Fig. 1 is a schematic block diagram of an embodiment of the present invention.

In the figure, crankcase 1; intake manifold 2; oil-air separator 3; air filter 4; intake hose 5; bypass 51; electric ventilation device 6; one-way valve 61; electric air pump 62; pressure Start switch 63; output tube 64; detection tube 65.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Embodiment: as shown in Figure 1, a kind of electric crankcase ventilation system comprises the crankcase 1 of engine, intake manifold 2, oil-gas separator 3, air filter 4 and intake hose 5, crankcase 1 The electric ventilation device 6 is connected through the oil-gas separator 3, the electric ventilation device 6 includes a one-way valve 61 connected with the oil-gas separator 3, the input end of the one-way valve 61 is connected with the oil-gas separator 3, and the one-way valve 61 The output end of the electric air pump 62 is connected with the input end of the electric air pump 62, the output end of the electric air pump 62 is connected with the intake manifold 2, the electric air pump 62 is controlled by the pressure start switch 63, and the pressure detection end of the pressure start switch 63 communicates with the crankcase 1; The air filter 4 is connected to the intake manifold 2 through the intake hose 5 , and the intake manifold 2 communicates with the crankcase 1 . The electric ventilation device 6 performs closed-loop control in real time through the pressure difference, and the precision of the closed-loop control is 0.2kPa.

The pressure start switch 63 detects the pressure inside the engine crankcase 1 through the detection tube 65, and controls the switch of the circuit according to the pressure inside the engine crankcase 1. When the crankcase pressure is greater than a certain set value Px, the switch is connected. Conversely, when the crankcase pressure is less than a certain set value Px, the switch is turned off, and the crankcase pressure set value Px is set according to the characteristics of different engines.

The pressure range of the diesel engine crankcase is set to -2.5kPa～1kPa; the pressure range of the gasoline engine crankcase is set to -2.5kPa～0kPa.

The exhaust gas in the crankcase 1 enters the oil-gas separator 3 due to the pressure difference, and the electric air pump 62 extracts the exhaust gas in the oil-air separator 3 through the one-way valve 61, and sends it into the intake manifold 2 through the output pipe 64, and the electric air pump 62 The action is controlled by the pressure start switch 63. The pressure start switch 63 controls the action according to the detection value of the exhaust gas pressure of the crankcase 1. The whole system constitutes a closed-loop control system with accurate and stable control accuracy, which can avoid various disadvantages of the mechanical ventilation device.

Specifically, after the engine starts running, the pressure in the crankcase of the engine will increase. When the pressure exceeds the set value Px, such as -2kPa, the pressure start switch 63 is turned on, and the electric air pump 62 is energized to start running, and the exhaust gas in the crankcase 1 is discharged into the intake manifold 2, and flows from the intake hose The mixed airflow of the engine participates in the combustion in the cylinder again, and part of the fresh air in the intake hose can directly enter the crankcase through the bypass 51 to supplement the crankcase pressure; when the pressure in the crankcase of the engine is less than the value Px, the pressure start switch 63 is closed, The electric air pump 62 is powered off and stops running, so that the pressure in the crankcase 1 is kept at -2kPa all the time. Therefore, the electric crankcase ventilation system can precisely control the engine crankcase pressure, so that the vehicle can obtain more satisfactory emission performance.

The invention can be applied in the crankcase ventilation systems of various automobiles, and has the advantages of real-time closed-loop control of the crankcase pressure, high accuracy of flow characteristics, good adaptability to changes in working conditions, and the crankcase can be operated in an inclined state of the engine or in a high or low temperature environment. The advantage that the ventilation system can work normally, if those skilled in the art make simple modifications or replacements to the above-mentioned content of the invention, such changes cannot be considered as departing from the scope of the present invention, and all such modifications obvious to those skilled in the art will included within the scope of the claims of the present invention.

Claims (4)

1. An electric crankcase ventilation system, including the crankcase of the engine, intake manifold, oil-air separator, air filter and intake hose, characterized in that the crankcase is connected with an electric-type ventilation system through the oil-air separator. Ventilation device, the electric ventilation device includes a one-way valve connected with the oil-gas separator, the output end of the one-way valve is connected with the input end of the electric air pump, the output end of the electric air pump is connected with the intake manifold, and the electric air pump is activated by the pressure switch Control, the pressure detection end of the pressure start switch communicates with the crankcase; the air filter connects with the intake manifold through the intake hose, and the intake manifold communicates with the crankcase. 2. The electric crankcase ventilation system according to claim 1, characterized in that the electric ventilation device performs closed-loop control in real time through pressure difference, and the closed-loop control accuracy is 0.2kPa. 3. The electric crankcase ventilation system according to claim 1 or 2, characterized in that the pressure start switch controls the switch of the circuit according to the crankcase pressure of the engine, when the crankcase pressure is greater than a certain set value Px When the switch is turned on, on the contrary, when the crankcase pressure is less than a certain set value Px, the switch is turned off, and the crankcase pressure set value Px is set according to the characteristics of different engines. 4. The electric crankcase ventilation system according to claim 3, wherein the pressure range of the diesel engine crankcase is set to -2.5kPa～1kPa; the pressure range of the gasoline engine crankcase is set to -2.5kPa～0kPa.

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