Small engine emissions testing laboratory development and emissions sampling system verification.

摘要

With the recent scrutiny of engine emissions and a focus towards higher fuel efficiencies, there has been an increase in demand for small, efficient engines and small engine emissions testing. Small engines have proven to provide high efficiency performance for systems including refrigeration units, generators, compressors and numerous other off-road applications. In the past, the existing emissions testing facilities at West Virginia University's (WVU) Center for Alternative Fuels, Engines and Emissions (CAFEE) have been focused towards the testing of heavy duty diesel engines.In order to expand the emissions testing capabilities at CAFEE, a new small engine emissions testing laboratory was needed. Over a two year period a new small engine emissions laboratory (SEEL) was designed and built at CAFEE's Westover facility. The new SEEL used a 40 hp alternating current (AC) dynamometer with an in-line slip ring torque sensor. It included full dynamometer and engine cooling capabilities. Custom built software provided the control algorithms to allow for engine mapping, steady state, and transient emissions tests. Safety systems including shaft guards and an automatic kill switch provided a safe working environment and would isolate damage in case of a mechanical failure.The SEEL was designed to be used with existing raw and dilute emissions sampling systems. The raw emissions sampling system was recently developed at WVU and needed to be verified against a trusted dilute emissions sampling system in order to prepare it for testing with the SEEL. A set of tests were performed which included simultaneous sampling of one engine by both sampling systems. The results from these tests showed that raw sampling system CO, CO2, and NOx passed their verification criteria of 2%, 2%, and 5% difference respectfully. The HC measurement systems did not pass the 10% verification criteria. The verification of HC was a complex issue that was beyond the scope of this study.