Vehicle Refrigeration Failure Control Using Heat Exchanger Power Limiting
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Solution Overview
Problem
Refrigeration systems in vehicles, particularly Purpose Built Vehicles (PBVs), face challenges in maintaining temperature control when they malfunction during operation, leading to potential damage of temperature-sensitive cargo and incurring significant economic and time losses.
Innovation Solution
A method and device for controlling refrigeration systems that detect failures, utilize a current consumption map to determine an in-failure operating current amount, and switch the operation mode to limit power usage in the heat exchanger, ensuring continued temperature control and minimizing damage to cargo.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refrigeration system operates in normal mode with full power to the heat exchanger, then the temperature control performance is optimal, but the system cannot operate during failure conditions without causing cargo damage
Solution Approach 1:
The patent implements dynamic operation mode switching that adapts the heat exchanger power based on system status. During normal operation, the system operates in normal mode with full power. When failure is detected, it dynamically transitions to in-failure operation mode, adjusting the power to the heat exchanger to a limited level that prevents cargo damage while acknowledging the failure condition. This dynamic adaptation resolves the contradiction between maintaining reliability during failure and preserving temperature control stability.
Solution Approach 2:
The patent changes the operating parameters of the refrigeration system based on failure detection. Specifically, it modifies the power supply parameters to the heat exchanger by switching between normal operation mode (full power) and in-failure operation mode (limited power). This parameter change allows the system to maintain reliability during failure conditions while accepting a modified temperature control profile that prevents cargo damage.
2Productivity
If the system switches to in-failure operation mode with limited power to the heat exchanger, then the system can continue operating during failure, but the power consumption is reduced which may affect temperature maintenance
Solution Approach 1:
The patent applies partial action by providing only the necessary amount of power to the heat exchanger during failure conditions, rather than full power. The in-failure operation mode delivers limited power that is sufficient to prevent cargo damage and maintain basic temperature control, but does not attempt to achieve optimal temperature maintenance. This partial power delivery enables continuous operation during failure while being energy-efficient.
Solution Approach 2:
The system automatically detects failure conditions and self-adjusts its power consumption by switching to in-failure operation mode. The controller monitors system status and autonomously determines when to reduce power to the heat exchanger, enabling the system to serve itself during failure conditions without external intervention. This self-service capability ensures continuous operation while adapting power consumption to actual needs.
3Object-affected harmful factors
If the system detects failure and switches operation mode, then cargo damage is prevented, but the system complexity increases with additional control logic
Solution Approach 1:
The patent implements a universal control approach where a single controller handles both normal operation and in-failure operation modes. The same controller that manages normal refrigeration operations also detects failures and executes the mode switching to in-failure operation. This multi-functionality prevents cargo damage while avoiding the need for separate dedicated failure management hardware, thus limiting the increase in system complexity.
Solution Approach 2:
The system prepares for failure conditions by having the in-failure operation mode ready and configured in advance. The controller is pre-programmed with the failure detection logic and the corresponding response actions. When failure occurs, the system can immediately switch to the pre-prepared in-failure mode without needing to develop a response in real-time, thereby preventing cargo damage while keeping the control logic manageable through advance preparation.
Data Source
AI summary
A method for controlling a refrigeration system of a vehicle, which controls a freezer controlling a temperature of a freezing room when the refrigeration system installed in the vehicle malfunctions, includes: detecting a failure of the refrigeration system; receiving a predefined current consumption map for the refrigeration system; when a failure of the refrigeration system is detected, calculating an in-failure operating current amount for controlling an operation of the freezer during a failure based on a current consumption derived from the current consumption map; and transmitting both the in-failure operating current amount and an operating command of the freezer to a power supply device of the freezer to switch an operation mode of the refrigeration system from a normal operation mode to an in-failure operation mode so that the power supply device limits power used in a heat exchanger. A device may be configured to perform the method.