JPS6113101B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an operation shutdown device for an active thermal, ambient air combustion two-stroke internal combustion engine.

As a two-stroke internal combustion engine that can significantly reduce fuel consumption and harmful components in exhaust gas and achieve quiet operation, the cross-sectional area of the scavenging passage that connects the engine crank chamber and combustion chamber has been changed to the side closer to the crank chamber. Activated thermal atmosphere combustion 2 in which fresh air is allowed to flow into the combustion chamber at a low speed by narrowing the
A cycle internal combustion engine has already been proposed by the inventor. In this two-stroke internal combustion engine, an active thermal atmosphere is created in the combustion chamber by allowing fresh air to flow into the combustion chamber at a low speed, and this atmospheric condition is then maintained continuously during the compression stroke, so that at the end of the compression stroke, fresh air is introduced into the combustion chamber. is caused to ignite and burn without using a spark plug. As described above, in this internal combustion engine, combustion occurs without using the ignition plug, so even if the spark discharge of the ignition plug is stopped in order to stop the engine, the engine cannot be stopped.

The object of the present invention is to provide an engine stop device suitable for such an active thermal atmosphere combustion two-stroke internal combustion engine.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 and 2, 1 is a crankcase, 2 is a cylinder block fixed on the crankcase 1, 3 is a cylinder head fixed on the cylinder block 2, and 4 is a substantially flat top. A piston having a surface and capable of reciprocating within a cylinder liner 5 fitted in the cylinder block 2; 6 a combustion chamber formed between the cylinder head 3 and the piston 4; 7 disposed at the apex of the combustion chamber 6; spark plug,
8 is a crank chamber formed in the crankcase 1, 9 is a balance weight, 10 is a connecting rod, 11
12 is an intake passage formed in the cylinder liner 5; 13 is a carburetor; 14 is a carburetor throttle valve; 15 is a pair of scavenging holes formed in the cylinder liner 5; 16 is a pair of scavenging holes formed in the cylinder liner 5. 17 is an exhaust pipe, and 18 is an exhaust passage. The embodiment shown in FIGS. 1 and 2 is a two-stroke internal combustion engine of the simulator type, and its effective compression ratio is 6.5.

As shown in FIGS. 2, 5, and 6, the crankcase 1 has three crankcase parts 1a,
Consists of 1b and 1c. cylinder block 2
A pair of scavenging passages 19 are formed inside the combustion chamber 6 at the scavenging holes 15 and extend vertically along the outer wall of the cylinder liner 5. The scavenging passages 19 are formed at the upper end of the crankcase 1. and is connected to a pair of scavenging passages 20 that are aligned with the scavenging passage 19 . Hereinafter, the scavenging passages 19 and 20 will be collectively referred to as a second scavenging passage.

FIG. 3 shows the inner wall surface of the crankcase portion 1c, and FIG. 4 shows the inner wall surface of the crankcase portion 1a. Referring to FIGS. 3 and 4, grooves 21a and 21b are formed on the inner wall surfaces of the crankcase portions 1a and 1c, and extend along the circular periphery thereof, and the insides of these grooves 21a and 21b have a width L. A shallow annular groove 22 is formed. Also, this annular groove 22
A groove 23 extending along the annular groove 22 is formed on the bottom surface of the annular groove 22 . The grooves 21a, 21b are connected to each other at their lower ends 24, and one end 25 of the groove 23 connects the lower ends of the grooves 21a and 21b via a hole 26 drilled in each crankcase part 1a, 1c. 24. On the other hand, the other end 27 of the groove 23 is connected to a short vertical groove 28 extending downward. As shown in FIG. 2, a circular plate 29 is fitted into the annular groove 22, and this annular plate 29 includes the crankcase parts 1a, 1b,
1c are stacked on top of each other, the crankcase portions 1b cause the crankcase portions 1a, 1 to overlap, respectively.
pressed onto c. Accordingly, from FIGS. 2, 3, and 4, the crankcase parts 1a, 1b,
1c are stacked on top of each other to form the crankcase 1.
When forming each groove 21a, 21b, 23, 28
can be seen to form a passage. Furthermore, it can be seen from FIGS. 2 and 6 that the grooves 21a and 21b are deeper than the groove 23. Each crankcase part 1a, 1
A groove 3 having approximately the same depth as the grooves 21a and 21b and forming the scavenging passage 20 is provided at the upper end of the inner wall surface of the groove c.
0 is formed, and each groove 2 is formed at both ends of the bottom of this groove 30.
1a and 21b are opened. As shown in FIGS. 1 and 2, a horizontal hole 31 is formed in the lower end of the crankcase portion 1b and is aligned with each vertical groove 28 formed in each crankcase portion 1a, 1c. The hole 31 is connected to the inside of the crank chamber 8 via a vertical hole 32 bored on the bottom wall surface of the crank chamber 8 . In this way, each scavenging passage 20 has a groove 21.
a, 21b, hole 26, grooves 23, 28, horizontal hole 31,
It will be connected to the inside of the crank chamber 8 via the vertical hole 32. Below, grooves 21a, 21b, hole 26,
The grooves 23, 28, the horizontal hole 31, and the vertical hole 32 are collectively referred to as a first scavenging passage. Therefore, the crank chamber 8 is connected to the inside of the combustion chamber 6 via this first scavenging passage and the aforementioned second scavenging passage. When the engine is running, the intake hole 11
The fresh air introduced into the crank chamber 8 is compressed as the piston 4 descends, and then enters the vertical hole 32.
It is pushed into the horizontal hole 31 through. This fresh air then passes through the vertical groove 28, the groove 23, and the hole 26 to the groove 21.
a, 21b. As can be seen from FIGS. 1 and 6, the cross-sectional area of the groove 23 is extremely small, so fresh air flows at a high speed inside the groove 23, and then flows through the groove 23.
a, 21b. In this way, the fresh air is given flow energy within the groove 23, so that the vaporization of the liquid fuel is promoted during this time. Next, fresh air is sent into the grooves 21a and 21b, but the cross-sectional area of the grooves 21a and 21b is larger than the cross-sectional area of the groove 23, and the fresh air flows through the two grooves 21a and 21b.
The flow rate decreases because the water is divided into parts. However, the flow rate of the fresh air flowing in the grooves 21a, 21b is fast, and the liquid fuel that could not be vaporized in the grooves 23 is sufficiently vaporized in the grooves 21a, 21b.
After the vaporization of the liquid fuel is sufficiently promoted in this way, the fresh air in the first scavenging passage is sent into the second scavenging passage. At this time, the fresh air sent out from each groove 21a, 21b collides with each other in the scavenging passage 21, and the cross-sectional area of the groove 21a, 21b is larger than the scavenging passage 21.
Since the cross-sectional area of 0 is much larger, each groove 21
The fresh air sent out from a-21b is rapidly decelerated. This fresh air then passes through the scavenging passage 20,1.
9 at a low speed, the piston 4 reaches the scavenging hole 15.
When it is opened, it flows into the combustion chamber 6 at a low speed. When the piston 4 opens the scavenging hole 15 and fresh air flows into the combustion chamber 6, the groove 23 is throttled due to its small cross-sectional area even if the pressure inside the crank chamber 8 is considerably higher than the pressure inside the combustion chamber 6. Due to this throttling effect, fresh air cannot be rapidly blown into the combustion chamber 6, and as a result, the inflow speed of the fresh air is low throughout the inflow period. Since the fresh air flows into the combustion chamber 6 at a low speed in this way, there is almost no flow of residual burnt gas within the combustion chamber 6, thus preventing the heat dissipation of the residual burnt gas, thereby preventing the residual burnt gas from dissipating. The residual burnt gas is kept at a high temperature. Particularly at the beginning of compression during partial load operation, a large amount of residual burnt gas is present in the combustion chamber 6. Since the residual burnt gas in the combustion chamber 6 is large and high temperature, the combustion chamber 6
The fresh air sent into the combustion chamber 6 is heated and generates radicals, and as a result, an active heat atmosphere (an atmosphere in which radicals are generated is referred to as an active heat atmosphere) is formed within the combustion chamber 6. During the compression stroke, the gas flow in the combustion chamber 6 is very small, so there is little turbulence and loss of thermal energy to the combustion chamber wall, so the gas in the combustion chamber 6 becomes hotter as compression progresses, resulting in fresh air. generates more radicals. When radicals are being generated in this way, combustion called a pre-flame reaction has already started, and when the gas temperature in the combustion chamber 6 increases at the end of the compression stroke, a hot flame is generated and the ignition plug 7 is not activated. Self-ignites. Then, controlled gentle combustion is performed using the residual burnt gas, and when the piston 4 descends to open the exhaust hole 16, the burnt gas in the combustion chamber 6 is discharged into the exhaust passage 18.

In this way, in active thermal atmosphere combustion, self-ignition occurs without using the spark plug 7 during normal operation, so the spark plug 7
The engine cannot be stopped even if the spark discharge is stopped.

Referring to FIG. 1, a choke valve 40 is provided in the intake passage 12 upstream of the carburetor throttle valve 14, and the choke valve 40 is fixed on a rotatable choke shaft 42 by a lever 41. As shown in FIG. This choke valve 40 is used to throttle the intake passage 12 when starting the engine, but in the present invention it can also completely close the intake passage 12 as shown by the broken line. If the intake passage 12 is completely closed, fresh air will no longer be supplied into the combustion chamber 6, and the engine will stop operating.

FIG. 7 shows another embodiment. Referring to FIG. 7, a horizontal hole 31 is formed on the lower surface of the crankcase portion 1b.
A recess 43 is formed extending beyond the recess 4
A fixed hollow sleeve 44 is fitted into the interior of the housing 3 from below. A horizontal hole 3 is provided on the upper end side wall of this sleeve 44.
A pair of openings 45, 46 are formed which are aligned with 1. Further, a rotary valve 47 that can be rotated in a sealed manner is inserted into the sleeve 44, and this rotary valve 47
is a shaft 48 extending downwardly through the sleeve 44;
It is rotated by a lever 49 attached to.
The rotary valve 47 has openings 50, 51 that are alignable with the openings 45, 46, respectively, and normally rests in a position where the openings 50, 51 are aligned with the openings 45, 46, as shown in FIG. When the rotary valve 47 is rotated, the openings 45 and 46 are closed by the rotary valve 47, and as a result, fresh air is no longer supplied into the combustion chamber 6, so the engine stops.

FIG. 8 shows yet another embodiment. Referring to FIG. 8, an exhaust control valve 52 is provided within the exhaust passage 18 within the exhaust pipe 17. The exhaust control valve 52 is fixed on a valve shaft 54 which is rotated by a lever 53, and a cam 55 is fixed to the end of the valve shaft 54. Further, a stopper device 58 having a stopper 57 that is constantly pressed upward by a compression spring 56 is attached to the exhaust pipe 17, and the stopper 57 is arranged so as to be able to engage with the cam 55. The exhaust control valve 52 is always biased clockwise by a spring (not shown), and as shown in FIG. 8, when the stopper 57 and the cam 55 are engaged, the exhaust control valve 52 is slightly opened. . Preferably, the exhaust control valve 52 is configured in conjunction with the carburetor throttle valve so that as the carburetor throttle valve opens, the exhaust control valve 52 also gradually opens. By doing so, during partial load operation, the rapid ejection of exhaust gas from the exhaust hole 16 and the interference of exhaust pulsation are prevented by the throttling action of the exhaust control valve 52, thereby achieving more stable combustion in an activated heat atmosphere. is ensured. As mentioned above, the exhaust control valve 52 is energized clockwise, so when the stopper 57 is pulled down, the exhaust control valve 52 rotates clockwise to completely close the exhaust passage 18 and stop the engine operation. be done.
At this time, the stopper 57 is held at the retracted position where it contacts the lower edge of the cam 55 until the engine is started again and the exhaust control valve 52 is opened.

As described above, according to the present invention, the scavenging passage is constituted by the first scavenging passage having a long passage length and a small cross-sectional area, and the second scavenging passage having a short passage length and a large cross-sectional area. The gas is allowed to flow in the scavenging passage at high speed for a long period of time. As a result, the first
The vaporization of the liquid fuel in the fresh air is sufficiently promoted in the scavenging passage, the sufficiently vaporized fresh air is decelerated in the second scavenging passage, and then this fresh air is supplied into the combustion chamber at a low speed. It is possible to perform good activated thermal atmosphere combustion. Furthermore, since this activated thermal atmosphere combustion is not performed by the ignition action of the ignition plug, the engine cannot be stopped even if the ignition plug stops operating.
Operation of the engine can be stopped by providing a flow passage closing device in a working gas flow passage such as a scavenging passage or an exhaust passage.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of a two-stroke internal combustion engine according to the present invention, Fig. 2 is a side sectional view of Fig. 1, Fig. 3 is a view showing the inner wall surface of the crankcase portion 1c, and Fig. 4 is the crankcase portion. FIG. 5 is a plan view of the crankcase, FIG. 6 is a bottom view of the crankcase, FIG. 7 is a side sectional view of another embodiment, and FIG. 8 is still another embodiment. FIG. 11...Intake hole, 12...Intake passage, 15...
Scavenging hole, 16...Exhaust hole, 18...Exhaust passage, 1
9, 20...Exhaust passage, 40...Chiyoke valve, 4
7...Rotary valve, 52...Exhaust control valve.

Claims (1)

[Claims] 1. A first scavenging passage with a long passage length and a small cross-sectional area, which is connected to the engine crank chamber, and which is connected to the first scavenging passage and which is connected to the first scavenging passage and is connected to the first scavenging passage. The second scavenging passage has a short passage length and a large cross-sectional area, and the second scavenging passage is connected to a scavenging hole opening into the combustion chamber. A flow path closing device capable of completely closing the working gas flow path is provided in the working gas flow path leading to the working gas flow path, and the operation of the engine is stopped by completely closing the working gas flow path with the flow path closing device. This is an operation stop device for a 2-stroke internal combustion engine that burns in an active hot atmosphere.