Coupling Assembly for Multi-Axle Driveline Drag Reduction
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Solution Overview
Problem
Existing coupling assemblies for multi-driven axle vehicles experience undesirable power losses due to drag moments and friction, leading to higher fuel consumption compared to single-axle vehicles, as the disconnectable driveline components continue to rotate, causing inefficiencies.
Innovation Solution
A coupling assembly featuring an externally controllable friction coupling with a differential drive and a form-fitting clutch, allowing the driveline to be uncoupled, thereby reducing drag moments and friction losses by ensuring the propeller shaft and its components remain stationary when not in use, thereby optimizing torque transmission and reducing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the disconnectable driveline components remain connected to transmit torque to the second driving axle, then the vehicle can operate in multi-axle drive mode, but drag moments and friction losses increase leading to higher fuel consumption
Solution Approach 1:
The driveline is segmented into a permanently driven first driveline and an optionally connected second driveline. The coupling assembly divides the torque transmission path, allowing the second driveline to be disconnected from the propeller shaft when not needed, eliminating drag losses while preserving multi-axle capability when required.
Solution Approach 2:
The coupling assembly provides dynamic control of the driveline configuration, switching between connected and disconnected states based on driving conditions. This dynamic adjustment allows the system to adapt between single-axle and multi-axle drive modes, optimizing fuel consumption by disconnecting the second driveline when full power is not required.
2Reliability
If the friction coupling is kept closed to maintain torque transmission to the second driving axle, then continuous drive capability is ensured, but power losses due to friction increase
Solution Approach 1:
The friction coupling operates periodically, being closed only when torque transmission to the second driving axle is required and open when not needed. This periodic engagement eliminates continuous friction losses while ensuring reliability when multi-axle drive capability is actually utilized.
3Loss of energy
If the coupling assembly disconnects the second driving axle to reduce drag moments, then fuel consumption decreases, but the complexity of the coupling mechanism increases
Solution Approach 1:
The coupling assembly merges the friction coupling mechanism with the differential drive input, integrating torque control functionality into the existing driveline architecture. This consolidation reduces overall system complexity compared to separate coupling mechanisms while achieving the goal of reducing drag moments and fuel consumption.
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
The solution significantly reduces drag moments and friction losses, resulting in lower fuel consumption by allowing the driveline components to rotate freely when not transmitting torque, thereby enhancing the efficiency of multi-driven axle vehicles.
Implementation Method 1
an externally controllable friction coupling with a coupling input part (62) and a coupling output part (83)
Data Source
AI summary
A coupling assembly for optionally connecting a driving axle in a motor vehicle having multiple driving axles is disclosed. The coupling assembly comprises an externally controllable friction coupling with a coupling input part and an output part. The input part is rotatingly drivable around an axis of rotation A. A differential drive with an input element and two output elements which are drivingly connected to the input element, are also included. The input element of the differential drive is arranged coaxially relative to the coupling output part and drivably connected to the coupling output part for the purpose of transmitting torque. A driveline assembly having such a coupling assembly is also disclosed.