Patent ID: 8047082

Claim:
A device for determining a mass flow of a first gas flowing in a flow channel in an intake pipe of an internal combustion engine of a motor vehicle, the device comprising: sound transducers arranged at respective ends of a measuring path configured to send and receive sound signals in the flow channel in the intake pipe; a temperature sensor for determining a temperature of an overall mass flowing in the flow channel; an evaluation unit arranged in a signal path downstream of the sound transducers, wherein the evaluation unit is configured to: determine a flow rate of the overall mass flowing in the flow channel and a speed of sound based on delay times of the sound signals received by the sound transducers, determine the overall mass flow based on the flow rate, the temperature, and a pressure of the overall mass in the flowing channel, ascertain a proportion of a second gas flowing in the flow channel at a temperature above 10° C. and based on the speed of sound and the temperature, and correct the overall mass flow to obtain the mass flow of the first gas; and a pressure sensor configured to determine the pressure of the overall mass in the flowing channel.