Straddle Vehicle Harness Layout Reducing Weight

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In motorcycles, the conventional layout of electric components in the electric power supply system results in long harnesses, increasing weight and cost, and making assembly difficult due to the placement of components like the relay box and fuse box under the seat, leading to thick, heavy, and inflexible wiring.

Innovation Solution

Reconfiguring the layout to place the fuel tank and air cleaner rearward, creating a larger electric component mounting space that allows for closer placement of components like the relay box, regulator, and fuse box, reducing harness length and facilitating heat radiation while maintaining sufficient fuel tank volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the relay box and fuse box are placed under the seat in conventional layout, then the components can be accommodated, but the harness becomes long, increasing weight and cost

Engineering Contradiction:
Improvecomponent accommodationVSAvoidharness weight
Core Design Contradiction:
Ease of manufactureVSWeight of moving object

Solution Approach 1:

The patent relocates the relay box and fuse box from the conventional under-seat position to the front portion of the vehicle body, specifically in the space between the head pipe and the fuel tank/air cleaner assembly. This spatial reconfiguration in a different dimensional arrangement reduces harness length by positioning components closer to each other and to the battery, thereby reducing weight without compromising component accommodation capability

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If the relay box and fuse box are placed under the seat, then the components can be mounted, but the harness becomes thick and difficult to assemble

Engineering Contradiction:
Improvecomponent mountingVSAvoidassembling ease
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

By repositioning the relay box and fuse box to the front portion of the vehicle body in a different spatial arrangement, the harness routing becomes more direct and less convoluted. This dimensional reconfiguration allows for easier assembly operations as the thick harness requires fewer bends and navigates a shorter path between components

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Temperature

If the regulator is placed on the air cleaner to block heat, then heat radiation is facilitated, but no extra space remains for other electric components

Engineering Contradiction:
Improveheat radiationVSAvoidavailable space
Core Design Contradiction:
TemperatureVSArea of stationary object

Solution Approach 1:

The patent segments the vehicle body space into distinct functional zones: the front portion between the head pipe and fuel tank/air cleaner is dedicated to electric components (relay box, fuse box), while the air cleaner area maintains its heat management function. This spatial segmentation allows both heat radiation capability and component accommodation to coexist without interference

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The regulator placement strategy is reconsidered by utilizing the newly created front space for electric components. The air cleaner can maintain its position for heat blocking while the relay box and fuse box are positioned in the front portion, effectively using different spatial dimensions to resolve the space conflict

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Area of stationary object

If the fuel tank is disposed at a rearward position, then electric component mounting space is ensured, but the overall vehicle layout must be reconfigured

Engineering Contradiction:
Improveelectric component mounting spaceVSAvoidlayout complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent utilizes the space in the front portion of the vehicle body, between the head pipe and the rearward-positioned fuel tank/air cleaner assembly, to accommodate the relay box and fuse box. This three-dimensional spatial optimization creates adequate mounting space for electric components while maintaining a coherent overall vehicle layout that does not require excessive reconfiguration

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

This configuration reduces the weight and cost of harnesses, simplifies assembly, and improves heat management for electric components, while ensuring efficient air intake and protection from rain.

Implementation Method 1

the regulator is placed on an upper surface of an air cleaner in an air-intake system to block heat radiated from the engine placed therebelow, and heat radiation from the regulator is facilitated by air flowing through an interior of the air cleaner

Methodology Applied
Scientific EffectHeat radiation: Thermal Radiation

Data Source

PatentEP2727804B1Straddle vehicle
Publication Date: 2020.04.29 KAWASAKI JUKOGYO KK
  • EP2727804B1 patent drawingFigure 1
  • EP2727804B1 patent drawingFigure 2
  • EP2727804B1 patent drawingFigure 3

AI summary

In a straddle vehicle such as a motorcycle, a harness in an electric power supply system which is thick, has a great weight, and is not easily mounted can be reduced in length as much as possible so that a weight and cost can be reduced, and an assembling work can be made easier. An air cleaner and a fuel tank are disposed at a relatively rearward position such that the air cleaner and the fuel tank are disposed behind and distant from the head pipe to provide an electric component mounting space between the air cleaner and the fuel tank, and the head pipe, and a regulator, a relay box and a fuse box are disposed in the electric component mounting space. The fuel tank is disposed at a relatively rearward position such that its rear end portion is positioned behind and below a rear end of a main frame.