Impact Of Time Aligned Measurement Parameters On Brake Specific Emissions

As per global emissions legislation requirements running test cycles and reporting brake specific emissions is the key requirement. Engine gaseous emissions measurement is mandatory requirement for ON Highway and OFF Highway applications for transient duty cycles during testing at test cells. To meet the stringent emission limits is one of the challenging tasks considering the nature of transient duty cycles with accurate measurement of lower emission values. Similarly calculating accurate results is critical since there are several factors which impacts the accuracy of calculated results. As per regulatory test methods, there is guidance on measuring the time lag through an experiment method and accounting the same during the results calculation, however during dynamic conditions, the time lags will vary and influence the calculated results. This paper focuses on understanding critical parameters which leads to variations in dynamic condition of time lag of measured emissions parameters. It also discusses through experimental observations, impact of static and dynamic time lag of measured emissions parameter on results calculations & sensitivity analysis. The paper finally summarizes the list of variables which can impact the brake specific emission results calculation.