Power management of transportation refrigeration unit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Engineless transportation refrigeration units (TRU) struggle to maintain optimal box temperatures when the truck engine is off, as they lack a power source to regulate the temperature effectively.
Innovation Solution
A TRU controller electronically connected to the truck engine controller, which determines safety conditions, including fuel levels, to actuate the truck engine and draw power from it when necessary to maintain set-point temperatures, using components like a compressor, evaporator, and fan, and communicates via CAN bus to manage power efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the truck engine is turned off to reduce fuel consumption, then fuel efficiency improves, but the TRU cannot maintain the cargo box temperature within the acceptable range
Solution Approach 1:
The TRU system autonomously monitors cargo box temperature and automatically starts the truck engine when temperature deviations are detected, without requiring manual intervention. The system serves itself by self-diagnosing temperature issues and self-resolving them through engine actuation, thereby maintaining temperature control while minimizing unnecessary fuel consumption.
Solution Approach 2:
The system continuously monitors cargo box temperature and uses this feedback to determine when engine power is needed. The temperature sensor data feeds back to the control logic, which then decides whether to actuate the engine, creating a closed-loop control system that optimizes fuel consumption based on actual temperature conditions.
2Temperature
If the truck engine is started to power the TRU cooling system, then temperature regulation capability improves, but fuel consumption increases
Solution Approach 1:
Instead of running the engine continuously, the system uses periodic action by only starting the engine when temperature deviations are detected. The engine is actuated temporarily to correct temperature issues, then shut off when the cargo box temperature returns to the acceptable range, thereby reducing overall fuel consumption while maintaining temperature control capability.
Solution Approach 2:
The TRU system autonomously determines when engine power is needed and automatically actuates the engine only for the minimum necessary duration to correct temperature deviations. This self-service approach eliminates the need for continuous engine operation or manual intervention, optimizing fuel consumption while ensuring temperature regulation.
3Temperature
If manual monitoring and engine starting is used to maintain temperature, then temperature control is achieved, but human error and delayed response occur
Solution Approach 1:
The TRU system performs self-monitoring of cargo box temperature and automatically actuates the engine when temperature deviations are detected, eliminating the need for manual monitoring. This autonomous operation removes human error and delayed response entirely, as the system immediately detects and responds to temperature issues without human intervention.
Solution Approach 2:
The system uses continuous temperature monitoring with immediate feedback to the control logic, enabling real-time detection and response to temperature deviations. This closed-loop feedback mechanism ensures reliable temperature control by instantly reacting to temperature changes, unlike manual monitoring which is subject to human response delays and errors.
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
Ensures unbroken cold chains, reduces fuel consumption by only operating the truck engine when needed, and eliminates human error in temperature regulation, preventing food waste and maintaining set-point temperatures in engineless TRU systems.
Implementation Method 1
a refrigerant compressor
Implementation Method 2
an evaporator
Implementation Method 3
evaporator, a condenser
Implementation Method 4
a condenser
Implementation Method 5
a fan
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Disclosed is a transportation refrigeration unit (TRU 104) for conditioning air in a cargo box (106), the TRU including a TRU controller (108) that is electronically connected to a truck engine controller (170), wherein when a delta between a cargo box temperature and a cargo box set point temperature is greater than a predetermined threshold, the TRU controller actuates the truck engine (168) when the truck engine is off, and conditions air in the cargo box to return the cargo box temperature to the set point temperature.