JP3300114B2 - Engine fuel supply system - Google Patents

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.

[0002]

2. Description of the Related Art In a space of a fuel tank containing gasoline or the like, which is a fuel for a vehicle engine, fuel vapor is generated due to a change in outside air temperature or atmospheric pressure. If the vaporized fuel is released into the atmosphere as it is, it will cause air pollution.Consequently, harmful components are absorbed and adsorbed by activated carbon or the like so that the vaporized fuel is guided to the canister device through a pipe line. From the atmosphere.

For example, according to Japanese Utility Model Laid-Open Publication No. 2-78755, an automatic opening / closing valve which is set to an open state at a predetermined pressure or higher is provided in the middle of a pipe communicating with a fuel tank, and a canister device provided upstream is provided. In addition, a configuration has been proposed in which vaporized fuel is guided to a canister device while upstream and downstream of a supercharger.

[0004] On the other hand, regulations on evaporative fuel are being tightened in connection with measures against air pollution, and a reduction in the amount of hydrocarbons released into the atmosphere during running and a reduction in the internal pressure of the fuel tank have been implemented. We are trying to cope with large size.

[0005]

However, there is the following problem in the case where the engine operating state and the stop state are both made compatible in order to cope with the regulation of the evaporated fuel described above. That is, in the operating state, there is a demand to reduce the ventilation resistance from the tank-canister device to the atmospheric opening of the canister device due to the stricter regulation of the internal pressure in the resin tank of the resin blow molding. Further, if the fuel vapor is directly introduced into the engine combustion chamber to purify the combustion (purge), the controllability of the air-fuel mixture ratio is impaired. Therefore, it is desirable to purify the fuel vapor by passing it through the canister as long as possible.

On the other hand, when the engine is stopped, it is desired that the evaporated fuel be passed through the canister device for a long time to be purified, and then released from the atmosphere opening. Further, in order to operate an automatic refueling stop device provided in a refueling gun for refueling the fuel tank, it is necessary to increase the internal pressure of the fuel tank to a certain value or more. Further, it is necessary to prevent the fuel in the liquid state from flowing into the canister device.

When the above conditions are summarized in a chart, it is necessary to set the canister device as shown in FIG. That is, conflicting conditions must be satisfied between the engine operating state and the stopped state.

Therefore, the evaporative fuel supply device for an engine according to the present invention has been made in view of the above problems,
It is an object of the present invention to satisfy both of the contradictory conditions of the engine operating state and the stopped state, and to cope with the strengthening of the regulation of the evaporated fuel and the reduction of the fuel tank internal pressure.

[0009]

According to the present invention, in order to solve the above-mentioned problems and achieve the object, a first method for guiding evaporated fuel generated inside a fuel tank to a canister device is provided.
An evaporative fuel supply device for an engine, comprising: a pipe, and a first valve provided in the middle of the first pipe and set to an open state when an internal pressure of the fuel tank does not satisfy a predetermined value. A second pipe that is provided in parallel with the first pipe to guide fuel to the canister apparatus; and a second pipe that is provided in the middle of the second pipe and that has a predetermined internal pressure during operation of the engine. A second valve that is set to an open state until the value exceeds a predetermined value when the value exceeds a predetermined value, and a first opening of the first conduit in the canister device includes:
A difference in the length of the fuel vapor passing through the canister is provided at a position farther from the atmospheric opening provided in the canister device than the second opening of the second conduit , and
Determining means for determining whether the gin is in an operating state;
The engine is not running based on the judgment result of the judgment means
At this time, only the first valve is opened and the engine is running.
Control to release both the first valve and the second valve.
It is characterized by controlling .

[0010]

With the above arrangement, the fuel vapor generated inside the fuel tank is guided to the canister device via the first valve which is set to the open state when the internal pressure of the fuel tank does not satisfy the predetermined value, while the engine is operating. When the internal pressure of the fuel tank exceeds a predetermined value, the liquid is guided to the canister device through a second valve which is set to an open state until the internal pressure becomes equal to or lower than the predetermined value. The canister device is disposed at a position farther from the atmospheric opening of the canister device than the second opening of the second conduit, and the purification of the evaporated fuel is sufficiently performed by passing through the canister, and the canister device is connected via the second valve. The fuel vapor introduced into the canister serves to be supplied to the engine after being purified by passing through the canister.

[0011]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. The same reference numerals indicate the same objects throughout the drawings. FIG. 1 is a schematic configuration diagram showing the configuration of the embodiment. In this figure, a fuel tank 1 is provided with a tank cap 2 which is attached and detached when fuel gasoline F is supplied, and a tip of a fuel gun 3 shown by a broken line in the figure is inserted into the tank. The fuel gun is provided with an auto stop 3a that operates to automatically stop the fuel supply when the fuel tank is full. Since the automatic stop detects the fuel supply pressure and operates when the pressure becomes higher than a predetermined pressure, it is necessary to maintain the internal pressure of the tank 1 at a predetermined value or more.

When the gasoline G in the tank 1 decreases, a space portion is generated upward. In this space portion, evaporative fuel V is generated due to a change in outside air temperature or the like. Also,
An internal pressure sensor 4 for detecting an internal pressure in the space is provided in the space, and is configured to output a pressure value to the control unit 100 as an electric signal after conversion.

A pipe 5 for guiding the evaporated fuel V to a separator 6 is provided in communication with the ceiling of the space of the tank 1. Further, a pipe 7 is piped from the separator 6 toward the branch portion 8, and is branched into a pipe 9 and a pipe 10. A first valve 11 is provided at an intermediate position of the pipe 9,
An electromagnetic valve, which opens in response to a drive signal from the control unit 100 and is normally kept closed, is provided. Instead of the first valve provided in this manner, a check valve 110 including a ball and a compression spring may be used.

On the other hand, the control unit 10
A second valve 12, which is an electromagnetic valve that opens in response to a drive signal from 0 and is normally kept closed, is provided.

The pipes 9 and 10 laid as described above are connected to the canister device 13. The canister device 13 is provided with a fuel vapor V introduced through pipes 9 and 10.
Harmful substances are adsorbed by the built-in activated carbon and released to the outside through the atmosphere opening 14 and the canister device 13
It is provided for introducing the evaporated fuel V partially purified into the engine combustion chamber through a pipe 15 to purify the combustion (purge).

Next, FIG. 2 is a sectional view of a main part of the canister device 13, showing a state in which openings 9a, 10a of the tubes 9, 10 are opened at different portions in the canister device 13. . In this figure, the canister device 1
3 is a container 22 and a partition 2 provided inside the container 22
0, 21 and activated carbon 18 filled therein. The pipe 9 is provided so as to open above the partition wall 20 as shown in the figure, while the pipe 10 is provided with the partition walls 20 and 21.
Is provided so as to be opened at an intermediate portion of the first portion.

Therefore, according to the above configuration, as shown in the operation explanatory view of FIG.
a, the distance L from the pipe 10 to the atmosphere opening 14 from 10a
1, L2 will be different as shown. Therefore, the evaporated fuel V discharged from the opening 9a of the pipe 9 passes through the activated carbon 18 while passing through a portion formed between the partition wall 20, the partition wall 21 and the inner wall of the container as shown in the figure, and passes through the atmosphere opening portion. 14 will be reached. Further, the evaporated fuel V discharged from the opening 10a reaches the pipe 15 at a distance L2.

The operation having the above configuration will be described with reference to the operation explanation flowchart of FIG. 4. When the purification of the evaporated fuel is started irrespective of the operation state of the vehicle, whether or not the tank 1 is closed, the operation proceeds to step S1. The internal pressure sensor 4 determines whether or not the internal pressure satisfies a predetermined value. If the internal pressure is not satisfied, the control unit 10 proceeds to step S2 to open the normally closed first valve 11.
0 controls.

When the check valve 110 is provided, the ball moves and opens due to the action of the internal pressure, and the evaporated fuel is transferred into the canister device 13 via the pipe 9 until the internal pressure satisfies a predetermined value. After being introduced and purified, it is released from the atmosphere opening 14 to the outside. Next, if the condition is satisfied in step S1, the process proceeds to step S3, and it is determined whether or not the engine is operating. If the engine is in operation, the process proceeds to step S4. In step S4,
The internal pressure sensor 4 again determines whether or not the internal pressure of the tank 1 satisfies a predetermined value. If the internal pressure sensor 4 does not satisfy the condition, the process proceeds to step S5, the second valve 12 is opened, and the fuel vapor is removed from the canister device. After being introduced into the pipe 13 through the pipe 10 and purified, the pipe 15 is sent to the engine combustion chamber.

If the condition is not satisfied in step S3 and if the condition is satisfied in step S4, the process returns (S6). Therefore, by performing the control as described above, it is possible to satisfy the conflicting conditions between the engine operating state and the stopped state of the canister device as shown in FIG.

FIG. 5 is a diagram showing an operation state of the second valve which opens and closes in response to a change in the internal pressure of the tank 1. As shown in FIG. 5, the second valve opens and closes in both positive and negative states of the internal pressure of the tank. I have. By controlling in this way, even when the tank internal pressure becomes a negative pressure state, the atmosphere can be introduced into the tank.As a result, a recent blow-molded fuel tank that is weak to the negative pressure can be used. Can also respond.

The invention of the present application described above is not limited to the configuration of each of the above embodiments, but can be set and changed as appropriate without departing from the spirit of the invention. For example, the fuel is not limited to gasoline. Any volatile fuel can be used.

[0023]

As described above, according to the present invention,
When the engine is stopped , the canister must be installed to satisfy both conflicting conditions of the engine running and the stopped state.
Harmful components of evaporative fuel released into the atmosphere via a storage device
The canister device when the engine is running.
Thus, it is possible to provide an evaporative fuel supply device for an engine capable of suppressing the excessive increase of the internal pressure of the engine and coping with the stricter regulation of the evaporative fuel and the reduction of the internal pressure of the fuel tank.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a configuration of an embodiment.

FIG. 2 is a sectional view of a main part of the canister device 13;

FIG. 3 is an operation explanatory view of the canister device 13;

FIG. 4 is an operation explanation flowchart.

FIG. 5 is an operation state diagram of a second valve that opens and closes according to a change in the internal pressure of the tank 1.

FIG. 6 is an ideal setting state diagram of the canister device.

[Explanation of symbols]

 Reference Signs List 1 fuel tank, 3 refueling gun, 4 internal pressure sensor, 5 pipes, 6 separator, 7 pipes, 8 branch section, 9 pipes (first pipe), 10 pipes (second pipe), 11 first valve, 12th pipe 2 valve, 13 canister device, 14 atmosphere opening, 15 pipes, 18 activated carbon, 20 partition, 21 partition, 100 control unit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02M 25/08 311 F02M 37/00 301

Claims (2)

(57) [Claims] 1. A first conduit for guiding evaporated fuel generated inside a fuel tank to a canister device, and an open state provided in the middle of the first conduit when an internal pressure of the fuel tank does not satisfy a predetermined value. An evaporative fuel supply device for an engine provided with a first valve, wherein a second pipe is provided in parallel with the first pipe to guide the evaporative fuel to the canister device; A second valve that is provided in the middle of the two pipe lines and that is set to an open state until the internal pressure of the fuel tank exceeds a predetermined value during operation of the engine. A first opening of the first conduit is located farther from an atmospheric opening provided in the canister device than a second opening of the second conduit in the canister of the evaporative fuel. Set a difference in , Or
A determination means for determining whether the engine is in the operating state is provided.
The engine operates based on the determination result of the determination means.
When the engine is not running, only the first valve is opened,
During rotation, release both the first valve and the second valve
Fuel supply device for an engine, characterized in that the control is performed as follows . 2. An air passage through an opening of the canister device.
A third conduit communicating with a combustion chamber of the engine;
The distance between the second opening of the road and the opening is
Than the distance between the first opening of one conduit and the opening
The engine according to claim 1, wherein the engine is set to be long.
Evaporative fuel supply system.