An internal combustion engine with varying stroke length cycle and control method

Abstract

The application discloses a different-stroke stroke length cycle change internal combustion engine and a control method, and belongs to the technical field of internal combustion engines. The internal combustion engine comprises at least one cylinder, a piston, a spark plug or an oil nozzle, a stroke displacement mechanism and a valve mechanism. The top of the cylinder is provided with a cylinder head to form a cavity. The valve mechanism comprises an air inlet valve and an air outlet valve on the cylinder head, which are used for supplying air or mixed gas to the cylinder and discharging exhaust gas. The piston reciprocatingly slides in the cavity of the cylinder. The spark plug or the oil nozzle is located on the cylinder head and is used for igniting or injecting oil into the cavity of the cylinder. The stroke displacement mechanism is rotationally connected with the piston through a main connecting rod. The stroke displacement mechanism is rotationally connected with the piston through the main connecting rod and is used for controlling the cycle change of the stroke length of the piston between long and short strokes in the suction, compression, work and exhaust strokes. The four-stroke variable displacement cycle process is realized, the fuel work efficiency is improved, and the exhaust emission index is more optimized.

Description

Technical Field

[0001] This invention belongs to the field of power engineering internal combustion engine technology, and specifically relates to an internal combustion engine with cyclically varying stroke lengths and a control method thereof. Background Technology

[0002] Existing variable displacement engine technology mainly refers to the technology of changing the overall actual displacement of a multi-cylinder piston internal combustion engine by switching cylinders off. This means changing the number of cylinders actually engaged in operation according to the required operating conditions. Typically, to obtain greater power output, the number of cylinders actually engaged in operation is increased, thus increasing the overall actual displacement of the piston internal combustion engine. Conversely, when less power output is needed, the number of cylinders is reduced, thus decreasing the overall actual displacement. For example, an 8-cylinder or 12-cylinder piston internal combustion engine provides very strong power, but at the cost of increased fuel consumption. Especially when high power output is not required, the burned fuel is wasted. Currently, cylinder deactivation variable displacement technology for piston internal combustion engines is considered to effectively solve this problem. Simply put, variable displacement engines control the intake and exhaust valves and fuel supply lines of a piston-type internal combustion engine to open or close one or more cylinders, thereby changing the overall engine displacement and reducing fuel consumption. For example, a 4-cylinder variable displacement engine can automatically switch between 2-cylinder and 4-cylinder operating modes according to actual operating conditions, which can reduce the fuel consumption of the 4-cylinder variable displacement engine and improve the overall fuel economy of the piston-type internal combustion engine.

[0003] General Motors equipped Cadillacs with existing variable displacement engine technology in the 1980s, but the engines often produced significant noise, and the transition from 8 cylinders to 4 cylinders was highly unstable, occasionally getting stuck in a certain state and unable to return to a freely adjustable state. With the development of electromechanical control technology, more precise cylinder switching control will be provided for piston internal combustion engines.

[0004] Ford Motor Company has developed the Variable Displacement Engine (VDE) using state-of-the-art electromechanical control technology, and plans to install this engine in future passenger cars and trucks to improve fuel economy. This engine technology is best suited for use with high-displacement engines. For a 12-cylinder engine, this technology is equivalent to installing two independent 6-cylinder engines, allowing one 6-cylinder engine to operate while the other idles, depending on driving needs. This allows for real-time adjustment of the displacement of the piston-type internal combustion engine, thereby reducing energy consumption.

[0005] Honda's Variable Cylinder Management (VCM) technology for multi-cylinder internal combustion engines allows 3.5-V6 engines to switch between 3-cylinder, 4-cylinder, and 6-cylinder operating modes by shutting down individual cylinders. This enables the overall actual displacement of the multi-cylinder engine to vary between 1.75 and 3.5 liters, thereby significantly saving fuel.

[0006] The Foshan Automotive Innovation Laboratory (vclab) in my country has also developed a technology that controls the overall actual displacement of a piston-type internal combustion engine by controlling the intake air temperature. Based on the principle of air expansion and contraction, when the car is idling or braking, hot air is introduced into the engine through a hot air pipe. Depending on the gasoline octane rating and the need for knock control, air with a temperature range of 100-150 degrees Celsius or even higher can be introduced for combustion. Due to the significant reduction in the density of the intake air, while maintaining an ideal air-fuel ratio, the amount of fuel injected can be significantly reduced through computer control. The significant reduction in intake air density also significantly reduces the energy required to compress air during the compression stroke. Thus, without changing the overall actual displacement of the engine, engine power can be reduced during idling or deceleration, resulting in less fuel injection and lower emissions. This is a method that uses manual control of intake air temperature to control intake air density, indirectly controlling the intake air volume and rapidly changing the air-fuel ratio to reduce fuel injection.

[0007] Current piston-type internal combustion engines, employing lean combustion or stratified combustion, leave oxygen in the exhaust gases, making effective exhaust purification difficult. While non-throttle valve systems offer advantages, their complex intake valve actuation mechanisms result in poor reduction of pumping losses. However, non-throttle valve systems do offer several benefits, such as improved responsiveness and torque output in piston-type internal combustion engines.

[0008] To address the aforementioned issues, variable displacement engines combine the advantages of lean combustion, stratified combustion, and throttle control. Variable displacement adjusts the overall displacement of a piston-type internal combustion engine according to load changes, significantly reducing pumping losses and ensuring a constant air-fuel ratio, thus achieving highly precise exhaust gas purification. Ideally, the overall displacement of a piston-type internal combustion engine should be continuously variable, but this is practically impossible with engines having a limited number of cylinders. However, automotive piston-type internal combustion engines often operate under low-load conditions, so using variable overall displacement to reduce pumping losses remains a highly effective measure.

[0009] Current cylinder deactivation control technologies and variable displacement methods all suffer from a large steep gradient in the overall actual displacement change, affecting the smoothness of piston internal combustion engine operation. Large-scale gradient changes in overall actual displacement cause combustion problems, and the reduction in fuel consumption is not significant. Furthermore, existing variable displacement technologies for piston internal combustion engines suffer from high research, development, manufacturing, and maintenance costs, as well as complex structures, preventing their widespread adoption.

[0010] Strictly speaking, the aforementioned cylinder deactivation technology and thermal expansion technology are not true variable displacement technology. Variable displacement technology should enable each cylinder of a piston-type internal combustion engine to achieve variable displacement control.

[0011] Compression ratio is a crucial parameter affecting the performance of piston-type internal combustion engines. Existing variable compression ratio (VCR) technology refers to changing the cylinder compression ratio within a certain range under different load conditions during normal engine operation, thereby improving the dynamic smoothness of the engine's operation, reducing emissions, and increasing fuel efficiency. In existing piston-type internal combustion engines, gasoline engines typically have a compression ratio of around 8–12, while diesel engines generally have a higher compression ratio, reaching 12–22. Once the piston-type internal combustion engine is determined, the compression ratio is generally fixed. However, a fixed compression ratio cannot fully utilize the performance of a piston-type internal combustion engine. Under low load and low speed conditions, the thermal efficiency of a piston-type internal combustion engine is very low, and a higher compression ratio is preferable. Conversely, under high load and high speed conditions, detonation can easily occur, generating significant mechanical and thermal loads, so a lower compression ratio is preferable. Variable compression ratio can effectively improve engine fuel economy, reduce emissions, and enhance the smoothness of piston-type internal combustion engine operation.

[0012] There are different methods to change the compression ratio of a piston-type internal combustion engine. The common method is to change the distance between the piston's top dead center and the bottom of the cylinder head. Changing the compression ratio usually only changes the position of the piston's top dead center and bottom dead center in the cylinder at the same time. The piston's stroke in the cylinder at the top dead center and bottom dead center does not change. Therefore, changing the compression ratio can only change the piston's position, not its stroke.

[0013] Furthermore, the Saab SVC engine changes the compression ratio by altering the cylinder combustion chamber volume through changes in the piston's position at top dead center, with the compression ratio varying between 8 and 14. The French MCE engine and multi-link VCR engine also change the engine's compression ratio through different methods.

[0014] Therefore, to address the shortcomings of the existing technology, there is a need to provide an internal combustion engine that changes the compression ratio by cyclically varying the stroke length. Summary of the Invention

[0015] In order to at least solve the problem in the prior art that only the compression ratio of the piston internal combustion engine is changed without changing the piston stroke, the present invention provides the following technical solution: an internal combustion engine with cyclically varying stroke lengths, the internal combustion engine comprising: at least one cylinder, a piston, a spark plug or fuel injector, a stroke-displacement mechanism and a valve train mechanism.

[0016] The top of the cylinder is covered with a cylinder head to form a cavity;

[0017] The valve train includes an intake valve and an exhaust valve located on the cylinder head, for supplying air or air-fuel mixture to the cylinder and discharging exhaust gas;

[0018] The piston reciprocates within the cavity of the cylinder;

[0019] The spark plug or the fuel injector is located on the cylinder head and is used to ignite or inject fuel into the cylinder cavity.

[0020] The stroke displacement mechanism is rotatably connected to the piston via a main connecting rod, and is used to control the piston stroke length to cycle between long and short strokes during the intake, compression, power, and exhaust strokes.

[0021] Preferably, the stroke displacement mechanism includes: a main crankshaft, an efficiency crankshaft, the main connecting rod, a sliding shaft connecting rod, and a swing slider;

[0022] One end of the main connecting rod is rotatably connected to the piston, and the other end of the main connecting rod is rotatably connected to the sliding shaft connecting rod;

[0023] The sliding shaft connecting rod is rotatably connected to the main crankshaft;

[0024] The swing slider is mounted on the sliding shaft connecting rod;

[0025] The main crankshaft is mounted on the main crankshaft support body;

[0026] The efficiency crankshaft is rotatably connected to the swing slider, and the efficiency crankshaft swings around the main crankshaft through the efficiency crankshaft support body;

[0027] The main crankshaft is timed relative to the efficiency crankshaft, and the rotation angle of the main crankshaft is twice the rotation angle of the efficiency crankshaft.

[0028] Preferably, an efficiency crankshaft timing wheel is fitted onto the efficiency crankshaft;

[0029] A main crankshaft timing wheel is fitted onto the main crankshaft, and the main crankshaft timing wheel is connected to the efficiency crankshaft timing wheel in a driving relationship.

[0030] The efficiency crankshaft support body has a rotation radius with respect to the distance between the two axes of the main crankshaft and the efficiency crankshaft, and a rotation axis with respect to the axis of the main crankshaft.

[0031] The valve train is mounted on the main crankshaft.

[0032] Preferably, the internal combustion engine further includes: a multi-position locking mechanism, which includes: a locking turntable, a locking disc support, a locking disc limiter, and a handle;

[0033] The locking turntable is mounted on the locking plate support via a locking plate shaft, and the locking turntable is rotatably connected to the ear bracket body located on one side of the efficiency crankshaft support body via a transition support rod.

[0034] The handle is mounted on the locking turntable, and the handle cooperates with the locking disc limiter to lock the angular position of the locking turntable.

[0035] Preferably, the locking disc limiter includes: a locking disc limiter pin, a locking disc limiter spring, and a locking disc limiter sleeve;

[0036] The locking turntable has several limiting slots on its upper edge;

[0037] One end of the locking disc limiter pin is located inside the limit groove;

[0038] The locking disc limiter spring is sleeved outside the locking disc limiter pin;

[0039] The locking disc limiter sleeve is located outside the locking disc limiter pin.

[0040] Preferably, one end of the sliding shaft connecting rod is rotatably connected to the main crankshaft via a main crankshaft sliding shaft connecting rod pin, the middle part of the sliding shaft connecting rod is rotatably connected to the other end of the main connecting rod via a main connecting rod pin, and the other end of the sliding shaft connecting rod is slidably connected to the swing slider;

[0041] The swing slider and the efficiency crankshaft are both located on the same side of the main connecting rod, and the main crankshaft is located on the other side of the main connecting rod;

[0042] The main connecting rod is located between the efficiency crankshaft and the main crankshaft;

[0043] The efficiency crankshaft rotates in the same direction as the main crankshaft.

[0044] Preferably, one end of the sliding shaft connecting rod is rotatably connected to the other end of the main connecting rod via a main connecting rod pin, the middle part of the sliding shaft connecting rod is rotatably connected to the main crankshaft via a main crankshaft sliding shaft connecting rod pin, and the other end of the sliding shaft connecting rod is slidably connected to the swing slider;

[0045] The main crankshaft and the efficiency crankshaft are both located on the same side of the main connecting rod, and the main connecting rod pin is located on the other side of the main connecting rod;

[0046] The main crankshaft is located between the efficiency crankshaft and the main connecting rod;

[0047] The efficiency crankshaft rotates in the opposite direction to the main crankshaft.

[0048] Preferably, the valve train further includes: an intake and exhaust valve rocker back seat, an intake valve rocker back, an exhaust valve rocker back, an intake valve tappet, and an exhaust valve tappet arranged side by side with the intake valve tappet;

[0049] The middle part of the intake valve rocker back is installed on the intake and exhaust valve rocker back seat. One end of the intake valve rocker back is connected to the intake valve, which is fitted with an intake valve spring on the outside. The other end of the intake valve rocker back is rotatably connected to one end of the intake valve push rod.

[0050] The middle part of the exhaust valve backrest is installed on the intake and exhaust valve backrest seat. One end of the exhaust valve backrest is connected to the exhaust valve with an exhaust valve spring sleeved on the outside, and the other end of the exhaust valve backrest is rotatably connected to one end of the exhaust valve push rod.

[0051] Preferably, the valve train further includes: a main crankshaft valve timing wheel, a valve camshaft, a valve camshaft timing wheel, an intake valve cam, and an exhaust valve cam;

[0052] The main crankshaft valve timing wheel is mounted on the main crankshaft;

[0053] The valve timing wheel is located on the outside of the valve camshaft, which is parallel to the main crankshaft, and the valve timing wheel is meshed with the main crankshaft timing wheel;

[0054] The intake valve cam and the exhaust valve cam are set at an angle, and both the intake valve cam and the exhaust valve cam are mounted on the valve camshaft;

[0055] The other end of the intake valve tappet is in contact with the plane of the intake valve cam.

[0056] The other end of the exhaust valve tappet is in contact with the plane of the exhaust valve cam, and both the exhaust valve tappet and the intake valve tappet are fitted with tappet sleeves.

[0057] The present invention also provides a method for controlling the cyclic variation of stroke lengths of different strokes in an internal combustion engine, wherein the control method uses the internal combustion engine according to any one of claims 1-9, and includes the following steps:

[0058] 1) When the piston moves downward from the second top dead center to enter the intake stroke through the main connecting rod of the stroke displacement mechanism, the intake valve opens and the exhaust valve closes, and air or air-fuel mixture enters the cylinder. The piston reaches the first bottom dead center, at which point the piston completes the short stroke L1 of the intake stroke.

[0059] 2) When the piston moves upward from the first bottom dead center to enter the compression stroke, the intake valve and exhaust valve are closed, and the air or mixture is compressed in the cylinder. When the piston reaches the first top dead center, the piston has completed the short stroke L1 of the compression stroke.

[0060] 3) When the piston moves downward from the first top dead center to enter the power stroke, the main connecting rod drives the piston to move downward. The intake valve and exhaust valve are closed. The spark plug or fuel injector ignites or injects fuel into the cylinder. The fuel is ignited and expands to do work. The piston reaches the second bottom dead center. At this time, the piston has completed the long stroke L2 of the power stroke.

[0061] 4) When the piston moves upward from the second bottom dead center to enter the exhaust stroke, the intake valve is closed and the exhaust valve is opened through the main connecting rod. The exhaust gas is discharged from the exhaust valve and the piston reaches the second top dead center. At this time, the piston has completed the long stroke L2 of the exhaust stroke.

[0062] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows:

[0063] 1. This invention, through a stroke displacement mechanism, enables the piston stroke length in the cylinder to cyclically change between long and short strokes, thereby allowing the high-temperature gas in the cylinder to participate in work with more time and space, significantly improving the efficiency of fuel combustion and significantly reducing the actual fuel consumption, effectively improving the fuel economy of the internal combustion engine.

[0064] 2. The internal combustion engine of this invention achieves variable displacement cycle by cyclically changing the stroke between long and short strokes, allowing the combustion gas to obtain more space to expand and do work, resulting in more complete combustion and a significant reduction in the temperature of the gas after work. This not only significantly reduces the temperature of the cylinder exhaust, but also significantly reduces the temperature rise of the internal combustion engine body. It also makes the fuel combustion more complete and significantly reduces the content of harmful gas components in the exhaust gas after fuel combustion. Because the exhaust gas itself is cleaner, the emission indicators are closer to environmental protection requirements.

[0065] 3. The stroke displacement mechanism used in this invention can be combined in two ways: internal support type and external attachment type, depending on the relative positions of the various structures.

[0066] 4. The stroke displacement mechanism used in this invention can easily realize variable compression ratio control of the cylinder piston.

[0067] 5. The exhaust temperature and engine body temperature of the internal combustion engine of the present invention can be significantly reduced, thus significantly reducing the generation of carbon deposits, reducing and simplifying the performance requirements of the cooling system, and making the internal combustion engine's operation more stable.

[0068] 6. This invention can achieve greater power and torque output capabilities with the same intake displacement and fuel consumption of an internal combustion engine.

[0069] 7. This invention proposes a new method that can significantly improve the fuel-mechanical conversion efficiency of internal combustion engines and can be specifically implemented in engineering. Attached Figure Description

[0070] Figure 1 This is a schematic diagram of the structure of an internal combustion engine with cyclically varying stroke lengths according to Embodiment 1 of the present invention;

[0071] Figure 2 This is a schematic diagram showing the position of the piston in the cylinder when the intake stroke is completed in an internal combustion engine with cyclically varying stroke lengths, as provided in an embodiment of the present invention.

[0072] Figure 3 A schematic diagram showing the position of the piston in the cylinder when the compression stroke is completed in an internal combustion engine with cyclically varying stroke lengths, as provided in an embodiment of the present invention.

[0073] Figure 4 This is a schematic diagram showing the position of the piston in the cylinder when the power stroke is completed in an internal combustion engine with cyclically varying stroke lengths, as provided in an embodiment of the present invention.

[0074] Figure 5 A schematic diagram showing the position of the piston in the cylinder when completing the exhaust stroke in an internal combustion engine with cyclically varying stroke lengths, provided as an embodiment of the present invention.

[0075] Figure 6 This is a schematic diagram of the motion change state of the stroke displacement mechanism in an internal combustion engine with cyclically varying stroke lengths during the intake stroke, as provided in Embodiment 1 of the present invention.

[0076] Figure 7 This is a schematic diagram of the motion change state of the stroke displacement mechanism in an internal combustion engine with cyclically varying stroke lengths during the compression stroke, as provided in Embodiment 1 of the present invention.

[0077] Figure 8 This is a schematic diagram of the motion change state of the stroke displacement mechanism in an internal combustion engine with cyclically varying stroke lengths during the power stroke, as provided in Embodiment 1 of the present invention.

[0078] Figure 9 This is a schematic diagram of the motion change state of the stroke displacement mechanism in the exhaust stroke of an internal combustion engine with cyclically varying stroke lengths, as provided in Embodiment 1 of the present invention.

[0079] Figure 10 This is a partial structural schematic diagram of an internal combustion engine with cyclically varying stroke lengths according to Embodiment 2 of the present invention;

[0080] Figure 11 This is a schematic diagram of the motion change state of the stroke displacement mechanism in an internal combustion engine with cyclically varying stroke lengths during the intake stroke, as provided in Embodiment 2 of the present invention.

[0081] Figure 12 This is a schematic diagram of the motion change state of the stroke displacement mechanism in an internal combustion engine with cyclically varying stroke lengths during the compression stroke, as provided in Embodiment 2 of the present invention.

[0082] Figure 13 This is a schematic diagram of the motion change state of the stroke displacement mechanism in an internal combustion engine with cyclically varying stroke lengths during the power stroke, as provided in Embodiment 2 of the present invention.

[0083] Figure 14This is a schematic diagram of the motion change state of the stroke displacement mechanism in the exhaust stroke of an internal combustion engine with cyclically varying stroke lengths, as provided in Embodiment 2 of the present invention.

[0084] In the diagram: 1. Intake and exhaust valve rocker backrest; 2. Intake valve rocker backrest; 3. Exhaust valve rocker backrest; 4. Intake valve spring; 5. Spark plug or fuel injector; 6. Exhaust valve spring; 7. Exhaust valve; 8. Piston pin; 9. Piston; 10. Cylinder; 11. Main connecting rod; 12. Main connecting rod pin; 13. Swing slider; 14. Efficiency crankshaft timing wheel; 15. Ear bracket body; 16. Ear bracket support rod shaft; 17. Transition support rod; 18. Lock disc support rod shaft; 19. Handle; 20. Locking dial; 21. Lock disc shaft; 22. Lock disc support; 23. Lock 24. Disc limiter pin; 25. Disc limiter spring; 26. Disc limiter sleeve; 27. Efficiency crankshaft bracket; 28. Efficiency crankshaft; 29. ​​Swing slider shaft; 30. Drive belt; 31. Sliding shaft connecting rod; 32. Main crankshaft timing wheel; 33. Main crankshaft; 34. Main crankshaft valve timing wheel; 35. Main crankshaft sliding shaft connecting rod pin; 36. Valve camshaft timing wheel; 37. Exhaust valve cam; 38. Valve camshaft; 39. Intake valve cam; 40. Intake valve tappet; 41. Tappet sleeve; 42. Intake valve; 43. Cylinder head. Detailed Implementation

[0085] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0086] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected," "linked," and "set up" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a direct connection or an indirect connection through intermediate components; a wired connection, a radio connection, or a wireless communication signal connection. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0087] Please see Figure 1-14 The present invention provides an internal combustion engine with cyclically varying stroke lengths. The internal combustion engine includes: at least one cylinder 10, piston 9, spark plug 5 or fuel injector, stroke-displacement mechanism and valve train.

[0088] The internal combustion engine of this application can have one or more cylinders 10, the number of which is selected according to actual needs. A cylinder head 42 is mounted on top of the cylinder 10 to form a cavity. The intake valve 41 and exhaust valve 7 in the valve train are both mounted on the cylinder head 42, used to supply air or air-fuel mixture to the cylinder 10 and to exhaust exhaust gases. The piston 9 reciprocates within the cavity of the cylinder 10. The stroke-displacement mechanism is rotatably connected to the piston 9 via a main connecting rod 11, which drives the piston 9 to slide within the cavity of the cylinder 10, forming intake, compression, power, and exhaust strokes with stroke lengths cyclically varying between long and short strokes. Spark plug 5 or fuel injector is installed on cylinder head 42 and is used to ignite or inject fuel into the cavity of cylinder 10 during the power stroke of piston 9. The high-temperature gas generated by the expansion of fuel ignition participates in the work. That is to say, in a four-stroke working cycle, the power stroke is longer than the compression stroke because the high-temperature and high-pressure gas in the power stroke does more work on the piston 9 by displacement. This allows more heat energy to be converted into the mechanical energy of crankshaft rotation in the stroke displacement mechanism, and also allows the combustion gas to have more time and space to burn during the power stroke, thereby changing the gas emission and further reducing the harmful components in the exhaust gas.

[0089] The working principle of an internal combustion engine with cyclically varying stroke lengths: Normally, the piston 9 moves up and down in the cylinder 10 for the same length in all four strokes, resulting in the same displacement for all four strokes. However, the first two strokes of the four-stroke cycle are kept constant, while the strokes of the last two strokes are lengthened. Specifically, the compression and intake strokes of the piston 9 in cylinder 10 have the same short stroke, while the exhaust and power strokes have the same long stroke. This cyclical variation between the two stroke lengths allows the piston 9 moving in cylinder 10 to alternate between two different displacements in a four-stroke working cycle.

[0090] Reference Figure 1 , Figure 6-14As shown, the stroke displacement mechanism described above includes: a main crankshaft 32, an efficiency crankshaft 27, a main connecting rod 11, a sliding shaft connecting rod 30, and a swing slider 13. The main connecting rod 11 is arranged along the length of the cylinder 10 and located within the cavity of the cylinder 10. One end of the main connecting rod 11 is rotatably connected to the piston 9 via a piston pin 8, and the other end of the main connecting rod 11 is rotatably connected to the sliding shaft connecting rod 30 (also called the transverse connecting rod) via a main connecting rod pin 12. Thus, when the sliding shaft connecting rod 30 rotates, the piston 9 can be driven by the main connecting rod 11 to move up and down (reciprocate) within the cavity of the cylinder 10 and enter the four-stroke working cycle. The sliding shaft connecting rod 30 is a horizontal longitudinal rod, and the swing slider 13 is slidably mounted on the sliding shaft connecting rod 30. The connection between the sliding shaft connecting rod 30 and the swing slider 13 is a sliding friction or rolling sliding friction connection. Furthermore, the connection between the swing slider 13 and the sliding shaft connecting rod 30 can also be a rolling sliding shaft hole connection or a rectangular sliding shaft hole connection. The oscillating slider 13 can also be replaced by an oscillating rocker arm, in which case the oscillating rocker arm is rotatably connected to the sliding shaft connecting rod 30 (also called the transverse connecting rod). The sliding shaft connecting rod 30 is rotatably connected to the main crankshaft 32 via the main crankshaft sliding shaft connecting rod pin 34. The main crankshaft 32 is mounted on the main crankshaft support body. The efficiency crankshaft 27 is mounted on the efficiency crankshaft support body 26, and the efficiency crankshaft 27 is rotatably connected to the oscillating slider 13 via the oscillating slider shaft 28. The rotation angle position between the main crankshaft 32 and the efficiency crankshaft 27 has a timing requirement, so that the efficiency crankshaft 27 rotates once for every two rotations of the main crankshaft 32. The efficiency crankshaft 27 can swing around the main crankshaft 32 via the efficiency crankshaft support 26. The efficiency crankshaft 27 simultaneously drives the swing slider 13 to slide along the sliding shaft connecting rod 30. When the main crankshaft 32 rotates, it also drives the sliding shaft connecting rod 30 to rotate. Since the sliding shaft connecting rod 30 is fixedly connected to the main connecting rod 11, when the sliding shaft connecting rod 30 rotates, it also drives the main connecting rod 11 to slide up and down (reciprocate) along the cavity of the cylinder 10 to enter a four-stroke variable displacement cycle.

[0091] To assist the piston 9 in cylinder 10 in alternating between long and short strokes during a four-stroke working cycle, an efficiency crankshaft timing pulley 14 (i.e., an efficiency crankshaft timing toothed pulley) is mounted on the efficiency crankshaft 27, and a main crankshaft timing pulley 31 (i.e., a main crankshaft timing toothed pulley) is mounted on the main crankshaft 32. The main crankshaft timing pulley 31 and the efficiency crankshaft timing pulley 14 are connected in a driving connection. In other words, the timing transmission between the main crankshaft 32 and the efficiency crankshaft 27 is undertaken by a toothed pulley transmission mechanism consisting of the main crankshaft timing pulley 31, the efficiency crankshaft timing pulley 14, and the transmission belt 29. The aforementioned timing transmission can also be accomplished by a sprocket chain or gear pair transmission. A valve train is mounted on the main crankshaft 32. The efficiency crankshaft support 26 has a rotation radius based on the distance between the axes of the main crankshaft 32 and the efficiency crankshaft 27, and a rotation axis based on the axis of the main crankshaft 32. The difference in the rotation diameter angle between the main crankshaft 32 and the efficiency crankshaft 27 will cause the change in the stroke length of the piston 9 in the cylinder to change the position of the top dead center. The timing mechanism, composed of the stroke displacement mechanism, the oscillating slider 13, and the timing toothed belt (referring to the main crankshaft timing wheel 31 and the efficiency crankshaft timing wheel 14), works periodically in coordination with the timing of the valve train.

[0092] When the piston 9 in cylinder 10 is in the four strokes of intake, compression, power, and exhaust, the efficiency crankshaft 27 is in the first, second, third, and fourth positions, respectively. Due to the timing relationship between the main crankshaft 32 and the efficiency crankshaft 27, the main crankshaft 32 is at its highest or lowest point corresponding to the four positions of the efficiency crankshaft 27.

[0093] To ensure the efficient crankshaft 27 is accurately positioned and achieves the specified compression ratio, the piston-type internal combustion engine also includes a multi-position locking mechanism. This mechanism includes a locking disc 20, a locking disc support 22, a locking disc limiter, and a handle 19. The locking disc 20 is mounted on the locking disc support 22 via a locking disc shaft 21 and can rotate along this shaft. The locking disc 20 is rotatably connected to a lug body 15 located on one side of the efficient crankshaft support 26 via a transition rod 17. One end of the transition rod 17 is mounted on the lug body 15 via a lug support rod shaft 16, and the other end is mounted on the locking disc 20 via a locking disc support rod shaft 18. The handle 19 is mounted on the locking disc 20 and cooperates with the locking disc limiter to lock the angular position of the locking disc 20. The operation of the multi-position locking mechanism is as follows: Turning handle 19 causes the locking turntable 20 to rotate around the locking disc shaft 21. Simultaneously, the locking turntable 20 rotates the ear bracket body 15 via the transition support rod 17. The ear bracket body 15 then rotates the fixed efficiency crankshaft support body 26 around the main crankshaft 32. After rotating to a suitable angle, holding handle 19 limits the rotation angle of the locking turntable 20 via the locking disc limiter, thereby limiting the rotation angle of the efficiency crankshaft support body 26. When the efficiency crankshaft support body 26 rotates, it drives the sliding shaft connecting rod 30 to rotate up and down around the main crankshaft 32, causing the top dead center position of the piston 9 driven by the main connecting rod 11 to move up and down for adjustment, thus achieving the purpose of manually controlling and changing the compression ratio.

[0094] Specifically, the locking disc limiter includes: a locking disc limiter pin 23, a locking disc limiter spring 24, and a locking disc limiter sleeve 25. The locking turntable 20 has several limiting slots on its circumference. The locking disc limiter spring 24 is sleeved outside the locking disc limiter pin 23, and the locking disc limiter sleeve 25 is located outside the locking disc limiter pin 23. A slight press on the locking disc limiter sleeve 25 compresses the locking disc limiter spring 24, causing the locking disc limiter pin 23 to pop outward from inside the locking disc limiter sleeve 25, with one end of the locking disc limiter pin 23 inserting into the corresponding limiting slot of the locking turntable 20. The handle 19 cooperates with the locking disc limiter to fix the angular position of the locking turntable 20.

[0095] The aforementioned ear bracket 15 acts as a bridge, connecting the stroke displacement mechanism and the multi-position locking mechanism to achieve the purpose of adjusting the compression ratio in the cylinder 10. The lower part of the ear bracket 15 is arc-shaped; for example, the lower part of the ear bracket 15 is an arc shape that gradually increases from bottom to top.

[0096] Different combinations are formed based on the relative positions of the components in the stroke-displacement mechanism. The first type involves the main crankshaft 32 and the efficiency crankshaft 27 being connected at both ends of the sliding shaft connecting rod 30, with the main connecting rod pin 12 in the middle of the sliding shaft connecting rod 30; this structure is called an internal support type. The second type involves the main crankshaft 32 and the efficiency crankshaft 27 being connected on one side of the sliding shaft connecting rod 30, with the main connecting rod pin 12 on the other side of the sliding shaft connecting rod 30; this structure is called an external mounting type.

[0097] Example 1

[0098] Reference Figure 1 , Figure 6-9 As shown, the characteristics of the internal bearing type are as follows: one end of the sliding shaft connecting rod 30 is rotatably connected to the main crankshaft 32 via the main crankshaft sliding shaft connecting rod pin 34; the middle part of the sliding shaft connecting rod 30 is rotatably connected to the other end (the end away from the piston 9) of the main connecting rod 11 via the main connecting rod pin 12; and the other end of the sliding shaft connecting rod 30 is slidably connected to the swing slider 13. The swing slider 13 and the efficiency crankshaft 27 are both located on the same side of the main connecting rod 11, the main crankshaft 32 is located on the other side of the main connecting rod 11, the main connecting rod 11 is located between the efficiency crankshaft 27 and the main crankshaft 32, and the efficiency crankshaft 27 and the main crankshaft 32 rotate in the same direction.

[0099] Example 2

[0100] Reference Figure 10-14 As shown, the external type features are as follows: one end of the sliding shaft connecting rod 30 is rotatably connected to the other end of the main connecting rod 11 (the end away from the piston 9) via the main connecting rod pin 12; the middle part of the sliding shaft connecting rod 30 is rotatably connected to the main crankshaft 32 via the main crankshaft sliding shaft connecting rod pin 34; and the other end of the sliding shaft connecting rod 30 is slidably connected to the swing slider 13. The main crankshaft 32 and the efficiency crankshaft 27 are both located on the same side of the main connecting rod 11, the main connecting rod pin 12 is located on the other side of the main connecting rod 11, the main crankshaft 32 is located between the efficiency crankshaft 27 and the main connecting rod 11, and the efficiency crankshaft 27 rotates in opposite directions to the main crankshaft 32.

[0101] The difference between Embodiment 1 and Embodiment 2 is that in Embodiment 1, the main connecting rod 11 is connected to the middle of the sliding shaft connecting rod 30, the main crankshaft 32 and the efficiency crankshaft 27 are located on both sides of the main connecting rod 11, and the efficiency crankshaft 27 rotates clockwise. In Embodiment 2, the main connecting rod 11 is connected to one end of the sliding shaft connecting rod 30, the main crankshaft 32 and the efficiency crankshaft 27 are located on the same side of the main connecting rod 11, and the efficiency crankshaft 27 rotates counterclockwise.

[0102] Reference Figure 6-9As shown, during the operation of an internal combustion engine with a cyclically changing stroke length, the piston 9 in cylinder 10 sequentially completes one four-stroke variable displacement cycle. The following explains the motion changes of each structure of the stroke displacement mechanism corresponding to the piston 9 in cylinder 10 during each stroke. It should be noted that the small white dots in the diagram represent different angular phases of the two crankshafts when they rotate to different positions. Solid circles indicate positions at a specific stroke, while hollow circles indicate other stroke positions.

[0103] During the intake stroke, the piston 9 in cylinder 10 moves a short stroke L1 from the second top dead center to the first bottom dead center. The main crankshaft 32 rotates 180° clockwise from its highest point to its lowest point. The efficiency crankshaft 27 rotates 90° clockwise from its first position (left middle point) to its second position (highest point). The sliding shaft connecting rod 30 gradually changes from a horizontal position to an inclined position, thus completing the intake stroke. During the compression stroke, the piston 9 in cylinder 10 moves a short stroke L1 from the first bottom dead center to the first top dead center. The main crankshaft 32 rotates 180° clockwise from its lowest point to its highest point. The efficiency crankshaft 27 rotates 90° clockwise from its second position (highest point) to its third position (right middle point). The sliding shaft connecting rod 30 gradually changes from an inclined position to a horizontal position, thus completing the compression stroke. ， The first top dead center (TDC) of the short stroke L1 is also the first TDC of the long stroke L2. During the power stroke, the piston 9 in cylinder 10 moves a long stroke L2 from the first TDC to the second bottom dead center of the long stroke. The main crankshaft 32 rotates 180° clockwise from its highest point to its lowest point. The efficiency crankshaft 27 rotates 90° clockwise downward from its third position (right middle point) to its fourth position (lowest point). The sliding shaft connecting rod 30 gradually changes from a horizontal position to an inclined position, thus completing the power stroke. During the exhaust stroke, the piston 9 in cylinder 10 moves a long stroke L2 from the second bottom dead center to the second top dead center of the long stroke. The main crankshaft 32 rotates 180° clockwise from its lowest point to its highest point. The efficiency crankshaft 27 rotates 90° clockwise upward from its fourth position (lowest point) to its first position (left middle point). The sliding shaft connecting rod 30 gradually changes from an inclined position to a horizontal position, thus completing the exhaust stroke.

[0104] Reference Figure 11-14As shown, in the operation of an externally mounted internal combustion engine with cyclically varying stroke length, the piston 9 in cylinder 10 sequentially completes one four-stroke variable displacement cycle. The following describes the motion changes of each structure of the stroke displacement mechanism corresponding to the piston 9 in cylinder 10 during each stroke. Although there are some differences in the implementation of externally mounted and internally mounted cyclically varying stroke length piston engines, their working principles and functions for cyclically varying stroke length are the same, and will not be elaborated further here.

[0105] To enable the mechanical opening and closing of the intake valve 41 and the exhaust valve 7, the valve train also includes: intake and exhaust valve rocker back 1, intake valve rocker back 2, exhaust valve rocker back 3, intake valve tappet 39, exhaust valve tappet arranged side by side with the intake valve tappet 39, main crankshaft valve timing wheel 33, valve camshaft 37, valve camshaft timing wheel 35, intake valve cam 38, and exhaust valve cam 36.

[0106] The middle part of the intake valve rocker back 2 is rotatably connected to the intake and exhaust valve rocker back seat 1. One end of the intake valve rocker back 2 is connected to the intake valve 41, which is fitted with an intake valve spring 4 on the outside. The other end of the intake valve rocker back 2 is rotatably connected to the ball head surface at the upper end of the intake valve pusher 39. That is, the intake valve rocker back 2 and the intake valve pusher 39 are linked together to push the intake valve 41 to open and close. The middle part of the exhaust valve rocker back 3 is rotatably connected to the intake and exhaust valve rocker back seat 1. One end of the exhaust valve rocker back 3 is connected to the exhaust valve 7, which is fitted with an exhaust valve spring 6 on the outside. The other end of the exhaust valve rocker back 3 is rotatably connected to the ball head surface at the upper end of the exhaust valve pusher. That is, the exhaust valve rocker back 3 and the exhaust valve 7 are linked together to push the exhaust valve 7 to open and close.

[0107] Furthermore, the main crankshaft timing wheel 33 is mounted on the main crankshaft 32, and is located on one axial side of the main crankshaft timing wheel 31. Thus, when the main crankshaft timing wheel 31 rotates, it can drive the main crankshaft timing wheel 33 to rotate via the main crankshaft 32. The camshaft timing wheel 35 is located above the main crankshaft timing wheel 33, outside the camshaft 37. The camshaft 37 is parallel to the main crankshaft 32, and the camshaft timing wheel 35 meshes with the main crankshaft timing wheel 33, meaning the main crankshaft timing wheel 33 can drive the camshaft timing wheel 35 to rotate. The intake valve cam 38 and exhaust valve cam 36 are set at an angle, for example, 90°. Both the intake valve cam 38 and the exhaust valve cam 36 are mounted on the camshaft 37. When the timing wheel 35 of the camshaft rotates, it drives the intake valve cam 38 or the exhaust valve cam 36 to rotate via the camshaft 37. The flat end of the lower end of the intake valve tappet 39 is fixedly mounted on one side of the intake valve cam 38, which pushes the intake valve tappet 39 upward. The upward movement of the intake valve tappet 39 pushes one end of the intake valve rocker back 2 upward through the spherical surface, causing the other end of the intake valve rocker back 2 (the end closer to the piston 9) to move downward. The intake valve spring 4 is compressed, thereby opening the intake valve 41; conversely, the intake valve 41 is closed. The flat end of the lower end of the exhaust valve tappet is fixedly mounted on one side of the exhaust valve cam 36, which pushes the exhaust valve tappet upward. Both the exhaust valve tappet and the intake valve tappet 39 are fitted with tappet sleeves 40. When the exhaust valve tappet moves upward, it pushes one end of the exhaust valve backrest 3 upward through the spherical surface, thereby causing the other end of the exhaust valve backrest 3 (the end closer to the piston 9) to move downward. The exhaust valve spring 6 is compressed, thereby opening the exhaust valve 7. Conversely, the exhaust valve 7 is closed.

[0108] Reference Figure 2-5 As shown, the present invention also provides a method for controlling the cyclic variation of the stroke length of an internal combustion engine in different strokes. This control method uses the aforementioned internal combustion engine and includes the following steps:

[0109] 1) When the stroke displacement mechanism drives the piston 9 to move downward from the second top dead center to enter the intake stroke through the main connecting rod 11, the intake valve 41 opens and the exhaust valve 7 closes, and air or mixture enters the cylinder 10. The piston 9 reaches the first bottom dead center. At this time, the piston 9 has completed the short stroke L1 of the intake stroke.

[0110] 2) When the piston 9 moves upward from the first bottom dead center to enter the compression stroke through the main connecting rod 11, the intake valve 41 and the exhaust valve 7 are both closed, and the air or mixture is compressed in the cylinder 10. The piston 9 reaches the first top dead center. At this time, the piston 9 has completed the short stroke L1 of the compression stroke.

[0111] 3) When the piston 9 moves downward from the first top dead center to enter the power stroke through the main connecting rod 11, the intake valve 41 and the exhaust valve 7 are both closed. The spark plug 5 or the fuel injector ignites or injects fuel into the cylinder 10. The fuel is ignited and expands to do work. The piston 9 reaches the second bottom dead center of the long stroke. At this time, the piston 9 has completed the long stroke L2 of the power stroke.

[0112] 4) When the piston 9 moves upward from the second bottom dead center of the long stroke to enter the exhaust stroke through the main connecting rod 11, the intake valve 41 is closed and the exhaust valve 7 is opened. The exhaust gas is discharged from the exhaust valve 7 and the piston 9 reaches the second top dead center of the long stroke. At this time, the piston 9 has completed the long stroke L2 of the exhaust stroke.

[0113] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this invention or its equivalents are included in this invention.

Claims

1. An internal combustion engine with cyclically varying stroke lengths, characterized in that, The internal combustion engine includes: at least one cylinder, piston, spark plug or fuel injector, stroke-displacement mechanism, multi-position lock-up mechanism and valve train. The top of the cylinder is covered with a cylinder head to form a cavity; The valve train includes an intake valve and an exhaust valve located on the cylinder head, for supplying air or air-fuel mixture to the cylinder and discharging exhaust gas; The piston reciprocates within the cavity of the cylinder; The spark plug or the fuel injector is located on the cylinder head and is used to ignite or inject fuel into the cylinder cavity. The stroke displacement mechanism is rotatably connected to the piston via a main connecting rod, and is used to control the piston stroke length to cycle between long and short strokes during the intake, compression, power and exhaust strokes; The stroke displacement mechanism includes: a main crankshaft, an efficiency crankshaft, the main connecting rod, a sliding shaft connecting rod, and a swing slider; One end of the main connecting rod is rotatably connected to the piston, and the other end of the main connecting rod is rotatably connected to the sliding shaft connecting rod; The sliding shaft connecting rod is rotatably connected to the main crankshaft; The swing slider is mounted on the sliding shaft connecting rod; The main crankshaft is mounted on the main crankshaft bracket, and the valve train is mounted on the main crankshaft; The efficiency crankshaft is rotatably connected to the swing slider, and the efficiency crankshaft swings around the main crankshaft through the efficiency crankshaft support body; The main crankshaft is timed relative to the efficiency crankshaft, and the rotation angle of the main crankshaft is twice the rotation angle of the efficiency crankshaft. An efficiency crankshaft timing wheel is fitted onto the efficiency crankshaft; A main crankshaft timing wheel is fitted onto the main crankshaft, and the main crankshaft timing wheel is connected to the efficiency crankshaft timing wheel in a driving relationship. The efficiency crankshaft support body has a rotation radius with respect to the distance between the two axes of the main crankshaft and the efficiency crankshaft, and a rotation axis with respect to the axis of the main crankshaft. The multi-position locking mechanism includes: a locking turntable, a locking disc support, a locking disc limiter, and a handle; The locking turntable is mounted on the locking plate support via a locking plate shaft, and the locking turntable is rotatably connected to the ear bracket body located on one side of the efficiency crankshaft support body via a transition support rod. The handle is mounted on the locking turntable, and the handle cooperates with the locking turntable limiter to lock the corner position of the locking turntable; The swing slider and the efficiency crankshaft are both located on the same side of the main connecting rod, and the main crankshaft is located on the other side of the main connecting rod. The efficiency crankshaft and the main crankshaft rotate in the same direction.

2. The internal combustion engine with cyclically varying stroke lengths according to claim 1, characterized in that, The locking disc limiter includes: a locking disc limiter pin, a locking disc limiter spring, and a locking disc limiter sleeve; The locking turntable has several limiting slots on its upper edge; One end of the locking disc limiter pin is located inside the limit groove; The locking disc limiter spring is sleeved outside the locking disc limiter pin; The locking disc limiter sleeve is located outside the locking disc limiter pin.

3. The internal combustion engine with cyclically varying stroke lengths according to claim 1, characterized in that, One end of the sliding shaft connecting rod is rotatably connected to the main crankshaft via a main crankshaft sliding shaft connecting rod pin, the middle part of the sliding shaft connecting rod is rotatably connected to the other end of the main connecting rod via a main connecting rod pin, and the other end of the sliding shaft connecting rod is slidably connected to the swing slider; The main connecting rod is located between the efficiency crankshaft and the main crankshaft.

4. The internal combustion engine with cyclically varying stroke lengths according to claim 1, characterized in that, The valve train also includes: an intake and exhaust valve rocker back seat, an intake valve rocker back, an exhaust valve rocker back, an intake valve tappet, and an exhaust valve tappet arranged side by side with the intake valve tappet; The middle part of the intake valve rocker back is installed on the intake and exhaust valve rocker back seat. One end of the intake valve rocker back is connected to the intake valve, which is fitted with an intake valve spring on the outside. The other end of the intake valve rocker back is rotatably connected to one end of the intake valve push rod. The middle part of the exhaust valve backrest is installed on the intake and exhaust valve backrest seat. One end of the exhaust valve backrest is connected to the exhaust valve with an exhaust valve spring sleeved on the outside, and the other end of the exhaust valve backrest is rotatably connected to one end of the exhaust valve push rod.

5. The internal combustion engine with cyclically varying stroke lengths according to claim 4, characterized in that, The valve train also includes: a main crankshaft valve timing wheel, a valve camshaft, a valve camshaft timing wheel, an intake valve cam, and an exhaust valve cam; The main crankshaft valve timing wheel is mounted on the main crankshaft; The valve timing wheel is located on the outside of the valve camshaft, which is parallel to the main crankshaft, and the valve timing wheel is meshed with the main crankshaft timing wheel; The intake valve cam and the exhaust valve cam are set at an angle, and both the intake valve cam and the exhaust valve cam are mounted on the valve camshaft; The other end of the intake valve tappet is in contact with the plane of the intake valve cam. The other end of the exhaust valve tappet is in contact with the plane of the exhaust valve cam, and both the exhaust valve tappet and the intake valve tappet are fitted with tappet sleeves.

6. A method for controlling the cyclic variation of stroke lengths in different strokes of an internal combustion engine, characterized in that, The method uses the internal combustion engine according to any one of claims 1-5 and includes the following steps: 1) When the piston moves downward from the second top dead center to enter the intake stroke through the main connecting rod of the stroke displacement mechanism, the intake valve opens and the exhaust valve closes, and air or air-fuel mixture enters the cylinder. The piston reaches the first bottom dead center, at which point the piston completes the short stroke L1 of the intake stroke. 2) When the piston moves upward from the first bottom dead center to enter the compression stroke, the intake valve and exhaust valve are closed, and the air or mixture is compressed in the cylinder. When the piston reaches the first top dead center, the piston has completed the short stroke L1 of the compression stroke. 3) When the piston moves downward from the first top dead center to enter the power stroke, the main connecting rod drives the piston to move downward. The intake valve and exhaust valve are closed. The spark plug or fuel injector ignites or injects fuel into the cylinder. The fuel is ignited and expands to do work. The piston reaches the second bottom dead center. At this time, the piston has completed the long stroke L2 of the power stroke. 4) When the piston moves upward from the second bottom dead center to enter the exhaust stroke, the intake valve is closed and the exhaust valve is opened through the main connecting rod. The exhaust gas is discharged from the exhaust valve and the piston reaches the second top dead center. At this time, the piston has completed the long stroke L2 of the exhaust stroke.

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