Watercraft Propulsion Control Mode Switching via Engine Speed

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Solution Overview

Problem

Conventional watercraft propulsion systems require a watercraft velocity detecting device to reduce the load on propulsion machines, which is not feasible without such a device, leading to operational limitations.

Innovation Solution

A watercraft propulsion system that includes a normal operating unit, a joy stick operating unit, a control unit, a control mode switching unit, and a detection unit, where the control unit controls propulsion machine outputs and rudder angles based on operational modes and detects engine rotational speeds to set a mode switching prohibition period, preventing mode switching unless the rotational speed falls within a safe range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a watercraft velocity detecting device is used to limit mode transition, then the load on propulsion machines is reduced, but the device complexity increases

Engineering Contradiction:

Improveload reduction on propulsion machinesVSAvoidvelocity detecting device

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses engine rotational speed as an intermediary parameter to infer watercraft velocity. Instead of directly measuring velocity with a dedicated sensor, the system uses the readily available engine rotational speed data as a proxy indicator, which correlates with watercraft velocity without requiring additional velocity detection hardware.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses existing engine parameters (rotational speed) that are already being monitored for other purposes to determine mode transition safety. This self-service approach allows the system to leverage existing sensor data rather than requiring separate velocity detection equipment.

Inventive Principle:

Principle #25Self-service

2Device complexity

If a watercraft velocity detecting device is not provided, then the device complexity is reduced, but the ability to reduce load on propulsion machines during mode transition is lost

Engineering Contradiction:

Improvevelocity detecting deviceVSAvoidload reduction on propulsion machines

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent changes the measurement parameter from direct watercraft velocity to engine rotational speed. By monitoring engine rotational speed instead of watercraft velocity, the system achieves the same protective function without requiring velocity detection equipment, as engine speed serves as a reliable indicator of the watercraft's motion state.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system replaces a mechanical velocity detection system with an electronic control system that uses existing engine sensors. Instead of adding mechanical velocity sensors, the patent uses electronic processing of engine rotational speed data to determine when mode transitions are safe.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Speed

If mode switching is allowed immediately after throttle valve closure, then the responsiveness is improved, but the load on propulsion machines increases

Engineering Contradiction:

Improvemode switching responsivenessVSAvoidload on propulsion machines

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The system performs preliminary monitoring of engine rotational speed after throttle valve closure to determine when it is safe to allow mode switching. By proactively tracking the deceleration process and identifying the appropriate moment when load becomes acceptable, the system enables timely mode transitions while protecting the propulsion machines.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control unit continuously monitors engine rotational speed and uses this feedback to dynamically determine when mode switching is appropriate. The system adjusts the mode switching timing based on real-time engine speed information, allowing transitions only when the feedback indicates that propulsion machine load is at an acceptable level.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20150307176A1Watercraft propulsion system and propulsion machine controlling method

Publication Date: 2015.10.29 YAMAHA MOTOR CO LTD

AI summary

A watercraft propulsion system includes a normal watercraft operating unit, a joy stick watercraft operating unit, a control unit, a control mode switching unit, and a detection unit. The normal watercraft operating unit includes throttle levers and a steering wheel. The throttle levers are used to adjust outputs of at least two propulsion machines mounted to a hull. The steering wheel is used to adjust rudder turning angles of the at least two propulsion machines. The joy stick watercraft operating unit includes a joy stick. The joy stick is used to move the hull in at least each of front, rear, left, and right directions. The control unit is configured and programmed to control the outputs and the rudder turning angles of the at least two propulsion machines in a normal mode in accordance with an operation of the normal watercraft operating unit or a joy stick mode in accordance with an operation of the joy stick watercraft operating unit. The control mode switching unit is configured to output a control mode switching instruction to the control unit when the control mode switching unit has received a switching operation of the control mode.