CN101363337B - variable valve lift valve train - Google Patents

Abstract

The utility model relates to a variable valve lift gas distribution mechanism for a reciprocating piston engine, which belongs to the fields of machinery and thermal power. The mechanism is composed of camshaft, hydraulic pump, hydraulic cylinder, valve, etc. The camshaft drives the hydraulic pump, and the hydraulic pump drives the hydraulic cylinder to open and close the valve. The engine control unit controls the amount of oil pumped by the hydraulic pump through actuators such as stepping motors, thereby controlling the opening of the valve. This mechanism can steplessly adjust the opening of each cylinder valve under the control of the engine control unit. In this way, the engine control unit can make some cylinders not work according to the engine load; some cylinders have a large load; In addition, this mechanism can control the intake air volume of the cylinder through the opening of the valve, thereby eliminating the throttle valve of the gasoline engine and increasing the specific power of the engine.

Description

variable valve lift valve train

technical field

The invention relates to a variable valve lift gas distribution mechanism of a reciprocating piston engine, which belongs to the fields of machinery and thermal power.

Background technique

At present, the most widely known engine is a reciprocating piston engine, which is used in vehicles, trains, ships and other vehicles. It is composed of crank connecting rod mechanism, gas distribution mechanism, cooling system, fuel supply system, ignition system, lubrication system and so on. The valve train consists of a valve train and a valve group. The valves work according to certain rules according to the working sequence of each cylinder, and cannot be controlled independently. Experiments show that the highest efficiency of gasoline engine is about 30%, and the highest efficiency of diesel engine is about 40%. The highest efficiency occurs when the engine is close to full load, and most engines (such as: engines used in vehicles, trains, ships, etc.) work most of the time under small and medium load conditions. Under small and medium loads, the efficiency of the engine is far below its peak efficiency, resulting in a lot of waste of fuel. The more effective way to solve this problem is to close some cylinders under small and medium loads to increase the load rate of the working cylinders. The traditional valve mechanism cannot realize the function of closing the cylinder because the valve cannot be controlled independently. In addition, the currently used gasoline engines have a throttle valve, which hinders the intake air and affects the charge coefficient of the cylinder, thereby reducing the specific power of the engine.

Contents of the invention

In order to overcome the problems of low load rate, low efficiency, large fuel waste and low specific power of existing engines, the present invention provides a variable valve lift valve mechanism, which can be adjusted steplessly under the control of the engine control unit The opening of each cylinder valve. In this way, the engine control unit can make some cylinders not work according to the engine load; some cylinders have a large load; In addition, this mechanism can control the intake air volume of the cylinder through the opening of the valve, so that the throttle valve of the gasoline engine can be omitted, and the specific power of the engine can be improved.

The technical solution adopted by the present invention to solve its technical problems is: the difference between the present invention and the traditional gas distribution mechanism is that the traditional gas distribution mechanism is composed of parts such as a camshaft, a tappet, a push rod, a rocker arm, and a valve. It is determined by the lift of the camshaft and cannot be adjusted or controlled separately. And this mechanism is made up of camshaft, hydraulic pump, hydraulic cylinder, valve etc., and camshaft drives hydraulic pump, and hydraulic pump drives hydraulic cylinder to make valve opening and closing. Hydraulic pump adopts class vane pump (as embodiment 2,3) or deformed vane pump (as embodiment 1), the rotor (17) of class vane pump and the center-to-center distance of pump casing (18) can be changed, so the pump oil volume just can be changed, the valve lift can be changed; the deformed vane pump can change the pump oil volume by rotating and swinging the pump body (14). The engine control unit controls the pumping volume of each hydraulic pump through actuators such as stepping motors, thereby controlling the opening of each valve.

The beneficial effect of the invention is that the load rate and efficiency of the working cylinder are improved through the closed-cylinder control, and the fuel consumption is reduced. And by removing the throttle valve of the gasoline engine, the specific power of the engine is improved.

Description of drawings

Fig. 1 is a structural principle diagram of the first embodiment of the variable valve lift valve train

Figure 2 is a sectional view of A-A in Figure 1

Fig. 3 is a structural principle diagram of the second embodiment of the variable valve lift valve train

Marks in the figure: 1. Valve control cylinder, 2. Cylinder head, 3. Cylinder piston, 4. Oil passage, 5. Camshaft, 6. Movable pump body, 7. Vane, 8. Shaft, 9. Valve lift adjustment Pull rod, 10. Air valve, 11. Guide key, 12. Active pump body return spring, 13. Pump body, 14. Swing pump body, 15. Baffle plate, 16. Rocker arm, 17. Rotor, 18. Pump casing, 19. Tie rod.

Detailed ways

Embodiment 1: as shown in Fig. 1, Fig. 2, this mechanism is made up of camshaft (5), hydraulic pump, hydraulic cylinder, air valve etc. The hydraulic pump is a deformed vane pump, which consists of a movable pump body (6), a swing pump body (14), front and rear baffles (15), blades (7), a movable pump body return spring (12), and a valve lift adjustment rod ( 9) Etc. composition. The movable pump body (6) can move up and down along the guide key (11), the swing pump body (14) can swing around the shaft (8) driven by the valve lift adjustment rod (9), and the blade (7) can move in its groove Stretch inside. The hydraulic cylinder is composed of a valve control oil cylinder (1), an oil cylinder cover (2), an oil cylinder piston (3) and the like. A spring is arranged between the oil cylinder cover (2) and the oil cylinder piston (3) to ensure that the oil cylinder piston (3) contacts with the valve (10) all the time. An oil passage (4) is connected between the hydraulic cylinder and the hydraulic pump. When the engine is working, the camshaft (5) rotates and pushes the movable pump body (6) to move downward, and the vane (7) slides on the swing pump body (14). At this time, the movable pump body (6), the swing pump body (14) ), the closed space surrounded by two vanes (7) and the front and rear baffles (15) shrinks, the internal oil pressure rises, and the oil flows to the hydraulic cylinder through the oil passage (4), pushing the cylinder piston (3) downward movement to open the valve (10). Along with the rotation of the camshaft (5), the movable pump body (6) moves upward under the promotion of the movable pump body return spring (12). The closed space surrounded by the movable pump body (6), the swing pump body (14), the two blades (7) and the front and rear baffles (15) increases, and the internal oil pressure decreases, and the pressure of the valve return spring Under action, the machine oil in the hydraulic cylinder flows to the hydraulic pump, the oil cylinder piston (3) rises, and the valve (10) closes. The engine control unit drives the valve lift adjustment rod (9) through actuators such as stepping motors to make the swing pump body (14) swing, so when the movable pump body (6) runs up and down, the volume change of the above-mentioned closed space changes. , thereby changing the lift of the valve (10). When the swing pump body (14) was parallel with the movable pump body (6), the air valve (10) would no longer be opened. Therefore, the engine control unit can control the lift of each valve at will, thereby controlling the intake air volume and working state of each cylinder separately, realizing the cylinder deactivation control of the engine and the control of different load rates among cylinders, and achieving the purpose of fuel saving. Of course, the throttle of the gasoline engine can be removed, thereby increasing the specific power of the engine. When we increase the throttle, the lift of the valve is controlled by the engine control unit to increase the power of the engine.

Embodiment 2: As shown in Figure 3, the difference from Embodiment 1 is the hydraulic pump, which is similar to a common vane pump, so we call it a quasi-vane pump. Its rotor (17) is connected with the rocker arm (16) and rotates together, and the pump casing (18) can move left and right under the drive of the pull rod (19), thereby changing the center distance between the pump casing (18) and the rotor (17). When the engine is working, the camshaft (5) drives the rotor (17) to swing through the rocker arm (16), so that the closed space at the lower part of the vane pump changes, and the oil cylinder piston (3) moves through the oil passage (4), thereby pushing the valve Opening and closing. Changing the center-to-center distance of the rotor (17) and the pump housing (18) has just changed the pump oil volume of the class vane pump, and has also just changed the lift of the valve. When the center distance is zero, the valve is closed. If the intake and exhaust valves of a cylinder are closed, the cylinder stops working, which is what we call closed cylinder. The engine control unit can drive the pull rod (19) and the pump casing (18) to move left and right with actuators such as stepping motors to control the lift of the valve, realize the control of cylinder closing of the engine and the control of different load rates between cylinders, and achieve fuel saving the goal of. Of course, the throttle of the gasoline engine can be removed, thereby increasing the specific power of the engine.

Embodiment 3: As shown in Figure 3, the upper half of the vane-like pump is removed. It can be seen from Embodiment 2 that the upper half of the class vane pump does not work during work, so removing it does not affect the work.

Claims (1)

1. lift range valve mechanism for variable valve, form by control unit of engine, final controlling element, valve transmission group, valve group, the valve transmission group is made up of the variable oil hydraulic pump of pump oil mass, oil duct (4) and oil hydraulic cylinder, and oil hydraulic pump links to each other with oil hydraulic cylinder by oil duct (4), it is characterized in that: oil hydraulic pump adopts the class vane pump, the rotor of class vane pump (17) links to each other with rocking arm (16), and pump case (18) that can move left and right links to each other with pull bar (19).

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