Experimental Verification of Frequency Parameter in Plate-Type Viscous Flow Meters in Air Consumption Measurements of Internal Combustion Engines

Precise air consumption measurement is of vital importance in the development of internal combustion engines. Considerable errors are introduced in measurements of airflow rates when conventional flow meters are used under pulsating flow conditions.

Plate-type viscous flow air meters have been used satisfactorily under certain speed ranges. But it was found that the linear relationship between the flow rate and the pressure drop across the viscous flow air meter deviated at high engine speeds under the pulsating flow conditions found in internal combustion engines.

Viscous flow meters have been designed using two main equations-pressure drop and Reynolds number equations. Deviation from linear relationship at higher speeds has led to an attempt at experimental verification of the frequency parameter theoretically analyzed previously. Experimental results have shown that there is an exponential relationship between the frequency parameter and the distance between two adjacent plates of a viscous flow air meter which has to be considered in design calculations.