JPH0413407Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention maintains the fuel oil in the fuel oil tank at a constant pressure with a pressure regulating valve and sends it to the pressure accumulator with a pre-booster pump, and also controls the fuel oil discharged from the pressure accumulator. A fuel oil supply for a diesel engine in which oil is sent to a heater by a booster pump, heated fuel oil is supplied to a diesel engine, and excess fuel oil not consumed by the diesel engine is returned to the pressure accumulator via a pressure regulating valve. The present invention relates to a fuel oil supply device for a diesel engine that can rationally process vapor returned from a pressure accumulator to a fuel oil tank.

Prior Art FIG. 5 shows a piping system of a fuel oil supply system for a diesel engine, which is the background of this invention. 1 in the diagram
is a pre-booster pump, and the fuel oil discharged from the fuel oil tank 5 by this pre-booster pump 1 is:
It is temporarily stored in the pressure accumulator 3. Above fuel oil tank 5
In order to keep constant the pressure of the fuel oil sent to the pressure accumulator 3 by the prebooster pump 1, a pressure regulating valve 6 is provided to short-circuit the discharge side and the suction side of the prebooster pump.

Further, a fuel oil supply line 9 having a booster pump 7 and a heater 8 on the way is connected to the pressure accumulator 3, and the fuel oil pressurized by the booster pump 7 and heated by the heater 8 is supplied to the pressure accumulator 3. diesel engine 10
is supplied to

Excess fuel oil that is not consumed by the diesel engine 10 is returned to the pressure accumulator 3 via the pressure regulating valve 11. The pressure regulating valve 11 allows the diesel engine 10 to
The pressure of fuel oil supplied to is set.

In recent years, diesel engines that use low-quality heavy oil with high viscosity as fuel oil have been developed. is necessary. For this purpose, the heater 8 heats the fuel oil to an appropriate viscosity in order to help atomize the fuel oil injected from the fuel valve.

The temperature of the fuel oil heated in this way is high enough to exceed the flash point, for example, and the temperature of the fuel oil is high enough to exceed the flash point.
Fuel heated to such a high temperature is returned to the

When fuel oil is heated to a high temperature as described above, water in the fuel oil turns into vapor, but the generation of such vapor should be avoided from the viewpoint of fire prevention and prevention of fuel oil deterioration. Therefore, the pressure accumulator 3 is pressurized by the pre-booster pump 1.

When the diesel engine 10 is restarted from a stopped state, sufficient pressure must be applied to the fuel oil from the beginning of the restart to prevent vapor from being generated in the fuel oil. For this reason, it is necessary to store a certain amount of pressurized air in the pressure accumulator 3 together with the fuel oil by the pre-booster pump.

Problems with the Prior Art By the way, in the conventional fuel oil supply system for diesel engines as shown in Figure 5, air that gets mixed in when the engine or fuel oil filter is opened, or gets mixed in with the fuel oil supplied from the fuel oil tank. When the volatile components contained in the air particles and fuel oil become vapor and accumulate in the pressure accumulator 3 more than necessary, the vapor discharge device 3' installed inside the pressure accumulator or at the outlet of the pressure accumulator removes the vapor more than necessary. The structure is such that the accumulated vapor is returned to the fuel oil tank 5 via the vapor discharge pipe 12.

Therefore, the high temperature vapor discharged from the vapor discharge pipe 12 into the fuel oil tank 5 is discharged from the vapor discharge pipe 13. Such high-temperature vapor is normally water vapor with volatile components of fuel oil and fine fuel oil attached, so if it is discharged from the vapor extraction pipe 13, there is a risk of ignition. It also had the disadvantage of contaminating the surface.

Further, the vapor discharge device 3' attached to the pressure accumulator is required to have integrity in preventing leakage and reliability in vapor discharge operation.

Purpose of the invention Therefore, the purpose of the present invention is to remove the vapor accumulated in the pressure accumulator in excess of the necessary amount into fuel by combining it with the excess fuel oil discharged from the pre-booster pump without using a vapor discharge device. Return to oil tank
It is an object of the present invention to provide a fuel oil supply device that does not condense water by cooling with excess fuel oil and inject it to the outside as high-temperature vapor.

Structure of the invention The main means adopted by the invention to achieve the above object is to send fuel oil in the fuel oil tank to the pressure accumulator using a pre-booster pump while keeping it at a constant pressure with a pressure regulating valve, and to pump it out from the pressure accumulator. For diesel engines, the heated fuel oil is sent to the heater by a booster pump, the heated fuel oil is supplied to the diesel engine, and the excess fuel oil that is not consumed by the diesel engine is returned to the pressure accumulator via a pressure regulating valve. In the fuel oil supply device, a connecting pipe through which fuel oil and/or vapor in the pressure accumulator flows is provided protrudingly at a predetermined position on the side of the pressure accumulator, and the prebooster pump is connected to the connecting pipe, and A fuel oil return pipe for returning fuel oil and vapor to the fuel oil tank is connected to a portion of the connecting pipe above the connection position of the pre-booster pump to the connecting pipe, and the fuel oil return pipe is connected to the above pressure. A control valve is installed, and a fuel oil circulation circuit is constructed that passes through the fuel oil tank, prebooster pump, connecting pipe, and pressure regulating valve. This fuel oil supply device for a diesel engine is characterized in that vapor is returned to a fuel oil tank through a pressure regulating valve along with excess fuel oil from the prebooster pump directed toward the pressure accumulator.

Function Since the discharge amount of the prebooster pump is greater than the amount of fuel oil consumed by the engine, excess fuel oil is always returned to the fuel oil tank from the pressure regulating valve. The vapor accumulated in the pressure accumulator more than necessary is discharged to the fuel oil return pipe together with the excess fuel oil from the prebooster pump. Since the fuel oil return pipe is connected to the fuel oil tank at atmospheric pressure, the vapor discharged from the pressure regulating valve is depressurized here and cooled by the surplus fuel oil, and the volatile vapor of the fuel oil is The water vapor condenses and returns to the fuel tank. Therefore, the vapor exhaust pipe mainly discharges air that got mixed in when the engine or fuel oil filter was opened, and high-temperature vapor containing fine fuel oil adhering to the volatile matter and water vapor of the fuel oil is ejected. Such inconveniences are avoided.

Embodiments Next, embodiments embodying the present invention will be described with reference to FIGS. 1 to 4 to provide an understanding of the present invention.

FIG. 1 is a fuel oil piping system diagram of a diesel engine fuel oil supply device according to an embodiment of the present invention;
FIG. 2 shows a first fuel oil supply device according to another embodiment.
3 and 4 are side sectional views of a pressure accumulator portion that can be used in the embodiment device shown in the above or in FIG. 2. Here, the oil supply pipe 14 in FIG. 3 and the oil supply pipe 14 and vapor communication pipe 15 in FIG. 4 each mean a connecting pipe.

In the following embodiments, the same reference numerals are used for the same elements as those of the conventional fuel oil supply system shown in FIG. 5.

Further, the following example is only one specific example of the present invention, and is not intended to limit the technical scope of the present invention.

As can be easily understood by comparing FIG. 1 and FIG. 5, in the diesel engine fuel oil supply system shown in FIG. The structure of the fuel oil system and the structure of the pressure accumulator 3 are significantly different from the conventional device shown in FIG.

That is, in this embodiment, the pressure accumulator 3 is
As shown in the figure, it is composed of a vertical cylindrical body, is not equipped with a vapor discharge device 3', and has a fuel supply pipe 14 horizontally protruding from its approximately middle part, into which fuel oil is returned. A conduit 4 is connected. A pressure regulating valve 6' is connected in the middle of the fuel oil return pipe 4. Therefore, the fuel oil tank 5, the prebooster pump 1, the oil supply pipe 1 of the pressure accumulator 3
4. A pressurized circulation circuit is constituted of a fuel oil return pipe 4 and a pressure regulating valve 6', and the pressure within the pressure accumulator 3 is set to the operating pressure of the pressure regulating valve 6'. Furthermore, the inside of the fuel oil return pipe 4 from the pressure regulating valve 6' to the fuel oil tank 5 is at atmospheric pressure.

Therefore, the pressure in the pressure accumulator 3 increases as the pre-booster pump 1 is driven, and when it eventually reaches the operating pressure of the pressure regulating valve 6', the pressure regulating valve 6' opens and the fuel oil from the pre-booster pump 1 is discharged. The surplus fuel oil is returned to the fuel oil tank 5 through the fuel oil return pipe 4. At this time, when a certain amount of vapor is accumulated in the pressure accumulator 3, the excess high temperature vapor is discharged to the fuel oil return pipe 4, and is mixed with the excess fuel oil from the pre-booster pump 1. While returning to the fuel oil tank 5, it is cooled by the surplus fuel oil, the vapor of volatile content of the fuel oil becomes liquid, and the water vapor is condensed and returns to water, thus removing high temperature from the fuel oil tank. Inconveniences such as vapor being ejected together with fuel are avoided.

Next, with reference to FIGS. 3 and 4, install the oil supply pipe 1.
The structure and function of part 4 will be explained.

The oil distribution pipe 16 that introduces the fuel oil discharged from the pre-booster pump 1 into the pressure accumulator 3 is connected to the pressure accumulator 3.
As shown in FIGS. 3 and 4, it is connected to the fuel supply pipe 14 without being connected to the prebooster pump 1, and the engine consumption amount of the fuel oil discharged from the prebooster pump 1 is supplied to the pressure accumulator 3, and the fuel Only the surplus fuel oil from the prebooster pump 1 returns to the fuel oil tank 5 from the oil return pipe 4, and the fuel oil in the pressure accumulator 3 does not return to the fuel oil tank 5 from the fuel oil return pipe 4. It needs to be shaped. This is because high-pressure, high-temperature fuel oil heated by the heater 8 is stored in the pressure accumulator 3, whereas fuel oil at a relatively lower temperature than the fuel oil tank 5 is stored in the oil distribution pipe 16. This is because the comparatively low-temperature fuel oil is returned from the fuel supply pipe 14 to the fuel oil tank 5 from the fuel oil return pipe 4 as surplus fuel oil.

In addition, since the prebooster pump 1 is designed to have a discharge amount larger than the maximum engine fuel oil consumption (Q max.), under normal operating conditions, the relatively low temperature fuel oil always exceeds the engine fuel oil consumption. Q is supplied to the pressure accumulator, and at the same time, it is returned to the fuel oil tank 5 from the fuel oil return pipe 4.

FIG. 3 shows a device for discharging the vapor accumulated in the pressure accumulator 3 beyond necessity through the oil supply pipe 14, and FIG. 4 shows a device for discharging the vapor through the vapor communication pipe 15.

In the case of FIG. 3, vapor flows back into the pressure accumulator 3 by setting the height of the valve seat 6a of the pressure regulating valve 6' higher than the upper end of the oil supply pipe 14 when viewed in cross section. It is possible to prevent this, keep the liquid level of fuel oil in the pressure accumulator 3 constant, and accumulate a certain amount of pressurized air (vapor) in the pressure accumulator 3. In this case, the upper limit of the normal liquid level is the upper end when viewed in cross section of the oil supply pipe 14, and the lower limit of the normal liquid level is set by the shape of the oil supply pipe 14 and the maximum engine fuel oil consumption Q max.
Therefore, the normal liquid level is determined by the engine fuel oil consumption Q, and when Q is zero, it is the upper limit of the normal liquid level, and Q
It decreases as Q max. increases, and reaches the lower limit of the normal liquid level at Q max., and is maintained between the upper limit of the normal liquid level and the lower limit of the normal liquid level.

When the device is used for the first time, if vapor is not accumulated in the pressure accumulator 3 and the liquid level is higher than the upper limit of the normal liquid level, the liquid level is increased until the normal liquid level is equal to the engine fuel oil consumption Q. When vapor accumulates in the pressure accumulator 3 and exceeds the amount corresponding to the engine fuel oil consumption Q, the excess vapor is transferred to the fuel supply pipe 1.
4 to the fuel oil return pipe 14, and the liquid level is maintained at a normal level commensurate with the engine fuel oil consumption Q.

In this case, the diameter and length of the oil supply pipe 14 are
The pipe is thin or long so that the relatively low temperature fuel oil returned from the fuel oil return pipe 4 to the fuel oil tank 5 in the fuel supply pipe 14 does not replace the high temperature fuel oil in the pressure accumulator 3 even if the fuel oil is zero. Even if the above-mentioned Q is the maximum engine fuel oil consumption Q max., it must be designed to be thick or short so as to create a vapor space.

In the case of Figure 4, in terms of the positional relationship in the height direction,
The connection parts 15a and 15b of the vapor communication pipe 15 to the pressure accumulator 3 and the fuel oil return pipe 4 are made at the same height,
In addition, as seen in the cross section of the fuel supply pipe 14, from the upper end thereof, from the connection contact 4a with the fuel oil return pipe 4 to the pressure accumulator 3, the piping for the maximum flow rate (maximum engine fuel oil consumption Q max.) in the fuel supply pipe 14. By connecting the valve seat 6a of the pressure regulating valve 6' higher than the connection positions 15a and 15b of the vapor connecting pipe, it is possible to prevent vapor from flowing back into the pressure accumulator 3, and to reduce the pressure accumulation. Keep the liquid level in vessel 3 constant,
A certain amount of pressurized air (vapor) can be accumulated. In this case, the upper limit of the normal liquid level is vapor connection pipe 15.
The lower limit of the normal liquid level is higher than the upper limit of the normal liquid level when viewed from the cross section of the connecting portion 15a of the fuel oil return pipe 4.
The piping resistance in the fuel supply pipe 14 from the connection point 4a to the pressure accumulator 3 is set to be lower than the maximum engine fuel oil consumption Q max. Therefore, as in the case of Fig. 3, the normal liquid level is determined by the engine fuel oil consumption Q, and when Q is zero, the normal liquid level is the upper limit, and as Q increases, it decreases, and at Q max. This is the lower limit of the normal liquid level and is maintained between the lower limit of the normal liquid level.
Also, when the liquid level is higher than the upper limit of the normal liquid level, the pressure accumulator 3
The vapor connecting pipe 15 is designed to prevent the high temperature fuel oil inside the vapor connecting pipe 15 from short-circuiting from the vapor connecting pipe 15 to the fuel oil return pipe 4.
is an inverted U-shaped tube, and its neck 15c is the pressure accumulator neck 3.
It is necessary to make it higher than a.

In this way, in the pressure accumulator 3, a certain amount of vapor is accumulated above the oil level L at a certain level, and a certain amount of fuel oil is accumulated below it. When restarting after stopping, etc.
The accumulation of pressure by the vapor allows fuel oil under sufficient pressure to be continuously supplied to the diesel engine,
It is possible to prevent the generation of vapor in the fuel oil due to pressure reduction at the time of restart.

Further, in the embodiment shown in FIG. 2, a vapor separation pipe 17 is provided between the fuel oil return pipe 4 and the inlet of the pre-booster pump 1, and the fuel sent out by the pre-booster pump 1 is It circulates through the fuel supply pipe 14, the pressure regulating valve 6', and the vapor separation pipe 17, and the vapor separation pipe 17 is also opened to the fuel oil tank section through the vapor discharge pipe 12 and set to atmospheric pressure. Therefore, the oil level in the vapor separation pipe 17 and the oil level in the fuel oil tank 5 match, and the amount of fuel consumed by the diesel engine 10 flows from the fuel oil tank 5 to the prebooster pump 1. Therefore, by providing a flow meter 18 in this conduit, the amount of fuel oil actually consumed by the diesel engine 10 can be measured.

Effects of the invention As described above, the present invention has the following advantages: The fuel oil in the fuel oil tank is maintained at a constant pressure by the pressure regulating valve and is sent to the pressure accumulator by the pre-booster pump, and the fuel oil discharged from the pressure accumulator is transferred to the booster. In a fuel oil supply device for a diesel engine, the fuel oil is pumped into a heater to supply the heated fuel oil to the diesel engine, and excess fuel oil not consumed by the diesel engine is returned to the pressure accumulator via a pressure regulating valve, A connecting pipe through which fuel oil and/or vapor in the pressure accumulator flows is provided at a predetermined position on the side of the pressure accumulator, and the pre-booster pump is connected to the connecting pipe, and the pre-booster pump is connected to the connecting pipe. A fuel oil return pipe line for returning fuel oil and vapor to the fuel oil tank is connected to a portion of the connecting pipe above the connection position of the booster pump, and the pressure regulating valve is attached to this fuel oil return pipe. A fuel oil circulation circuit is constructed that passes through a tank, a pre-booster pump, a connecting pipe, and a pressure regulating valve, and vapor in excess of the required amount accumulated in the pressure accumulator is discharged into the connecting pipe, and this vapor is transferred from the pre-booster pump to the connected pipe. This is a fuel oil supply device for a diesel engine, which is characterized in that the fuel oil sent to the pressure accumulator is returned to the fuel oil tank through a pressure regulating valve along with the excess fuel oil, which is used to prevent excess fuel oil from being accumulated in the pressure accumulator. The vapor is returned to the fuel oil tank together with the excess fuel oil discharged from the prebooster pump without using a vapor discharge device, and the excess fuel oil is used to cool the vapor and condense it. Therefore, it is possible to provide a fuel oil supply device that is safe and has less dirt, without the risk of the vapor and the fuel oil accompanying it spouting out.

[Brief explanation of the drawing]

Fig. 1 is a fuel oil piping system diagram of a fuel oil supply system for a diesel engine according to one embodiment of the present invention, Fig. 2 is a diagram corresponding to Fig. 1 of a fuel oil supply system according to another embodiment, and Fig. 3 4 is a side sectional view of a pressure accumulator part that can be used in the embodiment shown in FIG. 1 or 2, and FIG. 5 is a system diagram of a conventional fuel oil supply system for diesel engines. . Explanation of symbols, 1...Pre-booster pump, 3...
...Pressure accumulator, 3a... Pressure accumulator neck section, 4... Fuel oil return pipe, 5... Fuel oil tank, 6'... Pressure regulating valve, 6a... Valve seat, 7... Booster pump, 8...
... Heater, 9 ... Fuel oil supply pipe, 10 ... Diesel engine, 11 ... Pressure regulating valve, 12 ... Vapor discharge pipe, 13 ... Vapor discharge pipe, 14 ... Oil supply pipe, 15 ... Vapor Communication pipe, 15a, 15b...
Connection part, 15c... Vapor connecting pipe neck part, 16...
Oil distribution pipe, 17...vapor separation pipe, 18...flow meter, L...oil level.

Claims (1)

[Scope of Claim for Utility Model Registration] The fuel oil in the fuel oil tank is maintained at a constant pressure by a pressure regulating valve and sent to a pressure accumulator by a pre-booster pump, and the fuel oil discharged from the pressure accumulator is transferred to a heater by a booster pump. In the fuel oil supply system for a diesel engine, which supplies heated fuel oil to the diesel engine, and returns excess fuel oil that is not consumed by the diesel engine to the pressure accumulator via a pressure regulating valve, A connecting pipe through which fuel oil and/or vapor in the pressure accumulator flows is provided protrudingly at a predetermined position, and the pre-booster pump is connected to the connecting pipe, and the connection position of the pre-booster pump with respect to the connecting pipe is A fuel oil return pipe for returning fuel oil and vapor to the fuel oil tank is connected to the upper connecting pipe, the pressure regulating valve is attached to the fuel oil return pipe, and the fuel oil tank, prebooster pump, A fuel oil circulation circuit is configured via a connecting pipe and a pressure regulating valve, and vapor in excess of the required amount accumulated in the pressure accumulator is discharged to the connecting pipe, and this vapor is directed from the pre-booster pump to the pressure accumulator. 1. A fuel oil supply device for a diesel engine, characterized in that the fuel oil is returned to a fuel oil tank through a pressure regulating valve along with surplus fuel oil fed into the fuel oil tank.