Control oil passage of variable compression ratio engine, variable compression ratio engine, and automobile

Abstract

The application discloses a control oil circuit of a variable compression ratio engine, the variable compression ratio engine and an automobile. The control oil circuit comprises a hydraulic cavity, a hydraulic drive assembly, an oil passage assembly and an oil inlet and outlet control assembly. The hydraulic drive assembly is slidably arranged in the hydraulic cavity and separates the hydraulic cavity into upper and lower hydraulic cavities. The hydraulic drive assembly is used for connecting a control shaft. The oil passage assembly is connected with the upper and lower hydraulic cavities respectively. The oil inlet and outlet control assembly is used for controlling the passing state of the oil passage assembly, so as to control the oil inlet and outlet states of the upper and lower hydraulic cavities. The passing state of the oil passage assembly is controlled by the oil inlet and outlet control assembly, the power for driving the hydraulic drive assembly to move is provided by pistons of the engine, the volume of the upper and lower hydraulic cavities is changed, when the hydraulic drive assembly cannot slide again under the action of the cavity wall of one cavity and the oil in another cavity, the state of the control shaft is stable, the engine can be reliably switched to a high compression ratio state or a low compression ratio state, the cost and space requirement are reduced, and the thermal efficiency of the engine is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of engine, in particular to the control oil circuit of variable compression ratio engine, variable compression ratio engine and automobile. BACKGROUND

[0002] Variable compression ratio technology is a revolutionary technology in engine. High compression ratio can improve engine thermal efficiency and reduce fuel consumption at low load, and low compression ratio can improve engine power and torque at high load to meet the power requirement. Currently, variable compression ratio engines with multi-link structure have been mass-produced. The main components for driving compression ratio switching in the multi-link form variable compression ratio scheme are motors, and harmonic reducers are added in the middle to ensure that the rotation speed is not too high when driving the multi-link. This scheme increases the demand for engine space and increases the cost. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a control oil circuit of variable compression ratio engine, variable compression ratio engine and automobile to solve the problems of high demand for engine space and high cost of existing schemes.

[0004] To solve the above technical problems, the embodiment of the present application provides a control oil circuit of variable compression ratio engine, which comprises a hydraulic cavity, a hydraulic drive assembly, an oil passage assembly and an oil inlet and outlet control assembly.

[0005] The hydraulic drive assembly is arranged in the hydraulic cavity and divides the hydraulic cavity into an upper hydraulic cavity and a lower hydraulic cavity; and the hydraulic drive assembly is used for connecting a control shaft.

[0006] The oil passage assembly is connected with the upper hydraulic cavity and the lower hydraulic cavity respectively.

[0007] The oil inlet and outlet control assembly is used for controlling the passing state of the oil passage assembly to control the oil inlet and outlet state of the upper hydraulic cavity and the lower hydraulic cavity.

[0008] Optionally, the oil passage assembly comprises a main oil supply passage, an upper oil inlet passage, an upper oil discharge passage, a lower oil inlet passage and a lower oil discharge passage; and the oil inlet and outlet control assembly comprises an upper oil inlet one-way valve, an upper oil discharge one-way valve, a lower oil inlet one-way valve, a lower oil discharge one-way valve and an oil passage switch.

[0009] The upper oil inlet passage is connected with the main oil supply passage and the upper hydraulic cavity, the upper oil inlet one-way valve allows oil to pass from the main oil supply passage to the upper hydraulic cavity in one direction, the upper oil discharge passage is connected with the upper hydraulic cavity, and the upper oil discharge one-way valve allows oil in the upper hydraulic cavity to be discharged outward in one direction through the upper oil discharge passage.

[0010] The lower oil inlet channel is communicated with the main oil supply channel and the lower hydraulic cavity, the lower oil inlet one-way valve allows oil to pass from the main oil supply channel to the lower hydraulic cavity in one direction, the lower oil discharge channel is communicated with the lower hydraulic cavity, and the lower oil discharge one-way valve allows oil in the lower hydraulic cavity to be discharged outward in one direction through the lower oil discharge channel;

[0011] The oil channel switch is used to open or close the upper oil discharge channel and the lower oil discharge channel.

[0012] Optionally, one end of the upper oil discharge channel is communicated with the upper hydraulic cavity, and the other end is communicated with the lower hydraulic cavity, and the upper oil discharge one-way valve allows oil in the upper hydraulic cavity to be discharged to the lower hydraulic cavity in one direction through the upper oil discharge channel;

[0013] One end of the lower oil discharge channel is communicated with the upper hydraulic cavity, and the other end is communicated with the lower hydraulic cavity, and the lower oil discharge one-way valve allows oil in the lower hydraulic cavity to be discharged to the lower hydraulic cavity in one direction through the lower oil discharge channel.

[0014] Optionally, the oil channel switch is a two-position control valve, which is used to control one of the upper oil discharge channel and the lower oil discharge channel to be opened and the other to be closed.

[0015] Optionally, the upper oil inlet one-way valve is arranged in the upper oil inlet channel, and the lower oil inlet one-way valve is arranged in the lower oil inlet channel.

[0016] The upper oil discharge one-way valve is arranged in the upper oil discharge channel, and the lower oil discharge one-way valve is arranged in the lower oil discharge channel.

[0017] Optionally, the main oil supply channel, the upper hydraulic cavity, the lower hydraulic cavity, the upper oil inlet channel, the lower oil inlet channel, the upper oil discharge channel and the lower oil discharge channel are partial of a cylinder block.

[0018] Optionally, when the hydraulic drive assembly moves upward to a limit position in the hydraulic cavity, the volume of the upper hydraulic cavity is 0; and when the hydraulic drive assembly moves downward to a limit position in the hydraulic cavity, the volume of the lower hydraulic cavity is 0.

[0019] The embodiment of the present application also provides an engine, which comprises a piston, an upper connecting rod, a rocker arm assembly, a crankshaft, a lower connecting rod, a control shaft and the aforementioned control oil circuit.

[0020] The upper end of the upper connecting rod is rotatably connected to the piston, and the lower end is rotatably connected to the rocker arm assembly.

[0021] The rocker arm assembly is rotatably connected to the crankshaft.

[0022] The upper end of the lower connecting rod is rotatably connected to the rocker arm assembly, and the lower end is rotatably connected to the control shaft.

[0023] The hydraulic drive assembly is connected to the control shaft and is used to stabilize the control shaft at different rotation angles to adjust the compression ratio of the engine.

[0024] Optionally, when the piston is subjected to downward combustion pressure, the control shaft can push the hydraulic drive assembly upward, and when the piston is subjected to upward reciprocating force, the control shaft can push the hydraulic drive assembly downward.

[0025] This invention also provides a vehicle including the aforementioned engine.

[0026] The variable compression ratio engine control circuit, variable compression ratio engine, and automobile provided in this invention embodiment have a hydraulic drive assembly that tends to slide relative to the hydraulic chamber due to the power from the piston. The oil inlet / outlet control assembly controls one of the upper and lower hydraulic chambers to be in an oil outlet state and the other to be in an oil inlet state. The hydraulic drive assembly can slide to reduce the volume of the chamber in the oil outlet state, while the other chamber is inlet. When the volume of the chamber in the oil outlet state becomes the minimum, the hydraulic drive assembly can no longer slide under the action of the chamber wall of one chamber and the oil in the other chamber. The control shaft is stable, and the engine is in a high compression ratio or low compression ratio state, thereby achieving reliable compression ratio switching. There is no need to set up an additional power source to stabilize the control shaft, reducing the cost of engine parts, reducing space requirements, reducing the energy demand during the compression ratio switching process, and improving the thermal efficiency of the engine. There is no need to configure additional energy for switching compression ratios. Attached Figure Description

[0027] Figure 1 A partial structural schematic diagram of a variable compression ratio engine provided in an embodiment of the present invention;

[0028] Figure 2 for Figure 1 The diagram shows a simplified structure of the control oil circuit for a variable compression ratio engine.

[0029] Figure 3 for Figure 1 The diagram shows the structure of a variable compression ratio engine under high compression ratio conditions.

[0030] Figure 4 for Figure 1 The diagram shows the structure of the control oil circuit of a variable compression ratio engine under high compression ratio conditions.

[0031] Figure 5 for Figure 1 The diagram shows the structure of a variable compression ratio engine in a low compression ratio state.

[0032] Figure 6 for Figure 1The control oil circuit of the variable compression ratio engine shown in the low compression ratio state structure diagram;

[0033] The figures in the specification are as follows:

[0034] 1, piston; 2, upper connecting rod; 3, rocker arm assembly; 4, crankshaft; 5, lower connecting rod; 6, control shaft; 7, transmission assembly; A, control oil circuit; 8, hydraulic drive assembly;

[0035] 901, upper hydraulic chamber; 902, lower hydraulic chamber;

[0036] 1001, upper oil inlet check valve; 1002, upper oil discharge check valve; 1003, lower oil inlet check valve; 1004, lower oil discharge check valve; 1005, oil passage switch;

[0037] 1101, main oil supply passage; 1102, upper oil inlet passage; 1103, upper oil discharge passage; 1104, lower oil inlet passage; 1105, lower oil discharge passage. DETAILED DESCRIPTION

[0038] In order to make the technical problems solved by the present application, technical solutions and beneficial effects more clear, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0039] As Figure 1 shown, the control oil circuit A of the variable compression ratio engine provided by the embodiment of the present application includes a hydraulic chamber, a hydraulic drive assembly 8, an oil passage assembly and an oil inlet and outlet control assembly;

[0040] The hydraulic drive assembly 8 is slidably arranged in the hydraulic chamber and divides the hydraulic chamber into an upper hydraulic chamber 901 and a lower hydraulic chamber 902; the hydraulic drive assembly 8 is used to connect the control shaft 6;

[0041] The oil passage assembly is respectively communicated with the upper hydraulic chamber 901 and the lower hydraulic chamber 902;

[0042] The oil inlet and outlet control assembly is used to control the passing state of the oil passage assembly, so as to control the oil inlet and outlet state of the upper hydraulic chamber 901 and the lower hydraulic chamber 902. In this application, for the convenience of expression, the upper hydraulic chamber 901 and the lower hydraulic chamber 902 are collectively referred to as the chamber, and the variable compression ratio engine is simply referred to as the engine;

[0043] Specifically, when the piston 1 of the engine is subjected to an upward reciprocating force, the hydraulic drive assembly 8 is subjected to a downward force or an upward force indirectly transmitted from the piston 1, and when the piston 1 is subjected to a downward combustion explosion pressure, the hydraulic drive assembly 8 is subjected to an upward force or a downward force indirectly transmitted from the piston 1. However, the general upward reciprocating force is less than the downward combustion explosion pressure, and preferably, when the piston 1 is subjected to the downward combustion explosion pressure, the hydraulic drive assembly 8 is subjected to the upward force from the piston 1, and when the piston 1 is subjected to the upward reciprocating force, the hydraulic drive assembly 8 is subjected to the downward force from the piston 1. The deficiency of the downward force from the piston 1 can be compensated by the gravity of the hydraulic drive assembly 8, and the responsiveness of the engine compression ratio switching can be improved.

[0044] In use, the lubricating oil of the engine enters the oil passage assembly, and when the piston 1 of the engine is subjected to an upward reciprocating force or a downward combustion explosion pressure, the force is transmitted to the hydraulic drive assembly 8 through the control shaft 6, so that the hydraulic drive assembly 8 has a tendency to slide relative to the hydraulic cavity;

[0045] When the compression ratio of the engine needs to be switched, the in-out oil state of the upper hydraulic cavity 901 and the in-out oil state of the lower hydraulic cavity 902 are controlled by the in-out oil control assembly, so that one of the upper hydraulic cavity 901 and the lower hydraulic cavity 902 is in an oil-out state, and the other is in an oil-in state; when the hydraulic drive assembly 8 is subjected to a force from the piston 1 towards the oil-out cavity, the hydraulic drive assembly 8 slides towards the cavity to reduce the volume of the cavity, and the oil in the cavity is discharged, and the oil-in cavity is filled with oil; when the hydraulic drive assembly 8 is subjected to a force from the piston 1 towards the oil-in cavity, the volume of the upper hydraulic cavity 901 and the volume of the lower hydraulic cavity 902 remain unchanged, and the lubricating oil in both cavities remains in a state of not in or out; after several cycles of the engine, the lubricating oil in one of the upper hydraulic cavity 901 and the lower hydraulic cavity 902 only enters and does not exit, the volume of the cavity changes to the maximum and is filled with lubricating oil, and the other cavity only exits and does not enter, the volume of the cavity changes to the minimum, at this time, the state of the control shaft 6 is stable, and the engine is in a high compression ratio state (such as shown in Figure 3 and Figure 4 or a low compression ratio state (such as shown in Figure 5 and Figure 6 ).

[0046] The control oil circuit of the variable compression ratio engine provided by the embodiment of the application is as follows: the hydraulic drive assembly 8 has a tendency to slide relative to the hydraulic cavity under the power from the piston 1, the in-out oil control assembly controls one of the upper hydraulic cavity 901 and the lower hydraulic cavity 902 to be in the oil out state and the other to be in the oil in state, the hydraulic drive assembly 8 can slide to reduce the volume of the cavity in the oil out state and the other cavity is in the oil in state, when the volume of the cavity in the oil out state becomes the minimum, the hydraulic drive assembly 8 cannot slide any more under the action of the oil in the cavity wall of one cavity (i.e. the cavity in the oil out state) and the other cavity (i.e. the cavity in the oil in state), the state of the control shaft 6 is stable, the engine is in the high compression ratio or low compression ratio state, the reliable compression ratio switching is realized, no additional power source (such as a driving motor or a hydraulic pump) is needed to stabilize the control shaft 6, the part cost of the engine is reduced, the space requirement is reduced, the energy requirement in the process of switching the compression ratio is reduced, the thermal efficiency of the engine is improved, and no additional energy source for switching the compression ratio is needed.

[0047] In an embodiment, as shown in Figure 1 and Figure 2 , the oil passage assembly comprises a main oil supply passage 1101, an upper oil in passage 1102, an upper oil out passage 1103, a lower oil in passage 1104 and a lower oil out passage 1105; the in-out oil control assembly comprises an upper oil in one-way valve 1001, an upper oil out one-way valve 1002, a lower oil in one-way valve 1003, a lower oil out one-way valve 1004 and an oil passage switch 1005;

[0048] The upper oil in passage 1102 connects the main oil supply passage 1101 and the upper hydraulic cavity 901, the upper oil in one-way valve 1001 allows the oil to pass from the main oil supply passage 1101 to the upper hydraulic cavity 901 in one direction, the upper oil out passage 1103 connects the upper hydraulic cavity 901, and the upper oil out one-way valve 1002 allows the oil in the upper hydraulic cavity 901 to be discharged outward in one direction through the upper oil out passage 1103;

[0049] The lower oil in passage 1104 connects the main oil supply passage 1101 and the lower hydraulic cavity 902, the lower oil in one-way valve 1003 allows the oil to pass from the main oil supply passage 1101 to the lower hydraulic cavity 902 in one direction, the lower oil out passage 1105 connects the lower hydraulic cavity 902, and the lower oil out one-way valve 1004 allows the oil in the lower hydraulic cavity 902 to be discharged outward in one direction through the lower oil out passage 1105;

[0050] The oil passage switch 1005 is used to open or close the upper oil out passage 1103 and open or close the lower oil out passage 1105.

[0051] The upper oil inlet check valve 1001, the upper oil discharge check valve 1002, the lower oil inlet check valve 1003 and the lower oil discharge check valve 1004 are common check valves, only allowing lubricating oil to pass in a certain direction, and not allowing the lubricating oil to pass in the opposite direction. The oil passage switch 1005 controls the opening and closing of the upper oil discharge passage 1103 and the lower oil discharge passage 1105. The structure is simple, the space requirement of the engine is reduced, high-performance sub-components are not required, the failure rate is low, the reliability is high, the cost is low, and the compression ratio switching of the engine can be completed by only controlling the oil passage switch 1005. The control is simple and easy to implement.

[0052] Taking the upward force of the hydraulic drive assembly 8 from the piston 1 when the piston 1 is subjected to the downward combustion pressure and the downward force of the hydraulic drive assembly 8 from the piston 1 when the piston 1 is subjected to the upward reciprocating force as examples, the compression switching process of the engine of the embodiment is as follows:

[0053] I. When the engine needs to be switched to the high compression ratio state:

[0054] The oil passage switch closes the upper oil discharge passage 1103 and opens the lower oil discharge passage 1105. During the operation of the engine, the main oil supply passage 1101 continuously supplies oil. Since the upper oil inlet check valve 1001 and the lower oil inlet check valve 1003 are check valves, the upper hydraulic chamber 901 and the lower hydraulic chamber 902 allow lubricating oil to enter.

[0055] When the piston 1 is subjected to the upward reciprocating force, the hydraulic drive assembly 8 has a downward movement tendency. Although the lower oil inlet check valve 1003 allows lubricating oil to enter the lower hydraulic chamber 902 from the main oil supply passage 1101, the pressure in the lower hydraulic chamber 902 is greater than that in the main oil supply passage 1101 at this moment, so the lubricating oil cannot actually enter the lower hydraulic chamber 902. The upper oil inlet check valve 1001 allows lubricating oil to enter the upper hydraulic chamber 901 from the main oil supply passage 1101. At the same time, since the lower oil discharge passage 1105 is open, the lubricating oil accumulated in the original lower hydraulic chamber 902 rapidly discharges through the lower oil discharge passage 1105 under the downward pressure of the hydraulic drive assembly 8. And during the downward movement of the hydraulic drive assembly 8, the volume of the upper hydraulic chamber 901 increases, and a vacuum degree is generated, which further rapidly absorbs the lubricating oil in the main oil supply passage 1101, thereby rapidly improving the switching responsiveness of the compression ratio.

[0056] When the piston 1 is subjected to the downward combustion pressure, the hydraulic drive assembly 8 has an upward movement tendency. At this moment, since the upper oil discharge passage 1103 is closed, the lubricating oil in the upper hydraulic chamber 901 is subjected to the upward pressure of the hydraulic drive assembly 8 and cannot be discharged. The pressure in the upper hydraulic chamber 901 is greater than that in the main oil supply passage 1101, the upper oil supply passage 1102 cannot supply oil, and the upper hydraulic chamber 901 keeps the lubricating oil from entering and leaving. At the same time, since the volume of the upper hydraulic chamber 901 does not decrease, the hydraulic drive assembly 8 cannot move upward, the lower hydraulic chamber 902 cannot generate a vacuum degree, and the lower hydraulic chamber 902 keeps the lubricating oil from entering and leaving.

[0057] After several cycles of the engine, the lubricating oil in the upper hydraulic chamber 901 only enters but does not exit, the volume changes to the maximum and is filled with lubricating oil, and the lower hydraulic chamber 902 only exits but does not enter, the volume changes to the minimum. At this time, the state of the control shaft 6 is stable, and the engine is in a high compression ratio state (as shown in Figure 3 and Figure 4 ). Figure 3 In the middle d1, the distance from the top of the piston 1 to the top of the combustion chamber is shown.

[0058] II. When the engine needs to switch to a low compression ratio state:

[0059] The oil passage switch opens the upper oil drain 1103 and closes the lower oil drain 1105. During engine operation, the main oil supply 1101 is always continuously supplied with oil. Since the upper oil inlet one-way valve 1001 and the lower oil inlet one-way valve 1003 are both one-way valves, the upper hydraulic chamber 901 and the lower hydraulic chamber 902 allow lubricating oil to enter them;

[0060] When the piston 1 is subjected to downward combustion pressure, the hydraulic drive assembly 8 will have a tendency to move upward. Although the upper oil inlet one-way valve 1001 allows lubricating oil to enter the upper hydraulic chamber 901 from the main oil supply 1101, at this moment the pressure in the upper hydraulic chamber 901 is greater than that in the main oil supply 1101, so the lubricating oil cannot actually enter the upper hydraulic chamber 901. The lower oil inlet one-way valve 1003 allows lubricating oil to enter the lower hydraulic chamber 902 from the main oil supply 1101, and at the same time, since the upper oil drain 1103 is open, the original lubricating oil accumulated in the upper hydraulic chamber 901 is quickly drained through the upper oil drain 1103 under the upward pressure of the hydraulic drive assembly 8. During the upward movement of the hydraulic drive assembly 8, the volume of the lower hydraulic chamber 902 increases and a vacuum degree is generated, which further rapidly absorbs lubricating oil from the main oil supply 1101, thereby rapidly improving the switching responsiveness of the compression ratio.

[0061] When the piston 1 is subjected to upward reciprocating force, the hydraulic drive assembly 8 will have a tendency to move downward. Since the lower oil drain 1105 is closed, the lubricating oil in the lower hydraulic chamber 902 is subjected to the downward pressure of the hydraulic drive assembly 8 and cannot be drained. The pressure in the lower hydraulic chamber 902 is greater than that in the main oil supply 1101, so the lower oil inlet 1104 cannot supply oil, and the lower hydraulic chamber 902 keeps the lubricating oil from entering and exiting. At the same time, since the volume of the lower hydraulic chamber 902 does not decrease, the hydraulic drive assembly 8 cannot move downward, and the upper hydraulic chamber 901 does not generate a vacuum degree, so the upper hydraulic chamber 901 keeps the lubricating oil from entering and exiting.

[0062] After several cycles of the engine, the lubricating oil in the upper hydraulic chamber 901 only enters but does not exit, the volume changes to the maximum and is filled with lubricating oil, and the lower hydraulic chamber 902 only exits but does not enter, the volume changes to the minimum. At this time, the state of the control shaft 6 is stable, and the engine is in a low compression ratio state (as shown in Figure 5 andFigure 6 as shown, Figure 5 d2 shows the distance from the top of the piston 1 to the top of the combustion chamber.

[0063] In an embodiment, as shown in Figure 2 , Figure 4 and Figure 6 , one end of the upper oil drain passage 1103 is communicated with the upper hydraulic chamber 901, and the other end is communicated with the lower hydraulic chamber 902, and the upper oil drain check valve 1002 allows the oil in the upper hydraulic chamber 901 to drain to the lower hydraulic chamber 902 through the upper oil drain passage 1103 in one direction;

[0064] One end of the lower oil drain passage 1105 is communicated with the upper hydraulic chamber 901, and the other end is communicated with the lower hydraulic chamber 902, and the lower oil drain check valve 1004 allows the oil in the lower hydraulic chamber 902 to drain to the lower hydraulic chamber 902 through the lower oil drain passage 1105 in one direction.

[0065] In an embodiment, as shown in Figure 2 , Figure 4 and Figure 6 , the oil passage switch 1005 is a two-position control valve for controlling one of the upper oil drain passage 1103 and the lower oil drain passage 1105 to be open, and the other to be closed. Without setting a control valve for the upper oil drain passage 1103 and the lower oil drain passage 1105 respectively, the structure is simplified, and when the working state of the two-position control valve is switched, the opening and closing states of the upper oil drain passage 1103 and the lower oil drain passage 1105 are opposite, which also simplifies the control, making the switching of the compression ratio of the engine more convenient.

[0066] In an embodiment, the main oil supply passage 1101, the upper hydraulic chamber 901, the lower hydraulic chamber 902, the upper oil inlet passage 1102, the lower oil inlet passage 1104, the upper oil drain passage 1103 and the lower oil drain passage 1105 are part of the cylinder block, i.e. the main oil supply passage 1101, the upper hydraulic chamber 901, the lower hydraulic chamber 902, the upper oil inlet passage 1102, the lower oil inlet passage 1104, the upper oil drain passage 1103 and the lower oil drain passage 1105 are directly formed on the cylinder block, without the need for additional independent structures for passing and accommodating lubricating oil, simplifying the structure and eliminating the need for assembly.

[0067] Specifically, the main oil supply passage 1101, the upper oil inlet passage 1102, the lower oil inlet passage 1104, the upper oil drain passage 1103 and the lower oil drain passage 1105 are all oil passages formed by machining the cylinder block, and are preferably cylindrical oil passages, which are simple in structure and have small flow resistance of lubricating oil. The main oil supply passage 1101 serves as the main oil passage of the engine, and its branches supply lubricating oil to various parts, components and systems of the engine that require lubricating oil.

[0068] Specifically, as shown in Figure 1As shown, the hydraulic chamber is a receiving cavity formed by machining the cylinder body. Preferably, the hydraulic chamber is an arc-shaped cavity because the control shaft 6 rotates under the drive of the piston 1. When the hydraulic chamber is an arc-shaped cavity, the hydraulic drive assembly 8 can also rotate around a pivot to slide within the hydraulic chamber, which simplifies the connection structure between the control shaft 6 and the hydraulic drive assembly 8.

[0069] In one embodiment, when the hydraulic drive assembly 8 moves upward to its limit position within the hydraulic chamber, the volume of the upper hydraulic chamber 901 is zero; when the hydraulic drive assembly 8 moves downward to its limit position within the hydraulic chamber, the volume of the lower hydraulic chamber 902 is zero. This more effectively utilizes the space within the hydraulic chamber, allowing the lubricating oil in a smaller hydraulic chamber to provide sufficient oil pressure to stabilize the position of the hydraulic drive assembly 8, thus increasing structural compactness.

[0070] like Figure 1 As shown, this embodiment of the invention also provides a variable compression ratio engine, including a piston 1, an upper connecting rod 2, a rocker arm assembly 3, a crankshaft 4, a lower connecting rod 5, a control shaft 6, and a control oil circuit A;

[0071] The upper end of the upper connecting rod 2 is rotatably connected to the piston 1, and the lower end is rotatably connected to the rocker arm assembly 3;

[0072] The rocker arm assembly 3 is rotatably connected to the crankshaft 4;

[0073] The upper end of the lower connecting rod 5 is rotatably connected to the rocker arm assembly 3, and the lower end is rotatably connected to the control shaft 6;

[0074] The hydraulic drive assembly 8 is connected to the control shaft 6 and is used to stabilize the control shaft 6 at different rotation angles to adjust the engine's compression ratio. The piston 1, upper connecting rod 2, rocker arm assembly 3, crankshaft 4, lower connecting rod 5, and control shaft 6 are existing engine components; however, in the existing design, these components do not transmit the driving force used to adjust the compression ratio.

[0075] The control shaft 6 drives the hydraulic drive assembly 8 to change the volume of the upper hydraulic chamber 901 and the lower hydraulic chamber 902. The position of the hydraulic drive assembly 8 is stabilized by the oil pressure of the hydraulic chamber wall on one side and the lubricating oil on the other side. The hydraulic drive assembly 8 then prevents the control shaft 6 from rotating, thus completing the engine's compression ratio switching. This eliminates the need for an additional power source (such as a drive motor or hydraulic pump) to stabilize the control shaft 6, reducing engine component costs, space requirements, and the additional energy demand during compression ratio switching, thereby improving engine thermal efficiency.

[0076] Preferably, the oil passage switch is in communication connection with the engine ECU, and the engine ECU automatically judges whether the compression ratio state needs to be switched according to the related information such as the rotating speed and the load, and controls the working state of the oil passage switch if the compression ratio state needs to be switched. Specifically, the engine is switched to the high compression ratio state at the medium and low load, and is switched to the low compression ratio state at the high load.

[0077] In an embodiment, as shown in Figure 1 The connecting structure between the control shaft 6 and the hydraulic drive assembly 8 is reasonably arranged, so that the control shaft 6 can push the hydraulic drive assembly 8 upward when the piston 1 is subjected to the downward combustion explosion pressure, and the control shaft 6 can push the hydraulic drive assembly 8 downward when the piston 1 is subjected to the upward reciprocating force. When the piston 1 is subjected to the downward combustion explosion pressure, the hydraulic drive assembly 8 is subjected to the upward force from the piston 1, and the combustion explosion pressure is large, so that the hydraulic drive assembly 8 can be quickly moved upward when the upper hydraulic cavity 901 is in the oil outlet state, and when the piston 1 is subjected to the upward reciprocating force, the hydraulic drive assembly 8 is subjected to the downward force from the piston 1, and the gravity of the hydraulic drive assembly 8 can compensate for the insufficient downward force from the piston 1, so that the hydraulic drive assembly 8 can be quickly moved downward when the lower hydraulic cavity 902 is in the oil outlet state, thereby improving the responsiveness of the engine compression ratio switching.

[0078] Specifically, as shown in Figure 1 The transmission assembly 7 can be used to connect the control shaft 6 and the hydraulic drive assembly 8, the transmission assembly 7 includes a driving gear fixed on the control shaft 6 and a driven gear fixed on the hydraulic drive assembly 8, and the driving gear is engaged with the driven gear.

[0079] The embodiment of the present application also provides a car comprising the variable compression ratio engine according to any one of the foregoing embodiments. The control oil passage of the variable compression ratio engine is beneficial to reduce the volume of the power assembly and is low in cost.

[0080] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A control oil passage of a variable compression ratio engine characterized by, The hydraulic cavity, the hydraulic drive assembly, the oil passage assembly and the oil inlet and outlet control assembly are included. The hydraulic drive assembly is slidably arranged in the hydraulic cavity and separates the hydraulic cavity into an upper hydraulic cavity and a lower hydraulic cavity. The oil passage assembly is respectively communicated with the upper hydraulic cavity and the lower hydraulic cavity. The oil inlet and outlet control assembly is used to control the passing state of the oil passage assembly to control the oil inlet and outlet state of the upper hydraulic cavity and the lower hydraulic cavity. The oil passage assembly includes a main oil supply passage, an upper oil inlet passage, an upper oil discharge passage, a lower oil inlet passage and a lower oil discharge passage. The upper oil inlet passage is communicated with the main oil supply passage and the upper hydraulic cavity. The upper oil inlet one-way valve allows the oil to pass from the main oil supply passage to the upper hydraulic cavity in one direction. The lower oil inlet passage is communicated with the main oil supply passage and the lower hydraulic cavity.

2. The control oil passage of the variable compression ratio engine according to claim 1, characterized by, The lower oil inlet one-way valve allows the oil to pass from the main oil supply passage to the lower hydraulic cavity in one direction. The oil passage switch is used to open or close the upper oil discharge passage and the lower oil discharge passage.

3. The control oil passage of the variable compression ratio engine according to claim 1, characterized by, One end of the upper oil discharge passage is communicated with the upper hydraulic cavity and the other end is communicated with the lower hydraulic cavity.

4. The control oil passage of the variable compression ratio engine according to claim 1, characterized by, One end of the lower oil discharge passage is communicated with the upper hydraulic cavity and the other end is communicated with the lower hydraulic cavity. The oil passage switch is a two-position control valve and is used to control one of the upper oil discharge passage and the lower oil discharge passage to be opened and the other to be closed.

5. The control oil passage of the variable compression ratio engine according to claim 1, characterized by, The upper oil inlet one-way valve is arranged in the upper oil inlet passage and the lower oil inlet one-way valve is arranged in the lower oil inlet passage.

6. The control oil passage of the variable compression ratio engine according to claim 1, characterized by, The upper oil discharge one-way valve is arranged in the upper oil discharge passage and the lower oil discharge one-way valve is arranged in the lower oil discharge passage.

7. A variable compression ratio engine characterized by, The main oil supply passage, the upper hydraulic cavity, the lower hydraulic cavity, the upper oil inlet passage, the lower oil inlet passage, the upper oil discharge passage and the lower oil discharge passage are partial parts of a cylinder block. When the hydraulic drive assembly moves up to the limit position in the hydraulic cavity, the volume of the upper hydraulic cavity is 0. The piston, the upper connecting rod, the rocker arm assembly, the crankshaft, the lower connecting rod, the control shaft and the control oil passage of any one of claims 1-6 are included. The upper end of the upper connecting rod is rotatably connected to the piston and the lower end is rotatably connected to the rocker arm assembly. The rocker arm assembly is rotatably connected to the crankshaft. The upper end of the lower connecting rod is rotatably connected to the rocker arm assembly and the lower end is rotatably connected to the control shaft. The hydraulic drive assembly is drivingly connected to the control shaft and is used to stabilize the control shaft at different rotational angles to adjust the compression ratio of the engine.

8. A variable compression ratio engine according to claim 7, characterized by The control shaft can push the hydraulic drive assembly upward when the piston is subjected to downward combustion pressure, and the control shaft can push the hydraulic drive assembly downward when the piston is subjected to upward reciprocating force.

9. An automobile characterized by comprising: A variable compression ratio engine comprising the control shaft of claim 7 or 8.

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