Internal combustion engine crankshaft with variable compression ratio

Abstract

The invention discloses an internal combustion engine crankshaft with a variable compression ratio, which is a split crankshaft, including a crankpin and a crankshaft crank, one end of the crankpin is connected to the crankshaft crank on one side through a driving mechanism, and the other end of the crankpin is connected to the crankshaft crank on the other side through a locking mechanism, and the main part of the crankpin and the piston connecting rod is an eccentric shaft structure; the crankpin is driven to rotate by the driving mechanism, and the crankpin rotation angle is locked by the locking mechanism to change the upper and lower dead point positions of the piston connecting rod. The crankpin is optimized to an eccentric structure, and a hydraulic system, a driving mechanism and a locking mechanism are used to drive the crankpin to rotate and lock, so as to change the upper dead point position of the piston and complete the compression ratio change.

Description

Technical Field

[0001] The invention relates to an internal combustion engine crankshaft with a variable compression ratio, and is particularly suitable for medium and large engines such as marine engines. Background Art

[0002] Under the increasingly stringent emission regulations and fuel economy requirements, the variable compression ratio structure is still a hot technology and has a high demand in the engine field, especially in the field of large and medium-sized diesel engines. The compression ratio of the engine is an important parameter that affects the engine performance. In conventional engines, the compression ratio of gasoline engines is generally between 8-12, and the compression ratio of diesel engines can reach 12-22. A fixed compression ratio cannot give full play to the performance of the engine. When running at low load and low speed, the thermal efficiency of the engine is very low, and a larger compression ratio can be used; if the compression ratio is fixed, it is easy to cause deflagration when running at high load and high speed. At this time, the variable compression ratio can handle this problem well.

[0003] The methods currently used in variable compression ratio engines are mainly divided into the following categories: 1. Using a mobile cylinder head, the compression ratio is changed by floating the cylinder head position up and down, but due to the complex structure, poor reliability and high cost, it cannot be mass-produced; 2. "VCR" variable compression ratio technology uses the lever principle. When the eccentric shaft rotates, the control rod will move up and down. Because of the action of the lever, the connecting rod will move in the opposite direction of the eccentric shaft, which will change the position of the compression top dead center piston, thereby changing the compression ratio; 3. "VCRi" variable compression ratio technology has an additional set of hydraulic control compared to traditional engines, which changes the top dead center position of the piston and thus changes the compression ratio; 4. "VC-T" variable compression ratio technology adds a set of connecting rods under the crankshaft. Through the changes in this set of mechanisms, the piston stroke can be changed, thereby changing the compression ratio. However, the variable compression ratio engines currently used have relatively complex processes, the technology is not mature enough, and the structure is unstable. In fact, it is difficult to accurately implement or mass-produce. Since the structural space of medium and large engines such as marine engines is relatively large, it is easy to install and implement a variable compression ratio structural system, so it is of great significance to provide a variable compression ratio with simple structure and convenient operation to achieve high economy and low emissions. Summary of the invention

[0004] In order to solve the above-mentioned problems existing in the prior art, the present invention provides an internal combustion engine crankshaft with a variable compression ratio, optimizes the crankpin into an eccentric structure, and utilizes a hydraulic system, a driving mechanism and a locking mechanism to drive the crankpin to rotate and lock, thereby realizing the change of the top dead center position of the piston and completing the change of the compression ratio.

[0005] The purpose of the present invention is achieved through the following technical solutions, in conjunction with the accompanying drawings:

[0006] A crankshaft for an internal combustion engine with a variable compression ratio is a split crankshaft, comprising a crankpin 3 and a crankshaft crank 1, wherein one end of the crankpin 3 is connected to the crankshaft crank 1 on one side through a driving mechanism, and the other end of the crankpin 3 is connected to the crankshaft crank 1 on the other side through a locking mechanism, and the main part of the crankpin 3 that cooperates with the piston connecting rod 2 is an eccentric shaft structure; the crankpin 3 is driven to rotate by the driving mechanism, and the rotation angle of the crankpin 3 is locked by the locking mechanism to change the upper and lower dead point positions of the piston connecting rod 2.

[0007] Furthermore, the driving mechanism has the same structure as the locking mechanism, including a manual driving part 29 and a driving part connecting structure, wherein the driving part connecting structure is as follows: the crank pin 3 is interference fit with the crankshaft crank 1, and a square hole is provided at the outer end of the crank pin, and the cross-sectional state of the square hole matches the shape of the manual driving part 29; a positioning groove 27 is provided on the crank pin 3 and the crankshaft crank 1, and the positioning groove 27 passes through the crank pin 3 and the crankshaft crank 1, and a pin shaft 26, a positioning steel ball 28 and a return spring 16 are provided in the positioning groove 27, and the pin shaft 26 is bonded to the outer side of the positioning steel ball 28, and the inner side of the positioning steel ball abuts the return spring 16, and the inner side of the return spring 16 abuts the bottom of the positioning groove 27, and when the return spring is in the return state, the positioning steel ball 28 is located between the crank pin 3 and the crankshaft crank 1 to limit the relative rotation of the crank pin 3 and the crankshaft crank 1.

[0008] Furthermore, it also includes a hydraulic oil pump, which supplies oil to the driving mechanism and the locking structure through an oil supply circuit.

[0009] Furthermore, the structure of the driving mechanism is as follows: a stop plate 6 integrally formed with the crank pin 3 is provided at the end of the crank pin 3, a hydraulic oil chamber 8 is provided between the crank pin 3 and the crankshaft crank 1, an upper stop plate 9-1 and a lower stop plate 9-2 are respectively provided on both sides of the hydraulic oil chamber 8, and the upper stop plate 9-1 and the lower stop plate 9-2 are arranged at an angle of 180°, and the upper stop plate 9-1 and the lower stop plate 9-2 are used to stop the position of the stop plate 6; a hydraulic oil clockwise rotating inlet and a hydraulic oil quasi-clockwise rotating inlet are respectively provided at the bottom of the hydraulic oil chamber 8, and the hydraulic oil pump is connected to the hydraulic oil clockwise rotating inlet and the hydraulic oil quasi-clockwise rotating inlet through the oil supply circuit.

[0010] Furthermore, the structure of the driving mechanism is as follows: a hydraulic oil chamber 8 is provided between the end of the crank pin 3 and the crankshaft crank 1, and the cross-sectional shape of the hydraulic oil chamber 8 is elliptical; a plurality of radial grooves 11 are provided at the end of the crank pin 3, two of which are distributed at 180°, a slide 10 is provided in the radial groove 11, and a spring is provided between the slide 10 and the slide 11, the slide 10 can extend along the slide 11 and abut against the inner wall of the crankshaft crank 1, and a hydraulic oil clockwise rotating inlet and a hydraulic oil quasi-clockwise rotating inlet are respectively provided at the bottom of the hydraulic oil chamber 8, and the hydraulic oil pump is connected to the hydraulic oil clockwise rotating inlet and the hydraulic oil quasi-clockwise rotating inlet through the oil supply oil circuit.

[0011] Furthermore, the structure of the locking mechanism is as follows: the end of the crank pin 3 is clearance-fitted with the crankshaft crank 1, two radial locking grooves 15 are symmetrically provided on the crank pin 3, a plunger oil chamber 13 is provided between the bottom of the crank pin 3 and the crankshaft crank 1, the top of the plunger 14 extends into the locking groove 15, a return spring 16 is provided between the bottom of the plunger 14 and the inner wall of the crankshaft crank 1, and the hydraulic oil pump is connected to the upper chamber of the plunger oil chamber 13 through the oil supply line.

[0012] Furthermore, the structure of the locking mechanism is as follows: the end of the crank pin 3 is clearance-fitted with the crankshaft crank 1, and two radial locking grooves 15 are symmetrically provided on the crank pin 3, and a locking ball 19 is provided in the locking groove 15, and a return spring 16 is abutted between the locking ball 19 and the locking groove 15. When the return spring 16 is in the return state, the locking ball 19 is clamped between the crank pin 3 and the crankshaft crank 1, and a plunger oil chamber is provided in the crankshaft crank 1, and the top of the plunger 14 abuts against the locking ball 19, and the hydraulic oil pump is connected to the plunger oil chamber 13 through the oil supply circuit.

[0013] Furthermore, the hydraulic oil pump is connected to the oil supply circuit through an oil supply pipe interface, and the oil supply pipe interface includes an oil supply pipe sleeve 23 that is interference fit with the crankshaft crank 1, and the oil supply pipe sleeve 23 is sealed with the oil supply pipe joint 20 through a sealing gasket; a through groove is provided on the oil supply pipe sleeve 23 and the crankshaft crank 1, and a retreat groove 24 that cooperates with the through groove of the oil supply pipe sleeve 23 is provided on the oil supply pipe joint 20, and a return ball 19 is clamped between the retreat groove 24 and the oil supply pipe through groove, and a clamping spring 22 abuts between the return ball and the oil supply pipe through groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the split crankshaft structure;

[0015] Figure 2 It is a schematic diagram of the assembly structure of the crankshaft and piston connecting rod of the internal combustion engine with a variable compression ratio of the present invention;

[0016] Figure 3 This is a schematic diagram of the cross-sectional structure of the crank pin of the present invention;

[0017] Figure 4 This is a schematic diagram of the structure of the driving mechanism described in Example 1 of the present invention;

[0018] Figure 5 This is a schematic diagram of the structure of the driving mechanism described in Example 2 of the present invention;

[0019] Figure 6 This is a schematic diagram of the locking mechanism structure described in Example 3 of the present invention;

[0020] Figure 7 This is a schematic diagram of the locking mechanism structure described in Example 4 of the present invention;

[0021] Figure 8 This is a schematic diagram of the assembly structure of the oil supply pipe interface described in Examples 1 to 4 of the present invention;

[0022] Fig. 9 This is a schematic diagram of the structure of the driving mechanism described in Example 5 of the present invention;

[0023] Fig.10 This is a schematic diagram of the locking mechanism structure described in Example 5 of the present invention;

[0024] In the figure:

[0025] 1-crankshaft crank; 2-piston connecting rod; 3-crankpin; 4-crankshaft journal; 5-bearing; 6-stop plate; 8-hydraulic oil chamber; 9-1-upper stop plate; 9-2-lower stop plate; 10-slide; 11-slideway; 12-hydraulic oil; 13-plunger oil chamber; 14-hydraulic plunger; 15-locking groove; 16-return spring; 19-locking ball; 20-oil supply pipe interface; 22-clamping spring; 23-oil supply pipe sleeve; 24-retraction groove; 25-sealing gasket groove; 26-stomp pitch shaft; 27-positioning groove; 28-positioning steel ball; 29-drive shaft. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0027] A crankshaft for an internal combustion engine with a variable compression ratio is a split crankshaft, comprising a crankpin 3 and a crankshaft crank 1, wherein one end of the crankpin 3 is connected to the crankshaft crank 1 on one side through a driving mechanism, and the other end of the crankpin 3 is connected to the crankshaft crank 1 on the other side through a locking mechanism, and the main part of the crankpin 3 that cooperates with the piston connecting rod 2 is an eccentric shaft structure; the crankpin 3 is driven to rotate by the driving mechanism, and the rotation angle of the crankpin 3 is locked by the locking mechanism to change the upper and lower dead point positions of the piston connecting rod 2.

[0028] Furthermore, the driving mechanism has the same structure as the locking mechanism, including a manual driving part 29 and a driving part connecting structure, wherein the driving part connecting structure is as follows: the crank pin 3 is interference fit with the crankshaft crank 1, and a square hole is provided at the outer end of the crank pin, and the cross-sectional state of the square hole matches the shape of the manual driving part 29; a positioning groove 27 is provided on the crank pin 3 and the crankshaft crank 1, and the positioning groove 27 passes through the crank pin 3 and the crankshaft crank 1, and a pin shaft 26, a positioning steel ball 28 and a return spring 16 are provided in the positioning groove 27, and the pin shaft 26 is bonded to the outer side of the positioning steel ball 28, and the inner side of the positioning steel ball abuts the return spring 16, and the inner side of the return spring 16 abuts the bottom of the positioning groove 27, and when the return spring is in the return state, the positioning steel ball 28 is located between the crank pin 3 and the crankshaft crank 1 to limit the relative rotation of the crank pin 3 and the crankshaft crank 1.

[0029] Furthermore, it also includes a hydraulic oil pump, which supplies oil to the driving mechanism and the locking structure through an oil supply circuit.

[0030] Furthermore, the structure of the driving mechanism is as follows: a stop plate 6 integrally formed with the crank pin 3 is provided at the end of the crank pin 3, a hydraulic oil chamber 8 is provided between the crank pin 3 and the crankshaft crank 1, an upper stop plate 9-1 and a lower stop plate 9-2 are respectively provided on both sides of the hydraulic oil chamber 8, and the upper stop plate 9-1 and the lower stop plate 9-2 are arranged at an angle of 180°, and the upper stop plate 9-1 and the lower stop plate 9-2 are used to stop the position of the stop plate 6; a hydraulic oil clockwise rotating inlet and a hydraulic oil quasi-clockwise rotating inlet are respectively provided at the bottom of the hydraulic oil chamber 8, and the hydraulic oil pump is connected to the hydraulic oil clockwise rotating inlet and the hydraulic oil quasi-clockwise rotating inlet through the oil supply circuit.

[0031] Furthermore, the structure of the driving mechanism is as follows: a hydraulic oil chamber 8 is provided between the end of the crank pin 3 and the crankshaft crank 1, and the cross-sectional shape of the hydraulic oil chamber 8 is elliptical; a plurality of radial grooves 11 are provided at the end of the crank pin 3, two of which are distributed at 180°, a slide 10 is provided in the radial groove 11, and a spring is provided between the slide 10 and the slide 11, the slide 10 can extend along the slide 11 and abut against the inner wall of the crankshaft crank 1, and a hydraulic oil clockwise rotating inlet and a hydraulic oil quasi-clockwise rotating inlet are respectively provided at the bottom of the hydraulic oil chamber 8, and the hydraulic oil pump is connected to the hydraulic oil clockwise rotating inlet and the hydraulic oil quasi-clockwise rotating inlet through the oil supply oil circuit.

[0032] Furthermore, the structure of the locking mechanism is as follows: the end of the crank pin 3 is clearance-fitted with the crankshaft crank 1, two radial locking grooves 15 are symmetrically provided on the crank pin 3, a plunger oil chamber 13 is provided between the bottom of the crank pin 3 and the crankshaft crank 1, the top of the plunger 14 extends into the locking groove 15, a return spring 16 is provided between the bottom of the plunger 14 and the inner wall of the crankshaft crank 1, and the hydraulic oil pump is connected to the upper chamber of the plunger oil chamber 13 through the oil supply line.

[0033] Furthermore, the structure of the locking mechanism is as follows: the end of the crank pin 3 is clearance-fitted with the crankshaft crank 1, and two radial locking grooves 15 are symmetrically provided on the crank pin 3, and a locking ball 19 is provided in the locking groove 15, and a return spring 16 is abutted between the locking ball 19 and the locking groove 15. When the return spring 16 is in the return state, the locking ball 19 is clamped between the crank pin 3 and the crankshaft crank 1, and a plunger oil chamber is provided in the crankshaft crank 1, and the top of the plunger 14 abuts against the locking ball 19, and the hydraulic oil pump is connected to the plunger oil chamber 13 through the oil supply circuit.

[0034] Furthermore, the hydraulic oil pump supplies oil to the driving mechanism and the locking structure through the oil supply line. Figure 8 As shown, the hydraulic oil pump is connected to the oil supply circuit through an oil supply pipe interface, and the oil supply pipe interface includes an oil supply pipe sleeve 23 which is interference fit with the crankshaft crank 1, and the oil supply pipe sleeve 23 is sealed and connected to the oil supply pipe joint 20 through a sealing gasket; a through groove is provided on the oil supply pipe sleeve 23 and the crankshaft crank 1, and a retreat groove 24 which cooperates with the through groove of the oil supply pipe sleeve 23 is provided on the oil supply pipe joint 20, and a return ball 19 is clamped between the retreat groove 24 and the oil supply pipe through groove, and a clamping spring 22 abuts between the return ball and the oil supply pipe through groove.

[0035] The working principle of the present invention is briefly described below:

[0036] like Figure 2 As shown, the crankshaft of the internal combustion engine of the present invention is a split crankshaft, and the crank pin can rotate relative to the crank. Under the action of the hydraulic system, the crank pin is driven to rotate by the driving mechanism to change the position of the crank pin. When the crank pin rotates 180° and reaches the predetermined position, the locking mechanism locks the crank pin position. Figure 3 As shown, since the crankpin adopts an eccentric structure, the rotation of the crankpin will cause the upper and lower dead point positions of the piston connecting rod to change, changing the piston movement stroke position, and the maximum stroke volume and the minimum stroke volume to change. From the formula Compression ratio = maximum stroke volume / minimum stroke volume, it can be seen that the engine compression ratio has changed.

[0037] The present invention achieves the change of the upper and lower dead point positions of the crank pin shaft through the following three driving schemes and three locking mechanism schemes. Driving scheme: 1. Pendulum type hydraulic driving scheme; 2. Vane pump type hydraulic driving scheme; 3. Manual driving scheme. Locking scheme: 1. Plunger type locking scheme; 2. Locking ball locking scheme; 3. Manual locking scheme. The following are introduced in the form of embodiments:

[0038] Embodiment 1 The driving mechanism is a swing type hydraulic driving mechanism

[0039] like Figure 4As shown, the swing type hydraulic drive mechanism is: a stop plate 6 integrally formed with the crank pin 3 is provided at the end of the crank pin 3, a hydraulic oil chamber 8 is provided between the crank pin 3 and the crankshaft crank 1, an upper stop plate 9-1 and a lower stop plate 9-2 are respectively provided on both sides of the hydraulic oil chamber 8, and the upper stop plate 9-1 and the lower stop plate 9-2 are arranged at an angle of 180°, and the upper stop plate 9-1 and the lower stop plate 9-2 are used to stop the position of the stop plate 6; a hydraulic oil clockwise rotating inlet and a hydraulic oil quasi-clockwise rotating inlet are respectively provided at the bottom of the hydraulic oil chamber 8, and the hydraulic oil pump is connected to the hydraulic oil clockwise rotating inlet and the hydraulic oil quasi-clockwise rotating inlet through the oil supply oil circuit.

[0040] A hydraulic oil clockwise rotation inlet and a hydraulic oil quasi-clockwise rotation inlet are respectively provided at the bottom of the hydraulic oil chamber 8. The hydraulic oil enters the lower chamber of the hydraulic oil chamber 8 from the hydraulic oil clockwise rotation inlet through the oil supply line. The hydraulic oil fills the hydraulic oil clockwise rotation inlet. Due to the pressure difference between the upper and lower chambers of the hydraulic oil chamber 8, the stopper plate 6 is pushed by the pressure oil to drive the clockwise rotation, thereby driving the crankpin 3 to rotate. After the crankpin 3 rotates 180° clockwise, it encounters the lower stopper plate 9-2, and the rotation stops. Since the matching part of the crankpin 3 and the piston connecting rod 2 is designed as an eccentric structure, after the crankpin 3 rotates 180°, the upper and lower dead point positions of the piston connecting rod 2 are changed, thereby realizing a change in the compression ratio.

[0041] When the stop plate 6 is in the position of the lower stop plate 9-2, in order to restore it to the original compression ratio state, the hydraulic oil is introduced into the lower chamber of the hydraulic oil chamber 8 from the counterclockwise rotation inlet of the hydraulic oil through the oil supply line. Similarly, when the hydraulic oil fills the counterclockwise rotation inlet, the hydraulic oil chamber 8 has a pressure difference between the upper and lower chambers. Under the action of the pressure oil, the stop plate 6 is pushed to drive the crankpin shaft 3 to rotate counterclockwise. After rotating 180° counterclockwise, it encounters the upper stop plate 9-1 and cannot continue to rotate forward. The upper and lower dead points of the piston connecting rod 2 return to their original positions, and the compression ratio returns to its original state.

[0042] Embodiment 2 The driving mechanism is a sliding vane hydraulic driving mechanism

[0043] like Figure 5 As shown, the vane type hydraulic drive mechanism is as follows: a hydraulic oil chamber 8 is provided between the end of the crank pin 3 and the crankshaft crank 1, and the cross-sectional shape of the hydraulic oil chamber 8 is elliptical; a plurality of radial grooves 11 are provided at the end of the crank pin 3, wherein two grooves 11 are distributed at 180°, a vane 10 is provided in the radial groove 11, and a spring is provided between the vane 10 and the groove 11, the vane 10 can extend along the groove 11 and abut against the inner wall of the crankshaft crank 1, a hydraulic oil clockwise rotating inlet and a hydraulic oil quasi-clockwise rotating inlet are respectively provided at the bottom of the hydraulic oil chamber 8, and the hydraulic oil pump is respectively connected to the hydraulic oil clockwise rotating inlet and the hydraulic oil quasi-clockwise rotating inlet through the oil supply oil circuit.

[0044] A hydraulic oil clockwise rotating inlet and a hydraulic oil quasi-clockwise rotating inlet are respectively provided at the bottom of the hydraulic oil chamber 8. The hydraulic oil enters the lower left chamber of the hydraulic oil chamber 8 from the hydraulic oil clockwise rotating inlet through the oil supply line. The hydraulic oil fills the hydraulic oil clockwise inlet. Since the cross-section of the hydraulic oil chamber 8 is an elliptical shape, the transverse slide 10 and the longitudinal slide extend partly out of the slide groove 11 under the action of the spring to resist the crank. The elongation length of the transverse slide 10 is different from that of the longitudinal slide. It can be seen from the formula F=pA that there is a pressure difference between the two slides. Under the action of the torque, the slide rotates, thereby driving the crank pin 3 to rotate. After rotating 180° clockwise, the upper and lower dead point positions of the piston connecting rod of part 2 change, and the compression ratio changes.

[0045] When the slide 10 rotates 180° and is to be restored to its initial position, the hydraulic oil enters the lower right chamber of the hydraulic oil chamber 8 from the counterclockwise rotation inlet of the hydraulic oil through the oil supply line, and the hydraulic oil fills the counterclockwise rotation inlet of the hydraulic oil. Similarly, due to the different elongation lengths and pressure areas of the transverse slide 10 and the longitudinal slide, there is a pressure difference between the two slides. Under the action of the torque, the slide rotates, thereby driving the crankpin 3 to rotate, rotating 180° counterclockwise, and the upper and lower dead points of the piston connecting rod of part 2 return to their initial positions, and the compression ratio returns to its initial state.

[0046] Embodiment 3 The locking mechanism is a plunger-type hydraulic locking mechanism

[0047] like Figure 6 As shown, the plunger type hydraulic locking mechanism is as follows: the end of the crank pin 3 is clearance-matched with the crankshaft crank 1, two radial locking grooves 15 are symmetrically provided on the crank pin 3, a plunger oil chamber 13 is provided between the bottom of the crank pin 3 and the crankshaft crank 1, the top of the plunger 14 extends into the locking groove 15, a return spring 16 is provided between the bottom of the plunger 14 and the inner wall of the crankshaft crank 1, and the hydraulic oil pump is connected to the upper chamber of the plunger oil chamber 13 through an oil supply line.

[0048] The hydraulic oil enters the plunger oil chamber 13 through the oil supply line. There is a pressure difference between the plunger oil chamber 13 and the plunger lower chamber. Under the action of the hydraulic oil, the return spring 16 at the lower part of the plunger is squeezed, and the return spring 16 is displaced. The plunger 14 escapes from the locking groove 15 of the crankpin 3, so that the crankpin 3 is unlocked. At this time, the crankpin 3 starts to rotate under the drive of the driving mechanism. When the crankpin rotates 180°, the hydraulic oil pressure of the driving mechanism and the locking mechanism is removed at the same time. The plunger 14 is pushed upward into the crankpin locking groove 15 under the reaction force of the return spring 16, and the crankpin 3 is locked and cannot continue to rotate. The upper and lower dead point positions of the piston connecting rod 2 are changed, and the compression ratio is changed.

[0049] Embodiment 4 The locking mechanism is a locking ball type hydraulic locking mechanism

[0050] like Figure 7As shown, the locking ball type hydraulic locking mechanism is: the end of the crank pin 3 is clearance-matched with the crankshaft crank 1, and two radial locking grooves 15 are symmetrically provided on the crank pin 3, and a locking ball 19 is provided in the locking groove 15, and a return spring 16 is abutted between the locking ball 19 and the locking groove 15. When the return spring 16 is in the return state, the locking ball 19 is clamped between the crank pin 3 and the crankshaft crank 1, and a plunger oil chamber is provided in the crankshaft crank 1, and the top of the plunger 14 abuts against the locking ball 19, and the hydraulic oil pump is connected to the plunger oil chamber 13 through the oil supply oil circuit.

[0051] The hydraulic oil enters the plunger oil chamber through the oil supply line. The plunger 14 moves upward under the action of the hydraulic oil, presses against the locking ball 19 and squeezes the return spring 16, so that the ball is completely pushed into the locking groove 15. The return spring 16 is in a compressed state. At this time, the crank pin can rotate freely and rotates 180° under the torque provided by the drive mechanism. After rotating 180°, the upper and lower dead point positions of the piston connecting rod 2 change, and the compression ratio changes. At this time, the hydraulic oil pressure of the drive mechanism and the locking mechanism is simultaneously unloaded. Under the reaction force of the return spring 16, the locking ball 18 partially extends out of the locking groove 15, and the relative position of the crank pin and the crankshaft crank 1 is stuck by the locking ball 18, the crank pin position is locked, and the locking movement is completed.

[0052] Hydraulic system oil supply circuit of embodiment 1 to embodiment 4

[0053] The hydraulic oil pump supplies oil to the drive mechanism and the locking structure through the oil supply line. Figure 8 As shown, the hydraulic oil pump is connected to the oil supply circuit through an oil supply pipe interface, and the oil supply pipe interface includes an oil supply pipe sleeve 23 which is interference fit with the crankshaft crank 1, and the oil supply pipe sleeve 23 is sealed and connected to the oil supply pipe joint 20 through a sealing gasket; a through groove is provided on the oil supply pipe sleeve 23 and the crankshaft crank 1, and a retreat groove 24 which cooperates with the through groove of the oil supply pipe sleeve 23 is provided on the oil supply pipe joint 20, and a return ball 19 is clamped between the retreat groove 24 and the oil supply pipe through groove, and a clamping spring 22 abuts between the return ball and the oil supply pipe through groove.

[0054] The oil supply pipe joint 20 is inserted into the oil supply pipe sleeve 23. Under the action of the clamping spring 22, the return ball 19 is stuck in the retreat groove 24. Then the oil supply pump starts to supply oil to the drive mechanism and the locking mechanism through the oil supply oil circuit; after the oil pipe is rotated 90°, the locking ball of part 19 enters the retreat groove of part 24, the oil pipe is unlocked, and the oil pipe can be pulled out.

[0055] Embodiment 5 The driving mechanism level locking structure is a manual driving mechanism and a manual locking mechanism

[0056] like Fig. 9 , Fig.10As shown, the manual driving mechanism has the same structure as the manual locking mechanism, including a manual driving part 29 and a driving part connecting structure, the driving part connecting structure is: the crank pin 3 and the crankshaft crank 1 are clearance-matched, and a square hole is provided at the outer end of the crank pin, and the cross-sectional state of the square hole matches the shape of the manual driving part 29; a positioning groove 27 is provided on the crank pin 3 and the crankshaft crank 1, the positioning groove 27 passes through the crank pin 3 and the crankshaft crank 1, and a pin shaft 26, a positioning steel ball 28 and a return spring 16 are provided in the positioning groove 27, the pin shaft 26 is bonded to the outer side of the positioning steel ball 28, the inner side of the positioning steel ball abuts the return spring 16, and the inner side of the return spring 16 abuts the bottom of the positioning groove 27, when the return spring is in the return state, the positioning steel ball 28 is located between the crank pin 3 and the crankshaft crank 1 to limit the relative rotation of the crank pin 3 and the crankshaft crank 1.

[0057] The manual driving part 29 is pushed into the square hole opened at the end of the crank pin 3. The manual driving part 29 squeezes the pin shaft 26 to cause radial displacement. The positioning steel ball 28 squeezes the return spring 16 under the push of the pin shaft 26 and completely sinks into the positioning groove 27 on the crank 3. At this time, the crank pin can rotate freely. The lever arm is increased by using tools such as wrenches to manually rotate the driving part to drive the crank pin to rotate. After rotating 180°, there will be a clicking sound under the reaction force of the return spring 16 through the positioning steel ball 29 for positioning. The upper and lower dead point positions of the piston connecting rod 2 are changed, thereby changing the compression ratio; then the manual driving part 29 is pulled out, and the positioning steel ball 28 is stuck in the positioning groove 27 of the crank pin and the crank 3 under the reaction force of the return spring 16, and the crank pin position of part 3 is locked.

Claims

1. An internal combustion engine crankshaft with a variable compression ratio, characterized in that: The internal combustion engine crankshaft is a split crankshaft, comprising a crankpin (3) and a crankshaft crank (1); one end of the crankpin (3) is connected to the crankshaft crank (1) on one side via a driving mechanism, and the other end of the crankpin (3) is connected to the crankshaft crank (1) on the other side via a locking mechanism; the main body of the crankpin (3) and the piston connecting rod (2) matching each other is an eccentric shaft structure; the crankpin (3) is driven to rotate by the driving mechanism, and the rotation angle of the crankpin (3) is locked by the locking mechanism, thereby changing the upper and lower dead point positions of the piston connecting rod (2); The driving mechanism has the same structure as the locking mechanism, and comprises a manual driving part (29) and a driving part connection structure. The driving part connection structure comprises: the crank pin (3) and the crankshaft crank (1) are interference fit, a square hole is provided at the outer end of the crank pin, and the cross-sectional state of the square hole matches the shape of the manual driving part (29); the crank pin (3) and the crankshaft crank (1) are provided with a positioning groove (27), and the positioning groove (27) passes through the crank pin (3) and the crankshaft crank (1). A pin thrust shaft (26), a positioning steel ball (28) and a return spring (16) are arranged in the positioning groove (27); the outer side of the positioning steel ball (28) is bonded to the pin thrust shaft (26); the inner side of the positioning steel ball abuts against the return spring (16); the inner side of the return spring (16) abuts against the bottom of the positioning groove (27); when the return spring is in a return state, the positioning steel ball (28) is located between the crank pin (3) and the crankshaft crank (1) to limit the relative rotation of the crank pin (3) and the crankshaft crank (1); The manual driving part (29) is pushed into the square hole formed at the end of the crank pin (3). The manual driving part (29) squeezes the thrust pin shaft (26) to cause radial displacement. The positioning steel ball (28) is pushed by the thrust pin shaft (26) to squeeze the return spring (16) and completely sink into the positioning groove (27) on the crank. At this time, the crank pin can rotate freely. The driving part is manually rotated by using a wrench to increase the force arm to drive the crank pin to rotate. After rotating 180°, the positioning steel ball makes a clicking sound under the reaction force of the return spring (16) for positioning. The upper and lower dead points of the piston connecting rod change, thereby changing the compression ratio. Subsequently, the manual driving part (29) is pulled out. The positioning steel ball (28) is stuck in the positioning grooves of the crank pin and the crank under the reaction force of the return spring (16), and the crank pin position is locked.

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