Ethanol is an alternative fuel that has remained unavailable to school buses, but one day that could change, especially after Cummins obtains more data tied to a demonstration project with the California Energy Commission that is showing twice the power and torque of similar 2.8-liter displacement engines.
Cummins announced the partnership Monday to develop an engine and powertrain that also reduced carbon dioxide emissions in medium-duty vehicles by as much as 80 percent, compared to baseline gasoline engines. Cummins is targeting CO2 amid the federal government's new Corporate Average Fuel Economy standard that also targets the reduction of greenhouse gases.
Cummins has actually operated its new ETHOS 2.8L engine more than 1,000 miles and 1,500 hours over the past two and a half years in an MT-45 Class 5 walk-in van, which a company representative said has a duty cycle that "would be somewhat similar to that of a school bus." But he added that the ETHOS this isn't available for any market at this point.
Still, the company said in a release that the engine powered by E-85, a blend of 85 percent cellulosic ethanol derived from corn and 15 percent gasoline, has exceeded the 50 percent CO2 emissions reduction outlined in the project's goals. The ETHOS also offers and 250 hp and 450 pounds of torque, which Cummins said is nearly twice the power of gasoline and diesel engines with a similar 2.8-liter displacement.
"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," stated Wayne Eckerle, Cummins vice president of research and technology. "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. We are very appreciative of the CEC's funding participation in this important effort."
The ETHOS engine also incorporates an integrated stop-start system, which Cummins said 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's foot is lifted from the brake, the system automatically starts the engine to seamlessly allow acceleration from the stop. Cummins said its integrated specific system controls, along with a robust starter, smart alternator and sensors, are all designed to handle the additional stop-start duty cycle and maintain reliable operation over the life of the engine.
Cummins also worked with Allison Transmission to integrate the 2000 Series transmission for a "smooth and efficient stop-start 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 provided NextGen engine oils specifically designed for lower CO2 emissions, and Freightliner Custom Chassis, which provided a prototype MT45.
The company said a final on-road validation testing phase is underway in the Sacramento, California, area since June and continuing into this month, and is being managed by Cummins Pacific, the exclusive California and Hawaii distributor for Cummins Inc.