JPS6332971B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an irregular combustion prevention device for a two-stroke engine, and in particular, to a device for preventing irregular combustion of a two-cycle engine, and in particular to a device for preventing a throttle valve by utilizing the movement of a governor weight provided on a shaft that interlocks with an axle. The present invention relates to an irregular combustion prevention device for a two-stroke engine having a vehicle speed control device that controls the opening degree.

[Conventional technology]

Conventionally, speed control devices for vehicles, such as golf cars, used to keep the vehicle speed constant have a governor weight installed on a shaft linked to the axle, and a governor weight that adjusts the speed of the shaft according to the rotational speed of the axle. The speed limiter lever is comprised of a lifter that is moved in the direction, a governor fork that is axially interlocked with the lifter, and a speed limiter lever that is connected at one end to the governor fork and at the other end to the adjustment lever of the throttle valve. The vehicle speed control device is configured such that when an accelerator pedal is depressed and the vehicle speed increases, the lifter is moved by a governor weight;
The amount of movement of this lifter is transmitted to the throttle valve adjustment lever via the governor fork and speed limiter lever, and when the accelerator pedal is depressed, the throttle valve is adjusted to a low opening so that the vehicle speed does not exceed a certain speed. Control as follows.

[Problem that the invention seeks to solve]

However, in the conventional vehicle speed control device, the speed control function works even when the vehicle is traveling downhill, and although the throttle valve is adjusted to a low opening degree, the inertia of the vehicle causes the vehicle to Speed increases. As a result, only the engine speed increases while the throttle valve is at a low opening. Therefore, in a two-stroke engine that exhausts exhaust gas from the combustion chamber by guiding the intake air-fuel mixture into the cylinder, the throttle valve opens at a low opening, so not enough air-fuel mixture is supplied, and the exhaust gas is not fully exhausted. It will not be done. As a result, two-stroke engines repeatedly ignite while the exhaust gas remains in the combustion chamber, which makes it difficult to burn, resulting in irregular combustion and irregular engine noise, especially at high engine speeds. It was a problem going downhill.

SUMMARY OF THE INVENTION An object of the present invention is to provide an asymmetric combustion prevention device for a two-stroke engine that does not cause asymmetric combustion even when the vehicle is running downhill due to inertia in a vehicle equipped with a speed control device.

[Means for solving problems]

In order to achieve the above object, the irregular combustion prevention device for a two-cycle engine of the present invention connects a throttle valve disposed in an intake passage and an exhaust valve disposed in an exhaust passage with a link mechanism, and
The vehicle is provided with a speed control device that simultaneously controls both valves to a low opening when the vehicle runs due to inertia and the speed of the vehicle exceeds a magnitude defined by the opening of the throttle valve. .

[Effect]

According to the above configuration, when the vehicle runs downhill, the engine speed increases due to inertia, but the throttle valve opens to a low degree due to the action of the speed control device, and at the same time, the link mechanism causes the exhaust to be exhausted. The valve also opens at a low degree. For this reason, the low pressure rises and the pressure inside the combustion chamber also rises, so the temperature inside the combustion chamber rises. As a result, the air-fuel mixture sucked into the combustion chamber can be reliably ignited, and asymmetric explosion due to asymmetric combustion can be prevented.

Furthermore, when the vehicle travels on a flat surface, the opening degree of the throttle valve is controlled by the speed control device, so that the speed of the vehicle can be maintained constant.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Figures 1 and 2 show two-cycle engine 1.
FIG. 1 is a side view and a plan view of a golf car equipped with an engine 0, each with a part of the body frame cut away to show the schematic structure around the engine. In the figure,
A carburetor 12 is arranged adjacent to the engine 10, and an exhaust pipe 14 is arranged on the side of the engine 10 opposite to the carburetor 12 side. A throttle valve (not shown in FIGS. 1 and 2) is provided inside the carburetor 12, and an exhaust pipe 1
An exhaust valve (not shown in FIGS. 1 and 2) is provided on the inlet side of the engine 4, that is, on the side that contacts the engine 10. The throttle valve and the exhaust valve are interlocked so as to synchronize their opening and closing operations via a link mechanism 16, which will be described later. The rotational force obtained from the engine 10 is transmitted to the secondary rotating shaft 2 through the primary rotating shaft 18.
The secondary rotating shaft 20 is provided with a vehicle speed control device to be described later. In FIG. 2, a speed limiter lever 22 constituting this vehicle speed control device is shown.
This speed limiter lever 22 is interlocked with a throttle valve in the kibrator 12 via a part of the link mechanism 16.

FIG. 3 is a plan view showing the relationship between the engine 10 and the link mechanism 16, and a schematic diagram of the speed control device 24 is also shown in FIG. Also, Fig. 4 is a sectional view taken along the - line in Fig. 3, and Fig. 5 is a sectional view along the - line in Fig. 3.
FIG. 6 is a side view taken along the line - in the figure, and FIG. 6 is a sectional view taken along the line - in FIG.

The structure of the vehicle speed control device 24 shown in FIG. 3 will be explained. As shown in the figure, an accelerator pedal 26 of the golf car is swingably supported by a shaft 28 and a control wire 30.
One end of is connected. The control wire 30 is guided through a guide tube 32 and has a torsion spring 3 at the other end protruding from the guide tube 32.
It is connected to the tip of 4.

The torsion spring 34 is wound around the governor shaft 36, and the rising pieces 38 and 40 from the speed limiter lever 22, which is integrally attached to the governor shaft 36, is urged clockwise in FIG. is in contact with. An adjusting screw 42 is attached to the rising piece 40, and the repulsive force of the torsion spring 34 is adjusted by moving this screw forward and backward. A governor fork 46 is pivotally supported at the protruding tip of the governor shaft 36 by a screw 44.

This governor oak 46 is the governor shaft 36
The tip of the lifter 48 is attached to the secondary rotating shaft 20 so as to be able to slide freely in the axial and rotational directions. governor weight 50
When the lifter 4 rotates outwardly due to centrifugal force about its support shaft 52, the resulting lifter 4
The movement of 8 (towards the right in Figure 3) is governor shaft 3.
6, the signal is transmitted to a throttle lever, which will be described later.

One end of a rod 54 forming a part of the link mechanism 16 is pivotally supported at the tip of the speed limiter lever 22, and a throttle lever 57 to which a throttle shaft 56 is attached is pivotally supported at the other end of the rod 54. supported. Furthermore, as shown in FIG. 4, a throttle valve 58 is fixed to the throttle shaft 56 by screws 59, 59, so that the amount of air-fuel mixture passing through an intake passage 60 in the carburetor 12 can be adjusted. . The member indicated by the reference numeral 61 in FIG. 4 is a return spring that biases the throttle valve in the closing direction.

Next, the link mechanism 16 will be explained with reference to FIG. One end of a rod 62 is pivotally supported at a position near the pivot point of a rod 54 at the tip of the speed limiter lever 22, and the other end of the rod 62 is connected to an arm 66 bent into a crank shape via a ball joint 64. connected. That is, as shown in FIG. 5, the bent upper end 68 of the arm 66 is connected to the pin 63 and the ball joint 64.
It is rotatably connected to the rod 62 via. In addition, the bent lower end 7 of the arm 66
0 is rotatably connected to a rod 76 connected to the lower end of the exhaust valve shaft 74 via a pin 71 and a ball joint 72. Further, the arm 66 has a central portion sandwiched between an upper end 68 and a lower end 70, which is rotatably supported within holders 78, 78 attached to the fan case. Therefore, when the speed limiter lever 22 rotates counterclockwise in FIG. 3, the rod 62 moves in the direction of arrow _A1.
The rod 76 rotates in the direction of arrow _A2 , ie, in the opening direction of the exhaust valve shaft 74. Also,
When the speed limiter lever 22 is rotated clockwise in FIG. 3, the rod 62 moves in the direction of arrow _B1 and the rod 76 rotates in the direction of arrow _B2, ie, in the closing direction of the exhaust valve shaft 74. In addition, Rod 76
A spring 82 is disposed between the exhaust pipe 14 and the exhaust pipe 14, and urges the rod 76 to rotate in the direction of arrow _B2 , that is, the exhaust valve shaft 74 in the closing direction.

As shown in FIGS. 4 and 6, the exhaust valve shaft 74 has bolts 86A and 86A.
It is fixed by. The exhaust valve 84 connects the combustion chamber 86 of the engine 10 to the exhaust passage 8 of the exhaust pipe 14.
8. Adjust the amount of exhaust gas discharged. Note that after forming the convex portion 90 in the center of the exhaust valve 84, the section modulus of the exhaust valve 84 is increased to strengthen the rigidity and prepare for high-pressure exhaust gas. Note that the convex portion 90 is arranged toward the engine 10 side.

A lever 94 bent into a U-shape and having a groove 92 is fixed to the lower end of the exhaust valve shaft 74, as shown in FIG. 98 is fixed by caulking or the like. In this way,
The exhaust valve shaft 74 is connected to the rod 76, and the reason why the U-shaped lever 94 is interposed here is because extremely high temperature exhaust gas flows in the exhaust passage 88. From the exhaust gas through the shaft 74 to the ball joint 9
6. This is to reduce the thermal energy transferred to the rod 76 and to allow the ball joint 96 to operate normally. That is, by making the lever 94 U-shaped, the distance of the heat transfer path is lengthened, so that more heat energy is lost along the way, and the grease etc. on the ball joint 96 is prevented from burning out. It is.

Further, as shown by the chain line in FIG. 3, the rotation stroke of the exhaust valve 84 is at positions P, Q, and R.
The exhaust valve 84 is in a low opening state between positions P and Q, and is fully open at position R. The exhaust valve 84 can be widened by setting a low opening state between positions P and Q, and the pressure within the combustion chamber 86 can be sufficiently increased.

Note that the opening 100 shown in FIG. 4 is a scavenging hole that communicates with a crank chamber (not shown) and injects air-fuel mixture into the combustion chamber 86.

The embodiment of the present invention constructed as described above operates as follows.

First, when the accelerator pedal 26 is depressed, this is transmitted to the control wire 30 and the torsion spring 34 is wound counterclockwise in FIG. 3. With this, the speed limiter lever 2
2 is also swung counterclockwise together with the governor shaft 36, and the throttle lever 57, which is connected to this lever 22 via the rod 54, is rotated in the opening direction of the throttle valve 58. At the same time, Rod 6
2 moves the rod 76 in the direction of arrow _A1 and the rod 76 in the direction of arrow _A2 to rotate the switching valve shaft 74 in the opening direction.

When the vehicle speed increases, the governor weight 50 attached to the secondary rotating shaft 20 rotates counterclockwise in FIG. 3 about the shaft 52 due to centrifugal force.
Move the lifter 48 to the right. The movement of the lifter 48 causes the governor fork 46 to rotate clockwise, causing the limiter lever 22 to rotate clockwise against the biasing force of the torsion spring 34. When the limiter lever 22 rotates clockwise, the rod 54 moves upward in FIG. 3 so that the throttle valve 58 is opened to a low degree with the accelerator pedal depressed. At the same time, limiter lever 22
The third rod 62, one end of which is
Move up in the arrow _B1 direction on the diagram. This rod 62
The movement of the ball joint 64, arm 66,
The pressure is transmitted to the rod 76 via the ball joint 72, and the rod 76 rotates in the direction of arrow _B2 in FIG. 3, that is, so that the exhaust valve 84 is opened to a low degree. Now, even when the vehicle is traveling downhill, as the vehicle speed increases, the throttle valve 58 opens to a lower degree.
Although a small amount of the air-fuel mixture is supplied into the combustion chamber 86, the vehicle speed is accelerated without being decelerated due to the inertial force of the vehicle. However, the throttle valve 5
8 becomes a low opening, the exhaust valve 84 is synchronously opened.
Since the opening degree also becomes low, the pressure inside the combustion chamber 86 increases as well as the exhaust pressure increases. As a result, the combustion chamber 8
The temperature inside the combustion chamber 86 increases, explosion occurs more reliably within the combustion chamber 86, irregular combustion can be prevented, and irregular engine noise does not occur.

[Effects of the Invention] As explained above, according to the present invention, when the engine is driven by the inertial force of the vehicle and the engine rotational speed increases while the vehicle is traveling downhill,
By simultaneously controlling the throttle valve and the exhaust valve to a low opening degree, the temperature inside the combustion chamber can be increased, so that irregular combustion can be completely prevented from occurring.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the internal structure of a golf car to which an embodiment of the present invention is applied, with a part of the body frame cut away; FIG. 2 is a plan view of the golf car shown in FIG. 1; 3 is a plan view of an embodiment according to the present invention, FIG. 4 is a sectional view taken along the line - in FIG. 3, and FIG. 5 is a side view taken along the line - in FIG.
FIG. 6 is a sectional view taken along the - line in FIG. 3. DESCRIPTION OF SYMBOLS 10... Two-stroke engine, 12... Carburetor, 14... Exhaust pipe, 16... Link mechanism, 20... Secondary rotating shaft, 24... Vehicle speed control device, 58... Throttle valve, 60... Intake passage, 84...exhaust valve, 88...exhaust passage.

Claims (1)

[Claims] 1 A throttle valve disposed in an intake passage and an exhaust valve disposed in an exhaust passage are connected by a link mechanism, and a vehicle is driven by inertia force, and the speed of the vehicle is determined by the opening degree of the throttle valve. A system for preventing irregular combustion for a two-stroke engine, comprising a speed control device that simultaneously controls both valves to a low opening degree when a prescribed magnitude is exceeded.