Motorcycle Throttle Body Layout for Faster Intake Air Response

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Solution Overview

Problem

The existing straddled vehicles face challenges with a long downstream portion of the intake pipe, leading to delayed intake air adjustment and potential gas backflow, which affects fuel consumption and exhaust gas purification.

Innovation Solution

The gear box is positioned to overlap the fuel pipe end in the straddled vehicle's side view, allowing the throttle valve to be closer to the fuel injection device, thereby shortening the intake pipe downstream portion and preventing interference between the gear box and fuel pipe.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the gear box is disposed more rearward than the fuel pipe end to avoid interference, then the throttle valve cannot be positioned close to the fuel injection device, but this results in a long downstream portion of the intake pipe causing delayed intake air adjustment and gas backflow

Engineering Contradiction:
Improveintake air adjustment responseVSAvoidcomponent layout complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent transitions from a one-dimensional linear arrangement (throttle valve far from fuel injection device) to a two-dimensional spatial arrangement where the gear box overlaps the fuel pipe end in side view while being positioned above it in plan view. This dimensional change allows the throttle valve to be located close to the fuel injection device, shortening the downstream portion and improving intake air adjustment response without causing interference between components.

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

2Reliability

If the downstream portion of the intake pipe is long to accommodate component spacing, then the volume of the downstream portion increases, but this causes gas backflow from the engine to the downstream portion reducing fuel consumption and exhaust gas purification efficiency

Engineering Contradiction:
Improveexhaust gas purification efficiencyVSAvoiddownstream portion length
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

By repositioning the gear box to overlap the fuel pipe end in side view and locate it above the fuel pipe in plan view, the patent enables a compact three-dimensional layout that shortens the downstream portion length. This reduction in length prevents gas backflow from the engine to the downstream portion, thereby improving exhaust gas purification efficiency and fuel consumption.

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

3Length of stationary object

If the gear box overlaps the fuel pipe end in side view to shorten the downstream portion, then the throttle valve can be closer to the fuel injection device, but this may cause interference between the gear box and fuel pipe

Engineering Contradiction:
Improvedownstream portion lengthVSAvoidcomponent interference
Core Design Contradiction:
Length of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent resolves potential interference by utilizing the vertical dimension: the gear box is positioned above the fuel pipe in plan view while overlapping it in side view. This three-dimensional arrangement allows the components to occupy the same lateral space without physical contact, enabling the downstream portion to be shortened while avoiding component interference.

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

Solution Approach 2:

The gear box and fuel pipe are arranged in a nested spatial configuration where the gear box is positioned above and overlaps the fuel pipe end. This nesting arrangement allows one component to be spatially contained within the projection of the other without physical interference, achieving compact layout while preventing harmful interactions.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4574639B1Straddled vehicle
Publication Date: 2026.04.08 YAMAHA MOTOR CO LTD
  • EP4574639B1 patent drawingFigure 1
  • EP4574639B1 patent drawingFigure 2
  • EP4574639B1 patent drawingFigure 3

AI summary

A straddled vehicle (1) includes an engine (10), an intake pipe (41) connected to the engine (10), a throttle valve (52) provided in the intake pipe (41), a gear box (55) coupled to the throttle valve (52), a motor (58) coupled to the gear box (55) and driving the throttle valve (52) via the gear box (55), a fuel injection device (61) attached to a portion of the intake pipe (41) from the throttle valve (52) to the engine (10), and a fuel pipe (63). The fuel pipe (63) has a first end (64) connected to the fuel injection device (61). The gear box (55) overlaps the first end (64) in vehicle side view. The gear box (55) is disposed in one of a right area (AR) located rightward of the fuel injection device (61) and a left area (AL) located leftward of the fuel injection device (61). The first end (64) is disposed in the other of the right area (AR) and the left area (AL).