JP4334785B2 - Diesel engine fuel supply system - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a fuel supply device for a diesel engine that suppresses the wear of an injection pump even when fuel with low lubricity is used.
[0002]
[Prior art]
A fuel supply device for a diesel engine includes a governor and a fuel injection pump. There are two types of governors: mecha governor and electronic governor. The fuel injection pump includes a row injection pump, a distribution injection pump, and a common rail injection pump. A fuel supply device of the following type is known by combining these governors and injection pumps.
[0003]
(1) Mechanical governor and row type injection pump (2) Mechanical governor and distribution type injection pump (3) Electronic governor and row type injection pump (4) Electronic governor and distribution type injection pump (5) Electronic governor and common rail type injection pump ]
In recent years, environmentally friendly low-sulfur diesel oil has been used as a fuel for diesel engines. Since this low-sulfur diesel oil has lower lubricity than conventional diesel oil, a lubricant is added in advance in Japan. In recent years, the pressure of fuel supplied to diesel engines has been increasing. Along with this, when low sulfur light oil to which no lubricant is added is used, there is a risk that the movable part of the injection pump will be seized. In particular, such a problem becomes apparent in a distribution type injection pump and a common rail type injection pump that require a higher fuel pressure. Similar problems occur when kerosene or the like is used in addition to light oil.
[0005]
An object of the present invention is to provide a fuel supply device for a diesel engine that does not impair the durability of an injection pump even if light oil or kerosene having low lubricity is used.
[0006]
[Means for Solving the Problems]
(1) A fuel supply device for a diesel engine according to the present invention includes a fuel tank in which fuel for the diesel engine is stored, an injection pump for supplying fuel from the fuel tank to the diesel engine at a high pressure, and lubricity of the fuel. It includes a lubricity enhancing agent tank for storing a lubricity improver to improve, and adding means for adding the lubricity improver before Symbol lubricity enhancing agent tank in accordance with the state of the device to the fuel, the additive means An open / close valve connected to the lubricity improver tank to control the addition of the lubricity improver to the fuel, a control means for controlling the opening / closing of the open / close valve according to the state of the device, and the control means to When the open / close valve is opened, the amount of the lubricity improver added to the fuel through the open / close valve is determined regardless of the remaining amount of the lubricity improver in the lubricity improver tank. Characterized in that it comprises a control pressure compensating valve.
(2) According to a second aspect of the present invention, in the fuel supply device for a diesel engine according to the first aspect, when the control means detects that the diesel engine is in operation, the lubricity improver is added to the fuel. The on-off valve is controlled.
(3) The invention of claim 3 is the fuel supply device for a diesel engine according to claim 2, wherein a mixing chamber for adding a lubricity improver to the fuel is provided in the fuel passage via the on-off valve.
(4) According to a fourth aspect of the present invention, in the fuel supply device for a diesel engine according to the second aspect, the on-off valve is connected to the fuel tank, and a lubricity improver is added to the fuel in the fuel tank; To do.
(5) The invention of claim 5 is the fuel supply device for a diesel engine according to any one of claims 1 to 4, wherein the sensor outputs a signal corresponding to the amount of the lubricity improver in the lubricity improver tank; And an alarm means for alarming when a signal indicating that the amount of the lubricity improver is equal to or less than a predetermined amount is output from the sensor.
[0007]
Embodiment
-First embodiment-
A first embodiment of a fuel supply device for a diesel engine according to the present invention will be described with reference to FIGS. In FIG. 1, fuel is supplied from a fuel supply device 100 to a diesel engine 70. The fuel supply device 100 includes a fuel tank 1. The fuel tank 1 stores fuel, for example, low sulfur gas oil. The fuel in the tank 1 is supplied to the fuel injection pump 4 by the feed pump 2. The fuel flowing out of the tank 1 flows from the pipe line 21 to the water separator 22. The fuel from which water has been separated by the water separator 22 flows through the pipe line 23 to the feed pump 2 and the priming pump 3, and further flows from the pipe line 24 into the fuel filter 25. The fuel from which dust has been removed by the filter 25 flows into the fuel injection pump 4 through the pipe line 26. The injection pump 4 compresses the supplied fuel at a high pressure, and guides the supplied fuel to nozzles 72 installed in each cylinder of the diesel engine by a pipe line 27 (only one cylinder is shown). High pressure compressed fuel is injected from the nozzle 72 into each cylinder. The fuel that could not be injected from the nozzle 72 returns from the leakage pipe 28 to the fuel tank 1. On the other hand, surplus fuel in the injection pump 4 returns to the fuel tank 1 from the pipe line 29.
[0008]
In the fuel supply device 100 of the first embodiment, the lubricity improver is added from the lubricity improver addition device 50 to the fuel in the fuel tank 1 via the pipe line 52. As shown in FIG. 2, the lubricity improver adding device 50 includes a lubricity improver tank 51 for storing the lubricity improver and an electromagnetic on-off valve disposed in a pipe line 52 connected to the bottom surface of the tank 51. 53 and a controller 54. The controller 54 includes a CPU, its peripheral circuits, ROM, RAM, and the like. The controller 54 receives signals from various sensors that detect the operating state of the diesel engine, for example, an oil pressure switch 55. When the diesel engine 70 starts operation, engine lubricating oil is supplied to each part of the engine at a predetermined pressure, and the oil pressure switch 55 is turned on. The controller 54 determines from the signal from the oil pressure switch 55 that the diesel engine is in operation, and switches the electromagnetic on-off valve 53 to the open position a.
[0009]
The electromagnetic on-off valve 53 is switched between two positions, an open position A and a closed position B. When the electromagnetic on-off valve 53 is switched to the open position (a), the throttle 53a is interposed in the pipe line 52 connecting the lubricity improver tank 51 and the fuel tank 1. Therefore, the lubricity improver in the tank 51 flows into the pipe line 52 by the head pressure and is added to the fuel in the fuel tank 51. The lubricity improver is, for example, an organic oxide, and a concentration of, for example, 50 to 120 ppm is sufficient. There is no adverse effect up to a concentration of about 200 to 300 ppm. For example, when the fuel tank 1 has a capacity of 200 to 300 liters, if 20 liters of the lubricity improver is stored in the lubricity improver tank 51, the lubricity improver is used for several tens of months. There is no need to replenish.
[0010]
In the lubricity improver supply device 50 of FIG. 2, when the amount of the lubricity improver in the lubricity improver tank 51 decreases, the head pressure also decreases and the lubricity improves through the throttle 53 a of the on-off valve 53. The amount of agent also varies. Therefore, as shown in FIG. 3, a pressure compensation flow rate adjusting valve 56 is provided in the pipe line 52 between the electromagnetic opening / closing valve 53 and the fuel tank 1. The pressure compensation flow rate adjusting valve 56 is used when the electromagnetic on-off valve 53 is switched to the open position a even when the storage amount of the lubricity improver in the lubricity improver tank 51 changes and the head pressure fluctuates. The flow rate through the throttle is not changed.
[0011]
FIG. 4 shows a case where a relay 57 is used in place of the controller 54 mainly composed of a CPU. When the oil pressure switch 55 is closed, a current flows from the power source 59A to the relay coil, and the relay contact is closed. When the relay contact is closed, a current flows from the power source 59B to the solenoid of the electromagnetic on-off valve 53, and the electromagnetic on-off valve 53 is switched to the A position.
[0012]
FIG. 5 uses a hydraulic pilot type on-off valve 153 instead of the electromagnetic on-off valve 53. For example, when the diesel engine 70 is started by operating the starter switch 71, the operation system hydraulic pump 61 starts rotating. The hydraulic pump 61 supplies pilot oil to the pressure reducing valves 63 a and 63 b of the pilot operating device 63 via the pipeline 62. The pipe line 62 is connected to the pilot port of the pilot type on-off valve 153. Therefore, when the diesel engine 70 is started, the pilot type on-off valve 153 is switched to the open position a.
[0013]
Instead of the discharge pressure of the operation system hydraulic pump 61, the on-off valve 153 may be switched by the lubricating oil pressure of the diesel engine 70 or the discharge water pressure of the water pump of the engine cooling system.
[0014]
Instead of the discharge pressure of the operation system hydraulic pump 61, a lubricity improver is mixed into the fuel in conjunction with the operation of the operating device 63, for example, a hydraulic excavator, on which the diesel engine 70 is mounted. Also good. In FIG. 5, when the pressure reducing valve 63 a or 63 b of the pilot operating device is operated, pressure is generated in the pilot line 64. This pressure is guided to the pressure switch 66 by the shuttle valve 65, and the pressure switch 65 is turned on. A signal from the pressure sensor 66 is input to the controller 54 shown in FIG. When the controller 54 receives the signal indicating that the pressure switch 66 is ON, the controller 54 determines that the diesel engine is in operation and switches the electromagnetic on-off valve 53 to the open position A.
[0015]
The electromagnetic on-off valve 53 may be switched by detecting that the starter switch of the diesel engine is operated to the on position. In this case, the diesel engine need not be in operation. The electromagnetic on-off valve 53 may be switched by detecting that the operation of the diesel engine has ended. For example, it may be detected that the starter switch is switched from the on position to the off position. Alternatively, the electromagnetic on-off valve 53 may be switched by detecting the presence or absence of rotation of the rotating portion of the diesel engine, such as rotation of the crankshaft. The electromagnetic on-off valve 53 may be switched by detecting the terminal voltage of the alternator. If the voltage is equal to or higher than the predetermined voltage, the diesel engine is in operation and the electromagnetic on-off valve 53 is switched to the open position.
[0016]
-Second Embodiment-
FIG. 6 shows a fuel supply device for a diesel engine according to the second embodiment. The fuel supply device 100A of the second embodiment is provided with a mixing chamber 81 in the fuel passage 21 as shown in an enlarged view in FIG. 7, and the lubricity improver is added to the mixing chamber 81 from the lubricity improver adding device 50. Is added. As the lubricity improver adding device 50, various devices shown in FIGS. 2 to 5 can be used. However, it is not possible to employ a method of detecting that the operation of the diesel engine has been completed and switching the electromagnetic on-off valve 53.
[0017]
In the fuel supply device 100A of the second embodiment, the diesel engine 70 is started and fuel flows into the injection pump 4 from the pipelines 21, 23, 24, and 26 by the feed pump 3. Therefore, the fuel pressure in the mixing chamber 81 provided in the fuel passage 21 is a negative pressure. When the on-off valve 53 is opened in synchronization with the start of the diesel engine 70, the lubricity improver is added from the lubricity improver addition device 50 to the fuel in the mixing chamber 81. Since the fuel flows through the pipe 21 and the like at a predetermined flow rate, the added lubricity improver is sufficiently diffused before reaching the injection pump 4.
[0018]
As shown in FIG. 8, the mixing chamber 81 can be installed in various places 82-87. Between the separator 22 and the feed pump 3, between the fuel filter 25 and the injection pump 4, in the return line from the injection pump 4, between the nozzle 72 and the linkage valve 28A, between the linkage valve 28A and the fuel tank 1. Any location, such as between, may be used. The inside of the separator 22 may be a mixing chamber. In this case, the lubricity improver addition device 50 is connected to the separator 22.
[0019]
By providing such a mixing chamber and adding a lubricity improver to the mixing chamber, it is possible to add only the amount necessary for the combustion of the diesel engine. For example, a smaller amount is required than when the lubricity improver is added directly to the fuel tank described in the first embodiment.
[0020]
FIG. 9 is to notify that the amount of the lubricity improver in the lubricity improver tank 51 has become a predetermined amount or less. A sensor 91 is provided in the lubricity improver tank 51. When the amount of the lubricity improver is equal to or less than a predetermined amount, the sensor 91 outputs a signal indicating that the amount is less than the predetermined amount. The alarm buzzer 92 is sounded by this signal. You may alert | report by an audio | voice. Alternatively, characters may be displayed on the display monitor. The operator replenishes the lubricity improver tank 51 with the lubricity improver based on such an alarm.
[0021]
10 and 11 show an embodiment in which the electromagnetic on-off valve 53 is driven in accordance with the fuel in the fuel tank 1. In FIG. 10, the float fuel sensor 110 rotates according to the fuel water level in the fuel tank 1 and outputs a signal corresponding to the amount of fuel. This detection signal is input to the controller 54. The controller 54 determines that the amount of fuel detected by the fuel sensor 110 has increased due to refueling, and adds a lubricity improver to the fuel tank 1. The addition amount of the lubricity improver increases in proportion to the increase in fuel.
[0022]
FIG. 11 is a flowchart showing a program for adding a lubricity improver according to the fuel increase amount. The program is executed by the controller 54. In step S <b> 1, the controller 54 determines whether or not fuel has been replenished based on a signal from the fuel sensor 110. Based on the signal from the fuel sensor 110, the fuel increase is monitored, and it can be determined that the fuel supply is performed when the increase is stopped after the start of the increase. If fuel supply is determined, the process proceeds to step S2. In step S2, the amount of fuel replenished by a signal from the fuel sensor 110 is calculated. In step S3, the valve opening time corresponding to the amount of fuel replenished is calculated from the table. In step S4, the electromagnetic on-off valve 53 is opened for the calculated time.
[0023]
According to the embodiment described with reference to FIGS. 10 and 11, an amount of the lubricity improver commensurate with the fuel supply is added from the lubricity improver tank 51 to the fuel tank 1. Therefore, the lubricity improver can be added to the fuel without excess or deficiency. Further, not only the operation state of the diesel engine but also information related to fuel consumption can be used as an index for adding the lubricity improver.
[0024]
The diesel engine fuel supply apparatus described above is used in various construction machines. For example, the above-described hydraulic excavator, hydraulic crawler crane, hydraulic foundation machine, large dump truck for mining, wheel loader, soil conditioner, crushing device, and the like. The fuel supply device is not limited to the above embodiment. Any device may be used as long as it detects the operation state of the diesel engine, the operation state of the construction machine, or the state of various devices constituting the construction machine and adds the lubricity improver to the fuel. For example, a flow control valve may be used instead of the on-off valve. Alternatively, other valve means may be used as long as the addition of the lubricity improver to the fuel can be controlled. Furthermore, a method of adding a lubricity improver to the fuel by a pump or adding a lubricity improver to the fuel by a cylinder may be used.
[0025]
【The invention's effect】
According to the present invention, since the lubricity improver is added to the fuel according to the state of the equipment, the moving parts of the injection pump are worn even when fuel with low lubricity such as low sulfur gas oil or kerosene is used. The risk of doing so is reduced. Further, since the addition to the fuel is automatically performed according to the state of the equipment, there is no fear that the operator forgets to add the lubricity improver.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first embodiment of a fuel supply device for a diesel engine according to the present invention. FIG. 2 is a diagram showing details of the lubricity improver addition device of FIG. FIG. 4 is a circuit diagram when the controller is configured by a relay. FIG. 5 is a configuration diagram when the electromagnetic on-off valve is replaced by a pilot hydraulic on-off valve. FIG. 6 is a diesel engine according to the present invention. FIG. 7 is an enlarged view of the mixing chamber. FIG. 8 is a diagram for explaining the installation location of the mixing chamber. FIG. 9 is an improvement of lubricity in the lubricity improver tank. FIG. 10 is a diagram for explaining an embodiment in which an alarm is given according to the amount of the agent. FIG. 10 is a diagram for explaining an embodiment in which a lubricity improver is added according to the amount of fuel increase in the fuel tank. 11 is a flowchart for explaining the program in the embodiment of FIG. Chart DESCRIPTION OF SYMBOLS
1: Fuel tank 3: Feed pump 4: Fuel injection pump 50: Lubricant improver addition device 51: Lubricant improver tank 53: Electromagnetic on-off valve 54: Controller 55: Oil pressure switch 70: Diesel engine 100, 100A: Fuel Supply device 110: Fuel sensor

Claims (5)

A fuel tank for storing diesel engine fuel;
An injection pump for supplying fuel from the fuel tank to a diesel engine at a high pressure;
A lubricity improver tank for storing a lubricity improver that improves the lubricity of the fuel;
According to the state of the equipment, comprising an addition means for adding a lubricity improver from the lubrication improver tank to the fuel ,
The adding means is connected to the lubricity improver tank to control the addition of the lubricity improver to the fuel, and the control means for controlling the opening and closing of the open / close valve according to the state of the device ; Addition of the lubricity improver added to the fuel through the on / off valve when the on / off valve is opened by the control means, regardless of the remaining amount of the lubricity improver in the lubricity improver tank A fuel supply device for a diesel engine, comprising a pressure compensation valve that controls the amount to be quantitative . The fuel supply device for a diesel engine according to claim 1,
When the control means detects that the diesel engine is in operation, the control means switches the open / close valve to the open position so that the lubricity improver is added to the fuel. The fuel supply device for a diesel engine according to claim 2,
A fuel supply device for a diesel engine, wherein a mixing chamber for adding a lubricity improver to the fuel is provided in the fuel passage through the on-off valve . The fuel supply device for a diesel engine according to claim 2 ,
A fuel supply device for a diesel engine, wherein the on-off valve is connected to the fuel tank, and a lubricity improver is added to the fuel in the fuel tank . In the fuel supply apparatus of the diesel engine in any one of Claims 1-4,
A sensor that outputs a signal corresponding to the amount of the lubricity improver in the lubricity improver tank;
A fuel supply device for a diesel engine, comprising alarm means for warning when a signal indicating that the amount of the lubricity improver is equal to or less than a predetermined amount is output from the sensor .

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