Search Results

Aerogels are nanoporous structures with physical characteristics that make them promising for use in automotive exhaust catalysis systems: highly porous with low densities (<0.1 g/mL) and high surface area per unit mass (>300 m2/g) - features that provide favorable characteristics for catalysis of gaseous pollutants. Ceramic aerogels are also highly thermally insulating (∼0.015 W/mK) and able to withstand high temperatures. Aerogels can be made of a wide variety of ceramics (e.g. alumina, silica, titania) with other catalytically active metals (e.g. copper, cobalt, nickel) incorporated into their structures. This paper provides a brief overview of the rapid supercritical extraction (RSCE) method employed in this work for aerogel preparation, describes in detail the benchtop scale testbed and methods used to assess the catalytic activity of RSCE fabricated aerogels, and presents data on the catalytic ability of some promising aerogel chemistries.

The effects of reduced fuel injection pressure on the cold start performance of a GDI engine have been studied in a single-cylinder, optically-accessible research engine. Two Delphi Automotive Systems DI-G injectors, with included spray cone angles of 60° and 80° respectively, were studied. Both injectors are designed to operate at a nominal fuel line pressure of 10 MPa. For the study they were operated at several fuel feed pressures between 10 MPa and 2 MPa. Two start of injection timings (50° and 100° ATDC) were examined. Cold start performance was characterized by measurements of the GIMEP, COV of GIMEP, and total engine out UHCs. Simultaneous Planar Laser Induced Fluorescence (PLIF) and Mie Scattering images of the fuel spray were used to observe spray penetration, mixing, and in-cylinder fuel distribution throughout the intake and compression strokes. Ultimately these images were used to explain observed performance differences.

Experiments have been conducted in a laminar flow system and in a research engine to investigate the effect of additives on the combustion of gasoline-like fuels. The purpose of the laminar system is to enable rapid screening of additives to determine which, if any, have an enhancing effect on the early stages of combustion, especially under conditions of poor fuel vaporization which exist during cold-start in a spark ignited engine and which make flame propagation difficult to start and sustain. The base fuel used in the laminar and engine systems was a 9 component mixture formulated to simulate those components of gasoline expected to be present in the vapor phase in the intake system of an engine under cold-start conditions. In the laminar system, the pre-mixed, pre-vaporized fuel-air mixture is ignited and a time history of the combustion generated, hydroxyl radical chemiluminescence is recorded.

A Laser Induced Fluorescence (LIF) based technique has been employed to examine the transient fuel film behavior on an intake valve during cold start of a PFI engine. Fluorescence from a tracer in the fuel was collected through a Borescope and imaged onto a CCD camera, providing a 2-D image of the fuel film on the valve. The average intensity of the fluorescence, over a Region of Interest (ROI), was taken to be proportional to the total amount of fuel present in the film. Images were collected (at a fixed crank angle) on every second engine cycle, resolving changes in the fuel film during the cold start transient. Changes in the fuel film were resolved within a cycle by collecting images at varying crank angles during successive experiments. Results from four fuel mixtures are reported. Two simulated “single component fuels” one with a higher volatility (HV) and one with a lower volatility (LV), were examined.

In recent years general merchandise and hardware stores have been marketing devices to be inserted in the power supply of refrigerators and other motor driven appliances that are advertised as a technology to reduce electric energy use and cost. The purpose of this research was to procure and test one of these devices. The testing included examining how the device modifies the standard 60 cps and sinusoidal voltage power supply and then to determine the corresponding change in electric power consumption by an induction motor as a function of mechanical load. The load is the product of motor speed which is nominally constant and the torque which is variable. The torque depends upon a combination of compressor characteristics and the low and high side pressures of the freon which is a function of the evaporator and condenser temperatures.

There have been estimates that the solid waste stream of municipal garbage could be converted to 5% of the total electric power requirement. In response to this potential many high capital cost incinerators have been installed around the country during the last two decades. Success has been marginal and many have been prematurely shut down because of technical problems and public concerns about emissions and potentially toxic ash. The alternative is to continue to use landfills, but to capture the methane that is produced by the decay of organic matter for the production of heat and electricity. Several such facilities have been installed in recent years and are demonstrating increasingly favorable operation. The purpose of this project was to research the techniques and technologies that are used to harness landfill gas, along with the related considerations of state and federal regulations and public health concerns from exposing the public to unburned and uncleaned landfill gas.

A characteristic of any electric or thermal storage technology is that it is easy to qualitatively describe the benefits, but it is very difficult to quantify the benefit and how a storage system should be best operated since operation is both site specific and requires forecasts of future electric, heating or cooling demand. Ice storage has the advantage of being able to absorb or release heat at a constant temperature of 32 F by using the abundant mass of water as the storage medium. There is no comparable substance that is available for constant temperature storage of space heat. Thus heat storage is typically done much less effectively by sensible heating or cooling of water. Thus, storing cold is more practical than strong heat. Thus, ice for air con-ditioning has been installed at several locations and has been proposed for the expansion of the chiller capacity at Union College to meet the increased demand from two new buildings.

An experimental study was conducted to investigate methanol autoignition including surface effects. Autoignition temperatures were determined for methanol using spherical, glass, constant volume bombs of various size, in order to assess the effects of changing the vessel surface-to-volume ratio on the minimum autoignition temperature and on the autoignition limits and ignition delays. Autoignition limit diagrams were constructed by determining the autoignition temperature for various methanol/oxygen/nitrogen mixtures. The diagrams were characterized by a minimum autoignition temperature occurring at a particular equivalence ratio, which was typically not stoichiometric. An empirical Arrhenius type expression for ignition delay was also developed and analyzed with respect to surface effects. This model was then compared with models used at higher temperatures.

The autoignition characteristics of ethanol were examined in the 667-743 K temperature range at one atmosphere. A closed static reactor testing facility, of the Le Chatelier type was employed in this study. The autoignition limits for two ethanol concentrations at varied oxygen-nitrogen concentrations are mapped out. At each fuel concentration the minimum autoignition temperature occurred at an equivalence ratio of 0.3. An Arrhenius-type expression for the ignition delay time was developed and yielded a global activation energy of 42.1 kcal/mol. Increases in ethanol and oxygen concentrations cause a decrease in ignition delay time. Ethanol concentrations proved to have a greater effect on the ignition delay times than did oxygen concentrations.

An experimental study was conducted to investigate the autoignition characteristics of methanol. Experimental conditions which were explored included temperatures in the range of 650-800 K, equivalence ratios of 0.2-17.0, 1 atm pressure, and reactor surface-to-volume ratios. S/V, of 0.6 cm−1″ and 0.48 cm−1. The ignition delay times were correlated with initial temperatures, methanol, and oxygen concentrations and fit to an Arrhenius type expression. The analysis resulted in a global activation energy of 55.2 kcal/mol and fuel and oxidizer concentration exponents of −0.98 and −0.13, respectively. Also, autoignition limit diagrams were developed which distinguish the regions of ignition and non-ignition, as well as show the effects of equivalence ratio and surface-to-volume ratio changes on minimum autoignition temperatures.

It has been shown that the ideal fuel burning engine, which is named the Wicks Cycle, can be implemented as a three process gas turbine cycle consisting of isothermal compression, heat addition and reversible adiabatic expansion to the ambient temperature as well as ambient pressure. However, such a cycle operating at typical fuel combustion temperatures requires excessive pressure ratios. This paper examines whether such a cycle, or a gas turbine cycle with compressor intercooling, may be a realistic bottoming cycle in a combined cycle plant, as an alternative to either existing practice steam cycles or to the proposed alternative Kalina Cycle.

Although electric vehicles have nearly a 100 year history, there is a dramatic new level of interest as a result of a combination of improved component technology, air pollution control legislation, and the resulting response and announcements by automobile manufacturers in the development of high performance electric vehicles. These performance announcements are typically in terms of range at a particular speed and acceleration. However, vehicles will operate over a wide range of conditions. This paper develops a mathematical model of an electric vehicle in terms of power and energy requirements and conversion components, and presents an equivalent circuit model of the batteries as a function of the charge condition, with the battery parameters obtained from charge-discharge testing, and demonstrates the use of this model to predict vehicle performance over a variety of driving and battery conditions.

A hypothetical residential building in Albany, New York with a structure heat loss of 870 Btu/hr-°F is considered. The energy requirements for heating such a house by different systems are investigated employing the bin method and a computer program. The systems whose performance are evaluated are: (1) air-to-air heat pump with electric resistance heating backup, (2) gas furnace, (3) oil furnace and (4) electric resistance baseboard. The yearly energy costs for operating these four systems are estimated and compared. It is found that the natural gas heating is the most economical and electric baseboard heating the most expensive. The heat pump is the second most economical with oil heating being very close third. These relative ratings may change if the cooling needs are taken into account, initial costs are amortized or unit energy costs vary.