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High combustion pressure in combination with high pressure gradient, as they e.g. can be evoked by high efficient combustion systems and e.g. by alternative fuels, acts as broadband excitation force which stimulates natural vibrations of piston, connecting rod and crankshaft during engine operation. Starting from the combustion chamber the assembly of piston, connecting rod and crankshaft and the main bearings represent the system of internal vibration transfer. To generate exact input and validation values for simulation models of structural dynamic and elasto-hydrodynamic coupled multi-body systems, experimental investigations are done. These are carried out on a 1.5-l inline four cylinder Euro 6 Diesel engine. The modal behaviour of the system was examined in detail in simulation and test as a basis for the investigations. In an anechoic test bench airborne and structure-borne noises and combustion pressure are measured to identify the engine´s vibrational behaviour.

The application of a turbocharger, having an electric motor/generator on the rotor was studied focusing on the electric energy recuperation on a downsized gasoline internal combustion engine (turbocharged, direct injection) using 1D-calculation approaches. Using state-of-the art optimization techniques, the settings of the valve timing was optimized to cater for a targeted pre-turbine pressure and certain level of residual gases in the combustion chamber to avoid abnormal combustion events. Subsequently, a steady-state map of the potential of electric energy recuperation was performed while considering in parallel different efficiency maps of the potential generator and a certain waste-gate actuation strategy. Moreover, the results were taken as input to a WLTP cycle simulation in order to identify any synergies with regard to fuel economy.

Downsizing of Gasoline Direct Injection engines is a way to reduce greenhouse emissions. A downsized engine will have a much higher specific power density, caused by a significant higher brake mean effective pressure (BMEP). This higher BMEP can be enabled by a turbocharger in combination with gasoline direct injection. In addition, good efficiency is accompanied by fast combustion, i.e. a fast heat release rate. All these factors can lead to an increased level of combustion noise excitation, which means in turn a higher level of radiated noise. Thus a study on impact factors on the combustion noise excitation was carried out on a small I4-gasoline engine, having spray-guided direct injection, combined with a turbocharger. It was found that high intake tumble levels, which e.g. are caused by the intake port geometry or different actuation strategies of the swirl control device, can lead to an increased level of noise and roughness.

A trend in vehicle propulsion of converting from power sources such as a naturally aspirated internal combustion engine to turbocharged engines (Downsizing), multi-mode combustion systems (stratified charged combustion, HCCI) or multi-power source propulsion systems such as hybrid power-trains, can be observed. The subsequent switching between these different combustion modes or power sources, and, more importantly, the incorporation of turbochargers (turbo-lag) can affect the driveability, i.e. the smoothness of torque provision during transient driving manoeuvres. So far there is a lack of methodologies that can quantify and objectively describe vehicle transient acceleration events from a driver's point of perception. Thus an approach was developed while incorporating the acceleration transducers of men, the vestibular apparatus, into a longitudinal vehicle model with a transient engine / powertrain model.

The ability to switch off the internal combustion engine (ICE) during vehicle operation is a key functionality in hybrid powertrains to achieve low fuel economy. However, this can affect driveability, namely acceleration response when an ICE re-engagement due to a driver initiated torque demand is required. The ICE re-start as well as the speed and load synchronisation with the driveline and corresponding vehicle speed can lead to high response times. To avoid this issue, the operational range where the ICE can be switched off is often compromised, in turn sacrificing fuel economy. Based on a 48V off-axis P2 hybrid powertrain comprising a lay-shaft transmission we present an up-front simulation methodology that considers the relevant parameters of the ICE like air-path, turbocharger, friction, as well as the relevant mechanical and electrical parameters on the hybrid drive side, including a simplified multi-body approach to reflect the relevant vehicle and powertrain dynamics.

There is no doubt that the modern internal combustion engine (ICE) is approaching its theoretical limits in terms of efficiency. Owed to the fact that the conversion of fuel-bound chemical energy into effectively usable power by combustion is largely defined by the fuel properties, the combustion process and the implicit phenomenon of abnormal combustion is a governing factor that limits further efficiency increases. However, the use of a knock-resistant fuel such as methane is leading to a significant raise in the average combustion pressure and total engine efficiency. In turn this requires a base engine architecture that is specially designed to cater the increased thermal and mechanical requirements so that the positive fuel properties can be fully exploited. Furthermore, an improvement of the energy balance is achieved by utilizing the kinetic energy stored in the vehicle by means of electrical recovery.