<div class="htmlview paragraph">Increasing population and a rising necessity for mobility and transportation require a growing environment protection. In the USA and in Europe legislative concluded new emission limits to reduce cold start emissions for passenger cars.</div> <div class="htmlview paragraph">An effective method to reduce HC and CO during the cold start of combustion engines is secondary air injection. Secondary air injection mixes fresh air into the exhaust gas during cold start and achieves an oxidation of HC and CO. This exothermal oxidation elevates the exhaust gas temperature and decreases light-off time of the catalyst.</div> <div class="htmlview paragraph">A new compact secondary air injection system for integration in the intake manifold, the so called <i>Secondary Air Charger</i> was developed. In principle the secondary air charger works as a turbocharger, driven by the pressure drop at the throttle valve.</div> <div class="htmlview paragraph">This system was analyzed on test rigs, engine test bench and passenger car, successfully. Performance of the secondary air charger was comparable to the performance of commercial secondary air systems. Compactness and minimum weight of the new secondary air charger enables integration of the whole secondary air injection system in the intake manifold.</div>