JP2008150984A - Emulsion fuel supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an emulsion fuel supply device capable of surely supplying emulsion fuel by simple control. <P>SOLUTION: An emulsion fuel supply device 5 makes emulsion fuel out of light oil, water and emulsifier supplied at a prescribed ratio of light oil:water = 7:3 or 8:2 and emulsifier of 1% or the like of the entire to be supplied to a diesel engine 3. The device includes an emulsion tank 15 for storing emulsion fuel and allowing the supply of a required amount to the diesel engine 3. The emulsion tank 15 consists of a first tank 43 for receiving the supply of emulsifier and a second tank 45 which stores the emulsion fuel made by introducing mixture of light oil, water and emulsifier in the first tank 43 so that the emulsion fuel is supplied to the diesel engine 3 and which overflows mixture of more than a certain amount to the first tank 43. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an emulsion fuel supply device for supplying emulsion fuel to a diesel engine.

  A technique for reducing nitrogen oxide (NOx) in exhaust gas of a diesel engine and suppressing generation of soot is known as Patent Document 1, for example. In this technology, water and an emulsifier are added to fuel (light oil or A heavy oil) to make an emulsion fuel, and this emulsion fuel is injected from the fuel injection valve into the combustion chamber and burned to reduce the combustion temperature, thereby suppressing NOx generation. Is.

  Here, an emulsion fuel supply device that creates emulsion fuel and supplies it to a diesel engine has the following configuration, for example.

  The emulsion fuel supply device includes a light oil tank, a water tank, and an emulsifier cartridge, and a fuel pump driven by an electric motor, a water pump, and an inlet of the emulsifier pump are connected to the light oil tank, the water tank, and the emulsifier cartridge, respectively. ing. The driving of these pumps is controlled independently by the emulsion controller. The discharge ports of the pumps pass through separate variable flow rate control valves (ratio adjusting devices), and then merge and flow into the inlet of the static mixer. Each flow area of the variable flow rate control valve is controlled independently by the emulsion controller. The outlet of the stationary mixer is connected to the suction port of the injection pump.

  Accordingly, the emulsion fuel can be generated by the static mixer and sent to the injection pump while the flow rate is adjusted according to the load by the variable flow control valve and the water ratio is changed.

  However, in the above structure, the generated emulsion fuel cannot be stored, the control by the variable flow control valve is complicated, and the supply of the emulsion fuel stops immediately when the variable flow control valve or the like fails. It was.

JP 2002-138906 A

  The problem to be solved is that the control by the variable flow rate control valve is complicated and the supply of the emulsion fuel is immediately stopped when the variable flow rate control valve or the like fails.

  The present invention provides an emulsion fuel supply apparatus for producing emulsion fuel from fuel, water, and emulsifier supplied at a predetermined ratio and supplying the emulsion fuel to a diesel engine in order to reliably supply the emulsion fuel by simple control. An emulsion tank is provided for storing emulsion fuel and allowing the required amount to be supplied to the diesel engine. The emulsion tank is a tank for mixing, receiving and supplying fuel, water, and emulsifier, and for fuel, water, and emulsifier in the mixing tank. The most important feature is that the emulsion fuel produced by introducing the mixed liquid can be stored in order to supply it to the diesel engine and at the same time comprises a storage tank that allows a certain amount or more to overflow into the mixing tank.

  The present invention relates to an emulsion fuel supply device for producing emulsion fuel from fuel, water, and emulsifier supplied at a predetermined ratio and supplying the emulsion fuel to a diesel engine, storing the emulsion fuel and supplying a necessary amount to the diesel engine. An emulsion tank that can be supplied, and the emulsion tank is configured to introduce an emulsion fuel produced by introducing a mixture of fuel, water, and emulsifier supplied from the fuel, water, and emulsifier, and a mixture of fuel, water, and emulsifier. It is made up of a storage tank that allows a reservoir to be supplied to the mixing tank and allows a certain amount or more to overflow to the mixing tank. Therefore, the fuel, water, and emulsifier supplied to the mixing tank are guided to store the produced emulsion fuel. Can be stored in a storage tank, and the required amount is supplied to the diesel engine from this storage tank Door can be.

Therefore, even if the control of the variable flow rate control valve becomes unnecessary and the supply of fuel, water, and emulsifier to the mixing tank is stopped due to a failure, the emulsion fuel is stored in the storage tank. Can be continued for a predetermined time.
In addition, the fuel, water, and emulsifier already supplied to the mixing tank can be guided and the produced emulsion fuel can be sent to the storage tank, so the emulsion fuel can be supplied by effectively using the capacity of the entire emulsion tank. Can continue.

  The objective of reliably supplying the emulsion fuel by simple control was realized by an emulsion tank comprising a mixing tank and a storage tank.

[Vehicle and exhaust purification system 1]
FIG. 1 is a plan view showing a skeleton of a vehicle equipped with a diesel engine exhaust purification system according to an embodiment of the present invention, and FIG. 2 is a configuration diagram showing a diesel engine exhaust purification system 1 according to an embodiment of the present invention. It is.
As shown in FIGS. 1 and 2, the exhaust purification system 1 includes an emulsion fuel supply device 5 and an oxidation catalyst device 7 for the diesel engine 3. The emulsion fuel supply device 5 is for mixing the fuel, water and emulsifier to produce emulsion fuel and supplying it to the diesel engine 3. The emulsion fuel supply device 5 is not limited to the one that produces emulsion fuel in an on-vehicle state, but is equipped with a tank that stores emulsion fuel that has been created in advance, and is configured to supply emulsion fuel as needed from this tank. You can also. The oxidation catalyst device 7 is for purifying HC, CO and the like in exhaust gas by combustion in the diesel engine 3 by oxidation.
The emulsion fuel supply device 5 stores a light oil tank 9, a water tank 11, an emulsifier tank 13, and an emulsion tank 15 that is an emulsion tank. The light oil tank 9 stores light oil as fuel. As fuel, A heavy oil can also be used. Water is stored in the water tank 11. The emulsifier tank 13 stores an emulsifier. The emulsion tank 15 mixes the light oil, water, and emulsifier supplied from the light oil tank 9, the water tank 11, and the emulsifier tank 13 at a predetermined ratio to produce an emulsion fuel, and supplies this emulsion fuel to the diesel engine 3. .
The light oil tank 9, the water tank 11, and the emulsifier tank 13 and the emulsion tank 15 are connected by a light oil pipe 17, a water pipe 19, and an emulsifier pipe 21. One end of each of the pipes 17, 19, and 21 faces the inner bottom side of the light oil tank 9, the water tank 11, and the emulsifier tank 13, and the other end faces the upper part of the emulsion tank 15. Strainers 23 and 25 are attached to one end of the water pipe 19 and the emulsifier pipe 21.
The light oil pipe 17 is provided with a light oil pump 27 and a filter 29 of a light oil pump unit 26, and the water pipe 19 is provided with a water pump 31 and an electromagnetic valve (two-way valve) 33 connected thereto. An emulsifier pump 35 is interposed in the emulsifier pipe 21. Each of the pumps 27, 31, and 35 is an electromagnetic pump in this embodiment, and the electric drive is independently controlled by the control unit 37. Under the control of the pumps 27, 31, and 35, for example, light oil: water = 7: 3 (or 8; 2) or the like is sent out. As the emulsifier, a solution obtained by diluting an emulsifier stock solution twice with kerosene or light oil in advance is used, and the diluted emulsifier is sent out so as to be 2% of the whole by the control of the pump 35. The switching of the electromagnetic valve 33 is controlled by the control unit 37.
A receiving tray 39 formed of a mesh or a perforated plate is provided in the upper part of the emulsion tank 15 and receives fuel, water, and emulsifier discharged from the pipes 17, 19, and 21. Note that the tray 39 can be formed of a non-porous metal plate or the like.
The emulsion tank 15 is partitioned by a partition wall 41 into a first tank 43 as a mixing tank and a second tank 45 as a storage tank. Each of the mixing tank and the storage tank can be composed of a plurality of tanks.
In the first tank 43, the fuel, water, and emulsifier that fall through the tray 39 are mixed. In the second tank 45, emulsion fuel is stored. The emulsion fuel overflowing from the second tank 45 is returned to the first tank 43.
The emulsion tank 15 is provided with an upper limit level sensor 47 and a lower limit level sensor 48. Detection signals from the sensors 47 and 48 are input to the control unit 37, and the driving of the pumps 27, 31 and 35 is controlled by the control unit 37.
The upper limit level sensor 47 detects the upper limit of the liquid mixture in the first tank 43. This upper limit is set at a position lower than the partition wall 41 that determines the liquid level height of the second tank 45. The lower limit level sensor 48 detects the lower limit of the liquid mixture in the first tank 43. Accordingly, the control unit 37 drives the pumps 27, 31, and 35 so that the liquid level in the first tank 43 is between the upper and lower limits determined by the upper limit level sensor 47 and the lower limit level sensor 48. Be controlled.
A mixing pipe 49 is connected to the bottom of the emulsion tank 15 to allow communication between the bottoms of the first tank 43 and the second tank 45. In the mixing pipe 49, a mixing pump 50, a filter 51, and a mixer 53 are interposed. The mixing pump 50, the filter 51, and the mixer 53 constitute a mixing unit 54.
The mixing pump 50 is driven by an electric motor, and the drive is controlled by the control unit 37. The mixer 53 includes a mixer element, which will be described later, and makes emulsion fuel by passing the mixed liquid sent from the first tank 43 by the mixing pump 50 through the mixer element, which will be described later, and sends it to the second tank 45. .
A premix pipe 55 is connected to the upstream side of the emulsion tank 15. One end of the premix pipe 55 faces the inner bottom side of the first tank 43 and the other end faces the outside of the upper liquid surface.
A premix pump 57 is interposed in the premix pipe 55. The premix pump 57 is an electromagnetic pump in this embodiment, and the electric drive is controlled by the control unit 37.
The second tank 45 of the emulsion tank 15 and the engine feed pump 59 are connected by an emulsion supply pipe 61. One end of the emulsion supply pipe 61 faces the bottom side of the second tank 45, and a strainer 63 is attached. A check valve 65 is interposed in the emulsion supply pipe 61.
The feed pump 59 is connected to the injection pump 67 so that the emulsion fuel can be supplied to the injection nozzle 69 of the diesel engine 3 by the control of the injection pump 67 by the engine control unit 68.
A return pipe 71 connects between the injection pump 67 and the first tank 43 of the emulsion tank 15.
The emulsion supply pipe 61 and the light oil tank 9 are connected by an interrupt pipe 73. One end of the interrupt pipe 73 faces the inner bottom side of the light oil tank 9, and the other end is connected to the emulsion supply pipe 61 between the feed pump 59 and the check valve 63.
The interrupt pipe 73 is provided with an interrupt pump 75 and a solenoid valve 77 of the light oil pump unit 26. The interrupt pump 75 is an electromagnetic pump in this embodiment, and the electric drive is controlled by the control unit 37. The solenoid valve 77 is controlled by the control unit 37 to open and close and to adjust the opening.
[Exhaust air purification system 1A]
FIG. 3 is a block diagram showing an exhaust purification system 1A for a diesel engine according to an embodiment of the present invention in which the connection position of the interrupt pipe is changed.
Instead of the exhaust purification system 1 of FIG. 2, it can also be configured as an exhaust purification system 1A of FIG. In this exhaust purification system 1 </ b> A, the interrupt pipe 73 </ b> A is connected between the feed pump 59 and the injection pump 67. Further, instead of the electromagnetic valve 77 of the exhaust purification system 1, a check valve 77A is used in the exhaust purification system 1A.
[Oxidation catalyst equipment]
The oxidation catalyst device 7 is provided in the exhaust system of the diesel engine 3 and purifies exhaust gas by combustion in the diesel engine 3 supplied with emulsion fuel by oxidation. The oxidation catalyst device 7 includes a main catalyst device 79 and a sub catalyst device 81. The main catalyst device 79 has a relatively large capacity compared to the sub catalyst device 81. The sub catalyst device 81 has a relatively small capacity compared to the main catalyst device 79. In this embodiment, the sub catalyst device 81 has a capacity of 5 to 15% of the main catalyst device 79.
The main catalyst device 79 is interposed in the exhaust pipe 80 in the exhaust system outside the engine room, that is, below the floor of the vehicle floor. The sub-catalyst device 81 is disposed upstream of the main catalyst device 79 in the exhaust system of the diesel engine 3, preferably in the engine room. In the present embodiment, the sub-catalyst device 81 is interposed in the exhaust pipe 80 immediately after the downstream side of the exhaust manifold 83 having a high exhaust gas temperature.
[mixer]
4 to 6 are schematic cross-sectional views of the mixer. FIG. 4 shows an example in which a single mixer element is provided, and FIG. 5 is a diagram in which a plurality of mixer elements are connected with a gap between each other. FIG. 6 shows an example in which a plurality of mixer elements are connected in series with a net spacer interposed therebetween.
The mixer 53 shown in FIG. 4 is configured such that a single mixer element 87 is housed and supported in an element housing portion 85 having a large diameter that is connected to the mixing pipe 49 and forms a pipe line. The mixer element 87 is formed of a lump obtained by deforming and compressing a fine metal wire that produces an emulsion fuel by stirring when the mixed liquid is passed therethrough. In this embodiment, the mixer element 87 is, for example, a metal wire having a wire diameter of about 0.08 mm that is randomly rounded and compression-molded to form a compressed lump having a predetermined compression density, or a wire mesh having a wire diameter of about 0.08 mm is randomly selected. A compact that has been compressed into a compacted mass with a predetermined compression density is used. The compression density is, for example, about 0.5 g with a length of 10 mm and a diameter of 6 mm.
A plurality of the mixer elements 87 may be arranged in the element storage portion 85 in a state of being separated from each other by a predetermined distance.
The mixer 53 shown in FIG. 5 is configured such that, for example, four mixer elements 87 are stored and supported in an element storage portion 85 with a space between each other. A ring spacer 89 is interposed between the mixer elements 87, and a gap 91 is formed between the mixer elements 87.
The mixer 53 shown in FIG. 6 is also one in which, for example, four mixer elements 87 are stored and supported in the element storage portion 85 with a space between each other. A net spacer 93 is interposed between the mixer elements 87. As with the mixer element 87, the net spacer 93 is made of a fine metal wire or a wire mesh, and is configured as a lump having a smaller density by compression than the mixer element 87. Therefore, at least two mixer elements 87 in FIG. 6 have different compression densities. The connected mixer elements 87 may be configured to gradually change the compression density from the upstream side of the mixed solution. That is, the mixer elements 87 can have different compression densities between three or more.
[Emulsion fuel supply, emulsion tank]
When the key switch is set to the ready position when the engine is started, the light oil pump 27, the water pump 31, the emulsifier pump 33, the premix pump 57, and the mixing pump 50 are driven in advance under the control of the control unit 37.
By driving the light oil pump 27, the water pump 31, and the emulsifier pump 33, the light oil tank 9, the water tank 11, and the emulsifier tank 13 pass through the light oil pipe 17, the water pipe 19, and the emulsifier pipe 21 to the emulsion tank 15 at a certain ratio. , Water and emulsifier are sent.
In the emulsion tank 15, light oil, water, and emulsifier are discharged from the pipes 17, 19, and 21 onto the tray 39 and are slightly mixed by the discharge force. The light oil, water, and emulsifier mixed together fall through the mesh of the tray 39 or the like, overflow downward and are received into the first tank 43.
The liquid mixture in the first tank 43 is pumped up through the premix pipe 55 by the drive of the premix pump 57 under the control of the control unit 37, and mixing is promoted by falling and returning.
Due to the rotation of the mixing pump 50 under the control of the control unit 37, the mixed liquid in the first tank 43 passes through the mixing pipe 49 to the mixer 53, and the mixed liquid passes through the mixer 53 to become emulsion fuel. The tank 45 is reached.
When the emulsion fuel in the second tank 45 reaches a certain level or more, it overflows and returns to the first tank 43, is mixed with the liquid mixture before emulsification, and passes through the mixer 53 again. Therefore, the produced | generated emulsion fuel can be stored in the 2nd tank 45, and emulsion fuel can be supplied to the diesel engine 3 without delay.
Here, the upper limit level sensor 47 and the lower limit level sensor 48 of the first tank 43 monitor the liquid level, and a detection signal is input to the control unit 37. Accordingly, when the liquid level reaches the upper limit, the light oil pump 27, the water pump 31, and the emulsifier pump 33 are stopped by the control of the control unit 37, and the supply of the light oil, water, and the emulsifier to the first tank 43 is stopped. When the liquid level reaches the lower limit, the light oil pump 27, the water pump 31, and the emulsifier pump 33 are re-driven by the control of the control unit 37, and the supply of light oil, water, and emulsifier to the first tank 43 is resumed.
With this control, if the supply of light oil, water, and emulsifier is greater than the amount of emulsion fuel used, the supply of light oil, water, and emulsifier is periodically stopped.
If the mixing pump 50 is kept rotating while the supply of light oil, water, and emulsifier is larger than the amount of emulsion fuel used, the overflow from the second tank 45 to the first tank 43 continues. Due to this overflow, the liquid in the first tank 43 passes through the mixer 53 many times, and sufficient emulsification becomes possible.
The mixer 53 mixes the supplied light oil, water, emulsifier, return fuel, and emulsion fuel to produce a water-in-oil type (W / O type) emulsion fuel, which is sent to the injection pump 67. .
The water ratio for producing the water-in-oil type (W / O type) emulsion fuel is set as follows. In this case, the water ratio indicates the volume ratio, but the mass ratio hardly changes. The emulsifier has an HLB of about 3.5 to 6 that represents a balance between hydrophilicity and lipophilicity. The water ratio can be changed according to the running load, but in this embodiment, the range in which the light oil: water is approximately 7: 3 or 8: 2 is selected and set during normal running.
As a result, the combustion temperature in the engine is suppressed by the emulsion fuel, and the generation of N0x is greatly reduced. In addition, by properly adjusting and generating the W / O emulsion fuel, it is possible to suppress the direct contact of the water component with the injection nozzle 69, the injection pump 67, and the like, and to suppress the rust of these fuel injection systems and the like. it can. Furthermore, microexplosion of emulsion fuel with water can be expected, and it has been confirmed through experiments that the fuel consumption rate is improved.
When a certain amount of time has passed since the key switch was set to the ready position, it was informed that the emulsion fuel was ready by turning on the indicator lamp 95, etc. Then, when the starter was turned on by turning on the starter switch, the diesel engine 3 was rotated. Power is given.
The emulsion fuel is sent from the second tank 45 of the emulsion tank 15 to the injection pump 67 through the emulsion supply pipe 61 by the rotation of the feed pump 59. The injection pump 67 is controlled by the engine control unit 68, and fuel is injected from the injection nozzle 69 at an optimal injection timing for an optimal injection time. Excess emulsion fuel remaining at the injection pump 67 passes through the return pipe 71 and returns into the first tank 43 of the emulsion tank 15.
In the diesel engine 3, the injected emulsion fuel is ignited and combusted by intake air and compression heat. The engine can be rotationally driven by the gas expansion caused by the combustion.
By using the emulsion fuel in this way, generation of NOx is reduced by suppressing the maximum combustion temperature in the diesel engine 3.
[Exhaust gas purification by oxidation catalyst]
The exhaust gas after combustion passes through the exhaust pipe 80 from the exhaust system, that is, the exhaust manifold 83, and is discharged. When passing through the exhaust pipe 80, PM, HC and CO discharged from the engine are oxidized by the sub catalyst device 81 and the main catalyst device 79, and the exhaust gas is purified.
In a low exhaust gas temperature range, such as during low-load operation or engine startup, the exhaust gas is accelerated by the sub-catalyst device 81 at a position where the exhaust gas temperature is as close as possible to the diesel engine 3 and exhausted by an oxidation reaction. The gas itself is also heated. For this reason, it is possible to expect a reaction in the main catalyst device 79 on the downstream side, and it is possible to exhibit a sufficient purification ability even in a low combustion temperature region together. Further, since the amount of exhaust gas discharged is originally small in this region, a substantial portion can be oxidized and purified by the sub-catalyst device 81 as well.

On the other hand, in the high engine speed range where the exhaust gas flow rate is large, the capacity of the sub-catalyst device 81 is not sufficient to oxidize and purify the exhaust gas. However, the exhaust gas in this region originally has a sufficiently high exhaust gas temperature. Even if the purification capacity of the catalyst device 81 is exceeded, a sufficient reaction can be expected in the main catalyst device 79 on the downstream side having a large capacity, and a sufficient purification capacity can be exhibited.
The sub-catalyst device 81 is relatively smaller in capacity than the main catalyst device 79 and has a capacity of 5 to 15% of that of the main catalyst device 79. Therefore, the sub-catalyst device 81 has a particularly small space in the exhaust manifold 83. Immediately after the downstream side, it can be arranged without difficulty in space, and the main catalyst device 79 can be arranged under the floor with sufficient space. For this reason, the sub-catalyst device 81 and the main catalyst device 79 can be arranged without difficulty while exhibiting a sufficient exhaust gas purification capability.
[Emulsification with mixer]
Emulsification by the mixer 53 is performed as follows. That is, the mixed solution pumped to the mixer 53 by the rotation of the mixing pump 50 passes through the lump of linear metal wires by passing through the mixer element 87 as shown in FIG. At this time, the liquid mixture passes through a complicated flow path at high speed, the water and gas oil particles of the liquid mixture are further refined, sufficient emulsification is performed, and a W / O type emulsion fuel is generated. . The emulsion fuel produced by the mixer 53 reaches the second tank 45.
When the mixer 53 has the configuration shown in FIG. 4, that is, a configuration in which a plurality of mixer elements 87 are connected with gaps 91, each mixer element 87 performs the emulsification for that number of pieces and The mixing and condensing action of once the mixed liquid is once mixed and again passes through the next mixer element 87 is repeated, and emulsification can be promoted by one tank.
When the mixer 53 has the configuration shown in FIG. 5, that is, a configuration in which a plurality of mixer elements 87 are connected via the net spacers 93, each mixer element 87 performs the emulsification for that number and Emulsification is promoted together with the mixing of the liquid reaching the spacer 93 by a coarser linear lump, and the mixing and scattering action of passing again through the next mixer element 87 is repeated, so that emulsification can be promoted by one tank.
Such a pipe-type mixer 53 can form a minute and complicated flow path very easily, and an inexpensive and high-performance pipe-type mixer 53 can be obtained.
[Light oil interruption]
In the exhaust purification system 1 of FIG. 2, the interrupt pump 75 is driven and the electromagnetic valve 77 is adjusted to open by the control of the control unit 37. As a result, light oil can be pumped from the light oil tank 9 through the interrupt pipe 73 to the emulsion supply pipe 61 just before the feed pump 59 and the diesel fuel supplied to the diesel engine 3 can be interrupted with light oil. The amount of light oil to be interrupted can be adjusted by adjusting the discharge amount of the interrupt pump 75 and adjusting the opening of the electromagnetic valve 77 by the control unit 37.
When the diesel engine 3 is driven by emulsion fuel, the output decreases compared to the case of light oil fuel only at the time of high load such as maximum output, so the diesel oil ratio of the emulsion fuel can be easily increased by interrupting the diesel oil, It can compensate for the decrease in output.
That is, the interrupt pump 75 is driven during high load traveling such as uphill traveling and acceleration traveling, and the opening of the electromagnetic valve 77 is adjusted according to the load to increase the ratio of light oil. When the vehicle is traveling at a low load such as high-speed cruise traveling, the interrupt pump 75 is stopped and the electromagnetic valve 77 is closed. Thereby, the light oil: water of the emulsion fuel is set to approximately 7: 3 or 8: 2, etc., and the water ratio increases. As a result, NOx is greatly reduced, and PM (particulate matter), HC, and CO are also processed by the oxidation catalyst device 7. The determination as to whether the vehicle is traveling under high load or low load can be made by detecting the vehicle speed and the accelerator opening.
At the time of sudden acceleration, since the acceleration performance must be emphasized to ensure safety during overtaking, the light oil ratio is adjusted so that the ratio of light oil: water is approximately 90:10 to 95: 5. Reduce the water ratio by In this case, NOx deteriorates, but since the rapid acceleration time is usually short, the total amount of NOx generated does not increase that much. In addition, since water is contained at a ratio of about 5 with respect to the light oil 95 at least, it is possible to suppress the generation amount of NOx without sacrificing the acceleration performance as compared with when there is no water. In this case, since the amount of PM generated decreases, the burden on the oxidation catalyst device 7 is reduced.

When the engine is started and when the engine is idling, the ratio of light oil is increased so that the ratio of light oil: water is approximately 95: 5. As a result, the startability of the engine can be improved and the idling operation can be stably performed. In this case, the generation of PM is reduced as a result of the water ratio being reduced. In addition, when the load is relatively light, such as when idling, even if the ratio of the light oil is large (small water ratio), NOx is small, whereas when the water ratio is large, a large amount of PM, HC, and CO is generated. For this reason, it is effective to increase the light oil ratio at a light load such as when the engine is started or idling.
When the key is turned off to stop the engine, the light oil pump 27, the water pump 31, the emulsifier pump 35, the mixing pump 50, and the premix pump 57 are stopped, and only the interrupt pump 75 is continuously driven, so that the fuel of 100% light oil Can also be ejected from the ejection nozzle 69. By stopping the rotation of the engine after the light oil injection, water and emulsion fuel do not remain in the injection nozzle 69, the injection pump 67 and the like after the stop, so that rusting of these fuel injection systems can be suppressed.
Instead of key-off for stopping the engine, it is also possible to switch to this stop control when the parking brake is applied or when the idling operation state continues for a predetermined time or longer.
In the exhaust purification system 1A of FIG. 3 as well, the same function can be achieved by light oil interruption. However, in the exhaust purification system 1 </ b> A, the emulsion is supplied to the diesel engine 3 by driving the interrupt pump 75 to pump light oil from the light oil tank 9 through the interrupt pipe 73 </ b> A between the feed pump 59 and the injection pump 67. Light oil interruption can be performed on the fuel. The amount of light oil to be interrupted can be controlled by driving control of the interrupt pump 75 by the control unit 37.
[Water adjustment for returned light oil]
When the light oil interruption is performed in the exhaust purification systems 1 and 1A of FIGS. 2 and 3, the light oil ratio of the return fuel returning from the return pipe 71 to the first tank 43 of the emulsion tank 15 increases.
For this reason, the supply ratio of the light oil and water is adjusted by controlling the light oil pump 27 and the water pump 31 by the control unit 37, and the ratio of light oil: water in the first tank 43 of the emulsion tank 15 is set to 7: 3 or 8 : It can be kept constant as 2 etc.
This control is performed by controlling the interrupt pump 75 and the solenoid valve 77 (exhaust purification system 1) or by controlling the interrupt pump 75 (exhaust purification system 1A). This can be done by obtaining the light oil ratio of the return fuel based on the fuel injection amount that can be known by the control of the injection pump 67.
[Freeze prevention]
The water pipe 19 may be frozen at low temperatures such as in winter. As a countermeasure against this freezing, when the key switch is turned off to stop the engine, the control unit 37 controls the electromagnetic valve (two-way valve) 33 to switch to the open state.
By this switching, the water in the water pipe 19 returns to the water tank 11 by gravity below the electromagnetic valve 33. By continuing to drive the water pump 31 in this state, air is sucked from the electromagnetic valve 33 side, and the water in the water pipe 19 can be discharged into the emulsion tank 15 between the water pump 31 and the emulsion tank 15. it can.
It is possible to prevent water from remaining by draining water from the water pipe 19 as described above, to suppress freezing in the water pipe 19 and to smoothly restart the engine.
The water tank 11 is preferably covered with a heat insulating material. However, even when the water tank 11 is not covered with the heat insulating material, the water capacity in the water tank 11 is large, so that it is more difficult to freeze than in the water pipe 19.
When water is drained from the water pipe 19 to the emulsion tank 15 side when the engine is stopped, the ratio of light oil: water in the emulsion tank 15 changes, and water is increased by the amount drained to the emulsion tank 15 side. It is also possible to continue the driving of the light oil pump 27 in accordance with the amount of drainage and to control to supply the same amount of light oil into the emulsion tank 15.
When control is performed to supply light oil according to the amount of water drained to the emulsion tank 15 when the engine is stopped, when the engine is started, the water that is driven by the water pump 31 reaches the emulsion tank 15 at the same time or when it reaches. It is preferable to perform control to drive the light oil pump 27 immediately before. It can be known by providing a flow rate sensor in the water pipe 19 that water driven by the water pump 31 reaches the emulsion tank 15 at the same time or just before the water reaches.
Even when the control to supply light oil according to the amount of water drained to the emulsion tank 15 side is not performed when the engine is stopped, the amount of light oil corresponding to the amount of water drained to the emulsion tank 15 side is started at the time of starting. 15 can be controlled to drive the light oil pump 27 so as to be supplied first.

[Effect of Example]
In an embodiment of the present invention, an emulsion fuel supply device 5 for producing emulsion fuel from light oil, water, and emulsifier supplied at a predetermined ratio and supplying the emulsion fuel to a diesel engine 3 stores the emulsion fuel and supplies the required amount. An emulsion tank 15 that can be supplied to the diesel engine 3 is provided. The emulsion tank 15 is configured to receive the light oil, water, and the emulsifier of the first tank 43 and the first tank 43 that are supplied with the light oil, water, and the emulsifier. Since the emulsion fuel produced by introducing the mixed liquid can be stored in order to supply the diesel engine 3 to the diesel engine 3, the second tank 45 has a second tank 45 that allows a certain amount or more to overflow to the first tank 43. Lead the light oil, water and emulsifier supplied to 45 and store the produced emulsion fuel in the second tank 45 Can, it is possible to supply the necessary amount from the second tank 45 to the diesel engine 3.

Therefore, the control of the variable flow rate control valve becomes unnecessary, and even if the supply of the light oil, water, and the emulsifier to the first tank 43 is stopped due to a failure, the emulsion fuel is stored in the second tank 45. The supply of fuel can be continued for a predetermined time.
In addition, since the light oil, water, and emulsifier already supplied to the first tank 43 can be guided and the produced emulsion fuel can be sent to the second tank 45, the entire capacity of the emulsion tank 15 can be effectively utilized. The supply of emulsion fuel can be continued.
A mixing pump 50 that pumps the mixed liquid from the first tank 43 to the second tank 45, and a mixer that creates emulsion fuel by passing the mixed liquid pumped by the mixing pump 50 and sends it to the second tank 45 side. 53, the emulsion fuel can be produced with a simple structure and can be reliably stored in the second tank 45.

  In the mixer 53, a mixer element 87 is disposed in a pipe line of a mixing pipe 49 that communicates and connects the first tank 43 and the second tank 45. The mixer element 87 is a compression made of a thin metal wire. Since it is a lump, it is possible to reliably produce an emulsion fuel with a simple structure.

  Since the premix pipe 55 and the premix pump 57 that pump up the mixed liquid in the first tank 43 and drop and return onto the liquid surface in the first tank 43 to promote the mixing of the liquid in the first tank 43 are provided. The light oil, water, and emulsifier in one layer 43 can be reliably mixed.

An upper limit level sensor 47 for detecting the upper limit of the liquid level in the first tank 43 and a lower limit level sensor 48 for detecting the lower limit are provided, and the upper limit of the liquid level detected by the upper limit level sensor 47 is the second level sensor. Since it is lower than the overflow limit of the liquid level in the tank 45, a predetermined amount of light oil, water, and emulsifier is retained in the first tank 43, and the overflow from the second tank 45 to the first tank 43 is reliably performed. The emulsification can be surely promoted while the emulsion fuel is reliably stored in the second tank 45.
[Others]
The ratio of the light oil and water to the emulsion tank 15 can be adjusted by controlling the light oil pump 27 and the water pump 31 by the control unit 37 according to the load.

  In addition, the emulsion fuel is not prepared and stored in advance as a predetermined proportion of emulsion fuel as in this embodiment, but the amount of light oil, water, and emulsifier is adjusted according to the operating conditions each time. However, it may be produced in a mixer and supplied to the diesel engine 3.

A plurality of emulsifiers can be mixed and used according to the HLB of the target light oil (A heavy oil).
The ratio of the emulsifier varies depending on the type of the emulsifier, and there are some which are effective even when the emulsifier stock solution is less than 1% of the whole.

  The mixer element 87 only needs to promote emulsification and secure a flow rate, and the wire diameter, diameter, and length are not limited to those described above, and can be variously changed. For example, the wire diameter of the fine metal wire can be made smaller than 0.08 mm, and the compression density is not limited to the above, but for example, the wire diameter is 0.08 mm, the length is 10 mm, and the diameter is 6 mm. A range of about 3 g to 0.7 g can also be selected. Further, if the diameter of the mixer element 87 is increased, the flow rate can be secured even if the compression density is further increased. Even when the compression density is as described above, the diameter of the mixer element 87 can be increased in accordance with the required flow rate. The mixing effect can be enhanced by further increasing the length of the mixer element 87.

  The light oil interruption may be performed only by adjusting the discharge amount of the interruption pump 75, and the electromagnetic valve 77 may be configured as an on-off valve that does not adjust the opening degree.

1 is a plan view showing a skeleton of a vehicle equipped with a diesel engine exhaust purification system 1 (Example 1). FIG. 1 is a configuration diagram showing an exhaust gas purification system for a diesel engine (Example 1). FIG. It is a block diagram which shows the exhaust gas purification system of the diesel engine which changed the connection position of interruption piping (Example 1). It is a schematic sectional drawing of the mixer which shows the example provided with the single mixer element (Example 1). It is a schematic sectional drawing of the mixer which shows the example by which the several mixer element was continuously arranged on both sides of the space | gap (Example 1). It is a schematic sectional drawing of the mixer which shows the example by which the several mixer element was continuously arranged on both sides of the net spacer (Example 1).

Explanation of symbols

1,1A Exhaust gas purification system 3 Diesel engine 5 Emulsion fuel supply device 15 Emulsion tank (emulsion tank)
43 1st tank (mixing tank)
45 Second tank (storage tank)
47 Upper limit level sensor 48 Lower limit level sensor 50 Mixing pump 53 Mixer 87 Mixer element 89 Ring spacer 91 Air gap 93 Net spacer

Claims (9)

In an emulsion fuel supply device for producing emulsion fuel from fuel, water and emulsifier supplied at a predetermined ratio and supplying it to a diesel engine,
An emulsion tank for storing the emulsion fuel and allowing the required amount to be supplied to the diesel engine;
The emulsion tank can be stored in order to supply to the diesel engine the emulsion fuel produced by guiding the fuel, water, and emulsifier mixed liquid supplied from the fuel, water and emulsifier. And a storage tank that allows a certain amount or more to overflow to the mixing tank side,
An emulsion fuel supply device characterized by the above. The emulsion fuel supply device according to claim 1,
A mixing pump for pumping the mixed liquid from the mixing tank to the storage tank;
A mixer that creates emulsion fuel by passing the liquid mixture pumped by the mixing pump and sends it to the storage tank side;
An emulsion fuel supply device characterized by comprising: The emulsion fuel supply device according to claim 2,
The mixer is one in which a mixer element is disposed in a pipe line connecting the mixing tank and the storage tank.
The mixer element is composed of a lump obtained by deforming and compressing a fine metal wire that creates emulsion fuel by stirring when the mixed liquid is passed through.
An emulsion fuel supply device characterized by the above. The emulsion fuel supply device according to claim 3,
A plurality of the mixer elements are arranged in a continuous manner at a predetermined distance from each other in the pipeline.
An emulsion fuel supply device characterized by the above. The emulsion fuel supply device according to claim 4,
The mixer elements have different compression densities between at least two.
An emulsion fuel supply device characterized by the above. The emulsion fuel supply device according to claim 4 or 5,
A ring spacer is interposed between the mixer elements to form a gap between the adjacent mixer elements.
An emulsion fuel supply device characterized by the above. The emulsion fuel supply device according to claim 4 or 5,
A net spacer having a smaller compression density than the mixer element is interposed between the mixer elements.
An emulsion fuel supply device characterized by the above. The emulsion fuel supply device according to any one of claims 1 to 7,
A premix pipe and a premix pump that pump up the mixed liquid in the mixing tank and drop and return onto the liquid surface in the mixing tank to promote mixing of the liquid in the mixing tank are provided.
An emulsion fuel supply device characterized by the above. The emulsion fuel supply device according to any one of claims 1 to 8,
An upper limit level sensor for detecting the upper limit of the liquid level in the mixing tank and a lower limit level sensor for detecting the lower limit are provided,
The upper limit of the liquid level detected by the upper limit level sensor is lower than the overflow limit of the liquid level of the storage tank,
An emulsion fuel supply device characterized by the above.

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