Dolly Vehicle Propulsion with Dual Motors for Wide-Speed Torque
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Solution Overview
Problem
Existing self-powered dolly vehicles face challenges in generating sufficient torque across a wide range of vehicle speeds, from standstill to highway cruising, which affects their startability and overall performance in cargo transport scenarios.
Innovation Solution
A propulsion arrangement featuring two electric machines with different gear ratios, one fixed and one configurable, connected via a gearbox and open differential, allowing for adaptable torque generation and regenerative braking, optimized by a control unit that adjusts gear ratios based on vehicle speed and axle speed sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electric machine with fixed gear ratio is used, then the device complexity is reduced, but the adaptability to different vehicle speeds and torque requirements deteriorates
Solution Approach 1:
The propulsion arrangement is segmented into two separate electric machines (first and second electric machines) with different gear ratios, allowing each machine to be optimized for specific speed ranges. This segmentation enables the system to handle both low-speed high-torque scenarios and high-speed cruising efficiently, resolving the contradiction between device complexity and adaptability.
Solution Approach 2:
The system dynamically switches between different electric machines and gear ratios based on vehicle speed and torque requirements. The configurable gear ratio of the second electric machine can be adjusted in dependence of driving scenario, vehicle speed, and electric machine axle speed, providing dynamic adaptability while maintaining manageable complexity through automated control.
2Adaptability or versatility
If multiple electric machines with configurable gear ratios are used, then the adaptability to different driving scenarios is improved, but the device complexity increases
Solution Approach 1:
The control unit continuously monitors vehicle speed, electric machine axle speed, and driving scenario conditions, then adjusts the configurable gear ratio of the second electric machine accordingly. This feedback mechanism enables automated optimization of the propulsion arrangement, improving adaptability while keeping the control system manageable through sensor-based decision making.
3Productivity
If gear switching is implemented for the second electric machine, then the productivity across different speed ranges is improved, but the device complexity increases
Solution Approach 1:
The system changes the gear ratio parameter of the second electric machine based on operating conditions. The configurable gear ratio can be selected between different ratios in dependence of the driving scenario, vehicle speed, and electric machine axle speed, allowing the system to optimize productivity across different speed ranges while maintaining a relatively simple control structure through parameter adjustment rather than mechanical complexity.
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 enhances the dolly vehicle's ability to support both starting from standstill and high-speed cruising, improving overall performance and fuel efficiency by optimizing torque delivery across various driving scenarios.
Implementation Method 1
a first electric machine, a second electric machine, a gearbox, and an open differential for driving first and second wheels of a driven axle
Implementation Method 2
connected to the open differential via the gearbox at respective gear ratios
Implementation Method 3
open differential for driving first and second wheels of a driven axle
Data Source
AI summary
A propulsion arrangement for a self-powered dolly vehicle unit, the propulsion arrangement comprising a first electric machine, a second electric machine, a gearbox, and an open differential for driving first and second wheels of a driven axle, wherein the first and second electric machines are arranged in parallel and connected to the open differential via the gearbox at respective gear ratios.