A Study on Design Factors for the Air Ventilating System of Highway Express Buses

In efforts to prevent airflow noise and conserve heated and/or cooled air, express bus design has favored fixed windows, double glasses and closed structures with lower rates of ventilation. However, because there are many passengers in an express bus at the same time, offensive odor, carbon dioxide and other contaminants may accumulate in the bus's indoor. If sufficient amounts of ambient air are not brought into or distributed throughout the passenger compartment of the bus, in-bus air problems may result. An air ventilating system of the express bus that is properly designed, and that has a good performance of natural ventilation, can promote the air quality of the passenger compartment and the comfort of passengers. In order to design an effective ventilating system of the express buses, some design factors such as air inlet/outlet positions, air distribution, proportion of ambient air, and airflow control are considered computationally and experimentally in this work.