August 15, 2017
UC Riverside Study Finds Near-Zero Buses Beat Lowest Emissions Standards
Near-zero-NOx heavy-duty natural gas engines ran significantly cleaner than their certification standards across all duty cycles in a new study released by the University of California, Riverside, College of Engineering—Center for Environmental Research and Technology. The researchers focused on Los Angeles County Metropolitan Transportation Authority buses equipped with the Cummins Westport ISL G engine.
“We have tested two of the ISL G near-zero 8.9-liter engines, one in a refuse hauler and one in a Metro bus. In both cases, the NOx emissions were surprisingly low [at] 99 percent cleaner than the current standard and 99.96 percent cleaner than the 2004 standard,” said Kent Johnson, associate research engineer for CE-CERT and lead researcher on this study, in the press release.
The study found that the engine performed below CARB’s optional low-NOx limit of 0.02 grams per brake horsepower-hour. In some normal driving conditions, it tested as low as 0.0007 g/bhp-hr.
“The near-zero engine will provide immediate NOx relief to our region at a low cost, and, coupled with renewable natural gas, would provide long-term stability to our energy and climate change needs,” Johnson said. “Pursuing RNG technology is a promising and visionary pathway for California and is recommended by UCR’s RNG research center.”
EDCO Orders 25 New Near-Zero-NOx Refuse Collection Trucks
EDCO, a waste and recycling company in Southern California, has purchased 25 new near-zero-NOx natural gas–powered collection vehicles to add to its fleet, which already includes 200 NGVs. The company has begun fueling all of its natural gas trucks with RNG to further reduce its emissions in the region.
Photo ©Westport Innovations, used by permission