JP2001207940A - Fuel injection type engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of parts and to improve assembling workability by forming a fuel rail 45 integrally with an intake manifold 21, preventing fuel from being heated. SOLUTION: The intake manifold 21 is formed by a downstream side manifold 22 and an upstream side manifold 23. In the downstream side manifold 22, a mounting seat 28 for fitting and holding one end part on a fuel injection port side of an injector 24 is formed. The upstream side manifold 23 is integrally provided with the fuel rail 45 and a holding hole 50 for fitting and holding the other end part on a fuel entrance side of the injector 24 is formed. Fuel is forcibly fed to the holding hole 50 from a fuel passage within the fuel rail 45.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection engine having an injector mounted on an intake manifold.

[0002]

2. Description of the Related Art Conventionally, in order to attach an injector to an intake manifold in this type of engine, for example, a structure disclosed in Japanese Utility Model Laid-Open No. 7-10463 may be employed. The intake manifold disclosed in this publication has an L-shape by a laterally extending portion extending laterally from the engine and a longitudinally extending portion extending upward from the upstream end of the laterally extending portion toward the engine. And an intake chamber is integrally formed at an upstream end of the longitudinally extending portion.

[0003] The injector holds the fuel injection port side end in a state where the axial direction is inclined obliquely upward at the engine side end of the laterally extending portion, and the fuel inlet side end is A bracket protruding from the laterally extending portion toward the intake chamber is held via a fuel rail. The fuel injection port side end is held by the laterally extending portion via an elastic seal member. The fuel rail has a structure in which a fuel passage through which fuel is pumped is formed, and a hole for inserting a fuel inlet side end of an injector is formed, and the hole communicates with the fuel passage. The bracket is fixed to the bracket by a fixing bolt in a state where a pressing force is applied to the injector so as to press the seal member. The fuel rail is disposed between the lateral extension and the intake chamber.

[0004]

However, if the above-described injector mounting structure is employed, there is a problem that the assemblability of the intake manifold is reduced. The fuel rail is disposed in a narrow space surrounded by a laterally extending portion and a longitudinally extending portion of an intake manifold and an intake chamber. , And the nut for fixing the fuel rail must be fastened.

In order to improve the assemblability of an intake manifold having a structure in which an injector is mounted, a relatively small fuel rail is formed integrally with the intake manifold as disclosed in, for example, Japanese Patent Application Laid-Open No. 8-334070. It is conceivable to reduce the number of parts. In the intake manifold described in this publication, a fuel rail is formed integrally with a laterally extending portion extending laterally from the engine so as to be located near an upstream side of an injector mounting portion, and the fuel rail and a fuel inlet of the injector are formed. The side ends are connected by a U-shaped fuel passage forming joint.

However, disposing the fuel rail in the vicinity of the injector as described above causes a new problem that the fuel in the fuel rail is heated by the heat of the engine conducted through the intake manifold.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a fuel rail is formed integrally with an intake manifold while preventing fuel from being heated. The purpose is to improve the performance.

[0008]

In order to achieve this object, a fuel injection engine according to the present invention comprises a downstream manifold having a mounting seat for fitting and holding one end of an injector on the side of a fuel injection port. An intake manifold is formed by the upstream manifold attached to the upstream end of the downstream manifold, and a fuel rail is integrally provided on the upstream manifold, and the other end of the injector on the fuel inlet side is fitted and held. A hole is formed, and fuel is pressure-fed to the holding hole from a fuel passage in the fuel rail.

According to the present invention, a state in which the fuel injection port end of the injector is fitted to the mounting seat of the downstream manifold and the fuel inlet side end of the injector is fitted to the holding hole of the upstream manifold. By connecting the two manifolds with each other, the connection between the injector and the fuel rail and the fixing of the injector can be performed simultaneously. For the portion where the downstream manifold and the upstream manifold are connected to each other, a simple fastening structure in which flanges provided at the ends of the manifold are fastened with bolts and nuts can be employed. In addition, since the connecting portion between the downstream manifold and the engine is interposed in the heat transfer path between the upstream manifold having the fuel rail and the engine, it is necessary to increase the thermal resistance between the engine and the upstream manifold. Can be.

A fuel injection engine according to a second aspect of the present invention is the fuel injection engine according to the first aspect of the present invention, wherein a surge tank and a seat for attaching a throttle valve are integrally formed in an upstream manifold. The upstream manifold is supported via a bracket on one side where the intake system of the engine is located, and an intake device having a throttle valve attached to the upstream manifold is supported on the other side of the engine. is there. According to the present invention, the upstream manifold can be supported by the two sides of the engine, and the support of the upstream manifold is stabilized, so that the displacement of the upstream manifold with respect to the downstream manifold due to engine vibration is prevented. Can be blocked.

A fuel injection engine according to a third aspect of the present invention is the fuel injection engine according to the first or second aspect of the invention, wherein the fuel rail is formed integrally with the upstream manifold. is there. According to the present invention, the number of assembly steps and the number of parts can be reduced as compared with the case where the fuel rail is formed separately from the upstream manifold.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a fuel injection type engine according to the present invention will be described below in detail with reference to FIGS. FIG. 1 is a sectional view of a fuel injection type engine according to the present invention, and FIG. 2 is a plan view of the same, showing the cylinder head in a partially broken state. FIG. 3 is a cross-sectional view of the intake manifold taken along line III-III of FIG. 2, and FIG. 4 is an enlarged cross-sectional view showing an injector mounting portion.

In these figures, the reference numeral 1 indicates a water-cooled four-cycle two-cylinder engine according to this embodiment. Reference numeral 2 denotes a cylinder body of the engine 1, 3 denotes a piston, 4 denotes a connecting rod, 5 denotes a cylinder head, and 6 denotes a head cover. The cylinder body 2 is mounted on a crankcase (not shown) having a well-known structure. The piston 3 is connected via a connecting rod 4 to a crankshaft supported on the crankcase.

The cylinder head 5 has an intake port 7 extending linearly obliquely upward and leftward in FIG. 1 from the combustion chamber S, and an exhaust port 7 extending upward and rightward from the combustion chamber S in FIG. 8 are formed. Both ports 7, 8 are opened and closed by two intake valves 9 and two exhaust valves 10 per cylinder. The intake valve 9 and the exhaust valve 10 have a structure driven by a so-called DOHC type valve train 11. Reference numeral 12 denotes an intake cam shaft for driving the intake valve 9, reference numeral 13 denotes an exhaust cam shaft for driving the exhaust valve 10, and reference numeral 14 denotes both of the cam shafts 12, 14.
1 shows a valve lifter interposed between a valve 13 and intake / exhaust valves 9, 10. In this embodiment, a spark plug 15 is provided at a portion surrounded by a total of four intake / exhaust valves 9 and 10 per cylinder.

The intake port 7 is connected to an intake manifold 21 according to the present invention, so that intake air is supplied from the intake manifold 21. As shown in FIGS. 1 to 3, the intake manifold 21 includes a downstream manifold 22 attached to the cylinder head 5 and an upstream manifold 23 attached to the upstream end of the downstream manifold 22.
And an injector 24 for injecting fuel to the intake port 7 is attached. The material forming the downstream manifold 22 and the upstream manifold 23 is an aluminum alloy in this embodiment. Note that these two manifolds 22 and 23 may be formed of a synthetic resin.

The downstream manifold 22 includes two pipes 25 forming an intake passage for each cylinder,
5 and both pipes 2
5 and 25, and each pipe 2
5 is formed integrally with a downstream flange 27 for connecting the downstream end of the cylinder head 5 to the cylinder head 5. Each pipe 25 is formed linearly from the cylinder head 5 toward the upstream side of the intake so that the center line of the intake passage coincides with the intake port 7, and the intake passage is directed toward the side of the cylinder head 5 in the middle. It is formed to be curved so as to extend.

As shown in FIG. 3, the downstream flange 27 formed at the downstream end of each pipe 25 has a mounting seat 28 for fitting and holding one end 24a of the injector 24 on the fuel injection port side. 1 and 3, and is attached to the cylinder head 5 via a seal member 29. The mounting seat 28 is formed by a concave portion having a circular opening, and as shown in FIGS.
A structure is adopted in which the injector 24 is fitted and held via the. A through hole 31 for injecting fuel into the intake port 7 is formed in the bottom of the mounting seat 28.

The upstream manifold 23 includes a downstream flange 32 attached to the upstream flange 26 of the downstream manifold 22, two pipes 33 for guiding intake air to each pipe 25 of the downstream manifold 22, and these pipes 33. 33, surge tank 3 for guiding intake air to the upstream end of 33
4 are integrally formed. The downstream flange 32
Has a shape corresponding to the upstream flange 26 of the downstream manifold 22, and is formed so as to be bridged between the two pipes 33, 33 of the upstream manifold 23 to hold both pipes. The upstream flange 26 of the downstream manifold 22 has these two flanges 26,
It is attached by a fixing bolt 35 and a nut 36 that penetrate through 32. As shown in FIG. 3, a seal member 32a is interposed between these flanges 26 and 32 so that air is not sucked through a gap between the flanges 26 and 32. In this embodiment, an O-ring is used as the seal member 32a. This O-ring is connected to the upstream flange 26 of the downstream manifold 22.
Have been supported.

Each pipe 3 of the upstream manifold 23
3 is formed so that the upstream end is located above the downstream end in FIGS. 1 and 3, and the upstream end forms a part of the side wall and the upper wall of the surge tank 34. are doing. More specifically, each pipe 33 has a laterally extending portion 33a extending to the side of the cylinder head 5 along an extension of each of the pipes 25 of the downstream manifold 22, and an upstream end of the laterally extending portion 33a. It is formed by a vertically extending portion 33b extending upward and an intake inlet portion 33c extending in an inverted U-shape from the upper end of the vertically extending portion 33b.
As shown in FIG. 2, the intake port 33c has two pipes 3 toward the upstream side (right side in FIG. 2).
It is formed so that the interval between 3,33 gradually increases. An intake inlet pipe 37 of the surge tank 34 is provided between these intake inlet portions 33c.

The surge tank 34 is provided with the intake inlet pipe 37.
In addition, the intake port 33c of the two pipes 33, 33 is formed as a part of the upper wall, and the vertically extending part 33b of the two pipes 33, 33 is formed in a box shape as a part of the side wall,
An intake device 43 including a throttle valve 41 (see FIG. 1) and an air cleaner 42 is attached to the intake inlet pipe 37. As is well known, the throttle valve 41 has a built-in valve body 41a formed of a butterfly valve, and a throttle valve mounting seat 37a formed at the upstream end of the intake inlet pipe 37 (see FIG. 3). ), The downstream end is fixed, and the air cleaner 42 is attached to the upstream end.
The air inlet of the air cleaner 42 is designated by reference numeral 42a in FIG.
Indicated by

As shown in FIG. 1, the air suction device 43 is supported by a bracket 42b provided at an upstream end of the air cleaner 42.
a and the throttle valve 41 is attached to the intake pipe 37. The upstream manifold 23 is supported by the cylinder head 5 via the downstream manifold 22, and is supported by the cylinder body 2 via a support bracket 44 attached to the outer wall of the surge tank 34.

By adopting this support structure, the left end of the upstream manifold 23 in FIGS. 1 and 3 is supported on the left side of the cylinder body 2 via the support bracket 44, and the right end is Can be supported at the opposite end of the head cover 6 via the intake device 43, so that the upstream manifold 23 can be supported at two sides of the engine 1.

The fuel is distributed to the injector 24 between the side wall 34a (see FIG. 3) of the surge tank 34 facing the cylinder head 5 and the downstream flange 32 of the two pipes 33, 33 of the upstream manifold 23. Are integrally formed. Fuel rail 45
Is constituted by a fuel pipe 46 extending along the direction in which the cylinders are arranged as shown in FIG. 2, and bosses 47 for mounting injectors projecting from both ends of the fuel pipe 46 as shown in FIGS. The boss 47 connects the support piece 48 located on the opposite side of the fuel pipe 46 to the surge tank 34 of the upstream manifold 23 and the downstream flange 32.

As shown in FIG. 2, the fuel pipe 46 is provided at its upper end with a hose joint 46a for connecting a fuel supply hose (not shown). The fuel is fed to the fuel passage 49 under pressure. The boss 47 has a holding hole 50 having a circular opening shape, and is provided with the downstream manifold 2.
A structure is adopted in which the fuel inlet side end 24b of the injector 24 having the other end held at 2 is fitted and held in the holding hole 50. In this embodiment, the holding holes 50
Are formed so as to open into the fuel passage 49 so that the fuel is fed from the fuel passage 49 to the holding hole 50 by pressure. The fuel inlet side end 24b of the injector 24 has a fuel inlet (not shown) opened at the tip end surface, and a holding hole 50b.
An O-ring 51 is attached to the outer peripheral portion in order to prevent fuel from leaking from between the hole wall surfaces.

In order to assemble and attach the intake manifold 21 configured as described above to the cylinder head 5,
First, the upstream manifold 2 is connected to the downstream manifold 22.
Assemble 3. At this time, the downstream manifold 22
The fuel injection port side end 24a of the injector 24 is fitted and held in the mounting seat 28 for the injector via a seal member 30, and the fuel inlet of the injector 24 is inserted into the holding hole 50 of the fuel rail 45 of the upstream manifold 23. The side end 24b is fitted and held.

Then, in this state, the downstream manifold 2
The downstream flange 32 of the upstream manifold 23 is connected to the second upstream flange 26 by a fixing bolt 35 and a nut 36. Before the connection between the flanges 26 and 32 is performed, a seal member 32a is mounted on the upstream flange 26 in advance. After the two flanges are connected to each other, the downstream flange 27 of the downstream manifold 22 is attached to the cylinder head 5 via the seal member 29. This downstream flange 27 is attached
This is performed by inserting a stud bolt (not shown) erected on the cylinder head 5 into a bolt hole (not shown) of the downstream flange 27 and tightening a nut. afterwards,
The outer portion of the surge tank 34 is supported on the cylinder body 2 by the support bracket 44, and an intake device 43 is attached to the surge tank 34, and the air cleaner 42 of the intake device 43 is supported on the head cover 6.

Therefore, in the intake manifold 21 configured as described above, the fuel injection port end 24a of the injector 24 is fitted to the mounting seat 28 of the downstream manifold 22, and the fuel inlet side end of the injector 24 is fitted. 24b is connected to the holding hole 50 of the upstream manifold 23.
By connecting the two manifolds 22 and 23 with each other in a state where they are fitted to each other, the connection between the injector 24 and the fuel rail 45 and the fixing of the injector 24 can be performed at the same time.

The portion where the downstream manifold 22 and the upstream manifold 23 are connected to each other employs a simple fastening structure in which the flanges 26 and 32 provided at the ends of the manifold are fastened by fixing bolts 35 and nuts 36. Therefore, the assembling is easy even though the intake manifold 21 is divided into two. In addition, since a connection portion between the downstream manifold 22 and the upstream manifold 23 having the fuel rail 45 is provided in the middle of a heat transfer path between the engine 1 and the upstream manifold 23, the connection between the engine 1 and the upstream manifold 23 is provided. Thermal resistance can be increased.

In the above embodiment, the fuel rail 45
The fuel rail 45 is formed separately from the upstream manifold 23, and is formed integrally with the upstream manifold 23 by bolts or the like.
3 can also be attached. By forming the fuel rail 45 integrally with the upstream manifold 23, the number of assembly steps and the number of parts can be reduced as compared with a structure formed separately from the upstream manifold 23, and the assemblability is further improved. Can be done.

[0030]

As described above, according to the present invention, the connection between the injector and the fuel rail and the fixing of the injector can be performed at the same time, and the downstream manifold and the upstream manifold are connected to each other. Since it is possible to adopt a simple fastening structure in which flanges provided at the ends of the manifold are fastened with bolts and nuts, it is possible to improve the assemblability of the intake manifold provided with the injector. Also, the thermal resistance increases due to the connection between the upstream manifold and the downstream manifold,
While the fuel rail is formed integrally with the upstream manifold to reduce the number of parts, it is possible to reduce the transfer of heat of the engine to the fuel in the fuel rail.

According to the second aspect of the present invention, the support of the upstream manifold is stabilized, and the upstream manifold can be prevented from being displaced by the vibration of the engine with respect to the downstream manifold. A simple and simple seal structure can be employed for the part, and the assemblability can be further improved.

According to the third aspect of the present invention, the number of assembling steps and the number of parts can be reduced as compared with the case where the fuel rail is formed separately from the upstream manifold, so that the assemblability is further improved. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view of a fuel injection engine according to the present invention.

FIG. 2 is a plan view of a fuel injection engine according to the present invention.

FIG. 3 is a sectional view taken along line III-III of the intake manifold in FIG. 2;

FIG. 4 is an enlarged sectional view showing an injector mounting portion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 5 ... Cylinder head, 6 ... Head cover, 21 ... Intake manifold, 22 ... Downstream manifold, 23 ... Upstream manifold, 24 ... Injector
24a: fuel injection port side end; 24b: fuel inlet side end;
28 mounting seat, 34 surge tank, 41 throttle valve, 43 intake device, 44 support bracket, 45
Fuel rail, 46: fuel pipe, 47: boss, 49: fuel passage, 50: holding hole.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 53/00 F02M 55/02 340F 55/02 330 350H 340 35/10 102P 350 102B 301P

Claims (3)

[Claims] 1. A fuel injection engine in which an injector is mounted on an intake manifold, a downstream manifold having a mounting seat for fitting and holding one end of the injector on a fuel injection port side, and an upstream of the downstream manifold. The intake manifold is formed by an upstream manifold attached to an end, and the upstream manifold is formed by:
A fuel rail to which fuel is supplied is integrally provided, and a holding hole for fitting and holding the other end of the injector on the fuel inlet side is formed, and a fuel passage is formed in the holding hole from a fuel passage in the fuel rail. A fuel injection engine characterized by having a structure in which pressure is fed. 2. A fuel injection engine according to claim 1, wherein a surge tank and a seat for attaching a throttle valve are formed integrally with the upstream manifold, and the upstream manifold is provided on one side where an intake system of the engine is located. A fuel injection engine characterized in that an intake device having a throttle valve attached to an upstream manifold is supported on another side of the engine while being supported by a bracket via a bracket. 3. The fuel injection engine according to claim 1, wherein the fuel rail is formed integrally with the upstream manifold.