Drive with lowest friction losses

The AVL FRISC™ Floating Liner Engine

A single cylinder engine for unique piston-liner friction analysis in fired conditions

When piston velocity meets friction force, the result is friction power loss. Such losses become especially high when cylinder pressure increases and enhances the lateral piston forces which act upon the liner. To reduce this friction and the associated energy losses, engineers search for the best piston/piston ring/liner combinations and the lubrication and thermal control of surface contact components.

The AVL floating liner FRISC engine, when combined with dedicated piston liner friction measurement and test processes, provides the ideal conditions for high-precision friction measurement. Built around a ‘liner carrier’, it features a FRISC-specific liner-head seal ring gasket. Combustion pressure, force and temperature can all be analyzed by the system, which is optimized to enable the exchange of hardware components and avoid interference with measurement and calibration activities.

Thanks to our testbed automation system we can offer precisely calibrated test processes for stationary and transient test routines. Precise test repetitions allow the accurate comparison of the friction results from different model variants. Temperature, speed and engine load are automatically controlled by the system to minimize the variability of boundary conditions.

AVL FRISC is designed to measure even the smallest variations in friction: Piston to liner friction losses are in the range of 0,3 bar FMEP. Changing a piston ring variant may change these FMEP figures by 1%: 3 millibar only! The system is tailored to measure such small variations.

With access to each sensor signal the user is able to gain complete insight to the signal evaluation process. Boundary conditions such a temperature, pressure traces, speed and load can all be recorded for each combustion cycle. This complements the root cause analysis of each variant’s friction characteristics.

Further benefits include:

  • Easy piston or liner hardware variant exchange
  • Access to all force components acting on the liner via AVL X-ion
  • Reliable seal between liner and cylinder head