DME is an ultra-clean burning diesel fuel replacement that does not produce any particulate (PM) emissions (black smoke). It can be manufactured at low cost from a variety of resources, including stranded natural gas, coal and biomass. Converting bus diesel engines to use bio-DME made from non-food crops, industrial CO₂ and other biomass could significantly reduce greenhouse gas emissions, in addition to the elimination of PM.

Production-intent 4th-generation DME fuel system for passenger cars. Shown is the high-pressure pump, common rail and injectors. Click to enlarge.

In the mid-late 1990s, AFT designed a DME fuel system for the DOE’s PNGV program (the 80 mpg car). The company is currently working on a fourth-generation system intended for production in 2011. This production intent design has one-third fewer parts than previous designs and can operate at 50% higher pressures. It has been designed to be manufactured on flexible and low-cost CNC equipment.

TIGGER provides up to $100M in discretionary funds appropriated by The American Recovery & Reinvestment Act of 2009 (ARRA) for grants directed to public transit agencies for capital investments that will assist in reducing energy consumption, greenhouse gas emissions, or both, of public transportation systems.

Eligible projects may include, but are not limited to: replacement of existing vehicles with more energy-efficient vehicles, repowering existing vehicles with more energy-efficient propulsion, incorporation of wayside energy storage for captured regenerated energy in rail transit systems, and extensions to catenary fixed guideway systems that result in reduced energy consumption.

Each submitted TIGGER proposal must request a minimum of $2 million but not more than $25 million; FTA envisions providing a 100% Federal share to each project. Applications were due 22 May 2009.