Allows dimethyl ether use in a 4-cylinder diesel engine
Challenge Saturated Propane Saturated DME PrototypePrototype Research has shown that CIDI 14 Bar, 60° C (compression ignition, direct Liquid DME Throttle FuelFuel injection) engines fueled with 10 bar, 25° C dimethyl ether (DME) can Injection Liquid DME Injection achieve ULEV exhaust emis- 20 Bar, 30° C Return Cam SystemSystem sions levels while maintaining the thermal efficiency of a conventional diesel. However, the unique physical 2:1 Intensifier properties of DME present challenges to its utilization. DME is a gas at atmospheric Fuel delivery system. pressure but liquifies under modest pressuriza- tion. DME also has very low viscosity, leading cylinder. If piston speed is low enough, inlet to high internal leakage in supply pumps, flow is equal to the piston displacement. If solenoid valves, and fuel injectors. Such piston speed is high, inlet flow is lower than limitations require that significant modifications the piston displacement; the fuel vaporizes be made to conventional fuel injection and then re-liquifies upon compression by equipment to accommodate the use of DME the piston. When all of the fuel is liquefied, in a diesel engine. pressure rises and fuel flows out.
Technology Accomplishments Description The pump has been integrated into a complete common rail fuel system and packaged for A high efficiency, variable displacement axial use on a Ford DIATA engine. Additional fuel piston fuel pump has been designed for use system components have been designed. These in DME fueled CIDI engines. The wobble include: fuel injector assembly, rail pressure Contacts plate actuated pump design permits variable and back pressure control valve mountings, displacement through inlet throttling and high fuel filter, supply and return lines, and fuel Lucito Cataquiz efficiency (low leakage) through positive tank assembly. Manager, Alternative Fuels sealing. 202-586-0729 A uniquely designed Benefits 202-586-9811 fax fuel tank delivers liquid [email protected] DME under pressure of ■ CIDI engines have the highest thermal efficiency of Wendy Clark 10 bar to the pump. A any demonstrated automo- National Renewable cam actuated intensifier tive power plant. Energy Laboratory increases fuel pressure supplied to the throttle 303-275-4468 ■ DME fueled engines could inlet to 20 bar. As the 303-275-4415 fax limit harmful emissions piston strokes down, [email protected] without sacrifice to engine fuel flows through the efficiency. throttle and into the
Variable displacement fuel pump.
April 2001 http://www.ott.doe.gov/success.html Future Activities
Emissions and performance demonstrations are underway using the developed fuel system installed on a Ford DIATA CIDI engine fueled with DME.
Partners in Success
■ AVL Powertrain Technologies, Inc.
■ National Renewable Energy Laboratory
http://www.ott.doe.gov/success.html