Axle-Driven TRU Powertrain With Multi-Speed Gearbox Control
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Solution Overview
Problem
Existing power generation systems for transport refrigeration units in refrigerated vehicles are inefficient and increase fuel consumption, particularly when using electrical power sources like batteries charged by generators coupled to the trailer axle.
Innovation Solution
A power system with a multi-speed gearbox that dynamically adjusts gear ratios based on vehicle speed and energy storage device state-of-charge to maintain consistent electrical power output, balancing power generation with fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed-ratio gearbox is used to couple the axle to the generator, then the system structure is simple, but the electrical power generated varies significantly with vehicle speed, reducing reliability of TRU operation
Solution Approach 1:
The patent applies the dynamics principle by implementing a multi-speed gearbox with variable gear ratios instead of a fixed-ratio gearbox. The controller dynamically adjusts the gear ratio based on vehicle speed and battery state-of-charge, allowing the generator to operate within optimal speed ranges across varying vehicle speeds. This ensures reliable electrical power generation for TRU operation while adapting to changing operating conditions.
2Duration of action of moving object
If the generator is coupled to the axle to recharge the battery, then the battery can be recharged during transit, but fuel consumption of the tractor increases
Solution Approach 1:
The patent applies parameter changes by using a multi-speed gearbox to optimize the generator's operating parameters (speed and power output) based on vehicle speed and battery state-of-charge. The controller selects from multiple gear ratios to keep the generator within its optimal efficiency range, maximizing electrical power generation while minimizing the energy extracted from the tractor's motion, thereby reducing fuel consumption compared to fixed-ratio systems.
3Power
If a multi-speed gearbox is used to optimize power generation, then electrical power output remains consistent across vehicle speeds, but the system complexity increases
Solution Approach 1:
The multi-speed gearbox with controller dynamically adjusts gear ratios to maintain consistent electrical power output from the generator across varying vehicle speeds. By selecting appropriate gear ratios based on real-time vehicle speed and battery state-of-charge, the system ensures the generator operates within optimal speed ranges, delivering consistent power for battery charging and TRU operation despite external speed variations.
Solution Approach 2:
The system incorporates feedback control where the controller receives data about vehicle speed and battery state-of-charge, processes this information, and automatically selects the appropriate gear ratio from the multi-speed gearbox. This closed-loop feedback mechanism ensures optimal power generation is maintained while adapting to changing operating conditions, justifying the increased system complexity through improved performance.
4Power
If the generator operates at high rotational speed to maximize power output, then electrical power generation is high, but the generator may exceed operational limits at high vehicle speeds
Solution Approach 1:
The multi-speed gearbox enables dynamic adjustment of the generator's rotational speed by providing multiple gear ratios. At high vehicle speeds, the controller selects lower gear ratios to prevent the generator from exceeding its maximum operational speed limits, while at lower vehicle speeds, higher gear ratios are selected to maximize power generation within the generator's optimal operating range. This dynamic adaptation ensures both high power output and operational reliability.
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 system efficiently powers transport refrigeration units across a wide range of vehicle speeds while reducing fuel consumption by optimizing generator output and battery charging, extending operation time between recharges.
Implementation Method 1
a generator configured to generate electrical power and to supply the electrical power to the energy storage device
Data Source
AI summary
A vehicle for transporting goods and a method of operating a power system of the vehicle are described. The vehicle comprises an axle; transport refrigeration unit; and power system. The power system comprises an energy storage device; a generator to generate electrical power and to supply electrical power to the energy storage device; a multi-speed gearbox mechanically coupling the axle to the generator; and a controller to receive data indicative of a speed of the vehicle and a state-of-charge of the energy storage device, and to control the multi-speed gearbox. The controller is configured to set a gear ratio of the multi-speed gearbox to a speed-based gear ratio when the vehicle is in a first state, wherein the speed-based gear ratio is selected based on the speed of the vehicle, and wherein the state-of-charge of the energy storage device is below a first charge threshold in the first state.