A Control System for Maintaining Passenger Cabin Air Quality

This paper presents a control methodology to maintain vehicle cabin air quality within desirable levels, giving particular attention to gaseous contaminants carbon dioxide (CO₂) and carbon monoxide (CO). The CO₂ is generated by the occupant exhalation while the CO is assumed to be ingested with the incoming outside air. The system is able to detect and improve cabin air quality by controlling the recirculation flap of the ventilation system to control the amount of outside air intake. The methodology is demonstrated in the laboratory using controlled experiments with a production level automotive HVAC module. The results indicated that the designed control system can work automatically and control the CO and CO₂ gas concentrations within acceptable levels when operating in an environment of near zero ppm CO and 600 ppm CO₂ concentrations, respectively.