JP2002081354A - Fuel supply equipment of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide fuel supply equipment of an engine capable of surely performing the re-starting of the engine at a high temperature and facilitating the layout of piping. SOLUTION: The fuel in a fuel tank T is pressurized by a fuel pump 16 and supplied to the injector 13 of the engine E connected to the downstream of a feed passage 17. The feed passage 17 and the fuel tank T are connected parallel with each other through a first return passage 19 having a low-pressure pressure regulator 21L installed therein and a second return passage 20 having a high-pressure pressure regulator 21H installed therein. A stop valve 22 is installed in the first return passage 9 between the feed passage 17 and the low-pressure pressure regulator 21L. When the engine E is re-started at a high temperature, the stop valve 22 in the first return passage 19 is closed and fuel pressure is regulated by the high-pressure regulator 21H, and fuel vapor in the feed passage 17 is expelled by high-pressure fuel from the injector 13 to prevent the startability from being deteriorated by vapor lock.

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 an engine, which pressurizes a fuel in a fuel tank with a fuel pump and supplies the fuel to an engine injector connected downstream of a feed passage.

[0002]

2. Description of the Related Art A fuel supply device for such an engine is known from Japanese Patent Application Laid-Open No. 6-264839. In the above conventional fuel supply device for an engine, a first pressure regulator is interposed in a feed passage connecting a fuel pump provided in a fuel tank and an injector of the engine, and a first pressure regulator is connected to the fuel tank. A control valve is interposed in one return passage, and a second pressure regulator having a higher set pressure than the first pressure regulator is interposed in a second return passage connecting the downstream side of the injector and the fuel tank.

[0003] During normal operation of the engine, the control valve is opened and the first return passage is opened, so that the pressure of the fuel supplied to the injector is regulated by the first pressure regulator having a low set pressure, and the set pressure is high. The second pressure regulator does not function substantially. On the other hand, when the engine is restarted at a high temperature, the control valve is closed and the first return passage is closed, so that the first pressure regulator having a low set pressure does not function, and is supplied to the injector by the second pressure regulator having a high set pressure. The fuel pressure is regulated. As a result, the high-temperature fuel remaining in the vicinity of the injector is quickly discharged to the fuel tank through the second return passage, and the fuel vapor generated in the vicinity of the injector is quickly discharged from the injector by high pressure. Thus, the vapor lock is released, and the engine can be easily restarted at a high temperature.

[0004]

However, the above-mentioned prior art requires a relatively long second return passage for returning fuel from the injector to the fuel tank, so that a space for surrounding the second return passage is required. In addition, when the engine is restarted at a high temperature, high-temperature fuel near the injector flows into the fuel tank, so that the fuel temperature in the fuel tank increases.

The present invention has been made in view of the above circumstances, and has as its object to provide a fuel supply device for an engine that can reliably restart the engine at a high temperature and has simple piping. .

[0006]

According to the first aspect of the present invention, an engine connected to a downstream side of a feed passage by pressurizing fuel in a fuel tank by a fuel pump. In the fuel supply device for the engine that supplies the fuel to the injector, the feed passage and the inside of the fuel tank are connected in parallel by a first return passage provided with a low-pressure pressure regulator and a second return passage provided with a high-pressure pressure regulator, A fuel supply device for an engine is proposed in which an on-off valve is provided in a first return passage between a feed passage and a low-pressure pressure regulator.

According to the above construction, the first return passage and the second return passage connecting the feed passage and the inside of the fuel tank are provided with the low-pressure pressure regulator and the high-pressure pressure regulator, respectively. Since the on-off valve provided in the valve is opened, the fuel pressure is regulated by the low-pressure pressure regulator having the lower set pressure, and a sufficient fuel pressure necessary for normal operation of the engine can be generated. In addition, when the engine is restarted at a high temperature, the on-off valve provided in the first return passage is closed, so that the fuel is regulated by the high-pressure pressure regulator with the higher set pressure, and the fuel vapor in the feed passage is injected from the injector with the high-pressure fuel. It is possible to prevent the startability from being deteriorated due to the eviction and the vapor lock. Moreover, since the first and second return passages do not return fuel from near the injector, but return fuel from the middle of the feed passage, they are arranged inside the fuel tank or near the fuel tank to save space. In addition to savings, it is possible to prevent the fuel temperature in the fuel tank from rising due to the high-temperature return fuel.

According to the invention described in claim 2,
In a fuel supply device for an engine, which pressurizes fuel in a fuel tank with a fuel pump and supplies the fuel to an injector of an engine connected downstream of the feed passage, the feed passage and the inside of the fuel tank are provided with a low-pressure pressure regulator. The first return passage and the second return passage provided with the high-pressure pressure regulator are connected in parallel, and the feed passage is selectively connected to the first return passage or the second return passage via a flow passage switching valve. A fuel supply system for an engine is proposed.

According to the above configuration, the feed passage and the inside of the fuel tank are connected by the first return passage provided with the low-pressure pressure regulator and the second return passage provided with the high-pressure pressure regulator. Since the first return passage communicates with the feed passage by the valve, the fuel can be regulated by the low pressure regulator having the lower set pressure to generate a fuel pressure necessary and sufficient for normal operation of the engine. When the engine is restarted at a high temperature, the flow path switching valve connects the second return passage to the feed passage. Therefore, the fuel is regulated by the higher pressure regulator having the higher set pressure, and the fuel vapor in the feed passage is increased by the high pressure fuel. It is possible to prevent the startability from being deteriorated due to the vapor lock, which is expelled from the injector. Moreover, since the first and second return passages do not return fuel from near the injector, but return fuel from the middle of the feed passage, they are arranged inside the fuel tank or near the fuel tank to save space. In addition to savings, it is possible to prevent the fuel temperature in the fuel tank from rising due to the high-temperature return fuel.

According to the third aspect of the present invention,
In a fuel supply device for an engine which pressurizes fuel in a fuel tank with a fuel pump and supplies the fuel to an injector of an engine connected downstream of the feed passage, a variable pressure pressure is applied to a return passage connecting the feed passage and the inside of the fuel tank. An engine fuel supply device provided with a regulator is proposed.

According to the above configuration, since the variable pressure regulator is provided in the return passage connecting the feed passage and the inside of the fuel tank, the set pressure of the variable pressure regulator is reduced during normal operation of the engine. It is possible to generate sufficient fuel pressure necessary for normal operation. Also, when the engine is restarted at high temperature, by increasing the set pressure of the variable pressure regulator,
The fuel vapor in the feed passage is expelled from the injector by the high-pressure fuel, so that deterioration of the startability due to the vapor lock can be prevented. Moreover, since the return passage does not return fuel from near the injector, but returns fuel from the middle of the feed passage, they can be arranged inside the fuel tank or near the fuel tank to save space. Instead, it is possible to prevent the fuel temperature in the fuel tank from rising due to the high-temperature return fuel.

According to the invention described in claim 4,
In addition to the configuration of claim 3, the variable pressure regulator provided in the return passage includes a pressure regulator having a first valve opening pressure, a solenoid valve that opens and closes a return passage upstream of the pressure regulator, and a solenoid. A fuel supply device for an engine, comprising: a bypass passage bypassing a valve and connected to a pressure regulator; and a check valve provided in the bypass passage and having a second valve opening pressure is proposed.

According to the above configuration, if the solenoid valve is opened during normal operation of the engine, the check valve does not function, so that the set pressure of the variable pressure regulator becomes equal to the first valve opening pressure of the pressure regulator. When the solenoid valve is closed when the engine is restarted at a high temperature, the check valve provided in the bypass passage functions. Therefore, the set pressure of the variable pressure regulator is set to the first valve opening pressure of the pressure regulator and the second valve of the check valve. It becomes an added value with the valve opening pressure, and can be higher than the set pressure during the normal operation.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

First, a first embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 1, an intake port 1 formed in a cylinder head 11 of a four-cylinder engine E for an automobile.
2 are provided with injectors 13 respectively. A fuel pump 16 having a strainer 14 and a filter 15 is disposed inside the fuel tank T. A feed passage 17 extending from the fuel pump 16 branches into four delivery passages 18 and is connected to the injector 13. You. Inside the fuel tank T, a first return passage 19 and a second return passage 20 are branched from the feed passage 17, and the first return passage 19 is provided with a low-pressure pressure regulator 21L.
0 is provided with a high-pressure pressure regulator 21H. The set pressure of the low-pressure pressure regulator 21L is set to a fuel pressure sufficient for normal operation of the engine E, and the set pressure of the high-pressure pressure regulator 21H is set higher than that. The upstream side of the first return passage 19, that is, the feed passage 17 and the low-pressure pressure regulator 21
L is provided with an on-off valve 22.

When the on-off valve 22 is kept open during normal operation of the engine E and the feed passage 17 is communicated with the first return passage 19, the fuel pressure in the feed passage 17 is reduced by the low pressure pressure regulator 21L and the low pressure regulator 21L. It acts on both the high pressure regulator 21H. At this time, the high pressure regulator 21H having a high set pressure does not substantially function, and the fuel pressure in the feed passage 17 is regulated by the low pressure regulator 21L having a low set pressure. Fuel can be supplied at a sufficient pressure.

When the engine E is restarted at a high temperature, the on-off valve 2
When the first return passage 19 is cut off from the feed passage 17 by closing the valve 2 by excitation, the fuel pressure in the feed passage 17 is regulated by the high pressure regulator 21H having a high set pressure. Is supplied with fuel. Therefore, even if the fuel vapor stays in the delivery passage 18 and the feed passage 17 near the injector 13 due to the heat of the engine E, the fuel vapor is quickly pushed out of the injector 13 by the high fuel pressure, and the engine E is started smoothly. can do. Since the on-off valve 22 is closed after being opened for a certain period of time by a timer, for example, the fuel regulated by the low-pressure pressure regulator 21L can be supplied to the injector 13 after the engine E is started.

The first return passage 19 and the second return passage 20 extend from the downstream end of the feed passage 17 to the fuel tank T.
Since the fuel is returned from the upstream portion of the feed passage 17 instead of returning the fuel, the length of the passage can be shortened and the space can be reduced. Moreover, the first return passage 19 and the second
Return passage 20, low pressure pressure regulator 21
L, high pressure regulator 21H and on-off valve 2
2 is stored inside the fuel tank T, so that the space saving effect is further enhanced.

Next, a second embodiment of the present invention will be described with reference to FIG.

In the first embodiment, the second return passage 20 is always in communication with the feed passage 17 and the first return passage 19
Is connected to the feed passage 17 through the on-off valve 22, but in the second embodiment, the first return passage 19 and the second
The return passage 20 is selectively communicated with the feed passage 17 through the passage switching valve 23.

During normal operation of the engine E, the flow path switching valve 23
Is de-energized and the first return passage 19 is connected to the feed passage 1
7 and the second return passage 20 to the feed passage 1
7, the fuel pressure in the feed passage 17 is regulated by the low-pressure pressure regulator 21L provided in the first return passage 19 and having a low set pressure, so that the fuel is supplied to the injector 13 at a pressure necessary and sufficient for normal operation of the engine E. Can be supplied.

Also, when the engine E is restarted at a high temperature, the flow path switching valve 23 is excited to connect the second return path 20 to the feed path 17 and disconnect the first return path 19 from the feed path 17. Fuel pressure is second
Since the set pressure provided in the return passage 20 is regulated by the high-pressure pressure regulator 21H, the fuel is supplied to the injector 13 at a higher pressure than during normal operation. Therefore, the fuel vapor accumulated in the delivery passage 18 and the feed passage 17 close to the injector 13 with the high-pressure fuel is pushed out from the injector 13 and the engine E can be started smoothly. Flow path switching valve 23
For example, after the engine is excited for a certain time by the timer, it returns to the non-excitation state, so that the fuel regulated by the low-pressure pressure regulator 21L can be supplied to the injector 13 after the engine E is started.

According to the second embodiment, the same operation and effect as those of the first embodiment can be achieved.

Next, a third embodiment of the present invention will be described with reference to FIGS.

In the first and second embodiments, two return passages 19, 20 and two pressure regulators 21L, 21H are provided. In the third embodiment shown in FIG. And a single variable pressure regulator 21V. The variable pressure regulator 21V is used to set the set pressure to a low pressure and a high pressure.
By switching the set pressure to a low pressure during normal operation of the engine E, fuel can be supplied to the injector 13 at a necessary and sufficient pressure, and when the engine E is restarted at a high temperature, the set pressure is maintained for a certain time. By switching to only high pressure, the engine E can be started smoothly.

As is apparent from FIG. 4, the variable pressure regulator 21V is
, A solenoid valve 26, and a check valve 27. Housing 28 of normally open solenoid valve 26
An upstream portion of a return passage 24 extending from the feed passage 17 extends into the inside of the housing 28. A valve seat 29 formed at the end of the upstream portion of the return passage 24 has a housing 28.
31 driven by excitation of coil 30 housed in
The valve body 32 provided at the lower end of the seat can be seated. In the upstream portion of the return passage 24, a bypass passage 3 bypassing the solenoid valve 26 and continuing to the pressure regulator 25 is provided.
The check valve 27 provided in the bypass passage 33 includes a valve seat 34, a valve body 35, and a spring 36 for urging the valve body 35 in a direction of sitting on the valve seat 34. Is done.

The pressure regulator 25 includes a lower housing 37 communicating with the housing 28 of the solenoid valve 26, an upper housing 38 to which the internal pressure of the fuel tank T acts, a lower housing 37 and an upper housing 3.
8, a spring 40 housed in the upper housing 38 and biasing the diaphragm 39 downward, a valve body 41 fixed to the center of the diaphragm 39, and a return passage 2 extending into the lower housing 37.
4 and a valve seat 42 formed at the start end of the downstream portion.
The valve opening pressure of the pressure regulator 25 is set to P1, and the valve opening pressure of the check valve 27 is set to P2.

During normal operation of the engine E, the coil 30 of the normally open solenoid valve 26 is demagnetized to release the valve body 32
From the valve seat 29, and the pressure in the upstream portion of the return passage 24 is reduced by the diaphragm 3 of the pressure regulator 25.
9 The pressure is the pressure regulator 25
When the pressure reaches P1, which is the valve opening pressure of the valve, the diaphragm 39 moves upward against the resilience of the spring 40, and the valve body 41 separates from the valve seat 42. As a result, the set pressure of the variable pressure regulator 21V becomes It becomes P1.

On the other hand, when the engine E is restarted at a high temperature, the coil 30 of the normally open solenoid valve 26 is excited so that the valve body 32
When the pressure in the upstream portion of the return passage 24 reaches P2, the check valve 27 provided in the bypass passage 33 opens, and the pressure in the upstream portion of the return passage 24 further increases from P2. When the pressure increases and reaches P1 + P2, the pressure regulator 25 opens as described above. Therefore, the set pressure of the variable pressure regulator 21V when the engine E is restarted at a high temperature is set to P1 + P2 higher than P1 which is the set pressure during normal operation.
It can be.

Further, according to the present embodiment, the return passage 24
In addition, since the number of pressure regulators 21V is the minimum number of one each, the effect of reducing the space can be further enhanced.

Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof.

For example, in the embodiment, the return passages 19, 2
0, 24, pressure regulators 21L, 21H, 2
1 V, the on-off valve 22 and the flow path switching valve 23 are connected to the fuel tank T
Of the fuel tank T, but all or a part thereof can be arranged outside the fuel tank T.

[0034]

As described above, according to the first aspect of the present invention, the first return passage and the second return passage connecting the feed passage and the inside of the fuel tank respectively have a low pressure regulator and a high pressure regulator. During normal operation of the engine, the on-off valve provided in the first return passage is opened. Therefore, the fuel pressure is regulated by the low pressure regulator with the lower set pressure to generate sufficient fuel pressure necessary for normal operation of the engine. Can be done. In addition, when the engine is restarted at a high temperature, the on-off valve provided in the first return passage is closed, so that the fuel is regulated by the high-pressure pressure regulator with the higher set pressure, and the fuel vapor in the feed passage is injected from the injector with the high-pressure fuel. It is possible to prevent the startability from being deteriorated due to the eviction and the vapor lock. Moreover, since the first and second return passages do not return fuel from near the injector, but return fuel from the middle of the feed passage, they are arranged inside the fuel tank or near the fuel tank to save space. In addition to savings, it is possible to prevent the fuel temperature in the fuel tank from rising due to the high-temperature return fuel.

According to the second aspect of the present invention,
The feed passage and the inside of the fuel tank are connected by a first return passage provided with a low-pressure pressure regulator and a second return passage provided with a high-pressure pressure regulator. During normal operation of the engine, the first return passage is connected by a flow passage switching valve to the feed passage. Therefore, the fuel pressure is regulated by the low-pressure pressure regulator having the lower set pressure, so that a sufficient fuel pressure necessary for normal operation of the engine can be generated. When the engine is restarted at a high temperature, the flow path switching valve connects the second return passage to the feed passage. Therefore, the fuel is regulated by the higher pressure regulator having the higher set pressure, and the fuel vapor in the feed passage is increased by the high pressure fuel. It is possible to prevent the startability from being deteriorated due to the vapor lock, which is expelled from the injector. Moreover, since the first and second return passages do not return fuel from near the injector, but return fuel from the middle of the feed passage, they are arranged inside the fuel tank or near the fuel tank to save space. In addition to savings, it is possible to prevent the fuel temperature in the fuel tank from rising due to the high-temperature return fuel.

According to the third aspect of the present invention,
A variable pressure regulator is provided in the return passage that connects the feed passage and the inside of the fuel tank.When the engine is running normally, the set pressure of the variable pressure regulator is lowered to increase the fuel pressure necessary for normal operation. Can be generated. Further, when the engine is restarted at a high temperature, by increasing the set pressure of the variable pressure regulator, the fuel vapor in the feed passage is expelled from the injector by the high-pressure fuel, so that the startability due to the vapor lock can be prevented. Moreover, since the return passage does not return fuel from near the injector, but returns fuel from the middle of the feed passage, they can be arranged inside the fuel tank or near the fuel tank to save space. Instead, it is possible to prevent the fuel temperature in the fuel tank from rising due to the high-temperature return fuel.

According to the fourth aspect of the present invention,
If the solenoid valve is opened during normal operation of the engine, the set pressure of the variable pressure regulator becomes equal to the first valve opening pressure of the pressure regulator because the check valve does not function. When the solenoid valve is closed when the engine is restarted at a high temperature, the check valve provided in the bypass passage functions. Therefore, the set pressure of the variable pressure regulator is set to the first valve opening pressure of the pressure regulator and the second valve of the check valve. It becomes an added value with the valve opening pressure, and can be higher than the set pressure during the normal operation.

[Brief description of the drawings]

FIG. 1 is a diagram showing a fuel supply device for an engine according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a fuel supply device for an engine according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a fuel supply device for an engine according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a variable pressure regulator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 13 Injector 16 Fuel pump 17 Feed passage 19 1st return passage 20 2nd return passage 21L Low pressure regulator 21R High pressure regulator 21V Variable pressure regulator 22 On-off valve 23 Flow path switching valve 24 Return passage 25 Pressure regulator 26 Solenoid valve 27 Check Valve 33 Bypass passage E Engine P1 First valve opening pressure P2 Second valve opening pressure T Fuel tank

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F02M 69/00 340 F02M 69/00 340T

Claims (4)

[Claims] 1. An engine fuel supply system which pressurizes fuel in a fuel tank (T) with a fuel pump (16) and supplies the pressurized fuel to an injector (13) of an engine (E) connected downstream of a feed passage (17). In the device, the feed passage (17) and the inside of the fuel tank (T) are
A first return passage (19) provided with a low-pressure pressure regulator (21L) and a high-pressure pressure regulator (2
1H) is connected in parallel with the second return passage (20) provided with an on-off valve (22) in the first return passage (19) between the feed passage (17) and the low-pressure pressure regulator (21L). A fuel supply device for an engine, comprising: 2. An engine fuel supply system, wherein fuel in a fuel tank (T) is pressurized by a fuel pump (16) and supplied to an injector (13) of the engine (E) connected downstream of a feed passage (17). In the device, the feed passage (17) and the inside of the fuel tank (T) are
A first return passage (19) provided with a low-pressure pressure regulator (21L) and a high-pressure pressure regulator (2
1H) is connected in parallel with the second return passage (20) provided with the feed passage (1) through the passage switching valve (23).
7. A fuel supply device for an engine, wherein the fuel supply device selectively communicates the first return passage with the first return passage or the second return passage. 3. A fuel supply for an engine, wherein the fuel in a fuel tank (T) is pressurized by a fuel pump (16) and supplied to an injector (13) of the engine (E) connected downstream of the feed passage (17). A fuel supply device for an engine, wherein a variable pressure regulator (21V) is provided in a return passage (24) connecting a feed passage (17) and the inside of a fuel tank (T). 4. The variable pressure regulator (21V) provided in the return passage (24) includes a pressure regulator (25) having a first valve opening pressure (P1), and an upstream side of the pressure regulator (25). A solenoid valve (26) that opens and closes a return passage (24), a bypass passage (33) that bypasses the solenoid valve (26) and continues to a pressure regulator (25), and a second passage provided in the bypass passage (33). Valve opening pressure (P
The fuel supply device for an engine according to claim 3, further comprising: a check valve (27) having 2).