JPH07119571A - Fuel additive supplying device - Google Patents

Abstract

PURPOSE:To automatically mix a proper amount of additive into a fuel tank at every time when fuel is fed to the fuel tank by connecting the fuel tank and an additive tank with each other via an additive supplying pipe and arranging their both end opening parts in the specific level. CONSTITUTION:An additive tank 2 is additionally arranged beside a fuel tank 1. Under the full level of fuel, both of the tanks 1, 2 are communicated with each other by means of an additive supplying tube 5. In other words, one of respective opening positions inside the both tanks 1, 2 is opened at the predetermined boundary level height set below a passage, while the other is opened at the height below the boundary level. In the upper part of the additive tank 2, an additive measuring part 3, which forms a space of the predetermined volume between the full level and the boundary level, is arranged. In addition, the upper part, of the additive measuring part 3 and the upper part, of the fuel tank 1 are communicated with each other by a communicating pipe 4. In this way, the additive is easily and surely added to the fuel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel additive supply device, and more particularly to a fuel additive supply device for mixing an appropriate amount of fuel additive into the fuel supplied to an Otto cycle engine using methanol or the like as a fuel.

[0002]

2. Description of the Related Art Conventionally, for example, in a gasoline engine, an action of mixing a fuel additive with gasoline has been generally performed in order to improve combustibility or cleanliness. In this case, it is desirable that the fuel additive is uniformly mixed in the gasoline, and the technique disclosed by the Institute of Invention and Innovation 84-
No. 10272 discloses a device for responding to such a demand, in which an amount of a fuel additive according to the amount of refueling is mixed at any time during refueling.

Here, the apparatus described in the above publication monitors the amount of refueling by means of a fuel gauge arranged in the fuel tank, and for example, every time 1 liter of fuel is supplied, the fuel is injected from the additive injection nozzle into the fuel tank. The above function is ensured by supplying an appropriate amount of fuel additive to.

In this case, the fuel additive is uniformly mixed in the gasoline to be refueled in a large amount, and a greater effect can be obtained as compared with the case where the fuel additive is collectively mixed from the fuel refueling port after refueling. Become.

By the way, in recent years, from the viewpoint of protecting the environment, low-pollution vehicles that use methanol as fuel have been receiving attention, and methanol vehicles equipped with an Otto cycle engine that uses methanol as fuel, and methanol and gasoline. Flexible fuel that uses an Otto cycle engine that can be used as fuel arbitrarily
Vehicles (FFV) etc. have been developed.

In this case, when methanol is used as a fuel for an Otto cycle engine (hereinafter, simply referred to as an engine), the materials of the constituent members are changed to improve the durability and ensure good combustibility. It has been conventionally known that it is necessary to change the air-fuel ratio in order to do so, and in general, a methanol engine was constructed by improving a gasoline engine according to these items.

However, in recent years, it has been found that in an engine that uses methanol as a fuel, the injection amount of the injector tends to change with time as compared with an engine that uses gasoline as a fuel. Then, the present applicant conducted an analysis to pursue the cause, and detected that the above-mentioned difference in change over time was due to the difference in lubricity between methanol and gasoline.

Therefore, when methanol is used as a fuel, it is necessary to impart sufficient lubricity to the methanol, and as a method therefor, it is conceivable to mix an appropriate fuel additive with methanol. At this time, if the device described in the above publication is applied to a methanol engine, the fuel additive will be reliably mixed during refueling,
The certainty of mixing work can be ensured.

[0009]

However, the above-mentioned conventional device requires a mechanism for accurately detecting the amount of fuel to be refueled, a mechanism for injecting an appropriate amount of fuel additive into the fuel tank at a desired timing, and the like. In addition, a control device that appropriately controls these mechanisms is required, and the configuration is not always simple.

On the other hand, in the methanol engine, the concentration of the fuel additive required for imparting sufficient lubricity to methanol is, for example, 0.001 wt% when oleic acid, which is known as an additive, is added. If the concentration exceeds the above range, the effect is obtained, and even if the concentration is higher than that, a uniform concentration is not necessarily required.

That is, the above-mentioned conventional device is of excessive quality as a device for adding a fuel additive in order to ensure the lubricity of methanol in a methanol engine, and has a problem of causing an unreasonable increase in cost. It was

The present invention has been made in view of the above points, and an additive supply pipe in which an additive tank for containing a fuel additive and a fuel tank are opened at a predetermined height in both tanks. To provide a fuel additive supply device that solves the above-mentioned problems by establishing a configuration in which the fuel and the additive can communicate with each other only when a sufficient amount of fuel is supplied to the fuel tank. To aim.

[0013]

[Means for Solving the Problems] The above-mentioned object is to add an additive tank to a fuel tank for accommodating a fuel additive,
A passage communicating between the additive tank and the fuel tank below a full level of fuel, wherein at least one of an opening position in the additive tank and an opening position in the fuel tank is from the passage. An additive supply pipe that is opened at a predetermined boundary level height set below and the other is opened at a height equal to or lower than the boundary level, and is formed above the additive tank to form the full level height and the boundary. An additive measuring section that forms a space of a predetermined volume between the height of the level,
This is achieved by a fuel additive supply device including a communication pipe that connects the upper portion of the additive measuring portion and the upper portion of the fuel tank.

[0014]

In the fuel additive supply device according to the present invention, at least one end of the additive supply pipe is opened at the boundary level in the fuel tank or the additive tank. Therefore, when the fuel exceeding the boundary level is refueled in the fuel tank, the fuel flows into the additive tank through the additive supply pipe.

At this time, since the pressure in the additive tank is kept equal to that in the fuel tank by the communication pipe, the liquid level in the additive tank is equal to that in the fuel tank. When the liquid level in the fuel tank rises, the liquid level in the additive tank also rises, and as a result, the additive measuring section is filled with the mixed liquid of fuel and additive. Then, when fuel is replenished in the fuel tank until it reaches a full level, in the additive measuring section,
The fuel and additive mixture is filled to full level.

After fueling is completed, when the fuel in the fuel tank is consumed and the liquid level thereof is lowered, the fuel and the fuel additive are fed from the additive tank to the fuel tank through the additive supply pipe. The mixed liquid of and flows in. Then, the inflow is until one of the openings of the additive supply pipe is separated from the liquid surface of the fuel or the mixed liquid of the fuel and the additive, that is, the liquid surface is below the boundary level. To continue.

When the liquid level falls below the boundary level, that is, when the liquid level of the additive measuring section reaches the boundary level,
After that, fuel and the like cannot flow through the fuel additive supply pipe, and the inflow of the mixed liquid from the additive tank to the fuel tank is stopped.

That is, in the process of lowering the liquid level in the fuel tank from the full level to the boundary level, a mixed liquid having a volume equal to the volume of the space formed in the additive measuring section is always supplied to the fuel tank. It will be. And
The supply of the fuel additive is surely executed every time the fuel exceeding the boundary level is supplied to the fuel tank.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a fuel additive supply system according to an embodiment of the present invention. The fuel tank 1 is in communication with an injector that supplies fuel to the engine via a fuel pump (not shown), and the fuel according to the valve opening time of the injector is configured to flow out from the fuel tank 1 toward the engine. ing.

The fuel tank 1 is provided with an additive tank 2 containing a fuel additive. An additive measuring section 3 is provided above the additive tank 2. Then, the additive tank 2 is connected to the fuel tank 1 by a communication pipe 4 provided at an upper portion of the additive measuring unit 3 and an additive supply pipe 5 provided at an immediately upper portion of the additive tank 2. Is in communication with.

Here, the communication pipe 4 is opened above the full level when the liquid level when the fuel tank 1 is filled with the full amount of fuel is set to the full level.
Is in communication with. Therefore, in principle, even if the fuel tank 1 is full of fuel, the fuel does not flow into the communication pipe 4.

On the other hand, the additive supply pipe 5 is provided so that the entire path is at a position lower than the above-mentioned full level. Then, one end thereof is inserted up to near the bottom surface inside the fuel tank 1, and the other end is opened into the additive tank 2 at a height set as a boundary level. Therefore, when the fuel is supplied to near the full level in the fuel tank 1, the entire path of the additive supply pipe 5 is located below the liquid level of the fuel, and the pipe is filled with the fuel, so that the fuel tank 1 The additive tank 2 and the additive tank 2 are practically in conduction with the fuel.

That is, when the liquid level of the fuel in the fuel tank 1 exceeds the height of the additive supply pipe 5, the fuel in the fuel tank 1 flows through the additive supply pipe 5 and flows into the additive tank 2. However, in the process in which the liquid level rises thereafter, the liquid level of the additive measuring section 3 provided above the additive tank 2 becomes
It will be kept the same as the liquid level inside.

On the other hand, when the liquid level in the fuel tank 1 is lowered due to such a situation, the liquid level of the additive measuring section 3 follows the lowering of the liquid level in the fuel tank 1 until the liquid level reaches the boundary level. descend. When the liquid level drops below the boundary level, the gas introduced from the communication pipe 4 flows into the additive supply pipe 5 and the additive tank 2 is virtually shut off from the additive supply pipe 5. Becomes Therefore, thereafter, even if the liquid level in the fuel tank 1 is lowered, the liquid level in the additive tank 2 is not lowered by it.

By the way, regarding the liquid level rise and the liquid level drop in the additive tank 2, the supply or demand of fuel or additive is performed between the fuel tank 1 and the additive tank 2 through the additive supply pipe 5. It is due to that.

Assuming that the volume of the space formed between the full level and the boundary level in the additive measuring section 3 is V as shown in FIG. 1, a fuel having a volume V from the fuel tank 1 is supplied at the time of refueling. It has been distributed to the additive tank 2. Then, in the process of finally lowering the liquid level of the additive measuring unit 3 to the boundary level as the liquid level in the fuel tank 1 is lowered, the mixed liquid of the fuel and the additive having the volume V is added to the additive tank 2 From the fuel tank 1 to the fuel tank 1.

Therefore, according to the fuel additive supply system of the present embodiment, every time the fuel is refueled and the fuel is consumed, the mixed liquid of the fuel and the fuel additive having the volume V is stored in the fuel tank 1. Can be mixed in.

By the way, the lowering of the liquid level in the fuel tank 1
This is a phenomenon caused by the consumption of fuel in the engine, and there is a certain limit to the rate of decrease. Therefore, it suffices that the mixed liquid to be circulated from the additive tank 2 to the fuel tank 1 is sufficiently time-consuming, and it is not necessary to secure a large flow rate thereof.

Therefore, a proper orifice is provided in the path of the additive supply pipe 5 to secure sufficient flow resistance, and the circulation of the fuel and the fuel additive is practically achieved when the fuel exists near the full level. It is possible to prevent it.

According to this structure, when the liquid level rises from the level below the boundary level to near the full level, the amount of fuel supplied into the additive tank 2 is substantially the level rise of the additive metering unit 3. Can be approximated as V itself. If V can be ignored in the ratio of the capacity of the additive tank 2 to V, it can be considered that the fuel additive having a volume of V has flowed into the fuel tank 1 when the liquid level drops. It is possible to suppress fluctuations in the amount of additive flowing out for each refueling.

By the way, the fuel additive supply device of this embodiment is suitable as a device for securing the additive so that the methanol has a proper lubricating action when methanol is used as the fuel.

That is, as described above, when methanol is used as the fuel, the amount of change over time in the injection amount of the injector is different due to the difference in lubricity between methanol and gasoline.

FIG. 2 is a diagram for explaining the difference in the injection amount, FIG. 2 (A) is an opening / closing valve control signal supplied to the injector, and FIG. 2 (B) is the operating state of the injector after a change over time. (In the figure, the solid line shows the initial case, and the broken line shows the case after change with time).

As shown in the figure, the responsiveness to the control signal is greatly deteriorated after the change with time as compared with the initial stage.
This phenomenon is due to the increased sliding resistance of the internal components of the injector when methanol was used as the fuel.

Therefore, if the lubricity of methanol used as a fuel can be improved, it is possible to prevent the above-mentioned adverse effects due to the use of methanol as a fuel.

FIG. 3 shows the result of an experiment conducted to understand the effect of improving the lubricity when oleic acid was added to methanol as an additive. As shown in the figure, when oleic acid was added, the friction coefficient was halved compared to the case of only methanol (sample number N = 4) even when the concentration was only 0.001 wt% or more. I understand. This means that if the addition of oleic acid does not affect the flammability of methanol, there is no problem even if the concentration exceeds this, and therefore a desired effect can be sufficiently obtained with an extremely rough addition amount. It means that.

On the other hand, the fuel additive supply system of this embodiment can supply the additive (and the mixed liquid of fuel) of the volume V to the fuel tank 1 for one refueling as described above. For example, assuming that the volume of the fuel tank 1 is 50 liters, a desired lubricating effect can be sufficiently obtained by ensuring an added concentration of 0.01 wt% with V = 5 cc.

In this case, if the capacity of the additive tank is about 5 liters, the mixed liquid flowing from the additive tank 2 to the fuel tank 1 initially contains 99.9 wt% of the additive. And is effectively 5cc
The additive can be regarded as flowing into the fuel tank 1, and 1000 times of refueling can be dealt with, and a sufficient amount can be secured for the life of the vehicle.

As described above, according to the fuel additive supply system of the present embodiment, the fuel supply is performed without providing a mechanism for detecting the fuel supply amount, a mechanism for injecting the fuel additive, a device for controlling them, and the like. The function of surely mixing an appropriate amount of fuel additive with each fuel additive can be realized with an extremely simple configuration.

When this device is combined with a methanol engine, the harmful effects of the methanol engine can be eliminated without a significant increase in cost, and the practical durability of the methanol vehicle, FFV, etc. can be improved. it can.

In the fuel additive supply system shown in FIG. 1, the end of the additive supply pipe 5 that opens into the fuel tank 1 is located near the bottom of the fuel tank 1 and the additive tank. The end portions that open inside 2 are opened at the boundary level, but the invention is not limited to this. That is, as shown in FIG. 4, fuel is added by using an additive supply pipe 6 having an end opening in the additive tank 2 near its bottom surface and an end opening in the fuel tank 1 at a boundary level. You may comprise an agent supply apparatus. Further, in the above embodiment, oleic acid is used as the fuel additive, but the present invention is not limited to this, and other higher fatty acids may be used.

[0042]

As described above, according to the present invention, a mechanism for measuring the fuel refueling amount, a mechanism for injecting an appropriate amount of the fuel additive into the fuel tank, a control device for controlling these, etc. It is possible to realize with a simple configuration without the need for. Then, every time the fuel is completely filled in the fuel tank, an appropriate amount of the fuel additive can be surely mixed into the fuel tank at the time of refueling.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a fuel additive supply device that is an embodiment of the present invention.

FIG. 2 is a diagram for explaining how an injector response characteristic changes with time when methanol is used as a fuel.

FIG. 3 is a diagram for explaining a lubricating effect when oleic acid is mixed into methanol as an additive.

FIG. 4 is a configuration diagram of a fuel additive supply device according to another embodiment of the present invention.

[Explanation of symbols]

 1 Fuel tank 2 Additive tank 3 Additive measuring part 4 Communication pipe 5,6 Additive supply pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Imamura 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. (72) Inventor Masao Kinoshita 1 of 41, Nagakute-cho, Aichi-gun, Aichi-gun Toyota Central Research Institute Co., Ltd. (72) Inventor Hitoshi Ichikawa 1-1-1, Showa-cho, Kariya city, Aichi prefecture Nihondenso Co., Ltd.

Claims (1)

[Claims] 1. An additive tank provided in a fuel tank for accommodating a fuel additive, and a passage communicating the additive tank and the fuel tank below a full fuel level, the additive tank At least one of the opening position in the tank and the opening position in the fuel tank is opened at a predetermined boundary level height set below the passage, and the other is opened at a height below the boundary level. An agent supply pipe, an additive metering part formed on the upper part of the additive tank and forming a space of a predetermined volume between the full level height and the boundary level height, and an upper part of the additive metering part And a communication pipe communicating with the upper portion of the fuel tank.