Emissions Performance of Two Catalyzed Trap Oxidizers on a Bus Engine

Regulated and some unregulated emissions from a Detroit Diesel Allison Division 8V-71TAC California bus engine were characterized over transient engine operation with and without catalyzed wire mesh particulate traps fitted in place of the standard exhaust manifold assemblies. Moderate reductions in particulate emissions were obtained, but initial trap design adversely affected performance of the 2-stroke, turbocharged, blower-scavenged bus engine. Most of the baseline engine performance was recovered with a second trap design. After catalyst aging, the second set of traps reduced baseline particulate emissions on both standard and low sulfur fuels by 60 and 70 percent, respectively.