Yamaha Hatsudoki Kabushiki Kaisha

Yamaha Marine Kabushiki Kaisha

Takuya Kado

Shu Akuzawa

Makoto Ito

Tomoaki Sato

An engine includes a catalyst disposed inside an exhaust passage that guides exhaust discharged from a combustion chamber and a controller programmed to control a throttle valve and a fuel injector. If the engine is overheating, the controller is programmed to control the opening degree of the throttle valve or the injection amount of fuel from the fuel injector to decrease the rotational speed of the crankshaft and to control the injection amount of fuel from the fuel injector to set a target air-fuel ratio to a value richer than a stoichiometric air-fuel ratio.

Engine and outboard motor

A propulsion unit control system is provided for a boat having plural propulsion units provided side by side and electrically connected in association with two adjacent operation levers. The control system synchronizes engine speeds of the respective propulsion units with each other in light of inputs to the two operation levers. The control system computes a deviation between the averaged engine speed of a reference propulsion unit and the averaged engine speed of a propulsion unit to be synchronized, and corrects a throttle opening of the propulsion unit to be synchronized based on the computed deviation in order to synchronize the engine speeds of the respective propulsion units with each other.

Propulsion unit control system

A watercraft propulsion device includes an engine, a drive shaft, a propeller shaft, a rotational speed detector, and a controller. The drive shaft transmits power from the engine. The propeller shaft is rotationally driven by power transmitted from the drive shaft. The rotational speed detector detects an engine rotational speed. The controller executes a suppression control to suppress the engine rotational speed when a change rate of the engine rotational speed is equal to or larger than a prescribed value.

Watercraft propulsion device

A control device for propulsion units is adapted to synchronize the engine rotational speeds of a plurality of propulsion units arranged in a row on a vessel and operatively and electrically connected to two control levers that are positioned adjacent to each other. The control device synchronizes the engine rotational speeds by correcting the throttle opening of a target propulsion unit or units based on a deviation between the engine rotational speed of a reference propulsion unit and the engine rotational speed of the target propulsion unit. Upon cancellation of synchronization, the throttle opening correction is reduced stepwise from its corrected throttle opening to its natural throttle opening based on the position of the corresponding control lever. As such, large fluctuations in engine speeds are avoided upon cancellation of synchronization.

Control device for plural propulsion units

A predicted boat speed value generator, in accordance with one or more embodiments, receives an engine rotation signal, an intake pressure value, and other detection signals including shift position, and provides a predicted boat speed value. A control signal generator determines the fuel injection amount, the amount of air, and the ignition timing based on the predicted boat speed to provide respective control signals. The predicted boat speed value generator includes a predicted boat speed mapped value extraction process to search through the predicted boat speed value map during the constant speed operation and acceleration, based on the rotational speed and the intake pressure, to extract the predicted boat speed mapped value 'd' for output. A predicted decelerating boat speed value output process establishes the initial predicted boat speed value to provide the attenuated predicted boat speed value in every cycle.

Engine control unit systems and methods for a boat propulsion system

A shift-in operation determination device determines a shift-in operation based on a signal in accordance with an operation of a remote control lever. An ignition timing operation device retards an ignition timing of an engine based on a determination result of the shift-in operation by the shift-in operation determination device. A shift-in command device engages a shift actuator and a dog clutch with either of a forward traveling bevel gear or a rearward traveling bevel gear in a state where the ignition timing of the engine is retarded. The shift-in operation determination device works to prevent a shock which occurs at a shift-in while maintaining a stable engine output in an outboard motor.

Shift motion control device

A control device for plural propulsion units executes a control for synchronization of the engine rotational speed of a target propulsion unit with the engine rotational speed of a reference propulsion unit when one or more specified conditions are satisfied. Once synchronization control has been established, it is only cancelled if one of the specified conditions becomes no longer satisfied for a first prescribed duration or if another of the specified conditions becomes no longer satisfied for a second prescribed duration.

A propulsion unit control system is provided for a boat having plural propulsion units provided side by side and electrically connected in association with two adjacent operation levers. The control system synchronizes engine speeds of the respective propulsion units with each other based at least in part on the position of the two operation levers. The control system determines whether certain factors are satisfied before synchronizing engine speeds. The factors include, for example, whether a deviation in angular position between the two operation levers is within a prescribed range. Another factor is whether a deviation between the throttle opening of a reference propulsion unit and a propulsion unit to be synchronized equal to or less than a prescribed value. If the respective deviations are equal to or smaller than a relevant prescribed value, the engine speeds of the respective propulsion units are controlled for synchronization with each other.

Growing community of inventors

Shizuoka, Japan

Takuya Kado