JPH0368215B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a four-stroke internal combustion engine in which a crankshaft is arranged vertically along the vertical direction.

[Prior Art] For example, a four-stroke engine with a vertical crankshaft, which is used as a power source for an outboard motor, is attached to the upper end of a casing that extends in the vertical direction, and the engine is surrounded by a cover connected to the casing. Twisted and covered.

By the way, in this type of internal combustion engine, when the intake valve and exhaust valve are arranged in an overhead valve type, and the cylinder head is provided with a valve mechanism that opens and closes the intake valve and exhaust valve, A head cover to cover the valve mechanism and a spark plug will be installed. Since the spark plug is frequently maintained and inspected among the accessory parts of the internal combustion engine, it is desirable to arrange it in a position where it can be easily attached and detached.

[Problems to be Solved by the Invention] However, considering only the ease of attaching and removing the spark plug, it is preferable that the spark plug protrudes upward from the cylinder head. However, if you do this, the height of the engine will increase as the spark plug protrudes, and in order to avoid interference between the spark plug and the cover on the casing side, there will be a large space between the cover and the cylinder head. Inconveniences arise, such as having to secure space and increasing the size of the cover.

The present invention was developed based on these circumstances, and it is possible to reduce the height of the cylinder head including the spark plug, thereby making the cover smaller and creating a compact overall crankshaft with good ignitability. The purpose is to provide a stationary 4-stroke internal combustion engine.

[Means for Solving the Problems] Therefore, in the present invention, a cylinder block and a crankcase in which the cylinder is placed horizontally and the crankshaft is vertically placed along the vertical direction are supported by a base guide, while the cylinder An intake valve and an exhaust valve are arranged vertically in the head with respect to a center line passing through the center of the bore of the cylinder, and a head cover is fitted onto the cylinder head to cover the valve mechanism for driving the intake valve and the exhaust valve. , a four-stroke internal combustion engine in which the head cover, the cylinder head, and the upper part of the cylinder are covered with another cover, and an intake passage opened and closed by the intake valve and an exhaust passage opened and closed by the exhaust valve, The spark plugs are led out in opposite directions along the lateral direction intersecting the crankshaft, and the exhaust port is located below the intake port, and the spark plug is arranged above the exhaust passage that is opened and closed by the exhaust valve. It is characterized by the spark plug being led out in the lateral direction of the cylinder head.

[Operation] According to this configuration, the ignition plug passes through the dead space opened above the exhaust passage and is led out laterally to the side of the cylinder head, so it is directed upward to the cylinder head covered with another cover. Since the spark plug does not protrude, the height of the cylinder head including the spark plug can be kept low.

Further, the cover can be moved closer to the cylinder head and the head cover to the extent that the spark plug does not protrude, and the height of the cover can be lowered to make the entire engine more compact.

Furthermore, since the spark plug is disposed above the exhaust passage, the diameter of this exhaust passage is smaller than that of the intake passage, so that sufficient space can be secured above the exhaust passage.

Furthermore, the intake passage, which is opened and closed by the intake valve, and the exhaust passage, which is opened and closed by the exhaust valve, are led out in opposite directions along a lateral direction that intersects with the crankshaft, and the exhaust port is connected to the intake passage. By arranging the spark plug above the exhaust passage, which is located below the mouth and opened and closed by the exhaust valve, the vortex flow of fuel in the combustion chamber swirls from above to below, and is transmitted along the wall of the intake passage. The fuel flowing into the combustion chamber is easily stirred, and the combustion gas near the spark plug is smoothly discharged from the exhaust valve to the exhaust passage.

[Embodiment] An embodiment of the present invention will be described below based on drawings in which the present invention is applied to an outboard motor.

The casing of the outboard motor indicated by reference numeral 1 in the figure is composed of an atsupa casing 2 and a lower casing 3. On a base guide 4 that closes the upper end opening of the atsupa casing 2, a four-cycle internal combustion engine 5 is mounted. is installed. Inside the casing 1 is a drive shaft 6 that is rotationally driven by the internal combustion engine 5.
is inserted through the drive shaft 6, and the propeller 8 is inserted through the propeller shaft 7 at the lower end of the lower casing 3.
is driven in rotation.

Note that the reference numeral 9 in the figure is a cowling serving as another cover that covers the internal combustion engine 5 from above to the sides.

By the way, as shown in FIG. 3, the internal combustion engine 5 has a pair of cylinders 1 in a cylinder block 10.
These cylinders 11, 11 are placed horizontally so that their cylinder axes extend along the longitudinal direction of the outboard motor. Further, a crankcase 12 is attached to the front end surface of the cylinder block 10. Inside the crankcase 12,
A crankshaft 14 rotatably driven by the piston 13 is vertically supported vertically, and the drive shaft 6 is connected to the lower end of the crankshaft 14.
are connected.

A cylinder head 15 is connected to the rear end surface of the cylinder block 10, and an intake port 17 and an exhaust port 18 that are connected to the combustion chamber 16 of each cylinder 11 are opened in the cylinder head 15. These intake ports 17 and exhaust ports 18 are shown in FIGS.
As shown in the figure, they are arranged vertically with respect to a center line X1 passing through the center of the bore of the cylinder 11, and the large-diameter intake port 17 is located above. Inside the cylinder head 15, an intake passage 19 connected to the intake port 17 and an exhaust passage 20 connected to the exhaust port 18 are formed.
are derived in opposite directions to each other along the lateral direction intersecting the crankshaft 14. And intake passage 1
9 is opened on one side of the cylinder head 15,
An exhaust passage 20, which is connected to an intake device such as a carburetor (not shown) and has a smaller diameter than the intake passage 19, is bent toward the cylinder block 10 as shown in FIG. It is connected to an exhaust outlet passage 21 provided within the cylinder block 10.

The exhaust outlet path 21 is opened to an exhaust expansion chamber 23 inside the casing 1 through an exhaust pipe 22 extending downward from the base guide 4.

Further, the cylinder head 15 is provided with an intake valve 25 for opening and closing the intake port 17, and an exhaust valve 26 for opening and closing the exhaust port 18, and the valve arrangement is of an overhead valve type. A valve operating mechanism 29 that opens and closes the intake valve 25 and the exhaust valve 26 is provided on the rear end surface. The valve mechanism 29 of this embodiment consists of a single camshaft 30 placed vertically in the vertical direction, and a rocker arm 32 swingably supported on a rocker shaft 31. It is linked to the crankshaft 14 via a mechanism 33. A peripheral wall portion 15a that frames the outer periphery of the cylinder head 15 is erected rearward on the rear end surface of the cylinder head 15, and a head cover 27 that covers the valve mechanism 29 is provided on the rear end surface of the peripheral wall portion 15a. is bolted.

On the other hand, a plug hole 34 into which a spark plug 35 is screwed is opened in the rear end surface of the cylinder head 15. This plug hole 34 is opened into the combustion chamber 16 above the exhaust port 18 and the exhaust passage 20, and the bore center line It is tilted at a certain angle with respect to the Therefore, regarding the spark plug 35,
The insulator portion 35a passes through the peripheral wall portion 15a of the cylinder head 15 and is led out in the lateral direction of the cylinder head 15.

According to this configuration, the spark plug 35 passes through the dead space created above the exhaust passage 20 and is led out laterally to the side of the cylinder head 15, so that the spark plug 35 is extended above the cylinder head 15. Since it does not protrude, the height of the cylinder head 15 including the spark plug 35 can be kept low.

At the same time, since the spark plug 35 does not protrude upward, the upper surface of the cowling 9 can be brought closer to the cylinder head 15 and the head cover 27, and the height of the cowling 9 can be kept low to make the entire internal combustion engine 5 more compact. I can do it.

Furthermore, since the spark plug 35 is mounted above the exhaust passage 20, this exhaust passage 20 usually has a smaller diameter than the intake passage 19, so a sufficient space can be secured above the exhaust passage 20, and the spark plug 35 This has the advantage of making it more convenient to perform the work of attaching and detaching.

Note that the internal combustion engine according to the present invention is not limited to being used as an outboard motor, and can similarly be implemented as a power source for other general-purpose machines such as a lawn mower.

[Effects of the Invention] According to the present invention described in detail above, the cylinder block and crankcase, in which the cylinder is placed horizontally and the crankshaft is placed vertically along the vertical direction, are supported by the base guide, while the cylinder head In this method, an intake valve and an exhaust valve are arranged vertically with respect to a center line passing through the center of the bore of the cylinder, and a head cover is fitted onto the cylinder head to cover a valve mechanism for driving the intake valve and the exhaust valve.
Although the head cover, the cylinder head, and the upper part of the cylinder are covered with other covers to form a four-cycle internal combustion engine, the spark plug is included because the spark plug does not protrude significantly upwards of the cylinder head. The height of the cylinder head can be kept low. Furthermore, the upper surface of the cover can be placed closer to the cylinder head and the head cover, and the overall internal combustion engine can be made more compact.

Furthermore, the cylinder block and crankcase are reliably supported by the base guide, and the crankshaft is also reliably guided by the base guide.

Furthermore, since the spark plug is placed above the exhaust passage, this exhaust passage has a smaller diameter than the intake passage, so sufficient space can be secured above it, making it easier to install and remove the spark plug. can be done.

Furthermore, the intake passage opened and closed by the intake valve and the exhaust passage opened and closed by the exhaust valve are led out in opposite directions along a lateral direction intersecting the crankshaft, and the exhaust port is led out in opposite directions. By arranging the spark plug below the intake port and above the exhaust passage that is opened and closed by the exhaust valve, the vortex flow of fuel in the combustion chamber swirls from above to below, causing the walls of the intake passage to The fuel flowing into the combustion chamber is easily stirred, and the combustion gas near the spark plug is smoothly discharged from the exhaust valve to the exhaust passage, improving ignition performance.

[Brief explanation of drawings]

The drawings show one embodiment of the invention, and FIG.
2 is a front view of the cylinder head, 3 is a sectional view of the entire internal combustion engine,
FIG. 4 is a side view of the outboard motor. 4...Base guide, 5...Internal combustion engine, 9...
Cover (cowling), 14...Crankshaft, 1
5...Cylinder head, 17...Intake port, 18...
...Exhaust port, 19, 20...Passage (intake passage, exhaust passage), 25...Intake valve, 26...Exhaust valve, 27
...Head cover, 29...Valve mechanism, 35...
Spark plug, X1...Bore center line.

Claims (1)

[Claims] 1. A cylinder block and a crankcase in which the cylinder is placed horizontally and the crankshaft is placed vertically along the vertical direction are supported by a base guide, and the cylinder head is provided with an intake valve and an exhaust valve. are arranged vertically with respect to the center line passing through the center of the bore of the cylinder, and a head cover that covers the valve mechanism for driving the intake valve and exhaust valve is fitted onto the cylinder head, and the head cover, cylinder head, and cylinder are A four-stroke internal combustion engine whose upper part is covered with another cover, wherein an intake passage opened and closed by the intake valve and an exhaust passage opened and closed by the exhaust valve are arranged in a lateral direction intersecting with the crankshaft. The spark plug is led out in opposite directions along the cylinder head, and the exhaust port is located below the intake port, and the spark plug is placed above the exhaust passage that is opened and closed by the exhaust valve, and the spark plug is placed in the horizontal direction of the cylinder head. A four-stroke internal combustion engine with a vertical crankshaft.