JPH076463B2 - Vapor cooling device in fuel tank - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vapor cooling device in a fuel tank, which prevents harmful effects caused by a large amount of vapor in the fuel tank.

[Conventional technology]

Generally, the fuel injection device is configured as shown in FIG.

In the figure, reference numeral 1 denotes a vehicle engine, which is composed of a cylinder 1A, a piston 1B, a combustion chamber 1C and the like. The engine 1 is provided with a fuel injection valve 2 which is attached to a tip end side of each branch pipe 3B described later and injects fuel into the combustion chamber 1C, and sucks outside air into the combustion chamber 1C. An intake manifold 3 is provided, and a throttle valve 4 is provided upstream of the collector 3A of the intake manifold 3.

Reference numeral 5 denotes a fuel tank for containing the fuel A. The fuel tank 5 is formed in a saddle shape including a main tank portion 5A and a sub tank portion 5B, and a bottom shaped portion 5C straddles the rear axle housing 6 to form the main tank portion 5A. The sub tank portion 5B and the sub tank portion 5B are arranged on the left and right.

Reference numeral 7 denotes a fuel pump which is located inside the fuel tank 5 and is located on the main tank portion 5A side, and which pumps the fuel A to the fuel injection valve 2. Reference numeral 8 is a supply pipe in which one end side is connected to the fuel pump 7 and a fuel filter 9 is interposed in the middle, and a pressure regulator 10 is connected to the other end side of the supply pipe 8. A plurality of fuel injection valves 2 are connected between the fuel filter 9 and the pressure regulator 10 in the supply pipe 8 in correspondence with the number of cylinders of the engine. The pressure regulator 10 is provided with a control pressure introducing pipe for introducing a difference in negative pressure generated in the collector 3A of the intake manifold 3 as a control pressure by opening / closing the throttle valve 4.
11 is connected. Then, by introducing a control pressure into the pressure regulator 10 via the introduction pipe 11, the fuel pressure (fuel pressure) supplied to each fuel injection valve 2 is controlled to a predetermined set pressure according to the operating condition of the engine 1. It has become.

Reference numeral 12 is a return pipe for returning the surplus oil of the fuel A supplied from the fuel pump 7 to the fuel tank 5 side. One end side of the return pipe 12 is connected to the pressure regulator 10 and the other end side is connected to the fuel tank 5 side. It extends to the main tank part 5A side.

Reference numeral 13 is provided on the tip side of the return pipe 12 located on the main tank portion 5A side in order to suck the fuel A stored in the sub tank portion 5B of the fuel tank 5 and cause it to flow to the main tank portion 5A side. In the fuel suction pump as an ejector, the base end side of the suction pipe 14 is connected to the fuel suction pump 13, and the suction port (filter) of the front end side 14A of the suction pipe 14 is provided at the bottom of the sub tank portion 5B. Has been done.

Reference numeral 15 is a canister having a built-in activated carbon or the like that temporarily absorbs vapor generated by vaporization of the fuel A.
The inflow side of 15 is connected to the inside of the fuel tank 5 via an inflow pipe 16 and a check valve 17 provided in the inflow pipe 16. Also, the canister 15 has a purge control valve 15A
The purge control valve 15A is provided with a back pressure introducing pipe 18 for guiding the pressure in the vicinity of the throttle valve 4 among the pressure in the intake manifold 3 as a back pressure, and a vapor stored in the canister 15 in the intake manifold 3. A discharge pipe 19 for purging (discharging) into the collector 3A is connected at a position downstream of the valve 4, respectively. Then, the canister 15 allows the vapor generated in the fuel tank 5 to flow in through the inflow pipe 16 and stores it in activated carbon or the like inside, while the purge control valve 15A is an off-idle valve in which the throttle valve 4 starts opening. The negative pressure fluctuation that sometimes occurs in the intake manifold 3 is opened by introducing it through the back pressure introducing pipe 18, and the vapor stored in the canister 15 is purged from the discharge pipe 19 into the intake manifold 3 as purge air. It is designed to be activated as a part of fuel.

The fuel injection device according to the prior art has the above-mentioned configuration, and its operation will be described below.

First, the fuel pump 7 is rotated by the starting operation of the engine 1, the fuel A in the fuel tank 5 is ejected into the supply pipe 8, and the fuel injection valve is injected based on the injection pulse signal of the control unit (not shown). It is injected from 2 to the combustion chamber 1C side. At this time, the fuel A in the supply pipe 8 is adjusted in fuel pressure by the pressure regulator 10, and surplus oil is sequentially returned in the return pipe.
It is returned to the inside of the fuel tank 5 via 12. Then, the fuel A injected from the fuel injection valve 2 is sucked into the combustion chamber 1C while being mixed with the intake air drawn into the intake manifold 3 as the piston 1B reciprocates, and becomes exhaust gas after combustion. Exhaust manifold (not shown)
Exhausted from.

On the other hand, the excess return oil that flows back through the return pipe 12 passes through the fuel suction pump 13 and the main tank portion 5A.
And the fuel suction pump 13 is
Aspirate fuel A in 5B.

[Problems to be Solved by the Invention]

By the way, in the above-described conventional technique, for example, when the vehicle repeatedly starts and stops, such as during a traffic jam, or when the temperature in summer is high, the temperature in the engine room becomes high,
The temperature of the return oil in the return pipe 12 which flows back into the fuel tank 5 through the inside of the engine room is also overheated and returned to a high temperature. For this reason, vapor is likely to be generated in the return pipe 12 whose pressure is lower than that of the supply pipe 8, and the temperature of the fuel A in the fuel tank 5 is also increased, so that the fuel A is easily vaporized. Then, when vapor is generated in the return pipe 12 and the return oil mixed with the vapor is jetted from the fuel suction pump 13 into the fuel tank 5, the vapor of the return oil is filled in the fuel tank 5.

Further, when the fuel liquid level in the fuel tank 5 is low, the return oil ejected from the fuel suction pump 13 hits the liquid level of the fuel A, which is easily vaporized, and a large amount of vapor is generated, so that the fuel tank 5 Will be full. Then, the vapor filled in the fuel tank 5 is passed through the inflow pipe 16 to the canister 15
It is stored inside.

However, when the amount of vapor generated exceeds the limit of the capacity of the canister 15, the amount exceeding the limit is released from the canister 15 into the atmosphere, which not only wastes fuel,
There is a problem that it may cause air pollution and an offensive odor.

Further, when vapor is generated in the return pipe 12, there is a problem that when the return oil mixed with the vapor passes through the fuel suction pump 13, an abnormal noise of “juju” is generated.

The present invention has been made in view of the above-mentioned problems of the prior art, and can suppress the generation of vapor in the fuel tank to a low level to reliably prevent the vapor from being released into the atmosphere and reduce the generation of abnormal noise. An object of the present invention is to provide a vapor cooling device in a fuel tank that can be used.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the configuration adopted by the present invention is a fuel tank composed of a main tank portion and a sub tank portion, and is located on the main tank portion side in the fuel tank. A fuel suction pump for sucking the fuel in the sub-tank part, a vapor collection case for covering the fuel suction pump and collecting vapor generated by the return oil from the return pipe, and for forcedly ventilating the air in the cab. A ventilation device with a built-in fan whose duct extends outside the operator's cab, a first conduit connected to a vapor recovery case in the fuel tank, and leading out the vapor recovered in the vapor recovery case to the outside of the fuel tank, and the ventilation. One end of the device is connected to the first conduit provided in the duct, and the vapor from the first conduit is removed by an air flow passing through the duct. A vapor cooler for cooling; and a second conduit connecting between the other end of the cooler and the fuel tank and returning the fuel liquefied in the cooler into the fuel tank. The case is attached to the bottom side of the main tank section and has a communication hole at the lower end side for communicating the inside and outside of the vapor recovery case.

[Action]

With the above configuration, even when the return oil from the return pipe reaches the fuel tank and a large amount of vapor is generated in the vicinity of the fuel suction pump, while collecting this vapor in the vapor recovery case, it is passed through the first conduit. Can be led to a vapor cooler outside the fuel tank, the vapor can be cooled and liquefied in the vapor cooler, and the liquefied vapor (fuel) in the vapor cooler can be passed through the second conduit. It can be used as normal fuel by returning it to the fuel tank.

Further, since the vapor recovery case is attached to the bottom side of the main tank part and the lower end side thereof is provided with a communication hole for communicating the inside and outside of the vapor recovery case, the sub tank sucked by the fuel suction pump together with the return oil from the return pipe. The fuel inside the tank can be circulated from the inside of the vapor collection case to the main tank side through the communication hole on the lower end side, and the fuel at this time strikes the liquid surface of the fuel on the main tank side or makes an abnormal noise. As a result, it is possible to reliably suppress the extra generation of vapor from the fuel in the fuel tank.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In this embodiment, the same components as those of the prior art shown in FIG. 3 described above are designated by the same reference numerals and the description thereof will be omitted.

In the figure, reference numeral 21 denotes a vapor recovery case provided on the main tank portion 5A side of the fuel tank 5. The vapor recovery case 21 is formed in a cylindrical shape with a lid and is attached to the bottom side of the main tank portion 5A. The vapor recovery case 21 covers the fuel suction pump 13 from the upper side, and the upper end side of the vapor recovery case 21 has a first
Conduit 31 of is connected. Also, the vapor collection case
A communication hole 22 that communicates the inside and outside of the vapor recovery case 21 is provided on the lower end side of the 21. In addition, a vapor collection case
An air vent hole 23 is provided at the upper end of 21 when the liquid level suddenly rises due to refueling. This air vent hole 23
The vapor accumulated in the case 21 is formed so small that it cannot easily escape.

Reference numeral 24 denotes a ventilation duct extending from the rear (not shown) of the driver's cab of the vehicle to the outside of the driver's cab. One end of the duct 24 is connected to an air purifier 25 as a ventilation device. The air is discharged to the outside of the cab through the opening 24A on the other end side. Here, the air purifier 25 is disposed in the cab on the rear side of the rear seat and has an electric fan (not shown) inside thereof.
Is built in. Then, the air purifier 25 forcibly sucks the air in the driver's cab (for example, cooled down to 25 ° C. or less by an air conditioner) by the rotation of the fan to the suction ports 25A, 25
The air is sucked from A, and the dust and the like in the air are removed by the filters 25B and 25B of the suction ports 25A. In addition, a substantially cylindrical expansion portion 24B for accommodating a vapor cooler 26 described later is formed in the middle of the duct 24.

Reference numeral 26 denotes a vapor cooler arranged in the expanded portion 24B of the duct 24, and the air flow in the duct 24 is the cooler 26 in the expanded portion 24B.
It is designed to be distributed as cold air around the. The vapor cooler 26 is formed in a cylindrical shape with a bottom, and has a case 27 in which cooling fins 27A, 27A, ...
A lid 29 that covers the upper end opening of 27 and defines a cooling chamber 28 in the case 27, and is disposed in the cooling chamber 28 and is formed of continuous porous foamed natural rubber or sponge. And a filtering member 30. The lid 29 is provided with a vapor inlet 29A, and the case 27 is provided with an outlet 27B at the bottom. The inflow port 29A is connected to the other end side of the first conduit 31 described later so that the vapor generated in the fuel tank 5 is continuously introduced into the cooling chamber 28.

Reference numeral 31 denotes a first conduit whose one end is connected to the upper side of the vapor recovery case 21 in the fuel tank 5 and which leads out the vapor generated in the recovery case 21 to the outside.

Further, reference numeral 32 denotes a second conduit having one end connected to the outlet 27B of the cooler 26 and the other end extending into the fuel tank 5, and the second conduit 32 cools the vapor in the cooler 26. By doing so, the liquefied fuel is sequentially returned from the outlet 27B into the fuel tank 5. Here, the second conduit 32 is formed of a flexible hose or the like together with the first conduit 31, and is provided so as to extend to the vicinity of the bottom of the fuel tank 5.

The vapor cooling device in the fuel tank according to the present embodiment has the above-mentioned structure, and its operation will be described below. Since the overall operation of the fuel injection device is the same as that of the above-mentioned conventional technique, its explanation is omitted here.

When the fuel temperature of the return oil in the return pipe 12 rises when the vehicle is running in a traffic jam or when the temperature rises in the summer, and the fuel temperature of the fuel A in the fuel tank 5 rises as a result, the inside of the return pipe 12 increases. Therefore, vapor is easily generated and the fuel A in the fuel tank 5 is easily vaporized.

Then, when vapor is generated in the return pipe 12, the return oil mixed with the vapor flows out from the fuel suction pump 13 into the vapor recovery case 21 in the fuel tank 5 and fills the inside. On the other hand, when the liquid level of the fuel A in the fuel tank 5 is low, the return oil ejected from the fuel suction pump 13 hits the liquid level of the fuel A, the fuel temperature rises and the fuel A is easily vaporized.
Is vaporized in a large amount, and the vapor is filled in the vapor collection case 21.

Then, the vapor filled in the vapor recovery case 21 is sequentially drawn out of the fuel tank 5 via the conduit 31, and the cooler 26
Flows into the cooling chamber 28. Then, the vapor that has flowed into the cooling chamber 28 gradually passes through the small diameter passages 30A of the filtering member 30, is cooled by the air flow that flows through the expanded portion 24B of the dough 24, and is liquefied again as liquid fuel. Become second
Is returned to the fuel tank 5 from the conduit 32.

Here, in the driver's cab of the vehicle, an air conditioner is used when the temperature is high in summer or the like, and for example, since it is in a temperature state of 25 ° C. or less, the air flow circulating in the duct 24 by the air purifier 25 is also 25 ° C. or less. It becomes cold wind. Then, the cold air cools the vapor in the cooling chamber 28 together with the filtering member 30 while contacting the case 27 of the cooler 26. Further, since a large number of cooling fins 27A are provided in the case 27 so as to have a large heat exchange area, the cold air in the duct 24 effectively cools and liquefies the vapor in the cooling chamber 28, which is surely used as fuel. Can be played.

As described above, the portion of the fuel suction pump 13 in which the vapor is most likely to be generated is covered in the fuel tank 5, the vapor is collected before the fuel tank 5 is filled with the vapor, and liquefied by the vapor cooler 26. Therefore, the amount of vapor generated in the fuel tank 5 can be significantly reduced, the amount of vapor flowing into the canister 15 can be reduced, and a large amount of vapor can be discharged from the canister 15 as in the conventional technique. It is possible to prevent waste of A and generation of an offensive odor, solve problems such as air pollution, and reliably improve fuel consumption even in a vehicle equipped with a large displacement engine.

Furthermore, since the fuel suction pump 13 that is the source of the abnormal noise is covered with the vapor recovery case 21, the abnormal noise from the fuel suction pump 13 can be suppressed to a low level and noise can be reduced. Further, since the vapor recovery case 21 is attached to the bottom side of the main tank portion 5A and the communication hole 22 for communicating the inside and outside of the vapor recovery case 21 is provided on the lower end side thereof, the fuel suction pump together with the return oil from the return pipe 12 is provided. The fuel in the sub-tank portion 5B sucked by 13 can be circulated from the inside of the vapor recovery case 21 to the main tank portion 5A side through the communication hole 22 on the lower end side. It is possible to effectively prevent hitting of the liquid surface of the fuel and the generation of abnormal noise, and it is possible to reliably suppress the extra generation of vapor from the fuel in the fuel tank 5.

If the case 27 of the vapor cooler 26 is made of a metal material having high thermal conductivity, the cooling fins 27A can effectively cool the inside of the cooling chamber 28.

Further, in the present embodiment, the second conduit 32 is extended to the sub tank portion 5B side, but it may be extended to the main tank portion 5A side.

〔The invention's effect〕

As described above in detail, according to the present invention, a vapor recovery case that covers the fuel suction pump provided in the fuel tank, a ventilation device with a fan in which the duct extends outside the operator's cab, and a duct in the ventilation device are provided. And a vapor cooler having an upstream side connected to the vapor recovery case via a first conduit and a downstream side connected to a fuel tank via a second conduit. Since the vapor is collected and liquefied at the portion of the fuel suction pump where vapor easily occurs, the vapor generated in the fuel tank can be significantly reduced. Further, due to the large amount of vapor generated, a large amount of vapor is not discharged into the atmosphere as in the prior art, so that it is possible to prevent waste of fuel and air pollution. Further, the fuel collection pump, which is the source of the abnormal noise, is attached to the bottom side of the main tank so as to cover the fuel collection pump with the vapor collection case, and the lower end side thereof is provided with a communication hole for communicating the inside and outside of the vapor collection case. Since it is provided, even if the fuel level on the main tank side is low, the noise generated from the fuel suction pump can be suppressed to a low level, and noise can be reduced, and the return from the return pipe can be reduced. The fuel in the sub-tank part sucked together with the oil by the fuel suction pump can be circulated from the inside of the vapor recovery case to the main tank part side through the communication hole on the lower end side. It is possible to effectively prevent the surface from being hit or the abnormal noise to be generated, and it is possible to reliably suppress the extra generation of vapor from the fuel in the fuel tank.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention, FIG. 1 is a longitudinal sectional view showing a vapor cooling device in a fuel tank, FIG. 2 is a perspective view showing an air purifier and a duct, and FIG. FIG. 1 is an overall configuration diagram of a fuel injection device according to a conventional technique. 5 ... Fuel tank, 5A ... Main tank part, 5B ... Sub tank part, 12 ... Return piping, 13 ... Fuel suction pump, 21 ... Vapor recovery case, 25 ... Air purifier, 26 ...
… Vapor cooler, 31 …… First conduit, 32 …… Second conduit.

Claims (1)

[Claims] 1. A fuel tank comprising a main tank portion and a sub tank portion, and a fuel suction pump which is located on the main tank portion side in the fuel tank and which sucks the fuel in the sub tank portion by return oil from a return pipe. , A vapor collection case that covers the fuel suction pump and collects vapor generated by the return oil from the return pipe, and a ventilation with a built-in fan in which a duct extends outside the cabin to forcibly ventilate the air in the cabin. A device, a first conduit connected to a vapor recovery case in the fuel tank, for leading out the vapor recovered in the vapor recovery case to the outside of the fuel tank, and a first conduit provided at a midway of the duct of the ventilation device. A vapor cooler connected to one conduit for cooling the vapor from the first conduit by an air stream flowing through the duct;
A second conduit that connects between the other end of the cooler and the fuel tank, and returns the fuel liquefied in the cooler into the fuel tank; and the vapor recovery case includes the main tank portion. A vapor cooling device in a fuel tank, which is attached to the bottom side of the fuel tank and has a communication hole at the lower end side for communicating the inside and outside of the vapor recovery case.