Yamaha Hatsudoki Kabushiki Kaisha

Hideaki Ito

Masanori Miyamoto

Makoto Kosugi

Hiroshi Hasegawa

Noritaka Matsuo

Hidenori Suhara

Kohsei Maebashi

A number of embodiments of precombustion chamber configurations for two-cycle crankcase compression diesel engines. The precombustion chamber and its communicating throat are oriented so as to maintain a uniform fuel distribution in the precombustion chamber and to provide good flow into the main combustion chamber that will provide a homogeneous mixture without the flow being directed toward the exhaust port at the time the exhaust port is open. A number of embodiments show constructions that permit uniformity of tumble action in the precombustion chamber and a high velocity for the tumble action to improve turbulence and mixing. All of these factors go together to reduce NOx emissions.

Prechamber for diesel engine

A two-cycle crankcase compression diesel engine having a scavenge control system for controlling the amount of scavenging flow and an exhaust control system for controlling the effective compression ratio and the effective flow area of the exhaust system. These controls are operated during normal engine running conditions at most speed ranges from a three dimensional map. However, special control routines and valve operating arrangements are provided for pre-starting, starting, idle, engine braking or deceleration and rapid acceleration so as to improve the running under these transient or non-normal conditions.

Operational control device for two-cycle engines

Embodiments of lubricating systems and methods for two cycle, crankcase compression, diesel engines wherein certain running components of the engine such as the crankshaft and pistons are each supplied with their own lubricating systems including independently operating lubricating pumps, each system is controlled so as to supply a finite amount of lubricant to the engine and then sense the engine running conditions to determine when the lubricant will have been consumed before additional lubricant is supplied. In addition, a control routine and structure is disclosed wherein lubrication is supplied to the engine before starting is initiated and wherein the amount of lubrication supplied is varied during break-in.

Lubricant control

A two-cycle diesel engine and means for operating it to improve the performance by increasing the compression ratio by the closing of a supplemental exhaust port under light loads and low speeds. In order to reduce combustion chamber temperature and reduce nitrous oxide emissions, the injection timing is advanced an additional increment during the closing of the supplemental exhaust port. Various control strategies are described which involve either quickly raising the compression ratio and retarding the injection timing.

Two-cycle diesel engine

A diesel engine operating on the two cycle crankcase compression principle and having a means for reducing nitrous oxide emissions under low and medium range speeds. This is done by throttling the scavenge air flow which can be accomplished either by throttling the air admitted to the crankcase chamber or bypassing a portion of the compressed air from the crankcase chamber back to the induction system. In addition, an exhaust control valve is provided for raising the compression ratio and the injection timing is advanced when the scavenge air is reduced so as to further improve the control of hydrocarbon and carbon monoxide emissions.

Two cycle diesel engine

A lubricating system for a two cycle crankcase compression engine wherein a recirculating lubricating system is provided for lubricating at least one main bearing of the crankshaft and a second non recirculating lubricating system is provided for lubricating other components of the engine. A drain system drains lubricant accumulating within the crankcase back to the engine through its induction system upstream of a check valve contained therein.

Lubrication system for two cycle engine

An apparatus and method for maintaining the control of lubricant to a two cycle engine so as to provide adequate lubrication without over lubrication and deleterious exhaust conditions, such as smoke. The system includes a lubricant pump that has both its output and its timing of discharge variable. Under one range of running conditions, the normal conditions, the output of the pump is maintained constant and the timing of the output is varied. Under high speed, high load conditions, the time of operation of the pump is held constant and the output time of the pump is varied.

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Iwata, Japan

Hideaki Ito