JP6194722B2 - Engine fuel injector - Google Patents

Description

  The present invention reduces resonance noise caused by fuel injection from each injector in an engine fuel injection device, particularly a fuel injection device in which an injector for each cylinder is coupled to a downstream high-pressure fuel pipe branched from a common fuel supply passage. Regarding technology.

  In order to reduce vibration of each injector due to vibration input from the engine body, there is a cylinder provided with a washer-like mass between each injector and the corresponding downstream high-pressure fuel pipe (see Patent Document 1).

JP 2002-54534 A

  By the way, in the case of providing a washer-like mass between the injector and the corresponding downstream high-pressure fuel pipe as in the technique of Patent Document 1, it is necessary to review the specifications of the downstream high-pressure fuel pipe. It is necessary to review and redesign the shape of the high-pressure fuel pipe on the downstream side by the amount of space to which the washer-like mass is added, resulting in an extra cost increase.

  Accordingly, an object of the present invention is to provide an apparatus that can reduce resonance caused by fuel injection from each injector without changing the specifications of the downstream high-pressure fuel pipe.

The fuel injection system of an engine of the present invention, an injector for each cylinder is coupled to the downstream high pressure fuel pipe branched from a common fuel supply passage, an injector for each of the cylinders in fuel injection system of an engine mounted on the cylinder head Oh Ru. In one aspect of the present invention, the mass was attached to each straight portion of the downstream high pressure fuel tube coupled to Lee Njekuta, the mass of the mass thereof, from the injector and the downstream high-pressure fuel pipe which is coupled to the injector It is set so that the resonance frequency of the vibration system becomes lower and the resonance frequencies of the plurality of vibration systems are not the same .

  According to the present invention, the resonance with respect to the vibration input from the engine main body to each injector can be reduced only by retrofitting a mass for each straight portion of the downstream high-pressure fuel pipe whose specification has already been determined. That is, even a vehicle equipped with an engine having a fuel injection device of any specification can be handled without changing the specifications of the parts constituting the fuel injection device. As a result, the vehicle types to which the present invention can be applied can be expanded.

1 is a schematic perspective view of an engine according to a first embodiment of the present invention. 2 is a schematic perspective view of a common rail fuel injection device of Comparative Example 1. FIG. 6 is a schematic perspective view of a common rail fuel injection device of Comparative Example 2. FIG. It is a top view of the mass thing of a 1st embodiment. It is a front view of the mass thing of a 1st embodiment. It is a disassembled perspective view of the mass of 1st Embodiment. It is a front view which shows the initial state of the mass object before attaching. It is the schematic of the site | part which connects each four injectors and a common rail via a downstream high pressure fuel pipe. It is the schematic which shows the connection part of the 1st cylinder injector and the downstream high pressure fuel pipe couple | bonded with this injector. FIG. 6 is a characteristic diagram of vibration acceleration with respect to frequency when a mass is attached to each linear portion of a downstream high-pressure fuel pipe for a common rail fuel injection device provided in a specific engine. It is the schematic of the site | part which connects each four injectors and a common rail via a downstream high pressure fuel pipe | tube for showing mounting | wearing of the mass in the case of a specific engine.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic perspective view of a diesel engine (hereinafter simply referred to as “engine”) 1 according to a first embodiment of the present invention. FIG. 8 is a diagram illustrating four injectors 9A to 9D and a common rail 6 connected to each downstream high-pressure fuel pipe. It is the schematic of the site | part connected via 7A-7D. FIG. 1 mainly shows a cylinder head 2 of an in-line four-cylinder engine.

  The cylinder head 2 of the engine 1 includes a common rail fuel injection device 3 (fuel injection device). The common rail fuel injection device 3 includes a supply pump 4, one upstream high-pressure fuel pipe 5, one common rail 6, four downstream high-pressure fuel pipes 7A, 7B, 7C, and 7D, and four injectors. 9A, 9B, 9C, and 9D are mainly configured. Here, it is assumed that the injector 9A is for the first cylinder, the injector 9B is for the second cylinder, the injector 9C is for the third cylinder, and the injector 9D is for the fourth cylinder.

  A supply pump (not shown) and a common rail 6 which is a fuel supply passage common to each cylinder are connected via an upstream high-pressure fuel pipe 5. The injectors 9A to 9D for each cylinder are connected to the ends of the four downstream high-pressure fuel pipes 7A to 7D that are branched from the common rail 6 and connected to the cylinder head 2 in a row. Is attached.

  In FIG. 1, since the cylinder head 2 is covered with the engine cover 60, the shapes of the injectors 9A to 9D are not shown, but in detail, the injectors 9A to 9D are provided directly facing the combustion chambers of the respective cylinders. . As will be described later with reference to FIG. 9, for example, the entire injector 9A is formed in a rod shape, and a fuel inlet is formed on the side of the injector 9A (left side in FIG. 9). The fuel inlet of this injector 9A is covered with a metal straight tubular pipe 11A. A flare nut 12A is provided at the tip of the straight tubular pipe 11A. The flare nut 12A connects the downstream high-pressure fuel pipe 7A and the straight pipe 11A. At the lower end of the injector 9A, there is provided a nozzle for injecting fuel when the needle valve is lifted from the valve seat and stopping fuel injection when the needle valve is seated on the valve seat. Although not shown, each of the four injectors 9A to 9D configured as described above has a cylinder head that is clamped by a fork part of a fork whose end is fastened to the cylinder head 2 with a bolt. 2 is supported.

Returning to FIG. 1, the upper ends of the injectors 9 </ b> A to 9 </ b> D can be seen from between the engine covers 60. Further, the flare nuts 12 </ b> A to 12 </ b> D are visible from between the engine covers 60.
The positions where the four downstream high-pressure fuel pipes 7A to 7D are attached to the common rail 6 are not attached in this order, but are attached to the common rail 6 in the order of 7A, 7C, 7B, and 7D as shown in FIG. For this reason, the downstream high-pressure fuel pipe 7B coupled to the second cylinder injector 9B and the downstream high-pressure fuel pipe 7C coupled to the third cylinder injector 9C intersect.

  The vibration of the injector 9A due to the vibration input from the engine body is transmitted from the injector 9A to the downstream high-pressure fuel pipe 7A coupled to the injector 9A, and is amplified by the resonance of the vibration system composed of the injector 9A and the downstream high-pressure fuel pipe 7A. To the common rail 6. The resonance of the vibration system composed of the injector 9A and the downstream high-pressure fuel pipe 7A causes the resonance of the vibration system composed of the injectors 9B, 9C, 9D and the downstream high-pressure fuel pipes 7B, 7C, 7D of the other cylinders. .

  Resonance frequencies of the vibration system including the downstream high-pressure fuel pipes 7A to 7D coupled to the injectors 9A to 9D are basically different for each cylinder. For this reason, the four-cylinder system has four vibration systems having different resonance frequencies. The resonance of one vibration system affects the other vibration system. Hereinafter, when distinguishing the four vibration systems, a vibration system including the first cylinder injector 9A and the downstream high-pressure fuel pipe 7A coupled to the injector 9A is referred to as a “first cylinder injector vibration system”. Similarly, a vibration system including the second cylinder injector 9B and the downstream high-pressure fuel pipe 7B coupled to the injector 9B is referred to as a “second cylinder injector vibration system”. Also, a vibration system composed of a third cylinder injector 9C and a downstream high-pressure fuel pipe 7C coupled to the injector 9C is coupled to a "third cylinder injector vibration system", a fourth cylinder injector 9D and the injector 9D. The vibration system composed of the downstream high-pressure fuel pipe 7D is referred to as “vibration system of the fourth cylinder injector”.

  The reason why it is necessary to reduce the resonance of each of the four vibration systems is the limit vibration acceleration that can guarantee the functions of the injectors 9A to 9D (this limit vibration acceleration is hereinafter simply referred to as “limit vibration acceleration”). This is because it is determined in advance.

  There are Comparative Examples 1 and 2 for the first embodiment in which vibrations caused by resonance by these four vibration systems are reduced. This will be described. FIGS. 2 and 3 are schematic perspective views of the common rail fuel injection device 3 of Comparative Examples 1 and 2. FIG. First, in the comparative example 1 shown in FIG. 2, each washer-type mass body 62A, between the mounting nuts 61A to 61D of the downstream high-pressure fuel pipes 7A to 7D and the fuel inlets of the injectors 9A to 9D, 62B, 62C, and 62D are sandwiched and tightened by the mounting nuts 61A to 61D. The addition of the washer-like mass bodies 62A to 62D reduces the vibration acceleration peak at the resonance frequency for each of the four vibration systems, thereby reducing injector vibration.

  However, in Comparative Example 1, all the four downstream high-pressure fuel pipes 7A to 7D connected to the injectors 9A to 9D must be replaced with new parts in accordance with the addition of the mass bodies 62A to 62D. Since the specifications of the four downstream high-pressure fuel pipes 7A to 7D are all changed with the addition of the mass bodies 62A to 62D, the cost increases accordingly.

  Further, due to the change of the resonance frequency of each vibration system, when the masses of the mass bodies 62A to 62D are made different, the shapes (thicknesses, diameters) and the like of the mass bodies 62A to 62D are different in the four vibration systems. come. When the mass bodies 62A to 62D having different shapes and the like in the four vibration systems are assembled at the factory, there is a possibility that they will be mistakenly assembled. Further, when the washer-like mass bodies 62A to 62D are provided between the injectors 9A to 9D and the downstream high-pressure fuel pipes 7A to 7D, the washer-like mass body 62A is assembled before the injector and the downstream high-pressure fuel pipe are assembled. It is necessary to provide a process for assembling ~ 62D.

  On the other hand, in the comparative example 2 shown in FIG. 3, two adjacent high-pressure fuel pipes 7A and 7B and 7C and 7D are connected by stays 64A and 64B. Specifically, two stays 64A and 64B are provided for every two cylinders for four cylinders. The mass bodies 65A and 65B are fixed to the respective stays 64A and 64B. By changing the fixing positions of the mass bodies 65A and 65B, the effective masses of the four vibration systems are changed to change the resonance frequencies of the vibration systems. Are different. That is, the closer the center of gravity of each mass body 65A, 65B is, the more the downstream high-pressure fuel pipes 7B, 7D closer to the center of gravity are compared with the downstream high-pressure fuel pipes 7A, 7C farther from the center of gravity. Therefore, the effective mass can be made different for each vibration system by changing the position of the center of gravity of each mass body 65A, 65B.

  In other words, the comparative example 2 connects the vibration system having a relatively small resonance and the vibration system having a relatively large resonance by the stays 64A and 64B to which the mass bodies 65A and 65B are fixed. It is intended to reduce resonance.

  However, Comparative Example 2 also has a problem. For example, when the resonance of the vibration system of the fourth cylinder injector 9D is relatively small and the resonance of the vibration system of the remaining three vibration systems is relatively large, the vibration system of the fourth cylinder injector 9D and the remaining three vibrations The system must be connected by a single stay with a fixed mass. However, it is impossible to suppress all the resonances of the remaining three vibration systems having a relatively small resonance with one vibration system having a relatively small resonance. Alternatively, if there is no vibration system with relatively small resonance or no resonance in the first place, it is meaningless to connect vibration systems with relatively large resonance with a stay to which a mass body is fixed.

  Therefore, in the first embodiment of the present invention, the mass 21 is independently attached to the straight portions of the respective downstream high-pressure fuel pipes 7A to 7D. 4 is a plan view of the mass 21, FIG. 5 is a front view of the mass 21, FIG. 6 is an exploded perspective view of the mass 21, and FIG. 7 is a straight portion of the downstream high-pressure fuel pipe. It is a front view which shows the initial state of this mass thing 21 before attaching to.

  The mass 21 is composed of the lower member 31 and the upper member 41 as shown in FIG. 6, and sandwiches the straight portions of the downstream high-pressure fuel pipes 7 </ b> A to 7 </ b> D between the lower member 31 and the upper member 41. It is. First, the lower member 31 includes a U-shaped portion 32, a lower matching portion 33, and a support portion 34, and is formed by bending a plate-shaped metal member. That is, as shown in FIG. 7, the lower mating portion 33 extends to the right and the support portion 34 extends upward from the U-shaped portion 32. In the U-shaped portion 32, a lower rubber member 35 that protrudes on both sides of the U-shaped portion 32 (both sides in the vertical direction in FIG. 4) is accommodated to the middle, and the lower rubber member 35 is stored in the U-shaped portion 32. It is fixed with an adhesive. A recess 35b is provided on the upper surface 35a of the lower rubber member 35 in a direction orthogonal to the longitudinal direction of the lower member 31 (left and right direction in FIG. 7).

  As shown in FIG. 6, a round hole 33 a through which the bolt 51 passes is formed in the center of the lower joining portion 33, and screwed with the bolt 51 that has been inserted into the lower surface 33 b of the lower joining portion 33. A nut 36 is fixed by welding. Although it is not always necessary to fix the nut 36 by welding, it is easier for the mass 36 to be attached when the nut 36 is fixed. Further, as shown in FIG. 6, the support portion 34 is provided with a slit 34a that is long in the horizontal direction.

  On the other hand, the upper member 41 includes an upper mating portion 42 and an extending portion 43, and is formed by bending a plate-shaped metal member. That is, the extending portion 43 is provided at a predetermined angle above the upper mating portion 42 as shown in FIG.

  The extending portion 43 is narrow so that it can be inserted into the slit 34a of the lower member 31, and when the extending portion 43 is inserted into the slit 34a of the lower member 31, the extending portion 43 moves slightly in the slit 34a. The vertical width of the slit 34a is made larger than the thickness of the extended portion 43 so as to obtain. After the extended portion 43 is inserted into the slit 34 a of the lower member 31, the extended portion 43 is provided with a grommet 44 so that the extended portion 43 does not come out of the slit 34 a by the grommet 44. ing. Here, the slit 34a, the extending portion 43, and the grommet 44 constitute a mechanism that connects the lower member 31 and one end (the left end in FIG. 7) of the upper member 41 so as to move relative to each other.

  Further, on the lower surface 42b of the upper mating portion 42, as shown in FIG. 7, the upper rubber protrudes on both sides (both sides in the vertical direction in FIG. 4) of the upper mating portion 42 at a position facing the lower rubber member 35. The member 45 is fixed with an adhesive. The lower surface 45a of the upper rubber member 45 is provided with a recess 45b at a position corresponding to the recess 35b. The recess 45b is also provided in a direction orthogonal to the longitudinal direction of the lower member 31 (the left-right direction in FIG. 7).

  An elongated hole 42 a is formed in the upper mating portion 42 at a position facing the round hole 33 a of the lower mating portion 33. This long hole 42a overlaps with the round hole 33a when the two upper and lower mating portions 33, 42 are brought into contact with each other, and further extends toward the opposite side of the extending portion 43 as shown in FIG. . This is to facilitate insertion of the bolt 51 as shown in FIG. 7 in a state (initial state) before the mass 21 is attached to the straight portion of the downstream high-pressure fuel pipe.

  Here, an operation procedure for attaching the mass 21 to the straight portion of the downstream high-pressure fuel pipe will be described. First, in the initial state of the mass 21, as shown in FIG. 7, the upper mating portion 42 is the lower mating portion 33 with the connecting portion between the extending portion 43 and the slit 34 a inserted through the extending portion 43 as a fulcrum. With a predetermined angle. When attaching the mass 21 to the straight portion of the downstream high-pressure fuel pipe, the straight portion of the downstream high-pressure fuel pipe is sandwiched between the depressions 45a and 35a of the upper and lower rubber members 35 and 45 in this initial state, and from above. As shown in FIG. 7, the bolt 51 is inserted into the long hole 42a and the round hole 33a. At this time, by making the width of the elongated hole 42a larger than the width of the round hole 33a, the bolt 51 can be easily inserted even in the initial state of the mass 21 and workability can be improved.

  Next, with the connecting portion between the extended portion 43 and the slit 34a inserted through the extended portion 43 as a fulcrum, the upper aligning portion 42 is rotated toward the lower aligning portion 33 and brought into contact therewith, FIG. The right end of the lower surface 45a of the upper rubber 45 abuts on the corner of the lower mating portion 33 and the U-shaped portion 32. When the upper mating portion 42 is further rotated toward the lower mating portion 33, the entire upper rubber member 45 is compressed and deformed, and the upper rubber member 45 is fitted into the space above the lower rubber member 35. When the upper mating portion 42 is further rotated toward the lower mating portion 33, the lower surface 45a of the upper rubber member 45 approaches the upper surface 35a of the lower rubber member 35, and then, as shown in FIG. , 35 abut. In this state, the mass 51 is fixed to the straight portion of the downstream high-pressure fuel pipe by tightening the bolt 51 into the nut 36. This completes the attachment of the mass 21 to the straight portion of the downstream high-pressure fuel pipe. FIG. 5 shows a state in which the upper mating portion 42 is rotated and brought into contact with the lower mating portion 33 without sandwiching the straight portion of the downstream high pressure fuel pipe. The straight section of the tube is not shown.

  As shown also in FIG. 8, in the common rail fuel injection device 3 of the first embodiment, the fuel inlets of the injectors 9A to 9D are covered with metal straight tubular pipes 11A, 11B, 11C, and 11D. Flare nuts 12A, 12B, 12C, and 12D are provided at the ends of the straight pipes 11A to 11D. The flare nuts 12A to 12D connect the downstream high-pressure fuel pipes 7A to 7D and the straight pipes 11A to 11D. And each linear part 13A, 13B, 13C, 13D exists in the downstream high pressure fuel pipes 7A-7D near each flare nut 12A-12D.

  The mass 21 is independently attached to each of the linear portions 13A to 13D. Since the mass material 21 is attached to the straight portions 13A to 13D in the same manner, the straight portion 13A will be described as a representative example. FIG. 9 shows the first cylinder injector 9A and the downstream high pressure coupled to the injector 9A. It is the schematic which shows a connection part with 7A of fuel pipes. As shown in FIG. 9, after the straight portion 13A of the downstream high-pressure fuel pipe is disposed in the recesses 45b, 35b of the upper and lower rubber members 45, 35, the entire mass 21 is pressed against the flare nut 12A and held. In this state, the bolt 51 is inserted from above into the two holes 42a and 33a, screwed into the nut 36, and tightened. As a result, the mass 21 can be mounted with good workability on the end surface of the injector 9A side in the straight portion 13A of the downstream high-pressure fuel pipe 7A.

  The straight tubular pipes 11A to 11D shown in FIGS. 8 and 9 are not provided in the first and second comparative examples. 1st Embodiment mounts | wears with the mass 21 on the premise of the common rail type fuel-injection apparatus 3 which has the straight pipes 11A-11D. When mounting the mass 21 of the first embodiment, it is not always necessary to have the straight pipes 11A to 11D. The present invention can also be applied to the common rail fuel injection device 3 that does not include the straight pipes 11A to 11D.

  Next, FIG. 10 shows the vibration acceleration with respect to the frequency when the mass 21 is attached to each of the straight portions 13A to 13D of the downstream high-pressure fuel pipe with respect to the common rail fuel injection device 3 provided in a specific engine. It shows the characteristic, that is, the resonance frequency. Here, the “certain engine” is an engine in which the mass object of the first embodiment is to be mounted among the same in-line four-cylinder engines as shown in FIG. The broken line is the characteristic before the mass 21 is mounted, and the solid line is the characteristic after the mass 21 is mounted.

  As indicated by broken lines in the upper four stages of FIG. 10, the four resonance frequencies before mounting the mass 21 are predetermined values a1, b1, c1, and d1, and are different in the four vibration systems. As the input vibration, second-order, fourth-order, sixth-order, and eighth-order are generally used as shown in the lowermost stage of FIG.

  Now, in each vibration system of the No. 1 cylinder injector and No. 4 cylinder injector, by attaching the mass 21, the resonance frequency shifts to a smaller side from the predetermined value a 1, d 1 to the predetermined value a 2, d 2, and at the resonance frequency. The peak of the vibration acceleration is reduced from the predetermined values e1, h1 to the predetermined values e2, h2. In this case, if there is a limit vibration acceleration at the illustrated position, in each vibration system of the first cylinder injector and the fourth cylinder injector, the vibration acceleration at the resonance frequencies a2 and d2 can be obtained by attaching the mass 21. Peaks e2 and h2 can be less than the limit vibration acceleration. Here, the “limit vibration acceleration” is a limit vibration acceleration that can guarantee the functions of the injectors 9A to 9D as described above, and is determined in advance by the manufacturer of the injector.

  On the other hand, even in the vibration system of the No. 2 cylinder injector and No. 3 cylinder injector, the resonance frequency is shifted to the smaller side from the predetermined values b1 and c1 to the predetermined values b2 and c2 by mounting the mass 21. However, even if the resonance frequency moves to a smaller side, the vibration acceleration peaks f2 and g2 at the resonance frequencies b2 and c2 are the vibration acceleration peaks f1 and g1 at the resonance frequencies b1 and c1 before the mass 21 is mounted. On the contrary, it is rising. In this case, if there is a limit vibration acceleration at the position shown in the figure, in each vibration system of the second cylinder injector and the third cylinder injector, the vibration acceleration at the resonance frequencies b2 and c2 can be achieved by mounting the mass 21. On the contrary, the peaks f2 and g2 exceed the limit vibration acceleration. The reason is considered as follows. That is, the resonance frequency b2 after the mass 21 is attached to the vibration system of the No. 2 cylinder injector and the resonance frequency c2 after the mass 21 is attached to the vibration system of the No. 3 cylinder injector are the same. Yes. Moreover, the coincident resonance frequencies b2 and c2 overlap with the peak of the fourth-order input vibration. Therefore, in the vibration system of the No. 2 cylinder injector and No. 3 cylinder injector, the peak of vibration acceleration at the resonance frequencies b2 and c2 after mounting the mass 21 is increased due to the influence of the fourth-order input vibration. Conceivable.

  For this reason, the mass 21 is not mounted in each vibration system of the second cylinder injector and the third cylinder injector. By not mounting, the vibration acceleration peaks f1 and g1 at the resonance frequencies b1 and c1 can be made less than the limit vibration acceleration in the vibration systems of the second cylinder injector and the third cylinder injector.

  As a result, in the specific engine, as shown in FIG. 11, the straight portion 13A of the downstream high-pressure fuel pipe 7A coupled to the first cylinder injector 9A and the downstream high-pressure fuel pipe coupled to the fourth cylinder injector 9D. The mass 21 is mounted on the 7D straight portion 13D. On the other hand, the mass 21 is not attached to the straight portion 13B of the downstream high-pressure fuel pipe 7B coupled to the second cylinder injector 9B and the straight portion 13C of the downstream high-pressure fuel pipe 7C coupled to the third cylinder injector 9C. Here, FIG. 11 is a schematic view of a portion where the four injectors 9A to 9D and the common rail 6 are connected via the downstream high-pressure fuel pipes 7A to 7D to show the mounting of the mass object in the case of a specific engine. is there.

  As described above, in this embodiment, since the resonance frequency of each vibration system can be easily changed for each of the four vibration systems, whether or not the mass 21 is attached to each of the four vibration systems is matched in advance. Determined by Here, it is assumed from FIG. 11 that it is decided to attach the mass 21 to the two vibration systems of the first cylinder injector and the fourth cylinder injector. Then, after deciding to install the two vibration systems, the resonance frequency of each of the two vibration systems becomes the side where the vibration frequency decreases, and the two (plural) vibration systems of the first cylinder injector and the fourth cylinder injector The mass of the mass 21 is set so that the resonance frequencies are not the same. The condition that the resonance frequencies of the multiple vibration systems are not the same is that the input frequency is the same when the resonance frequencies of the multiple vibration systems are not the same. This is to eliminate the influence of vibration.

  Next, as shown in FIG. 11, when each mass 21 is attached to the two vibration systems of the first cylinder injector and the fourth cylinder injector, each mass 21 has the same shape and weight. . The reason is as follows. That is, by making the shape and weight of the mass 21 different between the two vibration systems of the first cylinder injector and the fourth cylinder injector, the peak of the vibration acceleration at the resonance frequency of the two vibration systems is made less than the limit vibration acceleration. Can do. However, if the shape and weight of the mass 21 are made different between the two vibration systems of the first cylinder injector and the fourth cylinder injector, management of the mass 21 for each vibration system is required, and the number of assembly steps increases accordingly. Moreover, even if the mass 21 is managed for each vibration system, the mass 21 for the vibration system of the No. 1 cylinder injector and the mass 21 for the vibration system of the No. 4 cylinder injector are mistaken (incorrect assembly occurs). I can't avoid that. Therefore, the masses 21 to be mounted on the two vibration systems of the No. 1 cylinder injector and the No. 4 cylinder injector are all of the same shape and weight so as to prevent erroneous assembly and increase the number of assembling steps. To do.

  Here, the effect of this embodiment is demonstrated.

  In this embodiment, the injectors 9A to 9D for each cylinder are coupled to the downstream high pressure fuel pipes 7A to 7D branched from the common rail 6, and the common rail fuel of the engine in which the injectors 9A to 9D for each cylinder are mounted on the cylinder head 2 is used. The injection device 3 is assumed. And the mass 21 is mounted | worn for every linear part 13A, 13B, 13C, 13D of the downstream high pressure fuel pipes 7A-7D couple | bonded with injector 9A-9D. According to this embodiment, it is caused by fuel injection from the injectors 9A to 9D only by retrofitting the mass 21 for each of the straight portions 13A to 13D of the downstream high pressure fuel pipes 7A to 7D whose specifications are already determined. Resonance can be reduced. In other words, any vehicle equipped with an engine having the common rail fuel injection device 3 of any specification can be handled without changing the specifications of the parts constituting the common rail fuel injection device 3. As a result, the vehicle types to which the present invention can be applied can be expanded.

  In the present embodiment, when the vibration acceleration at the resonance frequency of the vibration system including the injectors 9A to 9D and the downstream high-pressure fuel pipes 7A to 7D coupled to the injectors exceeds the limit vibration acceleration (predetermined vibration acceleration). The mass 21 is attached only to This effectively suppresses resonance that occurs in a vibration system in which the vibration acceleration at the resonance frequency exceeds the limit vibration acceleration LMT.

  When the mass 21 is attached to each of the straight portions 13A to 13D of the downstream high-pressure fuel pipes 7A to 7D coupled to the injectors 9A to 9D, the vibration acceleration of the vibration system after the mass 21 is attached becomes the limit vibration acceleration LMT ( The vibration acceleration (predetermined vibration) may be exceeded. In this embodiment, the mass 21 is not attached when the vibration acceleration at the resonance frequency of the vibration system after attachment exceeds the limit vibration acceleration. Accordingly, it is possible to avoid that the vibration acceleration at the resonance frequency of the vibration system after mounting exceeds the limit vibration acceleration by mounting the mass 21.

  In this embodiment, the predetermined vibration acceleration is the limit vibration acceleration LMT (the limit vibration acceleration that can guarantee the function of the injector). As a result, the function of each of the four injectors 9A to 9D can be assured even if resonance occurs with an impact input caused by the seating of a needle valve generated when fuel is injected from each of the four injectors 9A to 9D. .

  There is a method of separately preparing mass objects 21 having different shapes and masses for each vibration system so that the vibration acceleration of each of the four vibration systems is equal to or less than the limit vibration acceleration LMT. However, this method can be mistakenly assembled at the factory. Further, if the shape and mass of the mass 21 are different for each of the four vibration systems, it is necessary to be careful not to make a mistake when assembling, so that the time required for assembling becomes longer. On the other hand, according to the present embodiment, the mass objects 21 to be mounted for the respective straight portions 63A to 63D of the downstream high pressure fuel pipes 7A to 7D are all of the same shape and mass. By using all the masses 21 having the same shape and mass, it is possible to eliminate the problem of incorrect assembly. And since the mass 21 which has the same shape and mass is mounted | worn, the time at the time of an assembly | attachment can be shortened.

  According to the present embodiment, the mass of the mass 21 is on the side where the resonance frequency of the vibration system composed of the injectors 9A to 9D and the downstream high-pressure fuel pipes 7A to 7D to which the injectors 9A to 9D are coupled decreases. In addition, the resonance frequencies of the plurality of vibration systems are set so as not to be the same. Accordingly, even when the mass 21 having the same shape and mass is mounted, resonance caused by fuel injection from the injectors 9A to 9D can be reduced.

  According to the present embodiment, the mass 21 is composed of two members 31 and 41 (two metal members), a coupling mechanism (34a, 43, and 44), and a bolt 51. Here, the two members 31 and 41 are formed of plate-like members and can sandwich the straight portions 13A to 13D of the downstream high-pressure fuel pipes 7A to 7D. The said connection mechanism (34a, 43, 44) connects the end of the two members 31 and 41 so that it can move mutually. The bolt 51 can be inserted into the other end of the two members 31 and 41 to fasten the two members 31 and 41. As a result, the mass of the mass 21 can be changed simply and inexpensively by simply changing the length of the bolt 51.

  When setting so that the resonance frequency of the vibration system including the injectors 9A to 9D and the downstream high-pressure fuel pipes 7A to 7D coupled to the injectors is reduced, and the resonance frequencies of the plurality of vibration systems are not the same. For this, it is necessary to adapt the mass 21 by changing the mass of the mass 21. In this case, according to the present embodiment, the two members 31, 41, the connecting mechanism (34a, 43, 44) for connecting the ends of the two members 31, 41 so as to move relative to each other, and the two member materials 31 are provided. , 41, and a bolt 51 that can be inserted into the other end of the two members 31 and 41 and tightened. Then, by changing the length of the bolt 51, the resonance frequency of the vibration system including the injectors 9A to 9D and the downstream high-pressure fuel pipes 7A to 7D to which the injectors 9A to 9D are coupled is reduced, and Set so that the resonance frequencies of the plurality of vibration systems are not the same. Accordingly, it is possible to cope with this by simply selecting the optimum bolt from a single type of bolt 51 that differs only in the commercially available length. That is, it is possible to cope with a change in mass by changing only the length of the commercially available bolt 51. Since a commercially available bolt 51 can be used, an increase in cost can be suppressed.

  Since the two members 31 and 41 are metal members, the straight portions 63A to 63D are not damaged when the straight portions 63A to 63D of the downstream high-pressure fuel pipes 7A to 7D are sandwiched and fixed by the two members 31, 41. Thus, it is necessary to attach a mass object, and it takes time and workability is deteriorated. On the other hand, according to this embodiment, the rubber member 35 that protrudes beyond the width of the two members 31 and 41 on the side of the two members 31 and 41 that can sandwich the straight portions 13A to 13D of the downstream high-pressure fuel pipes 7A to 7D. , 45. As a result, the upper and lower rubber members 35 and 45 act as cushioning materials, and the downstream high-pressure fuel pipes 7A to 7D are brought into contact with the downstream high-pressure fuel pipes 7A to 7D, which are metal members as well as the two members 31 and 41. Can prevent scratches. Also, workability in the factory is improved.

  In the embodiment, the lower rubber member 35 protrudes on both sides of the U-shaped portion 32 (both sides in the vertical direction in FIG. 4), and the upper rubber member 45 is placed on both sides of the upper mating portion 42 (both sides in the vertical direction in FIG. 4). However, the present invention is not limited to this case. For example, the upper and lower rubber members 35 and 45 may be provided so as to protrude only on one side on the same side.

  In the embodiment, the description has been given of the case where the mass 21 is fixed to the straight portions 13A to 13D of the downstream high pressure fuel pipes 7A to 7D with the bolts 51. However, the present invention is not limited to this case. For example, the mass 21 may be fixed to the straight portions 13A to 13D of the downstream high-pressure fuel pipes 7A to 7D using a fastener other than a bolt. Further, the mass 21 may be fixed to the straight portions 13A to 13D of the downstream high pressure fuel pipes 7A to 7D using an adhesive.

DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder head 3 Common rail type fuel injection device (fuel injection device)
6 Common rail (common fuel supply passage)
7A, 7B, 7C, 7D Downstream high-pressure fuel pipe 9A, 9B, 9C, 9D Injector 13A, 13B, 13C, 13D Straight portion 21 Mass 31 Lower member (metal member)
35 Rubber member 36 Nut 41 Upper member (metal member)
45 Rubber member 51 Bolt

Claims (8)

In an engine fuel injection device in which an injector for each cylinder is coupled to a downstream high-pressure fuel pipe branched from a common fuel supply passage, and the injector for each cylinder is attached to a cylinder head.
A mass is attached to each straight portion of the downstream high-pressure fuel pipe coupled to the injector ,
The mass of the mass is on the side where the resonance frequency of the vibration system composed of the injector and the downstream high-pressure fuel pipe coupled to the injector decreases, and the resonance frequencies of the plurality of vibration systems are not the same. The engine fuel injection device that was set . 2. The mass object is mounted according to claim 1, wherein the mass object is attached only when vibration acceleration at a resonance frequency of a vibration system including the injector and a downstream high-pressure fuel pipe coupled to the injector exceeds a predetermined vibration acceleration. Engine fuel injection device. When the mass is attached to a vibration system composed of the injector and a downstream high-pressure fuel pipe coupled to the injector, the vibration acceleration at the resonance frequency of the vibration system after the mounting exceeds a predetermined vibration acceleration. The fuel injection device for an engine according to claim 1 or 2 , wherein the mass is sometimes not attached. The pre-fixed vibration acceleration is vibration acceleration limit that guarantees the function of the injector, a fuel injection device for an engine according to claim 2 or 3. Mass was to be attached to each linear portion of the downstream high-pressure fuel pipe are all of the same shape and mass, the fuel injection system for an engine according to any one of claims 1 to 4. The mass is
Two metal members formed of a plate-like member and sandwiching the straight portion of the downstream high-pressure fuel pipe;
A connection mechanism for connecting one end of the two metal members so as to move with respect to each other;
The composed of the two inserted into the other end of the metal member bolts may tighten the two members, the fuel injection system for an engine according to any one of claims 1 to 5. The mass is
Two metal members formed of a plate-like member and sandwiching the straight portion of the downstream high-pressure fuel pipe;
A connection mechanism for connecting one end of the two metal members so as to move with respect to each other;
A bolt that can be inserted into the other end of the two metal members and tighten the two members;
By changing the length of the bolt becomes a side where the resonance frequency of the vibration system is lowered, and the resonance frequency of the plurality of vibration systems have set the mass of the mass thereof so as not the same, according to claim 1 To 5. The fuel injection device for an engine according to any one of items 1 to 5 . Wherein the one of the two metal members side may sandwich the straight portion of the downstream high pressure fuel pipe, comprising a rubber member protruding from the width of the two metal members, a fuel injection device for an engine according to claim 6 or 7.

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