Engine Cylinder Head Fastener Height Configuration

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Solution Overview

Problem

Existing engine designs face challenges in improving accessibility to valve shaft ends while minimizing engine size, and in avoiding interference between fastening bolts and the head cover, which often results in increased engine size.

Innovation Solution

The engine design incorporates a configuration where the cylinder head and head cover engaging surfaces are arranged to overlap with the camshaft, with inclined inner surfaces of the cover walls and strategically positioned fastening bolts to maintain clearance and reduce size, allowing for improved accessibility and rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the engaging surface of the cylinder head and head cover is arranged at the same height as the cam shaft, then accessibility to the shaft ends of the valves is improved, but the head section of the fastening bolt may interfere with the side surface of the head cover

Engineering Contradiction:
Improveaccessibility to shaft ends of valvesVSAvoidinterference between fastening bolt and head cover
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent positions the fastening bolts at different heights (first and second heights) rather than at the same level, utilizing the vertical dimension to resolve the interference problem while maintaining accessibility to valve shaft ends

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

Solution Approach 2:

The patent divides the fastening system into multiple fastening bolts positioned at different heights, with the first fastening bolt at a first height and the second fastening bolt at a second height, allowing each bolt to serve its function without interference

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If a large distance is secured between the fastening bolt and the side surface of the head cover to avoid interference, then interference is prevented, but the size of the engine increases

Engineering Contradiction:
Improveinterference between fastening bolt and head coverVSAvoidsize of engine
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

Instead of increasing horizontal distance, the patent utilizes the vertical dimension by positioning fastening bolts at different heights, thereby preventing interference without increasing engine width or volume

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

Solution Approach 2:

The patent changes the vertical position parameter of the fastening bolts, arranging them at different heights relative to the cam shaft and engaging surface, which prevents interference while maintaining compact engine dimensions

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If the first head section is arranged closer to the first cylinder side wall, then the size of the engine is reduced, but the distance between the first cover side wall and the first head section becomes shorter

Engineering Contradiction:
Improvesize of engineVSAvoiddistance between cover side wall and head section
Core Design Contradiction:
Volume of moving objectVSLength of moving object

Solution Approach 1:

The patent resolves the spatial conflict by utilizing the vertical dimension, positioning the first head section at a first height and the second head section at a second height, which allows compact horizontal arrangement while maintaining adequate vertical clearance

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

Data Source

PatentEP3130778B1engine
Publication Date: 2023.08.02 YAMAHA MOTOR CO LTD
  • EP3130778B1 patent drawingFigure 1
  • EP3130778B1 patent drawingFigure 2
  • EP3130778B1 patent drawingFigure 3

AI summary

A first head section is arranged between a first cylinder side wall and a second head section in the axial direction of a cam shaft. The second head section is arranged between a second cylinder side wall and the first head section in the axial direction of the cam shaft. The distance between the first cylinder side wall and the first head section in the axial direction of the cam shaft is shorter than the distance between the second cylinder side wall and the second head section in the axial direction of the cam shaft. The distance to the first head section in a cylinder axial direction from a third virtual plane, which includes the axis of a crank shaft and is perpendicular to a cylinder axis, is shorter than the distance to the second head section in the cylinder axial direction from the third virtual plane.