JPH07208269A - Fuel feeding device for vehicle - Google Patents

Abstract

PURPOSE:To prevent the area of large engine load from being affected by providing a fuel circuit by the forcible feeding of the slow system and the starting system and a fuel circuit by the suction of the main system in an independent manner from each other, improve the startability of the engine, stabilize the idling, improve the fuel consumption and the engine output, and reduce the variance of the exhaust emission. CONSTITUTION:A main system fuel circuit 58 to feed the main system gas fuel from a secondary decompression chamber 16 of a regulator 4 to a mixer 6, and a slow system fuel circuit 60 to feed the slow system gas fuel from a primary decompression chamber 12 of the regulator 4 to the mixer 6 are provided. A starting system fuel circuit 62 to feed the starting system gas fuel from the primary decompression chamber 12 of the regulator 4 to the mixer 62 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular fuel supply system, and more particularly to a vehicular fuel supply system capable of improving startability and stabilizing idle operation in a CNG (compressed natural gas) engine.

[0002]

2. Description of the Related Art In a vehicle engine, a gasoline engine using gasoline, which is a liquid fuel, a LPG engine using LPG (liquefied petroleum gas), which is a gas fuel, or a CNG (compressed natural gas), is used as a fuel. To do C
There is an NG engine.

To these LPG and CNG engines, liquid gaseous fuel stored in a fuel tank is decompressed and supplied by a regulator of a fuel supply device.

As a fuel supply device for an LPG engine,
There is one shown in FIG. In FIG. 2, 102 is a fuel supply device, 104 is a regulator, and 106 is a mixer. Regulator 104 is a gas fuel (LP
The pressure of G) is constantly reduced. Mixer 106
The gas fuel (LPG) from the regulator 104 is mixed with air and supplied to an engine (not shown).

The regulator 104 includes a body 108.
A primary chamber decompression 110 is provided inside by partitioning with a primary diaphragm 112, and a gas fuel (L
A primary pressure reducing mechanism 114 for adjusting (PG) to the primary pressure is provided.

Further, the regulator 104 is provided with a secondary decompression chamber 118 which communicates with the primary decompression chamber 110 by a communication hole 116 and is partitioned by a secondary diaphragm 120, and a gas fuel (LPG) in the secondary decompression chamber 118 is provided. Is provided with a secondary pressure reducing mechanism 122.

Further, the regulator 104 is provided with a slow chamber 126 which is communicated with the primary decompression chamber 110 by a slow introduction hole 124 and is partitioned by a slow diaphragm 128. The slow chamber 126 is operated by negative pressure of intake air to operate gas fuel (LPG).
A slow adjustment mechanism 130 for adjusting the pressure to a slow pressure is provided.

This regulator 104 is provided in the secondary decompression chamber 1
The main system gaseous fuel adjusted to the secondary pressure of 18 is supplied to the main system of the mixer 106 and ejected from the main nozzle 132, and the slow system gaseous fuel adjusted to the primary pressure of the primary decompression chamber 110 is supplied. It is supplied to the slow system of the mixer 106 through the slow chamber 126 and ejected from the slow nozzle 134.

Further, the mixer 106 is provided with a mixer intake passage 138 in the main body 136.
A venturi 140 is provided at 38. A throttle valve 142 is provided on the downstream side of the venturi 140. The main nozzle 132 is provided in the venturi intake passage 144 of the venturi 140. A slow nozzle 134 is provided in the mixer intake passage 138 near the throttle valve 142.

The mixer 106 includes a regulator 104.
The gaseous fuel adjusted to the secondary pressure by the main nozzle 1
It is supplied to 32 and is ejected to the venturi intake passage 144.

That is, the regulator 104 not only has the function of simply reducing the pressure of the gaseous fuel (LPG) and maintaining the pressure of the gaseous fuel constant, but also has the function of controlling the air-fuel ratio of the slow system of the mixer 106. In addition, the function of coasting richer is required.

Further, as a regulator of a fuel supply device for a CNG engine, there are regulators shown in FIGS. In FIGS. 3 and 5, 202 is a fuel supply device and 204 is a regulator. The regulator 204 has a main body 206.
Primary decompression chamber 210 with primary diaphragm 208 inside
The secondary decompression chamber 214 is defined by the secondary diaphragm 212. Primary decompression chamber 21
0 is connected to the secondary decompression chamber 214 through a communication hole 216.

The primary decompression chamber 210 is provided with a primary decompression mechanism 218 for adjusting the gaseous fuel to a primary pressure.

The secondary decompression chamber 214 is provided with a secondary decompression mechanism 220 for adjusting the gaseous fuel to a secondary pressure.

As a result, the regulator 204 reduces the pressure of the gaseous fuel (CNG) supplied from the fuel tank to the primary pressure by the primary pressure reducing mechanism 218 and reduces the gas fuel (CNG) to the primary pressure by the primary pressure reducing mechanism 220.
Is reduced to a secondary pressure by the secondary pressure reducing mechanism 220 and supplied to a mixer (not shown).

In this regulator 204, when the mixer is a fixed venturi type, the amount of air passing through the venturi of the mixer is small at the time of engine start and idle operation, and therefore the intake negative pressure is low and the fuel Although it was not possible to obtain an appropriate air-fuel ratio (A / F) due to a slight suction, an appropriate amount of fuel was pumped directly from the primary decompression chamber 210 (about 0.3 kgf / 〓 ² gauge pressure) to the mixer. , Need to satisfy this. However, the regulator 104 in FIG. 2 described above has the above-described function.

When the regulator is used for a vehicle such as a scooter, the regulator 204 shown in FIG. 3 is used because the size of the regulator 104 in FIG. 2 is too large.

In the slow system of the regulator 204, as shown in FIG. 5, a solenoid valve 224 and a slow fuel adjusting mechanism 22 are provided in the middle of the slow system fuel passage 222.
6 and 6 are provided. The solenoid valve 224 opens when the engine key is turned on, and closes when the engine key is turned off. In the slow fuel adjusting mechanism 226, the slow fuel adjusting tool 228 is rotated to adjust the amount of slow system fuel.

Further, the main body 206 of the regulator 204 is provided with an idle adjuster 230 for adjusting the air-fuel ratio during idle operation.

Further, there is a fuel supply system for a CNG engine shown in FIG. In FIG. 6, 302 is an engine, 304 is a fuel supply device, 306 is an air cleaner, 308 is an intake manifold, and 310 is an intake passage. The intake manifold 308 is provided with a carburetor 312.

The carburetor 312 is connected to the other end of a fuel supply passage 316 whose one end is connected to the fuel tank 314.

In the fuel supply passage 316, a stop valve 318 having an overflow valve, a three-way connecting pipe 320, a solenoid valve 322, a first regulator 324, and a second regulator 326 are sequentially installed from the fuel tank 314 side. And are provided.

In addition, the three-way connecting pipe 320 has a filling passage 3
28 is connected. In the filling passage 328, a check valve 330 and a check valve 330 are sequentially provided from the side of the trifurcating connection pipe 320.
A closing valve 332 and a coupler 334 are provided.

A slow fuel passage 336, which communicates with the intake passage 310 on the downstream side of the carburetor 312, is connected to the second regulator 326.

The solenoid valve 322 is opened by turning on the engine key.

Further, the first regulator 324 includes
A fuel pressure gauge 338 is connected to detect the pressure of the fuel.

As shown in FIG. 7, the carburetor 312 has a mechanical structure, and when the valve body 340 moves up and down, the carburetor jet 34 in the venturi 342 is moved.
The gaseous fuel and the air jetted from the vaporizer nozzle 346 via 4 are mixed in an appropriate amount, and the mixture is supplied to the engine 302 side.

Further, as such a fuel supply device,
For example, Japanese Utility Model Laid-Open No. 2-131064 and JP-A-61-161
It is disclosed in Japanese Patent Publication No. 98955. Actual Kaihei 2-131
JP-A-064 discloses a cylinder for storing LP gas in a liquid state and a first solenoid valve for connecting and disconnecting a fuel line connecting a primary decompression chamber for decompressing the same gas under reduced pressure, and a primary decompression chamber and LP gas mixture. A second solenoid valve for connecting and disconnecting a slow fuel passage connecting the fuel cell and a start control means for opening both solenoid valves before cranking. The one disclosed in Japanese Patent Laid-Open No. 61-98955 has, in addition to the main fuel from the secondary pressure reducing chamber of the vaporizer (regulator) at the time of starting the LPG engine,
In a fuel supply method for facilitating the starting of an LPG engine by supplying slow-speed fuel to the intake passage via the slow-speed fuel supply valve, when the throttle valve is opened suddenly or greatly, the negative pressure in the intake passage is increased. For example, between the negative pressure working chamber of the diaphragm type slow speed fuel supply valve and the intake passage so that the operation of the slow speed fuel supply valve is stopped and the supply of slow speed fuel is not stopped, Provided with a negative pressure holding valve for holding the operation of the slow speed fuel supply valve regardless of the negative pressure in the intake passage, and stopping the slow speed fuel supply valve when the engine stalls or stops. An electromagnetic valve is provided between the negative pressure working chamber of the diaphragm type slow speed fuel supply valve and the atmosphere, and further, the operation of the negative pressure holding valve is blocked during cranking to supply the slow speed fuel. The negative pressure working chamber of the valve By providing a bypass passage for connecting to the intake air intake passage so that opening / closing can be controlled by a solenoid valve, the initial explosion of the engine during cranking can be facilitated and the engine can be easily started especially at low temperatures. At the same time, the engine is prevented from running when the engine is stopped.

[0029]

By the way, in the regulator 204 of FIG. 3, as described above, the regulator 104 of FIG. 2 does not have the function, and the idle adjusting screw 230 is rotated to adjust the valve setting pressure of the communication hole 216. The air-fuel ratio is adjusted instead.

However, when the air-fuel ratio of the slow system, that is, the idle system is adjusted by the idle adjuster 230 in this way, it has a great effect on the full opening of other load regions of the engine, and the carburetor cannot be set. As shown in FIG. 8, it affects not only the fuel consumption but also the engine output as well as the large engine load region, and the exhaust gas greatly varies, so that a vehicle of constant quality cannot be obtained. There is an inconvenience.

[0031]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a regulator having a primary decompression chamber and a secondary decompression chamber for adjusting the pressure of gaseous fuel. In a fuel supply device for a vehicle, which is provided with a mixer that mixes the gaseous fuel with air into an engine and supplies the main gaseous fuel from the secondary decompression chamber of the regulator to the mixer, A slow fuel circuit for supplying a slow gaseous fuel from the primary decompression chamber of the regulator to the mixer,
A starting system fuel circuit for supplying starting system gaseous fuel from the primary decompression chamber of the regulator to the mixer is provided.

[0032]

According to the structure of the present invention, when the engine is operated, gaseous fuel is discharged from the primary decompression chamber of the regulator into the starting system.
It is pumped in a proper amount to the mixer through the slow system fuel circuit.
On the other hand, in other engine load operation, for example, in steady operation, gaseous negative fuel is sucked from the secondary decompression chamber of the regulator through the main fuel circuit by the intake negative pressure generated in the mixer.

Further, when the engine is started, the starting system fuel circuit is activated along with the driving of the starting motor, and an appropriate amount of fuel is pressure-fed from the primary decompression chamber of the regulator.

As a result, the fuel circuit for pumping the slow system / starting system and the fuel circuit for sucking the main system can be separated independently, and it is possible to prevent the engine from having a large load. It is possible to improve engine startability, stabilize idle operation, improve fuel efficiency and engine output, and reduce variations in exhaust gas.

[0035]

Embodiments of the present invention will be described in detail and specifically with reference to the drawings. In FIG. 1, 2 is a fuel supply device for a CNG (compressed natural gas) engine (not shown), 4
Is a regulator, and 6 is a mixer.

In the regulator 4, the primary diaphragm 10 defines a primary decompression chamber 12 in the main body 8 and the secondary diaphragm 14 defines a secondary decompression chamber 16. About 0.3 kgf in the primary decompression chamber 12.
/ ¬ ² gauge pressure is maintained. The secondary decompression chamber 16 holds 0 to −10 〓 Ag which is slightly lower than the atmospheric pressure.

A primary decompression mechanism 18 is provided in the primary decompression chamber 12. The primary pressure reducing mechanism 18 is used for the fuel inlet 2
0 for opening and closing the primary valve body 22 and the primary valve body 2 on one end side
It has a primary lever 26 to which 2 is attached and swings around the fulcrum portion 24, and a primary spring 28 and a secondary spring 30 provided on the other end side of the primary lever 26.

A secondary decompression mechanism 32 is provided in the secondary decompression chamber 16. This secondary decompression mechanism 32 is used in the primary decompression chamber 12
And a secondary decompression chamber 16 to communicate with each other, a secondary valve body 36 that opens and closes the communication hole 34, a secondary lever 38 having the secondary valve body 36 attached to one end, and a secondary lever 38. A secondary spring 39 for elastically holding one end of the next lever 38,
It comprises a vacuum diaphragm 40 connected to the other end of the secondary lever 38, and a vacuum lock spring 42 engaged with the vacuum diaphragm 40.

A main jet 44 and a main nozzle 46 are provided in communication with each other in the air-fuel mixture 6, and a slow jet 48 and a slow nozzle 50 are provided in communication with each other. Further, the main jet 44 and the slow jet 4 are provided.
8 has a mixer fuel passage 52 communicating with A connecting passage 56 formed by a connecting pipe 54 communicates with the mixer fuel passage 52.

A main system fuel circuit 58, a slow system fuel circuit 60, and a starting system fuel circuit 62 are provided between the regulator 4 and the air-fuel mixture 6.

The main system fuel circuit 58 has a main fuel passage 64, one end of which communicates with the secondary decompression chamber 106 and the other end of which communicates with the connection passage 56, and supplies the main system gaseous fuel to the mixer 6. It is a thing.

The slow fuel passage 60 has a slow fuel passage 70, one end of which communicates with the connecting bolt 66 and communicates with the primary decompression chamber 12, and the other end of which communicates with the connecting portion 68 in the middle of the main fuel passage 64. It has a slow fuel adjustment mechanism 72 provided in the slow fuel passage 70. The slow fuel adjusting mechanism 72 has an idle adjuster fuel 74 and supplies a slow-system gaseous fuel to the mixer 6.

A negative pressure valve 76 is provided in the slow fuel passage 70 between the connecting bolt 66 and the idle adjuster screw 74. The negative pressure valve 76 includes a diaphragm 82 that forms a negative pressure chamber 80 in a main body 78,
The slow fuel passage 70 is fixed to the diaphragm 82.
The valve body 84 for opening and closing the valve 8 and the diaphragm 8 in the negative pressure chamber 80.
And a spring 86 for pressing 2. The negative pressure valve 76 is operated by the negative pressure of the intake air to operate the slow fuel passage 7
It opens and closes 0.

The starting system fuel passage 62 has one end communicating with the slow fuel passage 70 between the negative pressure valve 76 and the idle adjuster clutch 4 and the other end communicating with the slow fuel passage 70 between the adjuster clutch 4 and the connecting portion 68. The starting fuel passage 88 and the starting fuel adjusting mechanism 90 provided in the starting fuel passage 88 are provided, and the gaseous fuel is supplied to the mixer 6. The starting fuel adjusting mechanism 90 includes a solenoid valve 92 and a fixed jet 94 provided in a starting fuel passage 88 downstream of the solenoid valve 92.

The solenoid valve 92 is opened when a starting motor (not shown) is driven.

The fixed jet 94 is formed to have a predetermined diameter D so that an appropriate amount of gaseous fuel can pass through.

Next, the operation of this embodiment will be described.

When the engine is started, that is, before the starting motor is driven and the engine can operate, the solenoid valve 92 is opened together with the driving of the starting motor, and the negative pressure valve is caused by the intake negative pressure. 76 opens. As a result, the fuel of the starting system from the primary decompression chamber 12 of the regulator 4 is pressure-fed to the middle of the main fuel passage 64 via the slow fuel passage 70 and the starting fuel passage 88,
Then, it is supplied to the engine through the mixer 6.

At this time, in the starting system fuel circuit 62, the amount of fuel in the starting system is appropriately adjusted by the movement of the solenoid valve 92 and the fixed jet 94. Further, since the secondary decompression chamber 16 has substantially the same atmospheric pressure, no fuel is supplied from the main fuel passage 64.

Therefore, when the engine is started, the gaseous fuel is supplied to the engine from the primary decompression chamber 12 of the regulator 4 through the slow fuel passage 70 and the starting fuel passage 88 in an appropriate amount, so that the startability is improved. You can

When the engine is in the idle operation, the drive of the starting motor is stopped, so that the solenoid valve 92 is closed and the primary decompression chamber 12 of the regulator 4 is closed.
The slow-system gaseous fuel from (1) is pumped only from the slow fuel passage 70. The amount of fuel in the slow fuel passage 70 is
It is kept constant by the idle adjuster 74. As a result, the stability of the engine during idle operation can be improved.

When the engine is operated under another load, for example, in a steady operation, the intake negative pressure becomes small and the negative pressure valve 76 closes to close the slow fuel passage 70, and at the same time, occurs in the mixer 6. Due to the intake negative pressure, the main system gaseous fuel is sucked from the secondary decompression chamber 16 of the regulator 4, and this fuel is supplied to the engine through the mixer 6.

Therefore, in this operation, the fuel is not introduced from the slow fuel passage 70, the fuel amount is prevented from increasing excessively, the fuel consumption and the engine output are improved,
This makes it possible to stabilize the quality of the vehicle and prevent variations in exhaust gas.

That is, in this embodiment, for the purpose of mounting the small regulator 4 on the vehicle, the idle, that is, the setting of the slow system air-fuel ratio and the setting of the main system air-fuel ratio are made independent of each other, and the startability is improved. It is possible to stabilize the idle operation, improve fuel efficiency and engine output, reduce variations in exhaust gas, and reduce the cost.

Further, since the starting fuel adjusting mechanism 90 is provided with the solenoid valve 92 and the fixed jet 94, the amount of fuel at the time of starting is properly adjusted and the structure is simple.

[0056]

As is apparent from the above detailed description, according to the present invention, the main fuel circuit for supplying the main gas fuel from the secondary decompression chamber of the regulator to the mixer is provided.
The slow system fuel circuit that supplies the slow system gas fuel from the regulator's primary decompression chamber to the mixer and the start system fuel circuit that supplies the starting system gas fuel to the mixer from the regulator's primary decompression chamber The fuel circuit for pumping the system / starting system and the fuel circuit for sucking the main system can be independently separated, preventing the influence of the engine load to a large area and improving the engine startability. Along with stabilizing idle operation,
It is possible to improve fuel efficiency and engine output, and reduce variations in exhaust gas.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a fuel supply device.

FIG. 2 is a fuel supply device for a conventional LPG engine.

FIG. 3 is a cross-sectional view of a conventional CNG engine regulator.

FIG. 4 is a front view of the regulator of FIG.

5 is a system configuration diagram of a fuel supply device using the regulator of FIG.

FIG. 6 is a system configuration diagram of a fuel supply device for a conventional CNG engine.

FIG. 7 is an enlarged sectional view of the vaporizer shown in FIG.

FIG. 8 is a diagram showing the influence of rotation of the idle adjuster clutch on each load operation.

[Explanation of symbols] 2 Fuel supply device 4 Regulator 6 Mixer 12 Primary decompression chamber 16 Secondary decompression chamber 58 Main fuel circuit 60 Slow system fuel circuit 62 Starting system fuel circuit 74 Idle adjustment task 76 Negative pressure valve 92 Solenoid valve 94 Fixed jet

[Procedure amendment]

[Submission date] March 4, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area F02M 21/06 M

Claims (5)

[Claims] 1. A vehicle provided with a regulator having a primary decompression chamber and a secondary decompression chamber for adjusting the pressure of the gaseous fuel, and provided with a mixer for mixing the gaseous fuel from the regulator with air and supplying it to the engine. In the fuel supply device for a vehicle, a main system fuel circuit for supplying a main system gaseous fuel from the secondary decompression chamber of the regulator to the mixer is provided, and a slow system gaseous fuel is supplied to the mixer from the primary decompression chamber of the regulator. A fuel supply device for a vehicle, wherein a slow system fuel circuit is provided and a start system fuel circuit is provided to supply a starting system gaseous fuel from the primary decompression chamber of the regulator to the mixer. 2. The main fuel circuit has a main fuel passage, one end of which communicates with a secondary decompression chamber of the regulator and the other end of which communicates with a main nozzle and a slow nozzle of the mixer. The fuel supply system for a vehicle according to claim 1. 3. The slow fuel passage, wherein one end side communicates with the primary pressure reducing chamber of the regulator and the other end side communicates with the middle of the main fuel passage,
The fuel supply device for a vehicle according to claim 1, further comprising a slow fuel adjustment mechanism provided in the slow fuel passage. 4. The starter fuel circuit has one end communicating with the slow fuel passage upstream of the slow fuel adjusting mechanism and a second end downstream of the slow fuel adjusting mechanism to bypass the slow fuel adjusting mechanism. 2. The fuel supply device for a vehicle according to claim 1, further comprising a starting fuel passage communicating with the slow fuel passage on the side, and a starting fuel adjusting mechanism provided in the starting fuel passage. 5. The starting fuel adjusting mechanism includes a solenoid valve that opens when a starting motor is driven, and a fixed jet provided in the starting fuel passage downstream of the solenoid valve. The vehicle fuel supply device according to claim 4.