2020 Volume 55 Issue 1 Pages 91-99
Closed loop combustion control (CLCC) has established itself in a new generation of large engines such that the capability of using of different fuels, with very high engine efficiency, is now possible. The cylinder pressure sensors required for this application are subjected to high loads from pressure, temperature, and mechanical shock. A simulation led by sensor development approach is indispensable for achieving the best possible trade-off between measurement accuracy and service life. Patented designs such as diaphragm and ceramic feedthrough, paired with PiezoStar® Crystal technology, presented in this paper, form a reliable sensor unit that can satisfy and exceed the market requirements. Additionally, new approaches for transmission of electrical charge have been developed. This has enabled a significant increase in the robustness of signal transmission.
The trend towards higher mean effective pressures (MEP) on large engines means that the sensors must have a higher resilience to these pressure levels. In the testing and validation of service life, a specifically designed endurance test system has been developed for a validation of a service life greater than 109 cycles. The endurance test system enables testing of sensors at an early stage.
Collaboration with engine manufacturers is essential for determining the environmental conditions, which define the requirements and boundary conditions for simulations and testing. Mounting location of the pressure sensor can affect the sensor service life due to environmental factors e.g. temperature and vibration. Collaboration with engine manufacturers allows for creation of robust installations and optimisation of interfaces. Field tests on appropriate target engines are still necessary as the final acceptance test, since the complete engine environment cannot always be fully replicated during the development stages.