Engine Combustion Analysis – Engine Pressure Measurement for Research and Development - KISTLER - #39

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www.kistler.com 39 Measuring ø16 ø26 M14x1,25 Type 1111A SW 23 Type 1233A1 Type 1203Csp Type 1233A2 48,6 38 256,7 330,5 16 13 Example of low-pressure measuring point in good position near exhaust valve. The sensor is mounted in a switching adapter Exhaust Pressure Measurement Using a Switching Adapter Typical measuring cycle To cope with the high gas temperatures the sensors have to be actively cooled in the exhaust. The cooled switching adapter Type 7533A… provides the optional conditioning of exhaust gases which in turn yields the best sensor accuracy and longest life. Use of the cooled switching adapter also permits simple zeroing of the sensor signal with the engine running. For exhaust pressure measurements the sensor Type 4045A… or 4075A… in the cooling adapter Type 7533A… is recommended. Principle of operation: The pressure sensor is only exposed to the hot exhaust gas during measurement (e.g. 100 cycles). A pneumatic valve controls exposure of the sensor to exhaust gas pressure or ambient pressure. This allows convenient zeroing of the sensor signal with the engine running immediately prior to the measurement and under identical thermal conditions. The intermittent exposure of the sensor to hot exhaust gas makes it possible to maximize the measurement accuracy over a long service life. Racing: Racing applications demand particularly small mounting dimensions and low mass. The miniature high-temperature sensor Type 4007B… with adapter Type 7525A… has proven well suited for this application. Control pressure off Control pressure on Control pressure off Measurement period Control pressure 0 bar 2 …6 bar Cylindre pressure Exhaust pressure of sensor in cooled switching adapter Ambient/Exhaust pressure Ambient pressure Äp = offset correction value Switching Adapter Type 7533A... Piezoresistive Sensors