Patent Grant
8225770
This application claims priority to Japanese Patent Application No. 2009-083749, filed on Mar. 30, 2009. The entire disclosure of Japanese Patent Application No. 2009-083749 is hereby incorporated herein by reference.
1. Field of the Invention
The present invention relates to a fuel injector assembly, a cylinder head side member, and a fuel injector installation method.
2. Background Information
An injector mounting structure is known (see Japanese Laid-Open Patent Publication No. 2006-90282) in which the injectors for injecting fuel into each of the cylinders of an engine and the fuel tubes for supplying fuel to the injectors are integrated into a single unit and the injector unit is mounted to a cylinder head main body by inserting the injectors into injector mounting holes formed in the cylinder head main body.
With this cylinder head apparatus, an O-ring is attached to a nozzle section of each of the injectors. The O-rings contact the injector mounting holes in an elastic fashion and prevent fuel from leaking out of the injector mounting holes.
In the injector mounting structure disclosed in Japanese Laid-Open Patent Publication No. 2006-90282, the O-rings undergo compressive deformation when the injectors are inserted into the injector mounting holes and a load resulting from the compression of the O-rings translates directly into an insertion load required to insert the injectors into the injector mounting holes.
With an injector unit comprising a plurality of injectors each having an O-ring is installed, all of the O-rings are compressed at substantially the same time. Consequently, the insertion load of the injectors becomes large and the task of mounting the injector unit becomes difficult.
An object of the present invention is to provide an injector mounting structure that can improve the installation performance of an injector unit. A means by which at least a portion of this object can be achieved will now be explained.
A fuel injector assembly according to one aspect of the present invention includes a modular fuel injector unit and a cylinder head side member. The modular fuel injector unit includes a first fuel injector with a first seal, a second fuel injector with a second seal and a fuel distribution pipe fluidly communicating with the first and second fuel injectors to distribute a fuel to the first and second fuel injectors, with the first and second fuel injectors and the fuel distribution pipe being coupled together as a single installable unit. The cylinder head side member includes a first insertion hole with a first fitting section that receives the first seal and a second insertion hole with a second fitting section that receives the second seal. The first and second insertion holes of the cylinder head side member and the first and second seals of the first and second fuel injectors are arranged with respect to each other such that as the modular fuel injector unit is being mounted to the cylinder head side member by inserting the first and second fuel injectors into the first and second insertion holes formed in the cylinder head side member, respectively, the first seal undergoes a maximum compressive deformation in the first fitting section at a time that does not coincide with a time that the second seal undergoes a maximum compressive deformation in the second fitting section.
With the fuel injector assembly according to the above described aspect of the present invention, a time when the first seal member undergoes a maximum compressive deformation in the first fitting section does not coincide with a time when the second seal member undergoes a maximum compressive deformation in the second fitting section. Consequently, the insertion load incurred when the modular fuel injector unit is installed onto a cylinder head side member can be reduced. As a result, the modular fuel injector unit can be installed more easily.
The cylinder head side member may include a cylinder head main body, an intake manifold attached to the cylinder head main body, and/or an adapter plate used to when the intake manifold is attached to the cylinder head main body.
The first and second insertion holes of the cylinder head side member and the first and second seals of the first and second fuel injectors may be arranged with respect to each other such that the second seal begins to undergo a compressive deformation in the second fitting section after the first seal has undergone a maximum compressive deformation in the first fitting section as the first and second fuel injectors are inserted into the first and second insertion holes, respectively.
Since the second seal member starts to undergo compressive deformation in the second fitting section after the first seal member has undergone a maximum compressive deformation in the first fitting section, the compressive deformation of the second seal member can be started after a maximum compressive load has been generated by the compressive deformation of the first seal member when the modular fuel injector unit is installed onto a cylinder head side member. In other words, the timings at which the insertion loads of the injectors reach their respective peaks when the modular fuel injector unit is installed onto the cylinder head side member can be offset from each other.
The first and second insertion holes of the cylinder head side member and the first and second seals of the first and second fuel injectors may be arranged with respect to each other such that the second seal begins to undergo a compressive deformation in the second fitting section after the first and second fuel injectors have been inserted simultaneously into the first and second insertion holes, respectively, by a prescribed stroke amount beyond a position where the first seal reached a maximum compressive deformation in the first fitting section. Since the second seal member starts to undergo compressive deformation in the second fitting section after the insertion load of the first seal member in the first insertion hole has decreased from a maximum insertion load, the insertion load incurred when the modular fuel injector unit is installed onto a cylinder head side member can be reduced more effectively.
The first and second insertion holes of the cylinder head side member and the first and second seals of the first and second fuel injectors may be arranged with respect to each other such that the prescribed stroke amount is preset to such a value that an insertion load imposed on the first insertion hole by the first fuel injector decreases from a maximum load state in which the insertion load is at a maximum load to a minimum load state in which the insertion load has decreased to a minimum load. In this way, the insertion load incurred when the modular fuel injector unit is installed onto a cylinder head side member can be reduced to the greatest degree possible.
The first fitting section may be located in the first insertion hole of the cylinder head side member at a position that is shallower along a depth direction of first insertion hole than a position of the second fitting section in the second insertion hole with respect to the depth direction of second insertion hole. In this way, the timings at which the insertion loads of the injectors reach their respective peaks when the modular fuel injector unit is attached to the cylinder head side member can be offset from each other by simply making the position where the first fitting section is formed shallower along a depth direction than the position where the second fitting section is formed.
The cylinder head side member may be part of a cylinder head main body that forms a part of the combustion chamber for a cylinder. The first and second insertion holes may be arranged with respect to the combustion chamber such that fuel is injected from both of the first and second fuel injectors into the same combustion chamber. In this way, the insertion load incurred when an injector unit having multiple injectors, e.g., a twin-injector type having two injectors arranged to inject fuel into each combustion chamber, is mounted to a cylinder head side member. As a result, even a twin-injector type modular fuel injector unit can be installed easily.
The modular fuel injector unit may further include at least one of an additional first fuel injector and an additional second fuel injector with the at least one of the additional first fuel injector and the additional second fuel injector fluidly communicating with the fuel distribution pipe. The cylinder head side member may further include at least one of an additional first insertion hole and an additional second insertion hole corresponding to the at least one of the additional first fuel injector and the additional second fuel injector. The cylinder head main body may include a plurality of combustion chambers arranged in a straight row, with the first and second insertion holes and the at least one of the additional first insertion hole and the additional second insertion hole of the cylinder head side member being arranged symmetrically with respect to a central perpendicular plane that is perpendicular to a direction along which the combustion chambers are arranged in the straight row and arranged to pass through a central position along the row of combustion chambers. Since the first insertion hole and the second insertion hole are arranged symmetrically with respect to a central perpendicular plane that is perpendicular to a direction along which the combustion chambers are arranged in a straight row and arranged to pass through a central position along the row of combustion chambers, the insertion load incurred when the modular fuel injector unit is installed can be distributed symmetrically with respect to the central perpendicular plane. As a result, the modular fuel injector unit can be installed even more easily.
The cylinder head side member may be part of a cylinder head main body that forms parts of a plurality of combustion chambers for cylinders that are arranged in a straight row. The first and second insertion holes may be arranged with respect to the combustion chambers such that fuel injected from the first and second fuel injectors are injected into different combustion chambers, respectively. Since the timings at which compression loads are generated when the seal members start to undergo compressive deformation can be varied among the combustion chambers, the insertion load incurred when the modular fuel injector unit is installed onto the cylinder head side member can be reduced. As a result, the modular fuel injector unit can be installed more easily.
The modular fuel injector unit may further include at least one of an additional first fuel injector and an additional second fuel injector with the at least one of the additional first fuel injector and the additional second fuel injector fluidly communicating with the fuel distribution pipe. The cylinder head side member may further include at least one of an additional first insertion hole and an additional second insertion hole corresponding to the at least one of the additional first fuel injector and the additional second fuel injector. The first and second insertion holes and the at least one of the additional first insertion hole and the additional second insertion hole of the cylinder head side member may be arranged symmetrically with respect to a central perpendicular plane that is perpendicular to a direction along which the combustion chambers are arranged in the straight row and arranged to pass through a central position along the row of combustion chambers. Since the first insertion hole and the second insertion hole are arranged symmetrically with respect to a central perpendicular plane that is perpendicular to a direction along which the combustion chambers are arranged in a straight row and arranged to pass through a central position along the row of combustion chambers, the insertion load incurred when the modular fuel injector unit is installed can be distributed symmetrically with respect to the central perpendicular plane. As a result, the modular fuel injector unit can be installed even more easily.
The first seal may be attached to the first fuel injector at a first position that is more forward than a position of the second seal of the second fuel injector with respect to an insertion direction in which the first fuel injector is inserted into the first insertion hole and the second fuel injector is inserted into the second insertion hole. As a result, the timings at which the insertion loads of the injectors reach their respective peaks when the modular fuel injector unit is installed onto the cylinder head side member can be offset from each other by simply varying the positions where the first seal member and the second seal member are attached.
A cylinder head side member according to another aspect of the present invention includes a first fuel injector mounting section and a second fuel injector mounting section. The first fuel injector mounting section includes a first insertion hole that is configured to receive a first fuel injector having a first seal. The second fuel injector mounting section includes a second insertion hole that is configured to receive a second fuel injector having a second seal. The first insertion hole is partially defined by a first fitting section configured to receive the first seal of the first fuel injector therein. The second insertion hole is partially defined by a second fitting section configured to receive the second seal of the second fuel injector therein. The first fitting section is located along an axial direction of the first insertion hole at a first axial position and the second fitting section is located along an axial direction of the second insertion hole at a second axial position with the first and second axial positions being arranged such that the first seal undergoes a maximum compressive deformation in the first fitting section at a time that does not coincide with a time that the second seal undergoes a maximum compressive deformation in the second fitting section as the first and second fuel injectors are inserted into the first and second insertion holes, respectively.
With a cylinder head side member according to the above described aspect of the present invention, the insertion load incurred when a modular fuel injector unit is attached to the cylinder head side member can be reduced because a positional relationship of the first fitting section formed in the first insertion hole and the second fitting section formed in the second insertion hole is such that when the first injector and the second injector are inserted, a time when the first seal member undergoes a maximum compressive deformation in the first fitting section does not coincide with a time when the second seal member undergoes a maximum compressive deformation in the second fitting section. As a result, the modular fuel injector unit can be installed more easily. The cylinder head side member includes a cylinder head main body, an intake manifold attached to the cylinder head main body, and an adapter plate used to when the intake manifold is attached to the cylinder head main body.
The first and second axial positions may be arranged such that the second seal begins to undergo a compressive deformation in the second fitting section after the first seal has undergone a maximum compressive deformation in the first fitting section as the first and second fuel injectors are inserted into the first and second insertion holes, respectively. By contriving the positional relationship of the first fitting section formed in the first insertion hole and the second fitting section formed in the second insertion hole such that the second seal member starts to undergo compressive deformation in the second fitting section after the first seal member has undergone a maximum compressive deformation in the first fitting section, the compressive deformation of the second seal member can be started after a maximum compressive load has been generated by the compressive deformation of the first seal member when the modular fuel injector unit is installed onto a cylinder head side member. In other words, the timings at which the insertion loads of the injectors reach their respective peaks when the modular fuel injector unit is installed onto the cylinder head side member can be offset from each other.
The first and second axial positions may be arranged such that the second seal begins to undergo a compressive deformation in the second fitting section after the first seal has undergone a maximum compressive deformation in the first fitting section as the first and second fuel injectors are inserted into the first and second insertion holes, respectively. Since the second seal member starts to undergo compressive deformation in the second fitting section after the insertion load of the first seal member in the first insertion hole has decreased from a maximum insertion load, the insertion load incurred when the modular fuel injector unit is installed onto a cylinder head side member can be reduced more effectively. The prescribed stroke amount may be set to such a value that an insertion load imposed on the first insertion hole by the first fuel injector decreases from a maximum load state in which the insertion load is at a maximum load to a minimum load state in which the insertion load has decreased to a minimum load. In this way, the insertion load incurred when the modular fuel injector unit is installed onto a cylinder head side member can be reduced to the greatest degree possible.
The first fitting section may be located in the first insertion hole of the cylinder head side member at a position that is shallower along a depth direction of first insertion hole than a position of the second fitting section in the second insertion hole with respect to the depth direction of second insertion hole. In this way, the timings at which the insertion loads of the injectors reach their respective peaks when the modular fuel injector unit is attached to the cylinder head side member can be offset from each other by simply making the position where the first fitting section is formed shallower along a depth direction than the position where the second fitting section is formed.
The first insertion hole may be partially defined by a first tapered section that is formed at a rearward end of the first fitting section of the first insertion hole with respect to an insertion direction in which the first fuel injector is inserted into the first insertion hole with the first tapered section gradually increasing in diameter in a rearward direction towards an entrance opening of the first insertion hole. The second insertion hole may be partially defined by a second tapered section that is formed at a rearward end of the second fitting section of the second insertion hole with respect to an insertion direction in which the second fuel injector is inserted into the second insertion hole with the second tapered section gradually increasing in diameter in a rearward direction towards an entrance opening of the second insertion hole. In this way, the compressive deformation of the seal members can be made to occur gradually and the injectors can be inserted more easily.
Referring now to the attached drawings which form a part of this original disclosure:
Selected embodiments will now be explained with reference to the drawings. It will be apparent to those skilled in the art from this disclosure that the following descriptions of the embodiments are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
As shown in
As shown in
As shown in
A depth A of the tapered section 16a of an insertion hole 16 is smaller than a depth B of the tapered section 17a of an insertion hole 17. That is, the position where the fitting section 16b of an insertion hole 16 starts is shallower in a depth direction than the position where the fitting section 17b of an insertion hole 17 starts. The depths A and B are set such that a seal ring 21 arranged on an injector 8 entering an insertion hole 17 starts to undergo compressive deformation in the fitting section 17b when the injector unit 30 has been pushed toward the cylinder head 3 beyond a point where a seal ring 21 arranged on an injector 8 entering an insertion hole 16 reached a maximum compressive deformation in the fitting section 16b (i.e., a point where an insertion load required to insert the injector 8 into the insertion hole 16 reached a maximum value) and has reached a point where the insertion load required to insert the injector 8 into the insertion hole 16 has decreased as much as it will.
In this embodiment, the depth B is set based on an insertion load curve indicating how the insertion load changes when one injector 8 is inserted into an insertion hole 16. The insertion load curve is obtained in advance experimentally. A stroke amount ΔS is measured from a position on the insertion load curve where the insertion load of the injector 8 begins to occur to a position where the insertion load has decreased from a peak insertion load F to a load corresponding to a friction force of the seal ring 21 (described later). The depth B is set to a value equal to the sum of the stroke amount ΔS and the depth A. An example of an insertion load curve is shown in
As shown in
As shown in
As shown in
What occurs during the process of installing an injector unit 30 onto a cylinder head 3 using an injector mounting structure according to the embodiment will now be explained.
When the stroke amount S reaches the value S1, the compressive deformation of the seal rings 21 inside the insertion holes 16 is at a maximum and the insertion force required to insert the injectors 8 into the insertion holes 16 is at a peak value F1′. At this stage, a majority of each of the seal rings 21 in the insertion holes 16 has been compressed to substantially the same diameter as the fitting section 16b (
When the stroke amount S reaches the value S3, the compressive deformation of the seal rings 21 inside the insertion holes 17 is at a maximum and the insertion force required to insert the injectors 8 into the insertion holes 17 is at a peak value F2. At this stage, the insertion force begins to decrease because a majority of each of the seal rings 21 in the insertion holes 17 has been compressed to substantially the same diameter as the fitting section 17b and further insertion merely compresses the remainder of each of the seal rings 21 to substantially the same diameter as the fitting sections 17b (this stage corresponds to a section of
The broken-line curve shown in
With the fuel injector assembly for an injector unit 30 according to the embodiment described above, the timing at which the insertion forces of the injectors 8 inserted into the insertion holes 16 reach a peak a is different from the timing at which the insertion forces of the injectors 8 inserted into the insertion holes 17 reach a peak b. Consequently, the insertion load incurred when attaching the injector unit 30 to the cylinder head 3 can be reduced. Since an insertion load begins to be incurred by the injectors 8 inserted into the insertion holes 17 when the insertion load of the injectors 8 inserted into the insertion holes 16 has decreased from a maximum insertion load to a load approximately equal to a friction force of the seal rings 21, the insertion load incurred when attaching the injector unit 30 to the cylinder head 3 can be reduced even more effectively. Also, the timing at which the insertion forces of the injectors 8 inserted into the insertion holes 16 reach a peak a can easily be offset from the timing at which the insertion forces of the injectors 8 inserted into the insertion holes 17 reach a peak b by simply making the position where the fitting section 16b of each of the insertion holes 16 starts shallower in a depth direction than the position where the fitting section 17b of each of the insertion holes 17 starts.
With the fuel injector assembly for an injector unit 30 according to the embodiment described above, the insertion holes 16 and 17 are arranged in the cylinder head 3 to be symmetrical with respect to a central perpendicular plane P that is perpendicular to a direction along which the cylinders are arranged in a straight row and arranged to pass through a central position along the row of four combustion chambers 12. Consequently, the insertion load incurred when the injector unit 30 is attached to the cylinder head 3 can be distributed symmetrically with respect to the central perpendicular plane P. That is, when the injector unit 30 is attached to the cylinder head 3, the injector unit 30 does not become slanted with respect to the direction in which the cylinders are arranged. As a result, the modular fuel injector unit can be installed even more easily.
In the fuel injector assembly for an injector unit 30 according to the embodiment described above, the insertion holes 16 and 17 corresponding to each of the first cylinder 14a and the second cylinder 14b are arranged with the insertion hole 16 on the left and the insertion hole 17 on the right when viewed as shown in
In the fuel injector assembly for an injector unit 30 according to the embodiment described above, the insertion holes 16 and 17 are symmetrical with respect to a central perpendicular plane P that is perpendicular to a direction along which the cylinders are arranged in a straight row and passes through a central position along the row of four combustion chambers 12. However, it is acceptable for the insertion holes to have an asymmetrical arrangement with respect to such a plane. For example,
Although the number of insertion holes 16 provided in the cylinder head 3 is the same as the number of insertion holes 17 in the mounting structure of an injector unit 30 according to the embodiment described above, it is acceptable for the number of each type of insertion hole to be different. For example,
Although the fuel injector assembly for an injector unit 30 is applied to a four-cylinder engine in the embodiment described above, there are no limitations on the number of cylinders, i.e., any number of cylinders is acceptable.
Although in the embodiment the fuel injector assembly for an injector unit 30 is applied to a twin-injector type engine 1 having a pair of insertion holes 16 and 17 formed in each of the intake passages 6, the present invention can also be applied to a conventional engine having only one insertion hole per intake passage.
In the fuel injector assembly for an injector unit 30 according to the embodiment described above, the timing at which the insertion forces of the injectors 8 inserted into the insertion holes 16 reach a peak a is offset from the timing at which the insertion forces of the injectors 8 inserted into the insertion holes 17 reach a peak b by forming the insertion holes 16 and 17 such that the position where the fitting section 16b of each of the insertion holes 16 starts is shallower in a depth direction than the position where the fitting section 17b of each of the insertion holes 17 starts. However, it is also acceptable to make the start position of the fitting sections 16b in the insertion holes 16 the same as the start position of the fitting sections 17b in the insertion holes 17 (i.e., make the insertion holes 16 and the insertion holes 17 have exactly the same shape) and, instead, vary the positions where the ring grooves 8d for attaching the seal rings 21 are formed on the injectors 8. In this way, too, the timing at which the insertion forces of the injectors 8 inserted into the insertion holes 16 reach a peak a can be offset from the timing at which the insertion forces of the injectors 8 inserted into the insertion holes 17 reach a peak b.
The injectors 608 and 609 are arranged in the cylinder head in positions symmetrical with respect to a central perpendicular plane that is perpendicular to a direction along which the cylinders are arranged in a straight row and passes through a central position along a row of four combustion chambers. More specifically, the injectors 608 and 609 corresponding to each of a first cylinder and a second cylinder are installed in fuel distribution pipes with the injector 608 on the first cylinder side and the injector 609 on the second cylinder side, and the injectors 608 and 609 corresponding to each of a third cylinder and a fourth cylinder are installed in fuel distribution pipes with the injector 609 on the third cylinder side and the injector 608 on the fourth cylinder side.
With a fuel injector assembly according to this variation, the timing at which the insertion forces of the injectors 608 reach a peak is different from the timing at which the insertion forces of the injectors 609 reach a peak when the injectors 608 and 609 are pushed into the insertion holes. Consequently, the insertion load incurred when attaching the injector unit to the cylinder head can be reduced.
In a fuel injector assembly for an injector unit 30 according to the previously described embodiment, the position where the fitting section 16b of each of the insertion holes 16 starts is shallower in a depth direction than the position where the fitting section 17b of each of the insertion holes 17 starts and, consequently, the timing at which the insertion forces of the injectors 8 inserted into the insertion holes 16 reach a peak a is different from the timing at which the insertion forces of the injectors 8 inserted into the insertion holes 17 reach a peak b. However, it is also acceptable to vary the timings at which the insertion forces of the injectors inserted into the respective insertion holes reach their respective peaks by varying the start positions of the insertion holes as a whole.
As shown in
In a fuel injector assembly for an injector unit 30 according to the previously described embodiment, each of the eight insertion holes is formed to one of two different depths. However, it is also acceptable for all eight of the insertion holes to have a different depth than the others.
Although in a fuel injector assembly for an injector unit 30 according to the previously described embodiment the insertion holes 16 and 17 are formed in the cylinder head 3, it is also acceptable for the insertion holes to be formed in an intake manifold (not shown) that connects to the intake passages of the cylinder head 3 or in an adapter plate (not shown) fastened between the cylinder head 3 and an intake manifold.
In understanding the scope of the present invention, the term “comprising” and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, integers, and/or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers and/or steps. The foregoing also applies to words having similar meanings such as the team, “including”, “having” and their derivatives. Also, the terms “part,” “section,” “portion,” “member” or “element” when used in the singular can have the dual meaning of a single part or a plurality of parts. Also as used herein to describe the above embodiments, the following directional terms “forward”, “rearward”, “above”, “downward”, “vertical”, “horizontal”, “below” and “transverse” as well as any other similar directional team refer to those directions of an internal combustion engine equipped with the fuel injector assembly when the internal combustion engine is oriented as shown in
While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. For example, the size, shape, location or orientation of the various components can be changed as needed and/or desired. Components that are shown directly connected or contacting each other can have intermediate structures disposed between them. The functions of one element can be performed by two, and vice versa. The structures and functions of one embodiment can be adopted in another embodiment. It is not necessary for all advantages to be present in a particular embodiment at the same time. Every feature which is unique from the prior art, alone or in combination with other features, also should be considered a separate description of further inventions by the applicant, including the structural and/or functional concepts embodied by such feature(s). Thus, the foregoing descriptions of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
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