Honda Giken Kogyo Kabushiki Kaisha

Junji Yamano

Yoshiaki Iizuka

Shigekazu Tanaka

Shigemasa Kajiwara

Katsuaki Shiiki

Toshio Abe

Keiji Miura

An SOHC-type engine in which first and second insertion/removal guide sections for guiding the insertion and removal of first and second spark plugs, respectively, are provided on a cylinder head including an intake valve and the first spark plug disposed therein and arranged along an axis of a camshaft, and an exhaust valve and the second spark plug disposed therein and arranged along the axis of the camshaft.

SOHC type engine

In multi-cylinder engine in which an intake valve and a first spark plug arranged side by side along an axis of a camshaft and an exhaust valve and a second spark plug arranged side by side along the axis of the camshaft are disposed in a cylinder head for every combustion chamber, the position of a central portion of an upstream end of an intake port provided in the cylinder head with the intake valve interposed between the intake port and each of the combustion chambers and the position of a central portion of a downstream end of an exhaust port provided in the cylinder head with the exhaust valve interposed between the exhaust port and each of the combustion chambers are set to correspond with each other in the direction along the axis of the camshaft. Thus, the length of the cylinder head is reduced.

Multi-cylinder engine

An engine cylinder head in which a water jacket and an EGR passage are formed therein, the EGR passage opening into an exhaust passage at one end and opening into a side of an intake side at the other end thereof, the engine cylinder being characterized in that the EGR passage is provided outwardly in a cylinder arrangement direction of head bolt pass-through holes formed in one end of the engine cylinder head in the cylinder arrangement direction. Thus, because the EGR passage can be made much longer, the cooling capacity for re-circulating gas can be improved. Moreover, because the EGR passage can be provided without head bolts being spaced apart from the combustion chamber, the surface pressure around combustion chambers in the cylinder head relative to a cylinder block can be prevented from being lowered.

Engine cylinder head

A valve operating system includes a connection switch-over device provided in a plurality of cam followers. The connection switch-over device has a piston moved in response to a change in hydraulic pressure in a hydraulic pressure chamber. A roller shaft is disposed on at least one of the cam followers and has a roller carried thereon to come into rolling contact with a valve operating cam. In this valve operating system, the hydraulic pressure chamber and a communication passage, which permits an oil supply passage to communicate with the hydraulic pressure chamber, are defined in a particular one of all the cam followers, which moves a smallest amount when the connection switch-over device is in its disconnecting state. The roller shaft, having the roller rotatably carried thereon, is mounted on the cam follower other than the particular one cam follower. Thus, it is possible to avoid an increase in size of the particular one cam follower, and avoid a complicated assembling operation and passage construction. Moreover, the valve operating load is reduced to a minimum by using the roller.

Growing community of inventors

Wako, Japan

Junji Yamano