Cabin CO2 Alert Control Under Low Battery Conditions
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Solution Overview
Problem
Existing systems using CO2 refrigerants in vehicles fail to adequately alert occupants of impending power shortages due to insufficient battery charge, leading to potential excessive CO2 concentration increases when the ignition is off.
Innovation Solution
A vehicle system that includes a CO2 sensor, occupant sensor, generator, battery, and controller to alert occupants of impending power shortages by varying alert levels based on CO2 concentration and battery charge, without necessarily performing forced ventilation when the ignition is off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the blower is constantly operated to forcibly ventilate the vehicle cabin when CO2 concentration exceeds a reference value, then the CO2 concentration can be suppressed from being excessively high, but electric power may be insufficient before CO2 is sufficiently discharged when the remaining charge level of the battery is low
Solution Approach 1:
The system dynamically adjusts the blower operation mode based on real-time battery charge level detection. When charge level is sufficient, forced ventilation is activated; when charge level is low, natural ventilation is permitted. This dynamic adaptation resolves the contradiction between maintaining CO2 control reliability and managing electric power consumption effectively.
Solution Approach 2:
The controller changes the operational parameters of the air conditioner system based on the detected battery charge level. By switching between forced ventilation mode (high power consumption) and natural ventilation mode (low power consumption) according to charge level thresholds, the system optimizes the balance between CO2 concentration control and power conservation.
2Reliability
If the blower is operated in outside air circulation mode to forcibly ventilate the vehicle interior, then CO2 can be discharged to the outside of the vehicle, but the occupant cannot predict the power shortage and take appropriate action
Solution Approach 1:
The system implements a feedback mechanism where the controller continuously monitors battery charge level and provides information feedback to the occupant through alert outputs. When the charge level falls below a predetermined threshold, the controller alerts the occupant about impending power shortage, enabling timely action while maintaining effective CO2 discharge operations.
Solution Approach 2:
The controller performs preliminary alerting about power shortage conditions before actual power depletion occurs. By detecting low charge levels in advance and notifying the occupant, the system enables preliminary actions (such as seeking alternative power sources or preparing for shutdown) while still maintaining CO2 discharge effectiveness during the alert period.
3Reliability
If forced ventilation is performed when the remaining charge level of the battery is lower than a predetermined reference charge level, then CO2 concentration can be reduced, but power consumption increases and may deplete the battery before CO2 is sufficiently discharged
Solution Approach 1:
Instead of constantly operating the blower at full capacity, the system applies partial action by operating the blower only when necessary (when CO2 exceeds reference value and charge level is sufficient). This selective operation reduces overall energy loss while still achieving adequate CO2 concentration suppression during critical periods.
Solution Approach 2:
The system cushions against future energy depletion by monitoring battery charge level in advance and adjusting blower operation accordingly. When charge level is low, the system reduces or suspends forced ventilation to preserve remaining battery charge, preventing complete power depletion before CO2 discharge is completed.
Data Source
AI summary
The vehicle includes a generator, an air conditioner for circulating a CO2 coolant, a battery for supplying power to an auxiliary machine including the air conditioner, a CO2 sensor, an occupant sensor for detecting the presence or absence of an occupant, and a controller, wherein the controller outputs a warning to the occupant without performing forced ventilation by the air conditioner when an ignition switch of the vehicle is off and an occupant is detected by the occupant sensor, and a detected concentration by CO2 sensor exceeds a prescribed allowable concentration and a remaining charge level of the battery is less than a prescribed reference charge amount.