US 6,551,152 B2 · Jet-propulsive watercraft

Abstract

The present invention provides a lightweight and simply-configured watercraft of a jet-propulsive type that can maintain steering capability in a way adapted to forward movement and rearward movement of the watercraft even when throttle-close operation is performed and the amount of water ejected from a water jet pump is thereby reduced. During forward movement, when the throttle-close operation and steering operation of a steering handle are detected and an engine speed is between an idling speed and a predetermined engine speed, the engine speed is temporarily increased. During rearward movement, when the engine speed is the idling speed, the engine speed is temporarily increased in the same way. The engine speed is increased by changing a fuel injection timing of a fuel injection system, a fuel injection amount, and/or an ignition timing of an ignition system of the engine.

Claims34

Dependent claims

A jet-propulsive watercraft comprising:

a water jet pump that pressurizes and accelerates sucked water and ejects the water from an outlet port provided behind the water jet pump to propel the watercraft as a reaction of the ejecting water;
an engine for driving the water jet pump;
an engine speed sensor for detecting an engine speed of the engine;
a steering operation means that operates in association with a steering nozzle of the water jet pump;
a steering position sensor for detecting a predetermined steering position of the steering operation means;
a throttle-close operation sensor for detecting a throttle-close operation;
and
an electric control unit adapted to increase the engine speed in response to the steering position sensor detecting the predetermined steering position, the throttle-close operation sensor detecting the throttle-close operation, and the engine speed sensor detecting the engine speed smaller than a first predetermined engine speed.

5 more elements

A jet-propulsive watercraft comprising:

a water jet pump that pressurizes and accelerates sucked water and ejects the water from an outlet port provided behind the water jet pump to propel the watercraft as a reaction of the ejecting water;
an engine for driving the water jet pump, said engine including a fuel injection system;
a steering operation means that operates in association with a steering nozzle of the water jet pump;
a steering position sensor for detecting a predetermined steering position of the steering operation means;
and
an electric control unit adapted to increase an engine speed of the engine by changing a fuel injection timing of the fuel injection system, in response to the steering position sensor detecting the predetermined steering position.

3 more elements

A jet-propulsive watercraft comprising:

a water jet pump that pressurizes and accelerates sucked water and ejects the water from an outlet port provided behind the water jet pump to propel the watercraft as a reaction of the ejecting water;
an engine for driving the water jet pump, said engine including a fuel injection system;
a steering operation means that operates in association with a steering nozzle of the water jet pump;
a steering position sensor for detecting a predetermined steering position of the steering operation means;
and
an electric control unit adapted to increase an engine speed of the engine by changing a fuel injection amount of the fuel injection system, in response to the steering position sensor detecting the predetermined steering position.

3 more elements

A jet-propulsive watercraft comprising:

a water jet pump that pressurizes and accelerates sucked water and ejects the water from an outlet port provided behind the water jet pump to propel the watercraft as a reaction of the ejecting water;
an engine for driving the water jet pump, said engine including a fuel injection system and an ignition system;
a steering operation means that operates in association with a steering nozzle of the water jet pump;
a steering position sensor for detecting a predetermined steering position of the steering operation means;
and
an electric control unit adapted to increase an engine speed of the engine by changing a fuel injection timing of the fuel injection system, an ignition timing of the ignition system, and a fuel injection amount of the fuel injection system, in response to the steering position sensor detecting the predetermined steering position.

3 more elements

Dependencies are inferred from the claim text.

Jet-propulsive watercraft

Life of this patent

Jet-propulsive watercraft

Life of this patent

Abstract

Claims34