Johannes Scharf

Road-to-rig-to-desktop: Virtual development using real-time engine modelling and powertrain co-simulation

By front-loading of the conventional vehicle testing to engine test bench or even further forward to offline simulations, it is possible to assess a large variation of powertrain design parameters and testing manoeuvres in the early development stages. This entails a substantial cost reduction compared to physical vehicle testing and hence an optimisation of the modern powertrain development process. This approach is often referred to as road-to-rig-to-desktop. To demonstrate the potential of this road-to-rig-to-desktop methodology as a seamless development process, a crank angle–resolved real-time engine model for a turbocharged gasoline engine was built with the simulation tool GT-POWER®. The model was validated with measurement data from an engine test bench and integrated into a vehicle co-simulation, which also includes a dual clutch transmission, the chassis, the environment and the automated driver. The most relevant functions of the engine and the transmission control systems were implemented in a Simulink-based software control unit. To verify the engine model in the transient vehicle simulation, two 900-s time windows from a 2-h real driving emission test, representing urban and motorway conditions, are simulated using the developed co-simulation platform. The simulation results are compared with the respective vehicle measurement data. The fuel consumption deviation caused by the combustion engine model is within 5%. The transient system behaviour and the dominant engine operation points could be predicted with a satisfying accuracy.

An extended calculation approach of exhaust thermocouple temperatures in one-dimensional gas exchange simulation for turbocharged gasoline direct-injection engines

A new model approach is presented to determine exhaust thermocouple temperatures in gas exchange calculations for turbocharged gasoline direct-injection engines. Since the measured thermocouple temperature at turbine inlet is typically used as a criterion to fix the required fuel enrichment for turbocharger protection, an accurate prediction of this value is decisive in the development of future engine concepts. Therefore, a detailed one-dimensional thermocouple model has been developed which captures the measurement principle by a physical approach. The major advantage of this approach is the integration of detailed data of convective heat transfer along the thermocouple protrusion length from three-dimensional computational fluid dynamic exhaust flow simulations. Detailed investigations by means of three-dimensional and one-dimensional simulations are presented for steady-state flow as well as in full and part load operations of four turbocharged gasoline direct-injection engines. For further verification, the test carriers have been equipped with special temperature measurement technology like various thermocouple penetration lengths and profile thermocouples. A comparison with measured temperatures shows that at turbine inlet, a prediction deviation of less than 10 K can be achieved with the detailed one-dimensional model.

Elektrische Zusatzaufladung - neue Freiheitsgrade durch höhere Bordnetzspannungen

Die elektrisch angetriebene Aufladung ist bereits seit vielen Jahren immer wieder Gegenstand von Untersuchungen im Fahrzeugsektor. Sowohl Fahrzeughersteller als auch Zulieferer haben verschiedene Konzepte vorgestellt. Dem Konzept des elektrisch angetriebenen Verdichters in Kombination mit einem Abgasturbolader (TC) werden hierbei die grosten Erfolgschancen eingeraumt.

All lambda 1 gasoline powertrains

The introduction of new emission legislations in Europe (EU6d-TEMP) and China (CN6b) increases the pressure on the automotive industry to develop new and better exhaust gas aftertreatment and combustion systems. The fulfilment of PN and NOx targets in real world driving scenarios and increasingly electrified powertrains have led to the introduction of gasoline particulate filters (GPFs) and enlarged catalytic converters. Now, on top of these major upgrades, the monitoring of CO emissions according to Real Driving Emissions (RDE) legislation puts a potential ban on high load enrichment for thermal component protection into focus. Hence, new technologies which enable Lambda 1 operation in the entire map of a gasoline engine are urgently required. This paper presents technology packages for component protection at high load stoichiometric operation as well as operational strategies for ultra-low CO emissions in all real driving scenarios. Assessed solutions span from base engine modifications to water injection and vehicle cooling concepts as well as to control functions. Favorable combinations are identified taking into consideration costs and realistic integration in ongoing vehicle programs.

Extreme lean gasoline technology – best efficiency and lowest emission powertrains

Development of mobile propulsion technology is driven by fuel consumption and exhaust emission reduction. New gasoline powertrains currently developed at FEV address both these major trends using extreme lean combustion systems to combine best efficiency with lowest emission levels. This paper elaborates on the technology potentials and development methodologies used to handle challenges associated with gasoline lean burn.

Extreme downsizing for gasoline engines – fun to drive with extremely low emissions

This paper elaborates different boosting systems for extreme downsizing levels considering the target of optimal transient performance:

Integrating the turbo charging system optimization into the engine development

Increasing demands on the load build up, fuel consumption and emission of vehicle drive trains are leading to a stronger integration of supplier component parts into the optimization process of the whole engine. In this context the exhaust gas turbocharger plays an important role in future drive train concepts especially for the reduction of CO2 emissions. This is caused on the one hand by the technical complexity of this device and on the other hand by the significant influence of the turbocharger on driving performance and fuel consumption. The latter applies especially for the trend in engine developments towards smaller engines. “Off shelf solutions” as they were common until just a few ago to achieve performance variants of an engine family are only exceptions in contemporary applications. This article from FEV and the Institute for Combustion Engines (VKA) of the RWTH Aachen University describes an integral approach for the development and optimization of turbochargers by integration of different tools and methods into the development process of the drive train.

Integration von Aufladesystem- und Motorentwicklung

Gestiegene Anspruche an Fahrzeugantriebe bezuglich Leistungsentfaltung, geringen Kraftstoffverbrauchs und niedrigsten Emissionen fuhren zunehmend zur Integration von Zuliefererkomponenten in den Optimierungsprozess des Gesamtmotors. In diesem Kontext nimmt der Abgasturbolader gerade bei zukunftigen Antriebskonzepten zur Verminderung der CO2-Emissionen eine besondere Stellung ein. Ursache ist zum einen die technische Komplexitat dieser Energiewandlungsmaschine und zum anderen der signifikante Einfluss des Turboladers auf Fahrverhalten und Kraftstoffverbrauch. Letzteres gilt insbesondere vor dem Hintergrund des Motorentwicklungstrends hin zu kleinen Motoren. Dieser Artikel der FEV und des Lehrstuhls fur Verbrennungskraftmaschinen (VKA) der RWTH Aachen University beschreibt einen ganzheitlichen Ansatz zur Entwicklung und Optimierung von Turboladern durch die Integration unterschiedlicher Werkzeuge und Methoden in den Antriebsentwicklungsprozess.