JPH0749766B2 - Engine intake / exhaust mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an intake / exhaust mechanism of an engine, in which mechanical resistance is reduced.

<Background Art> Generally, in an engine, a piston reciprocates in a cylinder to perform intake, compression, expansion, and exhaust operations.

A four-cycle engine that performs this series of cycles in four steps is equipped with an intake valve that opens during the intake stroke and an exhaust valve that opens during the exhaust stroke.The intake valve is opened during the intake stroke to suck the mixture from the intake passage into the cylinder. During the compression stroke, the air-fuel mixture is compressed, the air-fuel mixture compressed during the expansion stroke is explosively combusted, and the exhaust valve is opened during the exhaust stroke to blow the expanded gas from the cylinder into the exhaust passage. An engine having an intake valve and an exhaust valve repeats a series of cycles, and the intake valve and the exhaust valve constantly open and close in accordance with the operation of the piston.

In a typical four-cycle engine, the intake and exhaust valves of the cylinder constantly repeat opening and closing operations, so the opening and closing of the intake and exhaust valves causes energy loss and has a large mechanical resistance, especially in the high engine speed range. is there. For this reason, it is difficult to obtain a smooth engine speed increase, and a smoother engine speed increase has been demanded in recent years due to the demand for improved riding comfort.

<Objects of the Invention> The present invention has been made to meet the above-described demands, and an engine that has a single intake / exhaust port of a cylinder and a valve that performs opening / closing operations and has a small mechanical energy loss even in a high rotation range of the engine The purpose of the present invention is to provide an intake / exhaust mechanism to increase the intake / exhaust area of the cylinder to improve intake / exhaust efficiency, achieve a smoother engine speed increase, and further improve quietness of the engine. .

<Means for Achieving the Object> An engine intake / exhaust mechanism according to the present invention for achieving the above object is a shaft which communicates with a combustion chamber of an engine through a cylinder passage in a housing and rotates in synchronization with a crankshaft. Is rotatably supported on the housing, and a cylindrical rotor is provided concentrically with the shaft to close the cylinder passage with an outer peripheral surface and divide the inside of the housing into two housing chambers. An intake passage is opened in one of the housing chambers to form an intake chamber, and an exhaust passage is opened in the other housing chamber to form an exhaust chamber. The intake chamber and the cylinder passage are communicated with each other, and a groove width is set in the axial direction of the shaft. An intake side notch that gradually differs is provided on the outer peripheral surface of the rotor so that the exhaust chamber and the cylinder passage communicate with each other and the groove width gradually differs in the axial direction of the shaft. The air-side notch is provided on the outer peripheral surface of the rotor in a different phase from the intake-side notch, and the rotor is movable in the axial direction of the shaft within the housing.

<Operation> The rotor rotates together with the shaft in the housing in synchronization with the crankshaft, and the intake chamber and the cylinder passage communicate with each other through the cutout on the intake side during the intake stroke to move the rotor in the axial direction of the shaft. The groove width of the intake side notch opening in the cylinder passage is changed to change the intake timing. During the exhaust stroke, the exhaust chamber communicates with the cylinder passage through the exhaust side notch, and by moving the rotor in the axial direction of the shaft, the groove width of the exhaust side notch opening in the cylinder passage changes and the exhaust timing changes. . During the compression / expansion process, the outer peripheral surface of the rotor blocks the cylinder passage.

<Examples> FIG. 1 is a sectional side view of an intake / exhaust mechanism of an engine according to an embodiment of the present invention, and FIG. 2 is a view taken along the line II-II in FIG.
The drawing shows the III-III arrow in FIG. 1, the perspective view of the rotor in FIG. 4, and the operation stroke state in FIGS. 5 (a), (b), (c), and (d). There is.

Piston 2 which moves up and down by the rotation of crankshaft 1
A combustion chamber 4 is formed by the cylinder 3 and the cylinder 3, and a cylinder passage 5 is provided above the combustion chamber 4. A housing 6 is disposed above the combustion chamber 4, and the inside of the housing 6 communicates with the combustion chamber 4 via a cylinder passage 5. A shaft 7 is rotatably supported by the housing 6, and the shaft 7 is synchronously rotated so as to make one rotation when the crankshaft 1 makes two rotations. A cylindrical rotor 21 is concentrically provided on the shaft 7 in the housing 6, and is divided into an intake chamber 6a and an exhaust chamber 6b by the rotor 21 in the housing 6, and the cylinder passage 5 is an outer peripheral surface of the rotor 21. Is blocked by. The rotor 21 can be moved in the axial direction of the shaft 7 within the housing 6 by a drive mechanism (not shown). An intake passage 9 communicates with the intake chamber 6a, and an exhaust passage 10 communicates with the exhaust chamber 6b.

An intake side notch 22 is formed on the outer peripheral surface of the rotor 21 so as to connect the intake chamber 6a and the cylinder passage 5 to each other and extends in the direction of the rotation center axis of the rotor 21, and the groove H of the intake side notch 22 has a tapered shape with a gradually varying width. Has become. An exhaust side notch 22 communicating with the exhaust chamber 6b and the cylinder passage 5 and extending in the rotation center axis direction of the rotor 21 is formed on the outer peripheral surface of the rotor 21 whose phase is changed by 45 degrees on the rear side of the intake side notch 22 in the rotation direction of the rotor 21. 23 is formed, and the groove portion H of the exhaust side notch 23 has a taper shape in which the width is gradually different. The rotor 21 is attached to the shaft 7 in a state where the intake side notch 22 communicates with the intake chamber 6a and the cylinder passage 5 during the intake stroke.

By doing so, the shaft 7 makes one revolution when the crankshaft 1 makes two revolutions, so that the intake chamber 6a communicates with the cylinder passage 5 at the intake side notch 22 during the intake stroke,
The cylinder passage 5 is closed by the outer peripheral surface of the rotor 21 during the compression / expansion stroke, and the exhaust chamber 6b and the cylinder passage 5 communicate with each other through the exhaust side cutout 23 during the exhaust stroke.

The operation of the above configuration will be described with reference to FIG. The shaft 7 rotates in synchronization with the rotation of the crankshaft 1, and the rotation of the shaft 7 causes the rotor 21 to rotate within the housing 6. During the intake stroke, the intake chamber 6a communicates with the cylinder passage 5 through the intake-side cutout 22, and the air-fuel mixture sent from the intake passage 9 is sucked into the combustion chamber 4 through the intake-side cutout 22 from the intake chamber 6a. (See FIG. 5 (a)). During the compression stroke and the expansion stroke, the cylinder passage 5 is closed by the outer peripheral surface of the rotor 21, and the air-fuel mixture in the combustion chamber 4 is compressed and expanded (Fig. 5 (b),
(See (c)). Exhaust chamber 6b and cylinder passage 5 during the exhaust stroke
Are communicated with the exhaust side notch 23, and the gas expanded in the combustion chamber 4 is discharged from the exhaust passage 10 through the exhaust side notch 23 through the exhaust chamber 6b (see FIG. 5 (d)).

By moving the rotor 21 in the axial direction of the shaft 7, the width of the groove portion H of the intake side notch 22 and the exhaust side notch 23 communicating with the cylinder passage 5 can be changed during the intake stroke and the exhaust stroke. .

In the intake / exhaust mechanism described above, the intake / exhaust passage of the cylinder 3 need only be the cylinder passage 5, and since a valve for performing opening / closing operation during intake / exhaust is not required, the area of the cylinder passage 5 can be set large. In addition to being able to achieve a high compression ratio, it is possible to reduce mechanical energy loss in the high engine speed region.

Further, by moving the rotor 21 in the axial direction of the shaft 7, the width of the groove portion H of the intake side notch 22 and the exhaust side notch 23 communicating with the cylinder passage 5 can be changed during the intake stroke and the exhaust stroke. it can. Therefore, it is possible to adjust the intake and exhaust timings, and it is possible to obtain the optimum intake and exhaust timings according to the state of the vehicle. The groove shapes of the intake-side cutout 22 and the exhaust-side cutout 23 can be variously changed such that the taper directions are opposite to each other.

<Effects of the Invention> The engine intake / exhaust mechanism of the present invention has a single intake / exhaust port of the cylinder, eliminates a valve for opening / closing, and mechanically operates only the rotation of the rotor in a high engine speed range. Since the mechanical energy loss is reduced, the area of the intake / exhaust port of the cylinder can be increased to improve the intake / exhaust efficiency, a smoother engine speed increase can be achieved, and the quietness of the engine can be further improved. In addition, a notch with gradually varying groove width is provided on the outer peripheral surface of the rotor,
By making the rotor movable in the axial direction, it becomes possible to arbitrarily change the intake timing and the exhaust timing. Therefore, it is possible to obtain the optimum intake and exhaust timings according to the state of the vehicle.

[Brief description of drawings]

FIG. 1 is a sectional side view of an intake / exhaust mechanism of an engine according to an embodiment of the present invention, FIG. 2 is a view taken along the line II-II in FIG. 1, and FIG.
1 is a perspective view of the rotor in FIG. 1, FIG. 4 is a perspective view of the rotor, and FIGS. 5 (a), (b), (c), and (d) are operation stroke diagrams thereof. In the figure, 1 is a crankshaft, 2 is a piston, 3 is a cylinder,
4 is a combustion chamber, 5 is a cylinder passage, 6 is a housing, 6a is an intake chamber, 6b is an exhaust chamber, 7 is a shaft, 9 is an intake passage, 10
Is an exhaust passage, 21 is a rotor, 22 is an intake side notch, and 23 is an exhaust side notch.

Claims (1)

[Claims] 1. A housing is connected to a combustion chamber of an engine through a cylinder passage, and a shaft that rotates in synchronization with a crankshaft is rotatably supported by the housing. The outer peripheral surface closes the cylinder passage and the shaft is closed. A cylindrical rotor that divides the inside of the housing into two housing chambers is provided concentrically with the shaft, and an intake passage is opened in one of the housing chambers divided by the rotor to form an intake chamber, and at the other housing chamber. The exhaust passage is opened to form an exhaust chamber, the intake chamber and the cylinder passage are communicated with each other, and an intake side notch having a groove width gradually different in the axial direction of the shaft is provided on the outer peripheral surface of the rotor. An exhaust side notch having a groove width gradually different in the axial direction of the shaft communicating with the passage is provided on the outer peripheral surface of the rotor in a different phase from the intake side notch. Intake and exhaust mechanism of an engine to be movable in the axial direction of the shaft with the rotor in the housing.