Parallel Sequential Boosting for a Future High-Performance Diesel Engine 2022-01-5005
Future Diesel engines must meet extended requirements regarding air-fuel ratio, exhaust gas recirculation (EGR) capability, and tailored exhaust gas temperatures in the complete engine map to comply with the future pollutant emission standards. In this respect, parallel turbines combined with two separate exhaust manifolds have the potential to increase the exhaust gas temperature upstream of the exhaust aftertreatment system and reduce the catalyst light-off time. Furthermore, variable exhaust valve (EV) lifts enable new control strategies of the boosting system without additional actuators. Therefore, hardware robustness can be improved.
This article focuses on the parallel-sequential boosting concept (PSBC) for a high-performance four-cylinder Diesel engine with separated exhaust manifolds combined with EV deactivation. One EV per cylinder is connected to one of the separated exhaust manifolds and, thus, connected to one of the turbines. By closing one of the EVs, the corresponding exhaust manifold and the connected turbine are deactivated. The engine operates in mono-turbo mode at low power output. The second turbocharger (TC) blends in as the power requirement increases.
A novel design process for complex turbocharging systems is presented, which bases on a validated one-dimensional (1D) gas-exchange simulation model with an advanced TC modelling methodology. The design process handles the high degree of freedom in the layout process with clearly defined optimization steps based on identified system limitations. The modelling of the heat transfer within the TCs has been calibrated with measurement data from a hot gas test bench. This enables an accurate prediction of the exhaust gas temperature upstream of the exhaust aftertreatment system.
The designed parallel sequential boosting system demonstrates high potentials in full-load and part-load operation, increasing the exhaust gas temperature downstream of the turbine by up to 40°C at an engine speed of n = 1250 1/min and a brake mean effective pressure of BMEP = 2.7 bar compared to the baseline engine with a serial-sequential boosting concept (SSBC). Furthermore, a higher rate of high-pressure EGR can be generally achieved with that system.
Citation: Xia, F., Schlosshauer, A., Tidau, F., Sommerhoff, A. et al., "Parallel Sequential Boosting for a Future High-Performance Diesel Engine," SAE Technical Paper 2022-01-5005, 2022, https://doi.org/10.4271/2022-01-5005. Download Citation
Author(s):
Feihong Xia, Adrian Schlosshauer, Florian Tidau, Arnd Sommerhoff, Helmut Kindl, Hanno Friederichs, Stefan Pischinger, Jakob Andert
Affiliated:
RWTH Aachen University, Ford Werke GmbH, RIC Aachen
Pages: 11
Event:
Automotive Technical Papers
ISSN:
0148-7191
e-ISSN:
2688-3627
Related Topics:
Exhaust gas recirculation (EGR)
Diesel / compression ignition engines
Exhaust manifolds
Air / fuel ratio
Exhaust valves
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