Reduction of Rotational non uniformity in Automotive Powertrains Against the background of reducing carbon dioxide emissions and the fact that the automotive industry is bound by law to realize that, new drive train concepts have to be developed. Fully electrified drive trains offer the potential to reduce emissions to a minimum. But very high expenses for research and development paid by industry and a weak existing infrastructure, offering broad access to electricity, make other drive train concepts more attractive. Especially reciprocating engines with a reduced number of cylinders and smaller engine displacements are interesting, since the underlying technology is familiar and therefore less expense for research and development are expected.
In the future automotive industry will still have to offer engines with high power to remain competitive. Both the trend to less cylinders and charged engines as well as reduced engine speeds are changing the excitation characteristics of reciprocating engines dramatically. The results are lower engine orders and higher amplitudes of engine torques.
Considering an automotive powertrain as a mechanical vibration system, lower eigenfrequencies can now become more critical and vibration amplitudes are basically higher. The results are negative influences on the overall vibration behavior and a higher level of structure-born sound. Conventional systems like two mass flywheels or centrifugal pendulums are not capable anymore to compensate such strong excitation levels. Within this research project the focus is on developing innovative concepts offering new possibilities to reduce vibrations in future powertrains. From understanding the phenomenology of vibrations through optimizing system performance in presence of dissipation mechanisms modeling and simulation under defined boundary conditions has to be done iteratively.
