Raymond Freymann

A future energy supply based on Liquid Organic Hydrogen Carriers (LOHC)

This contribution describes a concept for the establishment of a competitive energy distribution network based on Liquid Organic Hydrogen Carrier (LOHC) compounds. These compounds are characterized by the fact that they can be loaded and un-loaded with considerable amounts of hydrogen in a cyclic process. This concept links the technical challenge of storing temporary and local energy over-production from regenerative sources with the vision of a sustainable, hydrogen-based mobility. The proposed LOHC compounds have many physico-chemical similarities to diesel. Thus, LOHCs could make use of the existing energy infrastructure (e.g. tank ships, storage tanks or fueling stations) and enable a slow and step-wise replacement of the existing hydrocarbon fuels by alternative LOHC fuels. We consider LOHCs as an attractive way to provide wind and solar energy for mobility applications in the form of liquid energy carrying molecules of similar energy storage densities and manageability as todays fossil fuels.

The turbosteamer: A system introducing the principle of cogeneration in automotive applications

BMW’s turbosteamer is the first system to use the potential of waste heat in order to enhance the efficiency of the combustion process in the automobile. Applying the principle of cogeneration, fuel consumption can be reduced in a four-cylinder spark ignition engine by more than 10 per cent or, conversely, power and performance may be increased accordingly under relevant stationary operating conditions.

Application of stroboscopic and pulsed-laser electronic speckle pattern interferometry (ESPI) to modal analysis problems

Accurate structural models are key to the optimization of the vibro-acoustic behaviour of panel-like structures. However, at the frequencies of relevance to the acoustic problem, the structural modes are very complex, requiring high-spatial-resolution measurements. The present paper discusses a vibration testing system based on pulsed-laser holographic electronic speckle pattern interferometry (ESPI) measurements. It is a characteristic of the method that time-triggered (and not time-averaged) vibration images are obtained. Its integration into a practicable modal testing and analysis procedure is reviewed. The accumulation of results at multiple excitation frequencies allows one to build up frequency response functions. A novel parameter extraction approach using spline-based data reduction and maximum-likelihood parameter estimation was developed. Specific extensions have been added in view of the industrial application of the approach. These include the integration of geometry and response information, the integration of multiple views into one single model, the integration with finite-element model data and the prior identification of the critical panels and critical modes. A global procedure was hence established. The approach has been applied to several industrial case studies, including car panels, the firewall of a monovolume car, a full vehicle, panels of a light truck and a household product. The research was conducted in the context of the EUREKA project HOLOMODAL and the Brite-Euram project SALOME.

Dynamic response of coupled structural-acoustic systems

A new approach, based on Lagranges energy equations, is described for the derivation of the generalized equations of motion of coupled structural-acoustic systems. Furthermore attention is given to consideration of the acoustic properties of sound absorbing materials and damping pads in the generalized formulation of the coupled equations of motion.

Der Turbosteamer: Ein System zur Kraft- Wärme-Kopplung im Automobil

Mit dem Turbosteamer stellt BMW erstmals das Potenzial der Abwarmenutzung zur Wirkungsgradverbesserung von Verbrennungskraftmaschinen im Automobilbereich dar. Durch Kraft-Warme-Kopplung werden bei einem Vierzylinder-Ottomotor Verbrauchseinsparungen von mehr als 10 % oder entsprechende Leistungssteigerungen in relevanten stationaren Betriebspunkten erreicht.

Holographic modal analysis for the separation of narrow-spaced eigenmodes

The automotive industry has particular interest in obtaining modal models of panel-like structures in the higher frequency range where the accuracy of FE-models normally is not longer sufficient to predict the dynamic response of a car body structure to a given operational excitation. Experimental modal analysis can fill this gap. However, the sensors which are currently used for the acquisition of vibrational data (accelerometers, laser vibrometer) are limited in spatial resolution and therefore higher-order panel modes are hard to be investigated. Holographic interferometry is widely used for qualitative and quantitative measurements of the mode shapes of dynamic systems, where its high spatial resolution outperforms any other kind of vibrational dynamic sensor. The limitations of holography with respect to the sampling rate can be overcome in the context of modal analysis by using stepped sine testing. A large number of holograms is then automatically recorded and evaluated. First results on a test structure which exhibits narrow-spaced eigenmodes are shown using this kind of measurement setup with a high frequency resolution. The dense vibration data enables the modal analysis software to separate the eigenmodes.

Integration of pulsed-laser ESPI with spatial domain modal analysis: results from the SALOME project

The present paper discusses the various critical elements of a modal testing system based on pulsed-laser holographic ESPI measurements. Such system allows making very high spatial resolution measurements on panel-like structures at frequencies which are of relevance for the vibro-acoustic behavior.

Integrierte Längs- und Querf;uhrung

Schwerpunkt eines Querfuhrungsassistenten ist die Integration unterschiedlicher Fahrerassistenzfunktionen zu einem Gesamtsystem. Die vorgestellten Systeme schliesen an das ConnectedDrive-Konzept der BMW Group an, das den Fahrer durch Assistenzsysteme unterstutzt. Der Fahrer bleibt jedoch weiterhin fur die Fahrzeugfuhrung verantwortlich. Die bei der Integration von Teilsystemen zu losenden Aufgaben, zum Beispiel die Situationsinterpretation, werden am Beispiel der Spurwechselassistenz aufgezeigt.

Integration of pulsed-laser ESPI with spatial domain modal analysis

The present paper discusses the various critical elements of a modal testing system based on pulsed-laser holographic ESPI measurements. Such system allows making very high spatial resolution measurements on panel-like structures at frequencies that are of relevance for the vibro-acoustic behavior. Next to the optical parts, the integration with the modal analysis procedure, including the integration of geometry and response information, is reviewed. The ESPI based Image-domain frequency response functions are accumulated frequency by frequency. Special attention is paid to the modal parameter extraction of the large DOF number data, for which a special data reduction scheme was developed. The approach has been applied to several case studies related to car panels. The research was conducted in the context of the Brite/Euram project SALOME and the EUREKA project HOLOMODAL.

Infrasound and low frequency noise in the passenger compartment of vehicles

The acoustic response determined in the passenger compartment of a vehicle is characterized by resonances in the infrasound and low frequency range. A simple mathematical model is derived allowing the numerical identification of the related low frequency acoustic eigenmodes. The numerically obtained results are verified on the basis of experimental investigations.