Investigation of the Gas Exchange (Scavenging) on a Single-Scroll Turbocharged Four Cylinder GDI Engine Universitat Stuttgart

Format:

Conference/Event

Author/Creator:

Wolany, Wolany, author.

Contributor:

Bargende, Michael

Berner, Hans-Juergen

Glahn, Claus

Conference Name:

SAE 2016 World Congress and Exhibition (2016-04-12 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2016

Summary:

For scavenging the combustion chamber during the gas exchange, a temporary positive pressure gradient between the intake and the exhaust is required. On a single-scroll turbocharged four cylinder engine, the positive pressure gradient is not realized by the spatial separation of the exhaust manifold (twin-scroll), but by the use of suitable short exhaust valve opening times. In order to avoid any influence of the following firing cylinder onto the ongoing scavenging process, the valve opening time has to be shorter than 180 °CA. Such a short valve opening time has both, a strong influence on the gas exchange at the low-end torque and at the maximum engine power. This paper analyzes a phenomenon, which occurs due to short exhaust valve opening durations and late valve timings: A repeated compression of the burned cylinder charge after the bottom dead center, referred to as "recompression" in this paper. By means of a new energetic analysis (available technical work capacity) the energetic contribution of the recompression to the boost pressure generation has been examined and is presented in this paper. Furthermore two different variable exhaust valve train systems in combination with a part-scroll-separation exhaust manifold are compared in this paper. The aim is to reduce fuel consumption at the nominal power. The two exhaust valve train systems increase the valve opening duration by either a two step system or by a system with the ability to offset the valve timing. It is shown in simulation results how both systems in combination with a prolonged part-scroll-separation in the exhaust manifold reach a potential to reduce fuel consumption up to 10 %.

Notes:

Vendor supplied data

Publisher Number:

2016-01-1024

Access Restriction:

Restricted for use by site license