JPH11294288A - Engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an inspection without removing a cam case and to improve maintainability by independently installing the cam case supporting a cam shaft on a cylinder block on the side of a cylinder head fitted with a unit injector or intake/exhaust valves. SOLUTION: An engine main body E is constituted of a cylinder block 1, cylinder heads 2 and a cam case 3 adjacently arranged on the cylinder block 1, a rocker case 4 and a rocker cover 5 covering the upper face of the rocker case 4. The cam case 3 is integrally formed for multiple cylinders, and the cam case 3 is fastened to the upper face of the cylinder block l by the prescribed fastening means via a gasket in parallel with the cylinder heads 2. The cam case 3 is protruded from the upper face of the cylinder heads 2 by the prescribed height to open the upper face of an inner chamber 3a. Inspection can be made without removing the cam case 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine for an automobile or an industrial machine, and more particularly to an engine structure most suitable for a large engine having a high camshaft type unit injector driving system or a valve operating system.

[0002]

2. Description of the Related Art Conventionally, as a large diesel engine,
For example, an overhead valve (OH
There is a multi-cylinder (for example, six-cylinder) engine provided with a V) type unit injector drive system.

According to this, an engine body E is provided with a cylinder block 10 having an oil pan (not shown) mounted on a lower surface thereof.
0, a cylinder head 101, a rocker case 102, and a rocker cover 103.

[0004] A cylinder block 100 has a piston 106 in a cylinder bore 104 through a cylinder liner 105.
The camshafts 107 are rotatably supported by cam journals provided at the side of the cylinder row. Also, the cam of this cam shaft 107
A follower (or tappet) 108 driven by 107a is supported by a number corresponding to the number of cylinders so as to be freely swingable.

[0005] The cylinder head 101 is formed independently for each cylinder and is fastened to the upper surface of the cylinder block 100 with a tightening bolt 109, and a unit injector 110 is mounted vertically through the inside thereof.

In the rocker case 102 and the rocker cover 103, a rocker shaft 111 is axially supported in the cylinder row direction. One end of the rocker shaft 111 is provided on the unit injector 110 and the other end is provided with a push rod 112 on the rocker shaft 111. And the rocker arms 11 connected to the follower 108 via
3 is swingably supported.

Accordingly, by the rotation of the camshaft 107 interlocked with the crankshaft (not shown) via the gear train, the driving force is transmitted to the rocker arm 113 via the follower 108 and the push rod 112, and is transmitted from the unit injector 110 in each cylinder to the predetermined position. The fuel is injected at the timing of.

[0008]

However, a conventional multi-cylinder diesel engine having an overhead valve type unit injector drive system (or valve train system) requires a follower 108 and a push rod 112. Therefore, since the reciprocating mass of the inertia mass is large and the rigidity of the components is low, there has been a limit to increase the speed and the output (increase the size) of the engine.

That is, the follower 108 and the push rod 11
With the increase in size of 2 etc. and operation at high speed, the inertial mass reciprocating further increases and the rigidity of the components also decreases, the jumping phenomenon of the push rod 112 occurs, and the injection pressure and injection timing are incorrect. Engine performance will be reduced.

As a countermeasure, as shown in FIG. 3, an engine structure having an overhead camshaft (OHC) type unit injector drive system (or valve train), which is common in gasoline engines for passenger cars, is used. It is conceivable to adopt it for a multi-cylinder diesel engine or the like.

This is because the camshaft 107 and the rocker shaft 111 are mounted together with the rocker case 102 on the cylinder head 101.
And the rocker arm 113 is directly
The unit injector 110 is driven by following the cam 107a.

According to this, the follower 108 shown in FIG.
In addition, since the push rod 112 is not required, the inertial mass reciprocating is reduced, and the rigidity of the components is improved, so that the engine can be operated at a higher speed and a higher output (larger size) can be achieved.

However, since it is necessary to ensure the coaxiality of each cam journal portion in the rocker case 102 supporting the camshaft 107 and the like, the rocker case 102
However, there is a problem that productivity and maintenance are reduced due to the need to integrally form multiple cylinders.

That is, in terms of productivity, there are drawbacks in that the number of manufacturing steps and costs are increased, and in terms of maintainability, even if only one cylinder is inspected (replacement of the piston 106, etc.), every time. A multi-cylinder portion is formed integrally and a heavy object (for example, 10
It is necessary to remove the rocker case 102 (0 kg or more) using an overhead crane or the like, which is very troublesome. Incidentally, since the cylinder head 101 is formed independently for each cylinder and weighs about 30 kg, it can be easily removed by manual operation.

An object of the present invention is to provide an engine which achieves high speed and high output (large size) and which is excellent in productivity and maintainability.

[0016]

According to a first aspect of the present invention, there is provided an engine having a high camshaft type unit injector drive system or a valve operating system, wherein the unit injector or the intake and exhaust valves are provided. A cam case for supporting the cam shaft is independently installed on a cylinder block on the side of the attached cylinder head.

Further, the cam case is formed as a multi-cylinder integrated type.

Further, the cam case protrudes from the upper surface of the cylinder head by a predetermined height.

Further, in the cam case, an intake passage or an exhaust passage connected to an intake port or an exhaust port formed in the cylinder head is integrally formed.

Further, the cylinder head is formed independently for each cylinder.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an engine according to the present invention will be described in detail using embodiments with reference to the drawings.

First Embodiment [Configuration] FIG. 1 is a front sectional view of a main part of a multi-cylinder diesel engine showing a first embodiment of the present invention.

As shown in FIG. 1, an engine body E includes a cylinder block 1 having an oil pan (not shown) mounted on a lower surface thereof, a cylinder head 2 and a cam case 3 disposed adjacent to each other on the cylinder block 1. And a rocker case 4 provided over the upper surfaces of the cylinder head 2 and the cam case 3, and a rocker cover 5 covering the upper surface of the rocker case 4.

In the cylinder block 1, a piston 8 is housed in each cylinder bore 6 via a cylinder liner 7 so as to be slidable up and down, and an intake passage 9 is located at a side of each cylinder bore 6 so that an intake passage 9 is formed. It is formed. In the intake passage 9, an air cooler 10 is interposed, and fresh air is supplied to each cylinder through each opening 11 formed on the upper surface of the block.

The cylinder head 2 is formed independently for each cylinder, and is fastened to the upper surface of the cylinder block 1 by a fastening bolt 12 via a gasket (not shown).
A unit injector 13 is mounted inside the cylinder head 2 so as to penetrate vertically, and an intake port 14, an exhaust port (not shown), and a water jacket 1 are provided.
5 are formed by opening one end to the side of the head. In the figure, 25 is a copper tube for separating the water jacket 15 and the unit injector 13, 26 is an O-ring for water sealing, and 27 is a copper gasket for gas sealing.

The cam case 3 is formed integrally with a plurality of cylinders and is fastened to the upper surface of the cylinder block 1 by a predetermined fastening means via a gasket (not shown) alongside the cylinder heads 2. The cam case 3 is formed so as to protrude from the upper surface of the cylinder head 2 by a predetermined height, and the upper surface of the internal chamber 3a is opened. A cam shaft 16 is rotatably supported in the internal chamber 3a via cam journals provided in an appropriate number in the cylinder row direction. In the lower half of the cam case 3, an intake passage 17 having one end connected to the opening 11 and the other end connected to the intake port 14 is formed integrally with each cylinder.

The rocker case 4 is formed independently for each cylinder, and the lower surface is stepped so that it is strung over the upper surface of the cylinder head 2 and the upper surface of the cam case 3 with fastening bolts 18 respectively. Will be concluded. A rocker shaft 20 is axially supported by the rocker case 4 in the cylinder row direction. One end of the rocker shaft 20 is provided on the unit injector 13, and the other end is provided with an opening 4 a on the lower surface of the case (inside of the cam case 3). The rocker arms 21 connected to the cams 16a of the camshaft 16 are swingably supported through the chamber 16a).

The rocker cover 5 is formed integrally with a plurality of cylinders, and is fastened to the upper surface of the rocker case 4 by tightening bolts 19. In the drawings, reference numerals 22a and 22b are sealing members.

[Operation / Effect] With such a configuration, the driving force is transmitted to the rocker arm 21 by the rotation of the camshaft 16 linked to the crankshaft (not shown) via a gear train, and the unit injector 13 in each cylinder is provided. At a predetermined timing.

In this embodiment, the high camshaft type (the rocker arm 21 is directly connected to the cam 1 of the camshaft 16)
The engine structure has a unit injector drive system of an overhead camshaft type because it is common in that it is driven by the engine 6a. 4), the need for a follower (tappet) and a push rod is eliminated, the inertial mass reciprocating is reduced, and the rigidity of the components is improved. Can be planned.

Further, the cam case 3 integrally formed with multiple cylinders is independently installed on the cylinder block 1 on the side of the cylinder head 2 formed independently for each cylinder. At the time of inspection, such as removal and replacement of the piston 8, it is not necessary to remove the cam case 3, which is a heavy object, and the lightweight cylinder head 2, rocker case 4, rocker cover 5, and the like can be removed manually, thus improving maintainability. improves.

Further, since the cam case 3 is formed as a multi-cylinder integrated type, there is an advantage that the coaxiality can be easily secured and the engine performance can be improved.

Since the cam case 3 protrudes from the upper surface of the cylinder head 2 by a predetermined height, lubricating oil for camshaft lubrication scattered in the internal chamber 3a of the cam case 3 leaks to the upper surface side of the cylinder head 2. Without
There is an advantage that wasteful consumption of lubricating oil can be reduced.

In the cam case 3, an intake passage 17 or an exhaust passage connected to an intake port 14 or an exhaust port 15 formed in the cylinder head 2 is integrally formed, so that the space in the cam case 3 can be effectively used. Therefore, there is an advantage that the cylinder head 2 can be reduced in size and the protrusion to the side of the engine can be minimized.

Further, the mounting height of the rocker shaft 20 can be reduced by the amount that the camshaft 16 is arranged on the side of the cylinder head 2, thereby reducing the overall height of the engine, improving the mountability and reducing the weight. There is an advantage that can be achieved.

Further, since the cylinder head 2 is formed independently for each cylinder, it is excellent in maintainability and has an advantage that it is optimal for a large diesel engine.

Further, despite the fact that the cam case 3 is independently installed on the cylinder block 1 on the side of the cylinder head 2, the upper surface processing of the cylinder block 1 is one surface,
There is an advantage that there is no step processing, productivity is improved, and cost increase is small.

[Second Embodiment] [Structure] FIG. 1 is a front sectional view of a main part of a multi-cylinder diesel engine showing a second embodiment of the present invention.

This is an example in which the present invention is applied to a multi-cylinder diesel engine having a high camshaft type valve train. That is, in a multi-cylinder diesel engine in which the intake valve 30 and the exhaust valve (not shown) are opened and closed by the rocker arm 21 directly driven by the cam 16a of the camshaft 16, the cylinder block 1 on the side of the cylinder head 2 to which the intake and exhaust valves are attached. This is an example in which the cam case 3 supporting the camshaft 16 is installed independently as in the first embodiment.

According to this, the same operation as in the first embodiment can be obtained.
The effect is obtained.

In each of the above embodiments, an example in which the present invention is applied to a diesel engine has been described, but the present invention can also be applied to a gasoline engine.

[0042]

According to the first aspect of the present invention, in an engine having a high camshaft type unit injector drive system or a valve operating system, the cylinder on the side of the cylinder head to which the unit injector or the intake and exhaust valves are attached. Since the cam case supporting the camshaft is independently installed on the block, the reciprocating inertial mass is reduced, and the rigidity of the components is improved.
The engine speed can be increased and the output can be increased (increased in size). In addition, inspection such as piston replacement can be performed without removing the cam case, thereby improving maintainability.

According to the second aspect of the present invention, the cam case is
Since it is formed as a multi-cylinder integrated type, coaxiality can be easily ensured and engine performance can be improved.

According to the third aspect of the present invention, the cam case is
Since it protrudes from the cylinder head upper surface by a predetermined height,
Lubricating oil for camshaft lubrication scattered in the interior chamber of the cam case does not leak to the upper surface side of the cylinder head, and wasteful consumption of lubricating oil can be reduced.

According to the fourth aspect of the present invention, the cam case is
Since the intake passage or the exhaust passage connected to the intake port or the exhaust port formed in the cylinder head is integrally formed, the space in the cam case can be effectively used,
The cylinder head can be miniaturized and the protrusion to the side of the engine can be minimized.

According to the fifth aspect of the present invention, since the cylinder head is formed independently for each cylinder, it is excellent in maintainability and is most suitable for a large engine.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a main part of a multi-cylinder diesel engine showing a first embodiment of the present invention.

FIG. 2 is a front sectional view of a main part of a multi-cylinder diesel engine showing a second embodiment of the present invention.

FIG. 3 is a front sectional view of a main part of a multi-cylinder engine including an overhead camshaft (OHC) type unit injector drive system.

FIG. 4 is a front sectional view of a main part of a conventional multi-cylinder engine equipped with an overhead valve (OHV) type unit injector drive system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder head 3 Cam case 4 Rocker case 5 Rocker cover 13 Unit injector 16 Camshaft 17 Intake passage

Claims (5)

[Claims] 1. An engine equipped with a high camshaft type unit injector drive system or a valve operating system, wherein said camshaft is supported on a cylinder block on a side of a cylinder head to which said unit injector or intake and exhaust valves are attached. The engine is characterized by an independent cam case. 2. The engine according to claim 1, wherein the cam case is formed as a multi-cylinder integrated type. 3. The cam case according to claim 1, wherein the cam case protrudes from the upper surface of the cylinder head by a predetermined height.
Or the engine according to 2. 4. The engine according to claim 1, wherein the cam case is formed integrally with an intake passage or an exhaust passage connected to an intake port or an exhaust port formed in a cylinder head. . 5. The engine according to claim 1, wherein the cylinder head is formed independently for each cylinder.