JP2005127196A - Fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device enabling the adjustment of ignition timing by pre-mixed combustion. <P>SOLUTION: In this fuel injection device, the mixed fluid of light oil and water is injected and supplied into a combustion chamber 106. The fuel injection device comprises light oil pressurizing means Pf and Rf pressurizing the light oil to a specified pressure, water pressurizing means Pw and Rw pressurizing water capable of storing heat energy by latent heat to a specified pressure, and a mixing means 50 mixing a high-pressure light oil with a specified pressure and a high-pressure water with a specified pressure into a mixed fluid at a specified mixing ratio. The mixing means 50 desirably comprises a porous body 51 separating the high-pressure light oil from the high-pressure water and dispersing them. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel injection device, and is suitably applied to a fuel injection device that injects high-pressure fuel or the like into an internal combustion engine such as a diesel engine.

As a fuel injection device, for example, as a fuel injection device for a diesel engine, there is a fuel injection device that injects fuel into a combustion chamber, mixes the injected fuel and air, and causes self-ignition. In recent years, diesel engines have been required to reduce harmful components such as NO _x and black smoke in exhaust gas due to environmental problems caused by exhaust gas discharged from the engine. NO _X and black smoke are in a trade-off relationship, and simultaneous reduction is difficult.

The techniques according to the disclosure of Patent Document 1, to realize a premixing combustion using a fitting technique by large amounts EGR, swirl, and the injection timing delay, thereby achieving simultaneous reduction of the NO _X and black smoke.
JP-A-8-86251

  However, the conventional technique has a problem that fuel consumption is deteriorated because combustion occurs at a time much later than TDC.

  In order to achieve both improvement in fuel consumption and reduction in exhaust gas, it is necessary to perform premix combustion near TDC. However, since the in-cylinder temperature suddenly increases in the latter half of the compression stroke, the fuel injected earlier ignites before reaching TDC. When trying to perform premixed combustion in a conventional injection system, there is a problem that it is difficult to control the ignition timing.

  The present invention has been made in consideration of such circumstances, and an object thereof is to provide a fuel injection device capable of adjusting the ignition timing by premixed combustion.

  Another object is to provide a fuel injection device capable of adjusting the ignition timing by premixed combustion and reducing exhaust gas.

  According to the first aspect of the present invention, in the fuel injection device for injecting and supplying a mixed fluid of fuel and functional fluid to the combustion chamber, the fuel pressurizing means for pressurizing the fuel to a predetermined pressure, and the functional fluid is thermal energy. A fluid pressurizing unit that pressurizes the functional fluid to a predetermined pressure, and a high-pressure fuel having a predetermined pressure and a high-pressure functional fluid having a predetermined pressure are mixed into a mixed fluid in a predetermined ratio. And a mixing means.

  According to this, in order to inject and supply a mixed fluid of fuel and functional fluid to the combustion chamber, the fuel pressurizing means for pressurizing to a predetermined fuel pressure and the fluid pressurizing means for pressurizing to the predetermined functional fluid pressure are provided. Have. A functional fluid is a fluid capable of storing thermal energy, such as a fluid having a boiling point lower than that of fuel. Further, since the mixing means capable of mixing these high-pressure fuel and high-pressure fluid is provided, it is possible to mix the high-pressure fuel and high-pressure fluid, for example, at a predetermined mixing ratio and inject and supply them to the combustion chamber. Therefore, even if fuel is injected early for premix combustion near TDC, the timing (ignition timing) when the injected fuel reaches the in-cylinder temperature by ignition due to the latent heat of a fluid such as water is delayed. Can do. Therefore, the ignition timing can be adjusted.

  According to claim 2 of the present invention, the mixing means has a porous body for isolating and dispersing between the high-pressure fuel and the high-pressure functional fluid.

  According to this, since the porous body has a plurality of relatively thin holes penetrating between both end faces, so-called through pores, for example, the high-pressure fuel and the high-pressure fluid respectively disposed between the both end faces are isolated, for example, A high-pressure functional fluid having a predetermined pressure higher than that of the high-pressure fuel can permeate through the through-holes and be dispersed in the high-pressure fuel.

  According to claim 3 of the present invention, the porous body has a structure in which the high-pressure fuel is guided to the inside and the high-pressure functional fluid is guided to the outer periphery.

  Since the porous body is generally formed from metal ceramics such as copper obtained by sintering and molding metal particles or non-metal particles, or non-metallic ceramics such as alumina or glass, it is relatively weak against tensile stress compared to compressive stress. .

  On the other hand, in the fuel injection device according to claim 3, because of the structure for guiding the fluid mixed with the fuel to the outer periphery of the porous body, for example, when changing the mixing ratio by changing a predetermined functional fluid pressure, Since compressive stress acts on the porous body, it is easy to ensure the structural strength of the porous body. Therefore, for example, the size of the mixing means, that is, the fuel injection device can be reduced.

  According to claim 4 of the present invention, the porous body is formed in a plurality of flat plates, and adjacent plates are alternately formed and stacked so that communication holes do not overlap. It is characterized by.

  The means for forming the mixing ratio according to the functional fluid pressure using the porous body is not limited to the one in which the size of the through-hole is formed to a substantially uniform predetermined size by the material to be sintered, In the porous body formed in the flat plate, the layers may be alternately stacked so that the communication holes formed in the adjacent plates do not overlap each other. Thereby, it is possible to form the mixing ratio according to the functional fluid pressure with the combination of the laminated plates without depending on the material forming the through pores of the porous body.

  According to claim 5 of the present invention, the porous body is made of shirasu porous glass.

  According to this, since the porous body is made of shirasu porous glass, a plurality of through-holes can be precisely formed. Moreover, this shirasu porous glass can form the magnitude | size of a through-pore in a comparatively wide range. Therefore, it is possible to use a porous body, that is, a mixing means formed in a predetermined through-hole size in accordance with required injection characteristics, for example, the number of injections per combustion.

  According to claim 6 of the present invention, the needle seat having a contact portion at the tip, the guide hole for fitting the needle so as to be reciprocally slidable in the axial direction, and the valve seat contacting and separating between the contact portion. And a mixing means is provided in the nozzle body or the injection valve.

  Compared to the conventional mixing means for mixing the fuel and the fluid separately from the nozzle body and the inside of the injection valve, it is easy to form a mixing ratio different for each injection. Further, during one combustion (during multistage injection), the mixing ratio for each injection can be changed.

  According to the seventh aspect of the present invention, the fluid valve has a fluid valve for circulating and blocking the high-pressure functional fluid to the mixing means, and the pressure of the high-pressure fuel, the pressure of the high-pressure functional fluid, and the valve opening period of the fluid valve Control means for performing adjustment control and control for causing the mixed fluid to be ejected and stopped by moving the needle up and down to separate and seat the contact portion and the valve seat. .

  According to this, the control means controls the opening period of the fluid valve for circulating and shutting off the high-pressure functional fluid from the fluid pressurizing means to the mixing means, and the predetermined functional fluid pressure pressurized by the fluid pressurizing means. Therefore, for example, by changing the mixing ratio quickly within a short valve opening period by making the predetermined functional fluid pressure relatively high, or by setting the valve opening period relatively long to form a stable mixing ratio, etc. The degree of freedom related to the ratio setting can be improved.

  According to claim 8 of the present invention, the functional fluid is water, and the predetermined water pressure is higher than the predetermined fuel pressure.

As functional fluids by use of water, by steam formation, since it is diluted with cooling of the reaction zone where there is a mixture of fuel and air, it can be reduced in NO _X. Further, atomization of fuel spray can be achieved by so-called micro explosion caused by volume expansion from water to water vapor, so that PM can be reduced.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments in which a fuel injection device of the present invention is embodied will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a configuration diagram showing the overall configuration of the fuel injection device of the present embodiment. FIG. 2 is a schematic cross-sectional view showing the configuration of the injector in FIG. 3A and 3B are views showing the fuel injection nozzle in FIG. 2, in which FIG. 3A is a sectional view, and FIG. 3B is a perspective view showing a porous body in FIG. 3A. FIG. 4 is a flowchart showing a control process that is executed in the ECU shown in FIG. 1 to perform injection control of a mixed fluid of fuel and water. FIG. 5 is a graph showing characteristics of an injection rate, a heat generation rate, and an in-cylinder temperature with respect to a crank angle in the fuel injection device of the present embodiment. FIG. 6 is a combustion pattern diagram of a diesel engine in the fuel injection device of the present embodiment.

  As shown in FIG. 1, the fuel injection device includes a high-pressure supply pump (hereinafter referred to as a light oil pump) Pf that pressurizes and discharges light oil as fuel, and an accumulator that stores light oil discharged from the light oil pump Pf in a high-pressure state. Chamber (hereinafter referred to as a light oil common rail) Rf, a high-pressure supply pump (hereinafter referred to as a water pump) Pw that pressurizes and discharges water as a functional fluid, and water discharged from the water pump Pw is in a high-pressure state Are provided for each cylinder of a pressure accumulating chamber (hereinafter referred to as a water common rail) Rw and a multi-cylinder (only one cylinder is shown in FIG. 1) diesel engine (hereinafter referred to as an engine) 100, a light oil common rail Rf and a water common rail Rw. A fuel injection valve (hereinafter referred to as an injector) I for injecting and supplying a mixed fluid of high pressure fuel and high pressure water stored in the cylinder to the combustion chamber 106 of the cylinder; Control means for driving and controlling the device constituting the engine 100 including a system (hereinafter, referred to as ECU) and a 200. The injector I is attached to the cylinder head 102. Specifically, the combustion chamber 106 is partitioned by an inner peripheral surface of the cylinder block 101, an inner peripheral surface of the cylinder head 102, and an upper end surface having a cavity of the piston 104, and the injector I is disposed facing the combustion chamber 106. Then, fuel consisting of at least one of light oil and water is directly injected into the combustion chamber 106. The ECU 200 is a control device that controls the engine 100, and is an electronic control unit that electronically controls a plurality of injectors I and the like, not limited to the control of the light oil pump Pf and the water pump Pw. The injector I provided for each cylinder is connected to common rails Rf and Rw as pressure accumulating chambers common to the respective cylinders via supply pipes 18 and 19, respectively. The injection of the mixed fluid from the injector I to each combustion chamber 106 of the engine 100 is controlled by ON / OFF of the electromagnetic valve Bi for injection control, and while the electromagnetic valve Bi is open, each common rail Rf, Rw Fuel and water are injected into the engine 100 by the injector I.

  In the following description, for convenience of explanation, the engine 100 is assumed to be four cylinders, and the cylinder shown in FIG. 1 will be described.

  A light oil pump Pf and a water pump Pw are connected to the common rails Rf and Rw via supply pipes 18 and 19, respectively. Each of the light oil pump Pf and the water pump Pw includes a feed pump, a pressure feed system member, and pressure feed metering valves P2f and P2w (not shown). The light oil pump Pf pressurizes low pressure light oil sucked through a fuel tank (hereinafter referred to as a light oil tank) Tf to a high pressure, and the light oil in the light oil common rail Rf becomes a predetermined high pressure so-called common rail pressure (hereinafter referred to as light oil common rail pressure). Control. The water pump Pw pressurizes low-pressure water sucked through a functional fluid tank (hereinafter referred to as a water tank) Tw to a high pressure, and the water in the water common rail Rw is set to a predetermined common rail pressure (hereinafter referred to as water common rail pressure). Control.

  The ECU 200 has a general hardware configuration having a CPU or the like, and sensor signals of various sensors S1f, S1w, S2, and S3 are input to the ECU 200. Based on the input of these sensor signals and the like, the ECU 200 supplies and stops water from the injector I, the light oil pump Pf, the water pump Pw, and the water common rail Pw to the injector I (hereinafter referred to as a water valve) Bw. Control signals are respectively output to control the injector I, the light oil pump Pf, the water pump Pw, and the water valve Bw. The ECU 200 receives information related to the operating state of the engine 100, for example, from an engine speed sensor S2, a cylinder discrimination sensor S3, and the like serving as a rotational speed detecting means. In addition, pressure sensors S1f and S1w as pressure detecting means for detecting the light oil common rail pressure and the water common rail pressure are disposed on the common rails Rf and Rw, respectively, and thereby the ECU 200 has information on the light oil common rail pressure and the water common rail pressure. Is entered. The ECU 200 determines an optimal injection timing and injection amount (injection period) based on these pieces of information, and outputs a control signal to the injection control electromagnetic valve Bi.

  The ECU 200 calculates a target common rail pressure to be stored in the common rail Rf and a target light hydraulic pressure feed amount of the high pressure light oil to be supplied from the light oil pump Pf to the common rail Pf from the information related to the operating state of the engine 100. The ECU 200 controls the pressure feed amount adjustment valve P2f based on the target light hydraulic pressure feed amount, thereby controlling the pressure feed amount, that is, the suction amount of the light oil pump Pf. Further, the ECU 200 determines the target mixture ratio of the light oil and water in the mixed fluid injected from the injector I, the target common rail pressure, and the target of the high-pressure water supplied from the water pump Pw to the common rail Pw from the information regarding the operating state of the engine 100. Calculate the water pumping amount. The ECU 200 controls the pumping amount metering valve P2w based on the target water pumping amount, thereby controlling the pumping amount of the water pump Pw, that is, the suction amount.

  Next, the configuration of the injector I will be described with reference to FIGS. As shown in FIG. 2, the injector I includes a needle 31, a nozzle body 11, an injection control electromagnetic valve Bi, and a mixing device 50. As shown in FIGS. 2 and 3A, the needle 31 is assembled inside the nozzle body 11 so as to be slidable in the axial direction. The injection control electromagnetic valve Bi may be any driving means that raises and lowers the needle to seat and separate the needle 31 from the nozzle body 31, and is added to one of the shaft ends of the needle 31. The present invention is not limited to the flow rate control valve for controlling the working fluid pressure of the working fluid, and may be an electromagnetic drive device that directly drives the needle 31 or a piezo actuator using a piezoelectric element that expands and contracts by energization.

  In the following, in this embodiment, the drive means for moving the needle up and down will be described with an injection control electromagnetic valve Bi that controls the working fluid pressure of the working fluid applied to one of the shaft ends of the needle 31. .

  As shown in FIG. 3A, the nozzle body 11 is a substantially hollow cylindrical body having a bottom, and includes a guide hole 12, a valve seat 13, an injection hole (hereinafter referred to as an injection hole) 41, a sac, and the like. Part 15 is formed. The guide hole 12 extends in the axial direction inside the nozzle body 11, one end thereof is connected to the open end (the upper end in FIG. 3A) of the nozzle body 11, and the other end is on the valve seat 13. Connected to. The inner wall of the guide hole 12 is formed with substantially the same inner diameter from the open end of the nozzle body 11 to the vicinity of the bottomed valve seat 13.

  As shown in FIG. 3A, the valve seat 13 has a truncated cone surface, one end on the large diameter side continues to the guide hole 12, and the other end on the small diameter side is connected to the sack portion 15. . A contact portion 36 of the needle 31 is disposed on the valve seat 13 so as to be able to contact and separate. The contact portion 36 is theoretically in the shape of a circle. The sack portion 15 is a sack hole formed in a bag shape with a small space volume on the tip side of the nozzle body 11. The opening side of the sack hole continues to the small diameter side of the valve seat 13. Here, the sac portion 15 constitutes a sac chamber having a bag-shaped predetermined space volume.

  As shown in FIGS. 2 and 3A, the nozzle hole 41 is formed as a passage communicating with the sack portion 15 of the nozzle body 11 through the inside and outside of the nozzle body 11.

  As shown in FIG. 8, the fuel reservoir 16 is formed in an annular recess in the middle of the inner wall forming the guide hole 12 of the nozzle body 11. A fuel supply hole 17 to which light oil and water are supplied from the outside is connected to the fuel reservoir 16. A mixing means (hereinafter referred to as an emulsifying device) 50 is provided on the upstream side of the flow of the fuel supply hole 17.

  The emulsification device 50 includes a porous body 51 as shown in FIG. The porous body 51 has a large number of relatively thin holes (hereinafter referred to as through-holes) (not shown) penetrating between both ends (the left-right direction in FIG. 3A). As shown in FIG. 3B, the porous body 51 is a substantially cylindrical body, and high pressure light oil is guided to the inner circumference 51a via the supply pipe 18, and the outer circumference 51b The high-pressure water is guided through the supply pipe 19. The porous body 51 can mix high-pressure water and high-pressure light oil. Many through-holes can disperse high-pressure water into high-pressure gas oil based on a predetermined water pressure.

  Here, the porous body 51 constitutes a mixing means that can separate and disperse the high-pressure light oil and the high-pressure water.

  The porous body 51 is made of, for example, metal ceramics such as copper obtained by sintering and molding metal particles or nonmetal particles, or nonmetal ceramics such as alumina or glass. In addition, the porous body 51 demonstrated by this embodiment below shall be formed from shirasu porous glass.

  Shirasu porous glass has a large number of through pores of uniform size, that is, precisely controlled through pores, as a feature. In addition, since Shirasu porous glass can be formed in a relatively wide range of through-hole sizes, there is a degree of freedom in designing through-holes.

  As shown in FIG. 2, the high-pressure fuel led to the supply pipe 18 flows into the emulsifying device 50 and flows into the pressure control chamber 40. A leak pipe 41 is connected to the downstream side of the pressure control chamber 40, and an injection control electromagnetic valve Bi is arranged in the middle of the leak pipe 41. The downstream side of the leak pipe 41 is connected to a supply pipe 18 between the light oil pump Pf and the light oil common rail Rf.

  The needle 31 has a solid cylindrical shape as a basic shape, and includes a large-diameter cylindrical portion 32, a small-diameter cylindrical portion 34, a truncated cone portion 35, and a conical portion 37, as shown in FIG.

  The large-diameter cylindrical portion 32 has an outer shape with substantially the same diameter, and is loosely fitted into the guide hole 12 via a predetermined clearance. Therefore, the large diameter cylindrical portion 32 can reciprocate in the axial direction. The small diameter cylindrical portion 34 extends in the axial direction from the vicinity of the fuel reservoir 16 to the vicinity of the valve seat 13. The outer diameter of the small diameter cylindrical portion 34 is formed smaller than the inner diameter of the guide hole 12. A gap between the small diameter cylindrical portion 34 and the inner wall of the guide hole 12 becomes a fuel passage through which light oil and water flow.

  One end portion of the truncated cone portion 35 is continuous with the small-diameter cylindrical portion 34, and the other end portion is continuous with the conical portion 37 via the circular contact portion 36. A connecting portion between the truncated cone portion 35 and the conical portion 37 is a circle, and this circle portion becomes a contact portion when the valve is closed. The conical portion 37 has an inclination angle larger than the inclination angle of the valve seat 13. This is because the contact portion 36 and the valve seat 13 can be contacted when the valve is closed to ensure oil tightness. The tip of the conical portion 37 is a position facing the sack portion 15 when the valve is closed. The needle 31 and the nozzle body 11 constitute an injection valve.

  Next, the operation of the present embodiment having the above-described configuration will be described. The light oil pump Pf sucks light oil from the light oil tank Tf and pumps the high pressure light oil to the light oil common rail Rf. The pumped high-pressure light oil is accumulated at a predetermined light oil common rail pressure by the light oil common rail Rf. High-pressure light oil having a predetermined light oil common rail pressure is supplied to the injector I via the supply pipe 18. The high-pressure light oil supplied into the injector I is guided to the inner periphery 51 a of the porous body 51 of the emulsifying device 50 and also to the pressure control chamber 41. The high pressure light oil guided to the inner periphery 51 a is guided to the fuel reservoir 16 and the guide hole 12 through the fuel supply hole 17. At this time, since the same predetermined light oil common rail pressure is applied to the pressure control chamber 41 and the fuel reservoir 16, the needle 31 is seated on the valve seat 13 and closed. When the injection control electromagnetic valve Bi is driven to open, the pressure in the pressure control chamber 41 decreases. When the pressure in the pressure control chamber 41 decreases and the pressure in the fuel reservoir 16 becomes larger than the pressure in the pressure control chamber 41, the needle 31 is pushed upward in FIG. Separate from the valve seat 13. As a result, the high pressure fuel passes through the fuel passage formed in the gap between the small-diameter cylindrical portion 34 and the guide hole 12, passes through the gap (corresponding to the lift amount) separated from the valve seat 13, and the high-pressure fuel Room 15) The fuel is injected into the combustion chamber 106 through the injection hole 41 opened in the sac chamber 15. On the other hand, when the injection control electromagnetic valve Bi is driven to close, the pressure in the pressure control chamber 41 becomes the same as the pressure in the fuel reservoir 16. As a result, the needle 31 is pushed downward in FIG. 3A, the contact portion 36 of the needle 31 is seated from the valve seat 13, and the injection is stopped.

  The water pump Pw sucks water from the water tank Tw and pumps high-pressure water to the water common rail Rw. The pumped high-pressure water is accumulated in the predetermined water common rail pressure by the water common rail Rw (predetermined water common rail pressure> predetermined light oil common rail pressure). When the water valve is driven to open, the high-pressure water having a predetermined water common rail pressure is supplied to the injector I via the supply pipe 18 and is guided to the outer periphery 51b of the porous body 51 of the emulsifying device 50. High-pressure water having a predetermined common rail pressure higher than that of the high-pressure light oil permeates through the through pores of the porous body 51 and is dispersed into the high-pressure light oil. As a result, the porous body 51 can mix high-pressure water and high-pressure light oil at a predetermined mixing ratio in accordance with a predetermined water common rail pressure. The predetermined mixing ratio can be adjusted by the opening period of the water valve Bw and the predetermined water common rail pressure.

  Next, operations relating to the mixing ratio of the mixed fluid of light oil and water injected from the injector I and the injection characteristics of the mixed fluid will be described with reference to FIGS. 4, 5, and 6. As shown in FIG. 4, in S401 (S is a step), the ECU 200 receives signals output from the engine speed sensor S2, the cylinder discrimination sensor S3, and the like, and reads the operating state of the engine 100. In addition, it is preferable to receive the signals of the water common rail pressure and the light oil common rail pressure output from the pressure sensors S1f and S1w as signals indicating the operation state.

  In S402, the mixing ratio of light oil and water is calculated from the operating state of the engine 100 based on predetermined map information of the ECU 200, and the process proceeds to S403. It should be noted that a predetermined mixing ratio is set within the premixed combustion region shown in the graph of load and engine speed in FIG. In the diffusion combustion zone, normal fuel injection with 100% light oil and 0% water is assumed. Specifically, in a relatively high load range of low and medium speed, 100% light oil is injected into the combustion chamber 106. In a relatively low load range of low and medium speed, a mixed fuel having a predetermined mixing ratio is injected into the combustion chamber 106.

  In S403, the intake amount for making the water common rail pressure a predetermined pressure, that is, the target water pressure feed amount, is calculated from the mixing ratio obtained in S402, and the process proceeds to S404. Note that the intake amount is preferably determined from the mixing ratio and the injection characteristics (for example, whether the injection is multistage injection such as pilot injection or normal injection). In multi-stage injection in which injection is performed multiple times during one combustion, the water valve opening period for achieving a predetermined mixing ratio can be shortened by increasing the intake amount and increasing the water common rail pressure. Improvement can be achieved.

  In S404, the valve opening period of the water valve Bw is calculated according to the injection characteristics determined from the operating state read in S401 and the mixing ratio obtained in S402, and the process proceeds to S405. For example, as shown in the graph of FIG. 5, when the injection characteristic is pilot injection, the first injection is 100% water and the main injection is 100% light oil, the ECU 200 sets the water valve Bw before the main injection from the map information. Set the valve closing period to close. The main injection is not limited to 100% light oil, but may be a mixed fluid of light oil and water, so-called emulsion fuel.

  In S405, the target light oil common rail pressure required from the operation state read in S401 is obtained, the target light oil pressure feed amount, that is, the intake amount corresponding to the target light oil common rail pressure is calculated from the map information, and the process proceeds to S406.

  In S406, the target injection amount required in the operation state is calculated, the valve opening period of the injection control electromagnetic valve Bi is calculated from the map information based on the target injection amount and the target light oil common rail pressure, and the process proceeds to S407.

  In S407 and S408, a mixed fluid of light oil and water is injected from the injector I into the combustion chamber 106 in accordance with required injection characteristics. In S407, by controlling the water pump Pf and the water valve Bw, the predetermined water common rail pressure applied to the outer periphery 51b of the porous body 51 of the emulsifying device 50 and the period during which the pressure is applied are controlled. On the other hand, a predetermined light oil common rail pressure applied to the inner periphery of the porous body 51 is controlled by controlling the light oil pump Pf. Since the predetermined water common rail pressure is higher than the predetermined light oil common rail pressure, the high pressure water with the predetermined water common rail pressure permeates through the many through-holes formed in the porous body 51 into the high pressure light oil with the predetermined light oil common rail pressure. Dispersed and mixed.

  Since the through-holes are uniform in size, light oil and water can be mixed at a predetermined mixing ratio according to a predetermined water common rail pressure.

  Furthermore, since the through pores have a relatively small pore size (about 0.2 to 20 μm), high-pressure water permeates through the through-pores and becomes fine water droplets and is dispersed in the high-pressure gas oil. As a result, high-pressure water can be emulsified and mixed with high-pressure gas oil via the emulsifying device 50.

  Furthermore, it is preferable to add about 2% of a surfactant in water or light oil. Water can be stably dispersed in the form of particulates in light oil.

  In S408, the valve opening period of the injection control electromagnetic valve Bi is controlled in accordance with the required injection characteristics.

  Here, the light oil pump Pf and the light oil common rail Rf constitute light oil pressurizing means for pressurizing to a predetermined light oil pressure. The water pump Pw and the water common rail Rw constitute water pressurizing means for pressurizing to a predetermined water pressure. The emulsifying device 50 constitutes a mixing means. The needle 31 and the nozzle body 11 constitute an injection nozzle N. Water is a functional fluid capable of storing thermal energy, and heat energy generated by, for example, adiabatic compression is absorbed by latent heat.

  Next, functions and effects of the present embodiment will be described. (1) Light oil pressurizing means Pf that pressurizes high pressure light oil at a predetermined light oil pressure in order to inject and supply a mixed fluid of light oil and water to the combustion chamber 106. Rf and water pressurizing means Pw and Rw for pressurizing high-pressure water having a predetermined water pressure. Further, since the high-pressure gas oil and the high-pressure water have mixing means 50 capable of mixing based on a predetermined pressure of the high-pressure water, the high-pressure fuel and the high-pressure fluid are mixed at a predetermined mixing ratio and supplied to the combustion chamber 106 for injection. Is possible. Therefore, heat energy generated with so-called adiabatic compression during the compression stroke of engine 100 can be absorbed by a heat storage function such as latent heat of the injected water itself. Therefore, even if light oil is injected early for premix combustion near TDC, the timing (ignition time) when the injected light oil reaches the in-cylinder temperature at which it is ignited can be delayed by the latent heat of water (see FIG. 5). Therefore, the ignition timing can be adjusted. In FIG. 5, the broken line conventional injection system is as shown in FIG. 8.

  (2) The emulsifying device 50 as a mixing means has a porous body 51 that can separate and disperse between high pressure water and high pressure light oil. Since the porous body 51 has a large number of through pores that penetrate between both end faces, the high-pressure light oil and the high-pressure water respectively disposed between the both end faces are isolated, or the high-pressure water having a pressure higher than that of the high-pressure light oil is Based on a predetermined water common rail pressure, it can permeate through the through-holes and be dispersed or mixed into the high-pressure gas oil.

  (3) Since the porous body is generally formed from metal ceramics such as copper obtained by sintering and molding metal particles or non-metal particles, or non-metal ceramics such as alumina or glass, it is tensile compared to compressive stress. Relatively weak to stress. On the other hand, in the present embodiment, the porous body 51 is a substantially cylindrical body, and is configured such that high-pressure light oil is guided to the inner periphery 51a and high-pressure water is guided to the outer periphery 51b. . Accordingly, since water is mixed with light oil in a wide mixing ratio range, when the mixing ratio is changed by changing a predetermined water common rail pressure, a compressive stress acts on the porous body 51. Ensuring the structural strength of the body 51 is facilitated. Therefore, for example, the size of the emulsifying device 50, that is, the fuel injection device can be reduced.

  (4) Since the porous body 51 is made of shirasu porous glass, a plurality of through-holes can be precisely formed. Moreover, this shirasu porous glass can form the magnitude | size of a through-pore in a comparatively wide range. Therefore, the porous body 51, that is, the mixing means 50 formed in a predetermined through-hole size can be used according to the required injection characteristics, for example, the number of injections per combustion.

  (5) Since the mixing means 50 can be formed in the nozzle body 11, the mixing means is compared with the valve seat 13 of the injection nozzle N as compared with the conventional mixing means arranged separately from the nozzle body. It can be brought close to the contact portion 36, and therefore, it becomes easy to form a different mixing ratio for each injection. Further, during one combustion (during multistage injection), the mixing ratio for each injection can be changed (see FIG. 5).

  (6) The ECU 200 performs injection and injection stop of the injection nozzle N and controls the valve opening period of the water valve Bw and the predetermined water common rail pressure, so that, for example, the predetermined water common rail pressure is made relatively high. Thus, the degree of freedom related to the setting of the mixing ratio, such as changing the mixing ratio quickly within a short valve opening period of the water valve Bw or forming a stable mixing ratio by setting the valve opening period of the water valve Bw relatively long, etc. Can be planned.

(7) Using water as a fluid to be mixed with light oil, a predetermined water common rail pressure is formed higher than a predetermined light oil common rail pressure. For this reason, water is effective as a functional fluid for storing heat energy. By using water as the functional fluid, it is possible to dilute and cool the reaction zone where there is a mixture of light oil and air by forming water vapor, so that NO _X that is a harmful component of exhaust gas can be reduced. In addition, fuel spray atomization can be achieved by so-called micro-explosion caused by volume expansion from water to water vapor, so that PM which is a harmful component of exhaust gas can be reduced.

  (8) In the graph of load and engine speed, as shown in FIG. 6, the premixed combustion zone can be expanded to the high load side as compared to the premixed combustion zone of the conventional injection system (see FIG. 9). Is possible. As a result, premixed combustion can be performed in a mode region that was difficult in a conventional combustion system.

(Second Embodiment)
Hereinafter, other embodiments to which the present invention is applied will be described. In the following embodiments, the same or equivalent components as those in the first embodiment are denoted by the same reference numerals, and description thereof will not be repeated.

  In the second embodiment, as shown in FIG. 7, the porous body 151 is formed on a plurality (six in FIG. 7A) of flat plates 151a and 151b and adjacent plates 151a and 151b ( In FIG. 7B, the communication holes are formed differently and stacked so that the communication holes do not overlap. 7A and 7B are diagrams showing a mixing apparatus according to the present embodiment, in which FIG. 7A is a schematic perspective view, and FIG. 7B is a stack of porous bodies in FIG. 7A. It is an expanded view which shows adjacent plates among other plates.

  As shown in FIG. 7B, each plate 151a, 151b is formed with a communication hole penetrating in the vertical direction of FIG. Further, the plates 151a and 151b are stacked in a staggered manner so that the communication holes formed in the adjacent plates 151a and 151b do not overlap each other.

  Next, functions and effects of the present embodiment will be described. (1) As a means for forming a mixing ratio according to a predetermined water common rail pressure using a porous body, a material for sintering the size of the through-holes is used. In the porous body 151 formed on the plurality of flat plates 151a and 151b, the communication holes formed between the adjacent plates 151a and 151b overlap each other. In order to avoid this, the layers may be stacked alternately. Thereby, it is possible to form the mixing ratio according to the fluid pressure by the combination of the stacked plates without depending on the material forming the through-holes of the porous body.

(Other embodiments)
In the present embodiment described above, water is used as the fluid mixed with the light oil. However, the fluid is not limited to water, and any fluid may be used as long as it is a functional fluid capable of storing thermal energy.

  In the present embodiment described above, the emulsifying device 50 is described as having the nozzle body 11. However, the fuel and the functional fluid are not limited to the nozzle body 11 and just before the mixed fluid is injected and supplied to the combustion chamber 106. As long as it mixes, you may have an emulsification apparatus in the injection valve or the injector I.

  In the present embodiment described above, the porous body 51 is a substantially cylindrical body, and the high-pressure fuel and high-pressure water are guided to the inner periphery 51a and the outer periphery 51b, respectively. As long as it has the structure which guides, it is not limited to a substantially cylindrical body, but may be any shape such as a substantially spherical body or a substantially conical body.

  In the present embodiment described above, the fuel supplied to drive the engine 100 has been described as light oil, but may be any of fuel such as kerosene and diesel alternative fuel such as dimethyl ether.

  In addition, although it demonstrated by the structure which each uses a high-pressure supply pump and a common rail as each pressurization means of a fuel and a functional fluid, if it is a high-pressure supply pump which can discharge to a predetermined | prescribed high pressure state, a high-pressure supply pump It may be a pressurizing means.

It is a lineblock diagram showing the whole fuel injection device composition of a 1st embodiment of the present invention. It is typical sectional drawing which shows the structure of the injector in FIG. 3A and 3B are views showing a fuel injection nozzle in FIG. 2, in which FIG. 3A is a cross-sectional view, and FIG. 3B is a perspective view showing a porous body in FIG. FIG. 2 is a flowchart showing a control process executed in order to control injection of a mixed fluid of fuel and water in the ECU in FIG. 1. FIG. It is a graph which shows each characteristic of the injection rate with respect to the crank angle, the heat release rate, and the in-cylinder temperature in the fuel injection device of the first embodiment. It is a combustion pattern figure of the diesel engine in the fuel injection device of a 1st embodiment. FIGS. 7A and 7B are diagrams showing a mixing apparatus according to the second embodiment, in which FIG. 7A is a schematic perspective view, and FIG. 7B is a stacked plate made of the porous body in FIG. It is an expanded view which shows adjacent plates among these. It is a graph which shows each characteristic of the injection rate with respect to the crank angle in a prior art fuel injection apparatus, a heat release rate, and the in-cylinder temperature. It is a combustion pattern figure of the diesel engine in the fuel injection apparatus of a prior art.

Explanation of symbols

Pf Diesel oil pump (high pressure supply pump)
Pw water pump (high pressure supply pump)
Rf Light oil common rail (pressure accumulation chamber)
Rw water common rail (accumulation chamber)
I Injector (fuel injection valve)
Bi Electromagnetic valve for injection control N Injection nozzle 11 Nozzle body 12 Guide hole 13 Valve seat 15 Suck part (suck chamber)
16 Fuel reservoir 17 Fuel supply hole 18, 19 Supply piping 31 Needle 36 Abutting portion 41 Injection hole 50 Emulsifying device (mixing means)
51 porous body 51a inner periphery 51b outer periphery

Claims (8)

In a fuel injection device for injecting and supplying a mixed fluid of fuel and functional fluid to a combustion chamber,
Fuel pressurizing means for pressurizing the fuel to a predetermined pressure;
The functional fluid is a fluid capable of storing thermal energy, and a fluid pressurizing unit that pressurizes the functional fluid to a predetermined pressure;
A fuel injection device comprising: mixing means for mixing the high-pressure fuel having the predetermined pressure and the high-pressure functional fluid having the predetermined pressure into a mixed fluid having a predetermined ratio. 2. The fuel injection device according to claim 1, wherein the mixing unit includes a porous body that separates and disperses the high-pressure fuel and the high-pressure functional fluid. 3. The fuel injection device according to claim 2, wherein the porous body has a structure in which the high-pressure fuel is guided to an inside and the high-pressure functional fluid is guided to an outer periphery. The porous body is formed in a plurality of flat plates,
The fuel injection device according to claim 2, wherein the adjacent plates are alternately formed and stacked so that communication holes do not overlap each other. The fuel injection device according to any one of claims 2 to 4, wherein the porous body is made of shirasu porous glass. A needle having a contact portion at the tip;
A guide hole that fits the needle so as to be reciprocally slidable in the axial direction, and a nozzle body that has a valve seat that contacts and separates from the contact portion;
The fuel injection device according to any one of claims 1 to 5, wherein the mixing unit is provided in the nozzle body or the injection valve. A fluid valve for circulating and blocking the high-pressure functional fluid to the mixing means;
Control for adjusting the pressure of the high-pressure fuel, the pressure of the high-pressure functional fluid, and the opening period of the fluid valve;
Control means for performing control to eject and stop the mixed fluid by raising and lowering the needle to separate and seat the contact portion and the valve seat. The fuel injection device according to any one of claims 1 to 6. The functional fluid is water,
The fuel injection device according to any one of claims 1 to 7, wherein the predetermined water pressure is higher than the predetermined fuel pressure.

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