JPH022925Y2 - - Google Patents

Description

[Detailed explanation of the idea] B. Purpose of the invention E-1 Industrial application fields The present invention relates to a fuel supply system for an LPG engine.

A-2 Prior Art Conventionally, as shown in FIG. 2, as shown in FIG. 2, an auxiliary fuel passage 4 is branched from a main fuel passage 3 from a secondary decompression chamber 2b of a regulator 1, and its downstream opening 4a is connected to a downstream opening 4a of this type of device. The main fuel passage 3 is connected to the main fuel passage 3 downstream of the main fuel regulating valve 5, and an on-off valve 6 is provided in the auxiliary fuel passage 4, and the on-off valve 6 is controlled by a control cam 8 provided in association with the throttle valve 7. Opening/closing is controlled by a lever 9, and when the engine is idling, the on-off valve 6 is closed, and when the engine rotation is rising and the transition is from a low speed range to a high speed range, the on-off valve 6 is opened to increase the amount of fuel. Japanese Patent Publication No. 52-24609 discloses a system that improves the connecting performance of fuel and closes the on-off valve 6 again in the high-speed range to prevent the supply of an overly rich mixture and to provide economical fuel supply. has been proposed. Furthermore, for the same purpose, a method was proposed in Japanese Utility Model Publication No. 55-31231 in which the opening/closing control of the on-off valve as described above was performed using a circuit or electromagnet that electrically detects the load condition of the engine. ing.

A-3 Problems to be Solved by the Present Invention In the prior art described above, since the downstream opening 4a of the auxiliary fuel passage 4 is merged downstream of the main fuel regulating valve 5, in the high speed range, if the opening/closing valve 6
When the auxiliary fuel passage 4 is kept open, high vent valve negative pressure acts on the auxiliary fuel passage 4, and fuel is sucked out from the auxiliary fuel passage 4, resulting in a rich mixture. Therefore, in the high speed range, the on-off valve 6 is closed as described above, but the former, which uses a cam mechanism to control opening and closing, requires a precise cam mechanism and is difficult to match with the engine, and the latter However, there is a problem in that the opening/closing control mechanism is complicated and expensive.

Therefore, the present invention is a simple and inexpensive fuel supply system that improves the performance of the transition by supplying auxiliary fuel when the engine transitions from a low-speed range to a high-speed range, and that prevents the mixture from becoming too rich even in the high-speed range. It is an object of the present invention to solve the above-mentioned problems by making it possible to form a wafer.

B. Structure of the invention B-1. Means for solving the problems In order to solve the above-mentioned problems, the present invention provides a slow fuel passage 11 from the primary decompression chamber 2a of the two-stage decompression regulator 1, and In the case where the main fuel passage 3 is provided from the chamber 2b, the tip of the slow fuel passage 11 is joined to the upstream part of the main fuel regulating valve 5 provided in the main fuel passage 3, Further, the slow fuel passage 11 is provided with a bypass passage 13 that bypasses the regulating valve 12 provided in the slow fuel passage 11, and the bypass passage 13 is provided with an on-off valve 14 that opens and closes it.
The present invention is characterized in that the on-off valve 14 is opened and closed in conjunction with the throttle valve 7.

RO-2 Operation When the engine is idling, the on-off valve 14 is in a closed state, and slow fuel flows out from the slow fuel passage 11. Next, when the throttle valve 7 begins to open to increase the rotation of the engine, the on-off valve 14 opens. This increases the amount of slow fuel from the bypass passage 13 as well, improving the transition performance in the transition region from the low speed range to the high speed range of the engine. Next, when the engine reaches a high speed range, main fuel is supplied from the main fuel passage 3. At this time, the on-off valve 14 remains open. Therefore, fuel also flows out from the bypass passage 13, but since the bypass passage 13 opens upstream of the main fuel regulating valve 5, the effect of high vent pressure on the bypass passage 13 is small, so that the fuel flows out. The outflow amount is negligibly small compared to the total fuel flow rate. Therefore,
Even if a bypass passage 13 is opened in a high speed range, a superrich mixture is not generated.

RO-3 Embodiment Next, an embodiment of the present invention shown in FIG. 1 will be described.

Reference numeral 1 designates a two-stage pressure reduction type regulator 1, in which 2a is a primary pressure reduction chamber and 2b is a secondary pressure reduction chamber. Reference numeral 3 denotes a main fuel passage communicating with the secondary decompression chamber 2b, the tip of which is opened to the intake passage 10a of the mixer 10 through a fuel injection hole 3a. A main fuel regulating valve 5 is provided in the main fuel passage 3. A slow fuel passage 11 communicates with the primary decompression chamber 2a, and its tip communicates with the main fuel passage 3 at the upstream side of the main fuel regulating valve 5 through an open end 11a. Reference numeral 12 denotes a regulating valve for regulating slow fuel, which is provided in the slow fuel passage 11. 13
is a bypass passage whose upstream end communicates with the slow fuel passage 11 in the upstream part of the regulating valve 12, and its downstream end communicates with the slow fuel passage 1 in the downstream part of the regulating valve 12.
It is connected to 1.

Reference numeral 14 denotes an on-off valve that opens and closes the flow path of the bypass passage 13, and is always urged in the opening direction by a spring 15. 7 is a throttle valve, and an operating lever 16 is fixed to the throttle shaft 7a. The actuating lever 16 pushes up and closes the on-off valve 14 against the spring 15 when the throttle valve 7 is in an idle state, and moves down and closes the on-off valve 1 when the throttle valve 7 is opened.
4 is set to open by the load of a spring 15.

Next, the operation of this embodiment will be explained.

When the engine is idling, the on-off valve 14 is in a closed state, and the slow fuel from the primary decompression chamber 2a of the regulator 1 is metered by the regulating valve 12 through the slow fuel passage 11, and flows out into the main fuel passage 3 from the open end 11a. The fuel passes through the main fuel adjustment valve 5 and into the injection hole 3.
It is supplied into the mixer 10 from a. Next, when the throttle valve 7 of the mixer 10 starts to be opened to increase the rotation of the engine, the throttle shaft 7a
The actuating lever 16 fixedly rotates downward, and the opening/closing valve 14 is lowered by the load of the spring 15 and opened. As a result, the slow fuel in the slow fuel passage 11 also flows out of the bypass passage 13 that bypasses the regulating valve 12, increasing the amount of slow fuel flowing into the mixer 10. At this time, since the opening of the slow fuel passage 11 to the main fuel passage 3 and the opening of the bypass passage 13 to the slow fuel passage 11 are both upstream of the main fuel regulating valve 5, the vent lily negative pressure of the mixer 10 with respect to them is has little effect. However, since the slow fuel is pumped out by the primary pressure of the regulator, the adjustment amount of the regulating valve 12 and the bypass passage 13 are independent of the negative pressure in the vent lily.
Slow fuel corresponding to the opening area of is injected into the mixer 10. Therefore, the amount of fuel is increased in the transition region from the low speed range to the high speed region of the engine, and the transition performance can be improved. Next, when the engine reaches a high speed range, the fuel in the secondary pressure reducing chamber 2b of the regulator 1 is metered by the main fuel regulating valve 5 through the main fuel passage 3, and is supplied into the mixer 10 from the injection hole 3a. At this time, both the slow fuel passage 11 and the bypass passage 13 are open, but since both of these opening ends are located upstream of the main fuel regulating valve 5, the effect of the high negative pressure generated in the vent lily portion of the mixer 10 is There are few.

Therefore, the amount of fuel supplied from the slow fuel passage 11 and the bypass passage 13 is constant depending on the pressure in the primary decompression chamber 2a, the adjustment amount of the regulating valve 12, and the opening area of the bypass passage 13, regardless of the rotation of the engine. Moreover, the proportion of the increase in fuel amount from the bypass passage 13 is negligible with respect to the total fuel flow rate. Therefore, the on-off valve 14 of the bypass passage 13
Even if the valve is opened at high speeds, it does not produce an overly rich mixture.

C. Effect of the invention As described above, according to the invention, the amount of auxiliary fuel is increased in the transition region from the low speed range to the high speed range of the engine to improve the transition performance, and the fuel mixture does not become too rich even in the high speed range. The supply device can be configured by a simple operation of simply keeping the on-off valve provided in the bypass passage open while the opening degree of the throttle valve is above a predetermined value. Compared to a valve that opens and then closes again at a predetermined time, it is much easier to control the fuel for engine rotation, and the structure is simpler and cheaper than the conventional system that electrically detects the engine load condition. It has the advantage that it can be formed into

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing an embodiment of the present invention;
The figure is a side sectional view showing a conventional structure. 1...regulator, 2a...primary decompression chamber, 2b...
Secondary decompression chamber, 3... Main fuel passage, 5... Main fuel adjustment valve, 7... Throttle valve, 10... Mixer, 11
...Slow fuel passage, 12...Adjustment valve, 13...Bypass passage, 14...Opening/closing valve, 16...Operation lever.

Claims (1)

[Scope of utility model registration request] In a two-stage pressure reducing regulator 1 in which a slow fuel passage 11 is provided from the primary decompression chamber 2a and a main fuel passage 3 is provided from the secondary decompression chamber 2b, the tip of the slow fuel passage 11 is connected to the main fuel passage 3. On the other hand, a bypass passage 13 is provided in the slow fuel passage 11, which joins the upstream part of the main fuel regulating valve 5 provided in the main fuel passage 3, and further in the slow fuel passage 11, bypassing the regulating valve 12 provided in the slow fuel passage 11. The bypass passage 13 is provided with an on-off valve 14 for opening and closing it, and the on-off valve 14 is opened and closed in conjunction with the throttle valve 7.
Fuel supply system for LPG engine.