Yamaha Hatsudoki Kabushiki Kaisha

Akihiko Ohokubo

Yu Motoyama

Yoshihiko Moriya

Miyoshi Ishibashi

A direct cylinder injected engine in several different embodiments which are specifically illustrated as two-cycle engines but which can also be used in four-cycle engines. The fuel injector is positioned so as to minimize escape of fuel from the exhaust port in the two-cycle engine applications. In addition, multiple or extended spark plug firing is accomplished under difficult running conditions and wherein fuel vaporization may be incomplete. This will ensure complete combustion. Various control routines and strategies are disclosed that control the number or time of injection depending upon such factors as engine speed, load, speed variation, air fuel ratio variations and pressure variations.

Ignition control system for engine

A number of embodiments of two-cycle crankcase compression direct injected internal combustion engines wherein engine speed is controlled under at least some running conditions by cylinder disabling. Exhaust systems including exhaust control valves for precluding the passage of cooler gasses from the disabled cylinders to the operating cylinders through their exhaust ports are illustrated in varying forms and for various types of engines.

Growing community of inventors

Iwata, Japan

Akihiko Ohokubo