|
A major difficulty in dealing with automotive exhaust emissions is
the so-called "cold-start" problem. During the first
several minutes of driving, before the catalytic converter reaches
its operating temperature, a substantial amount of hydrocarbon
emissions occur. Social concerns about the environment and new
regulations for low-emissions vehicles make it essential to reduce
these hydrocarbon emissions. We are investigating one potentially
attractive solution to the cold-start problem, namely the use of a
"hydrocarbon trap." The concept is to store the hydrocarbons
by adsorption in a porous material upstream of the catalytic converter
during cold start. As the exhaust stream heats up, the stored
hydrocarbons would be released and could flow downstream to the
catalytic converter, which is by then hot. The difficulty lies in
finding a suitable adsorbent material. We are using both molecular
modeling and experiment to find and optimize appropriate nanoporous
molecular sieve materials for this important application.
This work was performed by Ken Czaplewski.
|
