Smart Axle Gear Shifting and Power Divider Control
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Solution Overview
Problem
Existing drivetrain systems fail to fully exploit transmission efficiencies by correlating multiple ratio gearbox gear ratio selection directly with the disconnection of power dividers or inter-axle differentials, leading to suboptimal traction and fuel efficiency.
Innovation Solution
A Multiple Range Independently Disconnecting Smart Axle system that employs a control system to sequentially shift through high-efficiency gear ratios and independently manage power distribution between rear drive axles, optimizing gear train efficiency and traction based on conditions like acceleration, traction, and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the multiple ratio gearbox gear ratio selection is directly correlated with the disconnection of power dividers or inter-axle differentials, then the system structure is simplified and operation is easier, but transmission efficiency is not maximized and drivetrain losses increase
Solution Approach 1:
The control system is segmented into multiple independent control modules: a transmission control module that manages transmission gear selection, a multiple ratio gearbox control module that manages gearbox ratio selection, and a power divider control module that manages power distribution to drive axles. This segmentation allows each module to independently optimize its function, enabling the system to maximize transmission efficiency by coordinating gear ratio selection with power divider engagement without requiring a monolithic complex control architecture.
Solution Approach 2:
The system implements dynamic control where the multiple ratio gearbox sequentially shifts through high-efficiency gear ratios based on real-time operating conditions such as acceleration, traction, and speed requirements. The power dividers are dynamically engaged or disconnected independent of gearbox ratio changes, allowing the system to adapt continuously to varying drivetrain demands while maintaining optimal transmission efficiency at each operating point.
2Use of energy by moving object
If the multiple ratio gearbox shifts through gear ratios to lower engine speed, then fuel efficiency improves, but traction may be insufficient under acceleration or low-speed conditions
Solution Approach 1:
The control system performs preliminary action by proactively engaging power dividers before traction conditions deteriorate. When operating conditions indicate potential traction needs (such as during acceleration or low-speed maneuvers), the control system pre-engages the power dividers to ensure adequate traction is available, rather than waiting for slip or loss of traction to occur. This allows the system to maintain fuel efficiency through high gear ratios while ensuring traction reliability is preserved through anticipatory power distribution.
Solution Approach 2:
The system employs feedback control where sensors continuously monitor operating conditions including acceleration rates, wheel slip, traction surface conditions, and speed. This feedback information is fed to the control system which adjusts power divider engagement and multiple ratio gearbox shifting decisions in real-time. The feedback loop ensures that fuel efficiency is maximized through appropriate gear selection while traction reliability is maintained by detecting and responding to deteriorating traction conditions before they compromise vehicle performance.
Data Source
AI summary
A forward rear drive axle of a vehicle having at least two rear drive axles has a multiple ratio gearbox and a power divider or inter-axle differential that can be connected to or disconnected from the rearward rear drive axle, so that the vehicle can be operated in 6×4 mode or in 6×2 mode. A control system is connected to the transmission and to the multiple ratio gearbox, and is configured to shift the gearbox sequentially through its ratios when the transmission is within a subset of its gear ratios chosen to maximize use of transmission gears exhibiting higher gear train efficiency. The control system is further configured to control the use of 6×4 mode or 6×2 mode independently from the shifting of the multiple ratio gearbox.