Abstract

Dimethyl ether (DME) is an alternative fuel which, of late, has shown tremendous potential in reducing the pollution emissions of automobiles. Simultaneously, electronic actuated fuel injectors, with the use of solenoids, have repeatedly demonstrated superior performance with respect to needle movement control. This thesis, in order to combine the advantages of both electronic actuation and DME fuel, presents an adaptation of the novel use of solenoid operated fuel injectors with DME. The thesis also sets to reduce injector nozzle seat wear, by reducing the bouncing of the injector needle at the bottom of its stroke. The injector design presented incorporates a lengthened elastic rod, a new driving circuit for the solenoid, and incorporates them into a common rail system. The thesis also presents, for the first time in the literature, a methodology for measuring the force acting on the nozzle seat in injector closing. Through modeling, simulation and testing, an injector compatible with DME fuel was designed, where injector needle movement was properly controlled, and nozzle seat force reduced. As such, an important step has been taken in developing technology allowing DME to be a more common alternative fuel in automobiles.