Vehicle Cabin Air Recirculation Control for CO2 and Energy Balance
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Solution Overview
Problem
Vehicle air conditioning systems are energy inefficient due to continuous reliance on external air for cooling, leading to excessive energy consumption and increased carbon dioxide levels within the cabin, which can cause driver fatigue and safety issues.
Innovation Solution
A method that measures carbon dioxide and humidity levels, along with cabin temperature, to calculate the optimal recirculation rate of air, minimizing outside air intake while maintaining safe and comfortable cabin conditions, using sensors and a processing unit to adjust the air-circulation and -recirculation system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If outside air is continuously provided to the cabin, then carbon dioxide levels are maintained at safe levels, but energy consumption increases significantly
Solution Approach 1:
The system dynamically adjusts the recirculation rate based on real-time carbon dioxide sensor readings. When CO2 levels are low, the system increases recirculation to save energy. When CO2 levels approach thresholds, the system increases fresh air intake. This dynamic adjustment resolves the contradiction by making the air supply strategy adaptive rather than static.
Solution Approach 2:
The system uses carbon dioxide sensors to continuously monitor cabin air quality and provides feedback to the HVAC control system. This feedback loop enables the system to automatically adjust the balance between recirculated and fresh air based on actual CO2 levels, resolving the contradiction through closed-loop control rather than open-loop fixed settings.
2Use of energy by moving object
If air recirculation is increased to minimize energy expenditure, then energy efficiency improves, but carbon dioxide concentration rises excessively
Solution Approach 1:
Carbon dioxide sensors provide continuous feedback on cabin air quality, enabling the control system to detect when CO2 levels are rising due to excessive recirculation. The system responds by automatically increasing fresh air intake to maintain safe CO2 levels while minimizing energy consumption, thus resolving the contradiction through real-time monitoring and adjustment.
Solution Approach 2:
The system transitions from static recirculation settings to dynamic adjustment based on actual cabin conditions. The recirculation rate is continuously optimized based on CO2 sensor readings, allowing the system to maximize energy efficiency while preventing harmful CO2 accumulation through adaptive control.
3Reliability
If excessive outside air is provided to minimize carbon dioxide concentration, then safety is improved, but energy cost increases significantly
Solution Approach 1:
Instead of providing excessive outside air continuously, the system applies partial action by introducing fresh air only when and to the extent needed to maintain safe CO2 levels. The recirculation rate is adjusted partially based on actual sensor readings, avoiding the energy waste of continuous excessive ventilation while maintaining safety through targeted intervention.
Solution Approach 2:
The system changes the operational parameters of the HVAC system based on real-time CO2 measurements. Rather than maintaining a fixed high fresh air intake rate, the system dynamically modifies the fresh air to recirculated air ratio parameter, optimizing the balance between safety and energy efficiency through parameter adaptation.
Data Source
AI summary
Method for optimizing energy use in vehicles comprising an air-circulation and -recirculation system, the method comprising the steps of measuring a carbon dioxide level of vehicle cabin air, a relative humidity level of cabin air and at least one temperature of at least one window, providing the measured carbon dioxide level, the relative humidity level and the temperature to a processing unit, providing a desired cabin temperature and an indexed optimal carbon dioxide level to the processing unit, calculating deviation of the measured cabin air carbon dioxide level from the indexed optimal carbon dioxide level, calculating optimal cabin air relative humidity level based on the desired cabin temperature, and, based on the calculation, determining the optimal rate at which to provide outside air to the cabin to achieve the calculated optimal cabin air relative humidity level and the indexed optimal carbon dioxide level, determining the recirculation rate required to provide outside air to the cabin at the determined optimal rate and providing instructions to an air-circulation and -recirculation control unit to provide air to the cabin of the vehicle at the optimal rate.