JPH05133295A - Fuel supply device for vehicle engine - Google Patents

Abstract

PURPOSE:To improve engine starting by controlling actuation of an electromagnetic change-over valve to communicate mutually a second flow path and a third fuel flow path when an ignition switch is 'on' and engine temperature is a set valve or higher and thereby cooling a fuel injection valve etc. CONSTITUTION:When an engine 2 is being started and cooling-water temperature as engine temperature is high beyond a set value, a fuel pump 46 is operated for a set time of 'on' of an ignition switch 68, so that a fuel supply path 34 and a second fuel flow path 58 are mutually communicated, bypassing a fuel pressure regulator 14, there by circulating forcefully fuel. Accordingly, vapor occurring in fuel paths, such as the fuel supply path 34, is removed and also a fuel injection valve 12 and a delivery pipe 10 are effectively cooled with low-temperature fuel, so that starting of the engine 2 is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply system for a vehicle engine, and more particularly, to positively remove the vapor in the fuel passage at the time of high temperature start of the internal combustion engine and to cool the fuel injection valve and the like. The present invention relates to a fuel supply device for a vehicle engine that can improve startability.

[0002]

2. Description of the Related Art In a vehicle engine, the fuel in a fuel tank pumped by a fuel pump is adjusted to a constant pressure by a fuel pressure regulator to act on a fuel injection valve, and the fuel is supplied from this fuel injection valve. Some are provided with a supply device.

That is, as shown in FIG. 7, the fuel tank 202
The fuel inside is sucked up by the fuel pump 204 and sent under pressure from the fuel supply passage 208 formed by the fuel supply pipe 206 to the plurality of fuel injection valves 210. The fuel injection valve 210 is attached to the delivery pipe 212 and connected to the engine 214 to supply fuel to the engine 214. An intake manifold (not shown) is connected to the engine 214. A surge tank 216 and a throttle body 218 are connected to the intake manifold on the upstream side.

At one end of the delivery pipe 210,
A fuel pressure regulator 220 that keeps the fuel pressure to the fuel injection valve 210 constant is provided. This fuel pressure regulator 220, as shown in FIG.
On one end side of the fuel chamber 230 formed by the pressure chamber 224 formed by the diaphragm 222, the spring 226 that presses the diaphragm 222 to expand the pressure chamber 224, and the partition body 228 installed in the delivery pipe 212. And the intake pipe pressure from the pressure introduction passage 234 formed by the pressure introduction pipe 232 is
It works by acting on. The diaphragm 2
A valve body 236 is fixedly installed at the central portion of 22.

Further, in the delivery pipe 212, a fuel supply side passage 240 is formed by the fuel supply side pipe 238 so as to communicate with the fuel supply passage 208, and the fuel supply pipe 238 and the delivery pipe 212 are connected to each other. A return path 242 for returning the fuel is formed. One end of the fuel supply side passage 240 on the fuel pressure regulator 220 side is closed by the partition body 228. Also,
The partition body 228 closes a part of the return path 242. The return passage 242 and the fuel chamber 230 are connected by a communication passage 244.

Further, in order to recirculate excess fuel when the fuel pressure is adjusted by the fuel pressure regulator 220,
Fuel recirculation passage 24 formed by fuel recirculation pipe 246
8 are provided. The opening 250, which is one end of the fuel recirculation passage 248, is opened and closed by the valve body 236. The other end of the fuel return pipe 246 is opened inside the fuel tank 202.

Further, as shown in FIG. 9, in the fuel supply device 302 of the multi-point injection system, the fuel injection valve 310 attached to the delivery pipe 308 is connected to the cylinder head 306 of the engine 304, and the delivery pipe 308. One side of the surge tank 31
Fuel pressure regulator 3 operated by intake pipe pressure from 2
14 is attached. In addition, the delivery pipe 30
8 is connected to a fuel supply passage 320 for guiding the fuel pumped by the fuel pump 318 in the fuel tank 316. Further, when the fuel pressure is adjusted by the fuel pressure regulator 314, excess fuel is recirculated into the fuel tank 316 by the fuel recirculation passage 316.

In the fuel supply device 302 described above,
When the ignition switch is turned on, the fuel pump 318 is operated only for 2 to 3 seconds, the fuel pressure up to the fuel pressure regulator 314 in the fuel supply passage 320 is raised in advance, and the startability of the engine 304 is improved.

Further, as an engine fuel supply system,
For example, Japanese Utility Model Laid-Open No. 60-171937, Japanese Utility Model Laid-Open No. 61-
No. 17472 and Japanese Utility Model Laid-Open No. 63-183473. The one disclosed in Japanese Utility Model Laid-Open No. 60-171937 has a structure in which a solenoid valve for closing the fuel passage when the engine is started is provided in the fuel passage between the pressure regulator and the injector. Further, the one described in Japanese Utility Model Laid-Open No. 61-17472 discloses a valve in which a return line is branched from a wake position of a pressure regulator into first and second passages, and the first passage is closed when the engine is stopped. A device is arranged and a second pressure regulator having a set pressure higher than that of the pressure regulator is arranged in the second passage. In addition, the actual development 63-
The one described in Japanese Patent No. 183473 has an operating means for operating the three-way solenoid valve in a state of transmitting the second pressure fluid to the pressure responsive member under the condition that the pressures of the first and second pressure fluids are close to each other except during the specific operation. This is the configuration provided.

[0010]

However, in the conventional fuel supply system, the fuel pressure is previously increased in the fuel passage so that the fuel is immediately injected from the fuel injection valve when the engine is started. Since the purpose is to set the fuel pump, when the fuel pump is turned on, the fuel cannot actively circulate in the fuel passage, and for example, in the multipoint injection system, there is a problem that the fuel injection valve itself is heated, Due to the layout, when the engine is stopped at high temperature, vapor is likely to be generated in the delivery pipe and the fuel injection valve, and when the engine is started, vapor is injected and the air-fuel ratio becomes overrich, and the fuel supply passage is locked. However, there was an inconvenience that the startability deteriorated.

[0011]

Therefore, according to the present invention, in order to eliminate the above-mentioned inconvenience, the fuel pressure-fed to the fuel passage by the fuel pump is adjusted to a constant pressure by the fuel pressure regulator and acts on the fuel injection valve. In the fuel supply device for a vehicle engine for supplying fuel from the fuel injection valve to the engine, a first fuel recirculation passage for recirculating the fuel after the fuel pressure is adjusted by the fuel pressure regulator is provided, and the fuel passage A second fuel recirculation passage for bypassing the fuel pressure regulator to recirculate fuel, and an electromagnetic switching valve for switching between the first fuel recirculation passage and the second fuel recirculation passage. Is connected to a third fuel return passage for returning fuel to the fuel tank, and the second fuel return passage is provided when the ignition switch is turned on and the engine temperature is equal to or higher than a set value. Characterized in that a control means for controlling operation of the electromagnetic switching valve to pass communication between the a passage third fuel recirculation passage.

[0012]

According to the structure of the present invention, when the ignition switch is on and the engine temperature is higher than the set value, the electromagnetic switching valve operates so as to connect the second fuel recirculation passage and the third fuel recirculation passage. Therefore, the fuel is actively circulated in the fuel passage, which removes the vapor in the fuel passage, cools the fuel injection valve, etc., and causes a problem such as an air-fuel ratio becoming overrich. Can be prevented and the startability can be improved.

[0013]

Embodiments of the present invention will now be described in detail and specifically with reference to the drawings. 1 to 6 show an embodiment of the present invention. In FIG. 1, 2 is a vehicle engine, 4 is a fuel supply device, 6 is a throttle body, 8 is a surge tank, and 10 is a delivery pipe. A plurality of fuel injection valves 12 connected to the engine 2 are attached to the delivery pipe 10.

A fuel pressure regulator 14 for adjusting the fuel pressure to the fuel injection valve 12 to a constant value is provided at one end of the delivery pipe 10. As shown in FIG. 2, the fuel pressure regulator 14 includes a pressure chamber 18 defined by a diaphragm 16, a fuel chamber 22 defined by the diaphragm 16 and a partition body 20, and an expansion of the pressure chamber 18 by the diaphragm 16. And a spring 24 that presses in the direction, and operates by the intake pipe pressure acting on the pressure chamber 18 from the pressure introduction passage 28 formed by the pressure introduction pipe 26. A valve body 30 is attached to the central portion of the diaphragm 16.

The delivery pipe 10 is shown in FIG.
As shown in FIG. 1, one end side of the fuel supply passage 34, which is one of the fuel passages formed by the fuel supply pipe 32, is located at
The fuel supply side pipe 38, which is one of the fuel passages formed by the fuel supply side pipe 36 that is oriented in the axial direction of 0, communicates with the fuel supply side pipe 36 and the delivery pipe 10. A return path 40 is formed.
One side of the return side passage 40 and one end side of the fuel supply side passage 38 are closed by the partition body 20. The return passage 40 and the fuel chamber 22 are communicated with each other by a communication passage 42.

The other end of the fuel supply pipe 32 is, as shown in FIG. 1, a fuel pump 46 installed in a fuel tank 44.
It is connected to the. A fuel filter 48 is provided in the middle of the fuel supply pipe 32.

In the fuel chamber 22, the first fuel return pipe 5
An opening 54 on one end side of the first return passage 52 formed of 0 is opened. The opening 54 of the first fuel recirculation passage 52
Is opened and closed by the valve body 30. The first fuel recirculation passage 52 recirculates the excess fuel after the fuel pressure is adjusted by the fuel pressure regulator 14.

Further, one end side of a second fuel recirculation passage 58 formed by the second fuel recirculation pipe 56 is connected to one side of the delivery pipe 10 forming the fuel adjustment chamber 22. The second fuel recirculation passage 58 bypasses the fuel pressure regulator 14 from the fuel chamber 22 to recirculate the fuel.

The other end of the first fuel recirculation passage 52 and the second end
An electromagnetic switching valve (solenoid valve) 60 for switching between the first fuel recirculation passage 52 and the second fuel recirculation passage 56 is provided on the other end side of the fuel recirculation passage 56.

Further, a third fuel recirculation passage 64 formed by a third fuel recirculation pipe 62 is connected to the electromagnetic switching valve 60. The other end side of the third fuel recirculation passage 64 opens into the fuel tank 44.

This electromagnetic switching valve 60 is a control means (EC
U) 66. The control means 66 includes the fuel pump 46 and an ignition switch 68.
The cranking switch 70, the ignition coil 72, and the water temperature sensor 74 that detects the temperature of the cooling water of the engine 2 are connected to each other. A battery 76 is connected to the ignition switch 68.

As shown in FIG. 3, the control means 66 controls the second fuel recirculation passage 5 when the ignition switch 68 is turned on and the engine temperature, for example, the cooling water temperature is above a set value.
8 and the third fuel recirculation passage 64 so as to communicate with each other, an electromagnetic switching valve 60
The first fuel recirculation passage 52 is turned on while the other is turned on.
And the third fuel return passage 64 to communicate with each other, the electromagnetic switching valve 60
To turn off.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

When the program is started in the control means 66 (step 102) and the ignition switch 68 is turned on (step 104), it is first judged whether or not the cooling water temperature T is lower than a set value T _O (step S104). Step 106).

Here, if the cooling water temperature T <the set value T _O and step 106 is YES, the fuel pump 46 is turned on as usual (step 108), and the cranking switch 70 is turned on. It is determined (step 110).

If NO at step 110, it is determined whether the on-time t of the fuel pump 46 has reached the set time to (step 112). This step 112
If NO in step 108, the process returns to step 108. on the other hand,
If YES in step 112, the fuel pump 46 is turned off (step 114), and the program ends (step 116).

If YES at step 110,
Start engine 2 (step 118), and
It is determined whether or not the ignition switch 68 is off (step 120), and if NO at step 120, this determination is continued, while if YES at step 120, the program ends (step 122).

By the way, if in step 106 of returns NO, ie, when the cooling water temperature T> setpoint T _o is the time of starting the engine 2 at high temperature, first, the electromagnetic switching valve 6
0 is turned on (step 124), the fuel pump 46 is turned on (step 126), and then it is determined whether or not the cranking switch 70 is on (step 1).
28).

If NO at step 128, it is determined whether the on-time t of the fuel pump 46 has reached the set time to (step 130). This step 130
If NO in step 124, the process returns to step 124. on the other hand,
If YES at step 130, the fuel pump 4
6 is turned off (step 132), and this program is ended (step 134). That is, as shown in FIG. 5, after the ignition switch 68 is turned on and a set time t _{sec has} elapsed, the fuel pump 46 and the electromagnetic switching valve 60 are connected.
Are turned off, and the fuel supply passage 34, the first fuel recirculation passage 52, and the third fuel recirculation passage 64 are _{kept for} the set time t _sec.
And actively circulate fuel.

If YES at step 128, the electromagnetic switching valve 60 is turned off (step 13).
6) Then, start the engine 2 (step 13
8) Then, it is determined whether or not the ignition switch 68 is off (step 120). If NO in step 120, this determination is continued while step 12
If 0 is YES, this program is ended (step 122). That is, as shown in FIG. 6, only the electromagnetic switching valve 60 is turned off at the time t _x within the set time t _sec ,
The fuel is actively circulated for the time t _x .

As a result, at the time of starting the engine 2, when the temperature of the cooling water, which is the engine temperature, is higher than the set value T _o , the fuel pump 46 is driven for the set time when the ignition switch 68 is on, Fuel pressure regulator 14
Since the fuel can be positively circulated by bypassing the fuel supply passage 34 and the second fuel recirculation passage 58, the fuel can be actively circulated in the fuel passage such as the fuel supply passage 34 even in the multi-point injection system. The generated vapor can be positively removed, and the fuel injection valve 1
2 and the delivery pipe 10 are effectively cooled by the low-temperature fuel, whereby the startability of the engine 2 can be improved.

[0032]

As is apparent from the above detailed description, according to the present invention, the first fuel recirculation passage for recirculating the fuel after the fuel pressure is adjusted by the fuel pressure regulator is provided, and the fuel pressure regulator is provided from the fuel passage. A second fuel recirculation passage is provided for recirculating the fuel by bypassing the
An electromagnetic switching valve for switching between opening and closing the fuel recirculation passage is provided, and a third fuel recirculation passage for recirculating fuel to the fuel tank is connected to the electromagnetic switching valve. When the ignition switch is on and the engine temperature is equal to or higher than the set value. By providing the control means for controlling the operation of the electromagnetic switching valve so that the second fuel recirculation passage and the third fuel recirculation passage are communicated with each other, when the ignition switch is on and the engine temperature is higher than the set value, The switching valve is the second
Since the fuel recirculation passage and the third fuel recirculation passage are operated to communicate with each other, the fuel is actively circulated in the fuel passage, thereby removing the vapor in the fuel passage and cooling the fuel injection valve and the like. Therefore, it is possible to prevent the occurrence of problems such as the air-fuel ratio becoming excessively rich and improve the engine startability.

[Brief description of drawings]

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

FIG. 2 is a sectional view of a fuel pressure regulator.

FIG. 3 is an explanatory diagram of a switching state of a flow path when an electromagnetic switching valve is turned on / off.

FIG. 4 is a flowchart of fuel supply control.

FIG. 5 is a time chart when the cranking switch is not turned on within a set time after the ignition switch is turned on.

FIG. 6 is a time chart when the cranking switch is turned on within a set time after the ignition switch is turned on.

FIG. 7 is a system configuration diagram of a conventional fuel supply device.

FIG. 8 is a sectional view of a conventional fuel pressure regulator.

FIG. 9 is a configuration diagram of a fuel supply device of a conventional multipoint injection system.

[Explanation of symbols]

 2 engine 4 fuel supply device 10 delivery pipe 12 fuel injection valve 14 fuel pressure regulator 34 fuel supply passage 46 fuel pump 52 first fuel recirculation passage 58 second fuel recirculation passage 60 electromagnetic switching valve 64 third fuel recirculation passage 66 control means 68 Ignition switch 70 Cranking switch 72 Ignition coil 74 Water temperature sensor

Claims (1)

[Claims] 1. A fuel supply for an engine for a vehicle, in which fuel pressure-fed to a fuel passage by a fuel pump is adjusted to a constant pressure by a fuel pressure regulator to act on a fuel injection valve, and the fuel is supplied to the engine from the fuel injection valve. In the device, there is provided a first fuel recirculation passage for recirculating the fuel after the fuel pressure is adjusted by the fuel pressure regulator, and a second fuel recirculation passage for recirculating the fuel bypassing the fuel pressure regulator from the fuel passage. An electromagnetic switching valve for switching between the first fuel recirculation passage and the second fuel recirculation passage is provided. A third fuel recirculation passage for recirculating fuel to the fuel tank is connected to the electromagnetic switching valve. When the ignition switch is turned on and the engine temperature is equal to or higher than the set value, the electromagnetic switching valve is actuated to control communication between the second fuel recirculation passage and the third fuel recirculation passage. A fuel supply device for a vehicle engine, comprising: