JPS597536Y2 - Scavenging device for 2-stroke fuel injection engine - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a scavenging device for a two-stroke fuel injection engine that improves scavenging efficiency.

Generally, in a two-stroke fuel injection engine, one exhaust hole and a plurality of scavenging holes are arranged around the cylinder wall, and the outlet of the scavenging hole is twisted on the opposite side of the exhaust hole.

Especially when the load is low, scavenging air often collides with each other and blows through to the exhaust hole, and there is little fresh air near the spark plug at the top of the cylinder, causing irregular combustion.

This idea has been improved to avoid this problem.
Embodiments of the present invention shown in the drawings will be described below.

At the top of the cylinder 1 is a dome-shaped cylinder head 2.
are connected to each other, and the cylinder head 2 is provided with an ignition plug 3 and a fuel injection nozzle 4.

5 is a cooling water passage.

Accordingly, in the present invention, one exhaust hole 7 and three scavenging holes, ie, a first scavenging hole 8, a second scavenging hole JL9, and a third scavenging hole 10, are arranged at equal intervals around the inner wall 6 of the cylinder 1.

Each of the scavenging holes 8, 9, and 10 faces outward from the center of the cylinder 1, as shown by arrow A in FIG.
Arrange them by twisting them in the same direction.

Moreover, the upper edge of each scavenging hole 8, 9, 10 is such that the upper edge of the first scavenging hole 8 is in the B direction, the upper edge of the second scavenging hole 9 is in the C direction, and the upper edge of the third scavenging hole 10 is in the D direction. The blowing angles B, C, and D are arranged so as to face the upper, middle, and lower parts of the cylinder 1, respectively, as shown in FIG.

Further, the upper edge of the second scavenging hole 8 and the upper edge of the second scavenging hole 9 are shifted by E in the axial direction, and the upper edge of the second scavenging hole 9 and the upper edge of the third scavenging hole 1
Each scavenging hole 8 is offset from the upper edge of 0 by F in the axial direction.
, 9.10 are arranged with their upper edges shifted in the axial direction.

The effect will be explained.

When the piston descends, the exhaust hole 7 begins to open and exhaust begins.

Since the upper edges of the scavenging holes 8, 9, and 10 are shifted in the axial direction, the first scavenging hole 8, the second scavenging hole 9, and the third scavenging hole 1
0, they begin to open at different timings, and fresh air is blown in.

Since the scavenging holes 8, 9, and 10 are twisted and arranged so as to face outward from the center of the cylinder, a vortex flow of fresh air is created within the cylinder 1.

Further, since the upper edges of each scavenging hole 8, 9, and 10 are oriented upward, middle, and downward, fresh air enters the entire cylinder 1.

Since the top, middle, and bottom are opened in this order, fresh air is also sent to the vicinity of the ignition plug 3 at the top.

In this way, fresh air is sent to the upper part, creating a vortex flow that improves ignition performance.

Note that since the fresh air is in the form of a vortex, some of it blows directly into the exhaust hole 7, but since it is only air, no fuel is wasted.

As explained above, this idea opens one exhaust hole and three scavenging holes around the inner wall of the cylinder, and the three scavenging holes are twisted in the same direction so as to face outward from the center of the cylinder. In addition, the three scavenging holes have different blowout angles at the upper edges and are arranged with the upper edges shifted in the axial direction, so fresh air can be blown out at different timings to the upper, middle, and lower parts. This allows fresh air to be sent to the top.

Also, since the fresh air is turbulent and turbulent inside the cylinder, it has good ignitability.

In this way, irregular combustion, which occurs especially at low loads, can be prevented and smooth operation can be achieved.

Furthermore, by improving the ignitability, the effective use of fuel increases and fuel savings can be achieved.

[Brief explanation of the drawing]

The figures show one embodiment of the present invention, with Figure 1 being a cross-sectional view and Figure 2 being a cross-sectional view.
The figure is a vertical cross-sectional view taken along the line X-X in Figure 1, and Figure 3 is a longitudinal cross-sectional view taken along the line Y-Y in Figure 1.
FIG. 1...Cylinder, 6...Inner wall, 7...
...Exhaust hole, 8...First cleaning hole, 9...
...Second scavenging hole, 10...Third scavenging hole, B,
C, D...Blowout angle.

Claims (1)

[Scope of utility model registration request] One exhaust hole and three scavenging holes are opened around the inner wall of the cylinder, and the three scavenging holes are twisted in the same direction so as to face outward from the center of the cylinder. A scavenging device for a two-stroke fuel injection engine, characterized in that the blowing angles of the upper edges are changed and the upper edges are respectively shifted in the axial direction.