TW202010927A - A rotary valve internal combustion engine - Google Patents

Abstract

A spark ignition rotary valve internal combustion engine comprising a combustion chamber being defined in part by the piston and the combustion end of the cylinder, a valve housing fixed at an outer portion of the combustion end of the cylinder and defining a bore and a rotary valve rotatable about a rotary valve axis in the bore in the valve housing, the rotary valve having a hollow valve body subjected to combustion gases throughout the combustion process, and further having in a wall part thereof a port giving, during rotation of the valve, fluid communication successively to and from the combustion chamber via inlet and exhaust ports in the valve housing. The inlet and exhaust ports are angularly offset with respect to a radial line from the centre of the engine cylinder.

Description

Rotary valve internal combustion engine

The invention relates to a rotary valve internal combustion engine, especially but not limited to a handheld machine, such as a gardening handheld long-handed weeder or hedge trimmer, wherein the control of the intake and exhaust of the internal combustion engine is by a rotation Valve reached.

A rotary valve internal combustion engine includes: a piston connected to a crankshaft and capable of reciprocating movement in a cylinder, the cylinder has a combustion end; a combustion chamber, the piston and the combustion end of the cylinder constitute a part of the combustion chamber A valve cover, fixed outside the combustion end of the cylinder, and forming a hole and a rotary valve, the rotary valve can rotate along a rotary valve shaft of the hole in the valve cover, the rotary valve has a hollow valve body, The hollow valve body has an internal volume forming part of the combustion chamber, wherein the internal volume of the hollow valve body contains combustion gas throughout the combustion process, and further has a valve at its wall portion for rotating the valve At this time, the intake valve and exhaust valve passing through the valve cover successively flow into and discharge from the combustion chamber.

The present invention aims to provide an internal combustion engine suitable for gardening machines, designed to be hand-held and manually operated by an operator.

According to the present invention, there is provided a rotary valve internal combustion engine comprising: a piston connected to a crankshaft and reciprocable in a cylinder, the cylinder having a combustion end; and a combustion chamber formed by the piston and the combustion end of the cylinder Constitutes a part of the combustion chamber; a valve cover, fixed outside one of the combustion ends of the cylinder, and constitutes a hole and a rotary valve, the rotary valve can rotate along a rotary valve shaft of the hole in the valve cover, the rotation The valve has a hollow valve body having an internal volume forming part of the combustion chamber, wherein the internal volume of the hollow valve body contains combustion gas throughout the combustion process, and further has a When the valve rotates, the intake valve and exhaust valve through the valve cover continuously flow into and discharge from the combustion chamber, the internal combustion engine has a carburetor for controlling the entry into the internal combustion engine An air/fuel mixture, and an exhaust muffler for one of the exhaust gases, wherein the valve arrangement arranges the exhaust muffler and the carburetor on opposite sides of the internal combustion engine, and the valve angle is set as the body of the carburetor The body of the muffler is substantially parallel to the centerline of the internal combustion engine.

The preferred embodiment of the present invention will be described below in conjunction with the drawings.

Now refer to FIG. 1, which is a single-cylinder air-cooled internal combustion engine. The internal combustion engine has a cylinder housing containing the cylinder 2. A piston 1 is connected to a crankshaft 3 in a conventional manner, and the crankshaft 3 is installed to rotate in a crankcase 14 to reciprocate in the cylinder 2. The upper part of the cylinder 2 is closed by one of the combustion chambers 4 in the combustion chamber housing. The combustion chamber housing has an intake valve 27 for allowing the intake air/fuel mixture to flow into the combustion chamber, and an exhaust valve 28 for exhaust gas to be discharged into and out of the combustion chamber 4, and controls the flow through a rotary valve 5. In this embodiment, the valve 5 is rotatable about an axis 5a in a valve cover 8 in the combustion chamber housing, the axis 5a being coaxial with the axis of the cylinder 2. In other embodiments, the axis of rotation of the valve body is offset from the axis 5a of the cylinder 2.

The rotary valve 5 has at its end remote from the combustion chamber 4 a concentric drive shaft 6 which carries a single ball bearing 7 that rotatably supports the valve 5 in a valve housing 8. The valve drive shaft 6 is fixed to a coaxial driven gear 9 which meshes with a drive gear 10 of a drive arrangement 11 whereby the driven gear 9 and rotary valve 5 are connected to the crankshaft 3. The drive arrangement 11 includes a drive shaft 12 that is located in a passage or tube 17 in the cylinder housing and is mounted on the upper bearing 18 adjacent to the drive gear 10 and the lower bearing 13 adjacent to the crankshaft 3 for rotation. The drive shaft 11 is provided with a bevel gear 15 which meshes with a corresponding bevel gear 16 fixed on the crankshaft so as to rotate together with the crankshaft 3. Therefore, the rotation of the crankshaft 3 and the movement of the piston and the rotation of the rotary valve 5 are coordinated, so that the internal combustion engine runs a typical four-stroke cycle. For this reason, the diameter of the driven gear 9 is twice the diameter of the drive gear 10, so that the rotary valve 5 rotates at half the engine speed. The rotary valve 5 includes a substantially cylindrical rotary valve body 5 which can rotate around a rotary valve axis 5a and slide tightly in the hole of the valve cover 8. The rotary valve 5 has a hollow valve body, which The hollow valve body has an internal volume 19 forming part of the combustion chamber. The valve has a substantially cylindrical body portion, which includes the valve body 19 itself, whose diameter is slightly larger than the shaft 6, which forms a shoulder portion 14 on which the rolling ring of the ball bearing 7 is disposed. The valve body 19 extends into the combustion chamber and has a volume 20 inside, which volume 20 forms part of the combustion chamber 4 and contains combustion gases in all stages of the combustion process.

The diameter of the shaft 6 portion of the rotary valve 5 is only slightly smaller than the valve body 19 to provide the shoulder 14. The shaft is solid to provide a good path for conducting heat from the valve body 19 to the outside.

The rotary valve body 19 has a valve 21 which enables the communication fluid to flow into and out of the internal volume of the valve and the combustion chamber successively through the intake valve and the exhaust valve in the valve cover during the rotation of the valve. In the present embodiment, the valve 21 is in the form of a groove formed in the lower peripheral edge 22 of the wall 23 of the valve body adjacent to the combustion chamber 4, the groove extending upward from the lower edge of the valve wall to form the valve one侧的阀21。 The side valve 21.

Ignition through a spark plug is fixed in a plug hole 25 which is formed in the valve cover 8 and extends toward the valve hole. In another embodiment, the internal combustion engine operates on the principle of compression ignition.

Please refer now to FIG. 2, which is a partial cross-sectional plan view of an internal combustion engine for hand-held and manually-operated gardening machines (such as hand-held long-handed weeders or hedge trimmers). In this type of machine, the exhaust gas and exhaust muffler need to be located away from the operator, and a carburetor for controlling the air/fuel mixture through the intake valve is located toward the operator. This is because the heat of the exhaust gas and the operator may need to adjust the carburetor. A carburetor and bellows assembly 29 is attached to the intake valve 27, and an exhaust muffler 30 is connected to the exhaust valve 28. Ideally, the carburetor bellows assembly 29 and the exhaust muffler 30 should be substantially parallel to the centerline of the crankshaft. This not only simplifies manufacturing, but also makes the appearance of the internal combustion engine concise, making it easier to install the internal combustion engine in a typical gardening machine. However, in order to provide the correct valve timing of the internal combustion engine (which is determined by the position of the intake valve and exhaust valve in the valve cover), it is necessary to tilt both the intake valve and the exhaust valve from their ideal angles. The radius extending quasi from the cylinder axis.

In addition, because any limitation of the non-radial valve angle on the intake valve fluid will have a greater impact on the power of the internal combustion engine than the equivalent limit of the exhaust valve, the valve angle is set so that the intake valve is closer to the ideal radial than the exhaust valve angle.

In this embodiment, the top dead center timing point is inclined 10° from the center line of the internal combustion engine toward the intake side, in other words, when the piston is at the top dead center, the center line of the valve is directed 10 degrees toward the internal combustion engine side closest to the operator. This allows the intake valve port in the valve housing to rotate 10 degrees toward the operator. This allows the intake valve 27 to be closer to the ideal radial angle than the exhaust valve. Next, the intake valve 27 is further inclined by 11° from the radial axis of the cylinder shaft so that the mounting flange of the carburetor bellows assembly 29 is substantially parallel to the centerline of the internal combustion engine.

The centerline of the exhaust valve 28 is offset from the radial axis by 15°. The exhaust muffler has an angled flange 33 which cooperates with the exhaust valve 28 so that the body of the exhaust muffler is substantially aligned with the centerline 31 of the internal combustion engine.

The exhaust silencer 13 has a two-piece housing structure of a silencer and a flange to cooperate with an angled exhaust valve. This has the advantage of avoiding the use of separate tubes or cartridges between the exhaust valve and the silencer body.

As shown in FIG. 2, the intake side of the cylinder has a curved plate 34 for guiding cooling air around the rear of the cylinder to provide cooling air flow around the rear of the cylinder.

As shown in FIG. 3, the sliding plate 35 at the rear of the internal combustion engine forms the lower surface of the cooling air flow passage, forcing the cooling air to be discharged from the rear of the fairing, instead of short-circuiting into the cooling air intake valve.

1: piston 17: Tube 2: cylinder 18: upper bearing 3: crankshaft 19: Valve body 4: combustion chamber 20: Volume 5: rotary valve 21: Valve 5a: axis 22: Next rim 6: drive shaft 23: Wall 7: Ball bearing 25: Plug hole 8: Valve cover 27: Intake valve 9: coaxial driven gear 28: Exhaust valve 10: Drive gear 29: Bellows components 11: Drive configuration 30: Exhaust silencer 12: Drive shaft 31: Centerline 13: Lower bearing 33: flange 14: crankcase 34: curved plate 15: bevel gear 35: Sliding plate 16: bevel gear

1 is a cross-sectional view of a single-cylinder air-cooled spark ignition rotary valve internal combustion engine. 2 is a partial cross-sectional plan view of an embodiment of an internal combustion engine used with hand-held and manually-operated gardening machines, such as hand-held long-handed weeders or hedge trimmers. 3 is a partial side view of the internal combustion engine shown in FIG. 2.

no

1: piston

2: cylinder

3: crankshaft

4: combustion chamber

5: rotary valve

5a: axis

6: drive shaft

7: Ball bearing

8: Valve cover

9: coaxial driven gear

10: Drive gear

11: Drive configuration

12: Drive shaft

13: Lower bearing

14: crankcase

15,16: bevel gear

17: Tube

Claims (8)

A rotary valve internal combustion engine includes: a piston connected to a crankshaft and reciprocating in a cylinder, the cylinder has a combustion end; a combustion chamber, the piston and the combustion end of the cylinder constitute a part of the combustion chamber; A valve cover is fixed outside one of the combustion ends of the cylinder, and constitutes a hole and a rotary valve, the rotary valve rotates along a rotary valve shaft of the hole in the valve cover, the rotary valve has a hollow valve body , The hollow valve body has an internal volume forming part of the combustion chamber, wherein the internal volume of the hollow valve body accommodates combustion gases throughout the combustion process, and further has a valve at a wall portion of the valve When rotating, the intake valve and exhaust valve through the valve cover cause fluid to flow into and out of the combustion chamber successively. The internal combustion engine has a carburetor for controlling the air/fuel mixture entering the internal combustion engine. And an exhaust muffler for one of the exhaust gases, wherein the valve angle is arranged such that the body of the exhaust muffler and the body of the carburetor are on opposite sides of the internal combustion engine and are substantially parallel to one of the internal combustion engines Centerline. The rotary valve internal combustion engine as described in item 1 of the patent application range, wherein, when the internal combustion engine is at the center of the top, the valve is tilted toward the operator by a predetermined degree, and the angular deviation reduces the radial deviation of the intake valve It is necessary to realize one of the mounting flanges of the carburetor, which is substantially parallel to the centerline of the internal combustion engine. The rotary valve internal combustion engine as described in item 1 of the patent application scope, wherein the center line of the intake valve is offset by a predetermined degree from a radial line of the cylinder shaft, and the angle deviation causes the carburetor The mounting flange of is substantially parallel to the centerline of the internal combustion engine. The rotary valve internal combustion engine as described in item 1, 2 or 3 of the patent application scope, wherein the center line of the exhaust valve is offset by a predetermined degree from a radial line of the cylinder shaft, and the angle deviation The main body of the exhaust muffler is substantially parallel to the centerline of the internal combustion engine. The rotary valve internal combustion engine according to any one of claims 1 to 3, wherein the radial offset of the intake valve is smaller than the radial offset of the exhaust valve. The rotary valve internal combustion engine according to any one of the aforementioned patent applications, wherein the exhaust muffler has an angled flange that cooperates with a corresponding exhaust valve to muffle the exhaust The main body of the engine is substantially aligned with the centerline of the internal combustion engine. The rotary valve internal combustion engine according to any one of the aforementioned patent applications, wherein an air guide plate guides cooling air around the rear of the cylinder toward the rear of the cylinder. A rotary valve internal combustion engine as described in any of the aforementioned patent applications, wherein a sliding plate at the rear of the internal combustion engine forces cooling air to be discharged from the rear of a fairing instead of short-circuiting into the cooling air intake valve.

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