Effect of Cabin Volume on Build-up of Cabin Carbon Dioxide Concentrations from Occupant Breathing in Automobiles

Recently the author (Mathur, 2017) had presented a model to predict cabin carbon dioxide concentrations as a function of time, number of occupants, vehicle speed, body leakage characteristics, occupant lung capacities and concentrations of the carbon dioxide coming out from occupant’s mouth, blower position and vehicle age. The developed model was validated by the author for mid-sized vehicles (vehicles from D-segment). The simulated data was within ±11.5% of the experimental data.

In this paper the author has used the developed model to predict cabin CO₂ concentrations for vehicles from B, C & D segments. Or in other words, the effect of the cabin volume will be investigated on the rate of build-up of cabin CO₂ concentrations. Experimental tests were conducted on these vehicles and are compared to the simulated data. Detailed results have been presented in the paper. It has been found that the vehicles with the smallest interior volume has the largest and steepest rise of the cabin CO₂ concentrations in compared to larger volume vehicles.