JP3704345B1 - Fuel supply device - Google Patents

Abstract

The present invention relates to a fuel supply device that switches and supplies a plurality of liquid fuels to a combustion heat source such as a heat engine or a water heater boiler while stabilizing its output, and in particular, switches the fuel with a very simple configuration. Therefore, a fuel supply apparatus that can be easily maintained is provided.
A fuel injection device that supplies liquid fuel to an engine by suction action, a plurality of fuel supply lines that are connected in parallel to the fuel injection device and supply different types of liquid fuel, and these fuels Check valves 10 and 11 provided in the supply lines, respectively, for preventing the backflow of liquid fuel sucked by the fuel injection device, and fuel selection for selecting from which fuel supply line the liquid fuel is sucked by the fuel injection device Means.
[Selection] Figure 1

Description

  The present invention relates to a fuel supply device that switches and supplies a plurality of liquid fuels to a heat source of combustion such as a heat engine or a water heater boiler while stabilizing its output, and in particular, switches the fuel with a very simple configuration. The present invention relates to a fuel supply apparatus that can be performed and is therefore easy to maintain.

  Liquid engines are often used for various engines, heat engines such as gas turbines and steam turbines, and combustion heat sources such as boilers for hot water supply (hereinafter collectively referred to as “heat engines”). In these heat engines, the liquid fuel from the fuel tank is supplied to a fuel injection device including an injection pump and a nozzle by a fuel supply device.

  In recent years, there are many heat engines equipped with a fuel supply device that appropriately switches and supplies a plurality of types of liquid fuels including waste oil as measures for environmental problems and means for reducing fuel costs. However, in these heat engines, there is a problem that when the supply is switched from one fuel to another, the output fluctuates due to a temporary decrease in the amount of fuel supplied to the fuel injection device.

  Conventionally, as a fuel supply device that supplies a plurality of fuels to a heat engine, for example, a device disclosed in Patent Document 1 is known.

Patent Document 1 relates to a switching control method for switching the use of two types of fuel in a gas turbine plant. When switching between two fuels, the problem is that output (load) fluctuation due to temporary fuel shortage at the time of switching can be reduced and smooth fuel switching can be performed. In order to switch to the above, the corrected fuel flow rate is calculated by adding the deviation between the fuel flow rate setting value and the feedback signal of the actual fuel flow rate as a correction value to the fuel control signal input in advance. Further, when switching from one fuel to the other fuel, the state of the fuel on the side that is switched and used is monitored, and when the flow rate fluctuation of the fuel exceeds a predetermined value, the switching rate is slowed down, and the flow rate When the fluctuation becomes small, the switching rate is increased.
Japanese Patent Laid-Open No. 9-68056

  By the way, in the background art as described above, for example, in order to switch and supply a plurality of fuels while stabilizing the output of the heat engine, a complicated control means such as an ECU (electronic control unit) is used to control the fuel. Switching control was performed. In the fuel supply apparatus including the control means having such a complicated circuit configuration, not only repair work when abnormality occurs in the control means part but also normal maintenance work is technically difficult. At the same time, time and cost tend to be large.

  The present invention has been devised in view of the above-described conventional problems, and is a fuel supply device that switches and supplies a plurality of liquid fuels to a combustion heat source such as a heat engine or a water heater boiler while stabilizing its output. In particular, it is an object of the present invention to provide a fuel supply device that can perform fuel switching with a very simple configuration and is therefore easy to maintain.

A fuel supply device according to the present invention includes a fuel suction unit that supplies liquid fuel to a heat engine by suction, a plurality of fuel supply lines that are connected in parallel to the fuel suction unit and supply different types of liquid fuel, A check valve provided in each of these fuel supply lines to prevent backflow of liquid fuel sucked by the fuel suction means, and a fuel for selecting from which fuel supply line the liquid fuel is sucked by the fuel suction means Selecting means, and the fuel selecting means is provided between the check valve of each fuel supply line and the fuel suction means, and a merging section for joining these fuel supply lines, and at least one of the fuel supply It is characterized in that it is provided in the line so as to be positioned upstream of the check valve, and comprises a pressure feeding means for pumping liquid fuel .

  Further, at least one of the fuels flowing through the plurality of fuel supply lines is a low-grade and high-viscosity fuel, and the low-grade and high-viscosity fuel tank has an exhaust gas flowing through the exhaust system. The heat exchanger which heat-exchanges and heats is provided.

  The low-grade high-viscosity fuel is a regenerated oil.

Further, at least one of the fuel flowing through the plurality of fuel supply lines is a low-load fuel that is easily combusted even during a low-load operation of the heat engine, and after the operation of stopping the heat engine, Control means for selecting a fuel supply line for the low load fuel by the fuel selection means is provided.

  Further, the fuel suction means supplies liquid fuel to a combustion heat source such as a water heater boiler instead of the heat engine.

  The fuel supply device according to the present invention can switch and supply a plurality of liquid fuels with a very simple configuration while stabilizing the output of a heat source such as a heat engine or a hot water heater boiler, and therefore maintenance is also possible. It can be done easily.

Hereinafter, an embodiment of a fuel supply apparatus according to the present invention will be described in detail with reference to the accompanying drawings. As shown in FIG. 1, the fuel supply device 1 according to the present embodiment supplies a plurality of types of liquid fuel to a diesel engine 2 as a heat engine. In this embodiment, the diesel engine 2 is mounted on a vehicle and supplies power to the drive system of the vehicle.

  The fuel supply apparatus 1 basically includes fuel tanks 3 and 4 filled with liquid fuel, fuel supply lines 5 and 6 into which liquid fuel flows from the fuel tanks 3 and 4, and fuel supply lines 5 and 6, respectively. And a fuel injection device 9 that injects the liquid fuel flowing through the junction 7 into each cylinder 8 of the engine 2. The fuel injection device 9 has not only an injection function but also a pump function, and is a fuel suction means that always draws fuel in both fuel supply lines 5 and 6 through the junction 7 by suction. Further, in each fuel supply line 5, 6, reverse flow to prevent backflow of liquid fuel from the upstream side (fuel tanks 3, 4 side) to the strainers 12, 13, the maintenance valves 14, 15 and the junction 7 in order. Stop valves 10 and 11 are provided. The fuel tank 3 is filled with regenerated oil obtained by regenerating waste cooking oil such as tempura oil, and the fuel tank 4 is filled with light oil.

The fuel supply line 5 through which the regenerated oil flows is located upstream of the check valve 10 and the maintenance valve 14 and downstream of the strainer 12, and is a variable speed oil pump as a pressure feeding means for the regenerated oil. 16 is provided. The variable speed oil pump 16 and the above-described merging portion 7 constitute fuel selection means for selecting from which fuel supply lines 5 and 6 the liquid fuel is sucked by the fuel injection device 9 which is fuel suction means. The The variable speed oil feed pump 16 can freely adjust the pump operating speed, in other words, the pumping pressure for pushing the regenerated oil to the upstream side. When the pumping pressure is zero, the flow of the regenerated oil in the fuel supply line 5 is completely cut off. When the pumping pressure is sufficiently low, the pressure of the regenerated oil flowing through the downstream portion 5a (hereinafter referred to as the “downstream portion 5a”) of the variable speed oil pump 16 in the fuel supply line 5 causes the check valve 10 to open. When the pressure is lower than the valve pressure and the pumping pressure is sufficiently high, the pressure of the regenerated oil flowing through the downstream portion 5a is equal to or higher than the valve opening pressure of the check valve 10, and the suction action by the fuel injection means 9 is added. The pressure is set to be higher than the pressure of light oil flowing through the fuel supply line 6.

  A return line 17 for returning surplus fuel in the fuel injector 9 to the junction 7 is provided from the fuel injector 9 toward the junction 7 of the fuel supply lines 5 and 6. A check valve 18 is installed in the middle of the reflux line 17 to prevent the back flow of fuel.

  The engine 2 takes the air into the intake system 20 via the air cleaner 19 and sends it to each cylinder 8. A negative ion generator 21 is connected to the air cleaner 19. The negative ion generator 21 was developed by the inventor of the present application (see Japanese Patent Application Laid-Open No. 2003-130408), and mainly includes a main body portion 21a including a DC high-voltage power source and the like, and a coaxial shield wire 21b. It consists of. The tip of the coaxial shield wire 21b is cut out to expose the core wire, and this core wire forms an ionization needle. This ionization needle is connected to the inside of the casing inlet of the air cleaner 19 to negatively ionize oxygen molecules in the air cleaner 19 by corona discharge. The negatively ionized and activated oxygen improves the combustion speed of the engine 2 and reduces the unburned amount of fuel as compared with combustion by normal oxygen.

  Further, the intake system 20 of the engine 2 may be provided with a device for supplying a fuel for assisting the starting of the engine 2 at a low temperature or in a cold region, for example, a combustible gas such as liquefied petroleum gas.

  The exhaust system 22 that distributes the exhaust gas of the engine 2 mainly includes an exhaust pipe 23, a deodorization silencer 24 that reduces exhaust noise and exhaust gas odor, and an exhaust port 25. The exhaust pipe 23 is bifurcated at a position downstream of the deodorizing silencer 24. The exhaust gas passing through one exhaust pipe 23 a passes through the exhaust gas adjustment damper 26 and is then discharged from the exhaust port 25. The other exhaust pipe 23b is provided with a heat exchanger 27 at a portion in contact with the fuel tank 3 of the regenerated oil. The exhaust gas passing through the exhaust pipe 23b passes through the heat exchanger 27 and then passes through the exhaust port 25. Discharged.

  Since the reclaimed oil filled in the fuel tank 3 is a relatively low-grade and high-viscosity liquid fuel, in order to improve the fluidity in each part of the fuel supply device 1, it is necessary to reduce the viscosity as much as possible and supply it. There is. Therefore, the heat exchanger 27 provided in the fuel tank 3 is heated using the heat of the exhaust gas flowing through the exhaust pipe 23b.

  Furthermore, in this embodiment, the temperature sensor 28 is provided in the fuel tank 3, and the exhaust gas adjusting damper 26 and its damper controller 26a are provided in the exhaust pipe 23a. The temperature signal from the temperature sensor 28 is output to the control unit 29. The control unit 29 generates an opening signal for determining the opening of the exhaust gas adjustment damper 26 based on this temperature signal, and this opening signal is used for the exhaust gas adjustment. It outputs to the damper controller 26a of the damper 26. The damper controller 26a adjusts the opening of the exhaust gas adjustment damper 26 based on the opening signal. In the present embodiment, the opening degree of the exhaust gas adjustment damper 26 can be manually adjusted by operating the damper opening degree adjustment dial 31 of the control panel 30 provided on the front surface of the control unit 29.

  Further, in the middle of the fuel supply line 5, there is provided a regenerated oil circulation path 32 that branches from the downstream portion of the variable speed oil pump 16 so that the regenerated oil returns to the fuel tank 3. Since a part of the regenerated oil flowing in the fuel supply line 5 always flows and circulates in the regenerated oil circulation path 32, in addition to the heating action by the exhaust heat of the exhaust gas, the regenerated oil has a lower viscosity. Figured. An adjustment valve 33 is interposed in the regenerated oil circulation path 32. The adjustment valve 33 is set so that an appropriate amount of the regenerated oil pushed out by the variable speed oil pump 16 is circulated through the regenerated oil circulation path 32 by appropriately adjusting the opening thereof.

  The fuel tank 3 is provided with a regenerated oil reformer 34 filled with, for example, a germanium-based reforming catalyst, and maintains the molecular clusters of the regenerated oil in a fragmented state.

  Next, the operation of the fuel supply device 1 and the liquid fuel flowing through each part will be described in detail. During the operation of the engine 2, the fuel injection device 9 always draws the liquid fuel in the merging portion 7 by suction. Therefore, of the regenerated oil flowing through the fuel supply line 5 and the light oil flowing through the fuel supply line 6, the liquid fuel that flows into the junction 7 is eventually selected as a fuel, and is sucked into the fuel injection device 9, Further, it is burned in the cylinder 8 of the engine 2.

  By the way, the variable speed oil pump 16 is automatically adjusted by the control unit 29 as follows. That is, the variable speed oil feed pump 16 starts to operate when the engine 2 and the vehicle equipped with the engine 2 are started, and when the vehicle travels at a low speed, for example, the rotational speed of the engine 2 is up to 1200 rpm or the vehicle travel speed is 30 km. When the engine 2 has a low load, the engine 2 operates at a low pressure. At this low pressure supply pressure, the pressure of the regenerated oil flowing in the downstream portion 5 a of the fuel supply line 5 is set to be lower than the valve opening pressure of the check valve 10.

  Accordingly, when the vehicle travels at a low speed, the light oil flowing through the fuel supply line 6 is sucked into the fuel injection means 9. That is, light oil is exclusively supplied to the junction 7, the fuel injection device 9, and the cylinder 8. Thus, when the vehicle equipped with the engine 2 travels at a low speed (when the engine 2 is under a low load), the light oil is selected, and the cylinder 8 is exclusively burned with the light oil.

  When the vehicle equipped with the engine 2 is traveling at a high speed, in the above example, when the engine 2 is at a high load, such as the rotational speed of the engine 2 is 1200 rpm or higher, or the vehicle traveling speed is 30 km or higher, the variable speed oil feed pump 16 is Operates with high feed pressure. With this high pressure feed pressure, the pressure of the regenerated oil flowing in the downstream portion 5a of the fuel supply line 5 is equal to or higher than the valve opening pressure of the check valve 10, and the suction action of the fuel injection means 9 is added to the fuel supply line. 6 is set to be higher than the pressure of the light oil flowing through the fuel tank 6.

  Therefore, when the vehicle travels at a high speed, the pressure of the regenerated oil flowing through the downstream portion 5 a becomes higher than the pressure of the light oil flowing through the fuel supply line 6. As a result, in the front portion 5b of the joining portion, the flow of light oil in the front portion 6a of the joining portion is blocked, and the regenerated oil flows into the joining portion 7. FIG. 2 is an enlarged view showing the vicinity of the junction 7 in such a state. Accordingly, the regenerated oil is supplied exclusively to the junction 7, the fuel injection device 9, and the cylinder 8. Thus, when the vehicle equipped with the engine 2 travels at a high speed (when the engine 2 is highly loaded), the regenerated oil is selected, and the cylinder 8 exclusively burns the regenerated oil. At this time, since the check valve 11 is provided in the fuel supply line 6, the regenerated oil does not flow into the fuel tank 4 side.

  Furthermore, in the present embodiment, a vehicle driver or the like can manually switch between light oil and recycled oil. The driver supplies the cylinder 8 by operating the fuel changeover switch 36 provided on the control panel 30 while viewing the display of the engine tachometer 35 provided on the control panel 30 on the front surface of the control unit 29. Switch liquid fuel. Specifically, by operating the fuel changeover switch 36, the pumping pressure of the variable speed oil pump 16 is switched between a low pressure and a high pressure, and the liquid flowing into the merging section 7 as in the case of the automatic switching described above. A fuel is selected. A vehicle speedometer may be provided in place of the engine tachometer 35, and the switching operation may be performed while referring to the display.

In the fuel supply device 1 of the present embodiment, as described above, the liquid fuel to be supplied to the merging portion 7 is only selected by causing a difference in the fluid pressure between the regenerated oil and the light oil. During the operation of 2, the flow of both liquid fuels is not interrupted mechanically or electrically at any time. As the variable speed oil pump 16 is switched, the regenerated oil flows into the front portion 5b of the joining portion due to the suction action of the fuel injection means 9 and the pressure of the variable speed oil pump 16, and flows into the front portion 6a of the joining portion. The gas oil flows in by the suction action of the fuel injection means 9, and any liquid fuel is always supplied to the junction 7, the fuel injection means 9, and the cylinder 8 without interruption.

In particular, when the vehicle accelerates rapidly and the fuel consumption in the engine 2 increases rapidly in a short time, the negative pressure = suction action by the fuel injection device 9 temporarily increases rapidly. When the suction action is sufficiently large, the regenerated oil flows into the merging portion 7 through the front portion 5a of the merging portion and the light oil flows through the front portion 6a of the merging portion. That is, (1) Recycled oil is added in addition to diesel oil when suddenly accelerating during low-speed traveling due to diesel oil burning, and (2) Recycled oil when suddenly accelerating during high-speed traveling due to solely burning recycled oil In addition, light oil is smoothly supplied to the junction 7 and the fuel injection device 9. The case of (2) will be described in detail. For example, when the variable speed oil pump 16 is operated in two stages of low pressure and high pressure, the supply of light oil is generated by the amount that cannot be covered by the pressure of the regenerated oil by high pressure operation. Alternatively, when the variable speed oil pump 16 is operated in multiple stages, supply of light oil that cannot be covered during the operation delay period of the variable speed oil pump 16 occurs.

Further, particularly in a cold region, it is preferable that light oil is supplied from the fuel supply line 6 when the engine 2 is started, and the light oil is exclusively burned. This is because the regenerated oil is not sufficiently heated by exhaust heat immediately after start-up and has a high viscosity, so that the flowability in each part of the fuel supply device 1 is not good. However, for example, if the driver suddenly stops the vehicle and then immediately removes the key and stops the engine 2 suddenly, switching from regenerated oil at high speed rotation to light oil at low speed rotation is not performed reliably. If the engine 2 stops, the regenerated oil may remain selected at the next start. Therefore, in this embodiment, a control means (not shown) is provided, and after the engine 2 is stopped, control is performed so that the oil is surely switched to light oil and prepared for the next start. Specifically, immediately after the vehicle driver or the like turns off the switch, the engine 2 is not stopped, but is rotated at a sufficiently low speed (for example, 600 to 700 rpm) for a certain time and then stopped. As this control means, a generally known turbo timer or the like can be used.

  Further, in the above embodiment, the variable speed oil pump 16 is provided only in the fuel supply line 5 and the liquid fuel to be supplied is switched by adjusting only the pressure of the regenerated oil. The fuel supply line 6 may also be supplementarily provided with a second variable speed oil pump (not shown). In that case, the variable speed oil pump 16 is stopped at the time of low speed running, the second variable speed oil pump is operated, and the second variable speed oil pump is stopped at the time of high speed running, The variable speed oil pump 16 is operated. As a result, as in the case of the above embodiment, it is possible to generate a relative pumping pressure difference between the regenerated oil in the fuel supply line 5 and the light oil in the fuel supply line 6, and the junction 7 and the fuel injection The liquid fuel supplied to the device 9 will be switched.

  As described above, in the fuel supply device 1 of the present embodiment, the merging section can be easily achieved by simply adjusting the pumping pressure of the variable speed oil pump 16 provided in one fuel supply line 5. 7. Liquid fuel supplied to the fuel injection device 9 and the cylinder 8 can be selected.

  Further, when such fuel switching is performed, the flow of the liquid fuel in the fuel supply lines 5 and 6 is not mechanically or electrically interrupted, so that regenerated oil and light oil are supplied to the junction 7 and the fuel injection device 9. One of these is always supplied without interruption. Therefore, the output of the engine 2 is always kept stable without being temporarily reduced.

  In particular, when the fuel consumption in the engine 2 suddenly increases in a short time and the suction action by the fuel injection device 9 increases rapidly, the front portions 5a, 6a of the fuel supply lines 5, 6 are combined. Therefore, it is possible to prevent both the regenerated oil and the light oil from being supplied promptly, thereby causing a temporary shortage of fuel in the fuel injection device 9 and a temporary decrease in the output of the engine 2.

Further, the control unit 29 has a very simple configuration in which a signal of the rotational speed of the engine 2 or the vehicle speed is inputted and only a signal for determining the pressure of the variable speed oil pump 16 is output based on the signal. Is. Unlike an electronic control device having a complicated circuit, this is a highly reliable control means with a low possibility of occurrence of a failure, and is easy to repair even if a failure occurs.

  In short, in the fuel supply device 1 of the present embodiment, the liquid fuel can be switched while the output of the engine 2 is stabilized with a very simple configuration, and the maintenance is also very easy. It is.

  In the present embodiment, a heat exchanger 27 that heats the regenerated oil by exchanging heat with the exhaust gas flowing in the exhaust pipe 23b is provided in the fuel tank 3 of the regenerated oil that is a low-grade and high-viscosity fuel. As a result, it is possible to use the heat efficiently without waste by reusing the exhaust heat, and it is also possible to cool the exhaust gas. Furthermore, compared to a structure in which, for example, radiator water is used to heat the regenerated oil in the fuel tank 3, a simple and therefore reliable piping structure can be realized, and a rise in water temperature is awaited. Heating can be started quickly.

  Moreover, in the fuel supply apparatus 1 of the above embodiment, since the recycled fuel of waste cooking oil that is not subject to the volatile oil tax at the present time is used as the liquid fuel on the fuel supply line 5 side, the operating cost of the engine 2 is reduced. In addition to being able to reduce emissions, it is possible to consider the global environment by reusing resources.

  In the fuel supply device 1 of the above embodiment, the regenerated oil fuel tank 3 is provided with the regenerated oil reforming device 34 filled with a reforming catalyst that promotes fragmentation of the regenerated oil molecules. The regenerated oil can be easily ionized, and the combustion efficiency can be improved.

  In the fuel supply device 1 of the above embodiment, since control means (not shown) for switching the supplied liquid fuel to light oil in the fuel supply line 6 is provided before the operation of the engine 2 is stopped. The engine 2 can be reliably started not only with regenerated oil but also with light oil that is easy to burn even on the ground.

In the present embodiment, the fuel supply device 1 is exemplified as a configuration including two fuel supply lines. However, three or more fuel supply lines for supplying different types of liquid fuel are provided. It is good. Alternatively, any two or more of the three or more fuel supply lines may supply the same liquid fuel.

  Moreover, although the recycled oil and light oil of waste cooking oil were illustrated and demonstrated as multiple types of liquid fuel, it is not restricted to these examples. For example, instead of recycled oil, various biomass liquid fuels such as wood vinegar and water emulsion fuels thereof may be used as low cost and low environmental load fuels. Further, instead of light oil, an appropriate liquid fuel according to the type of heat engine, such as heavy oil or gasoline, may be used.

In the present embodiment, the fuel supply device 1 is exemplified as supplying fuel to the diesel engine 2, but combustion other than a heat engine such as a gas turbine or a heat engine such as a water heater boiler is used. The present invention can also be applied to a heat source or various burner combustion apparatuses.

1 is a system diagram showing a first embodiment of a fuel supply apparatus according to the present invention. It is an enlarged view which shows the principal part of 1st Embodiment of the fuel supply apparatus concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel supply apparatus 2 Engine 5, 6 Fuel supply line 7 Junction part 9 Fuel injection apparatus 10, 11 Check valve 16 Variable speed oil feed pump 22 Exhaust system 27 Heat exchanger 34 Recycled oil reformer

Claims (5)

A fuel suction means for supplying liquid fuel to the heat engine by suction; a plurality of fuel supply lines connected in parallel to the fuel suction means for supplying different types of liquid fuel; and each of these fuel supply lines, A check valve for preventing back flow of the liquid fuel sucked by the fuel suction means, and a fuel selection means for selecting which fuel supply line to suck the liquid fuel by the fuel suction means ,
The fuel selection means is provided between the check valve of each fuel supply line and the fuel suction means, and joins the fuel supply lines together with at least one of the fuel supply lines. A fuel supply apparatus comprising: a pumping unit that is provided upstream of the valve and pumps liquid fuel .   At least one of the fuels flowing through the plurality of fuel supply lines is a low-grade and high-viscosity fuel, and the fuel tank of the low-grade and high-viscosity fuel is supplied with exhaust gas and heat flowing through the exhaust system. The fuel supply device according to claim 1, further comprising a heat exchanger that exchanges and heats.   The fuel supply apparatus according to claim 2, wherein the low-grade high-viscosity fuel is a regenerated oil. At least one of the fuels flowing through the plurality of fuel supply lines is a low-load fuel that is easily combusted even during a low-load operation of the heat engine, and the fuel selection is performed after a shutdown operation of the heat engine. The fuel supply device according to any one of claims 1 to 3, further comprising control means for selecting a fuel supply line for the low load fuel by means.   The fuel supply device according to any one of claims 1 to 4, wherein the fuel suction means supplies liquid fuel to a combustion heat source such as a water heater boiler instead of the heat engine.

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