Exhaust Emission Control on the New 500 SL and 500 SL Structure and Mode of Operation

This paper describes the exhaust emission control system designed for the new Mercedes-Benz sports car generation 300 SL and 500 SL, Remarkable features of the catalytic converters are maximum environmental compatibility, i. e. minimum of emission and noise under all driving conditions. By reduced back-pressure, they also contribute greatly to the well known requirements of a sports car: high performance and high torque over the entire engine-speed-range. Apart from an effective exhaust gas aftertreatment, great efforts were made to prevent the formation of pollutants under all driving conditions. This work is done by intelligent motor management consisting of digital spark control, mechanical-electronic injection, variable valve timing and EGR. Especially in the start-up and warm-up phase the exactly matching of all these systems, supported by secondary air injection, made it possible to reach the goal of spending minimum time - with less possible raw exhaust - in reaching light off temperature of the catalyst.