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Fuel induction techniques have been found to be playing a very sensitive role in the operation of a gas-fueled engine. This paper describes the experimental evaluation of an electronic injector for operating a spark ignition (SI) engine using clean-burning alternative fuels such as compressed natural gas and hydrogen. Test data have also been generated with a blend of the two fuels (hydrogen and CNG) in various proportions to determine the flow characteristics of the blend for engine operation. Results show that the electronic injectors for gaseous fuel operation can be conveniently adapted to existing engines. A precise and accurate control of flow was achieved at pressure levels of 3.44 bar and 9.31 bar (absolute pressure).

Although studies have shown benefits in both emissions and fuel renewability for hydrogen fuelled vehicles, implementation of such a vehicle has been slow due, in part, to a limited hydrogen infrastructure. This situation, along with the proven benefits associated with natural gas and natural gas/hydrogen fuelled vehicles resulted in the need to develop a vehicle capable of operating on any blend of natural gas/hydrogen, at anytime. Such a vehicle dubbed; Variable Gaseous Fuel (VGF) vehicle, in principle, could use a thermal conductivity sensing device developed at the University of California, Riverside, College of Engineering - Center for Environmental Research and Technology (CE-CERT) to directly measure the composition of a natural gas/hydrogen blend. The resulting electrical signal from this device can, in turn, be used as an input to “multiple map” engine control module to control fuel injection and ignition timing.

This paper describes an evaluation of a series of commercially available natural gas fuel injectors, originally designed for heavy-duty diesel application, for use with hydrogen fuel in an electronic fuel-injected internal combustion engine. Results show that sonic flow, pulse-width-modulated electronic gaseous fuel injectors provide accurate and stable metering of hydrogen gas at fuel pressures between 25 and 200 psig. A linear flow rate of hydrogen was observed with a low standard deviation error during pulse width modulation. Plots of flow rate of hydrogen (mg/injection) versus pulse width (PW) are presented for inlet pressures from 25 to 200 psig for selected injectors. In addition, injector response tests were conducted and found to have time delays (time it takes the injector to open) between 2.6 ms and 2.3 ms at 25 psig inlet pressure. Time-delay times increased linearly between 4.0 ms and 3.0 ms at 200 psig.

A University of California, Riverside (UCR) 1992 Ford Ranger truck was converted to operate on hydrogen which is produced from water electrolysis at the UCR College of Engineering-Center for Environmental Research and Technology (CE-CERT) Solar Hydrogen Research Facility (SHRF). The Ford Ranger's 2.3L engine was modified to operate as a lean-burn, hydrogen fuel internal combustion (IC) engine, using a Constant Volume Injection (CVI) system with closed-loop control and exhaust oxygen feedback. The vehicle had excellent starting, idle, and shut-down operation; a range in excess of 161km (100 miles); and initially operated with virtually no preignition problems typical of hydrogen fuel engines. At speeds above 64 km/ h (40 mph), the vehicle exhibited performance characteristics similar to comparable gasoline-powered vehicles, although further improvements are needed at lower speeds.