阅读说明：本技术 一种液压驱动可变气门正时机构 (Hydraulic drive variable valve timing mechanism ) 是由 孙常林 李琳 刘钢 于 2020-04-29 设计创作，主要内容包括：本发明公开了一种液压驱动可变气门正时机构,包括、低压系统和执行机构,所述高压系统、低压系统和执行结构分别连接ECU；高压系统设置溢流阀、回油管,在油压过高时及时泄油,保护系统,低压系统内设置稳压弹簧和限压滑块,通过限压滑块和泄油孔的配合,保证低压系统压力稳定,方便控制液压油的泄放量和速度。经试验,本液压驱动可变气门正时机构可降低25％的燃耗和二氧化碳排放,预热阶段的碳氢化合物排放最多可降低40％,氮氧化合物排放可降低60％。(The invention discloses a hydraulic drive variable valve timing mechanism, which comprises a low-pressure system and an execution mechanism, wherein the high-pressure system, the low-pressure system and the execution mechanism are respectively connected with an ECU (electronic control unit); the high-pressure system is provided with an overflow valve and an oil return pipe, oil is drained in time when the oil pressure is too high, the system is protected, a pressure stabilizing spring and a pressure limiting sliding block are arranged in the low-pressure system, the pressure stability of the low-pressure system is guaranteed through the matching of the pressure limiting sliding block and an oil drainage hole, and the drainage quantity and the speed of hydraulic oil are controlled conveniently. Through tests, the hydraulically-driven variable valve timing mechanism can reduce 25% of fuel consumption and carbon dioxide emission, the hydrocarbon emission in the preheating stage can be reduced by 40% at most, and the nitrogen oxide emission can be reduced by 60%.)

1. A hydraulically driven variable valve timing mechanism characterized in that: the system comprises a high-pressure system, a low-pressure system and an actuating mechanism, wherein the high-pressure system, the low-pressure system and the actuating mechanism are respectively connected with an ECU (electronic control unit);

the high-pressure system comprises a high-pressure common oil cavity, the high-pressure common oil cavity is connected with a high-pressure oil pump, and the high-pressure oil pump is connected with a hydraulic oil tank;

a pressure sensor is arranged in the high-pressure common oil cavity, an overflow valve is arranged in the high-pressure common oil cavity, and the overflow valve is connected to the hydraulic oil tank through an oil return pipe;

the low-pressure system comprises a low-pressure common oil cavity, the low-pressure common oil cavity comprises an oil inlet end and an oil return end, and a pressure stabilizing spring and a pressure limiting sliding block which is adaptive to the inner diameter of the oil return end are arranged in the oil return end;

an oil drain hole is formed in the oil return end, and the oil drain hole is connected to the hydraulic oil tank through a pipeline; when the pressure stabilizing spring is in a natural state, the distance between the pressure limiting slide block and the oil return end is greater than the distance between the oil drainage hole and the oil return end;

the actuating mechanism comprises a plurality of pistons, each piston is connected with an air valve, and an air valve spring is arranged between each piston and the corresponding air valve;

the piston is provided with a piston sleeve, an oil supply electromagnetic valve and a first one-way valve are connected between the high-pressure common oil cavity and the piston sleeve through oil pipes, a second one-way valve and an oil return electromagnetic valve are connected between the piston sleeve and the low-pressure common oil cavity through oil pipes, and an oil return hole is formed in the joint of the piston sleeve and the second one-way valve.

2. A hydraulically driven variable valve timing mechanism as set forth in claim 1, characterized in that: and a valve spring seat is arranged between the valve spring and the piston sleeve, and a laser displacement sensor is arranged on the valve spring seat.

3. A hydraulically driven variable valve timing mechanism as set forth in claim 2, characterized in that: the oil pipe is horizontally arranged, and the piston sleeve belong to a matching part and are vertically arranged above the valve spring.

4. A hydraulically driven variable valve timing mechanism as set forth in claim 1, characterized in that: the height of the piston top of the piston in a static state is larger than that of the oil return hole, and the height of the piston top of the piston in a working state is smaller than that of the oil return hole.

5. A hydraulically driven variable valve timing mechanism as set forth in claim 1, characterized in that: the valve comprises a valve rod and a valve seat, the upper end of the valve rod is connected with the piston, the lower end of the valve rod is arranged in a conical shape, and the valve seat is provided with a conical surface adaptive to the conical shape of the valve rod.

Technical Field

The invention relates to a valve timing mechanism, in particular to a hydraulically-driven variable valve timing mechanism.

Background

In the automotive industry, the engine is the most important part of the whole vehicle, and the engine has many components, and the valve train is the more important part of the engine. Most engines at present adopt fixed valve timing, and the optimal valve timing required by the engines under different working conditions is different, so that the performances of the engines under various working conditions can not be fully exerted by adopting a compromise method while considering the performances under various working conditions, and the development requirements of modern technologies can not be met in the aspects of economy, emission and dynamic property.

Application number CN201610579815.9 discloses an engine and a variable valve timing mechanism thereof, comprising a camshaft and a crankshaft with a preset rotation speed ratio transmission relationship, and further comprising a variable transmission ratio transmission assembly which is connected between the camshaft and the crankshaft in a power mode and used for adjusting the rotation speed ratio between the camshaft and the crankshaft. Wherein the variable ratio assembly's own gear ratio is variable and the gear ratio relationship between the camshaft and crankshaft is adjusted accordingly, either increased or decreased, so that the timing phase is advanced or retarded. The valve opening and closing is limited by the cam profile, the valve lift is large, the opening time is long, the pumping loss is increased, the economy is poor, and the working vibration and the noise are large due to the existence of the cam shaft.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at the defects in the prior art, the hydraulic drive variable valve timing mechanism is provided, a hydraulic system is used for driving the valve to open and close, a camshaft structure is omitted, the oil circuit arrangement is more flexible relative to the camshaft, the design space can be effectively improved, and the working vibration and noise can be reduced; the valve can be freely opened and closed without being limited by the cam profile, the air input is controlled through the valve lift and the opening time, the valve mechanism can be eliminated, the pumping loss is greatly reduced, and the economy is improved.

In order to solve the technical problems, the technical scheme of the invention is as follows:

a hydraulic drive variable valve timing mechanism comprises a high-pressure system, a low-pressure system and an actuating mechanism, wherein the high-pressure system, the low-pressure system and the actuating mechanism are respectively connected with an ECU (electronic control unit);

the high-pressure system comprises a high-pressure common oil cavity, the high-pressure common oil cavity is connected with a high-pressure oil pump, and the high-pressure oil pump is connected with a hydraulic oil tank;

a pressure sensor is arranged in the high-pressure common oil cavity, an overflow valve is arranged in the high-pressure common oil cavity, and the overflow valve is connected to the hydraulic oil tank through an oil return pipe;

the low-pressure system comprises a low-pressure common oil cavity, the low-pressure common oil cavity comprises an oil inlet end and an oil return end, and a pressure stabilizing spring and a pressure limiting sliding block which is adaptive to the inner diameter of the oil return end are arranged in the oil return end;

an oil drain hole is formed in the oil return end, and the oil drain hole is connected to the hydraulic oil tank through a pipeline; when the pressure stabilizing spring is in a natural state, the distance between the pressure limiting slide block and the oil return end is greater than the distance between the oil drainage hole and the oil return end;

the actuating mechanism comprises a plurality of pistons, each piston is connected with an air valve, and an air valve spring is arranged between each piston and the corresponding air valve;

the piston is provided with a piston sleeve, an oil supply electromagnetic valve and a first one-way valve are connected between the high-pressure common oil cavity and the piston sleeve through oil pipes, a second one-way valve and an oil return electromagnetic valve are connected between the piston sleeve and the low-pressure common oil cavity through oil pipes, and an oil return hole is formed in the joint of the piston sleeve and the second one-way valve.

As a preferred technical scheme, a valve spring seat is arranged between the valve spring and the piston sleeve, and a laser displacement sensor is arranged on the valve spring seat.

As a preferred technical scheme, the oil pipe is horizontally arranged, and the piston sleeve belong to a matching part and are vertically arranged above the valve spring.

As a preferable technical solution, the height of the top of the piston in a static state is greater than the height of the oil return hole, and the height of the top of the piston in a working state is less than the height of the oil return hole.

Due to the adoption of the technical scheme, the invention has the beneficial effects that:

the invention discloses a hydraulic drive variable valve timing mechanism, which comprises a high-pressure system, a low-pressure system and an actuating mechanism, wherein the high-pressure system, the low-pressure system and the actuating mechanism are respectively connected with an ECU (electronic control unit); the high-pressure system comprises a high-pressure common oil cavity, the high-pressure common oil cavity is connected with a high-pressure oil pump, and the high-pressure oil pump is connected with a hydraulic oil tank; a pressure sensor is arranged in the high-pressure common oil cavity, an overflow valve is arranged in the high-pressure common oil cavity, and the overflow valve is connected to the hydraulic oil tank through an oil return pipe; the low-pressure system comprises a low-pressure common oil cavity, the low-pressure common oil cavity comprises an oil inlet end and an oil return end, and a pressure stabilizing spring and a pressure limiting sliding block are arranged in the oil return end; an oil drain hole is formed in the oil return end, and the oil drain hole is connected to the hydraulic oil tank through a pipeline; when the pressure stabilizing spring is in a natural state, the distance between the pressure limiting slide block and the oil return end is greater than the distance between the oil drainage hole and the oil return end; the actuating mechanism comprises a plurality of pistons, each piston is connected with an air valve, and an air valve spring is arranged between each piston and the corresponding air valve; the piston is provided with a piston sleeve, an oil supply electromagnetic valve and a first one-way valve are connected between the high-pressure common oil cavity and the piston sleeve through oil pipes, a second one-way valve and an oil return electromagnetic valve are connected between the piston sleeve and the low-pressure common oil cavity through oil pipes, and an oil drainage hole is formed in the joint of the piston sleeve and the second one-way valve. The high-pressure oil pump pumps the hydraulic oil out of the hydraulic oil tank, the hydraulic oil is filtered and pressurized and then stored in a high-pressure common oil cavity, and a pressure sensor is arranged in the high-pressure common oil cavity and used for providing an oil pressure signal for the ECU and controlling high-pressure; meanwhile, an overflow valve and an oil return pipe are arranged, so that oil can be drained timely when the oil pressure is too high, and the system is protected. The pressure-stabilizing spring and the pressure-limiting slide block which is matched with the inner diameter of the oil return end are arranged in the low-pressure system, and the pressure stability of the low-pressure system is ensured through the matching of the pressure-limiting slide block and the oil drain hole, so that the release amount and speed of hydraulic oil are conveniently controlled. Through tests, the hydraulically-driven variable valve timing mechanism can reduce 25% of fuel consumption and carbon dioxide emission, the hydrocarbon emission in the preheating stage can be reduced by 40% at most, and the nitrogen oxide emission can be reduced by 60%.

According to the invention, a valve spring seat is arranged between the valve spring and the piston sleeve, a laser displacement sensor is arranged on the valve spring seat, the oil pipe is horizontally arranged, and the piston sleeve belong to a matching coupling part and are vertically arranged above the valve spring. And monitoring the opening and closing motion condition of the valve in real time through a laser displacement sensor and forming a valve displacement signal, wherein the valve displacement signal is used as a correction parameter of an electromagnetic valve opening and closing control signal.

The height of the piston top of the piston in a static state is larger than that of the oil return hole, and the height of the piston top of the piston in a working state is smaller than that of the oil return hole. When the valve needs to be closed, the automobile ECU controls the oil drainage electromagnetic valve to be opened, high-pressure oil flows into the low-pressure system through the second one-way valve, the valve spring pushes the valve to return, when the valve is about to be seated, the piston moves upwards, the head gradually shields the oil return hole, the flow area is reduced, the seating speed of the valve is reduced, impact is reduced, the valve is protected, and meanwhile the engine runs more stably.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a schematic structural diagram of an embodiment of the present invention;

FIG. 2 is a schematic view of the actuator of FIG. 1;

FIG. 3 is a cross-sectional view taken along A-A of FIG. 2;

FIG. 4 is a schematic illustration of the high pressure system of FIG. 1;

FIG. 5 is a schematic view of the low pressure system of FIG. 1;

FIG. 6 is a schematic view of the low pressure common gallery of FIG. 5;

FIG. 7 is a functional schematic of the present invention;

in the figure, 1. high pressure system; 2. a low pressure system; 3. an actuator; 4. a hydraulic oil tank; 5. a high pressure common oil chamber; 51. a pressure sensor; 6. an overflow valve; 7. an oil return pipe; 8. an oil supply solenoid valve; 9. a first check valve; 10. a second one-way valve; 11. an oil return electromagnetic valve; 12. a piston sleeve; 13. a valve spring; 14. an air valve; 15. a valve spring seat; 16. a laser displacement sensor; 17. a piston; 18. an oil pipe; 19. a low pressure common oil chamber; 191. a pressure stabilizing spring; 192. a pressure limiting slider; 193. an oil drainage hole; 20. a high-pressure oil pump; 21. an oil return hole; 22. a valve stem; 23. a valve seat.

Detailed Description

The invention is further illustrated below with reference to the figures and examples.

Referring to fig. 1 to 7, a hydraulically-driven variable valve timing mechanism comprises a high-pressure system 1, a low-pressure system 2 and an actuating mechanism 3, wherein the high-pressure system 1, the low-pressure system 2 and the actuating mechanism 3 are respectively connected with an ECU; the ECU is integrated with a control program.

The high-pressure system 1 is a special hydraulic system, the high-pressure system 1 includes a high-pressure common oil chamber 5, the high-pressure common oil chamber 5 is connected with a high-pressure oil pump 20, and in this embodiment, the high-pressure oil pump 20 is of a type: 2.5PCY14-1B constant pressure plunger pump, the output pressure can be adjusted steplessly between 10MPa and 31.5MPa, the maximum transmission power is 1.43 kw; the high-pressure oil pump 20 is connected with a hydraulic oil tank 4; the high-pressure oil pump 20 is installed at the front end of the engine, and is directly driven by the crankshaft through a gear, and is driven by the crankshaft to establish a stable high-pressure system 1, and how the high-pressure oil pump 20 is driven by the crankshaft is common knowledge in the art and is not described herein again. In the embodiment, the engine is selected from Beiqi Futian BJ486 gasoline series, the model is as follows: the engine is an in-line four-cylinder engine, the diameter of a cylinder is 86mm, 4 intake and exhaust valves are arranged in each cylinder, a high-pressure oil pump 20 extracts hydraulic oil from a hydraulic oil tank 4, and the hydraulic oil is filtered, pressurized and stored in a high-pressure common oil cavity 5.

A pressure sensor 51 is arranged in the high-pressure common oil cavity 5, an overflow valve 6 is arranged in the high-pressure common oil cavity 5, and the overflow valve 6 is connected to the hydraulic oil tank 4 through an oil return pipe 7; in this embodiment, the pressure sensor is a kirschner digital pressure sensor, and the model is: GP-M400, rated pressure of 0-40 MPa, adjustable output response of 3-5000 ms.

The low-pressure system 2 is a special hydraulic system, the low-pressure system 2 comprises a low-pressure common oil cavity 19, the low-pressure common oil cavity 19 comprises an oil inlet end and an oil return end, and a pressure stabilizing spring 191 and a pressure limiting sliding block 192 are arranged in the oil return end; the oil return end is provided with an oil drain hole 193, and the oil drain hole 193 is connected to the hydraulic oil tank 4 through a pipeline; when the pressure stabilizing spring 191 is in a natural state, the distance between the pressure limiting slide block 192 and the oil return end is greater than the distance between the oil drain hole 193 and the oil return end; when the pressure in the low-pressure system 2 rises, the pressure limiting slide block 192 and the pressure stabilizing spring 191 are pressed to move, so that the oil drainage hole 193 is opened, and oil drainage is reduced in pressure; after the pressure is reduced, the pressure limiting slide 192 and the pressure stabilizing spring 191 are restored to the original positions, and the pressure of the low-pressure system 2 is kept stable.

The actuating mechanism comprises a plurality of pistons 17, the engine selected in the embodiment is an in-line four-cylinder engine, the diameter of the cylinder is 86mm, each cylinder is provided with 4 intake and exhaust valves 14, each valve 14 corresponds to one piston 17, and a valve spring 13 is arranged between each piston 17 and each valve 14; the valve is provided with a valve rod 22 and a valve seat 23, the upper end of the valve rod 22 is connected with the piston 17, the lower end of the valve rod 22 is arranged in a conical shape, and the valve seat 23 is provided with a conical surface adaptive to the conical shape of the valve rod 22. The piston 17 outside is equipped with piston cover 12, piston 17 and piston cover 12 belong to and pair the idol piece, vertical installation in valve spring 13 top, high-pressure public oil chamber 5 with be connected with oil feed solenoid valve 8 and first check valve 9 through oil pipe 18 between the piston cover 12, piston cover 12 with be connected with second check valve 10 and oil return solenoid valve 11 through oil pipe 18 between the public oil chamber 19 of low pressure, piston cover 12 with second check valve 10 junction is equipped with oil return hole 21, in this embodiment the oil feed solenoid valve with the oil return solenoid valve all chooses power shile high frequency electromagnetic valve 4WRPDH series for use, and highest operating pressure 35MPa, check valve choose power shile check valve Z1S6 series for use.

The height of the top of the piston 17 in a static state is greater than that of the oil return hole 21, and the height of the top of the piston 17 in a working state is less than that of the oil return hole 21. Valve spring 13 with be equipped with valve spring seat 15 between the piston cover 12, be equipped with laser displacement sensor 16 on the valve spring seat 15, in this embodiment the displacement sensor chooses for use kirschner CMOS laser displacement sensor, the model: IL-065, the reference distance is 65mm, the sampling period is variable in 4 stages, the minimum period is 0.33ms, the oil pipe 18 is horizontally arranged, and the piston 17 and the piston sleeve 12 belong to a matching part and are vertically arranged above the valve spring 13. The laser displacement sensor 16 monitors the opening and closing motion conditions of the valve 14 in real time and forms a valve position signal which is fed back to the ECU, and the valve position signal is used as a correction parameter of the opening and closing control signals of the oil supply electromagnetic valve 8 and the oil return electromagnetic valve 11.

The normal working pressure of the high-pressure system 1 is 10-15 Mpa, when the valve 14 needs to be opened, the oil supply electromagnetic valve 8 and the first one-way valve 9 are opened, high-pressure hydraulic oil enters the piston sleeve 12 and compresses the piston 17 to move downwards, the piston 17 pushes the valve 14 to move downwards, the valve spring 13 is compressed in the downward movement process of the valve 14, the valve 14 is opened and air is fed at the moment, when the pressure of the high-pressure system 1 exceeds 15Mpa, the ECU controls the overflow valve 6 to be opened for pressure relief, when the pressure of the high-pressure system 1 reaches 10Mpa, the ECU controls the overflow valve 6 to be closed, the system pressure is kept in a normal range, and damage to equipment is prevented.

The working pressure of the low-pressure system is 0.5-1.5 Mpa, when the air valve 14 needs to be closed, the oil supply solenoid valve 8 and the first one-way valve 9 are closed, the second one-way valve 10 and the oil return solenoid valve 11 are opened, hydraulic oil flows into the low-pressure system 2, the pressure in the low-pressure system 2 rises, the pressure limiting slide block 192 and the pressure stabilizing spring 191 move under pressure, when the pressure in the low-pressure system 2 rises to 1.5Mpa, the oil drainage hole 193 is opened, and oil drainage is depressurized; when the pressure in the low-pressure system 2 is reduced to 0.5Mpa, the pressure limiting slide block 192 blocks the oil drainage hole 193 to prevent oil from draining, the pressure of the low-pressure system 2 is kept stable, meanwhile, the piston 17 moves upwards, the valve spring 13 resets to drive the valve 14 to move upwards to be seated and closed, when the valve 14 is seated, the head of the piston 17 shields part of the oil return hole 21, the flow area is reduced, the seating buffer of the valve 14 is realized, the impact is reduced, the noise is reduced, and the valve 14 is protected.

The specific working process of the invention is as follows:

the ECU receives signals of the pressure sensor 51, the oil supply electromagnetic valve 8, the oil return electromagnetic valve 11, the laser displacement sensor and other sensors, gives instructions to control the oil supply electromagnetic valve 8 and the oil return electromagnetic valve 11 to work by integrating the driving condition of the automobile and the intention of a driver, controls the opening and closing time of the valve 14 through the high-pressure system 1 and the low-pressure system 2 by controlling the opening and closing time of the oil supply electromagnetic valve 8 and the oil return electromagnetic valve 11, and accordingly realizes full variation of the lift and the gas distribution phase of the valve 14.

(1) When the engine runs at a high speed:

air intake: because the air intake rate is very high, the ECU increases the opening duration of the oil supply electromagnetic valve 8, so that the air intake delay-closing angle is increased, the inertia of air flow is fully utilized, and the air intake quantity is improved. The increase of the air input can well improve the dynamic property of the engine under the high-speed working condition.

Exhaust: in order to smoothly discharge the exhaust gas, the ECU needs to open the drain solenoid valve 11 in advance, thereby increasing the exhaust advance angle and improving the exhaust.

(2) When the engine runs at low speed:

air intake: because the inertia of the air flow is very small at this time, the ECU reduces the opening duration of the oil supply electromagnetic valve 8, thereby reducing the air inlet delay-closing angle and preventing the air from flowing backwards.

Exhaust: the ECU delays to open the oil drain electromagnetic valve 11, so that the exhaust advance angle is reduced, the piston can fully work, and the fuel economy of the engine is improved.

Tests show that the hydraulically-driven variable valve timing mechanism can reduce 25% of fuel consumption and carbon dioxide emission, the hydrocarbon emission in the preheating stage can be reduced by 40% at most, and the nitrogen oxide emission can be reduced by 60%.

It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.