Yamaha Hatsudoki Kabushiki Kaisha

Masao Koriyama

Tatsuyuki Masuda

Noritaka Matsuo

Hitoshi Uema

A lightweight high-strength cylinder block that is configured so as to provide an enlargement at one end thereof that defines a bell housing. The enlargement is provided with cavities, however, so as to lighten the weight of the cylinder block without substantially reducing its strength. At least one of these cavities can provide for communication of oil return and/or crankcase ventilating gases and also may function as a thermostat housing. An embodiment wherein the cylinder block extends below the crank shaft axis to form the upper portion of the crankcase is also disclosed.

Engine cylinder block

A plated cylinder and method for creating a plated cylinder are disclosed. The cylinder is formed by a cast cylinder block and includes a cylinder wall having one or more casting pits or pores. The casting pits have a maximum dimension which is less than a dimension which is spanned by a plating during a plating process in which plating material is deposited on said wall as said material flows along said wall at a velocity. In the method of producing the plated cylinder, the cylinder wall is inspected to determine the dimension of the casting pits, and if of a small enough dimension, plating is applied in a high speed plating process in which plating material is directed at a velocity along the cylinder wall and deposited thereon, spanning all casting pits.

Plated cylinder arrangement

A sleeveless cylinder block for an automobile engine, motorcycle engine or the like having at least one cylinder such as that made of an aluminum ally, the inside surface of which is plated, is characterized in that a marginal portion from the bottom end of the inside surface of the cylinder on the side of the cylinder skirt and the remaining part of the cylinder block lower than the marginal portion are not plated, whereby only a target area inside the cylinder is securely plated, and further the area between the bottom of the cylinder and the cylinder skirt is strengthened.

Sleeveless cylinder block without marginal plating coating

A variable compression ratio mechanism for a two cycle diesel engine embodying auxiliary exhaust passages and auxiliary exhaust ports that communicate with the cylinder above the main exhaust ports and in which control valves are positioned for controlling the opening and closing of the auxiliary exhaust ports to change the effective compression ratio of the engine to minimize dead space between exhaust control valves and the auxiliary exhaust ports, the exhaust control valves are positioned in close proximity to the cylinder and comprise valve elements that operate in bores that are disposed substantially parallel to the cylinder bore. Both rotary and reciprocating type valves are disclosed and various mechanisms are disclosed for interlinking the control valves for simultaneous operation. In addition, the positioning of the auxiliary exhaust passages permits the formation of a cooling jacket between them that cools not only the auxiliary exhaust passages but also the control valves and the main exhaust passage. Embodiments are shown of adapting these principals to multiple cylinder engines and in which the main exhaust passages are formed in an acute angle to a plane containing the axes of the cylinder bores so as to permit a compact construction.

Variable compression device for two cycle diesel engine

A two cycle crankcase compression diesel engine having reed type checks valves for controlling the flow of air into a crankcase chamber though an intake passage. The engine is provided with a separate lubricating system in which no lubricant for lubrication is delivered to the intake passage upstream of the check valve. The closing noise of the check valve is dampened by delivery small quantities of lubricant to the intake passage solely for this purpose. In one embodiment, this lubricant is derived from the crankcase and in another embodiment the lubricant is supplied directly from the separate lubricating system.

Growing community of inventors

Iwata, Japan

Masao Koriyama