JP5243922B2 - Fuel injection device for internal combustion engine - Google Patents

Description

  The present invention relates to a fuel injection device for an internal combustion engine.

  An injection nozzle for injecting fuel into a cylinder of an internal combustion engine is attached to a cylinder head connected to a cylinder forming the cylinder. Among the fuel addition nozzles that inject and add fuel into the exhaust passage (hereinafter, both the injection nozzle and the fuel addition nozzle will be referred to as fuel injection nozzles) are those attached to the cylinder head. is there. This type of fuel injection nozzle is attached by being inserted into an attachment hole penetrating the cylinder head.

A configuration in which the fuel injection nozzle is inserted into the mounting hole and mounted is disclosed in Patent Document 1, for example. The insertion hole (attachment hole) is larger than the diameter of the small diameter hole portion penetrating the cylinder head, the diameter of the small diameter hole portion, and the medium diameter hole portion connected to the small diameter hole portion, and larger than the diameter of the medium diameter hole portion, And it consists of a large-diameter hole that opens to the outside of the cylinder head by connecting to the medium-diameter hole. A seal ring is attached to the nozzle body that enters the large-diameter hole, and a stepped ring made of copper is provided at the step between the medium-diameter hole and the small-diameter hole. The seal ring seals between the injector (fuel injection nozzle) and the insertion hole. The relative axial change based on the thermal expansion difference between the cylinder head and the injector is absorbed by the sliding of the small diameter portion of the stepped ring with respect to the small cylindrical portion of the stepped ring. Operation is ensured.
Utility Model Hei 3-1088859

  However, due to thermal deformation of the cylinder head, the hole diameter of the insertion hole becomes large, and the injector (fuel injection nozzle) may be inclined with respect to the insertion hole. When the injector (fuel injection nozzle) is inclined with respect to the insertion hole, the sealing performance by the seal ring is lowered.

  An object of this invention is to suppress the fall of the sealing performance between an attachment hole and a fuel-injection nozzle.

In the present invention, a mounting hole is provided in a cylinder head connected to a cylinder block forming a cylinder, and the mounting hole has a small diameter hole portion penetrating the cylinder head and a diameter of the small diameter hole portion. A medium-diameter hole portion that is large and connected to the small-diameter hole portion via a first hole step, and is larger than a diameter of the medium-diameter hole portion and connected to the medium-diameter hole portion via a second hole step. A large-diameter hole that opens to the outside of the cylinder head, and a fuel injection nozzle is inserted and attached to the attachment hole. The fuel injection nozzle is opposed to the first hole step. An internal combustion engine comprising a one nozzle step and a second nozzle step facing the second hole step, and a first seal member interposed between the first hole step and the first nozzle step A fuel injection device of claim In the present invention, an annular second seal member is interposed between the second hole step and the second nozzle step, and the second seal member includes the second hole step and the second nozzle step. and the step opposed portion which is interposed between said interposed between, or between the outer peripheral portion of the fuel injection nozzle and the in-diameter portion of the outer peripheral portion of the fuel injection nozzle and the large-diameter hole portion Rutotomoni , and a circumferential opposing portions of Ru extending from said stepped opposed portions in the axial direction of the fuel injection nozzle.

The 2nd seal member provided with the level | step difference installation part suppresses the inclination of the fuel injection nozzle with respect to an attachment hole, and suppresses the fall of the sealing performance between an attachment hole and a fuel injection nozzle.
In a preferred example, the second seal member includes a substrate and an elastic portion surface-bonded to the substrate, and the elastic portion includes a huge portion having a thickness larger than a basic thickness of the second seal member. I have.

The enormous portion is elastically deformed to seal between the mounting hole and the fuel injection nozzle.
In a preferred example, a plurality of protrusions are provided at equal intervals in the circumferential direction on the elastic portion provided on the circumferentially opposed placement portion.
In a preferred example, the enormous portion is provided at a position outside the periphery of the substrate.

A configuration in which the enormous portion is provided at a position outside the peripheral edge of the substrate is suitable for increasing the deformation amount of the enormous portion.
In a preferred example, the enormous portion is provided in the stepped portion.

The configuration in which the enormous portion is provided in the step-facing portion improves the sealing performance between the second hole step and the second nozzle step.
In a preferred example, the enormous portion is provided in the circumferentially opposed portion.

  The structure which provided the enormous part in the circumference | surroundings placement part improves the sealing performance between the inner periphery of an attachment hole, and a fuel-injection nozzle.

  The present invention has an excellent effect that a decrease in sealing performance between the mounting hole and the fuel injection nozzle can be suppressed.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1 (a), the diesel engine 10 (internal combustion engine) includes a plurality of cylinders 11, 12, 13, and 14 that accommodate pistons (not shown). A combustion chamber is defined in 14. Fuel injection nozzles 16, 17, 18, and 19 are attached to cylinder heads 15 connected to cylinder blocks (not shown) that form a plurality of cylinders 11, 12, 13, and 14, for each cylinder 11, 12, 13, and 14. It has been. The fuel (light oil) is supplied to the fuel injection nozzles 16, 17, 18, 19 via the fuel pump 20 and the common rail 21, and the fuel injection nozzles 16, 17, 18, 19 are connected to the cylinders 11, 12, 13, 19. Fuel is injected into the combustion chamber in 14.

  An intake manifold 22 is connected to the cylinder head 15. An intake pipe 23 is connected to the intake manifold 22, and an air cleaner 24 is connected to the intake pipe 23. A compressor unit 251 of the supercharger 25 is provided in the middle of the intake pipe 23. The supercharger 25 is a known variable nozzle turbocharger that is operated by an exhaust gas flow.

A throttle valve 26 is provided in the middle of the intake pipe 23. The throttle valve 26 is for adjusting the flow rate of air drawn into the intake pipe 23 via the air cleaner 24.
An exhaust manifold 28 is connected to the cylinder head 15. An exhaust pipe 29 is connected to the exhaust manifold 28. A post-treatment device 30 is provided on the exhaust pipe 29. As the aftertreatment device 30, an NOx storage reduction catalyst or a selective reduction NOx catalyst is used. Exhaust gas discharged from the cylinders 11, 12, 13, and 14 is discharged to the atmosphere via the exhaust manifold 28, the turbine unit 252 of the supercharger 25, the exhaust pipe 29, and the aftertreatment device 30.

  An intake port 31 and an exhaust port 32 are formed in the cylinder head 15 so as to communicate with the combustion chamber. A branch pipe portion 33 of the intake manifold 22 is connected to the intake port 31, and a branch pipe portion 34 of the exhaust manifold 28 is connected to the exhaust port 32.

  A fuel addition nozzle 35 is attached to the cylinder head 15. The fuel addition nozzle 35 is provided so as to face the exhaust port 32 of the cylinder 11. An addition pump 36 is connected to the fuel addition nozzle 35. The addition pump 36 supplies fuel to the fuel addition nozzle 35. The fuel addition nozzle 35 injects the supplied fuel into the exhaust port 32 of the cylinder 11. The fuel injection from the fuel addition nozzle 35 is performed when the NOx occlusion efficiency in the post-processing device 30 is reduced or before the NOx occlusion efficiency is reduced, and the NOx occluded in the NOx catalyst is reduced and purified. The addition pump 36 and the fuel addition nozzle 35 as fuel injection nozzles constitute fuel addition means for adding fuel to the post-processing device 30.

  As shown in FIG. 1B, the cylinder head 15 is provided with an attachment hole 37, and the fuel addition nozzle 35 is inserted and attached to the attachment hole 37. The attachment hole 37 includes a small-diameter hole 38 that penetrates the cylinder head 15, a medium-diameter hole 39 that is larger than the diameter of the small-diameter hole 38, and a large-diameter hole that is larger than the diameter of the medium-diameter hole 39. Part 40. The medium-diameter hole 39 is connected to the small-diameter hole 38 through the first hole step 41, and the large-diameter hole 40 that opens to the outside of the cylinder head 15 has a medium-diameter through the second hole step 42. It is connected to the hole 39.

  The fuel addition nozzle 35 includes a first nozzle step 43 that faces the first hole step 41 and a second nozzle step 44 that faces the second hole step 42. Between the first hole step 41 and the first nozzle step 43, an annular first seal member 45 made of rubber is interposed. The first seal member 45 seals between the first hole step 41 and the first nozzle step 43 in a state of being elastically deformed.

  An annular second seal member 46 is interposed between the second hole step 42 and the second nozzle step 44. The second seal member 46 is interposed between the stepped portion placement portion 47 interposed between the second hole step 42 and the second nozzle step 44, and between the large-diameter hole portion 40 and the outer peripheral portion of the fuel addition nozzle 35. And a circumferential counter 48.

  As shown in FIG. 2A, the second seal member 46 includes an iron-based substrate 49 and a rubber elastic portion 50 that is surface-bonded to one surface of the substrate 49. The elastic part 50 includes an enormous part 501 having a thickness T larger than the basic thickness t of the second seal member 46. The enormous portion 501 is provided at a position outside the periphery of the substrate 49, and is provided at the outer end of the stepped portion placement portion 47. The enormous portion 501 seals between the second hole step 42 and the second nozzle step 44 in a state of being elastically deformed.

  As shown in FIG. 2B, the elastic portion 50 in the circumferentially facing portion 48 is between the substrate 49 and the fuel addition nozzle 35, and a plurality of (four in this embodiment) protrusions are formed on the elastic portion 50. The strips 502 are provided at equal intervals in the circumferential direction. The plurality of protrusions 502 extending in the axial direction of the fuel addition nozzle 35 are elastically deformed and contact the outer peripheral portion of the fuel addition nozzle 35.

In the first embodiment, the following effects can be obtained.
(1) Even if the clearance between the second hole step 42 and the second nozzle step 44 is increased by the thermal deformation of the cylinder head 15, the enormous portion 501 that is elastically deformed follows the increase in the clearance. Therefore, the inclination of the fuel addition nozzle 35 with respect to the attachment hole 37 due to the thermal deformation of the cylinder head 15 is suppressed, and a decrease in the sealing performance between the attachment hole 37 and the fuel addition nozzle 35 is suppressed.

  (2) When the enormous portion is provided on the metal substrate 49, the thickness of the stepped portion 47 cannot be made smaller than the thickness of the substrate 49 even if the enormous portion is crushed and deformed. However, in the configuration in which the enormous portion 501 is provided at a position outside the periphery of the substrate 49, the thickness of the enormous portion 501 that has been crushed and deformed can be made equal to or less than the thickness of the substrate 49. In other words, the configuration in which the enormous portion 501 is provided at a position outside the peripheral edge of the substrate 49 increases the amount of elastic deformation of the enormous portion 501 and increases the clearance between the second hole step 42 and the second nozzle step 44. It is suitable for improving the followability of the enormous part 501 with respect to the above.

  (3) The plurality of protrusions 502 that are elastically deformed and are in contact with the outer peripheral portion of the fuel addition nozzle 35 contribute to suppression of the inclination of the fuel addition nozzle 35 with respect to the mounting hole 37 due to thermal deformation of the cylinder head 15.

Next, a second embodiment of FIG. 3 will be described. The same reference numerals are used for the same components as those in the first embodiment, and detailed description thereof is omitted.
The enormous portion 501 </ b> A provided in the rubber elastic portion 50 of the second seal member 46 </ b> A is provided at a position outside the peripheral edge of the substrate 49, and is provided at the outer end of the circumferential facing portion 48. . The enormous portion 501A seals between the large-diameter hole 40 and the outer peripheral portion of the fuel addition nozzle 35 in a state of being elastically deformed.

  Even if the clearance between the large-diameter hole portion 40 and the outer peripheral portion of the fuel addition nozzle 35 is increased by the thermal deformation of the cylinder head 15, the enormous portion 501A that is elastically deformed follows the increase in the clearance. Therefore, the inclination of the fuel addition nozzle 35 with respect to the attachment hole 37 due to the thermal deformation of the cylinder head 15 is suppressed, and a decrease in the sealing performance between the attachment hole 37 and the fuel addition nozzle 35 is suppressed.

Further, the same effect as the item (2) in the first embodiment can be obtained.
In the present invention, the following embodiments are also possible.
-You may use the 2nd sealing member provided with the enormous part 501 in 1st Embodiment and the enormous part 501A in 2nd Embodiment.

O You may use the 2nd seal | sticker part which a circumference | surroundings facing part exists between a medium diameter hole and the outer peripheral part of a fuel addition nozzle.
-You may use the 2nd seal member without a huge part.

A sealing member including a stepped portion and a circumferentially disposed portion may be provided between the first hole step 41 and the first nozzle step 43.
The present invention may be applied to the fuel injection nozzles 16 to 19 that inject fuel into the cylinders 11, 12, 13, and 14.

1 is a schematic configuration diagram of an internal combustion engine according to a first embodiment. FIG. 4B is a side sectional view showing the fuel addition nozzle 35. (A) is a partial expanded side sectional view. (B) is the sectional view on the AA line of Fig.2 (a). The partial expanded side sectional view which shows 2nd Embodiment.

Explanation of symbols

  11-14 ... cylinders. 15 ... Cylinder head. 35 ... Fuel addition nozzle. 351 ... outer periphery. 37: Mounting hole. 38: Small diameter hole. 39: Medium diameter hole. 40: Large diameter hole. 41 ... 1st hole level | step difference. 42: Second hole step. 43: First nozzle step. 44: Second nozzle level difference. 45. First seal member. 46, 46A, second seal member. 47: A stepped portion. 48. Circumferential placement part. 49. Substrate. 50: Elastic part. 501, 501A: Enormous parts. t: Base thickness. T: Thickness.

Claims (6)

A mounting hole is provided in a cylinder head connected to a cylinder block forming a cylinder. The mounting hole has a small-diameter hole that penetrates the cylinder head, a diameter larger than the diameter of the small-diameter hole, and the A medium diameter hole portion connected to the small diameter hole portion through a first hole step, and a cylinder head larger than the diameter of the medium diameter hole portion and connected to the medium diameter hole portion via a second hole step. A large-diameter hole opening on the outer side of the fuel injection nozzle, and a fuel injection nozzle is inserted and attached to the attachment hole, and the fuel injection nozzle has a first nozzle step facing the first hole step, And a second nozzle step opposite to the second hole step, and a fuel injection device for an internal combustion engine, wherein a first seal member is interposed between the first hole step and the first nozzle step. In
An annular second seal member is interposed between the second hole step and the second nozzle step, and the second seal member is interposed between the second hole step and the second nozzle step. and the step opposing portion interposed, the interposed between the large-diameter hole portion and between the outer peripheral portion of the fuel injection nozzle, or the in-diameter portion and the outer peripheral portion of the fuel injection nozzle Rutotomoni, the step fuel injection device for an internal combustion engine from the opposing portion and a circumferential opposing portions of Ru extending in the axial direction of the fuel injection nozzle.   The said 2nd seal member is provided with the board | substrate and the elastic part surface-coupled to the said board | substrate, The said elastic part is provided with the enormous part which has a thickness larger than the basic thickness of the said 2nd seal member. A fuel injection device for an internal combustion engine according to claim 1. The fuel injection device for an internal combustion engine according to claim 2, wherein a plurality of protrusions are provided at equal intervals in the circumferential direction on the elastic portion provided in the circumferentially opposed portion. 4. The fuel injection device for an internal combustion engine according to claim 2, wherein the enormous portion is provided at a position outside the periphery of the substrate. The fuel injection device for an internal combustion engine according to any one of claims 2 to 4 , wherein the enormous portion is provided in the stepped portion placement portion. The fuel injection device for an internal combustion engine according to any one of claims 2 to 4 , wherein the enormous portion is provided in the circumferentially facing portion.

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