JP2009185609A - Fuel injection device for multiple cylinder internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device for a multiple cylinder internal combustion engine, efficiently boosting different kinds of fuels and supplying them to fuel injection valves. <P>SOLUTION: This fuel injection device 20 includes: the fuel injection valves 25 provided to every cylinders 2 injecting GTL fuel and light fuel oil; a fuel pump 21 pressuring the GTL fuel; pressure boosting mechanisms 26 provided for every cylinders 2, having first pressure chambers 81a introducing the GTL fuel boosted by the fuel pumps 21 and boosting the light fuel oil in time before fuel injection timing comes by using pressure of the GTL fuel introduced into the first pressure chambers 81a; connection passages 90A to 90D connecting the first pressure chambers 81a of the two pressure boosting mechanisms 26 having mutually different light fuel oil boosting timing; and operating valves 91A to 91D opening/closing the connection passages 90A to 90D in conjunction with light fuel oil boosting operation by the pressure boosting mechanisms 26. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel injection device that is applied to a multi-cylinder internal combustion engine in which fuel injection timing is set for each cylinder and configured to be able to inject two types of fuel.

  2. Description of the Related Art There is known a fuel injection device that injects two different types of fuel such as a high cetane number fuel and a low cetane number fuel into a combustion chamber at a ratio corresponding to the operating state of the internal combustion engine. In order to selectively inject such two types of fuel with a common fuel injection valve, it is necessary to increase the pressure of each fuel to a predetermined fuel pressure. Note that Patent Documents 1 to 5 exist as prior art documents related to the present invention.

Japanese Utility Model Publication 2-115596 JP-A-10-220301 JP 2002-206470 A JP 2002-534642 A JP 2003-193913 A

  In order to realize boosting for each fuel as described above, it may be possible to boost each fuel separately by providing a fuel pump for each fuel. However, the more fuel pumps are used, the more energy is consumed to drive them. So efficiency is bad.

  Accordingly, an object of the present invention is to provide a fuel injection device for a multi-cylinder internal combustion engine capable of efficiently boosting different types of different fuels and supplying them to a fuel injection valve.

  The fuel injection device of the present invention is a fuel injection device for a multi-cylinder internal combustion engine that is applied to a multi-cylinder internal combustion engine in which fuel injection timing is set for each cylinder, and is capable of injecting different first fuel and second fuel. A fuel injection valve provided for each cylinder; a fuel pump for boosting one of the first fuel and the second fuel; and the one fuel boosted by the fuel pump A first supply means for supplying fuel to the fuel injection valve; a pressure chamber into which the one fuel boosted by the fuel pump is introduced; and the pressure of the one fuel introduced into the pressure chamber is used. Then, a pressure increasing mechanism provided for each cylinder for boosting the other fuel in accordance with the arrival of the fuel injection timing, and supplying the other fuel boosted by the pressure increasing mechanism to the fuel injection valve Second supply means for performing the other A connecting passage connecting the pressure chambers of the two pressure increasing mechanisms having different pressure increasing timings, and an opening / closing means for opening and closing the connecting passage in conjunction with the pressure increasing operation of the other fuel by the pressure increasing mechanism. By solving, the above-mentioned problem is solved.

  According to this fuel injection device, the pressure of one fuel boosted by the fuel pump can be used to boost the pressure of the other fuel by the pressure increasing mechanism. For this reason, since it is not necessary to provide a fuel pump for each of the first fuel and the second fuel, it is possible to increase the pressure of the first fuel and the second fuel more efficiently than when a fuel pump is provided for each fuel. In addition, the pressure chambers of the two pressure increasing mechanisms having different fuel boosting timings are connected by a connection passage, and the connection passage is opened and closed by the opening / closing means in conjunction with the fuel pressure increasing operation by the pressure increasing mechanism. For this reason, by opening the connection passage with the opening / closing means after the pressure increase by the pressure increase mechanism that the pressure increase timing comes first, the fuel used for the pressure increase is supplied to the pressure increase mechanism that the pressure increase timing comes later. Can lead to a pressure chamber. That is, since the fuel used for boosting can be reused between the pressure boosting mechanisms provided for each cylinder, the discharge flow rate of the fuel pump can be reduced. As a result, the efficiency for boosting the first fuel and the second fuel is improved as compared with the case where such reuse is not performed.

  The combination of the pressure increasing mechanisms in which the pressure chambers are connected by the connection passage may be any combination as long as the pressure increasing timing is different. Since the pressure increase timing by the pressure increase mechanism is set before the arrival of the fuel injection timing, for example, the pressure chambers of two pressure increase mechanisms provided for two cylinders whose fuel injection timing is adjacent to each other are connected to each other You may tie in. In addition, when the fuel injection device of the present invention is applied to an internal combustion engine having three or more cylinders, the pressure chambers of two pressure increasing mechanisms provided for two cylinders whose fuel injection timings are not adjacent to each other are connected to each other. You may connect with a passage.

  There is no particular limitation on the configuration of the fuel injection valve as long as the first fuel and the second fuel can be distinguished and injected. For example, the fuel injection valve is provided with a first valve chamber on the center side and a second valve chamber partitioned by a partition wall with respect to the first valve chamber on the outer peripheral side, and the first valve chamber is provided at the tip. A valve main body provided with a first nozzle hole communicating with the valve chamber and a second nozzle hole communicating with the second valve chamber, and disposed in the first valve chamber so as to be able to open and close the first nozzle hole. A first valve body, a second valve body disposed in the second valve chamber so as to be able to open and close the second nozzle hole, a first drive mechanism for opening and closing the first valve body, and the first A second drive mechanism that opens and closes the second valve body independently of driving the first valve body by a drive mechanism, wherein the first supply means is the first valve chamber or the second valve. The one fuel is supplied to one of the valve chambers, and the second supply means is connected to the other valve chamber of the first valve chamber or the second valve chamber. Fee may be supplied (claim 2). According to this aspect, when the first valve body is driven to open and close by the first drive mechanism of the fuel injection valve, the fuel guided to the first valve chamber is injected from the first injection hole of the valve body, and the second drive is performed. When the second valve body is driven to open and close by the mechanism, the fuel guided to the second valve chamber is injected from the second injection hole of the same valve body. Thereby, two different types of fuel can be injected independently of each other. The injection ratio of the first fuel and the second fuel at one fuel injection timing may be appropriately determined according to the operating state of the internal combustion engine. The injection ratio can be realized by operating the first drive mechanism and the second drive mechanism, respectively.

  In one aspect of the fuel injection device of the present invention, the internal combustion engine may be a diesel engine, the first fuel may be GTL fuel, and the second fuel may be light oil. According to this aspect, if one fuel pump capable of boosting the GTL fuel to a predetermined fuel pressure is prepared, the gas oil can be boosted by the pressure boosting mechanism. be able to.

  As described above, according to the present invention, since the pressure of one fuel boosted by the fuel pump can be used to boost the pressure of the other fuel by the pressure increasing mechanism, the first fuel and the second fuel can be efficiently used. Boosts well. In addition, since the pressure chambers of the two pressure increasing mechanisms having different fuel boosting timings are connected by a connecting passage, the connecting passage is opened and closed by the opening / closing means in conjunction with the fuel pressure increasing operation by the pressure increasing mechanism. The fuel used for boosting can be reused between the boosting mechanisms provided for each cylinder. As a result, the efficiency for boosting the first fuel and the second fuel is improved as compared with the case where such reuse is not performed.

  FIG. 1 shows a form in which a fuel injection device according to the present invention is applied to a diesel engine (hereinafter abbreviated as an engine) as a multi-cylinder internal combustion engine. The engine 1 is mounted on a vehicle as a driving power source, and includes a plurality of (four in the figure) cylinders 2 arranged in a line in the left-right direction in the figure, and an intake passage that guides intake air into the cylinders 2. 3, an exhaust passage 4 through which exhaust from the cylinder 2 is guided, and a turbocharger 5 provided between the intake passage 3 and the exhaust passage 4.

  An air cleaner 6 for filtering the intake air and an air flow meter 7 for detecting the intake air amount are provided upstream of the compressor 5a in the intake passage 3. An intake throttle valve 8 for adjusting the intake air amount is provided on the downstream side of the compressor 5a. On the other hand, at least one exhaust purification catalyst 9 is provided in the exhaust passage 4 on the downstream side of the turbine 5b. An EGR passage 10 is connected to the exhaust manifold 4 a of the exhaust passage 4. A part of the exhaust discharged from the cylinder 2 to the exhaust manifold 4a sequentially passes through the EGR cooler 11 and the EGR valve 12 in the EGR passage 10, and returns between the intake throttle valve 8 in the intake passage 3 and the intake manifold 3a.

  A fuel tank 14 is provided in a vehicle on which the engine 1 is to be mounted. The fuel tank 14 is provided with a first storage chamber 15 for storing GTL (abbreviation of Gas to Liquids) fuel as the first fuel, and a second storage chamber 16 for storing light oil as the second fuel. Each fuel in the fuel tank 14 is injected into the cylinder 2 of the engine 1 by the fuel injection device 20.

  The fuel injection device 20 includes a fuel pump 21 that sucks the GTL fuel in the first storage chamber 15 through the segmenter 17 and pressurizes the fuel, and a low-pressure feed pump 22 that sends out light oil in the second storage chamber 16 through the segmenter 17. A common rail 23 for storing high-pressure GTL fuel fed from the fuel pump 21, a delivery pipe 24 for guiding low-pressure light oil sent from the feed pump 22, and a common rail 23 and a delivery pipe 24 are connected to the common rail 23 and the delivery pipe 24, respectively. A fuel injection valve 25 that injects into the fuel tank 2 and a pressure-increasing mechanism 26 that boosts the light oil introduced through the delivery pipe 24 using the pressure of the GTL fuel that has been boosted by the fuel pump 21. Yes.

  The discharge pressure of the feed pump 22 is lower than the discharge pressure of the fuel pump 21. For example, while the discharge pressure of the fuel pump is about 100 MPa or higher, the discharge pressure of the feed pump 22 is about 0.5 MPa. The fuel injection valve 25 is provided for each cylinder 2. One pressure increasing mechanism 26 is provided for each fuel injection valve 25, that is, for each cylinder 2. Each fuel injection valve 25 has a function of injecting GTL fuel and light oil into the cylinder 2 independently of each other. Between the fuel injection valve 25 and the storage chambers 15 and 16 of the fuel tank 14, return pipes 18 and 19 for returning excess fuel are provided, respectively. In the engine 1, the fuel injection timing by the fuel injection valve 25 is set for each cylinder 2. When cylinder numbers # 1, # 2, # 3, and # 4 are assigned from one left end to the other right end in the direction in which the cylinders 2 of the engine 1 are arranged, the fuel injection timing for these cylinders 2 is # 1, The order is # 3, # 4, and # 2. Hereinafter, when the cylinders 2 need to be distinguished from each other, the above cylinder numbers may be used.

  Next, the details of the fuel injection valve 25 will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view schematically showing the configuration of the fuel injection valve 25. As shown in the figure, the fuel injection valve 25 includes a valve main body 31 that functions as a casing of the entire fuel injection valve 25, and a first needle 32 and a second valve body as first valve bodies built in the valve main body 31. As a second needle 33, a first drive mechanism 34 that drives the first needle 32, and a second drive mechanism 35 that drives the second needle 33.

  The first needle 32 has a solid shaft shape, and the second needle 33 has a hollow cylindrical shape. A first valve chamber 36 is provided on the center side of the distal end portion (lower end portion in FIG. 2) 31a of the valve main body 31, and a second valve chamber 37 is provided on the outer peripheral side. These valve chambers 36 and 37 are partitioned by a partition wall 38 so that fuel cannot flow. The tip 31a of the valve body 31 is formed in a tapered cone shape, and the tip 31a has a first injection hole 39 that communicates with the first valve chamber 36 and a second injection hole 40 that communicates with the second valve chamber 37. Each is provided. The first needle 32 is disposed in the first valve chamber 36 so as to be movable in the direction of the center line CL of the fuel injection valve 25 by fitting the piston flange 32a at the rear end thereof to the inner peripheral surface 38a of the partition wall 38. Has been.

  The second needle 33 is disposed in the second valve chamber 37 so as to be movable in the direction of the center line CL by being fitted to the outer peripheral surface 38 b of the partition wall 38. When the first needle 32 moves to the distal end side of the valve body 31, the first injection hole 39 is closed by the tapered surface 32b at the distal end of the first needle 32, and the first needle 32 is moved to the rear end side (see FIG. 2, the first nozzle hole 39 is opened. On the other hand, when the second needle 33 moves to the distal end side of the valve body 31, the second injection hole 40 is closed by the tapered surface 33 b at the distal end of the second needle 33, and the second needle 33 is moved to the rear end side of the valve body 31. When it moves to (the upper end side in FIG. 2), the second nozzle hole 40 opens.

  The first drive mechanism 34 is slidably fitted to a first needle return spring 42 that presses the first needle 32 toward the tip 31 a of the valve body 31 and a first cylinder 43 of the valve body 31. A piston 44, a first outer valve 46 disposed in the first solenoid chamber 45 of the valve body 31, a first outer valve return spring 47 that presses the first outer valve 46 toward the first cylinder 43, and a first outer valve return thereof And a first solenoid coil 48 disposed on the outer periphery of the spring 47.

  The interior of the first cylinder 43 is divided into a first spring chamber 43a on the front end side and a first command chamber 43b on the rear end side by the first command piston 44. A small-diameter needle holding shaft 44 a is provided on the distal end side of the first command piston 44. The needle holding shaft 44 a can come into contact with the rear end of the first needle 32 when the first needle 32 closes the first injection hole 39. A first high pressure fuel passage 50 is connected to the first command chamber 43 b via a first orifice 51. The first high-pressure fuel passage 50 is formed in the valve main body 31, and a part thereof communicates with the first valve chamber 36. The first command chamber 43 b communicates with the first solenoid chamber 45 through the second orifice 52. The inner diameter of the second orifice 52 is set smaller than the inner diameter of the first orifice 51. Further, each of the first spring chamber 43 a and the first solenoid chamber 45 is connected to a first low-pressure fuel passage 53 formed in the valve body 31.

  The first outer valve 46 is made of a magnetic material. When the first solenoid coil 48 is in a non-excited state, the first outer valve 46 is held at a position where the second orifice 52 is closed by the spring force of the first outer valve return spring 47. In this case, the space between the first command chamber 43b and the first low-pressure fuel passage 53 is closed. On the other hand, when the first solenoid coil 48 is excited, the first outer valve 46 is opened, whereby the first command chamber 43 b is connected to the first low-pressure fuel passage 53 via the second orifice 52 and the first solenoid chamber 45. Is done.

  The second drive mechanism 35 includes a second needle return spring 62 that presses the second needle 33 toward the tip 31 a of the valve body 31 and a second command that is slidably fitted to the second cylinder 63 of the valve body 31. Piston 64, second outer valve 66 disposed in second solenoid chamber 65 of valve body 31, second outer valve return spring 67 that presses second outer valve 66 against second cylinder 63, and second outer valve return spring And a second solenoid coil 68 disposed on the outer periphery of 67.

  The inside of the second cylinder 63 is divided into a second spring chamber 63a on the front end side and a second command chamber 63b on the rear end side by the second command piston 64. A hollow needle holding shaft 64 a is provided on the distal end side of the second command piston 64. The needle holding shaft 64 a can come into contact with the rear end of the second needle 33 when the second needle 33 closes the second injection hole 40. A second high pressure fuel passage 70 is connected to the second command chamber 63 b via a first orifice 71. The second high-pressure fuel passage 70 is formed in the valve body 31, and a part of the second high-pressure fuel passage 70 communicates with the second valve chamber 37. The second command chamber 63 b communicates with the second solenoid chamber 65 through the second orifice 72. The inner diameter of the second orifice 62 is set smaller than the inner diameter of the first orifice 61. Further, each of the second spring chamber 63 a and the second solenoid chamber 65 is connected to a second low-pressure fuel passage 73 formed in the valve body 31.

  The second outer valve 66 is made of a magnetic material. When the second solenoid coil 68 is in a non-excited state, the second outer valve 66 is held at a position where the second orifice 72 is closed by the spring force of the second outer valve return spring 67. In this case, the space between the second command chamber 63b and the second low pressure fuel passage 73 is closed. On the other hand, when the second solenoid coil 68 is excited, the second outer valve 66 is opened, so that the second command chamber 63b is connected to the second low-pressure fuel passage 73 via the second orifice 72 and the second solenoid chamber 65. Is done.

  In the fuel injection valve 25 having the above configuration, high-pressure GTL fuel stored in the common rail 23 is supplied to the first high-pressure fuel passage 50, and the pressure is increased by the pressure-increasing mechanism 26 to the second high-pressure fuel passage 70. Gas oil is supplied. As a result, high-pressure GTL fuel is introduced into the first valve chamber 36 and the first command chamber 43b of the fuel injection valve 25, and high-pressure light oil is introduced into the second valve chamber 37 and the second command chamber 63b. The first low-pressure fuel passage 53 is connected to the first return pipe 18, and the second low-pressure fuel passage 73 is connected to the second return pipe 19.

  As shown in FIG. 2, when the solenoid coils 48 and 68 are respectively de-energized, the second orifices 52 and 72 are closed by the outer valves 46 and 66, respectively, so that the fuel pressure is applied to the command chambers 43b and 63b. Be trapped. As a result, the command pistons 44 and 64 are pushed out toward the distal end side of the fuel injection valve 25, and the needle holding shafts 44a and 64a push the needles 32 and 33 along with them, and the nozzle holes 39 and 40 are closed. In these states, no fuel is injected.

  On the other hand, when the solenoid coils 48 and 68 are energized, the outer valves 46 and 66 are attracted to the solenoid coils 48 and 68 as shown in FIG. 3, and the second orifices 52 and 72 are opened to open the command chambers 43b and 63b. The fuel flows out into the low pressure fuel passages 53 and 73, respectively. As a result, the pressure in the command chambers 43b and 63b decreases, and the force for pressing the needles 32 and 33 against the distal end side of the fuel injection valve 25 decreases. As a result, the needles 32 and 33 are pushed into the rear end portion of the fuel injection valve 25 by the pressure of the fuel acting on the piston flanges 32a and 33a, and the injection holes 39 and 40 are opened. As a result, GTL fuel is injected from the first injection hole 39 and light oil is injected from the second injection hole 40. The amount of fuel injected from the nozzle holes 39 and 40 can be appropriately adjusted by changing the length of time for supplying the exciting current to the solenoid coils 48 and 68 (on-duty ratio in the case of PWM control). In addition, by changing the supply of exciting currents to the first solenoid coil 48 and the second solenoid coil 68 independently of each other, the timing of fuel injection from each of the nozzle holes 39 and 40 can be set independently. Further, the ratio of the fuel injection amount (hereinafter referred to as the injection ratio) can be changed.

  Next, the details of the pressure increasing mechanism 26 will be described with reference to FIG. FIG. 4 schematically shows the configuration of the pressure-increasing mechanism 26, the mutual connection relationship of the pressure-increasing mechanisms 26 provided for each cylinder 2, and other configurations such as these pressure-increasing mechanisms 26 and the fuel injection valves 25. The connection relation of is schematically shown. The pressure increasing mechanism 26 increases the pressure of the light oil sent from the feed pump 22 by using the pressure of the GTL fuel supplied from the common rail 23.

  In order to realize this boosting function, the pressure increasing mechanism 26 includes a pressure increasing cylinder 81, a pressure increasing piston 82 slidably accommodated in the pressure increasing cylinder 81, and an electromagnetic for switching between supply and stop of GTL fuel. And a drive type control valve 83. The pressure-increasing piston 82 has a piston part 82a and a pressurizing plunger 82b arranged coaxially at one end of the piston part 82a. The pressure increasing cylinder 81 is divided into a first pressure chamber 81 a and a second pressure chamber 81 b by a piston portion 82 a of the pressure increasing piston 82. Further, a pressure increasing chamber 81c is connected to the second pressure chamber 81b, and a pressure plunger 82b is fitted into the pressure increasing chamber 81c. The inner diameter of the pressure increasing chamber 81c is sufficiently smaller than that of the first pressure chamber 81a. Therefore, the area of the pressure plunger 82b is sufficiently small as compared with the area of the piston portion 82a of the pressure increasing piston 82. The pressure increasing chamber 81c is provided with a return spring 89 that urges the pressure increasing piston 82 in the direction in which the volume increases.

  The pressure-increasing mechanism 26 includes a first high-pressure fuel passage 85 for connecting the common rail 23 and the first pressure chamber 81a to guide high-pressure GTL fuel to the first pressure chamber 81a, a delivery pipe 24, and a pressure-increasing chamber 81c. And a low pressure fuel passage 86 for guiding low pressure light oil to the pressure increasing chamber 81c. The first high-pressure fuel passage 85 is branched halfway, and the branch passage 85 a communicates with the first high-pressure fuel passage 50 of the fuel injection valve 25. That is, since the GTL fuel boosted by the fuel pump 21 is supplied to the fuel injection valve 25 through the common rail 23 and the first high pressure fuel passage 85, the first supply according to the present invention is performed by the common rail 23 and the first high pressure fuel passage 85. Means are configured. The low-pressure light oil guided in the low-pressure fuel passage 86 is guided to the pressure increasing chamber 81 c through the check valve 87. The check valve 87 is provided in a direction that can prevent the backflow of light oil from the pressure increasing chamber 81 c to the low pressure fuel passage 86. A second high pressure fuel passage 88 is connected to the pressure increasing chamber 81 c, and the second high pressure fuel passage 88 communicates with the second high pressure fuel passage 70 of the fuel injection valve 25. That is, since the light oil boosted by the pressure increasing mechanism 26 is supplied to the fuel injection valve 25 through the second high pressure fuel passage 88, the second supply means according to the present invention is configured by the second high pressure fuel passage 88. .

  With such a configuration, when the high pressure GTL fuel is guided to the first pressure chamber 81 a and the pressure in the first pressure chamber 81 a of each pressure increasing mechanism 26 increases, the pressure increasing piston 82 overcomes the spring force of the return spring 89. Pushed down. The pressurizing plunger 82b reduces the volume of the pressure increasing chamber 81c by pushing down the pressure increasing piston 82. Since the pressure increasing chamber 81c is filled with low pressure light oil, the light oil in the pressure increasing chamber 81c is guided to the second high pressure passage 70 of the fuel injection valve 25 while being pressurized by the pressure plunger 82b. A part of the GTL fuel used for boosting the light oil leaks into the second pressure chamber 81 b, and the leaked GTL fuel is returned to the return pipe 18 through the leak passage 95. Further, the light oil leaked by the pressurization of the plunger 82 b is returned to the return pipe 19 through the leak passage 96.

  In the fuel injection device 20 of the present embodiment, the high pressure GTL fuel used for boosting the light oil is reused by the other pressure boosting mechanisms 26, and therefore the first pressure chambers 81a of the two pressure boosting mechanisms 26 adjacent to each other in pressure boosting timing. Are connected by connection passages 90A to 90D. The pressurization timing of the light oil is set so as to meet before the arrival of the fuel injection timing for each cylinder 2. That is, light oil is boosted in the order of # 1, # 3, # 4, # 2, # 1,. Accordingly, the connecting passage 90A connects the first pressure chamber 81a of the pressure increasing mechanism 26 provided in the # 1 cylinder 2 and the first pressure chamber 81a of the pressure increasing mechanism 26 provided in the # 2 cylinder 2. The connection passage 90B connects the first pressure chamber 81a of the pressure increasing mechanism 26 provided in the # 3 cylinder 2 and the first pressure chamber 81a of the pressure increasing mechanism 26 provided in the # 2 cylinder 2; The connection passage 90C connects the first pressure chamber 81a of the pressure-increasing mechanism 26 provided in the # 4 cylinder 2 and the first pressure chamber 81a of the pressure-increasing mechanism 26 provided in the # 2 cylinder 2. The passage 90D connects the first pressure chamber 81a of the pressure-increasing mechanism 26 provided in the # 2 cylinder 2 and the first pressure chamber 81a of the pressure-increasing mechanism 26 provided in the # 2 cylinder 2. The connection passages 90A to 90D are provided with electromagnetically driven on / off valves 91A to 91D as opening / closing means.

  The pressure increase of the light oil is realized by operating the control valve 83 of each pressure increasing mechanism 26 and each of the on-off valves 91A to 91D in conjunction with each other. For example, before the fuel injection timing of the # 1 cylinder 2 arrives, the on-off valve 91D is opened to guide the used GTL fuel to the first pressure chamber 81a of the pressure increasing mechanism 26 provided in the # 1 cylinder 2. The on-off valve 91D is closed. With the connection passage 90D closed by the on-off valve 91D, the control valve 83 of the pressure increasing mechanism 26 provided in the cylinder # 1 is opened, and the high pressure GTL fuel stored in the common rail 23 is supplied to the first pressure. It leads to the chamber 81a and pressurizes light oil. When the pressure increase ends, this time, the on-off valve 91A is opened, the used GTL fuel is guided to the first pressure chamber 81a of the pressure-increasing mechanism 26 provided in the # 2 cylinder 2, and then the on-off valve 91A is closed. Thereafter, similarly, the control valve 83 of the pressure increasing mechanism 26 provided in the cylinder # 3 is opened with the connection passage 90A closed by the on-off valve 91A, and the high-pressure GTL fuel stored in the common rail 23 is supplied. The pressure of the light oil is increased by guiding it to the first pressure chamber 81a. When the pressure increase is completed, the on-off valve 91B is opened, the used GTL fuel is guided to the first pressure chamber 81a of the pressure-increasing mechanism 26 provided in the # 4 cylinder, and then the on-off valve 91B is closed. ... In this way, by sequentially operating the on-off valves 91A to 91D in conjunction with the pressure increasing operation of the pressure increasing mechanism 26, the GTL fuel used for pressure increasing between the pressure increasing mechanisms 26 is reused. can do.

  The fuel injection device 20 having the above configuration is controlled by an engine control unit (ECU) 100 shown in FIG. The ECU 100 is configured as a computer unit for controlling the operating state of the engine 1. The ECU 100 outputs a signal corresponding to the intake air amount output from the air flow meter 7, a signal corresponding to the crank angle output from the crank angle sensor 101 and the engine speed (rotation speed), and an accelerator opening sensor 102. Various calculations are executed with reference to a signal corresponding to the opening of the accelerator pedal, and the engine 1 is operated by operating control target devices such as the intake throttle valve 8, the EGR valve 12, and the fuel injection valve 25 according to the calculation results. Control the operating state to the target state.

  In order to control the fuel injection operation of the fuel injection valve 25, a first coil drive circuit 103 and a second coil drive circuit 104 are connected to the ECU 100. Although only one set of coil drive circuits 103 and 104 is shown in FIG. 1, one set of coil drive circuits 103 and 104 is provided for each fuel injection valve 25. The first coil drive circuit 103 switches supply and stop of excitation current from a power source (not shown) to the first solenoid coil 48 of the fuel injection valve 25 in accordance with an instruction from the ECU 100. The second coil drive circuit 104 In accordance with the instruction from, the supply of the excitation current to the second solenoid coil 68 of the fuel injection valve 25 from the power source and the supply stop are switched. Thus, when the first needle 32 is driven to open and close by the first drive mechanism 34 of the fuel injection valve 25, the GTL fuel guided to the first valve chamber 36 is injected from the first injection hole 39 of the valve body 31, When the second needle 33 is driven to open and close by the second drive mechanism 35, the light oil guided to the second valve chamber 37 is injected from the second injection hole 40 of the same valve body 31. Thereby, two different types of fuel can be injected independently of each other. The injection ratio of the first fuel and the second fuel at one fuel injection timing may be appropriately determined according to the operating state of the engine 1. For example, the injection ratio of light oil can be maximized in the high load and low rotation region of the engine 1, and the GTL fuel injection ratio can be controlled to increase as the distance from the region increases.

  Further, in order to control the pressure increasing operation by the pressure increasing mechanism 26, the ECU 100 refers to the output signal of the crank angle sensor 101 and boosts the light oil in the order described above before the fuel injection timing for each cylinder 2 arrives. Thus, each control valve 83 and each on-off valve 91A-91D are each operated. As a result, the discharge flow rate of the fuel pump 21 that pressurizes the GTL fuel can be reduced as compared with the case where such reuse is not performed, so that the efficiency for boosting the GTL fuel and the light oil is improved.

  The present invention is not limited to the above-described form and can be carried out in an appropriate form. The present invention is not limited to an example using GTL fuel and light oil, and can be applied to an appropriate fuel injection device as long as two types of fuel are used. The type of the internal combustion engine is not limited to a diesel engine, and can be applied to, for example, an in-cylinder direct injection type spark ignition engine that uses two types of fuel.

  In the embodiment described above, the first pressure chambers 81a of the pressure increasing mechanism 26 provided for the two cylinders 2 adjacent to each other in the fuel injection timing are connected by the connection passages 90A to 90D, but the pressure increasing timing is different. If there is enough. For example, when the fuel injection device of the present invention is applied to an internal combustion engine having three or more cylinders, the pressure chambers of two pressure increasing mechanisms provided for two cylinders whose fuel injection timings are not adjacent to each other are connected to each other. You may connect with a passage. Even in this case, the fuel used for boosting one fuel between the pressure increasing mechanisms can be reused for boosting the other fuel. The on-off valves 91 </ b> A to 91 </ b> D in the above-described form are only examples of on-off means. Accordingly, the connection passage is opened and closed in conjunction with the pressure increasing operation of the pressure increasing mechanism so that the fuel pressurized by the fuel pump can be prevented from being simultaneously introduced into the pressure chambers of the two pressure increasing mechanisms through the connection passage. The opening / closing means may be realized with any configuration.

  The pressure increasing mechanism and the fuel injection valve may be integrated or separate. For example, the pressure increasing mechanism 26 can be incorporated in the valve main body 31 of the fuel injection valve 25 shown in FIGS.

The figure which shows the internal combustion engine to which the fuel-injection apparatus which concerns on one form of this invention was applied. The cross-sectional schematic diagram in the valve closing state of a fuel injection valve. The cross-sectional schematic diagram in the valve opening state of a fuel injection valve. The figure which showed typically the structure of a pressure increase mechanism, and the connection relation of the pressure increase mechanism, and the connection relation of the pressure increase mechanism and other structures, such as a fuel injection valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multi-cylinder internal combustion engine 2 Cylinder 20 Fuel-injection apparatus 21 Fuel pump 23 Common rail (1st supply means)
25 Fuel injection valve 26 Pressure increasing mechanism 31 Valve body 32 First needle (first valve body)
33 Second needle (second valve body)
34 1st drive mechanism 35 2nd drive mechanism 36 1st valve chamber 37 2nd valve chamber 38 Partition 39 1st injection hole 40 2nd injection hole 81a 1st pressure chamber (pressure chamber)
90A-90D Connection passages 91A-91D Open / close valve (open / close means)

Claims (3)

In a fuel injection device for a multi-cylinder internal combustion engine applied to a multi-cylinder internal combustion engine in which fuel injection timing is set for each cylinder,
A fuel injection valve provided for each of the cylinders capable of injecting different first fuel and second fuel, a fuel pump for boosting one of the first fuel and the second fuel, First supply means for supplying the one fuel boosted by the fuel pump to the fuel injection valve; a pressure chamber into which the one fuel boosted by the fuel pump is introduced; and A pressure-increasing mechanism provided for each cylinder for boosting the other fuel in accordance with the pressure of the one fuel introduced into the pressure chamber before the fuel injection timing arrives; and the pressure-increasing mechanism A second supply means for supplying the other fuel whose pressure has been increased to the fuel injection valve; a connecting passage connecting the pressure chambers of the two pressure-increasing mechanisms having different pressure increasing timings of the other fuel; Boosting the other fuel by the pressure boosting mechanism The fuel injection system for a multi-cylinder internal combustion engine, characterized in that it comprises a closing means for opening and closing the connecting passage in conjunction with the work, the. The fuel injection valve is provided with a first valve chamber on the center side and a second valve chamber partitioned by a partition wall with respect to the first valve chamber on the outer peripheral side, and the first valve chamber is provided at a tip portion. A valve body provided with a first nozzle hole communicating with the second valve hole and a second nozzle hole communicating with the second valve chamber; and a first valve chamber disposed in the first valve chamber so as to be able to open and close the first nozzle hole. A valve body; a second valve body disposed in the second valve chamber so as to be able to open and close the second nozzle hole; a first drive mechanism that opens and closes the first valve body; and the first drive mechanism. A second drive mechanism for opening and closing the second valve body independently of the driving of the first valve body by
The first supply means supplies the one fuel to one of the first valve chamber and the second valve chamber, and the second supply means uses either the first valve chamber or the second valve chamber. The fuel injection device according to claim 1, wherein the other fuel is supplied to the other valve chamber.   The fuel injection device according to claim 1 or 2, wherein the internal combustion engine is a diesel engine, the first fuel is GTL fuel, and the second fuel is light oil.

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