Yamaha Hatsudoki Kabushiki Kaisha

Ryusuke Kato

Yu Motoyama

Yoshihiko Moriya

Masaki Torigoshi

Toshihiko Takahashi

Yuuji Araki

Hiroki Tanabe

Akira Ishizaki

A secondary air supply system includes a CPU, a ROM, an air supply pipe, and an air amount adjusting valve. One end of the air supply pipe is connected to an air cleaner box and the other end is connected to an exhaust port. Secondary air in the air cleaner box is supplied to the exhaust port through the air supply pipe. An amount of the secondary air to be supplied from the air supply pipe to the exhaust port is adjusted by the air amount adjusting valve. A target air-fuel ratio depending on a state of the engine is stored in the ROM. The CPU controls the air amount adjusting valve based on the state of the engine so that an air-fuel ratio in the exhaust port is the target air-fuel ratio.

Secondary air supply system and vehicle

In an exhaust system, a first oxygen sensor is attached to an exhaust pipe connected to a standard cylinder in which the amount of injected fuel is the closest to the average of the amounts of fuel injected in a plurality of cylinders. A controller calculates the air-fuel ratio of the standard cylinder based on the value detected by the first oxygen sensor. Then, based on the difference between the calculated air-fuel ratio of the standard cylinder and a predetermined target air-fuel ratio, the amount of correction to the amount of fuel injected in the standard cylinder is determined such that the air-fuel ratio of the standard cylinder is equal to the target air-fuel ratio. Furthermore, based on the amount of correction to the amount of fuel injected in the standard cylinder, the amounts of correction of the other cylinders are determined.

Exhaust system, and engine device and vehicle with the same

An exhaust system includes a first exhaust pipe group, a first catalyst device, and a second exhaust pipe group. A first coupling pipe of the first exhaust pipe group includes spaces in communication with respective first exhaust pipes. A second coupling pipe of the second exhaust pipe group includes spaces in communication with respective second exhaust pipes. The first exhaust pipe group and the second exhaust pipe group are joined such that the respective spaces are opposed to one another, with the first catalyst device interposed therebetween.

Two embodiments of fuel injection systems for two cycle crankcase compression internal combustion engines that employ two fuel injectors. One fuel injector injects into the combustion chamber while another injects into the induction system of the engine. A simplified regulating system is incorporated so that the first injector receives fuel under a higher pressure than the second injector.

Fuel injection system

A fuel injection system for engines for improving performance and fuel economy. The fuel injector controlled along with an exhaust port timing control mechanism so that fuel injected into the engine will not pass out of the exhaust port under most engine running conditions. The invention is disclosed particularly in conjunction with a two cycle crankcase compression engine wherein it has particular utility. The timing of the opening and closing of the exhaust port is changed by means of an exhaust control valve that obstructs the exhaust port under certain running conditions so as to delay its opening and closing.

Injection arrangement for improving fuel consumption

A fuel injection system and control for a two cycle crankcase compression internal combustion engine wherein air and fuel are directly injected into the combustion chamber of the engine and the idle speed is maintained constant by varying the timing of fuel injection. Fine tuning of the idle speed is further accomplished by changing the duration of fuel injection under certain conditions.

Growing community of inventors

Shizuoka, Japan

Ryusuke Kato