Cummins says it’s developing an E85-fueled engine that reduces carbon dioxide emissions by as much as 80% compared with a baseline gasoline-powered medium-duty truck engine.
The work was jointly funded by Cummins in partnership with the California Energy Commission, with support from Allison Transmission, Valvoline division of Ashland Inc., and Freightliner Custom Chassis. CEC is providing $2,712,140 and project participants are providing a minimum of $3,790,027, the commission said.
Called Ethos 2.8L, the engine is a spark-ignition adaption of a 2.8-liter four-cylinder diesel previously shown by Cummins. Its fuel, E-85, is a clean-burning blend of 85% ethanol and 15% gasoline, said Wayne Eckerle, vice president for research and technology.
Carbon dioxide, or CO2, is the primary greenhouse gas emitted through human activities, accounting for the vast majority of greenhouse-gas emissions in the United States. It is thought to be contributing to climate change around the world.
More than 1,000 miles and 1,500 hours have been accumulated on the Ethos 2.8L engine over the past 2.5 years, demonstrating that this technology is capable of far exceeding the 50% CO2 emissions reductions outlined in the project's goals.
A final on-road validation testing phase has been underway in the Sacramento, Calif., area since June and continuing into this month. It is being managed by Cummins Pacific, the California and Hawaii distributor for Cummins.
"The Cummins Ethos engine, developed through a research partnership with CEC, clearly demonstrates that by combining innovative engine design and combustion approaches with low-carbon alternative fuels, we can determine a path to significant reductions in greenhouse gas emissions," said Eckerle.
"Cummins produces industry-leading emissions-controls technologies and products, and we continue to explore new ways to make our company stronger and our customers more successful, while reducing our environmental footprint," he said.
The Ethos engine operates at diesel-like cylinder pressures and incorporates advanced spark-ignition design, he said. Its output, up to 250 horsepower and 450 pound-feet, is similar to gasoline and diesel engines nearly twice its 2.8-liter displacement.
The Cummins Ethos 2.8L engine also incorporates an integrated stop-start system, which further reduces fuel consumption and emissions. In stop-start mode, the engine shuts down after the vehicle comes to a complete stop and the brake pedal remains depressed. As the driver lifts his foot from the brake, the system automatically starts the engine to allow acceleration from the stop.
Cummins-integrated specific system controls, along with a strong starter, smart alternator and sensors, are designed to handle the additional stop-start duty cycle and maintain reliable operation over the life of the engine, according to the company.
Cummins worked closely with Allison to integrate a 2000 Series automatic transmission for efficient urban-type operation. The transmission is equipped with hydraulic circulation features to ensure smooth operation and quick vehicle launch during stop-start driving.
Additional partners in the project included Valvoline, which supplied NextGen engine oils specifically designed for lower CO2 emissions, and Freightliner Custom Chassis, which provided a prototype MT45 Class 5 walk-in van.
Using corn-derived E-85, the high thermal efficiency and power-to-weight ratio of the engine results in 50 to 58% lower well-to-wheels CO2 emissions compared with the gasoline engine baseline.
Using second-generation lignocellulosic-derived E-85, the powertrain's efficiency features deliver 75 to 80% lower well-to-wheels CO2 emissions, depending on the drive cycle.
Cellulosic E-85 is less intensive in land use, tilling, fertilizing and harvesting than corn-derived E-85. Although not in high-volume production today, cellulosic ethanol represents a promising production pathway for future fuels, Cummins and CEC said.
More information about the Cummins Ethos 2.8L engine and California's Ultra-Low Carbon Powertrain Program is at http://www.energy.ca.gov/drive/projects/ARV-10-044.html.