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A team of student engineers at the University of Texas at Austin has designed and built “Texas Native Sun”, a solar powered vehicle for competition in GM Sunrayce U.S.A. The single-seat vehicle uses conventional photovoltaic solar cells to produce electricity for vehicle propulsion. The vehicle features graphite/epoxy composite monocoque construction, a high power-density permanent magnet electric motor, a mechanical/hydraulic continuously variable transmission, nickel-hydrogen satellite batteries, and a composite leaf spring suspension. The race strategies and tactics of energy management are optimized through use of a computer code which simulates the vehicle under race conditions. Much of the technology employed in the vehicle may one day become an ordinary part of future transportation systems which seek greater energy efficiency and less damage to the environment.

The technology thrust to develop an effective electromagnetic actuator for application in an active suspension system has precipitated a fresh look at the active control schemes in an effort to reduce the required force levels of the actuator. The resulting “near constant force” control algorithm is described and its ability to greatly reduce vehicle sprung mass motion is documented through simulation and single wheel station laboratory test stand results. The vehicle power and energy requirements associated with this unwanted vehicle vertical are analyzed and comparisons between the corresponding passive and active systems are presented. The success of the active system leads naturally to the conclusion that a passive suspension equipped vehicle will become power limited at a much lower speed than will this active system when traversing severe cross-country terrain.

The Rotating Linear Engine (RLE) derives improved fuel efficiency and decreased maintenance costs via a unique lubrication design, which decreases piston assembly friction and the associated wear for heavy-duty natural gas and diesel engines. The piston ring friction exhibited on current engines accounts for 1% of total US energy consumption. The RLE is expected to reduce this friction by 50-70%, an expectation supported by hot motoring and tear-down tests on the UT single cylinder RLE prototype. Current engines have stationary liners where the oil film thins near the ends of the stroke, resulting in metal-to-metal contact. This metal-to-metal contact is the major source of both engine friction and wear, especially at high load. The RLE maintains an oil film between the piston rings and liner throughout the piston stroke due to liner rotation. This assumption has also been confirmed by recent testing of the single cylinder RLE prototype.

Spark discharge properties were studied and characterized for varying gas compositions and spark plug geometries using a spark calorimeter and constant volume optical vessel. Two different 18 mm natural gas engine spark plugs were used in the experiments. All measurements were recorded under quiescent conditions and with a spark gap of 0.30 mm. The spark plug calorimeter was used for measuring thermal energy deposition to the gas for gas compositions of nitrogen, a stoichiometric mixture of nitrogen and methane, a stoichiometric mixture of nitrogen and methane diluted with 30% carbon dioxide by volume, and for air. Other measurements of interest included breakdown voltage, electrical energy delivered to the spark gap, electrical-to-thermal energy conversion efficiency, and spark duration, for pressures up to 28 bar at 300 K. The optical vessel was used for the combusting mixture of stoichiometric air and methane at pressures up to 28 bar.

The effects of fuel properties on the emissions of a production vehicle with a gasoline direct injection engine operating over the Federal Test Procedure (FTP) cycle were investigated. The vehicle used was a 1998 Toyota Corona passenger car with a direct injection spark ignition (DISI) engine. Engine-out and tailpipe FTP emissions for six fuels and a California Phase 2 RFG reference fuel are presented. Four of the test fuels were blended from refinery components to meet specified distillation profiles. The remaining test fuels were iso-octane and toluene, an iso-alkane and an aromatic with essentially the same boiling point (at atmospheric pressure) that is near the T50 point for the blended fuels. Statistically significant effects, at the 95% confidence level, of the fuels on tailpipe emissions were found. Correlations were sought between the properties of the five blends and the Emissions Indices for engine-out hydrocarbons and NOx and for tailpipe particulates.