JPH08200176A - Fuel feeding device for internal combustion engine - Google Patents

Abstract

PURPOSE: To reduce a vapor amount in a delivery pipe during high temperature restarting by a method wherein a fuel piping is arranged in such a manner to be gradually elevated from the inlet part of the delivery pipe toward the top part of a bent part. CONSTITUTION: A fuel piping 18 forms a returnless pipe which ends with a delivery pipe 19. A bent part 25 is formed at a fuel piping 18 connected to an inlet part 24 arranged at the side wall part of the delivery pipe 19, the bent part 25 is formed in a position higher than that of the inlet part 24 of the delivery pipe 19, and the fuel piping 18 is arranged in such a manner to gradually heighten from the inlet part 24 of the delivery pipe 19 toward the bent part 25. When an engine temperature is high, vapor generated in fuel in the delivery pipe 19 gathers at the inner upper part of the delivery pipe 19. When a vapor amount is increased and the vapor fronts on the inlet part 24, the vapor flows out to the fuel piping 18 side through the inlet part 24 owing to buoyancy, and is raised and gathers at the top part of the bent part 25. Thus, vapor remaining in the delivery pipe 19 remains up to the upper surface height B of the inner wall of the inlet part 24 and is in a small quantity.

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 internal combustion engine which employs a returnless piping structure in which the fuel piping is terminated by a delivery pipe for distributing fuel to the injector.

[0002]

2. Description of the Related Art If the engine is stopped immediately after high-load running (uphill running, high-speed running), the temperature of the fuel in the delivery pipe becomes considerably high, and vapor easily occurs in the fuel. If the engine is restarted with a large amount of vapor accumulated in the delivery pipe, the vapor will be sucked into the injector and the engine startability will deteriorate, and idle rotation after restart will become unstable. Occurs. In recent years, in order to simplify and reduce the cost of fuel piping, the return piping that returns a portion of the fuel from the delivery pipe to the fuel tank side has been omitted, and a returnless piping configuration where the fuel piping ends at the delivery pipe has been adopted. There is something I did.

[0003]

In the fuel piping structure provided with the return piping, the actual construction of Sho 62-137379 is used.
As shown in the publication, the vapor in the delivery pipe can be discharged to the return pipe side, but in the returnless piping configuration, since there is no return pipe that discharges the vapor from the delivery pipe, the vapor stays in the delivery pipe. Resulting in. Therefore, as described above, the vapor in the delivery pipe is sucked into the injector at the time of high temperature restart, the engine startability is deteriorated, and the idle rotation after the restart becomes unstable.

The present invention has been made in consideration of such circumstances, and therefore an object thereof is to adopt a returnless piping structure, which can reduce the amount of vapor in the delivery pipe, and can increase the temperature. An object of the present invention is to provide a fuel supply device for an internal combustion engine, which can improve startability at the time of restart and stability of idle rotation.

[0005]

To achieve the above object, in a fuel supply system for an internal combustion engine according to claim 1 of the present invention, a returnless pipe whose fuel pipe is terminated by a delivery pipe for distributing fuel to an injector. In the configuration, a bent portion is formed in at least one location of the fuel pipe, the bent portion is arranged at a position higher than the inlet portion of the delivery pipe, and the fuel pipe is placed at the inlet of the delivery pipe. The pipe is arranged so as to gradually increase from the portion to the bent portion.

In this structure, as in claim 2, an expansion pipe part having an enlarged inner diameter may be provided in the middle of the fuel pipe downstream of the bent part. Alternatively, as in claim 3, a fuel filter may be provided in the middle of the fuel pipe on the downstream side of the bent portion, and the filter case of this fuel filter may function as the expansion pipe portion.

Further, as in claim 4, the inlet portion may be formed upward on the upper wall portion of the delivery pipe.
Further, as in claim 5, the expansion pipe portion may be arranged outside the engine room or in the vicinity of a partition wall of the engine room.

[0008]

[Operation] Vapor generated in the fuel in the delivery pipe is smaller in specific gravity than the fuel (liquid), and therefore accumulates in the upper portion of the delivery pipe. However, the amount of vapor increases and the vapor faces the inlet portion of the delivery pipe. Then, due to buoyancy, the fuel will come out from the inlet into the fuel pipe.

According to the structure of the first aspect, the bent portion formed at least at one position of the fuel pipe is located at a position higher than the inlet portion of the delivery pipe, and the fuel pipe extends from the inlet portion of the delivery pipe. Since the pipe is arranged so as to gradually rise to the top of the bent portion, the vapor that has come out of the inlet portion of the delivery pipe smoothly flows to the bent portion along the fuel pipe due to buoyancy. As a result, less vapor accumulates in the delivery pipe.

Further, in the second aspect, the vapor is stored in the enlarged pipe portion provided in the middle of the fuel pipe on the downstream side of the bent portion. As a result, the amount of vapor that can be stored on the fuel pipe side can be increased.

Further, in claim 3, a fuel filter is provided in the middle of the fuel pipe on the downstream side of the bent portion. In this fuel filter, a filter element is housed in a filter case, and the fuel is passed through the filter case to remove dust and the like in the fuel by the filter element.
Since the inner diameter of the filter case is larger than the fuel pipe,
This filter case can be made to function as an expansion tube portion that stores vapor.

On the other hand, since the inlet portion is formed upward on the upper wall portion of the delivery pipe, the vapor generated in the fuel in the delivery pipe is buoyant and the upper wall portion of the delivery pipe is buoyant. When it ascends to, there is an inlet (the connection port for the fuel pipe) there, and the vapor immediately escapes into the fuel pipe.

Further, according to the present invention, since the expansion pipe portion for storing the vapor is arranged outside the engine room or in the vicinity of the partition wall of the engine room and kept away from the engine, the expansion pipe portion receives less heat from the engine. As a result, the fuel temperature inside the expansion pipe becomes much lower than that inside the delivery pipe. Therefore, the vapor coming out of the inlet portion of the delivery pipe gradually radiates heat in the process of flowing into the expansion pipe portion in the fuel pipe, and while partly liquefied while flowing into the expansion pipe portion while lowering the temperature, in the expansion pipe portion. The vapor radiates heat and the temperature drops, liquefying.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. First, a schematic configuration of the entire fuel supply system will be described based on FIG. A fuel tank 12 is provided at a rear portion of the vehicle 11, a fuel pump 13 is provided in the fuel tank 12, and a filter 14 is attached to a suction port of the fuel pump 13. A pressure regulating valve 15 for maintaining a constant fuel pressure is provided on the discharge port side of the fuel pump 13, and excess fuel of the fuel discharged from the fuel pump 13 is returned into the fuel tank 12 through a return pipe 16. . The pressure regulating valve 15 and the return pipe 16 are connected to the fuel pump 13
It is also provided in the fuel tank 12.

The fuel discharged from the fuel pump 13 through the pressure regulating valve 15 is sent to the delivery pipe 19 through the fuel pipes 17 and 18. In the middle of the fuel pipe 17,
A fuel filter 20 that removes dust and the like in the fuel is provided. The delivery pipe 19 is horizontally installed near the intake manifold (not shown) of the engine 22 in the engine room 21 provided in the front part of the vehicle 11 (see FIG. 3).
The fuel in the delivery pipe 19 is distributed to the injector 23 provided for each cylinder of the engine 22 (internal combustion engine). In this case, the fuel pipes 17 and 18 have a returnless pipe structure that terminates at the delivery pipe 19, and therefore, no return pipe for returning the fuel from the delivery pipe 19 to the fuel tank 12 is provided.

As shown in FIG. 1, the downstream fuel pipe 18 connected to the inlet portion 24 provided in the side wall portion of the delivery pipe 19 is composed of, for example, a heat resistant rubber hose. A bent portion 25 is formed on the fuel pipe 18 so as to be convex upward, and the bent portion 25 is arranged at a position higher than the inlet portion 24 of the delivery pipe 19, and the lower surface of the inner wall of the top of the bent portion 25 is arranged. Is greater than or equal to the height B of the upper surface of the inner wall of the inlet portion 24, and the fuel pipe 18 is arranged so as to gradually increase from the inlet portion 24 of the delivery pipe 19 to the bent portion 25. Further, in this embodiment, the bent portion 25 is arranged near the partition wall 26 of the engine room 21 so as to be separated from the engine 22.

By the way, high load traveling (uphill, high speed traveling)
When the engine 22 is stopped immediately after that, the temperature of the engine 22 becomes high, and due to the heat radiation, the fuel temperature in the injector 23 and the delivery pipe 19 rises to the vapor generation temperature as shown in FIG. Generates vapor. Since this vapor has a smaller specific gravity than the fuel (liquid), it floats above the delivery pipe 19 and the inlet 24
Up to the height B of the inner wall upper surface of the inner wall of the delivery pipe 19, but when the amount of vapor further increases and the vapor faces the inlet portion 24, the vapor comes out of the inlet portion 24 into the fuel pipe 18 due to buoyancy. The bent portion 25 formed in the fuel pipe 18 is arranged at a position higher than the inlet portion 24 of the delivery pipe 19, so that the fuel pipe 18 is delivered to the delivery pipe 1.
Since it is arranged so that it gradually increases from the inlet portion 24 of the pipe 9 to the bent portion 25, the vapor that has come out of the fuel pipe 18 from the inlet portion 24 of the delivery pipe 19 travels through the fuel pipe 18 due to buoyancy and is bent 25. Flows to the side and collects at the top of the bent portion 25. Therefore, the vapor remaining in the delivery pipe 19 is up to the height B of the upper surface of the inner wall of the inlet portion 24. For this reason, even in the case of high temperature restart, the amount of vapor remaining in the delivery pipe 19 is small, and the startability during high temperature restart and idle rotation stability are improved.

Further, in this embodiment, since the bent portion 25 of the fuel pipe 18 is arranged near the partition wall 26 of the engine room 21 and is kept away from the engine 22, the bent portion 25 receives less heat from the engine 22. Becomes bent 25
The fuel temperature inside becomes much lower than that inside the delivery pipe 19. Therefore, the vapor coming out of the inlet portion 24 of the delivery pipe 19 gradually radiates heat in the process of flowing to the bent portion 25 in the fuel pipe 18 and partially stays at the top of the bent portion 25 while liquefying while lowering the temperature, Further, the vapor dissipates heat in the bent portion 25 to lower the temperature and liquefy. Engine 22
During such operation of the vapor, such a movement of the vapor is repeated, and during that time, the engine 22 and the delivery pipe 19 are gradually cooled by the cooling function of the traveling wind and the radiator (not shown), and the fuel inside the delivery pipe 19 is gradually cooled. The temperature drops to a temperature at which no vapor is generated.

In the first embodiment described above, the fuel pipe 1
Although the bent portion 25 of No. 8 is arranged near the partition wall 26 of the engine room 21, the point is that even in the engine room 21, it is at a position apart from the engine 22 to some extent (that is, a position where heat radiation received from the engine 22 is small). Needless to say, they may be arranged, and of course, they may be arranged outside the engine room 21.

On the other hand, in the second embodiment of the present invention shown in FIGS. 5 and 6, an enlarged pipe portion 31 having an enlarged inner diameter is provided in the middle of the fuel pipe 18 on the downstream side of the bent portion 25. The fuel pipe 18 on the downstream side of 31 is arranged so as to gradually rise from the inlet portion 24 of the delivery pipe 19 to the enlarged pipe portion 31. Further, the bent portion 25 and the enlarged pipe portion 31 are arranged outside the engine room 21, and the middle portion of the fuel pipe 18 is inserted into and supported by the partition wall 26 of the engine room 21 via the bush 27. The other structure is the same as that of the first embodiment.

In the second embodiment, the delivery pipe 19
When the vapor exiting from the inlet portion 24 of the fuel cell rises along the fuel pipe 18, it eventually reaches the expansion pipe portion 31, and the vapor is stored in the expansion pipe portion 31. The expansion pipe portion 31 serves to increase the amount of vapor that can be stored on the fuel pipe 18 side. Moreover, the expansion pipe portion 31 is connected to the engine room 21.
Since the heat radiation from the engine 22 is extremely small, the vapor is quickly radiated and liquefied in the expansion pipe portion 31.

It should be noted that the expansion pipe section 31 is provided in the engine room 21.
It may be arranged in the vicinity of the partition wall 26 inside, and in short, it may be arranged in the engine room 21 at a position apart from the engine 22 to some extent (that is, a position where heat radiation received from the engine 22 is small).

On the other hand, FIG. 7 shows a third embodiment of the present invention.
The position of the inlet portion 32 of the delivery pipe 19 is different from that in each of the above embodiments. That is, in the third embodiment, the delivery pipe 19
The inlet portion 32 is formed upward on the upper wall portion of the
The fuel pipe 18 is connected to 2. Other configurations are
This is the same as the second embodiment.

In the third embodiment, the delivery pipe 19
When the vapor generated in the fuel inside reaches the upper wall portion of the delivery pipe 19 by buoyancy, the vapor immediately comes out into the fuel pipe 19 from the inlet portion 32 formed in the upper wall portion. As a result, the dischargeability of vapor from the delivery pipe 19 to the fuel pipe 18 is further improved, and the amount of vapor retained in the delivery pipe 19 is extremely reduced.

In each of the first to third embodiments described above, the fuel filter 20 is provided in the fuel pipe 17 upstream of the bent portion 25. However, in the fourth embodiment of the present invention shown in FIG. A fuel filter 20 is provided in the middle of the fuel pipe 18 on the downstream side of the bent portion 25, instead of the enlarged pipe portion 31. In this fuel filter 20, a filter element 34 is housed in a filter case 33, and the fuel is passed through the filter case 33 to remove dust and the like in the fuel by the filter element 34. The inner diameter of the filter case 33 is a fuel pipe. Since the filter case 33 is larger than 18, the filter case 33 can function as an expansion tube portion that stores vapor. Therefore, in this fourth embodiment, the vapor coming out from the inlet portion 24 of the delivery pipe 19 is the fuel pipe 1
8 rises and is stored in the filter case 33, where heat is radiated and liquefied.

In the fourth embodiment, it is sufficient to change the position of the fuel filter 20 to the downstream side of the bent portion 25.
There is an advantage that the expansion tube portion 31 is unnecessary and the cost can be reduced accordingly. In the configuration of FIG. 7 (the configuration in which the inlet portion 32 is formed upward on the upper wall portion of the delivery pipe 19),
It goes without saying that the fuel filter 20 may be provided in place of the expansion pipe portion 31.

Also in these cases, the fuel filter 2
The position of 0 is not limited to the outside of the engine room 21, and the fuel filter 20 may be arranged near the partition wall 26 in the engine room 21. It may be arranged at a distant position (that is, a position where heat radiation received from the engine 22 is small).

In each of the above embodiments, as shown in FIG. 2, the pressure regulating valve 15 and the return pipe 16 are provided in the fuel tank 12, but the pressure regulating valve 15 and the return pipe 16 are omitted, and the fuel pipe 1
The fuel pressure in 8 may be detected by the fuel pressure sensor, and the voltage applied to the motor of the fuel pump 13 may be feedback-controlled in accordance with the detected value to make the fuel pressure constant. Other,
The present invention can be implemented with various modifications within a range not departing from the spirit of the present invention, such as forming bent portions at two or more locations of the fuel pipe 18.

[0029]

As is apparent from the above description, according to the first aspect of the present invention, the bent portion formed at least at one position of the fuel pipe is located at a position higher than the inlet portion of the delivery pipe. Since the fuel pipe is arranged so that the fuel pipe is gradually raised from the inlet of the delivery pipe to the top of the bent portion, the vapor that has come out of the inlet of the delivery pipe is smoothly moved to the bent portion of the fuel pipe by buoyancy. Therefore, the amount of vapor accumulated in the delivery pipe can be reduced, and the startability at high temperature restart and the idle rotation stability can be improved.

Further, according to the second aspect, since the expansion pipe portion is provided in the middle of the fuel pipe on the downstream side of the bent portion, by accumulating the vapor in the expansion pipe portion, the amount of vapor that can be stored on the fuel pipe side is increased. Can be increased.

Further, according to the third aspect, since the fuel filter is provided in the middle of the fuel pipe on the downstream side of the bent portion, the filter case of this fuel filter can be made to function as an expansion pipe portion for accumulating vapor. It is possible to achieve both an increase in vapor storage amount on the fuel pipe side and a cost reduction.

On the other hand, in the present invention, since the inlet portion is formed upward on the upper wall portion of the delivery pipe, the vapor floating on the upper wall portion in the delivery pipe is immediately fed to the fuel pipe from the inlet portion of the upper wall portion. The vapor discharge property can be further improved.

Further, according to the present invention, since the expansion pipe part for accumulating the vapor is arranged outside the engine room or in the vicinity of the partition wall of the engine room to lower the temperature of the expansion pipe part, the expansion pipe part is stored in the expansion pipe part. The heat dissipation of the vapor thus obtained can be enhanced, and the liquefaction of the vapor can be promoted.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of a fuel piping system showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of the entire fuel supply system of the first embodiment.

FIG. 3 is a diagram showing a mounting relationship between a delivery pipe and an injector.

FIG. 4 is a diagram showing the fuel temperature of each part at the time of high temperature restart.

FIG. 5 is a vertical cross-sectional view of the main part of the fuel piping system showing the second embodiment of the present invention.

FIG. 6 is a diagram showing a schematic configuration of the entire fuel supply system of a second embodiment.

FIG. 7 is a vertical cross-sectional view of the main part of the fuel piping system showing the third embodiment of the present invention.

FIG. 8 is a vertical cross-sectional view of a main part of a fuel piping system showing a fourth embodiment of the present invention.

[Explanation of symbols]

11 ... Vehicle, 12 ... Fuel tank, 13 ... Fuel pump, 1
5 ... Filter, 16 ... Return pipe, 17, 18 ... Fuel pipe,
19 ... Delivery pipe, 20 ... Fuel filter, 21 ... Engine room, 22 ... Engine (internal combustion engine), 23 ... Injector, 24 ... Inlet part, 25 ... Bend part, 26 ... Partition wall, 31 ... Expansion pipe part, 32 ... Inlet part, 33 ... Filter case, 34 ... Filter element.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F02M 55/02 310 C 69/00

Claims (5)

[Claims] 1. A fuel supply device for an internal combustion engine having a returnless pipe structure in which a fuel pipe terminates at a delivery pipe for distributing fuel to an injector, wherein a bent portion is formed in at least one portion of the fuel pipe. A fuel supply for an internal combustion engine, wherein a bent portion is arranged at a position higher than an inlet portion of the delivery pipe, and the fuel pipe is arranged so as to be gradually raised from the inlet portion of the delivery pipe to the bent portion. apparatus. 2. The fuel supply device for an internal combustion engine according to claim 1, wherein an enlarged pipe portion having an enlarged inner diameter is provided in the middle of the fuel pipe on the downstream side of the bent portion. 3. The internal combustion engine according to claim 2, wherein a fuel filter is provided in the middle of the fuel pipe on the downstream side of the bent portion, and the filter case of the fuel filter functions as the expansion pipe portion. Fuel supply device. 4. The fuel supply device for an internal combustion engine according to claim 1, wherein the inlet portion is formed upward on an upper wall portion of the delivery pipe. 5. The fuel supply system for an internal combustion engine according to claim 2, wherein the expansion pipe portion is arranged outside the engine room or near a partition wall in the engine room.