JP4824051B2 - Construction equipment fuel supply system - Google Patents

Description

  The present invention relates to a fuel supply device for a construction machine, and more particularly to a fuel supply device for a construction machine that can maintain the properties of the fuel.

  A construction machine is equipped with a diesel engine as a power source. In order to store and supply fuel to the engine, a fuel storage tank is provided with a main tank and a sub tank. Fuel is supplied from the main tank to the sub tank in a necessary amount, and the fuel stored in the sub tank is supplied to the engine. (For example, refer to Patent Document 1).

JP 2003-269273 A

  In the fuel supply apparatus for a construction machine described above, a fuel filter is provided in the supply pipe for the fuel sucked by the fuel injection pump mounted on the engine, mainly for removing contaminants and mixing water. In general, a method for improving the properties of the fuel while suppressing the fuel is used. The fuel filter captures pollutants and wax mixed in the fuel, but when the pollutants and wax are trapped, the oil flow resistance rises and reaches the specified oil flow resistance. .

  The life of a fuel filter greatly depends on the properties of the fuel and the operating status / load status of the machine.Therefore, the replacement interval is operated with a certain margin. Continuing to use in a clogged state may cause trouble or failure in the fuel system due to cavitation of the fuel pump due to a decrease in the fuel suction pressure or outflow of contaminants due to poor filtration. .

  On the other hand, as a response to exhaust gas regulations currently being promoted in various countries, many methods for increasing the fuel injection pressure to the engine are taken. As the fuel injection pressure rises, the gap between the injection pump and the nozzle has become narrower than before, so the fuel contamination and clogging regulations have become stricter. In order to cope with this, it is necessary to increase the filtration accuracy and the filtration area of the fuel filter (increase the number of filters), and the properties of the fuel to be added more strictly than before, and the machine body Many filters have been installed.

  However, it does not hinder the operation in regions and countries where fuels with good properties can be used, but it is difficult to obtain good fuels, and there are problems with the fuel management method. When the construction machine is operated in this way, the life of the fuel filter may be extremely deteriorated. When the life of the fuel filter is deteriorated, the replacement interval is shortened, which affects the machine operating rate. In this case, the investigation and analysis are performed, further filter addition and filtration improvement measures are taken, and the replacement interval of the fuel filter is extended.

  However, since the fuel is sucked in by the pump equipped with the engine, it is not possible to increase the number of filters below a predetermined lower limit value, and it is often impossible to secure a normal fuel filter replacement interval.

  The present invention has been made based on the above-described matters, and an object thereof is to provide a fuel supply device for a construction machine that can stably set the life of a standard filter without depending on the properties of the fuel. .

  To achieve the above object, a first invention provides a fuel supply device for a construction machine, comprising a fuel subtank for supplying fuel to an engine fuel injection device and a fuel main tank for supplying fuel to the fuel subtank. A fuel supply pipe connecting an engine fuel pump and the fuel main tank, having a standard filter and a check valve, a fuel return pipe for returning return fuel from the engine to the fuel main tank, and A fuel branch pipe branched from a fuel supply pipe and connected to the fuel sub tank, a fuel sub pump provided in the fuel branch pipe, an extension filter provided on the suction side of the fuel sub pump in the fuel branch pipe, A fuel sub-supply pipe connecting the fuel sub-pump between the standard filter and the check valve in the fuel supply pipe, and a check valve; Characterized by comprising a fuel sub-return pipe connecting the serial fuel return pipe and the fuel sub-pump.

  According to a second aspect of the present invention, in the first aspect, the fuel sub pipe having a part of the fuel supply pipe, the fuel sub tank, the fuel sub pump, the additional filter, the fuel sub supply pipe, and the check valve. The return pipe is made into a kit, and these can be exchangeably connected to the fuel supply pipe and the fuel return pipe.

  Furthermore, the third invention is characterized in that, in the second invention, the fuel sub-pump and the additional filter are unitized.

  In addition, a fourth invention is characterized in that, in any one of the first to third inventions, the extension filter is set to have a replacement interval longer than that of the standard fuel filter.

  According to the present invention, the life of a standard filter can be set stably without depending on the properties of the fuel, so that it is possible to prevent a shortened life of a standard fuel filter equipped in advance. As a result, the operation stoppage of the construction machine due to the deterioration of the performance of the fuel filter can be suppressed as much as possible. In addition, the fuel supply corresponding to the exhaust gas regulations can be performed for a long time, and the reliability of the construction machine is improved.

Embodiments of a fuel supply device for a construction machine according to the present invention will be described below with reference to the drawings.
1 to 3 show an embodiment of a fuel supply apparatus for a construction machine according to the present invention. FIG. 1 shows a circuit configuration of an embodiment of a fuel supply apparatus for a construction machine according to the present invention. 2 and 3 show the fuel supply operation of the embodiment of the fuel supply device for the construction machine of the present invention shown in FIG. In FIG. 1, reference numeral 1 denotes an engine of a construction machine. The engine 1 has a fuel injection device (not shown). A fuel pump 2 for supplying fuel to the fuel injection device is connected to the fuel injection device. The fuel pump 2 is connected to the bottom side of the fuel main tank 6 by a fuel supply pipe 5 having a standard filter 3 and a check valve 4.

  The surplus fuel in the fuel injection device is returned to the fuel main tank 6 by the fuel return pipe 7. The discharge end of the fuel return pipe 7 is connected to the fuel main tank 6 so as to be above the liquid level in the fuel main tank 6 so that the tank head of the fuel main tank 6 does not act. The fuel return pipe 7 is provided with a fuel cooler 8 for preventing an increase in the temperature of the fuel for complying with exhaust gas regulations, and a low pressure relief valve 9 for protecting the fuel cooler 8 when the fuel temperature is low.

  The fuel sub tank 10 is placed separately from the fuel main tank 6. The upstream side of the check valve 4 in the fuel supply pipe 5 and the fuel sub tank 10 are provided with a fuel supply branch pipe 11 that connects them. The fuel supply branch pipe 11 is provided with a fuel sub pump 12 that supplies the fuel in the fuel main tank 6 to the fuel sub tank 10 and an additional filter 13 that is located on the suction side of the fuel sub pump 12. The fuel sub-pump 12 has a discharge flow rate equal to or greater than the maximum consumption fuel of the engine. The extension filter 13 has a replacement interval longer than that of the standard fuel filter 3.

  In order to supply the fuel in the fuel sub-tank 10 to the fuel injection device of the engine 1, the fuel sub-tank 10 and the pipe line between the standard filter 3 and the check valve 4 in the fuel supply pipe 5 are connected by the fuel sub-supply pipe 14. It is connected. Further, a fuel sub return pipe 16 branched from the fuel return pipe 7 and having a check valve 15 is connected to the fuel sub tank 10.

Next, operation | movement of one Embodiment of the fuel supply apparatus of the construction machine of this invention mentioned above is demonstrated using FIG.2 and FIG.3.
FIG. 2 shows a fuel supply state of an embodiment of the fuel supply device for a construction machine according to the present invention, in which the fuel flow is indicated by a bold line.
By driving the fuel sub-pump 12, the fuel in the fuel main tank 6 is supplied to the fuel sub-tank 10 after the foreign matter in the fuel is removed by the extension filter 13 through the fuel supply branch pipe 11. Since the fuel sent to the fuel sub tank 10 is more than the fuel consumed by the engine, the pressure in the fuel sub tank 10 is increased, but the check valve 4 provided in the fuel supply pipe 5 sucks into the suction side of the fuel supply branch pipe 11. It will not be. Excess fuel in the fuel sub tank 10 is returned to the fuel main tank 6 by the fuel sub return pipe 16 and the fuel return pipe 7.

  Next, when the fuel pump 2 is driven, the fuel accumulated in the fuel sub-tank 10 is supplied to the fuel injection device via the fuel supply pipe 5 and the standard filter 3. Therefore, since the fuel supplied to the standard filter 3 is filtered by the extension filter 14, the life of the standard filter 3 can be stabilized.

  Fuel other than that consumed by the engine 1 is returned to the fuel main tank 6 through the fuel return pipe 7 and the fuel cooler 8.

  As described above, the fuel other than that consumed by the engine 1, that is, the surplus fuel in the fuel sub-tank 10 and the fuel that has not been consumed by the engine 1 are filtered in advance by the additional filter 13. Since the fuel is continuously circulated to the main tank 6, the quality of the fuel is improved as the fuel supply operation is continued. As a result, it is possible to suppress the deterioration of the standard filter 3 and extend its life.

  Further, when the discharge amount from the fuel sub pump 12 becomes insufficient for some reason while the fuel pump 2 is being driven, the pressure in the fuel sub tank 10 decreases, and the check valve 4 does not work. As a result, as shown by the thick line in FIG. 3, the fuel in the fuel main tank 6 is supplied to the fuel pump 2 through the fuel supply pipe 5 having the standard filter 3 and the check valve 4. The fuel supply can cope with the problem of the fuel supply on the 13th side.

  Further, according to the above-described embodiment of the present invention, it is not necessary to increase the number of filters 13 so that the fuel suction pressure does not become a specified value or less, and the number, capacity, etc. of the additional filters 13 can be freely adjusted according to the purpose of use. Can be increased or decreased.

  In the above-described embodiment, a part of the fuel supply pipe 5 having the check valve 4 in the dotted frame shown in FIGS. 1 to 3, the fuel sub tank 10, the fuel sub pump 12, the extension filter 13, and the fuel sub supply pipe 14 and the fuel sub return pipe 16 having the check valve 15 can be made into a kit and can be configured to be exchanged and connected to the fuel supply pipe 5 and the fuel return pipe 7.

  The fuel sub pump 12 and the extension filter 13 (two connected in parallel in this example are shown) are assembled in advance into the base 17 as a unit as shown in FIGS. It is also possible.

  If comprised in this way, when replacing | exchanging the fuel subtank 10, the fuel subpump 12, and the expansion filter 13, while the effort of the assembly can be saved, and the assembly is also possible for a short time, the fuel in construction machinery The supply device can be restored quickly.

  In the above-described embodiment, the fuel sub-pump 12 has a discharge flow rate that is equal to or higher than the maximum consumed fuel of the engine 1. Further, the replacement interval of the extension filter 13 is set larger than that of the standard filter 3. If replacement of the extension filter 13 is easy, the extension filter 13 can be shorter than the replacement interval of the standard filter 3.

  According to the embodiment of the present invention described above, the fuel property can be maintained by the standard filter 3 without depending on the fuel property to be used. Further, even when the system is abnormal, fuel can be supplied through the fuel supply pipe 5, so that the machine operation can be automatically continued and the operation can be maintained. Furthermore, stable fuel supply and standard filter performance can be maintained without adding a large system (electric control system).

  Further, a part of the fuel supply pipe 5 having the check valve 4 in the dotted frame shown in FIGS. 3 to 5, the fuel sub tank 10, the fuel sub pump 12, the additional filter 13, the fuel sub supply pipe 14, and the check valve 15. In addition to the effects described above, the initial cost of the standard main body can be suppressed and individual handling can be performed. In addition, by performing maintenance of the unit, the maintenance of the standard filter can be stably performed without depending on the fuel property.

It is a figure which shows the circuit structure of one Embodiment of the fuel supply apparatus of the construction machine of this invention. It is a figure which shows the fuel supply operation | movement of one Embodiment of the fuel supply apparatus of the construction machine of this invention shown in FIG. It is a figure which shows the fuel supply operation | movement at the time of abnormality of one Embodiment of the fuel supply apparatus of the construction machine of this invention shown in FIG. It is a front view which shows the unit structure of the fuel subpump and expansion filter which comprise one Embodiment of the fuel supply apparatus of the construction machine of this invention shown in FIG. FIG. 5 is a plan view of a unit structure of a fuel sub-pump and an additional filter constituting an embodiment of the fuel supply device for a construction machine according to the present invention shown in FIG.

Explanation of symbols

1 Engine 2 Fuel pump 3 Standard filter 4 Check valve 5 Fuel supply pipe 6 Fuel main tank 7 Fuel return pipe 8 Fuel cooler 9 Low pressure relief valve 10 Fuel sub tank 11 Fuel supply branch pipe 12 Fuel sub pump 13 Additional filter 14 Fuel sub supply pipe 15 Check valve 16 Fuel sub return pipe

Claims (4)

A fuel supply device for a construction machine comprising a fuel subtank for supplying fuel to a fuel injection device of an engine and a fuel main tank for supplying fuel to the fuel subtank,
A fuel supply pipe connecting an engine fuel pump and the fuel main tank, and having a standard filter and a check valve;
A fuel return pipe for returning fuel from the engine to the fuel main tank;
A fuel branch pipe branched from the fuel supply pipe and connected to the fuel sub tank;
A fuel sub-pump provided in the fuel branch pipe;
An additional filter provided on the suction side of the fuel sub-pump in the fuel branch pipe;
A fuel sub supply pipe connecting the standard filter and the check valve in the fuel supply pipe, and the fuel sub pump;
A fuel supply device for a construction machine, comprising a check valve and a fuel sub return pipe connecting the fuel return pipe and the fuel sub pump. The fuel supply device for a construction machine according to claim 1,
A part of the fuel supply pipe, the fuel sub-tank, the fuel sub-pump, the additional filter, the fuel sub-supply pipe, and the fuel sub return pipe having the check valve are made into a kit, and these are the fuel supply pipe and A fuel supply device for a construction machine, wherein the fuel return pipe can be exchanged and connected. The fuel supply device for a construction machine according to claim 2,
A fuel supply device for a construction machine, wherein the fuel sub-pump and the additional filter are unitized. The fuel supply device for a construction machine according to any one of claims 1 to 3,
A fuel supply device for a construction machine, wherein the extension filter is set to have a replacement interval longer than that of the standard fuel filter.

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