Yamaha Hatsudoki Kabushiki Kaisha

Kousei Maebashi

Michihisa Nakamura

Tatsuyuki Masuda

Hidenori Suhara

Yu Motoyama

Noritaka Matsuo

Hidehiro Nishimura

A two cycle crankcase compression internal combustion engine wherein a single fuel injector is mounted in the cylinder block and can inject either directly into the combustion chamber or into the induction system through the crankcase chamber through a window in the piston. A control strategy is disclosed wherein the injection occurs primarily into the induction system during either or both of startup and low temperature.

Operating method of two stroke direct injected engine

An engine measurement and control methodology wherein the engine combustion rate and IMEP are measured by measuring the in-cylinder pressure at specific crank angles and utilizing a basic reading of pressure in the combustion chamber when it will be near to atmospheric, and also at at least one point in time after ignition begins and before top dead center. The measured data can be employed for fine tuning the engine control to obtain optimum performance.

Engine control system and method

An exhaust control valve arrangement for a two cycle internal combustion engine for altering the compression ratio to provide optimum running under all conditions. An arrangement is provided or cleaning the exhaust control valve and its surrounding cooperating surfaces of the engine upon shutting off of the engine to preclude the formations of deposits that can cause sticking of the valve element. The valve element is rotated through a number of cycles after the engine is stopped through a wider range than during its normal valving operation for removing deposits. The number of cycles is chosen in response to an engine condition such as length of time of running or amount of lubricant supplied to the engine. Various valve arrangements are disclosed that improve the cleaning operation and permit cleaning even while the engine is running.

Exhaust control valve for engine

An exhaust control valve arrangement for a two cycle internal combustion engine for altering the compression ratio to provide optimum running under all conditions. An arrangement is provided for cleaning the exhaust control valve and its surrounding cooperating surfaces of the engine upon shutting off of the engine to preclude the formations of deposits that can cause sticking of the valve element. The valve element is rotated through a number of cycles after the engine is stopped through a wider range than during its normal valving operation for removing deposits. The number of cycles is chosen in response to an engine condition such as length of time of running or amount of lubricant supplied to the engine. Various valve arrangements are disclosed that improve the cleaning operation and permit cleaning even while the engine is running.

Growing community of inventors

Iwata, Japan

Kousei Maebashi