CN2546635Y - Variable air door lift mechanism - Google Patents

Abstract

The new variable valve lift mechanism includes a cylinder head, a cam, a camshaft driving the cam to rotate, a valve tappet driven by the cam and a valve controlled by the tappet. There is a high-speed cam and two low-speed cams symmetrically located on both sides of the high-speed cam on the camshaft. A return spring is installed between the outer boss of the small tappet and the inner boss of the big tappet, the plunger of the small tappet is located in the hydraulic chamber of the big tappet, and the small tappet is in contact with the high-speed cam; the plunger of the big tappet is located In the tappet running track of the cylinder head, the two ends of the large tappet are respectively connected to two valves, and the large tappet is in contact with the two low-speed cams; the hydraulic chamber is connected to the decompression chamber in the cylinder head through the hydraulic oil passage, and the hydraulic oil passage is installed There is a solenoid valve. The advantage of this structure is that different cams are used to drive the valve tappets at high speed and low speed to change the valve timing and valve lift, so that both the low speed performance and high speed performance of the engine can be optimized and improved.

Description

New variable valve lift mechanism

Technical field

The utility model belongs to the technical field of an automobile gas distribution mechanism, in particular to a novel variable valve lift mechanism.

technical background

The variable valve timing technology has been paid more and more attention by the world's major automobile manufacturers due to its outstanding advantages of effectively improving the power, economy and exhaust emissions of the engine at different speeds and loads. The United States, Japan, Europe and other countries began to engage in the research work of variable valve timing technology as early as the 1980s. In addition, the rapid development of today's electronic technology has promoted the development of variable valve timing technology from the research stage to the practical stage. There are already engine products with variable valve timing technology on the market now. The relative rotation angle of the intake/exhaust camshaft is improved, and the intake/exhaust camshaft is driven to run normally.

The technology closest to the present invention mainly contains two kinds, one is to utilize the adjustable hydraulic lifter to realize the variable valve lift, and the key of this technology is the adjustable hydraulic lifter. The working principle of this technology is as follows: when the engine is running at low speed, the two parts of the tappet are separated by hydraulic pressure and the coupling pin. At this time, the high-speed cam fails, and the middle low-speed cam is used to control the operation of the valve. When running at high speed, the two parts can be connected by hydraulic pressure and the connecting pin, and the opening of the valve is controlled by the high-speed cams on both sides. This technology mainly has the following shortcoming: 1, the adjustable hydraulic tappet is very complicated. 2. Each valve needs three cams to be driven, and the camshaft structure is complex, which is not conducive to the application of multi-valve technology. 3. The hydraulic control oil passage in the cylinder head is very complicated.

The second technology close to the present invention is an electronically controlled hydraulic tappet variable valve mechanism. When the solenoid valve is closed, the cam pushes the first tappet. Since the hydraulic oil in the tappet chamber cannot overflow, the oil pressure pushes the first tappet. Two tappets make the valve open late or close early. The structure of this mechanism is relatively simple, but the response speed is not high enough, and there are two-stage tappets, which increase the height and overall size of the cylinder head.

The utility model aims at the above-mentioned shortcomings existing in the prior art, and invents a valve tappet driven by different cams at high speed and low speed to change the gas distribution phase and valve lift, so that the low-speed performance and high-speed performance of the engine are improved. A novel variable valve lift mechanism which can be optimized and improved.

Contents of the invention

The technical scheme of the utility model is as follows:

The new variable valve lift mechanism includes a cylinder head, a cam, a camshaft driving the cam to rotate, a valve tappet driven by the cam or a valve controlled by the tappet. There is a high-speed cam and two low-speed cams symmetrically located on both sides of the high-speed cam on the camshaft. The valve tappet has a large tappet and a small tappet. A return spring is installed between the outer edge boss of the small tappet and the inner edge boss of the big tappet, the small tappet plunger is located in the hydraulic cavity of the big tappet, and the small tappet contacts and cooperates with the high-speed cam. The plunger of the big tappet is located in the tappet running track of the cylinder head, and the two ends of the big tappet are respectively connected with two valves through a valve seat and a push rod, and the big tappet contacts and cooperates with two low-speed cams. The hydraulic chamber communicates with the decompression chamber in the cylinder head through the hydraulic oil passage, and the decompression plunger and spring are installed in the decompression chamber, and the solenoid valve is installed on the hydraulic oil passage. This mechanism uses two low-speed cams and one high-speed cam to drive the same valve lifter. At high speed, the solenoid valve closes the hydraulic channel, and the high-speed cam drives the valve lifter; at low speed, the solenoid valve opens the hydraulic channel, and the high-speed cam Failed, the valve lifters are driven by the two low speed cams. Realize that one valve tappet controls the operation of two valves at the same time.

There are two arrangements of the camshaft and the valve lifters, one is the parallel arrangement of the camshaft and the large and small lifters, and the other is a vertical arrangement.

The advantages of this institution are:

1 According to the requirements of gasoline engine performance optimization, high-speed cams and low-speed cams are used to control the drive of the valves at high and low speeds, which can reduce the pumping loss of the engine, speed up the intake speed, improve the quality of the mixed gas, increase the charging efficiency, and finally improve the engine. The combustion process significantly improves the power, economy, and emissions compared with traditional gasoline engines.

2. The use of three cams to simultaneously control two valves saves space and facilitates the application and arrangement of multi-valve technology

3. Adopting the structure type with the vertical configuration of the camshaft and the valve lifter, it has found a way out for the single overhead camshaft valve train type engine to adopt VVT technology

4 The principle, structure and control system are very simple and feasible.

Description of drawings

Fig. 1 is a structural schematic diagram of a variable valve lift mechanism in which the camshaft and the valve lifter are arranged in parallel;

Fig. 2 is A-A sectional view of Fig. 1;

Fig. 3 is a structural schematic diagram of a variable valve lift mechanism in which the camshaft and the valve lifter are vertically arranged;

Fig. 4 is A-A sectional view of Fig. 3;

Fig. 5 is the working principle diagram of this mechanism when running at a low speed;

Fig. 6 is A-A sectional view of Fig. 5;

Fig. 7 is the working principle diagram of this mechanism when running at high speed;

Fig. 8 is a cross-sectional view along line A-A of Fig. 7 .

Detailed ways

The structure of this mechanism is referring to Fig. 1-4, and this mechanism is made of camshaft 3, high-speed cam 2, two low-speed cams 1a and 1b, small tappet 4, large tappet 5, two valves 10 and cylinder head 8. The high-speed cam 2 is located in the middle of the camshaft 3 and is in contact with the small tappet 4. The two low-speed cams 1a and 1b are located symmetrically on both sides of the high-speed cam 2 and are in contact with the large tappet 5 . The small tappet 4 is located in the large tappet 5, and a return spring 12 is arranged between its outer edge boss and the inner edge boss of the big tappet. The small tappet plunger 11 is located in the hydraulic cavity 6 of the large tappet 5 . The hydraulic chamber 6 communicates with the decompression chamber 18 in the cylinder head 8 through the hydraulic oil passage 7 . The decompression plunger 16 and the spring 17 are installed in the decompression chamber 18 , and the solenoid valve 15 is installed on the hydraulic oil passage 7 . The two ends of the big tappet 5 are symmetrically connected with two valves 10 through valve seats and push rods. The large tappet plunger 13 is positioned in the tappet running track 14 of the cylinder head, and the tappet running track 14 has a vent hole 9 to communicate with the atmosphere.

The camshaft 4 and the valve tappets of this mechanism have two arrangements, one is that the camshaft 4 is arranged in parallel with the large and small tappets, see Figures 1 and 2; the other is a vertical arrangement, see Figures 3 and 4.

The mechanism works as follows:

When the engine is running at low speed, see Figures 5 and 6, the solenoid valve 15 is opened, the high-speed cam 2 pushes the small tappet 4 to run downward, the hydraulic oil overflows from the hydraulic chamber 6 to the hydraulic oil channel 7, and pushes the decompression plunger 16 Moving to the right, the oil pressure is small, and the force acting on the bottom of the large tappet 5 is very small, and the valve 10 cannot be opened. At the same time, with the downward movement of the small tappet 4, the low-speed cams 1a and 1b on both sides of the high-speed cam 2 The large tappet 5 is directly driven, and under the direct drive of the low-speed cams 1a and 1b, the valve tappet moves downward and opens the valve 10.

When the engine is running at high speed, see Figures 7 and 8, the solenoid valve 15 is closed, and since the hydraulic oil cannot overflow in the hydraulic chamber 6, driven by the high-speed cam 2, the oil pressure increases and pushes the large tappet 5 to open the valve 10.

Claims (4)

1. A new type of variable valve lift mechanism, including a cylinder head, a cam, a camshaft that drives the cam to rotate, a valve tappet driven by the cam, and a valve controlled by the tappet. It is characterized in that there is a high-speed cam on the camshaft and Two low-speed cams symmetrically located on both sides of the high-speed cam; the tappets have a large tappet and a small tappet, and a return spring is installed between the outer boss of the small tappet and the inner boss of the big tappet, and the plunger of the small tappet is located In the hydraulic chamber of the big tappet, the small tappet is in contact with the high-speed cam; the plunger of the big tappet is located in the tappet running track of the cylinder head, and the two ends of the big tappet are respectively connected to two valves, and the big tappet is connected to the two low-speed cams. Contact fit; the hydraulic chamber communicates with the decompression chamber in the cylinder head through the hydraulic oil passage, the decompression chamber is equipped with a decompression plunger and a spring, and the hydraulic oil passage is provided with a solenoid valve. 2. The novel variable valve lift mechanism according to claim 1, characterized in that there is a ventilation hole connected to the atmosphere in the tappet running track. 3. The novel variable valve lift mechanism according to claim 1 or 2, characterized in that the camshaft is arranged in parallel with the large and small tappets. 4. The novel variable valve lift mechanism according to claim 1 or 2, characterized in that the camshaft and the large and small tappets are vertically arranged.

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