Abstract
This paper presents the results of investigations of the performance of the catalytic converter system for a heavyduty diesel engine. The catalytic converter system removes nitrogen oxide (NOx) from the exhaust gas by selective catalytic reduction (SCR) using urea solution as the reductant. The step responses of the catalytic converter system and of two different control strategies for the injection of urea solution to steps in engine power were measured on a dynamic test bench. Using a mean-value model of the catalytic converter system the behaviour is explained qualitatively. A test cycle and a quality criterion are then proposed to evaluate the effects of various control strategies. Measurements taken on the test bench confirm the feasibility of this procedure.