The Vmas Emission Gas Flow Meter is developed to detect diluent vehicle exhaust flow based on vortex street principle and emission gas concentration by zirconia sensor. It is one of the core Vmas system components for measuring diluent gas flow and oxygen concentration, pressure, temp. of emission gas from petro engines. This model is complied to the national standard GB 18285-2018 "Limits and Measurement Methods for Pollutant Emissions from Gasoline Vehicles (Dual Idle Method and Simple Working Condition Method)". This model is mainly applied to vehicle inspection stations and automobile manufacturers, etc.