TWI825061B - A rotary valve internal combustion engine - Google Patents

Abstract

A rotary valve internal combustion engine has a piston 1 connected to a crankshaft 3 and reciprocatable in a cylinder 2, a combustion chamber 4 being defined in part by the piston. The engine has a rotary valve 5 rotatable in a valve housing 8 fixed relative to the cylinder 2, the rotary valve having a valve body containing a volume 9 defining, in part, the combustion chamber 4 and further having in a wall part 11 thereof a port 12 giving, during rotation of the valve, fluid communication successively to and from the combustion chamber via inlet and exhaust ports 13, 14 in the valve housing. The valve body has a non-uniform radial profile along its axial length and/or about its axis of rotation to accommodate changes in the profile of the valve body during operation.

Description

Rotary valve internal combustion engine

The present invention relates to a rotary valve internal combustion engine, in which the control of air intake and exhaust of the internal combustion engine is accomplished by a rotary valve.

Such rotary valves are known, for example in Applicant's Patent No. GB 2467947B. Conventional rotary valve internal combustion engines have sealing problems due to conflicts in minimizing the gap between counter-rotating bodies, which improves efficiency. , but increases the risk of overheating and jamming. There have been attempts over the years to use rotary valves to make commercially acceptable internal combustion engines, notably Aspin, but these engines have been mostly unsuccessful. In the prior art, for example the two patent cases DE 4217608 A1 and DE 4040936 A1, the above dilemma is noted and attempts are made to solve the problem by providing complex cooling devices or simply by using suitable materials. In practice, providing greater than desired clearance to reduce the risk of seizing comes at the cost of reduced efficiency of the internal combustion engine and increased emissions, which creates difficulties in meeting current regulations and customer expectations.

The existing problem of reduced clearance due to differential thermal expansion between the rotary valve body and the valve cover arises from the fact that the rotary valve body reaches a higher temperature in part relative to the valve cover. This is partly due to the fact that the valve system is located where the highest temperatures are generated in the combustion chamber and has a poor thermal path through which it conducts heat to the outside world. In contrast, this valve housing has the advantage of being able to conduct heat directly through the supply of external cooling means (eg fins or water cooling).

The present invention attempts to provide a means to overcome known problems.

The present invention provides a rotary valve internal combustion engine, including a piston connected to a crankshaft and capable of double reciprocation in a cylinder having a combustion end, and a combustion chamber partially defined by the piston and the combustion end of the cylinder. , a valve cover, fixed to the outside of the combustion end of the cylinder and defining a hole in the hole of the valve cover and a substantially cylindrical rotary valve that rotates along the rotary valve axis with a tight sliding fit, and the rotary valve has a hollow valve body , the hollow valve body has an inner volume that forms a part of the combustion chamber, wherein the inner volume of the hollow valve body accommodates combustion gases during the combustion process, and further has an interface in its wall portion for use when the valve rotates. The valve cover provides liquid flow sequentially from and to the combustion chamber through input and discharge interfaces, performing a sealing function between the surface of the rotary valve body and an adjacent surface of the hole in the valve cover, in which only The sealing function is performed on the surface of the rotary valve body and on the surface of the valve cover without additional sealing means between the rotary valve and the valve cover, wherein the valve body has along its axial length and/or its axis of rotation Non-uniform radial profile to accommodate changes in body profile during operation.

In a preferred embodiment, the diameter of the valve body at the open end of the combustion chamber gradually decreases along its axial extent so that it is smaller than the diameter at the end away from the combustion chamber to adapt to the contour of the valve body during operation. changes.

The valve body may be frustoconical in shape along its length.

In another embodiment, the valve body is contoured to accommodate changes in temperature gradients produced along the valve body during operation.

Preferably, in another embodiment, the valve has a concentric drive shaft mounted in the valve housing to allow slight radial movement of the valve in the valve housing so that the valve acts as an actively sealing valve.

In this embodiment, the end of the valve drive shaft adjacent the valve body has a reduced diameter to allow slight radial movement of the valve in the valve housing.

Preferred embodiments of the present invention will be described below with reference to the drawings.

1:piston

2:Cylinder

3: Crankshaft

4: Combustion chamber

5: Rotary valve

5a:shaft

6:Concentric drive shaft

7:Single roller ball bearing

8: Valve cover

9: Driven gear

10:Driving gear

11: Drive components

12: Drive shaft

13:Lower bearing

24:Crankcase

14:shoulder

15,16: Helical gear

17:Pipeline

18: Upper bearing

19: Valve body

20: Volume

21:Interface

22: Lower perimeter

23: wall

Figure 1 shows a cross-sectional view of a single-cylinder air-cooled internal combustion engine.

Figure 2 shows a schematic diagram of the rotary valve body according to an embodiment.

Figure 1 shows a single-cylinder air-cooled internal combustion engine. The internal combustion engine has a cylinder cover including the cylinder 2 . A piston 1 is connected in a conventional manner to a crankshaft 3 that rotates in a crankcase 24 and can travel back and forth in the cylinder 2 . The upper part of the cylinder 2 is enclosed by a combustion chamber 4 with a combustion chamber cover. A rotary valve 5 controls the flow of mixed air/fuel and exhaust gases into and out of the combustion chamber 4 . In this embodiment, the valve 5 can rotate along an axis 5a coaxial with the cylinder 2 in a valve cover 8 in the combustion chamber cover. In other embodiments, the rotation axis of the valve body is offset from the axis 5a of the cylinder 2 .

At one end away from the combustion chamber 4, the rotary valve 5 has a concentric drive shaft 6 with a single-race ball bearing 7 to rotatably support the rotary valve 5 in the valve cover 8. The concentric driving shaft 6 of the rotary valve 5 is fixed to a coaxial driven gear 9, which meshes with the driving gear 10 of a driving member 11, so that the driven gear 9 and the rotary valve 5 are connected to The crankshaft 3. The drive member 11 includes a drive shaft 12 located in a channel or line 17 of the cylinder cover, arranged for rotation on an upper bearing 18 adjacent the drive gear 10 and a lower bearing 13 adjacent the crankshaft 3 . The driving member 11 has a helical gear 15 which is meshed and fixed to a corresponding helical gear 16 of the crankshaft and rotates together with the crankshaft 3 . Therefore, the rotation of the crankshaft 3 and the movement of the piston can be coordinated by the rotation of the rotary valve 5, so that the internal combustion engine operates with a conventional four-stroke cycle. In order to achieve the above purpose, the diameter of the driven gear 9 should be twice that of the driving gear 10, so the rotation speed of the rotary valve 5 is half of that of the internal combustion engine.

Figure 2 reveals the details of the rotary valve 5. The rotary valve 5 includes a substantially cylindrical rotary valve body 5, which can rotate along a rotary valve axis 5a and has a tight sliding fit in the hole of the valve cover 8. The rotary valve 5 5 has a hollow valve body with an internal volume forming part of the combustion chamber. The valve has a substantially cylindrical body part, including the valve body 19 with an inner diameter slightly larger than that of the concentric drive shaft 6, forming a shoulder 14 with respect to which the rolling ring of the single-roller ball bearing 7 is disposed. The valve body 19 extends into the combustion chamber and has in its interior a volume 20 that forms part of the combustion chamber 4 and contains the combustion gases during all stages of the combustion process. The valve body 19 can rotate in a hole in the valve cover 8 and has a tight sliding fit. The valve body has a non-uniform radial profile along its axial length and/or its axis of rotation to accommodate changes in the valve body profile during operation. In this embodiment, the diameter of the valve body is gradually reduced and has a smaller diameter at the bottom end of the valve body adjacent to the drive shaft 12. The tapered structure is designed to compensate for the use of the valve body along its length. The directional differential expansion is primarily caused by the temperature gradient that actually occurs along the length of the valve body. The valve 5 and the valve cover 8 are formed of aluminum.

The concentric drive shaft 6 is part of the rotary valve 5 and has a diameter only slightly smaller than the valve body 19 to provide the shoulder 14 . The shaft is solid to provide a good path for heat conduction from the valve body 19 to the outside. Adjacent to the shoulder 14, the concentric drive shaft 6 has a slight undercut, allowing a slight radial movement of the valve body, so that during the combustion phase, when combustion pressure is high, the valve interface is biased towards the outlet of the valve housing interface, allowing the valve to act as an active seal and reduce gas leakage.

The rotary valve body 19 has an interface 21, which can sequentially allow liquid to flow from and to the internal volume of the valve when the valve rotates, so that it can flow through the combustion chamber air inlet and exhaust interface of the valve cover. In this embodiment, the interface 21 is in the form of a recess formed on the lower periphery 22 of the valve body wall 23 adjacent to the combustion chamber 4. The recess extends upward from the lower periphery of the valve body wall to form the valve body. Interface 21 on one side.

In this embodiment, the contour of the valve body is uneven and the valve body rotates in a uniform cylindrical hole in the valve cover. In another structure, the contour of the valve body can be uniform cylindrical. The valve cover has an uneven shape formed in the hole.

Although the above is a single-cylinder internal combustion engine, it should be understood that the present invention is also applicable to a multi-cylinder internal combustion engine, which can be an in-line, V-shaped or horizontally opposed structure. In addition, although the above is a spark ignition internal combustion engine, the present invention is also applicable to a compression ignition internal combustion engine.

Although the example given herein is for an internal combustion engine in which the rotary axis of the rotary valve is coaxial or parallel, it will be understood that the axis of rotation of the valve may be angularly offset from the axis of the cylinder. The invention is equally applicable to rotary valve internal combustion engines in which the axis of rotation of the valve is parallel to the axis of rotation of the crankshaft, or indeed at any intermediate angle.

1:piston

2:Cylinder

3: Crankshaft

4: Combustion chamber

5: Rotary valve

5a:shaft

6:Concentric drive shaft

7:Single roller ball bearing

8: Valve cover

9: Driven gear

10:Driving gear

11: Drive components

13:Lower bearing

14:shoulder

15,16: Helical gear

17:Pipeline

Claims (6)

A rotary valve internal combustion engine, including: a piston connected to a crankshaft and reciprocating in a cylinder, the cylinder having a combustion end, a combustion chamber partially defined by the piston and the combustion end of the cylinder, a valve cover fixed Defining a hole outside the combustion end of the cylinder and in the hole of the valve cover and a rotary valve with a tight sliding fit that rotates along the rotary valve axis, the rotary valve has a hollow valve body, the hollow valve body has an internal volume , forming a part of the combustion chamber, in which the inner volume of the hollow valve body accommodates combustion gases during the combustion process, and further has an interface in its wall portion for input and exhaust in the valve cover when the valve rotates. The interface provides liquid flow sequentially from and to the combustion chamber, performing a sealing function between the surface of the rotary valve body and an adjacent surface of the hole in the valve cover, wherein only the surface of the rotary valve body and the The surface of the valve housing performs this sealing function without additional sealing means between the rotary valve and the valve housing, wherein the hollow valve body has an uneven radial profile along its axial length and/or its axis of rotation to Adapting to changes in the contour of the hollow valve body during operation, wherein the contour of the valve body is determined to accommodate changes in the temperature gradient generated along the valve body during operation. The rotary valve internal combustion engine described in item 1 of the patent application, wherein the diameter of the valve body at the opening end of the combustion chamber gradually decreases along its axial range, making it smaller than the diameter away from the end of the combustion chamber, to accommodate changes in the valve body contour during operation. For the rotary valve internal combustion engine described in item 1 or 2 of the patent application, the valve body has a frustoconical shape along its length direction. The rotary valve internal combustion engine as described in item 1 or 2 of the above patent application, wherein the valve has a concentric drive shaft installed in the valve cover to allow the valve to move slightly radially in the valve cover, so that This valve acts as an actively sealing valve. The rotary valve internal combustion engine as described in item 3 of the above patent application, wherein the valve has a concentric drive shaft installed in the valve cover to allow the valve to move slightly radially in the valve cover, so that the valve acts as a Active sealing valve. The rotary valve internal combustion engine of claim 4, wherein the end of the concentric drive shaft adjacent to the valve body has a reduced diameter to allow the valve to move slightly radially in the valve housing.