Implementation of Aftertreatment System to Enable Tailpipe Emissions title Measurements of a Variable Valve Actuation Enabled Camless Diesel Engine

The experimental testbed used for engine testing at the Cummins Power Laboratory, located at Purdue’s Ray W. Herrick Laboratories, utilized a set of several emissions analyzers and sensors in order to measure engine out emissions of a Cummins 2010 Inline Six B-Series (ISB) diesel engine equipped with a variable valve actuation (VVA) system. To be able to simulate and/or measure the emissions at the tailpipe of the system, an aftertreatment model needed to be created and a physical aftertreatment system designed and implemented in the test cell. Tailpipe emissions are essential for determining the usefulness of VVA-enabled strategies for meeting increasingly stringent emissions regulations set on engine manufacturers by the United States Environmental Protection Agency (EPA) and other worldwide environmental regulators. An aftertreatment model was acquired from Cummins for use in the experimental testbed. The aftertreatment model is able to take engine out emissions and temperature data to predict the thermal response and chemical conversion efficiencies of a simulated aftertreatment system. This model was tested and validated using engine out emissions and thermal data over the Heavy Duty Federal Test Procedure (HDFTP), a transient drive cycle used by the EPA to test diesel engines’ ability to meet applicable emissions regulations. A physical aftertreatment system was designed and implemented in order to obtain actual measurements of aftertreatment system thermal response and tailpipe out emissions. This aftertreatment system was designed to meet a set of criteria decided upon by the Purdue research team and research sponsors. The aftertreatment system is capable of running in two modes: passive and active operation. Passive operation does not include active urea injection into the SCR. Active operation does include active urea injection into the SCR, enabling tailpipe NOx to be measured. Both passive and active modes of operation were performed and validated over the HD-FTP drive cycle using two baseline fuel injection profiles used by Cummins in ISB engine applications. While the aftertreatment system has been validated using two baseline fuel injection profiles, future work will include using more complex VVA-enabled strategies such as cylinder deactivation and internal exhaust gas recirculation in combination with the physical aftertreatment system in order to validate the benefits of these strategies on tailpipe emissions. The scope of VVA-enabled diesel engine research in the Cummins Power Laboratory has expanded from engine out emissions to tailpipe emissions and aftertreatment thermal response, thus being able to more accurately predict the ability for VVA-enabled strategies to help engine manufacturers meet tighter emissions regulations