Honda Giken Kogyo Kabushiki Kaisha

Masashi Amano

Masahiro Asai

Yoshiyuki Horii

Takaharu Kurosaki

Shinichi Isomura

Hideki Noritake

Masami Takubo

To provide a compact two-cylinder engine in which adjacent cylinders are located close to each other. In the two-cycle engine of the present invention, the scavenging passages of scavenging ports adjacent to the exhaust ports are flat or elongate in their cross section and extend to the sides of the exhaust ports. This structure allows the cross-sectional area of the scavenging passages to be sufficient, but allows the width of the cylinder section between adjacent cylinders to be decreased. Furthermore, in the two-cycle engine of the present invention, the exhaust passages of the cylinders are arranged in the direction substantially orthogonal with the direction of alignment of the cylinders, and the exhaust control valves are positioned near the exhaust ports in order to control an opening amount of the exhaust ports. The exhaust control valves are rotatably supported by a pivot extending substantially in parallel with the juxtaposed direction of the cylinders, and are turned in a plane which is parallel with the opening direction of the exhaust ports.

Two-cycle engine

To provide a structure for attaching exhaust control valves near exhaust ports in a two-cycle engine, the exhaust control valves variably controlling open areas of the exhaust ports. The cavity for receiving the exhaust control valves is formed near the upper edges of the exhaust ports on the cylinder block. The holder member is interposed between the cylinder block and the exhaust manifold, is attached to the pivot for supporting the exhaust control valves. A flange is provided for connection with the cylinder block. Therefore, the exhaust control valves are disposed near the upper edges of the exhaust ports. It is not necessary to form bearings on the cylinder block using a complicated process. Complicated parts such as bearings are collectively formed on the holder member that is independent and compact and easily machined. The pivot extends across the exhaust passages that are formed downwardly in order to detour around the pivot. A jet-propelled boat is provided with a saddle seat in which the power unit is neatly and compactly arranged in a limited space.

A control valve is disposed in a communication passage for communication between a combustion chamber and a chamber portion adjacent to the combustion chamber, and through the communication passage at least one of a fuel and an air-fuel mixture, and a highly compressed gas, are supplied or charged into the combustion chamber and the chamber portion adjacent thereto, respectively. The control valve includes a first control valve disposed in the first communication passage and a second control valve disposed in the second communication passage, the first control valve causes the first communication passage to open at a timing near closing of an exhaust port and causes it to close halfway in a compression stroke. The second control valve causes the second communication passage to open at a timing near closing of the scavenging ports and causes it to close prior to closing of the first communication passage.

Two-cycle internal combustion engine

A two-cycle internal combustion engine includes a control valve disposed within a communicating passage between the combustion chamber and a chamber portion adjacent to the combustion chamber. The control valve is for controlling the opening and closing of the communicating passage. Blowby of an air-fuel mixture supplied to the combustion chamber can be prevented to reduce fuel consumption and increase the exhaust gas purifying performance. A communicating passage portion between the control valve and the fuel supply opening is configured to spray fuel from the control valve to a part or all of a wall surface of the communicating passage portion and the wall surface of the communicating passage portion is shaped to guide the fuel into the combustion chamber.

A gear shifting mechanism for a transmission, capable of driving the gearshift drum of the transmission for turning in both a shift-up direction and a shift-down direction by operating a switch or a valve. A sector gear is formed on a gearshift arm fixed to a gearshift spindle to drive a gearshift drum. A driving gear, engaged with an idle gear engaged with the sector gear, is fixed to the rotary shaft of a pneumatic rotary actuator. The pneumatic rotary actuator is attached to the transmission case of a transmission, and compressed air is supplied into either a first pressure chamber or a second pressure chamber of the rotary actuator through a solenoid selector valve to turn the rotary shaft in either the normal direction or the reverse direction. The present invention provides an auxiliary gear shifting system which enables gear shifting operation without the operator using his/her foot. An actuator operatively connected to a gearshift arm is driven by compressed air reserved in a main frame and supplied thereto through an air valve and a pneumatic switch. Part of the compressed air supplied to the actuator is supplied to a pressure switch to make an ignition unit reduce the output of the engine temporarily during the operation of the actuator. The pneumatic switch can be remote-controlled by an operator's hand through a remote-control wire by operating a switch lever disposed near the grip of a handlebar.

Growing community of inventors

Saitama, Japan

Masashi Amano