JPS6115241Y2 - - Google Patents

Description

[Detailed explanation of the invention] In the mixer that mixes LPG and air when supplying LPG to the engine, the upstream and downstream sides of the throttle valve in the intake path are connected by an idle bypass. A valve body with an adjustment screw for idle adjustment is inserted into the bypass to obtain a predetermined idle rotation speed, but the tar contained in LPG is mainly squeezed out by the valve body and the seat. It adheres to the valve body and accumulates on the downstream side of the valve body, gradually reducing the effective area of the passage, making it impossible to secure the flow rate necessary for idling operation, resulting in a decrease in idling rotational speed.

That is, as shown in FIG.
In a structure in which the effective area of the passage is adjusted in cooperation with the truncated cone-shaped valve body 4, tar is first attached to the tip of the valve body 4, and this tar is gradually deposited and forms a barrier between the seat portion 3 and the valve body. The appendages extend to the area narrowed by the body 4 and grow in a state shown by reference numeral 5, thereby reducing the effective area of the passage. For this reason, the fifth
As shown in the figure, an improved version has been proposed in which the valve body 6 is formed into a cylindrical shape, and the effective area of the passage is adjusted by cooperating with the seat part 9 around the bypass 8 that opens into the valve chamber 7. However, in the same way, tar first adheres to the tip of the valve body 6, and this tar gradually accumulates to the area narrowed by the valve body 6 and the seat portion 9, and the deposits are as shown by the reference numeral 10. This will reduce the effective area of the passage. In these,
Tar tends to adhere in large quantities in passages where a mixture of LPG and air flows than in passages where only LPG flows, and this is caused by impurities contained in LPG being adsorbed to solid substances such as fine dust contained in the air. It is thought that the deposits produced by using only LPG are relatively soft and can be easily wiped off, whereas the deposits produced by the mixture are carbon-like and hard.

This proposal provides an LPG mixer that prevents tar from accumulating in a device that adjusts the effective passage area of the bypass, and is an idling bypass that connects the upstream and downstream sides of the throttle valve in the intake passage. A valve chamber is provided in the middle of the passage, a thin annular seat is provided at the opening end of the passage on the valve chamber inlet side, and the valve body is provided with a thin cylindrical portion with an open end surface. An adjusting screw is provided by inserting a valve body into the valve chamber orthogonal to the seat portion, and the outer circumferential surface of the valve body is configured to close a part of the seat portion. .

Next, an embodiment of the present invention will be described based on the drawings.

In FIG. 1, LPG vaporized under reduced pressure by a vaporizer (not shown) enters an annular chamber 14 surrounding a bench lily 13 through a supply passage 12 having an adjustable control valve 11, and enters the narrowest part of the bench lily 13 through a nozzle 15. sent towards. The upstream and downstream sides of the throttle valve 17 in the intake passage 16 are the idle passage 1.
8. Connected by bypass, the passage 18 has a valve chamber 19 in the middle, and this valve chamber 19 is connected to the idle port 2.
Connected to 0. A valve body 21 is inserted into the valve chamber 19 and can be adjusted from the outside with an integrated adjustment screw 22.

As shown in FIG. 2, the valve body 21 has a thin cylindrical portion 23 of uniform thickness with an open end, and a hollow portion 24 thereof is formed to an appropriate depth. Alternatively, as shown in FIG. 3, the tip may be formed into a thin-walled cylindrical portion 23 as a whole with a knife-edge-like tip and a gradually thickening wall toward the base end. A thin annular seat portion 25 is provided at the opening end of the passage 18 to the valve chamber 19, which is orthogonal to the valve body 21 and connected to the side surface of the valve chamber 19. By blocking, the effective area of the passage is adjusted.

According to the present invention configured as described above, the air flowing through the bypass increases the flow velocity due to the orifice effect of the thin-walled annular seat part, and when flowing into the valve chamber, the air flows through the valve body that partially blocks the seat part. Since the direction of the flow changes due to this, a vortex is generated in front and behind the flow, which makes it difficult for tar to adhere to the seat portion and the valve body disposed substantially in contact with the downstream side thereof. In addition, the tip surface of the valve body is formed into a thin-walled cylindrical shape, and as shown in Figures 4 and 5, there is virtually no tip surface where the largest amount of tar adheres and accumulates, and air flows at high speed. Coupled with flow, the adhesion of tar is almost completely prevented, and even if it does adhere, the phenomenon of accumulation and growth is extremely slow. Therefore, the need to readjust the effective area of the passage by operating the adjusting screw is significantly reduced compared to the conventional method, and a stable flow rate is guaranteed over a long period of time. Further, the effective area of the passage can be adjusted by the thin cylindrical portion without any change from conventional methods.

[Brief explanation of the drawing]

Figure 1 is a vertical sectional view showing an embodiment of the present invention, Figure 2
3 are enlarged vertical cross-sectional views showing different embodiments of the main parts, and FIGS. 4 and 5 are vertical cross-sectional views of conventional products. 13... Bench lily, 16... Intake path, 18...
...Passage, 19...Valve chamber, 21...Valve body, 22...
Adjustment screw, 23...cylindrical part, 24... hollow part.

Claims (1)

[Scope of utility model registration request] A valve chamber 19 is provided in the middle of an idle bypass passage 18 that connects the upstream and downstream sides of the throttle valve 17 in the intake passage 16.
A thin annular seat portion 25 is provided at the inlet side opening end of the valve chamber 19 of No. 8, and an adjusting screw 22 is provided with a valve body 21 having a thin cylindrical portion 23 with an open end surface.
is provided by inserting the valve body 21 into the valve chamber 19 orthogonally to the seat portion 25, and the valve body 2
The LPG mixer is configured such that the outer circumferential surface of the sheet portion 1 partially closes the sheet portion 25.