/ 131 Flow direction v sin α α v sin α T2, R1 v c c D T Transmitter R Receiver c speed of sound v flow media velocity α inclination angle T1, R2 Differential pressure drop Orifice measurement pipe Blow-by flow Differential pressure transducer DIFFERENTIAL PRESSURE For the determination of ��low-��y �� ow the orifi ce measurement principle ��differential pressure measurement procedure) is used. A neck ��orifi ce�� in the tu��e cross-section provokes a pressure drop that is measured by means of a differential pressure sensor. The shape of the orifi ce of the AVL Blow By Meter means that it, on the one hand, ensures the accuracy in ��oth �� ow directions and, on the other, prevents condensation at the orifi ce that might modify the cross-section. The selected shape of the orifi ce allows for a broad dynamic range of 1:50. 6 GRAVIMETRIC (OIL CONSUMPTION METER) This measurement is based on the gravimetric principle. This means that oil is always sucked to a defi ned level or completely into a measurement tank with modifi ed dip stick or an oil drain plug. Afterwards, the weight is determined with the help of a precision pressure sensor. After the weight has been determined, the oil is pumped back into the oil pan of the engine. This measurement cycle consists of three steps: pumping (out), weighing and pumping (back). The difference between two subsequent measurement cycles results in the oil consumption. ULTRASONIC TRANSIT DIFFERENTIAL TIME The measuring principle is based on the ultrasonic transit-time differential method. Two ultrasonic pulses are sent simultaneously through the �� owing medium from Transmitter 1 (T1) and Transmitter 2 (T2). One pulse is propagating into the �� ow and the other one against it. The interaction between the speed of sound c and the velocity of �� ow v accelerates the pulse on one of the paths and decelerates the pulse on the other path. This effective propagation velocity results in different transit times through the medium: The signal at Receiver 1 (R1) arrives faster than the signal arriving at Receiver 2 (R2). The device measures the speed of sound traveling either way, corresponding to t1 and t2. 1 2 3 4 5 7 8 1 Oil dip stick 2 Measuring tank 3 Refilling tank 4 Pump 5 Drain plug 6 Electronics 7 PUMA CDH – Task 8 Hybrid interface or serial interface via RS232
Solutionskatalog_2017_E
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