Honda Motor Co., Ltd.

Naoki Kono

Kohji Minami

Masaki Yoneyama

Yoshiki Nagahashi

Isamu Takahashi

Fumiaki Okubo

Hiroshi Kuribara

Hirotaka Haze

An internal combustion engine is provided with a crankcase partitioned into an upper section and a lower section. A fastening bolt is provided for fastening the upper and lower crankcase sections together in the vicinity of a crankshaft. A bolt hole is formed in the crankcase, and the fastening bolt is inserted and tightened in the bolt hole. An opening is formed at an end of the bolt hole within the upper crankcase, the end of the bolt hole is made to communicate with this opening, and the end of the fastening bolt protrudes into the opening when the engine is assembled, to lighten the crankcase, and in order to avoid concentrating stress in the bolt hole near the end of the bolt.

Internal combustion engine having crankcase with stress-relieving wall structure

An integrated power unit for a small vehicle is configured to permit a compact engine design in a power unit having a crankcase that is split into upper and lower portions. The power unit includes a crankshaft supported by the crankcase and oriented transverse to the running direction of the vehicle. A transmission shaft is rotatably supported in a transmission chamber formed on the rear side of the crank chamber. The respective split surfaces of the upper and the lower crankcase portions are provided plural fastening boss portions arranged as vertically opposed pairs. The plural fastening boss portions are respectively joined using fastening bolts to integrate the upper crankcase and the lower crankcase, thereby forming the crankcase. A clutch is disposed at one end of the transmission shaft, and the rearmost fastening boss portions overlap with a rear portion of the clutch in the front-rear direction of the vehicle.

Integrated power unit including split crankcase with reinforced fastening arrangement, and vehicle including same

To provide a layout structure of a hydraulic control valve for a valve train in an internal combustion engine which can reduce the influence of heat from the cylinders and can avoid the impairment of the external appearance of the internal combustion engine. An internal combustion engine has a valve operation characteristics changing mechanism that changes the operation characteristics of at least one of an intake valve and an exhaust valve. A hydraulic control valve for a valve train controls the pressure of a hydraulic fluid supplied to the valve operation characteristics changing mechanism. The hydraulic control valve is located on the left side surface of right and left crankcases that support and cover a crankshaft at a position below cylinders.

Layout structure of hydraulic control valve for valve train in internal combustion engine

In an engine having a generator mounted thereon, an oil passage is formed within the engine's crankcase to supply oil to an oil jet for cooling one or more pistons. In addition, oil is supplied to an oil jet for cooling the generator, using the oil passage in common with the oil supply for cooling the piston, without requiring a separate, dedicated oil passage for the generator. The cooling oil delivery structure is provided for cooling the generator which is located at one end of the crankshaft. The oil passage for cooling pistons, which includes an oil jet for cooling each respective piston by jetting oil to the piston, is arranged on an axis substantially parallel to the crankshaft. A generator-cooling oil jet is provided on the crankcase at a terminal end of, and in fluid communication with the oil passage for cooling the pistons.

Cooling oil delivery structure for a vehicular generator, and engine including same

An internal combustion engine is provided with an internal piston cooling system that jets oil from an oil jet onto a surface of a piston during engine operation, to effectively cool the piston. In the piston cooling system of the internal combustion engine, each piston being arranged to reciprocate in a cylinder bore of a cylinder block, and oil is jetted from individual oil jets to each piston, respectively. An oil reservoir is formed in a crankcase journal wall, that journals a crankshaft of the engine. In the crankcase, oil supply passages are provided for supplying oil from a hydraulic supply source to the oil reservoir, and in turn, oil is operatively supplied from the oil reservoir to the oil jets via a passageway.

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Saitama, Japan

Naoki Kono