JPS6243066B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to LPG for internal combustion engines used in automobiles, etc.
This paper concerns improvements to vaporizers.

FIG. 1 is a sectional view of a conventional vaporizer known from Japanese Utility Model Application Publication No. 47-29118. This vaporizer 1 includes an atmospheric chamber 2, a first negative pressure chamber 3, and a vaporization chamber 4.
The first negative pressure chamber 3 introduces the negative pressure generated in the bench lily portion 21 of the mixer 20. LPG taken out in liquid form from a cylinder (not shown) flows into the primary valve 9, and when the primary lever 16 opens the primary valve 9, it flows into the vaporization chamber 4 and is vaporized. This vaporized LPG gas passes through the secondary valve 10 and is supplied to the bench lily section 21. The opening degree of the primary valve 9 is controlled by the primary diaphragm 6 that separates the vaporization chamber 4 and the second negative pressure chamber 5, and the opening degree of the secondary valve 10 is controlled by the atmospheric chamber 2.
It is controlled by a secondary diaphragm 7 that separates the first negative pressure chamber 3 from the first negative pressure chamber 3. That is, when the intake air amount of the mixer 20 is large and the negative pressure generated in the bench lily section 21 is large, the secondary diaphragm 7 compresses the secondary spring 15 and rotates the secondary lever 14 clockwise.
A large amount of LPG gas is introduced into the mixer 20 by increasing the opening degree of the secondary valve 10. When the pressure inside the vaporization chamber 4 becomes low, the primary diaphragm 6 rises and the force of the primary lever 16 sealing the primary valve 9 becomes weaker, so LPG flows through the primary valve 9 into the vaporization chamber 4. to go into.

The vaporizer 1 configured in this way controls the amount of fuel supplied by the opening degree of the secondary valve 10, but this alone does not allow the mixer 20 to operate over a wide range of operating ranges from idling to maximum speed.
It is difficult to control the amount of fuel supplied to the
For example, if the lift amount of the secondary valve 10 at maximum speed is set to 2 mm, the lift amount at idling will be about 0.05 mm. At this idling time, it is impossible to stably obtain such a lift amount mainly due to the rigidity of the secondary diaphragm 7. Therefore, the amount of fuel supplied was unstable.

In order to eliminate this drawback, the conventional vaporizer 1 is provided with the following correction means. That is, the idle lever 12 is installed in the atmospheric chamber 2,
Its tip is connected to the secondary diaphragm 7 via the idle spring 13, and the other end of the idle lever 12 is in contact with the tip of the idle screw 11. If this idle screw 11 is screwed in slightly to suppress the movement of the secondary diaphragm 7, the secondary diaphragm 7 will not move during idling when the negative pressure generated in the bench lily portion 21 is small. At this time, the secondary valve 10 is adjusted to maintain the minimum opening degree.

FIG. 3 is a diagram showing the relationship between the intake air amount and fuel flow rate of the vaporizer shown in FIG. 1. dashed line 1
7 shows the relationship to obtain the ideal mixture air-fuel ratio,
The intake air amount and fuel flow rate are proportional. However, as described above, when a correction means for correction during idle operation is provided, the fuel flow rate is constant as shown by the solid line 18 until the intake air amount reaches x, and after that, the secondary diaphragm 7 , and rotate the secondary lever 14 clockwise to increase the opening degree of the secondary valve 10. Therefore, when the amount of intake air is x or more, the relationship is as shown by solid lines 19a and 19b. Note that the solid line 19a shows the case where the opening degree of the secondary valve 10 is controlled so as to match the ideal dashed-dotted line 17 when the amount of intake air is moderate, and the solid line 19b shows the case where it matches the ideal dash-dotted line 17 when the amount of intake air is large. This is the case when

If the fuel supply amount is kept constant during idling in this way, the mixture becomes lean, and when the point Decrease. That is, although the engine has the advantage of being able to maintain a stable operating condition at the initial stage of idling, it has the disadvantage that the range in which a suitable air-fuel mixture can be obtained during other periods of operation is limited.

An object of the present invention is to provide an LPG vaporizer for an internal combustion engine that is suitable for supplying a proper air-fuel mixture over the entire operating range, and is characterized by a vaporizing chamber, a first negative pressure chamber, and a first negative pressure chamber. A slow valve is installed in parallel with the secondary valve on the bulkhead that separates the valve, and during idling operation, the opening degree of the slow valve is changed in proportion to the negative pressure in the negative pressure chamber, and during normal operation when the secondary valve starts to open, The reason is that the slow valve is designed so that the amount of fuel passing through it is constant.

Generally, when controlling the flow rate by changing the opening area of a valve, if the opening diameter of the valve is made smaller, the amount of movement of the valve becomes larger, making it possible to precisely adjust even a small flow rate.

FIG. 2 is a sectional view of a vaporizer according to an embodiment of the present invention, in which the same parts as in FIG. 1 are denoted by the same reference numerals. The difference from FIG. 1 is that a slow valve 23 with a small opening diameter is provided on the wall separating the first negative pressure chamber 3 and the vaporization chamber 4, and when idling, the slow valve 23 opens and the intake air is The aim was to ensure that fuel was supplied in an appropriate amount. That is, a slow lever 24 that opens and closes the slow valve 23 is supported by a fulcrum provided by extending the fulcrum of the secondary lever 14, and a slow spring 22 that adjusts the closing force of the slow valve 23 is attached to the left end of the slow lever 24. It is locked to the idle screw 11. Further, the right end of the throw lever 24 is in contact with the tip of a contact 25a fixed to the center of the secondary diaphragm 7, and a connector 25b is attached to the right end of the throw lever 24. This connector 2
5b becomes 2 when the intake air amount of the mixer 20 becomes large.
Next, the right end of the lever 14 is pushed down.

FIG. 4 is a diagram showing the relationship between the intake air amount and fuel flow rate of the vaporizer shown in FIG. 2. A broken line 26 indicates the slow fuel flow rate passing through the slow valve 23, and a solid line 27 indicates the fuel flow rate supplied from the secondary valve 10. Therefore, the bench lily portion 21 passes through the slow valve 23 and the secondary valve 10.
The fuel flow rate supplied to the engine is within the range between the parallel lines 28, and a fuel amount proportional to the intake air amount is supplied over the entire operating range.

In FIG. 2, the connector 25b and the secondary lever 1
4 is formed with a gap (not shown, such as the gap between the spring 29 and the secondary lever 14 in FIG. 5), which controls the displacement of the secondary diaphragm based on the amount of intake air at idle rotation. As such, when the displacement is small, the connector 25 crosses the gap between the connector 25b and the secondary lever 14.
b cannot reach the secondary lever 14. Therefore, this vaporizer 1 is 2 when idling.
The next valve 10 does not open, and the slow valve 23
The valve is then opened by the diaphragm 7. The slow valve 23 is attached to the tip of a small diameter pipe,
Since the opening area is small, after reaching the fuel flow rate (intake air amount x), the fuel flow rate is constant as shown by the broken line 26 in balance with the flow path resistance. Further, the secondary valve 10 is closed by the spring force of the secondary spring 15 until the amount of intake air reaches x, and after that, the secondary spring 15 is compressed and the opening degree of the secondary valve 10 is controlled by the bench lever. Part 21
Increase in proportion to the negative pressure. This operation is achieved by appropriately selecting the characteristics of the secondary diaphragm 7, secondary spring 15, and slow spring 22, as well as the opening diameters of the secondary valve 10 and slow valve 23, as shown in FIG. We are trying to obtain comprehensive characteristics. Note that the spring force of the slow spring 22 can be changed by adjusting the screwing position of the idle screw 11.

As described above, the vaporizer of this embodiment has stability during idling operation by installing a small diameter pipe in parallel with the secondary valve and opening the slow valve attached to the tip of the pipe according to the intake air amount of the mixer. can be improved. Additionally, when the secondary valve opens, a constant amount of fuel passes through the slow valve due to the flow path resistance of the small diameter pipe, resulting in the effect that a suitable amount of fuel can be supplied to the mixer over the entire operating range. It will be done.

FIG. 5 is a diagram illustrating a throw lever that is a modification of the one shown in FIG. 2, in which a spring 29 is attached to the right end of the throw lever 24. In this way, the impact of pushing the secondary lever 14 can be alleviated, so that the secondary valve 10 can be opened more smoothly than when the contactor 25b of FIG. 2 is used.

FIG. 6 is a diagram illustrating a throw lever as yet another modification, in which an adjustment screw 30 is attached to the right end of the throw lever 24. In this way, it becomes possible to adjust the timing at which the secondary lever 14 is pressed, that is, the position where the solid line 27 in FIG. 4 intersects with the horizontal axis. It has the advantage of being

As described above, the LPG vaporizer for internal combustion engines of the present invention has the following features:
This has the effect of supplying an appropriate air-fuel mixture to the internal combustion engine over the entire operating range.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional vaporizer, FIG. 2 is a sectional view of a vaporizer according to an embodiment of the present invention, and FIG. 3 is a line showing the relationship between the intake air amount and fuel flow rate of the vaporizer in FIG. 1. 4 are diagrams showing the relationship between the intake air amount and fuel flow rate of the vaporizer of FIG. 2, and FIGS. 5 and 6 are explanatory diagrams of a slow lever that is a modification of FIG. 2. DESCRIPTION OF SYMBOLS 1...vaporizer, 2...atmospheric chamber, 3...first negative pressure chamber, 4...vaporization chamber, 5...second negative pressure chamber, 6...primary diaphragm, 7...secondary diaphragm, 9...primary valve, 10...Secondary valve, 14...Secondary lever,
15... Secondary spring, 20... Mixer, 21... Bench lily part, 22... Slow spring, 23... Slow valve, 24... Slow lever, 25... Contact, 29... Spring, 30... Adjustment screw.

Claims (1)

[Claims] 1. A vaporization chamber into which LPG taken out in liquid form from a cylinder is introduced and vaporized, a negative pressure chamber communicating with the bench lily of the mixer, and a partition wall separating this negative pressure chamber and the vaporization chamber. In an LPG vaporizer for an internal combustion engine configured to adjust the opening degree of a secondary valve, a slow valve is provided in the partition wall in parallel with the secondary valve, and during idling operation, the opening degree of the slow valve is adjusted to the negative pressure chamber. LPG for an internal combustion engine, characterized in that the amount of fuel passing through the slow valve is constant during normal operation when the secondary valve starts opening. vaporizer. 2. The slow valve allows a constant amount of fuel to pass through due to the flow resistance of the fuel flow path itself even when the opposing throw lever rotates and its opening changes during normal operation of the internal combustion engine. The LPG vaporizer for an internal combustion engine according to claim 1, which is a slow valve attached to the tip of a thin pipe. 3 The slow valve contacts the end of the secondary lever that opens and closes the secondary valve, and the fulcrum of the slow lever that is rotated by the secondary diaphragm that partitions the negative pressure chamber and the atmospheric chamber The LPG vaporizer for an internal combustion engine according to claim 1, which is a valve attached to the slow lever between the spring locking point and the slow lever.