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Talks and Poster Presentations (with Proceedings-Entry):

B. Geringer, P. Hofmann, J. Graf, T. Hofherr, P. Weyand, F. Lorenz, S. Schilling:
"Adaptive Continuous Spark Ignition as Enabler for High Dilution EGR Operation";
Talk: 2nd International Conference on Ignition Systems for Gasoline Engines, Berlin, D (invited); 2014-11-24 - 2014-11-25; in: "Ignition Systems for Gasoline Engines", M. Günther, R. Tröger (ed.); DCM Druck Center Meckenheim GmbH, (2014), 199 - 228.



English abstract:
Striving for lowest fuel consumption, the highly diluted gasoline combustion process is a key technology to reach 95 g/km CO2. Similar effi ciency and CO2 reduction can be achieved by lean burn combustion. The significantly improved effi ciency however is countered by the need for a more complex ignition system. High EGR dilution or lean burn combustion is lacking a well-sustained development of the fl ame kernel due to its thermodynamic boundary conditions and in-cylinder fl ow and turbulence.
These combustion methods require a high and consistent energy delivery
to the spark over a certain duration. High-energy, single spark coils
can only do half of the job since both stored coil energy and burn time is limited. Various advanced ignition systems have been developed in the past to address these challenges, such as Multi-Charge ignition (MCI)for stratified combustion. Still, MCI has to interrupt the spark to recharge the coil - an unavoidable necessity that can lead to a cooling-down of the flame kernel during the coil recharge time.
Based on the MCI concept, Delphi has developed an ignition system with
two coils, called Coupled Multi-Charge ignition (CMC). It combines repeated firing with an uninterrupted spark for any commanded time. Unlike other dual coil concepts, like Dual Coil Ignition (DCI) or Dual Coil Offset ignition (DCO), the intelligent algorithms used in CMC guarantee either the maximum energy output when needed or a limited energy delivery if the combustion cycle does not require the built-in high power capability.
This scalable energy delivery is controlled by both the Engine Control Unit (ECU) and course of each individual combustion event; a unique Feature of the CMC.
This paper proposes a different way to specify ignition systems, explains the working principle of a CMC system, and then compares a high-energy single spark system and the CMC system on different engines; including a single cylinder gasoline engine with high EGR dilution, and a lean burn CNG engine ("CULT"). The tests on the CNG engine were performed at the IFA of the Vienna University of Technology (Prof. Dr. Bernhard Geringer).
For the CMC system, the dyno runs clearly show a shift of the dilution or lean burn limit before the engine combustion becomes too unstable (i.e., before drivability issues rise).

Created from the Publication Database of the Vienna University of Technology.