IMES DEVELOPS NEW TYPE OF COMBUSTION SENSOR

IMES noted that the use of closed loop combustion control (CLCC) in the latest generation of gas engines permits very high engine efficiency. The stability and robustness of cylinder pressure sensors have become increasingly important while reliable control and monitoring require accurate information about the current state of the combustion process in each cylinder.

IMES has been developing a new High-Robust Sensor (HRS), which it describes as a completely new development in sensor technology. It is a robust and very accurate type of sensor that features a front membrane and an M14 thread. The patented sensor transmits the pressure via a special designed measuring spring, which captures deformations on the measuring surface via a resistor bridge. The surface generates a voltage signal proportional to the pressure change.

The measuring spring can withstand abnormal combustion with extremely high pressure rise up to 1000 bar/ms and deliver a high degree of thermodynamic accuracy for engine control purposes. It is designed for more than one billion load cycles. The resistance structure of the measuring spring and the ceramic pads are connected by wire bonding, as a result the electrical connection withstands temperatures of more than 350°C.

The sensor has been subjected to robust tests. Thermodynamic tests on IMES’ single cylinder test engine confirmed its accuracy relative to a water-cooled piezoelectric reference sensor. Measurements of 18 bar IMEP @ 1500 rpm have a PMI deviation of 0.5 bar in comparison to the reference.

The sensors have also been installed on the asphalt carrier BIT Viking since March 2017 as a test project. IMES stated that after 7,000 continuous operating hours, the sensor was a span error of < 0.5% compared with the sensor’s original calibration.