TRU Power Management With Battery Buffering for Variable Generator Speed
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Solution Overview
Problem
Existing transport refrigeration units (TRUs) rely on hydraulic mechanisms to maintain constant generator speed, leading to high costs and complexity, and there is a need for a more efficient and cost-effective power management system.
Innovation Solution
Mechanically connecting the generator to the engine via a power take-off and using a battery unit to supply power to the TRU dynamically, allowing the generator speed to vary with engine speed, and incorporating a clutch and power inverters to optimize power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydraulic mechanism is used to maintain constant generator speed, then the generator can provide stable electrical power to the TRU, but the system complexity and cost increase
Solution Approach 1:
The patent removes the hydraulic mechanism from the system entirely, extracting the complex speed-regulation component while retaining the essential function of powering the TRU. The generator is directly mechanically coupled to the engine, eliminating the intermediate hydraulic pump and motor system that previously regulated generator speed.
Solution Approach 2:
The system transitions from a static constant-speed configuration to a dynamic variable-speed configuration. The generator speed now varies with engine speed, and the battery unit dynamically adjusts its charging/discharging operations to compensate for power fluctuations, ensuring stable TRU operation without mechanical speed regulation.
2Reliability
If a hydraulic mechanism is used to maintain constant generator speed, then the generator can provide stable electrical power to the TRU, but the manufacturing and installation cost increase
Solution Approach 1:
The patent removes the hydraulic mechanism from the system entirely, extracting the complex speed-regulation component while retaining the essential function of powering the TRU. The generator is directly mechanically coupled to the engine, eliminating the intermediate hydraulic pump and motor system that previously regulated generator speed.
Solution Approach 2:
The system replaces expensive, complex hydraulic components with simpler, cheaper mechanical and electrical components. The direct mechanical coupling and battery-based power management represent a more cost-effective approach that reduces manufacturing, installation, and maintenance costs while achieving the same reliability outcome.
3Device complexity
If the generator is mechanically connected to the engine, then the system complexity is reduced, but the generator speed varies with engine speed affecting power stability
Solution Approach 1:
The battery unit serves as an intermediary energy storage device between the variable-speed generator and the TRU. It absorbs power fluctuations from the generator during charging and provides stable power during discharging, mediating the connection between the simple mechanical drive system and the power-sensitive TRU load.
Solution Approach 2:
The system changes the operational parameters of the generator, allowing it to operate across a variable speed range rather than maintaining a fixed speed. The battery unit compensates for these parameter variations, enabling the generator to efficiently operate at different speeds while maintaining stable TRU power supply.
4Use of energy by moving object
If the generator operates at varying speeds, then fuel efficiency is improved during acceleration, but the electrical power output becomes less stable
Solution Approach 1:
The battery unit performs preliminary energy storage during periods when the generator produces excess power (such as during steady-state cruising), preparing stored energy for later use during acceleration or high-demand periods. This preliminary charging action ensures power stability is maintained while allowing the generator to operate at fuel-efficient varying speeds.
Solution Approach 2:
The system changes the operational parameters of the generator, allowing it to operate across a variable speed range rather than maintaining a fixed speed. The battery unit compensates for these parameter variations, enabling the generator to efficiently operate at different speeds while maintaining stable TRU power supply.
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
Reduces manufacturing and maintenance costs, improves fuel efficiency by decoupling the generator during acceleration and braking, and ensures reliable power to the TRU, maintaining optimal conditions for transported goods.
Implementation Method 1
a generator mechanically connected to the engine, the generator being configured to be mechanically driven by the engine and to supply electrical power to the battery unit
Data Source
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AI summary
A vehicle for transporting goods and a method of powering a transport refrigeration unit are described. The vehicle (100) comprises a transport refrigeration unit (150); an engine (110); and a power management system (200; 300; 400). The power management system comprises: a battery unit (240; 340; 440) electrically connected to the transport refrigeration unit (150); and a generator (230; 330; 430) mechanically driven by the engine (110) to supply electrical power to the battery unit (240; 340; 440). The power management system (200; 300; 400) is configured to supply electrical power responsive to a power demand of the transport refrigeration unit (150). In this way, the power demand of the transport refrigeration unit (150) may always be met even if the generator (230; 330; 430) does not generate enough electrical power to meet the power demand of the transport refrigeration unit (150).