Internal combustion engine

Abstract

The present invention reduces the size of an internal combustion engine and the like while securing a sufficient amount of lubricating oil for rocker shafts in the internal combustion engine. A cam holder formed in a cylinder head extends from a rear wall portion of the cylinder head toward the attachment hole, and an intake-side downstream rocker shaft oil supply passage formed in a cross shape by causing two linear portions to intersect each other is formed inside the cam holder. In the intake-side downstream rocker shaft oil supply passage, one of the linear portions communicates with a left intake-side support hole located on a left side and configured to support a left intake-side rocker shaft, while the other one of the linear portions communicates with a right intake-side support hole located on a right side and configured to support a right intake-side rocker shaft.

Description

technical field [0001] The present invention relates to internal combustion engines. Background technique [0002] Conventionally, an internal combustion engine of such a structure is known that an oil supply passage extending across a cylinder block and a cylinder head is branched into an oil supply passage communicating with a support portion of a rocker shaft in a wall portion of the cylinder head, and a support for a camshaft. An oil supply passage through which the parts are connected (refer to Patent Document 1). [0003] The internal combustion engine of Patent Document 1 is a diesel internal combustion engine, and the fuel injection valve is installed so as to communicate with the approximate center (most top) of the combustion chamber. In addition, the internal combustion engine is a 4-valve internal combustion engine, and multiple valves are arranged along the axial direction of the camshaft. intake and exhaust valves and intake and exhaust rocker arms. [0004] ...

AI Technical Summary

Problems solved by technology

[0005] In an internal combustion engine, there is a problem that since the shape of the cylinder head is complicated and many parts are installed in the cylinder head, the space for forming the oil supply passage is limited. The lubricating oil supply path of the camshaft, the oil supply path becomes complicated and the path length becomes longer, or, in order to ensure the formation space of the oil supply path, the wall of the cylinder head must be thickened, and it is difficult to take care of the lubricating oil. Quantity assurance and miniaturization, etc.

[0006] Specifically, when the fuel injection valve is mounted substantially in the center of the combustion chamber as in Patent Document 1, and a plurality of rocker arms and the like are arranged along the axial direction of the camshaft, the bearing portion of the camshaft, Four points, namely, the intake and exhaust rocker shaft support parts located on both sides of the bearing part in the axial direction of the camshaft, branch the oil supply path, and the oil supply path becomes complicated and lengthened depending on the supply location. In addition, the support portion of the rocker shaft becomes relatively thick in the axial direction of the camshaft.

[0007] In addition, the internal combustion engine of Patent Document 1 is a SOHC (Single Over Head Camshaft: Overhead Single Camshaft) internal combustion engine, but in the case of a DOHC (Double Over Head Camshaft: Overhead Double Camshaft), it may be necessary to avoid The oil supply path is formed by using fuel injection valves, etc., so the oil supply path may become more complicated

[0008] In addition, in an internal combustion engine whose fuel is gasoline, a spark plug is usually installed at the position where the above-described fuel injection valve is installed. The lubricating oil supply passage of the camshaft has problems such as difficulty in ensuring the lubricating oil quantity and reducing the size.

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