JP2000303815A - Method and apparatus for improving lubrication of sliding surface of fuel injection system in diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the infiltration of the emulsion fuel to a sliding surface, exclude the infiltrated emulsion fuel and improve the lubricating performance by mounting an lubrication fuel inlet on an injection pump or on the way of a sliding surface of a fuel injection valve. SOLUTION: In a Bosch type fuel injection pump, emulsion fuel is sucked from an fuel inlet 17 accompanying the reciprocation of a plunger 21 by the rotation of a cam 25, and supplied to a fuel injection valve through an fuel outlet 19 after the rise of pressure. In this case, a lubrication fuel inlet 20 is formed on a cylinder provide with a plunger 21, and an oil groove for lubrication is formed on a sliding surface between the plunger 21 and the cylinder so that the lubrication fuel (pure fuel: fuel which does not contain water and fuel added with additives) is supplied over the circumference of the plunger 21. The pressure of this pure fuel is determined to be higher than an average pressure to be added to an injection chamber, whereby the intrusion of the emulsion fuel into the sliding surface between the plunger 21 and the cylinder can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates mainly to an emulsion operation technique as a countermeasure against low NOx in a diesel engine, and relates to a countermeasure for improving lubricity of a sliding surface of an emulsion fuel in which lubricity is concerned.

[0002]

2. Description of the Related Art Emulsion fuel is produced by adding water to fuel. When this fuel is used in a diesel engine, the emulsion fuel acts on sliding surfaces of a fuel injection pump or an injection valve. It was feared that problems such as an increase in the amount of leakage and burn-in due to deterioration of lubricity were caused.

[0003] The reason that the emulsion fuel is inferior in lubricity to the pure fuel is that a part of the oil film on the sliding surface is replaced by water. As the amount of water added increases, the base fuel becomes less pure. Lubricity is reduced. To compensate for this, conventionally, additives such as additives for improving lubrication are introduced into the fuel to improve the lubricity of the base fuel and to maintain the required lubricity on the sliding surface even when water is added. Emulsion fuel was used.

[0004]

However, the injection of the lubricant needs to improve the lubricity of the base fuel.
About 0.3 to 2% of the fuel consumption is required, and a reduction in operating cost has been demanded.

[0005]

SUMMARY OF THE INVENTION Since an emulsion fuel is prepared by adding water to a base fuel, it has been found that there is no problem even if pure fuel is added to the sliding surface. or,
Even when the additive is used for the sliding surface, it was found that by injecting the additive into the sliding surface in a targeted manner, the additive can be used only in a necessary part without waste, so that an extremely small amount with respect to the engine consumption is sufficient.

Therefore, a lubricating fuel inlet for injecting pure fuel is provided in the middle of the sliding surface of the fuel injection pump or the injection valve,
By forcibly injecting water-free fuel or fuel with an additive added thereto, it is possible to prevent the emulsion fuel from entering the sliding surface, or to wash out the entering emulsion fuel from the sliding surface, A good lubrication state can always be maintained.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a basic flowchart for implementing the present invention in a fuel injection system of a diesel engine using an emulsion fuel. In the figure, fuel supplied from a service tank (1) is boosted by a booster pump (2), measured by a transmission type flow meter (3), and supplied to an emulsion fuel line (12).

[0008] The supplied fuel is mixed with the emulsion fuel returned from the engine, and is supplied to the pressurized circulation pump (4).
Pressurized to the required pressure by the mixer (5)
The fuel that has just been metered and the water proportional to it are emulsified and supplied to the fuel injection pump (16). In the fuel injection pump, a plunger (21) supplies a required amount to a fuel injection valve (29) via a delivery valve (26), and the fuel is injected into a cylinder of an engine from a fuel injection nozzle (31) and burns. After the water is once stored in the water tank (7), the proportional water pump (8) supplies the water to the mixer in proportion to the fuel flow rate. Feedback control is performed by a water transmission type flow meter (9) as necessary,
More accurate water content can be obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 2 is an example of a structural diagram of a Bosch type fuel injection pump according to the present invention. The emulsion fuel is supplied to the fuel inlet (1
7), the fuel is supplied to the fuel injector via the fuel outlet (19) by the plunger (21).
During the injection process of the plunger, the fuel return port (18) is opened from an obliquely opened opening called a lead (22) to the injection chamber (5).
The injection amount is adjusted by discharging the high-pressure fuel of 1).

Since the lead is machined into a plunger, by rotating a spline portion called a driving face (24) by a rack (50), the positional relationship between the fuel return port and the lead changes, and the fuel injection amount changes. Becomes possible. Vertical movement for injection is performed by rotation of a cam (25) synchronized with the engine speed.

Generally, lubrication of the lower portion including the driving face is performed by lubricating oil.
The lubrication of the upper part from 3) is performed by fuel oil. Then, usually, in order to prevent mixing of the two, the fuel that has passed through the oil groove is discharged to the outside as oil leakage.

In the embodiment, a lubricating fuel inlet (20) is newly provided in the cylinder (27), and a lubricating oil groove (28) is provided so that the lubricating fuel can spread around the plunger.
Pure fuel was supplied here. The pressure of the pure fuel was higher than the average pressure applied to the injection chamber. That is, the pressure of the injection chamber, which is about 90-100 MPa at the time of injection, is about 0.5-1.0 MPa except for the moment of injection, so that a pressure exceeding the average pressure per stroke is applied to the lubrication line. The supply prevents the emulsion fuel from entering the sliding surface between the plunger and the cylinder,
Conversely, pure fuel is discharged little by little to the injection chamber side and the lower drain side.

[0013] Therefore, lubrication of the sliding surface between the plunger and the cylinder is performed with almost pure fuel, and in terms of reliability, almost the same state as when no emulsion fuel is used was achieved. In addition, even with an injection pump in which the fuel oil mixes with the lubrication system, it is possible to prevent the emulsion fuel oil mixed with water from entering the lubrication oil, and the reliability does not decrease. Was. The present invention is not limited to the Bosch type in the embodiment, but may be applied to any reciprocating fuel injection pump having a sliding surface through which lubricating fuel can be injected.

An embodiment of a method for improving lubrication of a Bosch type fuel injection valve will be described with reference to FIG.
Injected fuel pool supplied from 3) through an injection route (35) machined inside the nozzle body (30), through a groove cut on the mating surface with the injection nozzle (31) It is led to (37). Nozzle needle (32)
When the pressure overcoming the spring that suppresses the pressure is applied to the injected fuel pool, the nozzle needle is raised and communicated with the injection port (39) opened at the tip of the injection nozzle, and fuel is injected from the injection port. Since the nozzle needle moves up and down at each injection timing as described above, it is necessary to lubricate the gap between the injection nozzle and the nozzle body, but this lubrication has been performed with fuel oil. Normally, the fuel that has lubricated the gap is supplied to a leak nozzle (52) provided in the upper spring portion.
Is discharged to the outside.

The lubricating fuel of the present invention is provided by a newly provided lubricating fuel inlet (04) and a lubricating fuel line (36).
It reaches the mating surface with the injection nozzle. The lubricating oil groove (3) passes through the groove for the lubricating fuel cut inside the fuel groove.
8). Since the delivery valve described in the above-described injection pump is installed in the injected fuel reservoir, the backflow of the fuel is prevented, and a considerably high pressure is applied even at times other than the injection timing. For this reason, it is difficult to maintain the average pressure of the lubricating fuel oil groove (38) higher than the injected fuel pool. For this reason, the gap between the nozzle need above the lubricating fuel oil groove and the injection nozzle or nozzle body is slightly enlarged, and the amount of leakage of the lubricating fuel is increased to dilute the emulsion fuel and maintain lubricity. is there.

Therefore, the lubrication of the fuel injection valve tends to have a slightly worse lubricating property than the method of completely lubricating with a pure fuel. Therefore, it is desirable to add a chemical such as a lubricant if possible. Fortunately, however, the nozzle body, including the injection nozzle and nozzle needle, is treated as a consumable item in diesel engines, and there is little economic loss even without performing strict lubrication management as with an injection pump. Whether or not to use a lubricant can be left to the discretion of the user. The present invention is not limited to the Bosch type in the embodiment, but may be applied to any other fuel injection valve having a sliding surface capable of injecting lubricating fuel with a reciprocating fuel injection valve.

An embodiment of the lubricating fuel supply device will be described with reference to FIG. 4. As the lubricating fuel supply pump (10), a gear pump capable of discharging to a high pressure was used. Maximum discharge pressure 13
MPa. The pressure transmitter (42) detects the discharge pressure of the lubricating fuel supply pump and sends a pressure signal to the pressure regulator (43). The pressure regulator sends a speed signal to the lubricating fuel VVVF device (44) to adjust the rotational speed of the lubricating fuel supply pump so that the pressure becomes a preset pressure.

The speed signal from the pressure regulator is processed by the cascade calculator (46), and the lubricant VVVF device (45) is processed.
By sending a speed signal to the lubricant pump, it is possible to cascade-control the lubricant pump (41) also constituted by a gear pump, and it is possible to supply necessary additives in proportion.

In the case of this device, a limiter is provided for the speed signal of the pressure regulator, and when the speed signal exceeds a certain speed value, a warning that the amount of leak is increasing can be issued, and the pressure can be reduced. It is also easy to output an alarm signal to stop the water addition of the emulsion when it has decreased. When the fuel pressure is increased to about 10 MPa, the excess can be pressure-controlled by a constant-speed pump using a relief valve. However, since the energy added to the fuel is large, heat generation cannot be ignored. Therefore, it is necessary to consider an oil cooling device as a countermeasure. When the rotation speed control is performed as in this embodiment, an increase in the oil temperature can be prevented, so that the apparatus is simplified and energy is saved.

In FIG. 1, the fuel from the fuel service tank (1) is used. However, this is generally a fuel with poor fluidity such as C heavy oil. In the case of fuel with poor fluidity, it is necessary to take measures to maintain a temperature at which fluidity can be maintained. However, in the case of a system using a diesel engine compatible with C heavy oil, A heavy oil can also be used at the same time, so a device for maintaining the temperature by using A heavy oil as a lubricating fuel is required. It becomes unnecessary.

Since the lubricant for lubricating fuel used in the present invention also has a role of diluting the emulsion fuel, it is advantageous to have an action as an emulsifier for emulsifying water. In addition, since the fuel is partially mixed with fuel and burned by the engine, it is not desirable that the fuel contains components such as metals which have a bad influence on combustion. Generally, esters of higher fatty acids and polyhydric alcohols and ethers of higher alcohols and polyhydric alcohols are desirable. It is also effective as a countermeasure against corrosion to the sliding surface to include an anticorrosive containing no inorganic components such as amines derived from higher fatty acids, if necessary.

[0022]

The effect of the emulsion fuel on the sliding surface differs depending on the usage conditions of the engine, design standards, etc.
According to the method for injecting pure fuel into a sliding surface according to the present invention, an emulsion fuel can be used with almost no change in a conventional design standard, so that an extremely low-cost and highly reliable engine system is obtained. Even if pure fuel is injected into all of the fuel injection pump and the fuel injection valve, it is estimated that only about 1 to 2% of the rated fuel consumption is required because the amount of fuel substantially equal to the conventional fuel leak amount may be injected. . Therefore, when the additive is injected or when 2% of the additive is injected with respect to the pure fuel of 1 to 2%, the fuel consumption is 0.1% in view of the rated fuel consumption.
A sufficient effect can be expected with an extremely small additive amount of 04%. Furthermore, by installing a flow meter in this pure fuel injection line and measuring the consumption, the wear state of the sliding surface can be confirmed, which proved to be advantageous from the viewpoint of maintenance.
Also, the method of using a lubricant in combination is considered to be effective not only when an emulsion fuel is used but also when a fuel having poor lubricity must be used.

[Brief description of the drawings]

FIG. 1 is a basic flowchart of the present invention.

FIG. 2 Bosch type fuel injection pump

FIG. 3 Bosch type fuel injection valve

FIG. 4 is a flowchart of a lubricating fuel supply device.

[Explanation of symbols]

 (1) Fuel service tank (2) Booster pump (3) Fuel transmission type flow meter (4) Pressurized circulation pump (5) Mixer (6) Pressure regulating valve (7) Water tank (8) ) Proportional water pump (9) Water transmission type flow meter (10) Fuel supply pump for lubrication (11) Fuel line (12) Emulsion fuel line (13) High pressure fuel line (14) Lubricating fuel line (16) Injection pump (17) Fuel inlet (18) Fuel return (19) Fuel outlet (20) Lubricating fuel inlet (21) Plunger (22) Lead (23) Oil groove (24) ) Driving face (25) Cam (26) Delivery valve (27) Cylinder (28) Lubrication oil groove (29) Injection valve (30) Nozzle body (31) Injection nozzle (32) Nozzle (33) ... fuel inlet (34) ... lubricating fuel inlet (35) ... injection route (36) ... lubrication route (37) ... injected fuel reservoir (38) ... lubricating fuel oil groove (39) ... injection port ( 40) Lubricant tank (41) Lubricant pump (42) Pressure transmitter (43) Pressure regulator (44) VVVF device for lubricating fuel (45) VVVF device for lubricant (46) Cascade Arithmetic unit (50) ... Rack (51) ... Injection chamber (52) ... Leak nozzle

Claims (4)

[Claims] In a diesel engine injection pump using an emulsion fuel, a sliding surface between a cylinder (27) and a plunger (21) is provided between a fuel inlet (17) and an oil groove (23) of the plunger. A method for improving lubrication of a sliding surface of a fuel injection pump of a diesel engine in which a lubricating fuel inlet (20) is provided and a non-hydrous fuel is injected to thereby lubricate the emulsion fuel. 2. In a diesel engine injection valve using an emulsion fuel, a new lubrication fuel inlet (34) and a lubrication route (36) are newly provided in the nozzle body (30), and the nozzle body (30) is provided above the injection fuel reservoir (37). Injection of non-hydrous fuel into the sliding surface between the nozzle needle (32) and the injection nozzle (31) or the nozzle body causes the sliding surface of the fuel injection valve of the diesel engine to be lubricated by the emulsion fuel. How to improve lubrication. 3. An emulsion fuel supply line for a diesel engine comprising a booster pump (2), a transmission flow meter (3), a pressurized circulation pump (4), a mixer (5) and the like. By branching a pipe from a part of 11), installing a lubricating fuel supply pump (10), and connecting this pure fuel to the lubricating fuel inlet of claim 1 or claim 2, lubricity by emulsion fuel is a concern. To improve the lubrication of the sliding surface of the fuel injection system of diesel engines. 4. A fuel injection system for a diesel engine in which a lubricant tank (40) and a lubricant pump (41) are provided, a lubricant is added to the lubricating fuel, and the lubrication of the sliding surface is further improved. Moving surface lubrication improvement device.