Device and method for controlling operation of transport refrigeration unit
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Solution Overview
Problem
Transport refrigeration units (TRUs) with only two operation modes (low speed and high speed) cannot optimize fuel consumption in real-world applications, leading to inefficient temperature control and high engine operation hours, which affects fuel efficiency and the resale value of the units.
Innovation Solution
A controller device with a processor and non-transitory computer-readable medium that regulates the compressor to operate in a continuously-variable speed mode, allowing for smooth gradient range of speed variations, enabling multiple operating stages such as start-stop, cycle-sentry, and continuous run, and allowing the compressor to operate at speeds greater than the engine's range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the compressor operates in discrete low speed and high speed modes only, then the device complexity is reduced, but the fuel efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning the compressor from static discrete speed modes to dynamic continuous variable speed operation. The controller enables the compressor to operate at any speed within a continuous range, allowing real-time adaptation to cooling demands and optimizing fuel efficiency across varying operating conditions.
Solution Approach 2:
The patent implements parameter changes by modifying the compressor speed parameter from discrete fixed values to continuous variable values. This allows the system to adjust the compressor speed parameter continuously based on temperature differential, ambient conditions, and cooling load, thereby optimizing fuel consumption.
2Use of energy by moving object
If the compressor operates at lowest engine speed continuously, then the fuel efficiency is improved, but the temperature control time increases
Solution Approach 1:
The system dynamically adjusts compressor speed based on real-time temperature differential between the transport unit interior and exterior. When a large temperature differential exists, the compressor operates at higher speeds to rapidly reduce the differential. When the differential is small, the compressor operates at lower speeds to maintain temperature efficiently, thus optimizing both time and fuel consumption.
Solution Approach 2:
The controller implements periodic monitoring of temperature conditions and adjusts compressor speed accordingly. The system cycles through different speed levels based on whether pull-down or pull-up conditions exist, optimizing the balance between rapid temperature control and fuel efficiency.
3Productivity
If the compressor operates at highest engine speed, then the temperature control speed is improved, but the fuel consumption increases
Solution Approach 1:
The system applies partial action by operating the compressor at high speed only when necessary during pull-down or pull-up conditions. Once the temperature differential is reduced to acceptable levels, the compressor speed is reduced to lower levels for maintenance operation, avoiding excessive fuel consumption while still achieving rapid temperature control when needed.
Solution Approach 2:
The controller periodically assesses whether high-speed operation is necessary based on temperature differential thresholds. High speed operation is activated temporarily during pull-down/pull-up events and then deactivated when temperature control is achieved, creating a periodic pattern of high and low speed operation that balances productivity and fuel efficiency.
4Reliability
If the engine operates at highest speed frequently, then the temperature control effectiveness is improved, but the resale value deteriorates
Solution Approach 1:
The system dynamically adjusts engine speed based on actual cooling requirements rather than operating at fixed high speed. By matching engine speed to the instantaneous temperature differential and cooling load, the system achieves effective temperature control while minimizing total engine operation hours, thereby preserving resale value.
Solution Approach 2:
The controller changes the engine speed parameter from fixed high speed to variable speed based on operating conditions. This parameter adjustment allows the system to achieve temperature control effectiveness when needed while reducing cumulative engine hours through lower speed operation during maintenance phases.
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 solution improves fuel efficiency by 10-20% by optimizing compressor speed based on temperature changes, reducing engine operation hours, and maintaining desired temperatures efficiently, thus enhancing the operational effectiveness of TRUs.
Implementation Method 1
The TRU includes a compressor (108)
Implementation Method 2
The TRU is attached to the TU to facilitate a heat exchange between the air inside the cargo space and the air outside of the TU
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A transport refrigeration unit (102) and a method for controlling the transport refrigeration unit (102), wherein the transport refrigeration unit (102) has a controller device (110; 200) for operating a compressor (108) of the transport refrigeration unit (110) with a continuously-variable speed, which allows the compressor (108) to run continuously but with a smooth gradient range of speed variations. The controller device (110; 200) allows the transport refrigeration unit (102) to have a start-stop operation stage, continuous run operation stage, and/or a cycle-sentry operation stage.