DEMONSTRATION OF SCALED FLOWRATE TESTBED FOR EMISSION AFTERTREATMENT DEVICE TESTING UNDER REPRESENTATIVE ENGINE EXHAUST CONDITIONS

The continued development of aftertreatment devices has been critical in reducing engine tailpipe emissions and meeting ever-evolving regulatory standards. Initial phases of catalytic aftertreatment device evaluation often occur at physically scaled-down conditions, typically using laboratory benchtop reactors to test synthesized catalysts that are coated on mini-cores with flow rates of less than 10 SLPM evaluated and often in the range of 0.1-1 SLPM. These flows are often generated artificially using bottled gases and heaters, which do not reflect the conditions that occur under real engine operation. This reduced-scale approach is driven by cost and time constraints, as full-scale device testing requires more catalyst material and production time. Real multicylinder engines produce exhaust flows several orders of magnitude greater than what occurs on the benchtop, with numbers ranging from 1000 to >10,000 SLPM in typical on-road automotive applications. An intermediary scale approach that can bridge this flowrate chasm is necessary for the efficient rapid prototyping of novel catalytic reactions for aftertreatment applications. This manuscript focuses on validating a variably scaled testbed for catalyst testing that aims to eliminate barriers between cost-effective small-scale testing and realistic full-scale implementations. This study builds on a previous work incorporating a slip-stream approach driven by a venturi-ejector to route flow through a secondary branch containing the catalyst. The current investigation specifically focuses on improving the system’s overall flexibility in terms of accommodating new aftertreatment devices and operating conditions, as well as reducing required auxiliary instrumentation. Differences between the previous iteration of the system are detailed and discussed, as well as recommendations for further improvements to the system. Engine operating parameters such as intake pressure, equivalence ratio, spark timing, compression ratio, and ejector motive pressure are utilized to create the required catalyst inlet temperature, flows, and species concentration for evaluation. The system is tested using a blank catalyst for verifying composition across sampling locations, as well as to generate an operational emissions space for determining the system’s ability to be utilized for intermediate-scale catalyst testing. Initial results show the system’s repeatability and lack of species conversion with an inert monolith to be sufficient for eventually deploying a production catalyst and determining conversion efficiency.