Outboard Motor Fuel Supply Layout to Prevent Suction Pump Vapor Lock

Solution Overview

Problem

Conventional outboard motors suffer from insufficient fuel supply to the engine due to vapor lock at the suction pump, which is caused by a limited fuel suction capacity in the single fuel supply mechanism.

Innovation Solution

The outboard motor is equipped with a plurality of fuel supply mechanisms, each comprising a suction pump, a vapor separator tank, and a supply pump, which distribute the suction load and vapor generation, thereby reducing the risk of vapor lock and ensuring consistent fuel supply to the engine.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single fuel supply mechanism is used, then the device complexity is reduced, but the reliability of fuel supply deteriorates due to vapor lock at the suction pump

Engineering Contradiction:

Improvefuel supply mechanism configurationVSAvoidfuel supply reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The fuel supply system is divided into multiple independent fuel supply mechanisms, each capable of independently supplying fuel to the engine. This segmentation allows the system to maintain fuel supply reliability even if one mechanism experiences vapor lock, as other mechanisms can continue operating.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the quantity parameter of the fuel supply mechanism from one to multiple units. This parameter change increases the total fuel suction capacity and distributes the vapor generation load, preventing vapor lock conditions that would occur in a single mechanism system.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If a single fuel supply mechanism is used, then the manufacturing cost is reduced, but the fuel suction capacity is insufficient leading to vapor lock

Engineering Contradiction:

Improvemanufacturing costVSAvoidfuel suction capacity

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The fuel supply system is divided into multiple independent fuel supply mechanisms, each capable of independently supplying fuel to the engine. This segmentation allows the system to maintain fuel supply reliability even if one mechanism experiences vapor lock, as other mechanisms can continue operating.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the quantity parameter of the fuel supply mechanism from one to multiple units. This parameter change increases the total fuel suction capacity and distributes the vapor generation load, preventing vapor lock conditions that would occur in a single mechanism system.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The implementation of multiple fuel supply mechanisms reduces or prevents fuel shortages to the engine, enhancing the reliability and efficiency of the outboard motor by distributing the suction load and vapor generation across multiple units.

Implementation Method 1

a suction pump to suck in liquid fuel stored in a fuel tank

Methodology Applied

Scientific EffectSuction: Suction

Implementation Method 2

a vapor separator tank to store liquid fuel sucked in by the suction pump and separate the liquid fuel and the vapor

Methodology Applied

Scientific EffectVapor separation: Cyclone Separation

Data Source

PatentUS12534169B2Outboard motor and boat

Publication Date: 2026.01.27 YAMAHA MOTOR CO LTD

AI summary

An outboard motor includes an engine and a plurality of fuel supply mechanisms each including a suction pump to suck in liquid fuel stored in a fuel tank in a hull, a vapor separator tank to store liquid fuel sucked in by the suction pump and separate the liquid fuel and vapor, and a supply pump to supply the liquid fuel stored in the vapor separator tank to the engine.