Honda Motor Co., Ltd.

Aritoshi Imazato

Kentaro Yamada

Yoshihiro Fujiyoshi

Takeya Harada

Kazuaki Shimoyama

Naoto Hirayama

A timing transmission mechanism (T) in an engine is formed of a chain transmission system (C) that is formed from a drive sprocket () mounted on a crankshaft (), a driven sprocket () mounted on a pump input shaft () of a high pressure fuel pump (P), and a chain () wound around the drive sprocket () and the driven sprocket (); and a gear transmission system (G) that is formed from a drive gear () mounted on the pump input shaft () coaxially with the driven sprocket () and a driven gear () mounted on a camshaft () and meshing with the drive gear (). This enables a timing transmission mechanism to be provided that can increase the degree of freedom in layout of the high pressure fuel pump without causing any increase in the number of components, the weight, or the backlash.

Timing transmission mechanism in engine

An oil communication passage () is formed so as to run through a wall portion () separating an oil collector () and an oil drop hole () formed in an engine cylinder head (), and oil that has collected in the oil collector () can therefore be guided to the oil drop hole () via the oil communication passage (). An oil supply passage () and a retaining hole () for retaining a hydraulic tappet (), which is operated by oil supplied from the oil supply passage (), are formed in the wall portion () of the cylinder head (), and the oil supply passage () and the oil communication passage () communicate with each other via the retaining hole (); therefore, even if part of the oil supplied from the oil supply passage () to the hydraulic tappet () leaks into the retaining hole (), the oil can be discharged by utilizing the oil communication passage ().

Cylinder head oil passage structure

An internal combustion engine has a camshaft holderattached to a cylinder head, and two camshaftsandare rotatably supported by the camshaft holder. A high-pressure pumphas a driving shaftrotatively driven by the camshaft. An accessory holderprovided with a mounting seatto which the high-pressure fuel pumpis attached is formed integrally with a lower camshaft holderincluded in the camshaft holder. The mounting seatis formed integrally with the accessory holderand is provided with a through holein which the driving shaftis received. Thus the cylinder headis formed in a small size and a light weight. The accessory holdercan be formed with a high rigidity in a small size.

Growing community of inventors

Saitama, Japan

Aritoshi Imazato