Shuttle Bus Demonstration Project

Development of a Dimethyl Ether (DME)-Fueled Shuttle Bus Demonstration Project

  Students:   Shirish Bhide, Elana Chapman, Jennifer (Stefanik) Eirich Faculty/Supervisors: Prof. Joseph Perez, Department of Chemical Engineering David Klinikowski, Pennsylvania Transportation Institute Dr. James Hansel, Air Products and Chemicals, Inc. Prof. Andr‚ Boehman, Director of the Combustion Laboratory

Sponsors: Pennsylvania Department of Environmental Protection, Program Manager – Susan Summers. Federal Energy Technology Center, US Department of Energy, Program Manager – John Winslow Air Products and Chemicals, Inc., Program Manager – Edward Heydorn Navistar International, Technical Consultants – X. Gui and Pranab Das Champion Motor Coach, Technical Consultant – Gerald Buck

Objective: To determine a methodology for operating a production turbo diesel engine on dimethyl ether and demonstrate the performance, emissions and durability of the conversion approach in a Faculty/Staff shuttle bus on the University Park campus of the Pennsylvania State University.

Approach: To protect the fuel pump and injectors from excessive wear, due to the lack of lubricity for DME, diesel and DME will be blended at levels that will provide sufficient lubricity to protect the fuel injection system. An external pressurized fuel delivery system will maintain 90-150 psi in the fuel lines to keep DME in the liquid phase and in solution with the diesel fuel. After the laboratory engine conversion, we will examine a range of DME/diesel blend ratios and will seek to operate the engine on as high a DME concentration as is possible, while still protecting the engine from excessive wear. Then, this conversion approach was implemented on a Champion Motor Coach “Defender” model shuttle bus, equipped with the Navistar T444E.

Shuttle Bus Demonstration

Results: The Navistar T444E turbo diesel engine has been successfully operated on blends of dimethyl ether and diesel fuel. Examination of the viscosity and miscibility of DME-diesel blends was also completed. The conversion strategy used in the laboratory was applied to the campus shuttle bus starting in Fall 2001 and resulting in a successful demonstration of the DME Fueled Shuttle Bus in April 2002. The bus was deployed on the Faculty/Staff Shuttle Bus loop on June 5, 2002. However, reliable operation of the bus was not achieved until July 2002, due to hardware difficulties. The Pennsylvania Transportation Institute assisted with performance and emissions tests on the shuttle bus prior to and after its conversion and operation on DME-diesel fuel blends on the University Park campus. The DME Shuttle Bus operated from early June, 2002 until September 30, 2002 with the converted fueling system. It ran on blends of DME in diesel fuel ranging from 5 wt.% up to 25 wt.%. Optimal performance was observed at around 10-12 wt.%, when considering driveability, smoothness of operation and other factors. After September 30, 2002, the shuttle bus was converted back to operation on its original fueling system and the bus continues to operate on the Campus loop.

Publications: Eirich, J., E. Chapman, H. Glunt, D. Klinikowski, A. L. Boehman, J. G. Hansel and E. C.Heydorn. Development of a Dimethyl Ether (DME)-Fueled Shuttle Bus. Society of Automotive Engineers Technical Paper No. 2003-01-0756. Chapman, E.M., A.L. Boehman, P.J.A. Tijm and F.J. Waller. Emission Characteristics of a Navistar 7.3L Turbo diesel Fueled with Blends of Dimethyl Ether and Diesel Fuel. Society of Automotive Engineers Technical Paper No. 2001-01-3683. Bhide, S., E. Chapman, J. Stefanik, H. Glunt, L.I. Boehman, A.L. Boehman, F.J. Waller, “Development of a Dimethyl Ether-Fueled Shuttle Bus,” in ACS Fuel Chemistry Division Preprints, 47(2), 562-563 (2002). Bhide, S.V., Boehman, A.L. and Perez, J.M., “Viscosity of DME-Diesel Fuel Blends,” in ACS Fuel Chemistry Division Preprints, 46(2), 400-401 (2001). Chapman, E. M., S.V. Bhide, A.L. Boehman, P.J.A. Tijm and F.J. Waller. Emission Characteristics of a Navistar 7.3L Turbo diesel Fueled with Blends of Oxygenates and Diesel. Society of Automotive Engineers Technical Paper No. 2000-01-2887 (2000).