A fully variable valve mechanism for high-power internal combustion engines

Abstract

The utility model belongs to the internal combustion engine technical field relates to a kind of full variable valve mechanism for high-power internal combustion engine, main body structure includes cam piston group, servo piston group, valve piston group and controller, cam piston group working chamber, servo piston group working chamber and valve piston group working chamber are connected by hydraulic oil circuit and form the intercommunication of high-pressure oil circuit, low-pressure oil circuit is connected with high-pressure oil circuit by check valve, compensate high-pressure oil circuit in hydraulic oil leakage, cam piston group cam rotates with internal combustion engine cam, valve piston group valve is opened and closed by high-pressure oil circuit control, servo piston group servo motor servo control adjusts servo piston group working chamber volume, and then by adjusting servo piston group working chamber volume and volume adjustment moment, adjust valve piston group valve lift and phase;It is simple in structure, with high reliability, high efficiency energy saving, compact structure and other advantages, provide new scheme for full variable valve mechanism for high-power internal combustion engine.

Description

Technical fields:

[0001] This utility model belongs to the field of internal combustion engine technology and relates to a fully variable valve mechanism for high-power internal combustion engines, specifically a cam-based hydraulic fully variable valve mechanism for high-power internal combustion engines with volume servo control. Background technology:

[0002] Variable valve timing technology is broadly classified into two categories: camshaft-based variable valve timing and camless variable valve timing. It can meet the requirements of different engine operating conditions, improve fuel efficiency, enhance power performance, and reduce pollutant emissions, demonstrating significant application value. Camless variable valve timing technology offers greater control flexibility; however, its reliability is lower than that of camshaft-based variable valve timing technology. Camshaft-based variable valve timing technology includes mechanical and hydraulic adjustment types. Even if the adjustment device fails, the internal combustion engine can still operate. Hydraulic adjustment, with its compact structure, easily accommodates installation within the limited space of the cylinder head and is currently a popular application. However, existing hydraulic adjustment camshaft-based variable valve timing technologies often employ throttle valve control, resulting in significant throttling losses. For example, Chinese Patent 202411800996.4 discloses a fully variable valve engine system, including a control unit, a crankshaft signal disk, a first crankshaft position sensor, a second crankshaft position sensor, and valves. The control unit is electrically connected to the crankshaft signal disk, the first crankshaft position sensor, the second crankshaft position sensor, and the valves. The first and second crankshaft position sensors are located on opposite sides of the crankshaft signal disk to detect the angular displacement of the crankshaft signal disk when it rotates, generating a first reference signal and a second reference signal respectively. The control method includes: acquiring the first reference signal and the second reference signal during engine operation, and generating... The engine's current operating condition signal is used to determine the target opening and closing angles of the valves. Based on the current operating condition signal, the first reference signal, the second reference signal, the target opening angle, and the target closing angle, the valve opening and closing times are determined. When the valve is open, the actual opening angle is acquired, and when the valve is closed, the actual closing angle is acquired. Based on the relationship between the actual opening angle and the target opening angle, and the relationship between the actual closing angle and the target closing angle, the target opening and closing angles are corrected in real time to ensure that the actual opening angle and the target opening angle are the same.Chinese Patent 202222116191.0 discloses a hydraulic fully variable valve mechanism, which utilizes an actuator with a seating buffer structure. The actuator includes a hydraulic piston, a piston sleeve, a one-way valve, and a clearance compensation mechanism, all disposed within a mounting hole in the variable valve housing. The one-way valve is fixedly disposed on the top of the piston sleeve and connected to a hydraulic oil circuit on the variable valve housing. The hydraulic piston is slidably disposed within the piston sleeve, and the bottom end of the hydraulic piston is fixedly connected to the valve via the clearance compensation mechanism. Several clearance compensation mechanisms are provided at circumferential intervals on the side wall of the piston sleeve. The side wall oil hole is located near the check valve. The top of the hydraulic piston is a buffer cone. The piston sleeve is a cylindrical structure and is vertically positioned. The side wall oil hole is located near the top of the piston sleeve. The top of the buffer cone is a flat surface. The side wall of the buffer cone forms an acute angle with the axis of the hydraulic piston. The acute angle ranges from 5° to 30°. The height of the buffer cone does not exceed the minimum height from the side wall oil hole to the top of the piston sleeve. The clearance compensation mechanism is connected to the hydraulic oil circuit on the variable valve housing. The check valve and the clearance compensation mechanism do not share a hydraulic oil circuit. Chinese Patent 202022285681.4 discloses an electro-hydraulic fully variable valve mechanism based on a valve train cam, comprising a rocker arm with slots at both ends facing inwards. A valve roller's roller is rotatably connected to the front and rear sidewalls of the right slot, and a hydraulic plunger's roller is rotatably connected to the front and rear sidewalls of the left slot. A valve assembly presses against the valve roller, including a valve whose top end directly contacts the valve roller. A valve spring is fitted onto a valve tappet, with its top fixed to the valve and its bottom fixed to the engine cylinder head. A vertically oriented through slot is formed in the rocker arm, and a cam roller is installed in the through slot with its roller rotatably connected to the front and rear sidewalls of the through slot. The axes of the rollers are parallel to each other. A cam presses against the cam roller. The starting point of the cam wrap angle corresponds to the earliest valve opening time, and the ending point of the cam wrap angle corresponds to the latest valve closing time. The cam wrap angle angle corresponds to half of the crankshaft rotation angle experienced from the earliest valve opening time to the latest valve closing time. The cam height corresponds to the maximum valve lift that the variable valve mechanism can achieve. The upper part of the hydraulic plunger is fixedly connected to the roller of the hydraulic plunger. The hydraulic plunger is nested in the inner cavity of the hydraulic cylinder and can move up and down axially along the inner wall of the hydraulic cylinder. The bottom of the hydraulic plunger and the inner cavity of the hydraulic cylinder together form a closed oil chamber with variable volume. An oil hole communicating with the oil chamber is opened on the bottom wall of the hydraulic cylinder. The other end of the oil hole is connected to port a of the three-position three-way solenoid valve through an oil pipe. Port b of the three-position three-way solenoid valve is connected to the high-pressure oil source, and port c of the three-position three-way solenoid valve is connected to the low-pressure oil source.

[0003] Therefore, it is necessary to develop and design a fully variable valve mechanism for high-power internal combustion engines, which can adjust the working chamber volume through a servo piston with flexible and controllable motion trajectory, thereby eliminating the throttling loss problem caused by the throttle valve. Summary of the Invention:

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and to develop and design a fully variable valve mechanism for high-power internal combustion engines, which achieves volume servo adjustment of the high-pressure oil circuit by driving a servo piston with a servo motor.

[0005] To achieve the above objectives, the main structure of the high-power internal combustion engine fully variable valve mechanism of this utility model includes a high-pressure oil circuit and a cam piston group, a servo piston group and a valve piston group installed thereon, as well as a low-pressure oil circuit connected thereto. The servo piston group is connected to the controller, and the low-pressure oil circuit is connected to the high-pressure oil circuit through a one-way valve to compensate for hydraulic oil leakage in the high-pressure oil circuit.

[0006] The main structure of the cam piston assembly includes the cam piston assembly hydraulic cylinder and the cam piston assembly spring and cam piston assembly piston installed inside it, as well as the cam piston assembly cam that can contact the cam piston assembly piston.

[0007] The main structure of the servo piston assembly includes the servo piston assembly hydraulic cylinder and the servo piston assembly piston installed inside it, as well as the servo piston assembly lead screw connected to the servo piston assembly piston and the servo piston assembly servo motor connected to the servo piston assembly lead screw.

[0008] The main structure of the valve piston assembly includes a valve piston assembly hydraulic cylinder and a valve piston assembly piston installed inside it, as well as a valve piston assembly valve connected to the valve piston assembly piston and a valve piston assembly spring installed on the valve piston assembly valve.

[0009] In addition, a servo piston displacement sensor is also installed on the piston of the servo piston assembly, which is connected to the servo piston assembly screw through the servo piston assembly screw nut.

[0010] The lead screw of the servo piston assembly is connected to the servo motor of the servo piston assembly via the servo piston assembly reducer.

[0011] The servo piston assembly servo motor is connected to the controller.

[0012] The working principle of the fully variable valve mechanism for high-power internal combustion engines involved in this utility model is as follows:

[0013] When the cam of the cam piston assembly is in the rising stage, the piston of the cam piston assembly further compresses the cam piston assembly spring, and the volume of the working chamber V1 of the cam piston assembly decreases.

[0014] The pressure in the high-pressure oil circuit rises until it overcomes the pressure of the valve piston assembly spring on the valve piston assembly piston, and then the valve lift of the valve piston assembly gradually increases.

[0015] When the cam of the cam piston assembly is in the descending stage, the piston of the cam piston assembly gradually falls back under the action of the cam piston assembly spring, the volume of the working chamber V1 of the cam piston assembly increases, and the valve of the valve piston assembly gradually decreases under the action of the valve piston assembly spring.

[0016] When the lift and phase of the valve in the valve piston assembly are not adjusted, the servo motor of the servo piston assembly remains in its initial position, and the volume of the working chamber V2 of the servo piston assembly remains unchanged.

[0017] The volume of the working chamber V2 of the servo piston group is adjusted by the servo motor of the servo piston group. By adjusting the volume of the working chamber V2 of the servo piston group and the volume adjustment time, the lift and phase of the valve of the valve piston group are adjusted.

[0018] When the cam of the cam piston assembly malfunctions, the servo piston assembly piston is controlled by the servo motor of the servo piston assembly to move according to the preset displacement curve, thereby driving the valve piston assembly valve to open and close.

[0019] The servo piston group is controlled by a servo motor to move the piston of the servo piston group, which drives the valve of the valve piston group to perform multiple opening and closing actions within one cam rotation cycle of the cam piston group, or to achieve valve seating buffering of the valve piston group.

[0020] The control strategy for the fully variable valve mechanism for high-power internal combustion engines involved in this utility model is adjusted by the controller 4 according to the demand command, timing signal, speed signal, and cam profile information, based on the cam's operating cycle. Specifically, the control strategy includes the following:

[0021] 1. Individual valve lift adjustment strategy

[0022] When the cam of the cam piston group is in the rising stage, and the valve lift of the valve piston group gradually increases, the servo piston group piston displacement is controlled by the servo motor of the servo piston group to decrease or increase the volume of the working chamber V2 of the servo piston group, thereby increasing or decreasing the maximum valve lift of the valve piston group respectively.

[0023] When the cam of the cam piston group is in the descending stage and the valve lift of the valve piston group is gradually rising, the servo piston group piston displacement is controlled by the servo motor of the servo piston group so that the working chamber V2 volume of the servo piston group returns to the initial value.

[0024] 2. Individual valve opening phase adjustment strategy

[0025] When the cam of the cam piston group is in the rising stage and before the valve lift of the valve piston group begins to rise, the servo piston group piston displacement is controlled by the servo motor of the servo piston group to decrease or increase the volume of the working chamber V2 of the servo piston group, thereby advancing or delaying the valve opening phase of the valve piston group respectively.

[0026] During the gradual increase of valve lift in the valve piston assembly, the piston displacement of the servo piston assembly is controlled by the servo motor of the servo piston assembly, so that the working chamber V2 volume of the servo piston assembly returns to the initial value.

[0027] 3. Individual valve closing phase adjustment strategy

[0028] When the cam of the cam piston group is in the descending stage, and the valve lift of the valve piston group gradually decreases, the servo piston group piston displacement is increased or decreased by controlling the servo piston group working chamber V2 volume by controlling the servo piston group servo motor, which advances or delays the valve closing phase of the valve piston group respectively.

[0029] After the valve of the valve piston assembly is closed, the piston displacement of the servo piston assembly is controlled by the servo motor of the servo piston assembly so that the volume of the working chamber V2 of the servo piston assembly returns to the initial value.

[0030] 4. Simultaneous adjustment strategy of valve lift / opening phase

[0031] When the cam of the cam piston group enters the rising stage, the piston displacement of the servo piston group is controlled by the servo motor of the servo piston group to decrease or increase the volume of the working chamber V2 of the servo piston group, thereby increasing or decreasing the maximum lift of the valve of the valve piston group and advancing or delaying the valve opening phase of the valve piston group, respectively.

[0032] As the cam enters the descending phase of the cam piston assembly, and the valve lift of the valve piston assembly gradually decreases, the servo piston assembly's working chamber V2 volume is restored to its initial value by controlling the piston displacement of the servo piston assembly via the servo motor.

[0033] Compared with the prior art, the main structure of this utility model includes a cam piston assembly, a servo piston assembly, a valve piston assembly, and a controller. The working chambers of the cam piston assembly, the servo piston assembly, and the valve piston assembly are connected by a hydraulic oil circuit to form a high-pressure oil circuit. The low-pressure oil circuit is connected to the high-pressure oil circuit through a one-way valve to compensate for hydraulic oil leakage in the high-pressure oil circuit. The cam of the cam piston assembly rotates with the cam of the internal combustion engine. The valve of the valve piston assembly is opened and closed by controlling the high-pressure oil circuit. The servo motor of the servo piston assembly is used to control and adjust the volume of the working chamber of the servo piston assembly. In turn, by adjusting the volume of the working chamber of the servo piston assembly and the volume adjustment time, the lift and phase of the valve of the valve piston assembly are adjusted. Its structure is simple and has the advantages of high reliability, high efficiency and energy saving, and compact structure. It provides a new solution for the fully variable valve mechanism for high-power internal combustion engines. The servo motor drives the servo piston to realize the servo adjustment of the volume of the high-pressure oil circuit, thereby adjusting the valve lift and phase, eliminating the throttling loss caused by the throttle valve. The movement trajectory of the servo piston driven by the servo motor is flexible and controllable. It can also realize multiple opening and closing of the valve and seat buffering in one cam cycle. Attached image description:

[0034] Figure 1 This is a schematic diagram of the main structure principle of this utility model.

[0035] Figure 2 This is a schematic diagram of the control process of this utility model. Detailed implementation method:

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0037] Example 1:

[0038] The main structure of a fully variable valve mechanism for a high-power internal combustion engine involved in this embodiment is as follows: Figure 1 As shown, it includes a cam piston assembly 1, a servo piston assembly 2, a valve piston assembly 3, a controller 4, a high-pressure oil circuit 10, a low-pressure oil circuit 20, and a one-way valve 30; the cam piston assembly 1, the servo piston assembly 2, and the valve piston assembly 3 are respectively connected to the high-pressure oil circuit 10, the servo piston assembly 2 is also connected to the controller 4, the high-pressure oil circuit 10 is also connected to the low-pressure oil circuit 20, and a one-way valve 30 is provided between the two.

[0039] The main structure of cam piston assembly 1 is as follows Figure 1 As shown, it includes a cam piston assembly spring 1.1, a cam piston assembly hydraulic cylinder 1.2, a cam piston assembly piston 1.3, and a cam piston assembly cam 1.4; the cam piston assembly spring 1.1 is disposed inside the cam piston assembly hydraulic cylinder 1.2, one end of the cam piston assembly piston 1.3 is connected to the cam piston assembly spring 1.1, and the other end can extend out of the cam piston assembly hydraulic cylinder 1.2 to contact the cam piston assembly cam 1.4, and the cam piston assembly cam 1.4 is connected to the camshaft of the internal combustion engine and is driven by the internal combustion engine;

[0040] Furthermore, the cam piston assembly hydraulic cylinder 1.2 and the cam piston assembly piston 1.3 form the cam piston assembly working chamber V1, and the cam piston assembly spring 1.1 applies a thrust to the cam piston assembly piston 1.3 so that it presses against the cam piston assembly cam 1.4;

[0041] The main structure of servo piston assembly 2 is as follows Figure 1 As shown, it includes a servo piston assembly hydraulic cylinder 2.1, a servo piston assembly piston 2.2, a servo piston assembly lead screw nut 2.3, a servo piston assembly lead screw 2.4, a servo piston assembly reducer 2.5, a servo piston assembly servo motor 2.6, and a servo piston assembly piston displacement sensor 2.7.

[0042] The servo piston group hydraulic cylinder 2.1 is equipped with a servo piston group piston 2.2. The servo piston group piston 2.2 is connected to the servo piston group screw 2.4 through the servo piston group screw nut 2.3. The servo piston group screw 2.4 is connected to the servo piston group servo motor 2.6 through the servo piston group reducer 2.5. The servo piston group servo motor 2.6 is connected to the controller 4. In addition, the servo piston group piston displacement sensor 2.7 is also installed on the servo piston group piston 2.2.

[0043] Furthermore, the servo piston group hydraulic cylinder 2.1 and the servo piston group piston 2.2 form the servo piston group working chamber V2. The servo piston group piston 2.2 is fixedly connected to the servo piston group lead screw nut 2.3, and the servo piston group lead screw 2.4 is assembled inside the servo piston group lead screw nut 2.3, which can convert the rotational motion of the servo piston group lead screw 2.4 into the linear motion of the servo piston group piston 2.2 and the servo piston group lead screw nut 2.3. The output shaft of the servo piston group reducer 2.5 is fixedly connected to the servo piston group lead screw 2.4, and the input shaft is fixedly connected to the rotor of the servo piston group servo motor 2.6.

[0044] The main structure of valve-piston assembly 3 is as follows Figure 1 As shown, it includes a valve piston assembly hydraulic cylinder 3.1, a valve piston assembly piston 3.2, a valve piston assembly valve 3.3, and a valve piston assembly spring 3.4; the valve piston assembly hydraulic cylinder 3.1 is equipped with a valve piston assembly piston 3.2, the valve piston assembly piston 3.2 is connected to the valve piston assembly valve 3.3, and the valve piston assembly spring 3.4 is installed on the valve piston assembly valve 3.3;

[0045] Furthermore, the valve piston assembly hydraulic cylinder 3.1 and the valve piston assembly piston 3.2 form the valve piston assembly working chamber V3, and the valve piston assembly spring 3.4 applies a restoring force to the valve piston assembly valve 3.3 to restore it to the closed loop state;

[0046] Specifically, the working chamber V1 of the cam piston assembly, the working chamber V2 of the servo piston assembly, and the working chamber V3 of the valve piston assembly are connected by a hydraulic oil circuit to form a high-pressure oil circuit 10. The low-pressure oil circuit 20 is connected to the high-pressure oil circuit 10 through a one-way valve 30 to compensate for hydraulic oil leakage in the high-pressure oil circuit 10.

[0047] The motion states of the cam piston assembly cam 1.4 and valve piston assembly valve 3.3 in this embodiment are obtained from timing signals, speed signals, and cam profile information. Alternatively, a valve piston assembly valve 3.3 displacement sensor can be added to obtain the motion state of the valve piston assembly valve 3.3.

[0048] The servo piston assembly hydraulic cylinder 2.1, the cam piston assembly hydraulic cylinder 1.2, and / or the valve piston assembly hydraulic cylinder 3.1 can be machined as a single unit to improve system integration.

[0049] The servo piston reducer 2.5 is a planetary gear mechanism;

[0050] The servo piston assembly servo motor 2.6 integrates a motor rotor position sensor, which, together with the displacement signal of the servo piston assembly piston 2.2 collected by the servo piston assembly piston displacement sensor 2.7, performs closed-loop control on the position of the servo piston assembly piston 2.2, thereby controlling the volume of the working chamber V2 of the servo piston assembly.

[0051] Example 2:

[0052] The basic control flow of a fully variable valve timing control strategy for a high-power internal combustion engine involved in this embodiment is as follows: Figure 2 As shown:

[0053] 1. Controller 4 acquires the required valve lift, phase adjustment amount, camshaft timing signal, and speed signal;

[0054] 2. Determine the required adjustment mode based on the required valve lift and phase adjustment amount;

[0055] 3. Calculate the motion curve of the servo piston for this cam cycle based on the adjustment mode;

[0056] 4. Calculate and output the servo motor control signal based on the motion curve of the servo piston in this cam cycle;

[0057] 5. After the current cam cycle ends, process 1 will be executed again.

Claims

1. A fully variable valve mechanism for a high-power internal combustion engine, characterized in that, The main structure includes a high-pressure oil circuit and a cam piston assembly, a servo piston assembly, and a valve piston assembly mounted thereon, as well as a low-pressure oil circuit connected thereto.

2. The full variable valve actuating mechanism for a large output internal combustion engine according to claim 1, characterized in that, The main structure of the cam piston assembly includes the cam piston assembly hydraulic cylinder and the cam piston assembly spring and cam piston assembly piston installed inside it, as well as the cam piston assembly cam that can contact the cam piston assembly piston.

3. The full variable valve mechanism for a large output internal combustion engine according to claim 2, characterized in that, The main structure of the servo piston assembly includes a servo piston assembly hydraulic cylinder and a servo piston assembly piston installed inside it, as well as a servo piston assembly lead screw connected to the servo piston assembly piston and a servo piston assembly servo motor connected to the servo piston assembly lead screw.

4. The full variable valve mechanism for a large output internal combustion engine according to claim 3, characterized in that, The main structure of the valve piston assembly includes a valve piston assembly hydraulic cylinder and a valve piston assembly piston installed inside it, as well as valve piston assembly valves connected to the valve piston assembly pistons and valve piston assembly springs installed on the valve piston assembly valves.

5. The fully variable valve mechanism for high-power internal combustion engines according to claim 3, characterized in that, The servo piston assembly is also equipped with a servo piston displacement sensor.

6. The fully variable valve mechanism for high-power internal combustion engines according to claim 3, characterized in that, The lead screw of the servo piston assembly is connected to the servo motor of the servo piston assembly through the servo piston assembly reducer.

7. The fully variable valve mechanism for high-power internal combustion engines according to claim 3, characterized in that, The servo piston assembly servo motor is connected to the controller.

8. The fully variable valve mechanism for high-power internal combustion engines according to claim 5, characterized in that, The piston of the servo piston assembly is connected to the servo piston assembly screw via the servo piston assembly screw nut.

9. The fully variable valve mechanism for a high-power internal combustion engine according to any one of claims 1-8, characterized in that, The low-pressure oil circuit is connected to the high-pressure oil circuit via a check valve.

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