Sanshin Kogyo Kabushiki Kaisha

Yamaha Hatsudoki Kabushiki Kaisha

Takehisa Suzuki

Shigeyuki Ozawa

Hiroaki Fujimoto

Ryoichi Nakase

Hitoshi Motose

Kimihiro Nonaka

Yukio Matsushita

Kazumasa Tanimoto

Naoto Matsumoto

An outboard motor includes the direct fuel injection system. The outboard motor also includes an ECU that monitors various engine operating conditions and controls various engine operating parameters that are at least partially dependent on the positioning of the transmission. In instances in which the transmission is positioned in a neutral location, the load is decreased and therefore the ECU outputs one set of parameters. In similar low-speed operations, when the transmission is placed in a drive arrangement, the ECU outputs a second set of parameters due to the increased load. Several control routines are disclosed which facilitate low-speed operation, over-rev limiting, and engine warm-up.

Control system for outboard motor

An arrangement of an exhaust gas collection port within an exhaust system of a small watercraft increases the accuracy of an associated probe's readings. The port is located upstream of a point where cooling water is introduced into the exhaust system for silencing purposes. As a result, the ingress and egress of exhaust gases flow into and out of the port is generally unimpeded by the cooling water. The tendency of water to enter and clog the port is also reduced. The precision of the associated exhaust probe measurements consequently is greatly increased.

Watercraft exhaust system

A number of embodiments of a personal watercraft are disclosed which have a catalytic exhaust system for treating and purifying exhaust gases. In all of the embodiments, the catalyst is positioned and disposed so as to be protected from water. In addition, arrangements are provided for cooling the catalyst, for discharging at least a portion of coolant upstream of the catalyst, for circulating ventilating air across it, for isolating it from other components such as the fuel tank, and for permitting its flushing with fresh water after operating in a salt water environment.

Watercraft catalytic exhaust system

A catalytic exhaust system for an outboard motor wherein the catalyst is positioned in the drive shaft housing to remove this source of heat from the power head. However, the catalyst is contained within a sealed compartment in the drive shaft housing lower unit. In order to protect the catalyst from water, a trap section is positioned in the power head and this is water cooled by a source of water which has not passed through the engine for its cooling prior to delivery to the trap section. In addition, the guide plate that separates the power head from the drive shaft housing and through which the exhaust gases pass is also water cooled. An arrangement is incorporated for permitting replacement and servicing of the catalytic converter. Although both above the water and below the water exhaust gas discharges are employed, all gases flowing to the atmosphere must pass through the catalytic converter. An arrangement is also provided for passing flushing water through the catalyst while still in the outboard motor. The flushing operation is such that the water flows in the opposite direction from the exhaust gases to assist in removing foreign particles.

Exhaust system for outboard motor

An exhaust silencer for an outboard engine including an expansion chamber for reducing the exhaust noise. A reflection chamber having an open end and a closed end is placed with its open end communicating with the expansion chamber at a location which is reversely spaced from the open end of an exhaust pipe discharging into the expansion chamber. This enables the engine to be operated optimally in a plurality of engine speed ranges and for the silencer to occupy a minimal volume.

Growing community of inventors

Hamamatsu, Japan

Takehisa Suzuki