Honda Motor Co., Ltd.

Shinsuke Yasui

Isao Azumagakito

Yukihiro Tsubakino

Nozomi Okada

Akio Senda

Kazuya Shindome

Dai Koike

A motorcycle engine includes a cylinder block with an axis extending perpendicularly or slightly inclined forwardly. A cylinder head includes an intake port, an exhaust port disposed on a front surface of the cylinder head opposite the intake port, an engine hanger boss, a coolant temperature sensor mounting portion, and a cam chain tensioner lifter. The intake port has an outer opening having a center disposed on a level upward of a center of an outer opening of the exhaust port. The engine hanger boss is provided on either side of the cylinder head, has a centerline that crosses the intake port, and disposed upwardly of an upper end of the outer opening of the exhaust port. The cam chain tensioner lifter and the coolant temperature sensor are in an overlapping position in a side view, downwardly of the engine hanger boss and an open end of the intake port.

Motorcycle engine

To achieve further reduction in size and weight of a cylinder head in a four-cycle engine having a connection surface formed on the cylinder head to connect a head cover set so as to follow along a plane that is inclined so as to be spaced further away from a cylinder block toward a first side wall. A camshaft holder is integrally formed on a cylinder head so as to protrude from a connection surface as viewed from an axial direction of a camshaft. An intake port is disposed in the first side wall such that an upstream end thereof is disposed at the same position as part of the bearing portion in a direction along an axis of a cylinder bore. An exhaust valve has a stem end disposed at a position protruding from the connection surface as viewed in a direction along the axial direction of a camshaft.

Cylinder head structure in four-cycle engine

An exhaust control device for a vehicle engine wherein an exhaust pipe forms an exhaust passage along with an exhaust port is connected to a cylinder head via the exhaust port. A rotary valve is capable of changing the opening area of the exhaust passage. The rotary valve being disposed in approximately the middle of the exhaust passage. The opening area of the exhaust passage is made controllable by the rotary valve while avoiding an increase in the number of component parts. A rotary valve having a turning axis located at a position offset from the center of the exhaust port is housed in a valve housing provided integrally with a cylinder head.

Exhaust control device for vehicle engine

An internal combustion engine for reducing the amount of bubbles contained in the circulated oil without reducing the ground clearance of the engine. A crankcase is provided therein with an oil suction passage makes an oil pump and an end part of a bottom wall of an oil sump chamber communicate with each other, passes between the oil sump chamber and a hanger boss, and has a lowest part located below the bottom wall of the oil sump chamber.

Internal combustion engine

An exhaust control device for a vehicle engine includes an exhaust control valve capable of changing the opening area of an exhaust passage. The exhaust control valve is disposed in exhaust passage forming means so as to be able to change a bent-internal side partial passage sectional area of the passage sectional area of an exhaust passage. Specifically the exhaust control valve is disposed at a bent portion of the exhaust passage that is closest to an exhaust valve port. With this configuration, the exhaust flow rate can be controlled satisfactorily.

In a four-cycle engine, the stiffness of a rocker shaft support portion is increased while avoiding an increase in the size of a cylinder head. The rocker shaft support portion that supports a rocker shaft is integrally formed on the cylinder head so as to be disposed between an engine valve and a camshaft as viewed from an axial direction of the camshaft and the rocker shaft. First reinforcement ribs are integrally disposed in a protruding condition on a plane orthogonal to an axis of a rocker shaft on a side face of rocker shaft support portions opposite a side of a camshaft.

Growing community of inventors

Saitama, Japan

Shinsuke Yasui