JPH0643261U - Fuel passage structure of internal combustion engine - Google Patents

Abstract

(57) [Summary] [Structure] The fuel injection valve 2 attached to the cylinder head 1 is covered with a valve arm chamber cover 3. That valve arm chamber cover 3
To the connecting member 30 which is inserted into the fuel injection valve 2 from the outside and is connected to the connecting member 30 outside the fuel inlet 16 of the fuel injection valve 2 and the valve arm chamber cover 3. A fuel flow path 35 communicating with 31 is formed. [Effect] Combustion efficiency can be improved without requiring work for connecting the fuel supply pipe inside the valve arm chamber cover, and without forming a fuel passage within the wall thickness of the cylinder head. A passage structure can be provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fuel passage structure for an internal combustion engine.

[0002]

[Prior art]

 The diesel engine shown in FIG. 5 includes a cylinder head 101, a fuel injection valve 102 attached to the cylinder head 101, and a valve arm chamber cover 103 that covers the cylinder head 101. The fuel injection valve 102 has a central axis O ′ inclined by 10 ° or more with respect to the bottom surface of the cylinder head 101 and arranged outside the valve arm chamber cover 103. A fuel supply pipe 104 is connected to a fuel inlet located on one side of the fuel injection valve 102. The connection position between the fuel inlet and the fuel supply pipe 104 is outside the valve arm chamber cover 103. The fuel injection valve 102 is prevented from coming off from the cylinder head 101 by being pressed by a metal fitting 106 bolted to the cylinder head 101.

[0003]

[Problems to be solved by the device]

 As shown in FIG. 6, the fuel injection directions from the plurality of fuel injection holes 102a formed in the fuel injection valve 102 are different from each other with respect to the central axis O '. This is because when the central axis O ′ of the fuel injection valve 102 is inclined with respect to the bottom surface of the cylinder head 101 as described above, the angle θ formed by the fuel injection direction from each fuel injection hole 102a and the bottom surface of the cylinder head 101 is θ. Is to be equal to each other.

However, if the fuel injection directions from the plurality of fuel injection holes 102a are greatly different from each other with respect to the central axis O ', the fuel flow up to the fuel injection becomes non-uniform, so that the injection amount of each fuel spray is increased. Becomes non-uniform, and the properties of the fuel spray fluctuate, resulting in non-uniform mixing of fuel and air, increasing the amount of fuel particles in the exhaust gas and reducing combustion efficiency.

Therefore, it is conceivable to make the central axis of the fuel injection valve orthogonal to the bottom surface of the cylinder head or to make the inclination angle small. However, when this is done, the fuel injection valve is covered by the valve arm chamber cover, The fuel inlet is located inside the valve arm chamber cover. However, since the space inside the valve arm chamber cover is limited, it is difficult to connect the fuel supply pipe with a large bending rigidity and a small degree of freedom of arrangement to the fuel inlet, and the connection work is difficult. Therefore, it was necessary to divide the valve arm chamber cover into two, which increased the number of parts.

Therefore, when the fuel injection valve is covered with the valve arm chamber cover, in order to eliminate the piping inside the valve arm chamber cover, the fuel flow path communicating with the fuel inlet of the fuel injection valve is formed within the thickness of the cylinder head. Is being formed. However, when the cylinder head is small, as in a small-sized engine having a two-valve system and a small cylinder diameter, there is no room to form such a fuel flow path within the wall thickness of the cylinder head.

An object of the present invention is to provide a fuel passage structure of an internal combustion engine that can solve the above-mentioned problems of the conventional art.

[0008]

[Means for Solving the Problems]

 The first aspect of the present invention is characterized in that in an internal combustion engine including a cylinder head, a fuel injection valve attached to the cylinder head, and a valve arm chamber cover that covers the cylinder head, the fuel injection valve is a valve. A connecting member is provided that is covered by the arm chamber cover, is inserted into the valve arm chamber cover from the outside, and is screwed into the fuel injection valve.The connecting member includes a fuel inlet of the fuel injection valve and a valve arm chamber. The point is that a fuel flow path is formed outside the cover to communicate with the fuel supply pipe connected to the connecting member.

A feature of the second aspect of the present invention resides in an internal combustion engine including a cylinder head, a fuel injection valve attached to the cylinder head, and a valve arm chamber cover that covers the cylinder head. The valve is covered with a valve arm chamber cover, and a cylindrical connecting member that is inserted into the valve arm chamber cover from the outside and is screwed into the fuel injection valve is provided, and the fuel supply pipe is inserted into the connecting member. The connecting member has a pressing portion that presses the tip of the fuel supply pipe against the periphery of the fuel inlet of the fuel injection valve when the connecting member is screwed into the fuel injection valve.

A feature of the third aspect of the present invention resides in an internal combustion engine including a cylinder head, a fuel injection valve attached to the cylinder head, and a valve arm chamber cover that covers the cylinder head. The valve is located inside the cylinder head, and a cylindrical connecting member that is inserted into the valve arm chamber cover from the outside and is screwed into the cylinder head is provided, and the fuel supply pipe is inserted into the connecting member. The connecting member has a pressing portion for pressing the tip of the fuel supply pipe against the periphery of the fuel inlet of the fuel injection valve when the connecting member is screwed into the cylinder head.

[0011]

[Action]

 According to the configurations of the respective inventions, since the central axis of the fuel injection valve can be made small at a right angle or an inclination angle with respect to the bottom surface of the cylinder head, the positions of the plurality of fuel injection holes formed in the fuel injection valve can be reduced. The position where the fuel injection directions are substantially equal to the central axis can be set. As a result, the injection amount for each fuel spray is made uniform, the properties of the fuel spray are made uniform, and the mixture of fuel and air is made uniform, so the amount of fuel particles in the exhaust gas is reduced and combustion efficiency is improved. To do.

According to the first and second aspects of the present invention, the fuel inlet of the fuel injection valve and the fuel supply pipe can be formed by simply inserting the connecting member into the valve arm chamber cover from the outside and screwing the screw into the fuel injection valve. Are connected. That is, by simply inserting the connecting member into the valve arm chamber cover and screwing it into the fuel injection valve, the fuel passage inside the valve arm chamber cover with respect to the fuel inlet of the fuel injection valve can be configured. There is no need to connect the pipes inside.

Further, according to the second aspect of the present invention, the tip of the fuel supply pipe inserted in the tubular connecting member is screwed into the fuel injection valve by the pressing portion formed in the connecting member. Sometimes it can be pressed around the fuel inlet of the fuel injector. That is, since the fuel supply pipe can be directly connected to the fuel inlet of the fuel injection valve, there is no need for parts and labor for connecting the connecting member and the fuel supply pipe.

According to the third aspect of the present invention, the fuel inlet of the fuel injection valve and the fuel supply pipe are connected only by inserting the connecting member into the valve arm chamber cover from the outside and screwing it into the cylinder head. That is, the fuel passage inside the valve arm chamber cover with respect to the fuel inlet of the fuel injection valve can be configured by inserting the connecting member into the valve arm chamber cover and screwing it into the cylinder head. No need to connect In addition, the tip of the fuel supply pipe inserted into the tubular connecting member is attached to the periphery of the fuel inlet of the fuel injection valve when the connecting member is screwed into the cylinder head by the pressing portion formed on the connecting member. It can be pressed. That is, since the fuel supply pipe can be directly connected to the fuel inlet of the fuel injection valve, the parts and labor for connecting the connecting member and the fuel supply pipe are unnecessary. Further, since the connecting member presses the fuel injection valve by the pressing portion via the tip of the fuel supply pipe, there is no need for parts and labor for preventing the fuel injection valve from coming off from the cylinder head.

[0015]

【Example】

 An embodiment of the first invention of the present application will be described with reference to FIGS.

The multi-cylinder diesel engine shown in FIG. 1 has a cylinder head 1 attached to an upper portion of a cylinder block 8, a fuel injection valve 2 attached to the cylinder head 1 corresponding to each cylinder, A valve arm chamber cover 3 that covers the cylinder head 1 is provided. Inside the valve arm chamber cover 3, a valve arm 4 driven by an engine is arranged.

Each fuel injection valve 2 is inserted into the through hole 1 b of the cylinder head 1 and covered with the valve arm chamber cover 3 such that the central axis O is perpendicular to the bottom surface 1 a of the cylinder head 1. In order to prevent the fuel injection valve 2 from coming off from the cylinder head 1, an L-shaped coming-off preventing member 6 is attached to the cylinder head 1 with a bolt 10, and one end of the coming-off preventing member 6 is a forked portion 6a. The forked portion 6a presses the flange 2d protruding outward from the fuel injection valve 2. As a result, the fuel injection valve 2 is pressed against the step surface 1b ′ of the through hole 1b of the cylinder head 1 via the spacer 50.

Each fuel injection valve 2 has a nozzle 12 and a nozzle holder 15, a fuel inlet 16 is formed on the upper surface of the nozzle holder 15, and a fuel return port 17 is formed on the side surface of the nozzle 12. As shown in FIG. 2, a plurality of fuel injection holes 18 are formed at the tip of the. The positions of the fuel injection holes 18 are set so that the fuel injection directions become equal to each other with respect to the central axis O. The fuel inlet 16 and the fuel injection hole 18 communicate with each other through a passage 20, and the fuel return port 17 and the fuel injection hole 18 communicate with each other through a passage 21.

A connecting member 30 that is inserted into the valve arm chamber cover 3 from the outside and is connected to the fuel injection valve 2 is provided. The connecting member 30 has a stepped columnar shape and penetrates a through hole 3 a formed in the upper portion of the valve arm chamber cover 3. An internal thread 30a is formed on the lower end of the connecting member 30, an external thread 30b is formed on the upper end, and the internal thread 30a located inside the valve arm chamber cover 3 is formed on the nozzle holder 15 of the fuel injection valve 2. The tapered surface of the inner end of the connecting member 30 is screwed onto the male screw 15a, and is pressed against the upper end surface of the nozzle holder 15 which is the conical recess where the fuel inlet 16 opens. Further, a connector 32 for connecting the fuel supply pipe 31 and the connecting member 30 is screwed onto the male screw 30b at the upper end of the connecting member 30, and the connector 32 constitutes a tip portion of the fuel supplying pipe 31. The tapered surface of the tip of the metal fitting 33 is pressed against the end surface of the connecting member 30 which is a conical recess. A fuel flow path 35 that connects the fuel inlet 16 of the fuel injection valve 2 and the fuel supply pipe 31 is formed along the center of the connecting member 30. An O-ring 45 is interposed between the outer peripheral surface of the connecting member 30 and the through hole 3a.

Further, one end of a T-shaped pipe 45 is connected to the fuel recirculation port 17 formed on one side of each fuel injection valve 2, and the respective pipes 45 are connected to each other by a hose (not shown). It communicates with the fuel tank via a pipe (not shown), and thus a fuel return path is formed.

According to the above configuration, since the central axis O of the fuel injection valve 2 is perpendicular to the bottom surface 1a of the cylinder head 1, the positions of the plurality of fuel injection holes 18 of the fuel injection valve 2 are set at the same position as the fuel. The injection directions can be set to be equal to each other with respect to the central axis O. As a result, the injection amount for each fuel spray is made uniform, the properties of the fuel spray are made uniform, and the mixture of fuel and air is made uniform, so the amount of fuel particles in the exhaust gas is reduced and combustion efficiency is improved. Will improve.

Further, the connecting member 30 is inserted into the valve arm chamber cover 3 from the outer side, and is screwed into the fuel injection valve 2 to be connected, whereby the fuel inlet 16 of the fuel injection valve 2 and the fuel supply pipe 31. And are connected via a fuel flow path 35 formed in the connecting member 30. That is, the fuel passage inside the valve arm chamber cover 3 with respect to the fuel inlet 16 of the fuel injection valve 2 can be configured only by inserting the connecting member 30 into the valve arm chamber cover 3 and connecting it to the fuel injection valve 2. The operation of connecting the fuel pipe inside the valve arm chamber cover 3 is not required.

FIG. 3 shows an embodiment of the second invention of the present application. The same parts as those of the first invention of the present application are designated by the same reference numerals, and different points will be described.

That is, the connecting member 30 has a stepped cylindrical shape, and the fuel supply pipe 31 is inserted therein. A female screw 30a is formed on the inner circumference of the lower end of the connecting member 30, and a pressing portion 30c is formed on the upper inner circumference of the female screw 30a. The pressing portion 30c has a tip end of a connecting fitting 33 that forms a front end portion of the fuel supply pipe 31 when the female screw 30a is screwed into the male screw 15a formed on the upper portion of the nozzle holder 15 of the fuel injection valve 2. The tapered surface of No. 1 is pressed against the upper end surface of the nozzle holder 15 in which the fuel inlet 16 is opened, which is a conical recess. Others have the same configuration as the embodiment of the first invention of the present case.

According to the second embodiment of the present invention, the same effects as those of the first embodiment of the present invention can be obtained, and further, the fuel supply pipe 31 as in the embodiment of the first invention is provided. The connector 32 for connecting with the connecting member 30 is not necessary, and the number of parts and the number of assembling steps can be reduced.

FIG. 3 shows an embodiment of the third invention of the present application. The same parts as those of the first embodiment of the present invention are designated by the same reference numerals, and different points will be described.

That is, the connecting member 30 has a stepped cylindrical shape, and the fuel supply pipe 31 is inserted therein. A male screw 30d is formed on the outer circumference of the lower end of the connecting member 30, and a pressing portion 30c is formed on the inner circumference of the lower end. Further, the fuel injection valve 2 is located inside the cylinder head 1 by being inserted into the through hole 1b formed in the cylinder head 1, and the male screw 15a as in the above embodiment is not formed at the upper end thereof. A female screw 1c is formed on the inner circumference of the upper end of the through hole 1b of the cylinder head 1, and a male screw 30d at the lower end of the connecting member 30 is screwed onto the female screw 1c. When the male screw 30d is screwed into the female screw 1c, the pressing portion 30c on the inner circumference of the connecting member 30 causes the taper surface of the tip of the connecting fitting 33, which constitutes the tip of the fuel supply pipe 31, to move to the fuel inlet. 16 is pressed against the upper end surface of the nozzle holder 15, which is a conical recessed portion. As a result, the fuel injection valve 2 is pressed against the step surface 1b ′ of the through hole 1b of the cylinder head 1 via the spacer 50.

Further, through holes 38 are formed in the wall thickness of the cylinder head 1 so as to correspond to the respective cylinders, and one end of each through hole 38 is connected to a fuel recirculation port formed on one side of the fuel injection valve 2. A through hole 39, which communicates with the other end of each through hole 38, is formed in the wall thickness of the cylinder head 1, and the through hole 39 communicates with a fuel tank through a pipe (not shown). As a result, the through holes 38, 39 formed in the wall thickness of the cylinder head 1 form a fuel return passage.

Further, the retaining member 6 as in the above embodiment is not provided. The other parts have the same structure as the embodiment of the first invention of the present invention.

According to the third embodiment of the present invention, the same effects as those of the first and second embodiments of the present invention can be obtained, and the connecting member 30 has the cylinder head 1 of the fuel injection valve 2. Since it has the function of preventing the slip-off, the slip-off preventing member 6 as in each of the above-described embodiments is unnecessary, and the number of parts and the number of assembling steps can be reduced.

The present invention is not limited to the above embodiments. For example, the axis of the fuel injection valve may be slightly inclined with respect to the bottom surface of the cylinder head.

[0032]

[Effect of device]

 According to the respective inventions, the combustion efficiency can be improved without requiring the work of connecting the fuel supply pipe inside the valve arm chamber cover and without forming the fuel passage in the wall thickness of the cylinder head. It is possible to provide a fuel passage structure suitable for a small engine, and according to the second and third inventions of the present case, it is possible to reduce the number of parts constituting the fuel passage structure and the number of assembling steps.

[Brief description of drawings]

FIG. 1 is a sectional view of an engine according to an embodiment of the present invention.

FIG. 2 is a partial sectional view of a fuel injection valve according to an embodiment of the present invention.

FIG. 3 is a sectional view of an engine according to an embodiment of the present invention.

FIG. 4 is a sectional view of an engine according to an embodiment of the third invention of the present case.

FIG. 5 is a sectional view of a conventional engine.

FIG. 6 is a partial sectional view of a conventional fuel injection valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Fuel injection valve 3 Valve arm chamber cover 16 Fuel inlet 30 Connecting member 30c Pressing portion 31 Fuel supply pipe 35 Fuel flow path

Claims (3)

[Scope of utility model registration request] 1. An internal combustion engine comprising a cylinder head, a fuel injection valve attached to the cylinder head, and a valve arm chamber cover covering the cylinder head, the fuel injection valve being covered by the valve arm chamber cover, A connecting member that is inserted into the valve arm chamber cover from the outside and is screwed into the fuel injection valve is provided, and the connecting member is connected to the fuel inlet of the fuel injection valve and the connecting member outside the valve arm chamber cover. A fuel passage structure for an internal combustion engine, characterized in that a fuel flow path communicating with the fuel supply pipe is formed. 2. An internal combustion engine comprising a cylinder head, a fuel injection valve attached to the cylinder head, and a valve arm chamber cover covering the cylinder head, the fuel injection valve being covered by the valve arm chamber cover, A tubular connecting member that is inserted into the valve arm chamber cover from the outside and screwed into the fuel injection valve is provided, and a fuel supply pipe is inserted into the connecting member, and the fuel of the connecting member is inserted into the connecting member. A fuel passage structure for an internal combustion engine, comprising a pressing portion for pressing a tip of a fuel supply pipe against a peripheral portion of a fuel inlet of the fuel injection valve when screwed into the injection valve. 3. An internal combustion engine comprising a cylinder head, a fuel injection valve attached to the cylinder head, and a valve arm chamber cover covering the cylinder head, the fuel injection valve being located inside the cylinder head. A cylindrical connecting member that is inserted into the valve arm chamber cover from the outside and is screwed into the cylinder head is provided, a fuel supply pipe is inserted into the connecting member, and the connecting member has a cylinder head of the connecting member. A fuel passage structure for an internal combustion engine, wherein a pressing portion for pressing the tip of the fuel supply pipe against the peripheral portion of the fuel inlet of the fuel injection valve when screwed into the fuel passage is formed.