Search Results

This paper describes a recently developed sensor, the High-Performance Flowmeter (HPF), which measures flow rates in raw, undiluted exhaust. The HPF is based on the principle of acceleration or deceleration of an ultrasonic pulse due to a flow of gas. It allows a two-directional detection of flow with high accuracy and high sampling rates. Formerly, all flow sensors were limited to low temperatures and low sampling rates when measuring the flow rates directly in raw exhaust. An entirely new principle has been developed for this generation of ultrasonic pulses which improves the performance of ultrasonic flow sensors dramatically. Using this principle, such flow sensors can be used for the first time to measure dynamic flow rates in raw exhaust at high temperatures with sampling rates up to several hundred hertz.