Off-Road Vehicle Engine Layout for Heat and Comfort Balance

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Solution Overview

Problem

Off-road vehicles face challenges in balancing compactness and user comfort due to the positioning of the engine cylinder head adjacent to the front, leading to higher temperatures near the driver and difficulties in seat arrangement, which affects the center of gravity and driving experience.

Innovation Solution

The engine cylinder head is positioned mid-way in the vehicle's front-rear direction relative to the wheel rotation axes, with a button assembly to control the differential mechanism, enhancing safety and reducing user operation difficulty, and the exhaust assembly is positioned to avoid overheating the driver's area, while the intake assembly is designed for easy filter replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the engine cylinder head is arranged adjacent to the front of the vehicle, then the exhaust pipe and muffler can be positioned, but the temperature near the driver's body increases and driving comfort deteriorates

Engineering Contradiction:
Improvetemperature near driver's bodyVSAvoiddriving comfort
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The patent repositions the cylinder head from a front-adjacent location to a mid-vehicle location along the front-rear axis. Specifically, the cylinder head midpoint is positioned between the front rotation axis of the front wheel and the rear rotation axis of the rear wheel, with the exhaust port facing the rear end. This dimensional repositioning in the longitudinal axis allows the exhaust system to terminate at the rear of the vehicle, moving the heat source away from the driver's lower body and improving thermal comfort while maintaining exhaust functionality.

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

2Ease of operation

If the engine position is adjusted to improve comfort, then temperature distribution improves, but seat arrangement and center of gravity become difficult to balance

Engineering Contradiction:
Improvedriving comfortVSAvoidcenter of gravity
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent optimizes the longitudinal position of the cylinder head within the mid-vehicle range, adjusting parameters such as the distance from the front rotation axis and rear rotation axis to achieve an optimal balance between driver comfort and vehicle stability. The exhaust port is positioned to face the rear end, which helps in achieving a reasonable center of gravity while maintaining comfortable temperature distribution in the driver area.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the exhaust port faces the rear end of the frame, then exhaust performance improves, but the exhaust assembly configuration becomes more complex

Engineering Contradiction:
Improveexhaust performanceVSAvoidexhaust assembly configuration
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The cylinder head is designed with an exhaust port that faces the rear end of the frame, allowing the exhaust system to serve multiple functions: efficient exhaust gas discharge, rearward heat dissipation away from the driver, and integration with the vehicle's rear structure. This multi-functional design improves exhaust performance while the exhaust assembly is configured to manage the complexity through strategic component placement.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4393738B1Off-road vehicle
Publication Date: 2025.07.09 ZHEJIANG CFMOTO POWER CO LTD
  • EP4393738B1 patent drawingFigure 1
  • EP4393738B1 patent drawingFigure 2a
  • EP4393738B1 patent drawingFigure 2b

AI summary

An off-road vehicle includes a frame, a plurality of wheels, and a transmission system. A front transmission assembly rotates around a front rotation shaft. A rear transmission assembly rotates around the rear rotation shaft. A straight line, L1 is defined as a straight line connecting a projection point of the cylinder head mid-point projected on the longitudinal mid-plane and a projection point of an axis of the front rotation shaft projected on the longitudinal mid-plane. A straight line, L2 is defined as a straight line connecting a projection point of the cylinder head mid-point projected on the longitudinal mid-plane and a projection point of an axis of the rear rotation shaft projected on the longitudinal mid-plane. A ratio of the length of L1 and the length of L2 is in the range from 0.4 to 1.8. The off-road vehicle has a compact structure and better comfort riding comfort.