Alternative Fuels for Army Vehicles

Principal Investigators
Dennis Assanis, Zoran Filipi (U. of Michigan)

University Researcher
Dohoy Jung (U. of Michigan)

Industry
Admir Kreso (Detroit Diesel Corp.)
William de Ojeda (International Truck & Engine)
Paul Chandler (Terra Fuel)
Alex Knafl (General Motors Corp.)
Ralph Cherrillo (Shell)
Bill Cannella (Chevron)

Government
Peter Schihl, Patsy Muzzel, Herb Dobbs (TARDEC)

Students
Mike Smith, Ashwin Salvi, Markus Schmitzberger (U. of Michigan)

Our goals are:

• Characterize the interplay between properties of alternative fuels and mixing, combustion and emissions of medium and heavy diesel engines
• Investigate the effects of JP-8, Gas-To-Liquid S-5 (from different suppliers), biodiesel and blends.
• Development of dual-use fuel injection, variable geometry turbocharger (VGT) and exhaust gas recirculation (EGR) control strategies for meeting the performance targets, maximizing the potential benefits and minimizing the penalties of operating the heavy-duty diesel with alternative fuels.

The results will provide critical knowledge to make it possible to operate diesel engines efficiently and safely with JP-8, or to substitute JP-8 with synthetic (CTL) or bio-fuels; to make reliability and durability recommendations when using alternative fuels, in addition to guiding performance-based fuel specifications.
Furthermore, this will promote energy conservation and energy independence of the country.

The complexity of the fuel-engine system dictates a primarily experimental approach in the early stage of the research. The medium duty and the heavy duty test cell setup will utilize sophisticated in-cylinder diagnostic techniques for determining the effects of using alternative fuels on the fuel injection, combustion, performance and emissions characteristics. While the emphasis is on experiments, the newly generated insight into the interplay between fuel properties and in-cylinder processes will support model development in a related project (Diesel Engine System and Fuels: Modeling Approach), thus enabling future synergistic efforts.

Strategies for eliminating the torque and fuel economy penalty associated with the operation of a diesel engine with JP-8 fuel, due to its lower density, viscosity and cetane number (CN), were demonstrated last year. A similar approach will be followed for operation with other fuels, starting with a synthetic (GTL) S5. The effects of engine fuel properties on the nature of heat release (premixed and diffusion patterns) will be carefully monitored to analyze the observed differences. The scope is expanded to include tests on an additional engine, namely a medium-duty International V8 6L engine. Preliminary findings indicate a significant impact on the mixture preparation and combustion system on observed trends, hence adding a higher speed engine, operating at higher speeds and with high swirl will significantly broaden the applicability of findings.