Split Powertrain Axle Weight Distribution
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Solution Overview
Problem
Heavy vehicles face issues with front axle load increase due to engine and gearbox weight distribution, leading to tire wear, reduced traction, and steering difficulties, as well as cooling and noise emission challenges, especially in densely packaged engine compartments and short wheelbase designs.
Innovation Solution
The engine and gearbox are arranged on either side of the driven axle, separated by a power transmitting device, allowing for better weight distribution, reduced steering forces, improved cooling, and noise reduction, with options for propeller shaft, hydraulic, or electric motor/pump configurations to enhance flexibility and design space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the engine and gearbox are placed together above the front axle, then the power transmission is simplified, but the front axle load increases excessively
Solution Approach 1:
The patent divides the traditionally combined engine-gearbox package into separate units. The engine is placed above the front axle while the gearbox is positioned above the rear axle, connected via a propeller shaft. This segmentation allows the heavy engine to contribute to front axle load (improving steering stability) while the gearbox weight is distributed to the rear axle, preventing excessive front axle loading.
2Weight of moving object
If the engine and gearbox are separated and placed on opposite sides of the driven axle, then the front axle load is reduced, but the power transmission system becomes more complex
Solution Approach 1:
The patent introduces a propeller shaft as an intermediary power transmission element connecting the engine above the front axle to the gearbox above the rear axle. This intermediary component enables the separation of engine and gearbox into optimal positions for weight distribution while maintaining efficient power transmission, avoiding the need for overly complex alternative transmission systems.
3Length of moving object
If the wheelbase is shortened, then the vehicle dimensions are improved, but the propeller shaft angle difference increases
Solution Approach 1:
The patent employs a dynamically adjustable propeller shaft system that can accommodate varying angles through telescopic sections and universal joints. This dynamic design allows the propeller shaft to adapt to the increased angle differences caused by shorter wheelbases, maintaining effective power transmission while enabling more compact vehicle dimensions.
4Volume of moving object
If the engine compartment is densely packaged, then the space utilization is improved, but the cooling system complexity increases
Solution Approach 1:
The patent extracts the gearbox from the traditional engine compartment location and positions it above the rear axle. This extraction creates additional space in the engine compartment for optimized engine cooling system design, allowing for better air flow and cooler placement without compromising overall vehicle space utilization. The gearbox is separately cooled in its new position.
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 arrangement reduces front axle load, improves traction and steering, eliminates the need for special gearbox cooling, and decreases noise emissions, while allowing for shorter wheelbases and more efficient cargo loading and unloading.
Implementation Method 1
The driving power is transmitted via a propeller shaft system to one or several driven rear axles
Implementation Method 2
the vibration level from the engines tends to increase due to, amongst other things, different development steps taken for dealing with the demands coming from new exhaust emission legislation
Data Source
AI summary
A vehicle includes a front axle and rear axle, where at least one of said axles is driven, an engine arranged in the vicinity of the rear or front end of said vehicle, the engine including an output shaft connected to the driven axle via a transmission system for transmitting driving power from the engine to the driven axle. The transmission system includes at least a multiple-speed gearbox for causing variable gear ratio between the engine and driven axle. The engine and at least a part of the gearbox are arranged on each side of the driven axle, and are connected only via a power transmitting device so that an engine block of the engine is separated from a gearbox housing of the gearbox.