To provide an exhaust gas flow rate measuring device and an exhaust gas flow rate measuring method which can detect the flow rate of exhaust gas accurately without any optical influences.
An upstream side and downstream side sensors 4, 5 are arranged, at an interval B, in an exhaust pipe 3 connected to an automobile engine 2. An operation circuit 6 connected to the upstream side and downstream side sensors 4, 5 obtains a phase difference D (s) between upstream side and downstream side signals 50, 60 of the sensors 4, 5, obtains a gas flow rate V (m/s) by dividing the interval B by the phase difference D, and obtains a flow rate Q (m3/s) by multiplying the gas flow rate V with a sectional area A (m2) of the exhaust pipe 3. As compared with a Karman's vortex flow rate measuring device, this device is not subjected to optical influences caused by, for example, soot generated during burning, and can be improved in detection accuracy. As compared with a conventional thermocouple flow rate measuring device requiring a heat transfer part, this device may dispense with any heat transfer part. Accordingly, the simplification of the structure can be realized.
Toshio Nakamura
Miyazaki Yoshio
Kaoru Onozuka