Application of Concentric Cam Shafts to a Passenger Car Diesel Engine to Significantly Improve the NO
Trying to improve the modern diesel engine's
NOx/soot tradeoff without giving up fuel economy
continues to be a core target for the engine development community.
One of the options not yet fully investigated for the diesel is
applying variable valve events to the engine breathing process.
Already used in some heavy-duty applications, late intake valve
closing has long been regarded as a possible strategy for small
diesel engines. Single-cylinder tests applying fully variable valve
events have demonstrated potential but also raised doubts about VVA
benefits on automotive size diesel engines. Full engine testing
using realistic valve train technology is seen as key to judging
its true performance because it covers not only combustion benefits
but also influences like engine pumping on emissions and CO₂.
Different to past publications, this paper focuses on testing a
production feasible variable valve train technology on a fully
instrumented modern Common Rail diesel engine. Applying a
concentric intake cam in the described way to increase valve event
duration allows running an over expanding combustion cycle (Miller
Cycle). The benefits on the NOx/soot tradeoff as well as
other effects are described.
Citation: Joergl, V., Becker, M., Wyatt, S., Stapelmann, A. et al., "Application of Concentric Cam Shafts to a Passenger Car Diesel Engine to Significantly Improve the NOx /Soot Tradeoff," SAE Int. J. Engines 4(2):2434-2450, 2011, https://doi.org/10.4271/2011-24-0134. Download Citation
Volker Joergl, Michael Becker, Steve Wyatt, Andreas Stapelmann, Juergen Meusel