Compact Engine Unit Layout via Fore-Aft Exhaust Spacing

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Solution Overview

Problem

The existing saddle riding vehicles with a unit swing engine, catalyst unit, and exhaust gas sensor tend to increase in size vertically due to their disposition, making them less compact.

Innovation Solution

The saddle riding vehicle design includes a unit swing engine with a crankcase and cylinder portion extending in the fore-aft direction, a radiator beside the crankcase, an exhaust pipe connected to the cylinder portion with a catalyst unit and exhaust gas sensor spaced apart in the fore-aft direction, allowing for compact vertical disposition by utilizing the space inferior to the cylinder portion and optimizing the placement of the radiator, catalyst unit, and exhaust gas sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the catalyst unit and exhaust gas sensor are disposed inferior to the radiator, then the engine unit can be compactly arranged, but the vehicle size increases in the vertical direction

Engineering Contradiction:
Improveengine unit compactnessVSAvoidvehicle vertical size
Core Design Contradiction:
Volume of moving objectVSLength of stationary object

Solution Approach 1:

The patent transitions from vertical stacking (inferior to radiator) to horizontal fore-aft arrangement (anterior/posterior to crankcase), utilizing the fore-aft dimension to accommodate the catalyst unit and exhaust gas sensor without increasing vertical height. This dimensional shift resolves the contradiction by maintaining compact engine unit volume while reducing vehicle vertical size.

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

2Length of stationary object

If the catalyst unit and exhaust gas sensor are spaced apart in the fore-aft direction, then vertical space is optimized, but the exhaust pipe routing becomes more complex

Engineering Contradiction:
Improvevehicle vertical sizeVSAvoidexhaust pipe structure
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The exhaust pipe is divided into multiple segments: a first exhaust pipe connecting the cylinder to the catalyst unit, and a second exhaust pipe connecting the catalyst unit to the exhaust gas sensor. This segmentation allows each pipe section to be optimized independently for its specific function and spatial requirements, managing the complexity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the exhaust system are positioned at different fore-aft locations to optimize local space utilization. The catalyst unit is placed anterior to the crankcase while the exhaust gas sensor is positioned posterior to it, creating locally optimized arrangements that reduce overall vertical size without requiring uniformly complex routing throughout the entire exhaust system.

Inventive Principle:
Principle #3Local quality

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 enables a compact vertical arrangement of the catalyst unit, exhaust gas sensor, and radiator, improving the overall space efficiency and functionality of the engine unit within the vehicle.

Implementation Method 1

a catalyst unit (121) disposed in the exhaust pipe (77)

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

an exhaust gas sensor (141, 341) disposed in the exhaust pipe (77)

Methodology Applied
Scientific EffectGas detection:

Implementation Method 3

a radiator (60) disposed beside the crankcase (43)

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP3524785B1Saddle riding vehicle
Publication Date: 2021.05.26 HONDA MOTOR CO LTD
  • EP3524785B1 patent drawingFigure 1
  • EP3524785B1 patent drawingFigure 2
  • EP3524785B1 patent drawingFigure 3

AI summary

[Object] To enable an engine unit including a unit swing engine, a catalyst unit, and an exhaust gas sensor to be built compactly in a saddle riding vehicle. [Solving Means] A saddle riding vehicle includes: a unit swing engine 13 that includes a crankcase 43 and a cylinder portion 44 having a cylinder axis extending from the crankcase 43 in a vehicle fore-aft direction and that is swingably supported on a vehicle body frame 12; a radiator 60 disposed beside the crankcase 43; an exhaust pipe 77 connected with the cylinder portion 44; a catalyst unit 121 disposed in the exhaust pipe 77; and an exhaust gas sensor 141 disposed in the exhaust pipe 77. In the saddle riding vehicle, the catalyst unit 121 and the exhaust gas sensor 141 are spaced apart, in a side view, from each other in the vehicle fore-aft direction with respect to the radiator 60.