Browse Publications Technical Papers 2004-01-0641

Plastic Turbo for Secondary Air Injection 2004-01-0641

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.
A useful method to reduce HC and CO during the cold start of combustion engines is secondary air injection. Secondary air injection feeds fresh air into the exhaust system during cold start and achieves an oxidation of unburned HC and CO. This exothermal oxidation elevates the exhaust gas temperature and decreases light-off time of the catalyst.
A large portion of the emissions in the FTP 75 cycle is produced during the first seconds of the cold start. This requires a fast rising secondary air mass flow during the cold start of the engine. Electrically driven secondary air pumps achieve this requirement with a high cut-in current.
Mann+Hummel developed the so called secondary air charger with a very short response time. In principle the secondary air charger works as a turbocharger, driven by the pressure drop at the throttle valve. First aluminum prototypes have been tested very successfully. Further improvement was achieved with a secondary air charger with plastic wheels.
The first part of this paper describes the performance of the secondary air charger in a passenger car compared with an electrical secondary air pump. The second part of the paper compares secondary air chargers with plastic and aluminum wheels. Reduction of rotating mass and decreased friction in the bearings affects short response time and increased secondary air flow with plastic wheels.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 16% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:

Mapping of Airflow Patterns in Engines with Induction Swirl


View Details


Study of the Flow Field Development During the Intake Stroke in an IC Engine Using 2–D PIV and 3–D PTV


View Details


Assessment of the 3D Flow in a Centrifugal compressor using Steady-State and Unsteady Flow Solvers


View Details