Abstract
The Japan Automobile Manufacturers Association (JAMA) announced its self-restraint to reduce volatile organic compounds (VOC) in the vehicle interior. Evaluation of self-restraint requires measurements in actual cars, which needs long time to obtain results. Therefore, demand exists for a measurement method that uses VOC emission factor from vehicle inner components prediction the VOC concentration in the vehicle interior. On the basis of measurements in the vehicle interior, this study focused on formaldehyde, acetaldehyde, toluene, ethyl benzene, xylene, and p-Dichlorobenzene (p-DCB) as the target VOC. Six VOC diffusion sources were then identified using the sampling-bag method. We placed the six identified inner components to be tested in bags in order to determine if the VOC concentrations were solely because of those inner components. Because aldehydes were also emitted from the vehicle paint, we excluded them from the target VOC. Thereafter, we determined the measurement conditions of the chamber (temperature, humidity, and ventilation) and measuring method of VOC emission from the backside of a specific inner component. The measurement conditions are based on the evaluation results of the chamber conditions, and JASO standard Z125 which is related to the temperature and ventilation inside a vehicle. The concentrations inside the vehicle were estimated by summing up the VOC emission factor of each of the identified inner components. The difference of measured and the predicted values, respectively, were 13% for toluene, 11% for ethyl benzene, 26% for p-DCB and Xylene predicted value were found to have a fit to measured value. The results of this work revealed that the VOC concentrations in the vehicle interior can be predicted on the basis of the amount of VOC emission factor from the identified inner components.
