WO2024060348A1 - 一种二冲程发动机 - Google Patents

一种二冲程发动机 Download PDF

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Publication number
WO2024060348A1
WO2024060348A1 PCT/CN2022/126847 CN2022126847W WO2024060348A1 WO 2024060348 A1 WO2024060348 A1 WO 2024060348A1 CN 2022126847 W CN2022126847 W CN 2022126847W WO 2024060348 A1 WO2024060348 A1 WO 2024060348A1
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WO
WIPO (PCT)
Prior art keywords
piston
ventilation
valve
crankcase
stroke engine
Prior art date
Application number
PCT/CN2022/126847
Other languages
English (en)
French (fr)
Inventor
李雷夫
Original Assignee
李雷夫
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Filing date
Publication date
Application filed by 李雷夫 filed Critical 李雷夫
Publication of WO2024060348A1 publication Critical patent/WO2024060348A1/zh

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01M—LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
    • F01M13/00—Crankcase ventilating or breathing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—Pistons 
    • F02F3/24—Pistons  having means for guiding gases in cylinders, e.g. for guiding scavenging charge in two-stroke engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01M—LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
    • F01M13/00—Crankcase ventilating or breathing
    • F01M2013/0038—Layout of crankcase breathing systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
    • F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
    • F02B2075/025—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the invention relates to a two-stroke engine.
  • Piston engines in the prior art mainly include four-stroke engines and two-stroke engines.
  • the crankshaft will do one work once after two rotations of the crankshaft; while a two-stroke engine can complete one work once after one rotation of the crankshaft. Therefore, theoretically, when the cylinder volume and speed are the same, the power efficiency of a two-stroke engine is four times. Twice the stroke; in fact, considering various losses, the power efficiency of a two-stroke engine is 1.5 to 1.7 times that of a four-stroke engine; it can be said that a two-stroke engine is a piston reciprocating engine with excellent power density.
  • the traditional two-stroke engine has a ventilation channel on the cylinder wall, so it cannot be equipped with a lubrication system such as an oil ring; this results in the two-stroke engine either mixing gasoline and oil together, or injecting the oil into the crankcase. , and then enter the combustion chamber.
  • a lubrication system such as an oil ring
  • the scavenging port fixed on the cylinder liner is used for air intake and exhaust.
  • the timing of each intake and exhaust only depends on the position of the piston in the cylinder barrel.
  • the intake valve timing cannot be reasonably adjusted according to the actual working conditions, and the overlap angle of the intake and exhaust cannot be adjusted, which ultimately leads to poor efficient combustion in the full speed range.
  • the main purpose of the present invention is to provide a two-stroke engine to overcome many shortcomings of the two-stroke engines in the prior art.
  • the present invention provides a two-stroke engine, which includes:
  • crankcase is fixedly connected to the cylinder block; the outer wall of the crankcase is provided with an air intake passage connected to the internal space of the crankcase and an air intake switch for opening and closing the air intake passage;
  • the piston is installed in the cylinder in a manner that can slide along the inner wall of the cylinder; the piston is connected to the crankshaft in the crankcase through a connecting rod;
  • the cylinder body is located on the side of the piston away from the crankcase to form a combustion chamber; the cylinder body is provided with one or more exhaust passages connected to the combustion chamber and an exhaust switch for opening and closing the exhaust passages;
  • the piston is provided with a ventilation channel and a ventilation valve for opening and closing the ventilation channel.
  • the ventilation channel is connected to the internal space of the combustion chamber and the crankcase respectively; when the air intake switch is opened, the ventilation valve is closed to Complete the air intake of the crankcase; open the ventilation valve at least part of the time when the exhaust switch is opened, and keep the air intake switch closed at all times to complete the exhaust and ventilation of the combustion chamber.
  • a ventilation passage is provided on the piston, and the ventilation passage is opened or closed through ventilation valve control to realize communication between the crankcase and the combustion chamber, thereby achieving periodic ventilation; and
  • the air intake process and the exhaust process are relatively independent, and there will be no exhaust gas residue or fresh gas discharge.
  • the ventilation channel is located on the piston to form a longitudinal air intake effect, which significantly improves the ventilation effect and avoids the air loss of the traditional horizontal intake two-stroke engine, thereby improving the ventilation efficiency and eliminating the need for ventilation due to ventilation. Insufficiency results in poor emissions, poor fuel economy, and low power output, among many other shortcomings.
  • it further includes an injection oil channel system, through which lubricating oil is sprayed onto the inner wall of the cylinder body in some stages when the piston moves upward and/or downward, so as to lubricate the inner wall of the cylinder body and cool and lubricate the piston.
  • an injection oil channel system through which lubricating oil is sprayed onto the inner wall of the cylinder body in some stages when the piston moves upward and/or downward, so as to lubricate the inner wall of the cylinder body and cool and lubricate the piston.
  • the present invention also includes a mechanical restriction part; the mechanical restriction part is configured to actuate the ventilation valve when the piston moves to a predetermined position range, so that the ventilation channel opens; the piston moves to a predetermined position range When outside, the ventilation valve is reset, causing the ventilation channel to close.
  • the predetermined position range is defined in the following manner: the angle of the crankshaft when the piston moves to the bottom dead center position is 0°, the angle when the piston moves downward to abut against the mechanical limiting part is + ⁇ , and the angle when the piston moves upward to separate from the mechanical limiting part is - ⁇ , wherein ⁇ 60°.
  • the ventilation valve is arranged on the piston in a manner that can be pushed out and retracted along the thickness direction of the piston.
  • the interior of the piston is provided with a guide portion that is in sliding fit with the ventilation valve.
  • the ventilation valve has a valve cover, a valve stem and a spring, and the spring is set on the valve stem; the valve cover is arranged on the upper end of the valve stem and is located on the side of the piston close to the combustion chamber; on the valve stem
  • the lower end of the piston is provided with an action part.
  • a cam body is provided on the crankshaft, and the mechanical limiting part is a movable push block; a push rod that can slide along its length direction is provided on the connecting rod, and one end of the push rod is cooperatively connected with the cam body.
  • the movable push block is installed or formed on the other end of the push rod and moves synchronously with the push rod, so that when the piston moves to a predetermined position range, the movable push block and the action part They come into contact with each other, thereby actively opening the valve cover for ventilation.
  • a cam body is provided on the crankshaft, and the mechanical limiting part is a floating piston; a receiving groove is provided on the connecting rod along its length direction, and incompressible oil is injected into the receiving groove; a first opening and a second opening are formed at both ends of the receiving groove, and a pushing piston is provided at the first opening, and the pushing piston is cooperatively connected with the cam body, and the floating piston is sealed at the second opening and can abut against the acting part; when the piston moves to a predetermined position range, a force is applied to the pushing piston through the cam body, and then the floating piston is pushed to abut against the acting part through the oil, thereby actively opening the valve cover for ventilation.
  • the mechanical restriction part is a fixed stop provided on the cylinder or crankcase, and the action part can protrude downward from the piston and be located on the side of the piston close to the crankcase to prevent the piston from moving when the piston moves.
  • the fixed stop is brought into contact with the action part, thereby actively opening the valve cover for ventilation.
  • the ventilation channel on the piston by arranging the ventilation channel on the piston to form a longitudinal air intake mode, the ventilation effect of the combustion chamber is significantly improved; the ventilation valve is used to control the opening or closing of the ventilation channel to realize the connection between the crankcase and the combustion chamber. conduction, thereby achieving periodic ventilation; and the air intake process and the exhaust process are relatively independent, which will not cause the exhaust gas residue and fresh gas to be discharged at the same time. It has the advantages of good ventilation effect and high fuel economy.
  • the ventilation channel and the ventilation valve are arranged inside the piston, and there is no need to make holes on the side of the cylinder inner wall, so that the inner wall of the cylinder can be directly lubricated, avoiding the need for traditional two-stroke engines to mix lubricating oil with
  • FIG1 is an exemplary cross-sectional view of a two-stroke engine
  • FIG2 is a perspective cross-sectional view of a first position of a piston in the exemplary two-stroke engine
  • Figure 3 is a perspective cross-sectional view of a second position of the piston in the exemplary two-stroke engine
  • Figure 4 is a top view of the piston in the exemplary two-stroke engine
  • Figure 5 is another top view of the piston in the exemplary two-stroke engine
  • Figure 6 is a diagram of three position states of the exemplary two-stroke engine in which the piston is located close to the bottom dead center position;
  • Figure 7 is another exemplary cross-sectional view of a two-stroke engine
  • FIG8 is another exemplary cross-sectional view of a two-stroke engine
  • Figure 9 is a top view of the piston in yet another exemplary two-stroke engine.
  • Figure 10 is another top view of the piston in the yet another exemplary two-stroke engine.
  • Figure 1 shows a two-stroke engine configured as a single-cylinder or multi-cylinder engine and used as a power source instead of a conventional two-stroke engine.
  • the two-stroke engine has a cylinder 10, a crankcase 20 and a piston 30; the crankcase 20 and the cylinder 10 are fixedly connected to form the main body of the engine, and the piston 30 is disposed on the cylinder 10 in a manner that can slide along the inner wall of the cylinder 10.
  • the crankcase 20 provides a scavenging chamber 21, and at the same time, there is a certain space inside the crankcase 20 for supplying fresh air; specifically, the outer wall of the crankcase 20 is provided with an air inlet passage 40 connected with the internal space of the crankcase 20 and for
  • the air intake switch 41 opens and closes the air intake passage 40; the air intake switch 41 is preferably a valve-type structure, that is, an intake valve, to better achieve air intake control; in other embodiments, other forms can also be used to achieve air intake control.
  • the air intake switch 41 controlled by air will not be introduced here.
  • the piston 30 is connected to the crankshaft 60 in the crankcase 20 through the connecting rod 50. Under the cooperative driving of the crankshaft 60 and the connecting rod 50, the piston 30 reciprocates in the cylinder 10; the piston 30 is located away from the crankcase 20.
  • a combustion chamber 11 is formed on one side of the combustion chamber, and a spark plug and a high-pressure fuel injector are installed on the top of the combustion chamber 11 to form combustion.
  • the cylinder 10 is provided with an exhaust passage 70 connected with the combustion chamber 11 and an exhaust switch 71 for opening and closing the exhaust passage 70 .
  • the exhaust passage 70 is disposed at the top of the cylinder body 10.
  • the exhaust gas directly enters the exhaust passage 70 and is quickly discharged, so that the exhaust gas can be completely discharged.
  • the inlet of the exhaust passage 70 does not directly contact the piston 30, and does not interfere with the reciprocating motion of the piston 30, so that the cylinder body 10 has a smooth inner wall, so that the inner wall of the cylinder body 10 can be directly lubricated, effectively improving the life of the two-stroke engine.
  • the exhaust switch 71 is preferably a valve structure, i.e., an exhaust valve, to better achieve exhaust control; in other embodiments, other forms of exhaust switches 71 that can achieve exhaust control may also be used, which will not be described in detail here.
  • the number of exhaust switches 71 may be one or more, for example, FIG. 1 shows two exhaust switches 71 to achieve rapid and thorough exhaust.
  • the opening and closing control method of the air intake switch 41 and the exhaust switch 71 in the present invention can adopt the opening and closing control method and structure in the prior art, which will not be introduced here.
  • the piston 30 is provided with a ventilation passage 31 and a ventilation valve 32 for periodically opening and closing the ventilation passage 31.
  • the ventilation passage 31 is connected to the combustion chamber 11 and the crankcase 20 respectively.
  • the internal spaces are connected; wherein, when the air intake switch 41 is opened, the ventilation valve 32 is closed to complete the independent air intake of the crankcase 20; when the exhaust switch 71 is opened, the ventilation valve 32 is opened at least part of the time, and the air intake is maintained.
  • the air switch 41 is always closed, and the fresh air in the crankcase 20 enters the combustion chamber 11 through the ventilation passage 31 to complete the exhaust and ventilation of the combustion chamber 11 .
  • the piston 30 moves down to a position close to the bottom dead center, the combustion chamber 11 is exhausted and ventilated.
  • the ventilation channel 31 is arranged on the piston 30. On the one hand, it can form a longitudinal air intake effect, and the ventilation effect is significantly improved, thereby avoiding the ventilation loss of the traditional two-stroke engine, thereby improving the ventilation efficiency and eliminating many shortcomings such as poor emissions, poor fuel economy and low output power caused by incomplete ventilation; on the other hand, it can maintain the cleanliness of the inner wall of the entire cylinder body 10; in detail, the inlet and outlet of the ventilation channel 31 are both located on the piston 30, so that there is no need to set an air intake hole or an exhaust hole on the inner wall of the cylinder body 10, and the inner wall of the cylinder body 10 does not interfere with the reciprocating motion of the piston 30, so that the inner wall of the cylinder body 10 can be directly lubricated, which effectively improves the life of the two-stroke engine.
  • the two-stroke engine in the present invention also includes an injection oil passage system 80 for lubricating the inner wall of the cylinder 10 .
  • the injection oil passage system 80 lubricates the inner wall of the cylinder 10 through the injection oil passage system 80 .
  • Lubricating oil is sprayed onto the cylinder 10 to lubricate the inner wall of the cylinder 10 and cool and lubricate the piston 30 .
  • the injection oil channel system 80 includes an injection oil channel assembly 81 located on the connecting rod 50 and a piston lubrication cooling oil injection nozzle assembly 82 located on the cylinder block 10 or crankcase 20 .
  • the location of the injection oil channel system 80 There is no interference or other influence on the movement of the piston 30 or the connecting rod 50 .
  • the injection is controlled according to the injection direction and injection frequency of the injection oil channel assembly 81 to inject the lubricating oil into the inner wall of the cylinder 10 in a directional and quantitative manner; the outer circumference of the piston 30 is equipped with an oil ring, and the oil is used when the piston 30 moves downward and upward.
  • the ring scrapes the lubricating oil on the inner wall of the cylinder 10 to form an oil film for lubrication on the inner wall of the cylinder 10 to achieve lubrication protection for the inner wall of the cylinder 10 and the piston 30; in addition, when the piston 30 moves downwards and upwards,
  • the piston lubrication cooling oil injection nozzle assembly 82 is controlled as needed to perform directional and quantitative injection of cooling lubricating oil to cool and lubricate the piston 30 .
  • the injection oil passage system 80 of other structures can also be directly replaced and applied in the above two-stroke engine, and will not be introduced here.
  • the ventilation passage 31 is provided on the piston 30, and the ventilation passage 31 is controlled to open or close through the ventilation valve 32 to realize communication between the crankcase 20 and the combustion chamber 11, thereby achieving periodic ventilation; Moreover, the air intake process and the exhaust process are relatively independent, which will not cause exhaust gas residues and fresh gas to be discharged.
  • the present invention uses a mechanical mechanism to open and close the ventilation valve 32 during the reciprocating motion of the piston 30, so as to accurately control the periodic opening and closing of the ventilation channel 31.
  • the two-stroke engine further includes a mechanical limiter 90 configured to actuate the ventilation valve 32 when the piston 30 moves to be within a predetermined position range, so that the ventilation passage 31 is opened; the piston 30 moves to be outside the predetermined position range. , the ventilation valve 32 automatically resets, causing the ventilation channel 31 to close.
  • the opening structure of the ventilation valve 32 is interconnected with the reciprocating motion of the piston 30.
  • the mechanical restriction part 90 and the ventilation valve 32 cooperate with each other, so that Achieve precise control of the periodic opening and closing of the ventilation channel 31; this action change achieved by mechanical cooperation is of great significance in the engine, and the mechanical cooperation can still maintain an accurate cooperation relationship and perfect reliability during extremely long-term use. Repeatability, it will not be affected by external factors during repeated periodic movements, and can achieve precise control of ventilation volume.
  • the present invention creatively uses the mechanical cooperation formed by the ventilation valve 32 and the mechanical restriction part 90 to control the opening and closing of the ventilation valve 32; the opening of the ventilation valve 32 will not cause fluctuations, and the ventilation valve 32 and the piston 30
  • the sealing reliability is high, and the ventilation volume can be accurately controlled by controlling the opening and duration of the ventilation valve 32 .
  • the predetermined position range of the mechanical restriction part 90 and the piston 30 forming a mechanical fit is defined in the following manner: as shown in FIG. 6 , the angle of the crankshaft 60 when the piston 30 moves to the bottom dead center position is the 0° position, and the piston 30 The angle when the piston 30 moves downward to resist the mechanical restriction part 90 is + ⁇ , and the angle when the piston 30 moves upward to separate from the mechanical restriction part 90 is - ⁇ , where ⁇ 60°.
  • the specific value of ⁇ shown in FIG. 6 is 50°.
  • the size of ⁇ can be adjusted according to design requirements, aiming to ensure that the ventilation valve 32 has sufficient opening time to pass the ventilation valve 32 .
  • the air passage 31 supplies sufficient fresh air into the combustion chamber 11 .
  • the ventilation valve 32 is arranged on the piston 30 in a manner that can be pushed out and retracted along the thickness direction of the piston 30. This can not only ensure the simplicity of the structure of the piston 30, facilitate processing and manufacturing, but also The contact area between the ventilation valve 32 and the piston 30 is reduced, thereby reducing the consumed engine power.
  • the ventilation valve 32 has a valve cover 321 , a valve stem 322 and a spring 323 .
  • the spring 323 is set on the valve stem 322.
  • spring seats 324 are provided at the upper and lower ends of the spring 323, and a locking plate structure 325 is provided at the lower spring seat 324 for assembly;
  • the valve cover 321 is provided at the upper end of the valve rod 322 and is located on the side of the piston 30 close to the combustion chamber 11.
  • the side of the piston 30 close to the combustion chamber 11 preferably has a sealing structure 33 that cooperates with the valve cover 321 to ensure that When the valve cover 321 is in a closed state, a complete sealing effect is achieved.
  • the inclined surface of the valve cover 321 is used to match the two inclined surfaces on the seating surface of the piston 30 that match the above inclined surfaces to form a seal.
  • An action part 326 is provided at the lower end of the valve stem 322.
  • the mechanical restriction part 90 contacts the action part 326, and then drives the valve stem 322 to move through the action part 326; preferably, the action part 326
  • the portion 326 is bowl-shaped, and can also effectively limit the outer circumference of the spring 323 to maintain the effectiveness of the spring 323 when it is compressed.
  • the mechanical restriction part 90 is a movable push block 90a; the crankshaft 60 is provided with a cam body 61. Specifically, the cam body 61 is located on the rotation axis of the crankshaft 60 and the connecting rod 50 and is fixedly arranged in a set direction; the connecting rod 50 is provided with a cam body 61. There is a push rod 51 that can slide along its length direction.
  • the lower end of the push rod 51 is cooperatively connected with the cam body 61 to produce reciprocating sliding under the driving of the cam body 61; the movable push block 90a is installed or formed on the upper end of the push rod 51 And with the synchronous movement of the push rod 51, when the piston 30 moves to a predetermined position range, the movable push block 90a contacts the action part 326, thereby actively opening the valve cover 321 for ventilation.
  • the push rod 51 is arranged on the connecting rod 50 in the form of a slide rail/sliding groove, and the push rod 51 and the cam body 61 form a cam pushing mechanism to realize the extension of the movable push block 90a relative to the connecting rod 50; because the connecting rod 50
  • the upper end of the piston 30 is connected to the piston 30 through a hinged shaft 34 (piston pin), so the relative position distance between the hinged shaft 34 and the piston 30 remains unchanged, and the piston pin has an escape hole formed with the connecting rod 50 and the push rod 51 groove structure to avoid interference.
  • the movable push block 90a is extended, so that the extended movable push block 90a abuts the action part 326 to open the ventilation valve 32, thereby opening the ventilation channel 31 for ventilation.
  • the angular position of the cam body 61 is set to the maximum extension distance of the movable push block 90a, and at the same time, it is determined according to the required extension distance and extension time of the movable push block 90a.
  • the stroke and movement angle of the cam body 61 are used to achieve precise control of the ventilation valve 32.
  • the cam body 61 may have various forms, such as a disc cam, wherein the disc cam may be a cam body 61 with a curved profile, or a cam body 61 with a cam groove; other structures capable of achieving periodic extension and retraction of the push rod 51 are also possible, which are not listed here one by one.
  • a guide portion 35 is provided inside the piston 30 to form a sliding fit with the ventilation valve 32.
  • the guide portion 35 has an upper guide portion 351 and a lower guide portion 352.
  • the upper guide portion 351 is used to guide the valve stem 322, and the lower guide portion 352 is used to guide the action portion 326.
  • the upper guide portion 351 is formed in a straight shape and is located in the middle of the piston 30.
  • An upper guide hole 3511 is provided in the center of the upper guide portion 351 for the valve rod 322 to pass through, and at the same time, the valve rod 322 is guided and limited; the above structure can also place the ventilation valve 32 in the middle of the piston 30 to form a regular Symmetrical structure.
  • the lower guide portion 352 is also formed in a straight shape, and is located directly below the upper guide portion 351 to avoid multiple obstructions to the airflow during ventilation, as shown in Figure 4; of course, when the ventilation is satisfied.
  • the lower guide part 352 can also be arranged in other forms, for example, the lower guide part 352 and the upper guide part 351 are arranged in a cross shape; in addition, the upper guide part 351 and the lower guide part 352 can also be arranged in a cross shape. It can have other forms at the same time, such as the cross type as shown in Figure 5, etc., which will not be listed here.
  • the lower guide portion 352 is provided with a lower guide hole 3521 for the action portion 326 to pass through, and at the same time, the action portion 326 is guided and limited.
  • the cross section of the lower guide hole 3521 may be a circular hole, or a quasi-circular hole formed by multiple arcs.
  • the action portion 326 is preferably always located within the lower guide hole 3521 and does not protrude from the lower guide hole 3521 , in order to maintain long-term motion stability.
  • the upper guide portion 351 and the lower guide portion 352 can be connected as Integrated to form a ventilation channel 31 on opposite sides of the guide portion 35, and open and close simultaneously through the same ventilation valve 32; a sleeve can also be added around the outer periphery of the spring 323 to further reduce the possibility of flow obstruction. The occurrence of turbulence.
  • a specific exemplary periodic motion process of the above structure of the present invention is:
  • the first position i.e., the bottom dead center position
  • the ventilation valve 32 is opened to the maximum position, and the ventilation volume is at the maximum at this time; similarly , the exhaust correspondingly is also the largest.
  • the air intake switch 41 is in a closed state, that is, air intake is not performed.
  • the piston 30 continues to move upward, performing in-cylinder compression until the piston 30 moves to the top dead center position for in-cylinder combustion.
  • the air intake switch 41 is opened in stages to complete complete air intake in the crankcase 20;
  • the active scavenging chamber can be inhaled, the ventilation valve can be opened to realize in-cylinder inhalation, cylinder sealing, in-cylinder compression, in-cylinder combustion, expansion work, piston downward movement and active scavenging chamber inhalation.
  • the ventilation valve can be opened to realize in-cylinder inhalation, cylinder sealing, in-cylinder compression, in-cylinder combustion, expansion work, piston downward movement and active scavenging chamber inhalation.
  • the mechanical restriction part 90 is a floating piston 90b; the connecting rod 50 is provided with an accommodating groove 52 along its length direction, and incompressible oil 53 is injected into the accommodating groove 52; first openings are formed at both ends of the accommodating groove 52 and a second opening.
  • a push piston 54 is provided at the first opening.
  • the push piston 54 is cooperatively connected with the cam body 61.
  • the floating piston 90b is blocked at the second opening; when the piston 30 moves to a predetermined position range, the cam The body 61 exerts force on the pushing piston 54, thereby pushing the floating piston 90b through oil, thereby actively opening the valve cover 321 for ventilation.
  • a rigid rod-like structure formed by the incompressible oil 53, the floating piston 90b and the pushing piston 54 is used to realize the extension and retraction of the floating piston 90b at a specific position, that is, at the connecting rod 50
  • the floating piston 90b is extended, so that the extended floating piston 90b comes into contact with the action part 326 to open the ventilation valve 32, thereby opening the ventilation passage 31 to achieve ventilation.
  • the present invention also provides another specific structure as shown in FIG8 :
  • the mechanical limiter 90 is a fixed stop 90c provided on the cylinder 10 or the crankcase 20 .
  • the action part 326 can protrude downward from the piston 30 and be located on the side of the piston 30 close to the crankcase 20 to prevent the piston 30 from moving to When it is within the predetermined position range, the fixed stopper 90c is in contact with the action part 326, thereby actively opening the valve cover 321 for ventilation.
  • the ventilation valve 32 is preferably provided at the circumferential edge of the piston 30.
  • Each ventilation channel 31 is provided with a ventilation valve 32, and multiple ventilation valves 32 open and close synchronously; as shown in Figures 9-10
  • the number of ventilation channels 32 can be two or four, or it can be three. If the structure allows, it can also be set to more than four; the multiple ventilation channels 32 are preferably centered on the central axis of the piston 30. Distributed in a circular array centered on the center.
  • the structural form and matching form of the ventilation valve 32 are as mentioned above.
  • the blocking structure formed by the fixed stopper 90c can contact the action part 326 at a specific position to open the ventilation valve 32, thereby opening the ventilation channel 31 to achieve ventilation.
  • the ventilation channel 31 is provided on the piston 30 to form a longitudinal air intake mode; at the same time, there is no need to make holes on the side of the inner wall of the cylinder 10, so that the cylinder 10 can be directly
  • the inner wall is lubricated; and the air intake process and the exhaust process are relatively independent, which will not cause the exhaust gas residue and fresh gas to be discharged at the same time. It has the advantages of good ventilation effect, high fuel economy, high lubrication effect and long service life.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Lubrication Details And Ventilation Of Internal Combustion Engines (AREA)
  • Lubrication Of Internal Combustion Engines (AREA)

Abstract

本发明公开了一种二冲程发动机，包括缸体、曲轴箱和活塞；曲轴箱外壁设有与曲轴箱内部空间连通的进气通道和用于启闭进气通道的进气开关；活塞可沿缸体内壁滑动设置在缸体内；活塞通过连杆与曲轴箱内的曲轴连接；缸体内位于活塞远离曲轴箱的一侧形成燃烧室；缸体上设有与燃烧室相连通的排气通道以及用于启闭排气通道的排气开关；活塞上设有换气通道和用于启闭换气通道的换气气门，换气通道分别与燃烧室和曲轴箱的内部空间相连通；在进气开关打开时，换气气门闭合以完成曲轴箱的进气；在排气开关打开时的至少部分阶段开启换气气门，并且保持进气开关始终闭合，以完成燃烧室的排气和换气。本发明具有换气效果好、燃油经济性高和寿命长的优点。

Description

一种二冲程发动机 技术领域
本发明涉及一种二冲程发动机。
背景技术
现有技术中的活塞式发动机主要有四冲程发动机和二冲程发动机。普通的四冲程发动机，曲轴旋转两周才会做功一次；而二冲程发动机只要旋转一周就可以完成一次做功，所以理论上，在气缸容积和转速相同的情况下，二冲程发动机的做功效率是四冲程的两倍；实际上，考虑到各种损失，二冲程发动机的做功效率是四冲程的1.5～1.7倍；可以说，二冲程发动机是一种功率密度优秀的活塞往复式发动机。
然而，随着排放法律法规和油耗经济性指标的日趋严格，传统的二冲程发动机逐步被其他类型发动机所替代，主要有以下原因：
1)独有的换气方式导致的油耗高，由此产生一系列排放问题。
传统的二冲程发动机是依靠新的混合气把废气顶出去，在实际的运行过程中，要么废气排不干净，要么会把干净的混合气一起排出去，由此导致燃烧效率低、排放性能较差等问题，甚至在一些二冲程发动机中还会存在燃烧的混合气进到排气管中，会被炙热的排气管直接点燃，最终导致喷火现象的发生。
2)润滑缺陷导致的发动机寿命低。
传统的二冲程发动机的气缸壁上设有换气通道，因此不能设置油环等润滑系统；这就导致了二冲程发动机要么是把汽油和机油混合在一起，要么是把机油喷射到曲轴箱内，然后再进入燃烧室。上述通过烧机油的方式虽然能够起到一定的润滑，但是润滑效果较差，也会导致发动机的寿命大大缩减。
3)由于传统的二冲程发动机特殊的配气方式，采用固定在缸套上的扫气口进行进气和排气，每次进气和排气的时机只取决于活塞在气缸筒内的位置，无法根据实际工况合理调节进气门时机，也就无法调节进排气的重叠角，最终致使全速域高效燃烧不佳。
发明内容
本发明的主要目的是提供一种二冲程发动机，以克服现有技术中二冲程发动机的诸多不足。
为了实现上述主要目的，本发明提供了一种二冲程发动机，其包括：
缸体；
曲轴箱，与缸体之间固连；曲轴箱外壁设有与曲轴箱内部空间连通的进气通道以及用于启闭进气通道的进气开关；
活塞，以可沿缸体内壁滑动的方式设置在缸体内；活塞通过连杆与曲轴箱内的曲轴连接；
缸体内位于活塞远离曲轴箱的一侧形成燃烧室；缸体上设有与燃烧室相连通的一个或多个排气通道以及用于启闭排气通道的排气开关；
活塞上设有换气通道以及用于启闭换气通道的换气气门，换气通道分别与燃烧室和曲轴箱的内部空间相连通；其中，在进气开关打开时，换气 气门闭合以完成曲轴箱的进气；在排气开关打开时的至少部分阶段开启换气气门，并且保持进气开关始终闭合，以完成燃烧室的排气和换气。
在本发明的上述技术方案中，将换气通道设置在活塞上，通过换气气门控制开启或闭合该换气通道以实现曲轴箱内与燃烧室内的导通，从而实现周期性换气；并且在进气过程和排气过程是相对独立的，不会造成废气残留和新鲜气体的排出。
进一步的，换气通道位于活塞上形成纵向进气效果，换气效果得到明显提升，避免了传统的横置式进气的二冲程发动机的空气损失，从而提高了换气效率，消除了因换气不彻底所导致的排放不佳、燃油经济性差以及输出功率较低等诸多不足。
作为本发明的一种具体实施方式，进一步包括喷射油道系统，活塞上行和/或下行时的部分阶段通过喷射油道系统向缸体内壁上喷入润滑油，以对缸体内壁进行润滑和对活塞进行冷却润滑。
作为本发明的一种具体实施方式，还包括机械限制部；机械限制部构造成在活塞运动至位于预定位置范围内时致动换气气门，使得换气通道打开；活塞运动至位于预定位置范围外时，换气气门复位，使得换气通道闭合。
作为本发明的一种具体实施方式，该预定位置范围以如下方式进行限定：以活塞运动至下止点位置时曲轴的角度为0°位置，活塞下行运动至与机械限制部抵动时的角度为+α，活塞上行运动至与机械限制部分离时的角度为-α，其中，α＜60°。
作为本发明的一种具体实施方式，换气气门以可沿活塞厚度方向推出和退回的方式设置在活塞上。
作为本发明的一种具体实施方式，活塞的内部设有与换气气门形成滑 动配合的导向部。
作为本发明的一种具体实施方式，换气气门具有气门盖、气门杆和弹簧，弹簧套装在气门杆上；气门盖设置在气门杆的上端并位于活塞靠近燃烧室的一侧；在气门杆的下端设有作用部，活塞运动至位于预定位置范围内时，机械限制部与作用部相接触。
作为本发明的一种具体实施方式，曲轴上设有凸轮体，机械限制部为活动推块；连杆上设有可沿其长度方向滑动的推杆，推杆的一端与凸轮体配合连接，以在凸轮体的驱动下产生往复滑动；活动推块安装在或形成在推杆的另一端并随着推杆同步运动，以在活塞运动至位于预定位置范围内时使得活动推块与作用部相抵接，从而主动开启气门盖以进行换气。
作为本发明的一种具体实施方式，曲轴上设有凸轮体，机械限制部为浮动活塞；连杆上设有沿其长度方向的容置槽，容置槽内注入有不可压缩的油液；容置槽的两端形成第一开口和第二开口，第一开口处设有推动活塞，推动活塞与凸轮体配合连接，浮动活塞封堵在第二开口处并能与作用部相抵接；在活塞运动至位于预定位置范围内时，通过凸轮体对推动活塞施加作用力，进而通过油液推动浮动活塞与作用部相抵接，从而主动开启气门盖以进行换气。
作为本发明的一种具体实施方式，机械限制部为设置在缸体或曲轴箱上的固定挡块，作用部能够向下凸伸出活塞并位于活塞靠近曲轴箱的一侧，以在活塞运动至位于预定位置范围内时使得固定挡块与作用部相接触，从而主动开启气门盖以进行换气。
本发明具备以下有益效果：
本发明中，通过将换气通道设置在活塞上，形成纵向进气方式，燃烧室的换气效果得到明显提升；通过换气气门控制开启或闭合该换气通道以 实现曲轴箱内与燃烧室内的导通，从而实现周期性换气；并且在进气过程和排气过程是相对独立的，不会造成废气残留和新鲜气体的同时排出，具有换气效果好、燃油经济性高的优点。
本发明中，换气通道以及换气气门设置在活塞内部，无需在缸体内壁的侧边进行开孔，从而可以直接对缸体内壁进行润滑，避免了传统的二冲程发动机需要将润滑油与燃油混合并燃烧的润滑方式，有效提升了二冲程发动机的寿命。
为了更清楚地说明本发明的目的、技术方案和优点，下面结合附图和具体实施方式对本发明作进一步的详细说明。
附图说明
图1是二冲程发动机示例性的截面图；
图2是该示例性二冲程发动机中活塞的第一位置的立体截面图；
图3是该示例性二冲程发动机中活塞的第二位置的立体截面图；
图4是该示例性二冲程发动机中活塞的一种俯视图；
图5是该示例性二冲程发动机中活塞的另一种俯视图；
图6是该示例性二冲程发动机中活塞位于接近下止点位置的三处位置状态图；
图7是二冲程发动机另一示例性的截面图；
图8是二冲程发动机再一示例性的截面图；
图9是该再一示例性二冲程发动机中活塞的一种俯视图；
图10是该再一示例性二冲程发动机中活塞的另一种俯视图。
具体实施方式
图1示出了一种二冲程发动机，其构造成单缸或多缸发动机并作为动力源代替传统二冲程发动机进行使用。二冲程发动机具有缸体10、曲轴箱20和活塞30；曲轴箱20与缸体10之间固连以形成发动机的主体部分，活塞30以可沿缸体10内壁滑动的方式设置在缸体10内。
曲轴箱20提供扫气室21，同时曲轴箱20的内部具有一定空间以用作补入新鲜空气；具体的，曲轴箱20外壁设有与曲轴箱20内部空间连通的进气通道40以及用于启闭进气通道40的进气开关41；进气开关41优选为气门式结构，即进气气门，以更好地实现进气控制；在其他实施例中，也可以采用其他形式能够实现进气控制的进气开关41，这里不再展开介绍。
活塞30通过连杆50与曲轴箱20内的曲轴60连接，在曲轴60与连杆50的协同驱动下，活塞30在缸体10内进行往复运动；其中活塞30内位于活塞30远离曲轴箱20的一侧形成燃烧室11，燃烧室11的顶部安装有火花塞和高压喷油嘴，以形成燃烧。相应的，在缸体10上设有与燃烧室11相连通的排气通道70以及用于启闭排气通道70的排气开关71。
优选的，排气通道70设置在缸体10的顶部，在排气过程中，废气直接进入排气通道70得以快速排出，以使得废气得以彻底排出。同时在活塞30往复运动过程中，排气通道70的入口不会与活塞30直接接触，不对活塞30的往复运动产生干涉，以使得缸体10具有平滑的内壁，从而可以直接对缸体10内壁进行润滑，有效提升了二冲程发动机的寿命。
排气开关71优选为气门式结构，即排气气门，以更好地实现排气控制；在其他实施例中，也可以采用其他形式能够实现排气控制的排气开关71，这里不再展开介绍。其中，排气开关71的数目可以是一个或多个，例如图 1中示出有两个排气开关71，以实现快速、彻底地排气。
本发明中进气开关41和排气开关71的启闭控制方式可以采用现有技术中的启闭控制方式和结构，这里不再展开介绍。
请继续参阅图1，本发明中在活塞30上设有换气通道31以及用于周期性启闭换气通道31的换气气门32，换气通道31分别与燃烧室11和曲轴箱20的内部空间相连通；其中，在进气开关41打开时，换气气门32闭合以完成曲轴箱20的独立进气；在排气开关71打开时的至少部分阶段开启换气气门32，并且保持进气开关41始终闭合，曲轴箱20内的新鲜空气通过换气通道31进入燃烧室11，以完成燃烧室11的排气和换气。具体的，在活塞30下行至接近下止点位置时，进行燃烧室11的排气和换气。
换气通道31设置在活塞30上，一方面能够形成纵向进气效果，换气效果得到明显提升，避免了传统二冲程发动机的换气损失，从而提高了换气效率，消除了因换气不彻底所导致的排放不佳、燃油经济性差以及输出功率较低等诸多不足；另一方面能够保持整个缸体10内壁的整洁性；展开来说，换气通道31的入口和出口均位于活塞30上，这样就无需在缸体10内壁设置进气孔或排气孔，缸体10内壁不对活塞30的往复运动产生干涉，从而可以直接对缸体10内壁进行润滑，有效提升了二冲程发动机的寿命。
进一步的，本发明中的二冲程发动机还包括用于对缸体10内壁进行润滑的喷射油道系统80，活塞30上行和/或下行时的部分阶段通过喷射油道系统80向缸体10内壁上喷入润滑油，以对缸体10内壁进行润滑和对活塞30进行冷却润滑。
如图1所示，喷射油道系统80包括位于连杆50上的喷射油道组件81和位于缸体10或曲轴箱20上的活塞润滑冷却喷油嘴组件82，喷射油道系统80的位置不对活塞30或者连杆50的运动产生干涉和其他影响。
具体的，根据喷射油道组件81的喷射方向和喷射频率进行控制喷射，以将润滑油定向定量喷射至缸体10内壁上；活塞30的外周套装有油环，活塞30下行和上行时利用油环对缸体10内壁上的润滑油进行刮擦，以在缸体10内壁上形成润滑用的油膜，实现对缸体10内壁以及活塞30的润滑保护；另外，在活塞30下行和上行时，根据需要控制活塞润滑冷却喷油嘴组件82进行冷却润滑油的定向定量喷射，以对活塞30进行冷却润滑。其他结构的喷射油道系统80亦可直接替换并应用在上述二冲程发动机中，这里不再展开介绍。
本发明中将换气通道31设置在活塞30上，通过换气气门32控制开启或闭合该换气通道31以实现曲轴箱20内与燃烧室11内的导通，从而实现周期性换气；并且在进气过程和排气过程是相对独立的，不会造成废气残留和新鲜气体的排出。
进一步的，本发明采用机械机构在活塞30往复运动过程中实现换气气门32的开启和关闭，以精准控制换气通道31的周期性启闭。二冲程发动机还包括机械限制部90，机械限制部90构造成在活塞30运动至位于预定位置范围内时致动换气气门32，使得换气通道31打开；活塞30运动至位于预定位置范围外时，换气气门32自动复位，使得换气通道31闭合。
换气气门32的开启构造为与活塞30的往复运动互相关联，通过活塞30或者与活塞30同步运动的连杆50的运动位置变化，进行机械限制部90与换气气门32的协同配合，从而实现换气通道31周期性启闭的精准控制；这种利用机械配合所实现的动作变化在发动机中具有重要意义，机械配合能够在超长时间使用过程中依旧保持准确的配合关系和完美的可重复性，在重复的周期性运动过程中不会受到外部因素影响，可以实现对换气量的精准控制。
本发明创造性的采用换气气门32和机械限制部90所形成的机械配合， 进行控制换气气门32的开启和闭合；换气气门32的开度不会产生波动，换气气门32与活塞30之间密封的可靠性高，可以通过控制换气气门32的开度和时长，以精准控制换气量。
本发明中机械限制部90与活塞30形成机械配合的预定位置范围以如下方式进行限定：如图6所示，以活塞30运动至下止点位置时曲轴60的角度为0°位置，活塞30下行运动至与机械限制部90抵动时的角度为+α，活塞30上行运动至与机械限制部90分离时的角度为-α，其中，α＜60°。
具体的，图6中所示出的α的具体值为50°，在其他实施例中，可以根据设计需求进行调整α的大小，旨在满足换气气门32具有足够的开启时长，以通过换气通道31向燃烧室11内补入充足的新鲜空气。
为了更为简洁、快速的实现换气，换气气门32以可沿活塞30厚度方向推出和退回的方式设置在活塞30上，这样既可以保证活塞30结构的简洁性，便于加工制造，又可以降低换气气门32与活塞30之间的接触面积，从而降低所消耗的发动机功率。
如图1-3所示，换气气门32具有气门盖321、气门杆322和弹簧323。
弹簧323套装在气门杆322上，为了保持弹簧323有效性，在弹簧323的上下两端均设有弹簧座324，并在位于下方的弹簧座324处设有锁片结构325，以进行装配；
气门盖321设置在气门杆322的上端并位于活塞30靠近燃烧室11的一侧，相应的，在活塞30靠近燃烧室11的一侧优选具有与气门盖321配合的密封结构33，以保证在气门盖321处于闭合形态时，实现完全密封效果。具体的，利用气门盖321自身斜面与活塞30上与上述斜面相适配的着座面上的两个斜面相配合，以形成密封。
在气门杆322的下端设有作用部326，活塞30运动至位于预定位置范 围内时，机械限制部90与作用部326相接触，进而通过作用部326驱动气门杆322进行运动；优选的，作用部326呈碗状，还可以对弹簧323进行有效的外周限位，保持弹簧323被压缩时的有效性。
请再次参阅图1-3，为了实现活塞30往复运动过程中与作用部326形成机械配合，本发明的一种具体结构如下：
机械限制部90为活动推块90a；曲轴60上设有凸轮体61，具体的，凸轮体61位于曲轴60与连杆50配合的回转轴上并以设定方向固定设置；连杆50上设有可沿其长度方向滑动的推杆51，推杆51的下端与凸轮体61配合连接，以在凸轮体61的驱动下产生往复滑动；活动推块90a安装在或形成在推杆51的上端并随着推杆51同步运动，以在活塞30运动至位于预定位置范围内时使得活动推块90a与作用部326相抵接，从而主动开启气门盖321以进行换气。
其中推杆51以滑轨/滑槽的形式设置在连杆50上，推杆51与凸轮体61形成凸轮推动机构，以实现活动推块90a相对于连杆50的伸出；因连杆50的上端与活塞30通过一铰接轴34(活塞销)相连接，故该铰接轴34的位置与活塞30的相对位置距离不变，并且活塞销具有与连杆50、推杆51形成避让的孔槽结构，以避免干涉。在连杆50周期性转动的特定阶段进行活动推块90a的伸出，使伸出的活动推块90a与作用部326相抵接以开启换气气门32，从而打开换气通道31实现换气。
具体的，在活塞30往复运动至下止点位置时，活动推块90a的伸出距离最大进行设置凸轮体61的角度位置，同时根据所需要的活动推块90a的伸出距离和伸出时长确定凸轮体61的行程和运动角，以实现对换气气门32的精准控制。
上述凸轮体61可以具有多种形式，例如采用盘形凸轮，其中盘形凸轮 可以是具有曲线轮廓的凸轮体61形状，也可以是具有凸轮凹槽的凸轮体61形状；其他能够实现推杆51周期性伸出和退回的结构亦可，这里不再一一列举。
进一步的，为了更充分的保证换气气门32开启和闭合操作的稳定性，活塞30的内部设有与换气气门32形成滑动配合的导向部35，导向部35具有上导向部351和下导向部352，上导向部351用于对气门杆322进行导向，下导向部352用于对作用部326进行导向。
如图2-3所示出的立体截面图，为了使换气通道31的具有足够大的换气截面，以保证换气量，上导向部351形成为一字型并位于活塞30的中部，在上导向部351的中央设置有上导向孔3511以供气门杆322穿过，同时对气门杆322进行导向限位；上述结构同时可以将换气气门32置于活塞30的中部，形成规则的对称结构。
同理，下导向部352也形成为一字型，并且下导向部352位于上导向部351的正下方，以避免换气过程中对气流形成多重阻碍，如图4所示；当然在满足换气量或者换气效率的基础上，下导向部352也可以按照其他形式设置，例如将下导向部352和上导向部351呈十字交叉状设置；此外，上导向部351和下导向部352也可以同时具有其他形式，如图5所示出的十字型等等，这里不再一一列举。其中，下导向部352上设有下导向孔3521，以供作用部326穿过，同时对作用部326形成导向限位。
具体的，下导向孔3521的截面可以是圆形孔，也可以是多段弧线所形成的类圆形孔。
在活塞30往复运动过程中，作用部326优选始终位于下导向孔3521内而不会从下导向孔3521穿出，以保持长时间运动的稳定性。
此外，在其他实施例中，在图2-3所示出上下层叠设置的一字型上导向 部351和下导向部352的基础上，可以将上导向部351和下导向部352进行连接为一体，以在导向部35的相对两侧形成换气通道31，并通过同一个换气气门32同时实现启闭；还可以在弹簧323的外周增设套管，以进一步降低因阻流影响所可能出现的湍流现象。
本发明上述结构的一个具体的示例性周期运动过程为：
以图6中的中间图示作为第一位置(即下止点位置)，此时处于排气和换气阶段，即换气气门32开启至最大位置，此时换气量处于最大；同样的，排气相应也为最大。此时，进气开关41处于闭合状态，即不进行进气。
以图6中的右侧图示作为第二位置，此时排气和换气刚好完成，燃烧室11内完全换入新鲜空气。
接着活塞30继续上行，进行缸内压缩，直至活塞30运动至上止点位置处进行缸内燃烧，在这个阶段中阶段性打开进气开关41以完成曲轴箱20内的完全进气；
然后燃料做功，活塞30下行直至图6中左侧图示的第三位置，此时开始进行排气，打开排气开关71；并控制在打开排气开关71之后使得机械限制部90与作用部326抵接以打开换气气门32，进行换气；
最后，活塞30继续下行至下止点位置处，完成一个周期；
上述只是以一个周期运动为例进行介绍，只是为了便于介绍整个过程将下止点位置作为初始位置，应当理解，并非是限制周期开始的初始位置和终止位置。本发明的一个周期内可以实现活扫气室吸气、换气气门打开实现缸内吸气、缸内封闭、缸内压缩、缸内燃烧、膨胀做功、活塞下行和活扫气室吸气的全工作流程。
为了实现活塞30往复运动过程中与作用部326形成机械配合，本发明进一步提供另一种具体结构如图7所示：
机械限制部90为浮动活塞90b；连杆50上设有沿其长度方向的容置槽52，容置槽52内注入有不可压缩的油液53；容置槽52的两端形成第一开口和第二开口，第一开口处设有推动活塞54，推动活塞54与凸轮体61配合连接，浮动活塞90b封堵在第二开口处；在活塞30运动至位于预定位置范围内时，通过凸轮体61对推动活塞54施加作用力，进而通过油液推动浮动活塞90b，从而主动开启气门盖321以进行换气。
具体的，上述结构中，以不可压缩油液53、浮动活塞90b和推动活塞54所形成的类似刚性杆的结构形式，实现在特定位置处浮动活塞90b的伸出和退回，即在连杆50周期性转动的特定阶段进行浮动活塞90b的伸出，使伸出的浮动活塞90b与作用部326相抵接以开启换气气门32，从而打开换气通道31实现换气。
为了实现活塞30往复运动过程中与作用部326形成机械配合，本发明还提供再一种具体结构如图8所示：
机械限制部90为设置在缸体10或曲轴箱20上的固定挡块90c，作用部326能够向下凸伸出活塞30并位于活塞30靠近曲轴箱20的一侧，以在活塞30运动至位于预定位置范围内时使得固定挡块90c与作用部326相接触，从而主动开启气门盖321以进行换气。
其中，换气气门32优选设置在活塞30的周向边缘处，每一换气通道31均设有一个换气气门32，且多个换气气门32同步进行启闭；如图9-10所示，换气通道32的数目可以是两个或四个，也可以是三个，在结构允许情况下，还可以设置为多于四个；多个换气通道32优选以活塞30的中轴线为中心呈圆周阵列分布。
具体的，换气气门32的结构形式以及配合形式如前所述，为了更好地实现换气气门32的作用部326与固定挡块90c形成抵接配合，在不会产生 其他干涉的基础上，根据需要适当增长气门杆322的长度即可，这里不再展开；当然，固定挡块90c也不会对连杆50的运动产生干涉。
具体的，上述结构中，以固定挡块90c所形成的阻挡结构，实现在特定位置处与作用部326相抵接以开启换气气门32，从而打开换气通道31实现换气。
本发明的上述多个实现结构中，均将换气通道31设置在活塞30上，形成纵向进气方式；同时均无需在缸体10内壁的侧边进行开孔，从而可以直接对缸体10内壁进行润滑；并且进气过程和排气过程是相对独立的，不会造成废气残留和新鲜气体的同时排出，具有换气效果好、燃油经济性高、润滑效果高以及寿命长的优点。
虽然本发明以具体实施例揭露如上，但这些具体实施例并非用以限定本发明实施的范围。任何本领域的普通技术人员，在不脱离本发明的发明范围内，当可作些许的变化/修改，即凡是依照本发明所做的同等变化/修改，应为本发明的保护范围所涵盖。

Claims (10)

  1. 一种二冲程发动机，其特征在于，包括：
    缸体；
    曲轴箱，与所述缸体之间固连；所述曲轴箱外壁设有与所述曲轴箱内部空间连通的进气通道以及用于启闭所述进气通道的进气开关；
    活塞，以可沿所述缸体内壁滑动的方式设置在所述缸体内；所述活塞通过连杆与所述曲轴箱内的曲轴连接；
    所述缸体内位于所述活塞远离所述曲轴箱的一侧形成燃烧室；所述缸体上设有与所述燃烧室相连通的一个或多个排气通道以及用于启闭所述排气通道的排气开关；
    所述活塞上设有换气通道以及用于启闭所述换气通道的换气气门，所述换气通道分别与所述燃烧室和所述曲轴箱的内部空间相连通；其中，在所述进气开关打开时，所述换气气门闭合以完成所述曲轴箱的进气；在所述排气开关打开时的至少部分阶段开启所述换气气门，并且保持所述进气开关始终闭合，以完成所述燃烧室的排气和换气。
  2. 如权利要求1所述的二冲程发动机，其特征在于：进一步包括喷射油道系统，所述活塞上行和/或下行时的部分阶段通过所述喷射油道系统向所述缸体内壁上喷入润滑油，以对所述缸体内壁进行润滑和对所述活塞进行冷却润滑。
  3. 如权利要求1所述的二冲程发动机，其特征在于：还包括机械限制部；所述机械限制部构造成在所述活塞运动至位于预定位置范围内时致动所述换气气门，使得所述换气通道打开；所述活塞运动至位于预定位置范 围外时，所述换气气门复位，使得所述换气通道闭合。
  4. 如权利要求3所述的二冲程发动机，其特征在于：该预定位置范围以如下方式进行限定：以所述活塞运动至下止点位置时所述曲轴的角度为0°位置，所述活塞下行运动至与所述机械限制部抵动时的角度为+α，所述活塞上行运动至与所述机械限制部分离时的角度为-α，其中，α＜60°。
  5. 如权利要求3所述的二冲程发动机，其特征在于：所述换气气门以可沿所述活塞厚度方向推出和退回的方式设置在所述活塞上。
  6. 如权利要求5所述的二冲程发动机，其特征在于：所述活塞的内部设有与所述换气气门形成滑动配合的导向部。
  7. 如权利要求5所述的二冲程发动机，其特征在于：所述换气气门具有气门盖、气门杆和弹簧，所述弹簧套装在所述气门杆上；所述气门盖设置在所述气门杆的上端并位于所述活塞靠近所述燃烧室的一侧；在所述气门杆的下端设有作用部，所述活塞运动至位于预定位置范围内时，所述机械限制部与所述作用部相接触。
  8. 如权利要求7所述的二冲程发动机，其特征在于：所述曲轴上设有凸轮体，所述机械限制部为活动推块；
    所述连杆上设有可沿其长度方向滑动的推杆，所述推杆的一端与所述凸轮体配合连接，以在所述凸轮体的驱动下产生往复滑动；所述活动推块安装在或形成在所述推杆的另一端并随着所述推杆同步运动，以在所述活塞运动至位于预定位置范围内时使得所述活动推块与所述作用部相抵接，从而主动开启所述气门盖以进行换气。
  9. 如权利要求7所述的二冲程发动机，其特征在于：所述曲轴上设有凸轮体，所述机械限制部为浮动活塞；
    所述连杆上设有沿其长度方向的容置槽，所述容置槽内注入有不可压缩的油液；所述容置槽的两端形成第一开口和第二开口，所述第一开口处设有推动活塞，所述推动活塞与所述凸轮体配合连接，所述浮动活塞封堵在所述第二开口处；
    在所述活塞运动至位于预定位置范围内时，通过所述凸轮体对所述推动活塞施加作用力，进而通过所述油液推动所述浮动活塞与所述作用部相抵接，从而主动开启所述气门盖以进行换气。
  10. 如权利要求7所述的二冲程发动机，其特征在于：所述机械限制部为设置在所述缸体或所述曲轴箱上的固定挡块；
    所述作用部向下凸伸出所述活塞并位于所述活塞靠近所述曲轴箱的一侧，以在所述活塞运动至位于预定位置范围外时使得所述固定挡块与所述作用部相接触，从而主动开启所述气门盖以进行换气。
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6165013A (ja) * 1984-09-06 1986-04-03 Mitsubishi Heavy Ind Ltd ２サイクルデイ−ゼル機関
DE19705178A1 (de) * 1997-02-11 1998-01-29 Andreas Mozzi Hubkolbenmotor mit Einlaßkanal im Kolben
DE19904004C1 (de) * 1999-02-02 2000-04-20 Udo Wagener Zweitaktmotor
DE19904002A1 (de) * 1999-02-02 2000-08-17 Udo Wagener Zweitaktmotor
WO2012162717A1 (en) * 2011-06-01 2012-12-06 Ocampo Peter Selwyn Air cooled ported piston for internal combustion engines
CN111852650A (zh) * 2020-07-30 2020-10-30 山东交通学院 一种二冲程高膨胀比自由活塞内燃发电机
CN218093231U (zh) * 2022-09-23 2022-12-20 李雷夫 一种二冲程发动机以及动力工具

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6165013A (ja) * 1984-09-06 1986-04-03 Mitsubishi Heavy Ind Ltd ２サイクルデイ−ゼル機関
DE19705178A1 (de) * 1997-02-11 1998-01-29 Andreas Mozzi Hubkolbenmotor mit Einlaßkanal im Kolben
DE19904004C1 (de) * 1999-02-02 2000-04-20 Udo Wagener Zweitaktmotor
DE19904002A1 (de) * 1999-02-02 2000-08-17 Udo Wagener Zweitaktmotor
WO2012162717A1 (en) * 2011-06-01 2012-12-06 Ocampo Peter Selwyn Air cooled ported piston for internal combustion engines
CN111852650A (zh) * 2020-07-30 2020-10-30 山东交通学院 一种二冲程高膨胀比自由活塞内燃发电机
CN218093231U (zh) * 2022-09-23 2022-12-20 李雷夫 一种二冲程发动机以及动力工具

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