JP2006002668A - Fuel fractional distillation device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel fractional distillation device of an internal combustion engine which achieves reduction in cost and improvement in mountability, or reduction in energy required for fractional distillation. <P>SOLUTION: The fuel fractional distillation device is equipped with a fractional distillation part 17 for fractionating fuel into a gas phase and a liquid phase, a fuel feed pump 28 for pumping up fuel from a fuel tank 7, a plunger pump 29 for pressurizing fuel pumped up with the fuel feed pump 28, and a light fuel feed pump 30 for feeding fuel fractionated to the gas phase side in the fractional distillation part 17 to an exhaust passage 3 of an engine 1. The fuel feed pump 28, plunger pump 29 and light fuel feed pump 30 are arranged to be driven by a common driving shaft 31 respectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel fractionating device for an internal combustion engine that fractionates fuel into a liquid phase and a gas phase.

  As a fuel fractionation device, a device is known in which fuel pumped from a fuel tank by a low-pressure pump is led to a fractionation chamber, fractionated into a light fraction and a heavy fraction, and these are supplied to the engine in separate systems ( Patent Document 1). Other prior art documents relating to the present invention include Patent Documents 2 and 3.

JP 2001-193525 A JP-A-6-93833 JP 2002-242780 A

  In such an apparatus, a pump that supplies the fuel that has been fractionated to the gas phase side by fuel fractionation to the engine and a pump that supplies the fuel that has been fractionated to the liquid phase side to the engine must be prepared separately. This increases the cost. In addition, the space for mounting these pumps must be secured, so that the mounting property is poor.

  Further, in order to fractionate the fuel, it is necessary to heat the fuel to a temperature at which fractionation is possible. Therefore, the lower the temperature of the fractionated fuel, the more energy is required for fractionation. Since the temperature in the fuel tank is low (generally, the upper limit is about 20 ° C.), much energy is required to immediately fractionate the fuel pumped from the fuel tank as in the conventional apparatus.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel fractionation device for an internal combustion engine that can improve the mountability at the same time as the cost reduction or can reduce the energy required for fractionation.

  A first fuel fractionation device according to the present invention includes a fractionation unit for fractionating fuel into a gas phase and a liquid phase, a fuel feed pump for pumping fuel from a fuel tank, and fuel pumped by the fuel feed pump. A pressurizing pump for pressurizing, and a light fuel feed pump for supplying the fuel fractionally distilled in the fractionation unit to a predetermined supply destination, the fuel feed pump, the pressurizing pump, and the Each of the light fuel feed pumps is arranged so as to be driven by a common drive shaft, thereby solving the above-described problem.

  In an apparatus that separates fuel into a liquid phase and a gas phase at a fractionation unit and uses the fuel (gas phase fuel) fractionated on the gas phase side, a pump that supplies the fuel to a predetermined supply destination is provided. Necessary. According to the present invention, since the fuel feed pump, the pressure pump, and the light fuel feed pump are each driven by a common drive shaft, a dedicated pump for supplying the fractionated fuel to a predetermined supply destination is provided. There is no need to provide it separately. Therefore, the cost associated with the additional installation of the dedicated pump can be reduced. In addition, since it is not necessary to secure the location of each pump, the mountability of the pump is improved.

  The second fuel fractionating device of the present invention includes a feed pump that pumps fuel from a fuel tank, a pressurizing pump that pressurizes the fuel pumped by the feed pump, and accumulating fuel pressurized by the pressurizing pump. A common rail, a return passage for returning the fuel from the common rail to the fuel tank, and a fractionation unit for fractionating the fuel guided to the return passage into a gas phase and a liquid phase. The problem is solved (claim 2).

  In general, since the fuel returned from the common rail to the fuel tank is in a high temperature state, fuel having a temperature higher than that in the fuel tank flows in a return passage through which the fuel is guided. Incidentally, the temperature of the fuel returned from the common rail is about 100 ° C., and the temperature of the fuel in the fuel tank is about 20 ° C. According to the present invention, since fuel having a temperature higher than that of the fuel in the fuel tank is supplied to the fractionation unit, energy required for fractionation is compared with a mode in which the fuel pumped up from the fuel tank is immediately heated and fractionated. Can be reduced.

  In the first or second fuel fractionation device of the present invention, the fuel tank contains a fuel outlet for pumping fuel by the fuel feed pump, and fuel fractionally fractionated to the liquid phase side by the fractionation unit. A fuel return port for returning the fuel tank, wherein the fuel return port is disposed on one end side of the fuel tank, and the fuel outlet is disposed on the other end side of the fuel tank. . According to this aspect, since the fuel return port and the fuel outlet of the fuel (liquid phase fuel) fractionated to the liquid phase side in the fractionation unit are arranged apart from each other, the liquid phase returned to the fuel tank Fuel is not immediately pumped by the fuel feed pump. Therefore, liquid phase fuel, that is, fuel containing a large amount of high-boiling components can be prevented from being used for fractional distillation, so that vapor phase fuel can be fractionated efficiently in the fractionation section.

  In such a fuel tank, movement restriction between the fuel outlet and the fuel return port is restricted so that movement of fuel returned through the fuel return port to the fuel outlet side is restricted. Means may be provided (claim 5). By providing this movement restriction means, for example, even if an inertial force acts on the fuel tank due to an external factor such as driving of the vehicle, the fuel returned via the fuel return port easily moves to the fuel outlet side. Therefore, efficient fractionation can be sustained more.

  As described above, according to the present invention, the fuel feed pump, the pressurization pump, and the light fuel feed pump are arranged so as to be driven by a common drive shaft, or the fuel guided to the return passage is used. A fuel fractionation device for an internal combustion engine that has a fractionation unit that fractionates into a gas phase and a liquid phase, so that it is possible to improve the mountability at the same time as reducing costs, or to reduce the energy required for fractionation. Can be provided.

  FIG. 1 shows an embodiment in which a fuel fractionation device according to the present invention is applied to a diesel engine 1 as an internal combustion engine. As shown in this figure, an intake passage 2 and an exhaust passage 3 are connected to the engine 1. The intake passage 2 is provided with a compressor 4a of a supercharger 4 that uses exhaust energy to increase the intake pressure, and a throttle valve 5 for adjusting the intake air amount. The exhaust passage 3 is provided downstream of the exhaust manifold 3a. The exhaust gas purification device 6 disposed downstream of the turbine 4b and the turbine 4b of the turbocharger 4 disposed in the turbine 4 is provided. The exhaust purification device 6 is a known device in which an NOx storage reduction catalyst material is supported on a filter base material for collecting particulates, for example. The NOx occlusion is not limited as long as it can hold NOx.

  The engine 1 includes a fuel tank 7 that stores fuel (light oil), a feed passage 8 extending from the fuel tank 7, a supply pump unit 10 that pumps fuel from the fuel tank 7 to the common rail 9 through the feed passage 8, and a common rail 9. A plurality of (four in the figure) connected injectors 11 and return passages 12 for returning the fuel pumped from the fuel tank 7 to the fuel tank 7 are provided. Excess fuel such as fuel returned from the common rail 9 via the pipe 13 and the regulating valve 14 and fuel returned from the injector 11 via the pipe 15 and the check valve 16 are guided to the return passage 12.

  In the middle of the return passage 12, a fractionation passage 18 for guiding fuel to the fractionation section 17 is connected. A pressure adjusting valve 19 for adjusting the pressure balance is provided at a connection portion between the return passage 12 and the fractionation passage 18. A flow rate control valve 20 that controls the flow rate of the fuel guided to the fractionation unit 17 is provided in the fractionation passage 18 on the downstream side of the pressure regulating valve 19. The pressure adjustment valve 19 and the flow rate control valve 20 are respectively connected to an engine control unit (ECU) (not shown), and these valves 19 and 20 are configured as electromagnetic control valves whose opening degree can be controlled according to a predetermined command from the ECU. Has been. By appropriately controlling the opening degree of these valves 19 and 20, the amount of fuel introduced to the fractionator 17 can be adjusted. In addition, since the control method of the pressure control valve 19 and the flow control valve 20 is not directly related to the gist of the present invention, detailed description thereof is omitted here.

  As shown in detail in FIG. 2, the fractionation passage 18 passes through the fractionation section 18 a and the horizontal portion 18 b, reaches the branch point 18 c, and branches into the liquid phase passage 21 and the gas phase passage 22. While the fractionation section 18a is inclined with respect to the horizontal direction, it passes through the exhaust passage 3 on the downstream side of the exhaust purification device 6 obliquely. As a result, the fractionation section 18a is heated by the exhaust gas in the exhaust passage 3, and the fuel supplied from the return passage 12 to the fractionation section 17 is divided into the liquid phase fuel f1 and the gas phase fuel f2. The horizontal portion 18b and the branch point 18c are provided outside the exhaust passage 3, respectively. The fractionation passage 18 extends downward as a whole, and the liquid phase fuel f1 flows toward the branch point 18c by gravity.

  The liquid phase passage 21 has a gas phase stagnation portion 21a extending vertically downward from the branch point 18c and a passage portion 21b extending in the horizontal direction from the gas phase stagnation portion 21a. The inner diameter of the passage portion 21b is set slightly smaller than the inner diameter of the gas phase stagnation portion 21a. The downstream side of the passage portion 21b is connected to the fuel tank 7 (see FIG. 1).

  The gas phase passage 22 extends in the horizontal direction from the branch point 18c, and its downstream side is connected to a light fuel tank 23 (FIG. 1) for storing a light amount of fuel. f2 is guided to the light fuel tank 23 by the pressure in the fractionation passage 18 and the gas phase passage 22. As shown in FIG. 1, the fuel stored in the light fuel tank 23 is added into the exhaust passage 3 upstream of the exhaust purification device 6 by the addition injector 24. The supply of fuel to the addition injector 24 is performed by a supply pump unit 10 provided in the middle of the addition feed passage 25. Of the fuel pumped up from the light fuel tank 23 by the supply pump unit 10, excess fuel is guided to the light fuel return passage 26 and returned to the light fuel tank 23.

  As shown in detail in FIG. 3, the supply pump unit 10 includes a fuel feed pump 28 that pumps fuel from the fuel tank 7, a plunger pump 29 as a pressurizing pump that pressurizes the fuel pumped from the fuel feed pump 28, A light fuel feed pump 30 is provided for pumping fuel from the light fuel tank 23 and feeding it to the injector 24 for addition. These pumps 28 to 30 are arranged so as to be driven by a common drive shaft 31 that rotates about an axis CL. The rotation of the crankshaft (not shown) of the engine 1 is transmitted to the drive shaft 31 via transmission means such as a gear.

  The supply pump unit 10 includes a main housing 33 in which a pump chamber 32 of the plunger pump 29 is formed, and a feed pump housing 34 attached to the main housing 33. In the pump chamber 32, a pair of plungers 35, 35 disposed opposite to each other with the drive shaft 31 interposed therebetween are disposed, and these plungers 35, 35 are moved up and down by an outer cam 36 attached to the drive shaft 31. As a result, the fuel in the pump chamber 32 is pumped to the common rail 9 through the delivery valve 37 and the feed passage 8 at a high pressure of about 180 MPa.

  A pump chamber 38 of the fuel feed pump 28 and a pump chamber 39 of the light fuel feed pump 30 are formed in the feed pump housing 34, and these pump chambers 38 and 39 are partitioned by a partition wall 40. The pump chamber 38 accommodates the rotor 41 of the fuel feed pump 28, and the pump chamber 39 accommodates the rotor 42 of the light fuel feed pump 30. The rotors 41 and 42 are respectively attached to the drive shaft 31, and these rotate in the pump chambers 38 and 39 as the drive shaft 31 rotates.

  FIG. 4 is an explanatory view schematically showing the inside of the fuel feed pump 28. As shown in this figure, the rotor 41 is provided eccentrically with respect to the pump chamber 38, and a plurality (eight in the figure) of vanes 43 are attached to the rotor 41 so as to be movable in the groove 44. Yes. As the rotor 41 rotates in the direction of the arrow in the figure, each vane 43 is pushed out of the rotor 41 by centrifugal force. Therefore, the fuel guided from the inlet 45 to the pump chamber 38 and sandwiched between the vanes 43 is compressed, and then sent to the pump chamber 32 of the plunger pump 29 via the communication passage 46 (see also FIG. 3). It is. The pressure that the fuel feed pump 28 sends to the plunger pump 29 is about 0.7 MPa. A passage (not shown) for guiding excess fuel to the return passage 12 is connected midway in the communication passage 46, and a regulating valve (not shown) is provided in this passage. The fuel that cannot be fed into the pump chamber 32 of the plunger pump 29 by the fuel feed pump 28 is guided to the return passage 12 through this regulating valve.

  As shown in FIG. 5, the light fuel feed pump 30 also has the same configuration as that of FIG. The fuel pumped from the light fuel tank 23 to the pump chamber 39 through the inlet 47 is compressed in the pump chamber 39 and discharged from the outlet 48 at a pressure of about 0.7 MPa. The discharged fuel is sent to the addition injector 24 through the addition feed passage 25 (see also FIG. 1). In FIG. 5, reference numeral 49 denotes a vane, and reference numeral 50 denotes a groove.

  Returning to FIG. 1, the fuel tank 7 is provided with a fuel outlet 51 for pumping up the fuel in the tank and a fuel return port 52 for returning the liquid phase fuel. The fuel outlet 51 is connected to the feed passage 8 and the fuel return port 52 is connected to the liquid phase passage 21 (passage portion 21b). The fuel outlet 51 and the fuel return port 52 are disposed at both ends of the fuel tank 7 so as to be separated from each other.

  A convex portion 7 a that protrudes vertically upward is formed between the fuel outlet 51 and the fuel return port 52, that is, at the center of the fuel tank 7 so as to cross the fuel tank 7. Further, a partition wall 53 is attached to the upper side of the convex portion 7 a so as to cross the fuel tank 7. The convex portion 7a and the partition wall 53 function as movement restriction means for restricting the liquid phase fuel returned to the fuel tank 7 from moving to the fuel outlet 51 side. In order to exert the effect as the movement restricting means, it is not always necessary to provide both the convex portion 7 a and the partition wall 53 as shown in FIG. 1, and either one of them may be provided in the fuel tank 7.

  The present invention is not limited to the above embodiment, and may be implemented in various forms. The fractionation section 18a may be provided so as to be able to exchange heat with an appropriate position of the exhaust passage 3. For example, the fractionation section 18a may be provided so as to pass through the exhaust manifold 3a, or arranged so as to be along the outside of the exhaust passage 3. May be. Further, the fractionation method is not limited to the form using the heat energy of the exhaust, and may be a form in which fractionation is performed using a heating means such as a heater.

  Further, as long as the fuel feed pump, the pressurization pump, and the light fuel feed pump are each driven by a common drive shaft, the present invention is not limited to the above-described embodiment. For example, an inner gear type pump may be used as the fuel feed pump or the light fuel feed pump. Moreover, each pump may be integrated by the common housing, and the housing may be isolate | separated for every pump.

  The supply destination of the light fuel is not particularly limited, and may be in the cylinder of the engine 1. In this case, a pump capable of pumping about 180 MPa may be appropriately used as the light fuel feed pump.

The figure which shows one Embodiment of the fractionation apparatus of this invention. The figure which expanded and showed the fractionation part of FIG. The figure which showed the detail of the supply pump unit. The figure which showed the inside of the fuel feed pump typically. The figure which showed the inside of the light fuel feed pump typically.

Explanation of symbols

1 Diesel engine (internal combustion engine)
7 Fuel tank 7a Convex part (movement restriction means)
9 Common rail 12 Return passage 17 Fractionation section 28 Fuel feed pump 29 Plunger pump (pressure pump)
30 Light fuel feed pump 31 Drive shaft 50 Fuel outlet 51 Fuel return 52 Bulkhead (movement limiting means)

Claims (4)

A fractionation unit for fractionating fuel into a gas phase and a liquid phase, a fuel feed pump for pumping fuel from a fuel tank, a pressure pump for pressurizing fuel pumped by the fuel feed pump, and the fractionation unit A light fuel feed pump for supplying the fuel fractionated to the gas phase side to a predetermined supply destination,
A fuel fractionating device for an internal combustion engine, wherein the fuel feed pump, the pressurizing pump, and the light fuel feed pump are arranged to be driven by a common drive shaft.   A fuel feed pump for pumping fuel from a fuel tank, a pressure pump for pressurizing fuel pumped by the fuel feed pump, a common rail for accumulating fuel pressurized by the pressure pump, and the fuel tank from the common rail A fuel fractionating device for an internal combustion engine, comprising: a return passage for returning fuel to the fuel; and a fractionation section for fractionating the fuel guided to the return passage into a gas phase and a liquid phase. The fuel tank is provided with a fuel outlet for pumping fuel with the fuel feed pump, and a fuel return port for returning the fuel fractionally fractionated to the liquid phase side in the fractionator,
3. The fuel fractionation of an internal combustion engine according to claim 1, wherein the fuel return port is disposed on one end side of the fuel tank, and the fuel outlet is disposed on the other end side of the fuel tank. apparatus. The fuel tank has a movement limiting means between the fuel outlet and the fuel return port so that movement of the fuel returned through the fuel return port to the fuel outlet side is restricted. The fuel fractionation device for an internal combustion engine according to claim 3, wherein the fuel fractionation device is provided.

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