Transport Refrigeration Engine Load Control for Mode-Change Stability
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Solution Overview
Problem
Transport refrigeration systems (TRS) face challenges in managing power source loading during operational mode changes, leading to potential overloading beyond predefined revolutions per minute (RPM) bandwidths and power limits, which can violate regulatory requirements and affect efficient climate control in multi-zone transport units.
Innovation Solution
A method and system that utilize a controller to identify operational mode changes in heat exchanger units, perform load control actions such as adjusting refrigerant flow, fan speeds, and engine speeds to prevent power source overloading, ensuring the power source remains within a predefined RPM band and power limit, and revert to original settings after the mode change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the heat exchanger unit changes operational mode rapidly to respond to climate control demands, then the responsiveness and climate control efficiency are improved, but the power source may exceed predefined RPM bandwidth and power limits, causing overloading
Solution Approach 1:
The controller performs preliminary assessment of power source capacity before initiating operational mode changes. It calculates the future load on the power source and determines appropriate load control actions in advance, preventing overloading before it occurs by preparing the system proactively
Solution Approach 2:
The controller continuously monitors system parameters including power source load, RPM, and temperature conditions. Based on this feedback, it dynamically adjusts load control actions during operational mode transitions, ensuring the power source remains within predefined RPM bandwidth and power limits while maintaining climate control effectiveness
2Reliability
If load control actions are performed to prevent power source overloading, then the power source remains within operational limits, but the system complexity and control mechanisms increase
Solution Approach 1:
The controller performs multiple functions including identifying operational mode change requests, assessing power source capacity, determining load control actions, and managing heat exchanger unit operations. By consolidating these diverse control functions into a single multi-functional controller, the patent avoids the need for separate dedicated control devices for each function, thereby limiting the increase in system complexity
3Reliability
If the system maintains strict power limit compliance during operational mode changes, then regulatory requirements are met, but the climate control responsiveness and efficiency may be reduced
Solution Approach 1:
The controller dynamically adjusts load control actions based on real-time system conditions, power source capacity assessment, and predicted future load. This dynamic approach allows the system to optimize climate control efficiency within regulatory limits by adapting control strategies to current operational needs rather than applying fixed conservative restrictions
Data Source
AI summary
Methods and systems for controlling a transport refrigeration system are provided. In one instance, the method includes identifying an operational mode change request for a heat exchanger unit of the transport refrigeration system. The method also includes preparing the transport refrigeration system for the operational mode change of the heat exchanger unit, wherein preparing the transport refrigeration system for the operational mode change of the heat exchanger unit includes performing a load control action, the load control action preventing a power source of the transport refrigeration system from at least one of operating outside of a predefined revolutions per minute (RPM) bandwidth and exceeding a predefined power limit of the power source. Also, the method includes changing the operational mode of the heat exchanger unit; and removing the load control action.