Abstract
Evolution of automotive diesel engines has led to the production of smaller and smaller engines with increasingly higher torque. The reduction in external dimensions means smaller flywheels, and the increase of torque rates, higher cyclic irregularities that today's flywheels even with a dual mass techniques are no longer able to cope with.
Because of this, "damper" type absorber devices which control torque vibrations due to cyclic irregularities are no longer efficient to decrease rotating vibrations to an acceptable level.
The best solution to cope with these problems is a tuned rotating pendulum : P.A.R.I.S, (Pendulum Acyclism Reducer Integrated System). This vibration absorber system can be easily integrated into a standard engine flywheel. P.A.R.I.S. systems show a very high efficiency level. Normally, in order to decrease the 2 nd harmonic level (mainly responsible for cyclic irregularities in 4 strokes 4 cylinders engines) to 60 %, a standard flywheel would have to have around 15 times its actual mass.
The mean torque level is not affected by P.A.R.I.S., only the instantaneous torque is counterbalanced by the pendulum. In addition, the P.A.R.I.S. system device has the great advantage of being independent of engine speed. It is efficacious throughout the whole range of speed, as compared to damper vibration absorbers, which are tuned for a specific frequency.
On the other hand, P.A.R.I.S is not adapted for the whole harmonic range generated by the engine, but only for those harmonics it has been tuned for.
Another positive aspect of this solution is that it is a full mechanical system, needing no electronic controls, which consumes hardly any energy and these due only to small friction losses. Application examples targeted by this patented system are : torque regulation, due to reduction of cyclic irregularities in order to achieve smaller vibration levels, idle speed decrease for consumption and pollutant reductions, in camshaft applications - increase of the maximum rotating speed.