Behavior of Tail Pipe Emission Diffusion behind a Van Type Truck

Abstract

In order to clear diffusion characteristic of tail pipe emission such as PM, its behavior behind a truck body was investigated using a model of 1/32 scale medium duty van type truck and a wind tunnel with moving floor. As for a modeled tail pipe exhausting emissions such as PM, THC and CO₂, CO₂ was used because CO₂ was main composition of exhaust gas, and turbulent diffusion behaviors of PM and gaseous emissions in the exhaust were considered as same. CO₂ was exhausted from the tail pipe to a downstream air flow around the truck and its spatial distribution behind the truck was measured. As the results, exhausted CO₂ was rolled up by the recirculation air flow behind the truck model when CO₂ exhausting gas velocity was less than the main flow velocity around the truck. However, almost of exhausted CO₂ did not roll up when CO₂ exhausting gas velocity was higher than the main flow velocity.