Serge Klein

Influence of sensor and communication setup on electric cam phaser control quality

This study investigates the control quality of an electric cam phaser system. The impact of different sensor concepts, synchronization algorithms, controller and hardware topologies on the control quality is examined by using a transient simulation covering the electric cam phaser, valve train, mechanical transmission and a wide variety of cam- and crankshaft trigger wheels. Limited angular accuracy effects are simulated by realistic sensor models and the processing of sensor signals by a real-time capable synchronization algorithm. Nonlinear friction in transmission and valve train are considered by the simulation accordingly. Furthermore, the effects of distributed controller algorithms based on conventional electronic control units are evaluated. Communication latencies have a strong impact on the control plant and are taken into account during controller definition. The effects of different layouts are compared in the time domain, and a sensitivity analysis is carried out to evaluate the effects of different parameters on the cam phasing control quality. The control quality is measured in terms of overshoot, phasing duration and energy consumption of a phasing event. Using a sensor fusion for the current cam phasing angle and an integrated controller layout – that is, an architecture without any communication delay – improves the controllability and reduces overshooting, phasing duration and electrical energy consumption under transient conditions.

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.

Durchgängig von der Straße auf den Prüfstand bis zur Simulation – eine qualitative Analyse am Beispiel RDE

Die kontinuierliche Verscharfung gesetzlicher Randbedingungen bezuglich des Emissionsverhaltens von Kraftfahrzeugen und die Berucksichtigung marktspezifisch unterschiedlicher Kundenanforderungen fuhren sowohl zu einer stetig anwachsenden Komplexitat des Antriebsstrangs, des Gesamtfahrzeugs als auch komponentenubergreifender Funktionalitaten des Antriebsstrangs. Erganzt um die zunehmende Anzahl der Fahrzeugderivate auf den globalen Absatzmarkten stellen diese Herausforderungen seit Jahrzehnten die bekannten Treiber fur steigende Aufwande bei der Konzeptionierung und Validierung im Rahmen der Fahrzeugentwicklung dar.