Investigating NOx vs CO2 Tradeoff in Heavy Duty Emissions Through the Years Under the Scope of CARB’s 3-Bin Moving Average Window Method

With the rise in urban pollution level over the last few years, regulatory agencies around the world have taken multiple steps to ensure engine exhaust pollutant are well monitored and properly regulated. Yet there exists a significant difference in emissions rates in various operating conditions between US and European products which currently uses a Moving average window (MAW) approach for their in-use compliance testing and certification program. Using WVU’s vehicle data collected using PEMS devices, this study aims at investigating the NOx versus CO2 tradeoff found in heavy duty diesel engines equipped with different aftertreatment technologies, under the scope of the recently proposed CARB 3Bin-MAW heavy duty in-use testing method set to be implemented for model year engines 2024+. Using the CARB document, the new program was implemented on vehicles from both goods movement and delivery vocation with the aim of highlighting any benefits this method includes. This approach towards engine certification allows for a more comprehensive final result that accounts for low load and idle operations, as opposed to the current Not-to-Exceed (NTE) method encompasses a narrow band of operation, mainly highway. This allows manufacturers and regulators to observe and analyze heavy duty vehicle emissions under the most challenging operations