Variable valve seating buffer mechanism and control method thereof

Abstract

The invention provides a variable valve seating buffer mechanism and a control method thereof, solves the problem that a traditional fixed valve mechanism cannot be adjusted according to working condition requirements or actual requirements, and adopts the main scheme that the variable valve seating buffer mechanism comprises a cylinder cover and a valve, the oil channel is communicated to an oil pan outside the cylinder cover through an oil discharge hole, the air valve is connected with the tail end of the oil channel and returns through an air valve spring, a sliding valve is further arranged at the position, corresponding to the oil discharge hole, of the cylinder cover, at least one oil outlet hole is formed in the sliding valve, and the oil outlet hole and the oil discharge hole are the same in diameter and direction. An electromagnet is further fixed to the position, corresponding to the top of the sliding valve, of the air cylinder cover, the electromagnet is wrapped by an electromagnetic coil so as to be electrically connected with an external ECU, after the external ECU controls electrification, a valve element in the sliding valve can slide in the radial direction perpendicular to the oil discharge hole under the action of the electromagnetic coil, and connection and disconnection of the oil outlet hole and the oil discharge hole are achieved.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and in particular to a variable valve seating buffer mechanism and its control method. Background Technology

[0002] The internal combustion engine is the prime mover with the highest thermal efficiency and the largest power per unit volume and weight, and its applications are very wide. However, with the increasing depletion of fossil fuels and the continuous deterioration of environmental resources, internal combustion engines need to meet more stringent emission regulations and fuel consumption requirements. Traditional internal combustion engines use fixed-profile cams to drive valves, which cannot guarantee that emissions and fuel consumption will be optimal at all operating conditions. Therefore, most new internal combustion engines adopt variable valve timing technology to optimize emissions and reduce fuel consumption.

[0003] Variable valve timing technology is mainly divided into cam-based variable valve timing and camless valve timing. Cam-based variable valve timing is reliable and has a fast response speed, but because it retains the cam, its valves are only relatively variable and cannot be arbitrarily variable; camless valve timing, on the other hand, can arbitrarily change the valve timing, lift, and duration.

[0004] Depending on the driving method, camless valve timing technology can be categorized into several types, including electromagnetic drive, electric motor drive, electro-hydraulic drive, and electro-hydraulic drive. Compared to the high energy consumption of electromagnetic drives, the complex systems of electric motor drives, and the low response speed of electro-hydraulic drives, camless valve timing systems are relatively simpler and easier to control. However, electro-hydraulic camless valve timing technology suffers from drawbacks such as rapid valve lift and high impact force when the valve reaches its maximum lift and sets, thus necessitating the design of a buffer mechanism. Common buffering solutions include spring buffers and damping orifice buffers, but spring buffers have slow response speeds, while damping orifices, especially small-sized ones, present manufacturing difficulties. Therefore, electro-hydraulic variable valve systems with reliable buffering capabilities represent a future research direction. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the existing technology. The present invention proposes a variable valve seating buffer mechanism and its control method. By controlling the up and down displacement of the slide valve, the flow cross-sectional area of ​​the oil drain hole is changed, thereby changing the return oil flow rate and the valve seating speed, thereby correcting the valve seating buffer curve.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a variable valve seating buffer mechanism, including a cylinder head and a valve. An oil passage is provided in the cylinder head, and the oil passage is connected to the oil pan outside the cylinder head through an oil drain hole. The valve is connected to the end of the oil passage and returns to its original position by a valve spring. A spool valve is also provided in the cylinder head corresponding to the oil drain hole. The spool valve has at least one oil outlet hole, which is the same diameter and direction as the oil drain hole. An electromagnet is also fixed in the cylinder head corresponding to the top of the spool valve. The electromagnet is covered with an electromagnetic coil to be electrically connected to an external ECU. After the external ECU controls the power supply, the valve core in the spool valve can slide radially perpendicular to the oil drain hole under the action of the electromagnetic coil, thereby realizing the opening and closing of the oil outlet hole and the oil drain hole.

[0007] Furthermore, a valve cavity is provided inside the valve body, and the valve core inside the slide valve can slide up and down within the valve cavity.

[0008] The control method for the variable valve seating buffer mechanism described above includes the following steps: S1. Set the valve displacement pulse spectrum based on rotational speed and load; S2. Calibrate the valve displacement pulse spectrum based on the actual operating points and conditions of the engine test bench; S3. Subtract the opening value output by the calibrated pulse spectrum in S2 from the actual opening value finally obtained by the external actuator; S4. The difference in S3, after PID adjustment, is added to the feedforward value of the opening degree and converted into a current value through the characteristic curve of the slide valve assembly. This current value is then used to synchronously drive the slide valve to move to the set value, thus achieving a closed-loop opening degree.

[0009] Furthermore, the operating conditions in step S2 include oil pressure and oil temperature.

[0010] Furthermore, a current closed loop is added inside the opening closed loop to ensure accurate control current.

[0011] Compared with the prior art, the beneficial effects of the present invention include: (1) The spool valve assembly in the hydraulic control mechanism leaks oil, thereby enabling variable valve timing; (2) Adjust the valve seating buffer speed in a timely manner according to the working conditions and correct the valve seating speed curve. (3) Add opening degree closed loop and current closed loop to achieve precise control. Attached Figure Description

[0012] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts. Wherein: Figure 1 The schematic diagram shows a schematic representation of a buffer mechanism structure according to an embodiment of the present invention; Figure 2 The flowchart of the electronic control strategy control method proposed according to an embodiment of the present invention is shown schematically.

[0013] The following are the labels in the diagram: 1. Electromagnetic coil; 2. Electromagnet; 3. Oil passage; 4. Cylinder head; 5. Valve spring; 6. Valve; 7. Spool valve; 8. Oil outlet; 9. ECU; 10. Oil pan; 11. Valve chamber. Detailed Implementation

[0014] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0015] According to one embodiment of the present invention, Figures 1-2 As shown.

[0016] For buffer mechanisms, such as Figure 1 As shown in this embodiment, specifically, a variable valve 6 seating buffer mechanism includes a cylinder head 4 and a valve 6. An oil passage 3 is provided inside the cylinder head 4. The oil passage 3 is connected to the oil pan 10 outside the cylinder head 4 through an oil drain hole. The valve 6 is connected to the end of the oil passage 3 and returns to its original position through a valve 6 spring 5. A slide valve 7 is also provided on the cylinder head 4 at the position corresponding to the oil drain hole. At least one oil outlet hole 8 is provided on the slide valve 7. The oil outlet hole 8 is of the same diameter and direction as the oil drain hole. An electromagnet 2 is also fixed on the top of the slide valve 7 on the cylinder head 4. The electromagnet 2 is covered with an electromagnetic coil 1 to be electrically connected to an external ECU 9. After the external ECU 9 controls the power supply, the valve core inside the slide valve 7 can slide radially perpendicular to the oil drain hole under the action of the electromagnetic coil 1, realizing the opening and closing of the oil outlet hole 8 and the oil drain hole.

[0017] As can be seen, through the above structure, this solution eliminates the traditional solenoid valve on the basis of the electro-hydraulic solution and sets a displacement controller at the oil drain hole, including a slide valve 7, a solenoid coil 1, an electromagnet 2, etc. The slide valve 7 and the valve cavity 11 on the cylinder head form a pair. In addition, a through hole (oil outlet hole 8) is set on the slide valve 7, which connects the oil drain hole to the return oil. By controlling the up and down displacement of the slide valve 7, the flow cross-sectional area of ​​the oil outlet hole 8 of the oil drain hole is changed, thereby changing the return oil flow rate and the valve 6 seat speed, thereby correcting the valve 6 seat buffer curve.

[0018] For the electronic control strategy, the control method includes the following steps: S1. Set the displacement pulse spectrum of slide valve 7 based on rotational speed and load; S2. Calibrate the displacement pulse spectrum of slide valve 7 according to the actual operating conditions and operating points of the engine test bench; S3. Subtract the opening value output by the calibrated pulse spectrum in S2 from the actual opening value finally obtained by the external actuator; S4. The difference in S3 and the PID adjustment are added to the feedforward value of the opening degree and converted into a current value through the characteristic curve of the slide valve 7 component. This current value is then used to synchronously drive the slide valve 7 to move to the set value, thus achieving a closed-loop opening degree.

[0019] It should be noted that this scheme is based on an electro-hydraulic variable valve 6 control mechanism. The electro-hydraulic variable valve 6 control mechanism is driven by hydraulic oil in the oil passage 3. First, the hydraulic oil pushes the valve 6 to its maximum lift. When the required lift is reached, the oil outlet 8 is opened, and the lift no longer increases. In this way, the valve 6 lift is changed, and the valve 6 closing timing is changed.

[0020] Control logic such as Figure 2 In the electronic control strategy, the displacement (i.e., opening degree) pulse spectrum of the spool valve 7 is set based on the speed and load. According to the actual operating conditions and operating points of the engine test bench (such as oil pressure and oil temperature as correction inputs), the displacement pulse spectrum of the spool valve 7 is calibrated. The opening degree value output by the calibrated pulse spectrum is subtracted from the actual opening degree obtained by the actuator. This difference, after PID adjustment, plus the feedforward value of the opening degree, is converted into a current value through the characteristic curve of the spool valve 7 couple to drive the spool valve 7 to move to the set value to achieve the opening degree closed loop. It should be noted that a current closed loop is added inside the opening degree closed loop to ensure the accuracy of the control current, which further ensures the accuracy and consistency of the opening degree closed loop.

[0021] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A variable valve seating buffer mechanism, comprising a cylinder head and valves, wherein an oil passage is provided inside the cylinder head, the oil passage is connected to an oil pan outside the cylinder head through an oil drain hole, the valve is connected to the end of the oil passage and returns to its original position via a valve spring, characterized in that: The cylinder head is also provided with a slide valve at the corresponding oil unloading hole. The slide valve has at least one oil outlet hole, which is the same diameter and direction as the oil unloading hole. The cylinder head is also fixed with an electromagnet at the top of the corresponding slide valve. The electromagnet is covered with an electromagnetic coil to be electrically connected to an external ECU. After the external ECU controls the power to be turned on, the valve core inside the slide valve can slide radially perpendicular to the oil unloading hole under the action of the electromagnetic coil, thereby realizing the opening and closing of the oil outlet hole and the oil unloading hole.

2. The variable valve seating buffer mechanism according to claim 1, characterized in that: The valve body has a valve cavity, and the valve core inside the slide valve can slide up and down within the valve cavity.

3. A control method for the variable valve seating buffer mechanism according to any one of claims 1-2, characterized in that, Includes the following steps: S1. Set the valve displacement pulse spectrum based on rotational speed and load; S2. Calibrate the valve displacement pulse spectrum based on the actual operating points and conditions of the engine test bench; S3. Subtract the opening value output by the calibrated pulse spectrum in S2 from the actual opening value finally obtained by the external actuator; S4. The difference in S3, after PID adjustment, is added to the feedforward value of the opening degree and converted into a current value through the characteristic curve of the slide valve assembly. This current value is then used to synchronously drive the slide valve to move to the set value, thus achieving a closed-loop opening degree.

4. The variable valve seating buffer mechanism according to claim 3, characterized in that: The operating conditions in step S2 include oil pressure and oil temperature.

5. A variable valve seating buffer mechanism according to claim 3, characterized in that: A current closed loop is added inside the opening closed loop to ensure accurate control current.

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