A hydraulic valve lift curve switching mechanism

Abstract

The present invention provides a hydraulic valve lift curve switching mechanism, which is driven by a cam drive mechanism; a spool valve is connected to a pressure-adjustable hydraulic chamber through a first spring; a first active hydraulic cylinder is connected to the pressure-adjustable hydraulic chamber through a first oil passage, a second active hydraulic cylinder is connected to the pressure-adjustable hydraulic chamber through a second oil passage, and the pressure-adjustable hydraulic chamber is connected to a first driven hydraulic cylinder through a third oil passage; the pressure-adjustable hydraulic chamber is connected to a second driven hydraulic cylinder through a fourth oil passage, and the second driven hydraulic cylinder is in contact with a valve through a driven plunger. A driven piston is arranged in the first driven hydraulic cylinder, and the driven piston is connected to the inside of the first driven hydraulic cylinder through a second spring; the spool valve is provided with a passage group for communicating the active hydraulic cylinder and the driven hydraulic cylinder. The present invention switches the valve lift curve according to the operating conditions of the engine, further improving the economy and power performance of the engine.

Description

Technical Field

[0001] The present invention belongs to the technical field of engines, and in particular relates to a hydraulic valve lift curve switching mechanism. Background Art

[0002] The base number of automobiles in China is huge, consuming a large amount of fossil fuels and emitting a large amount of carbon dioxide. Developing energy-saving automobiles is one of the important measures to reduce carbon dioxide emissions, and improving engine efficiency to further enhance the energy-saving level of automobiles. The vehicle power system also needs to have good power performance and respond quickly to the driver's commands; under partial load, it is necessary to reduce the engine valve lift curve to improve combustion and economy, while under high load conditions, it is necessary to increase the engine valve lift curve to increase the intake air volume and improve power performance. However, the conventional mechanical valve cam valve train installed in traditional engines has a constant valve lift curve and cannot switch the valve lift curve according to the operating conditions. Therefore, it is difficult for traditional engines to achieve the best economy and power performance at the same time; therefore, a hydraulic valve lift curve switching mechanism is of great significance for improving the economy and power performance of engines. Summary of the Invention

[0003] In view of this, the present invention aims to provide a hydraulic valve lift curve switching mechanism that can switch the valve lift curve according to the engine operating conditions, further improving the economy and power performance of the engine.

[0004] To achieve the above object, the technical solution of the present invention is realized as follows:

[0005] A cam drive mechanism, including a first cam, a second cam, a first active piston, a second active piston, a first active hydraulic cylinder, a second active hydraulic cylinder, a first oil passage, and a second oil passage; a pressure-adjustable hydraulic chamber is provided inside the hydraulic housing, and the pressure-adjustable hydraulic chamber is communicated with the first active hydraulic cylinder through the first oil passage and with the second active hydraulic cylinder through the second oil passage; the first active piston in the first active hydraulic cylinder is in contact with the first cam; the second active piston in the second active hydraulic cylinder is in contact with the second cam.

[0006] Further, the radius of the protruding part of the first cam is greater than the radius of the protruding part of the second cam, so that the first cam and the second cam have different lift curves.

[0007] Further, the structural dimensions of the first active piston and the second active piston are the same.

[0008] A hydraulic valve lift curve switching mechanism is driven by a cam drive mechanism; a spool valve, a first driven hydraulic cylinder, and a second driven hydraulic cylinder are further provided inside the housing, the spool valve is provided inside the pressure-adjustable hydraulic chamber, and the spool valve is connected to the pressure-adjustable hydraulic chamber through a first spring;

[0009] The first active hydraulic cylinder is connected to the pressure-adjustable hydraulic chamber through the first oil passage, the second active hydraulic cylinder is connected to the pressure-adjustable hydraulic chamber through the second oil passage, and the pressure-adjustable hydraulic chamber is connected to the first driven hydraulic cylinder through the third oil passage; the pressure-adjustable hydraulic chamber is connected to the second driven hydraulic cylinder through the fourth oil passage, and the second driven hydraulic cylinder is in contact with the valve through a driven plunger. A driven piston is provided in the first driven hydraulic cylinder, and the driven piston is connected to the inside of the first driven hydraulic cylinder through a second spring;

[0010] The spool valve is provided with a passage group that connects the active hydraulic cylinder and the driven hydraulic cylinder.

[0011] Further, annular grooves are provided on the surface of the spool valve, and the plurality of annular grooves form the passage group. The passage group includes a first passage, a second passage, and a third passage.

[0012] Further, under the action of the pressure-adjustable hydraulic chamber, the spool valve can move up and down.

[0013] Further, when the spool valve is in the top position of the pressure-adjustable hydraulic chamber; the first oil passage is communicated with the fourth oil passage through the second passage, and the second oil passage is communicated with the third oil passage through the third passage;

[0014] When the spool valve is in the bottom position of the pressure-adjustable hydraulic chamber, the first oil passage is communicated with the third oil passage through the first passage, and the second oil passage is communicated with the fourth oil passage through the second passage.

[0015] Further, the lift curves of the valve driven by the first cam and the second cam are also different.

[0016] Further, during the switching process of the spool valve, the lift of the first cam and the second cam is zero.

[0017] Compared with the prior art, the hydraulic valve lift curve switching mechanism of the present invention has the following advantages:

[0018] (1) The hydraulic valve lift curve switching mechanism of the present invention can quickly complete the valve lift curve switching during the period when the valve is closed during the continuous operation of the engine;

[0019] (2) The hydraulic valve lift curve switching mechanism of the present invention can realize different valve lift curve combinations by respectively replacing the first cam or the second cam;

[0020] (3) The hydraulic valve lift curve switching mechanism of the present invention drives the valve by a cam mechanism under different valve lift curves, avoiding the problem that the valve cannot be opened to the maximum lift at high engine speeds. Description of the Drawings

[0021] The accompanying drawings, which form a part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0022] Figure 1 FIG. 4 is a schematic diagram of Embodiment 1 of a hydraulic valve lift curve switching mechanism according to an embodiment of the present invention;

[0023] Figure 2 FIG. 8 is a schematic diagram of Embodiment 2 of a hydraulic valve lift curve switching mechanism according to an embodiment of the present invention.

[0024] Figure 3 FIG. 12 is a schematic diagram of the switching process of two valve curves according to an embodiment of the present invention.

[0025] Description of reference numerals:

[0026] 1. Hydraulic housing; 2. First cam; 3. Second cam; 4. First active piston; 5. First active hydraulic cylinder; 6. Second active piston; 7. Second active hydraulic cylinder; 8. Pressure-adjustable hydraulic chamber; 9. Slide valve; 10. First oil passage; 11. Second oil passage; 12. First spring; 13. Third oil passage; 14. First driven hydraulic cylinder; 15. Driven piston; 16. Second spring; 17. Fourth oil passage; 18. Second driven hydraulic cylinder; 19. Driven plunger; 20. Valve; 21. Channel group; 211. First channel; 212. Second channel; 213. Third channel. Detailed implementation manners

[0027] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0028] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0029] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0031] A cam drive mechanism, such as Figure 1 and Figure 2 As shown, it includes a first cam 2, a second cam 3, a first active piston 4, a second active piston 6, a first active hydraulic cylinder 5, a second active hydraulic cylinder 7, a first oil passage 10, and a second oil passage 11; a pressure-adjustable hydraulic chamber 8 is provided inside a hydraulic housing 1, and the pressure-adjustable hydraulic chamber 8 is communicated with the first active hydraulic cylinder 5 through the first oil passage 10 and communicated with the second active hydraulic cylinder 7 through the second oil passage 11; the first active piston 4 inside the first active hydraulic cylinder 5 is in contact with the first cam 2; the second active piston 6 inside the second active hydraulic cylinder 7 is in contact with the second cam 3.

[0032] Preferably, the radius of the protruding part of the first cam 2 is greater than the radius of the protruding part of the second cam 3, so that the first cam 2 and the second cam 3 have different lift curves.

[0033] Preferably, the structural dimensions of the first active piston 4 and the second active piston 6 are the same.

[0034] A hydraulic valve 20 lift curve switching mechanism is driven by a cam drive mechanism; a spool valve 9, a first driven hydraulic cylinder 14, and a second driven hydraulic cylinder 18 are further provided inside the housing, the spool valve 9 is provided inside the pressure-adjustable hydraulic chamber 8, and the spool valve 9 is connected to the pressure-adjustable hydraulic chamber 8 through a first spring 12;

[0035] The first active hydraulic cylinder 5 is connected to the pressure-adjustable hydraulic chamber 8 through the first oil passage 10, the second active hydraulic cylinder 7 is connected to the pressure-adjustable hydraulic chamber 8 through the second oil passage 11, the pressure-adjustable hydraulic chamber 8 is connected to the first driven hydraulic cylinder 14 through a third oil passage 13; the pressure-adjustable hydraulic chamber 8 is connected to the second driven hydraulic cylinder 18 through a fourth oil passage 17, and the second driven hydraulic cylinder 18 is in contact with the valve 20 through a driven plunger 19. A driven piston 15 is provided inside the first driven hydraulic cylinder 14, and the driven piston 15 is internally connected to the first driven hydraulic cylinder 14 through a second spring 16;

[0036] The spool valve 9 is provided with a passage group for communicating the active hydraulic cylinder and the driven hydraulic cylinder.

[0037] Preferably, an annular groove is provided on the surface of the spool valve 9, and the plurality of annular grooves form a passage group, and the passage group includes a first passage, a second passage, and a third passage.

[0038] Preferably, under the action of the pressure-adjustable hydraulic chamber, the spool valve 9 can move up and down.

[0039] Embodiment 1

[0040] Preferably, the pressure of the pressure-adjustable hydraulic chamber 8 is low, and the spool valve 9 is in the top position under the action of the first spring 12; the first oil passage 10 is communicated with the fourth oil passage 17 through the second passage, and the second oil passage 11 is communicated with the third oil passage 13 through the third passage; the first active hydraulic cylinder 5 is communicated with the second driven hydraulic cylinder 18 through the first oil passage 10 and the fourth oil passage 17, and the first cam 2 drives the valve 20; at the same time, the second active hydraulic cylinder 7 is communicated with the first driven hydraulic cylinder 14 through the second oil passage 11 and the third oil passage 13, and the second cam 3 drives the driven piston 15;

[0041] Embodiment 2

[0042] The pressure of the pressure-adjustable hydraulic chamber 8 is high, and the spool valve 9 is in the bottom position by overcoming the action of the first spring 12. The first oil passage 10 is communicated with the third oil passage 13 through the first passage, and the second oil passage 11 is communicated with the fourth oil passage 17 through the second passage; the second active hydraulic cylinder 7 is communicated with the second driven hydraulic cylinder 18 through the second oil passage 11 and the fourth oil passage 17, and the second cam 3 drives the valve 20; at the same time, the first active hydraulic cylinder 5 is communicated with the first driven hydraulic cylinder 14 through the first oil passage 10 and the third oil passage 13, and the first cam 2 drives the driven piston 15.

[0043] Preferably, during the switching process of the spool valve 9, the lift of both the first cam 2 and the second cam 3 is zero. By changing the pressure of the pressure-adjustable hydraulic chamber 8 and switching the position of the spool valve 9, the lift curve of the valve 20 can be switched.

[0044] Preferably, the lift curves of the first cam 2 and the second cam 3 for driving the valve 20 are also different. As Figure 3 shown, during the continuous operation of the engine, the lift curve of the valve 20 is switched.

[0045] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hydraulic valve lift curve switching mechanism, characterized in that: It includes a hydraulic housing, and a cam drive mechanism is arranged in the hydraulic housing. The cam drive mechanism includes a first cam, a second cam, a first active piston, a second active piston, a first active hydraulic cylinder, a second active hydraulic cylinder, a first oil passage and a second oil passage; a pressure-adjustable hydraulic chamber is arranged in the hydraulic housing, and the pressure-adjustable hydraulic chamber is communicated with the first active hydraulic cylinder through the first oil passage and with the second active hydraulic cylinder through the second oil passage; the first active piston in the first active hydraulic cylinder is in contact with the first cam; the second active piston in the second active hydraulic cylinder is in contact with the second cam; A spool valve, a first driven hydraulic cylinder and a second driven hydraulic cylinder are further arranged in the hydraulic housing, and the spool valve is arranged in the pressure-adjustable hydraulic chamber, and the spool valve is connected to the pressure-adjustable hydraulic chamber through a first spring; The first active hydraulic cylinder is connected to the pressure-adjustable hydraulic chamber through the first oil passage, the second active hydraulic cylinder is connected to the pressure-adjustable hydraulic chamber through the second oil passage, and the pressure-adjustable hydraulic chamber is connected to the first driven hydraulic cylinder through a third oil passage; the pressure-adjustable hydraulic chamber is connected to the second driven hydraulic cylinder through a fourth oil passage, and the second driven hydraulic cylinder is in contact with the valve through a driven plunger. A driven piston is arranged in the first driven hydraulic cylinder, and the driven piston is connected to the inside of the first driven hydraulic cylinder through a second spring; The spool valve is provided with a passage group for communicating the active hydraulic cylinder and the driven hydraulic cylinder; Annular grooves are arranged on the surface of the spool valve, and the plurality of annular grooves form the passage group. The passage group includes a first passage, a second passage and a third passage; When the spool valve is in the top position of the pressure-adjustable hydraulic chamber; the first oil passage is communicated with the fourth oil passage through the second passage, and the second oil passage is communicated with the third oil passage through the third passage; When the spool valve is in the bottom position of the pressure-adjustable hydraulic chamber, the first oil passage is communicated with the third oil passage through the first passage, and the second oil passage is communicated with the fourth oil passage through the second passage.

2. A hydraulic valve lift curve switching mechanism according to claim 1, characterized in that: The radius of the protruding part of the first cam is greater than the radius of the protruding part of the second cam, so that the first cam and the second cam have different lift curves.

3. A hydraulic valve lift curve switching mechanism according to claim 1, characterized in that: The structural dimensions of the first active piston and the second active piston are the same.

4. A hydraulic valve lift curve switching mechanism according to claim 1, characterized in that: The spool valve can move up and down under the action of the pressure-adjustable hydraulic chamber.

5. A hydraulic valve lift curve switching mechanism according to claim 1, characterized in that: The lift curves of the first cam and the second cam for driving the valve are also different.

6. A hydraulic valve lift curve switching mechanism according to claim 1, characterized in that: During the switching process of the spool valve, the lifts of the first cam and the second cam are both zero.

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