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Alternative fuels based on biomass have typically been specified in ways which substantially limit allowable compositions. These specifications are unlike those for petroleum based fuels which include mixtures comprised of hundreds of different compounds. Such narrow biofuel specifications are clearly disadvantageous by restricting any flexibility of using different biofuels to minimize costs and offset price fluctuations. This paper focuses on critical performance criteria for diesel fuels and provides experimental data on several, non-conventional biofuels. Experimental data includes the physical properties and ignition delay times of new, lower cost sugar formulations. The objective of this work is to develop specifications on volumetric heating value, viscosity, and ignition properties as well as other properties for compression ignition biofuels. Proposed fuel specifications would not include compositions, thereby allowing a variety of feedstocks to be used.

The present paper aims at developing a general method to estimate integral and microtime scales of turbulent in-cylinder flow field in reciprocating engines. The ensemble average technique was used to compute the integral time scale from the single point time autocorrelation function, whereas the microtime scale, representative of the most rapid changes that occur in the fluctuation, was computed as the intercept of the parabola that matches the autocorrelation function at the origin. Further, the microtime scale was also estimated by spectral analysis through the energy spectral density function of the ensemble turbulent fluctuation and the results obtained by the two methods were compared. The procedures were applied to the tangential component of the instantaneous velocity data collected, at different engine speeds (1,000, 1,500, 2,000 rpm), within a motored d.i. diesel engine equipped with a re-entrant combustion chamber, using the Laser Doppler Anemometry (LDA) technique.

The purpose of this paper is to provide a summary of the US activity regarding the development of biodiesel specifications and to provide an update of the latest status and activity in the US. An ASTM Biodiesel Task Force was formed in 1994 to develop a US standard for biodiesel. Several iterations of the standard have occurred between biodiesel producers, engine manufacturers, and researchers and good agreement has been reached. The National Biodiesel Board and US biodiesel suppliers have adopted specifications based on the ASTM work. Recent approval was granted for the development of a provisional ASTM biodiesel standard which would be published by ASTM while additional data and approvals for a full ASTM standard (further field data test method precision and bias information and approval of the GC method for free and total glycerine) are occurring. Background - Biodiesel, a renewable diesel fuel substitute or blending stock, is currently being commercialized in the US.

A Cummins N14-410 diesel engine was operated on four fuels produced by blending Biodiesel (methyl tallowate) and no. 2 diesel fuel. Engine in-cylinder pressure data were collected at various engine speeds and used to evaluate the peak pressure, indicated mean effective pressure (IMEP), rate of change of pressure, rate of heat release, mass fraction of fuel burned, and charge temperature with respect to crank angle. Peak cylinder pressures for each fuel blend at all engine speeds were lower than peak pressure for no. 2 diesel fuel, the IMEP values for all fuel blends were less than that of no. 2 diesel fuel. The differences in IMEP values correlated with the differences in power output of the engine. The maximum rates of pressure rise for all fuel blends were less than for no. 2 diesel fuel. The rate of heat release decreased with increasing engine speed as well as, with the amount of methyl tallowate in the fuel blend.

The methyl esters of vegetable oils and animal fats, known as biodiesel, are receiving increasing attention as an alternative fuel for diesel engines. Although the production of biodiesel involves a relatively simple chemical process, there is potential for various contaminants to be present in the fuel. These contaminants include water, free glycerin, bound glycerin, alcohol, free fatty acids, soaps, catalyst, unsaponifiable matter and the products of oxidation. As interest in this fuel grows, quality standards and specifications are being developed. These standards place limits on the amounts of contaminants that may be present in biodiesel. The objective of this project was to develop a database of property data to provide a basis for setting realistic specification values for biodiesel. Small amounts of these various contaminants were added to biodresel and their impact on the properties and performance of the biodiesel was measured.

The combustion chamber deposit (CCD) forming tendency of gasoline components and detergents were investigated with laboratory tests ad engine dynamometer tests. In the dynamometer tests, the driving conditions under which fuels and detergents influence CCD formation were specified, and the effects of different gasoline components and detergent blends on CCD formation were examined. In the laboratory tests, the CCD forming process was investigated thoroughly [10]. The CCD forming tendency of aromatic compounds in gasoline were dependent not only on physical properties such as molecular weight, but also chemical structure (number or position of the alkyl substituents of aromatic molecules). As for oxygenates, engine dynamometer tests with MTBE blended gasoline yielded less CCD than the test without MTBE. The CCD forming tendency of detergents correlated with the thermal decompositon tendency of the detergent package and the concentration of the main agents.

Despite the many years of widespread use of the BMW Intake Valve Deposit (IVD) vehicle test, relatively little has been published quantifying the variation in the test procedure. This paper presents an analysis of the variability in the BMW test. Though results from 8045 km (8K; 5,000 mile) tests rather than 16090 km (16K; 10,000 mile) are highlighted due to the size of the available database and relative sensitivity of the data, analysis suggests that variation at 8K is representative of 16K variation. A square root transformation of average deposit weight at 8K, though more cumbersome than the more common log transformation, is found to be the most appropriate way to eliminate the dependence of variation on the absolute level of deposits. Within-car variation is found to account for over half of the test-to-test variation, contradicting the notion that car-to-car differences are the dominant source of variability.

Under hot transient conditions, the effects of gasoline properties, such as the research octane number (RON), the motor octane number (MON) and types of components on acceleration performance were investigated using four ‘Premium Gasoline Required Vehicles’ which are Japanese commercial vehicles equipped with knock sensors (KSs) and an electronic control unit (ECU) to prevent the engines from knocking. Regarding the fuel, two series of fuels were used. One of them {Primary Reference Fuel Series (PRF series)} was prepared to investigate the effectiveness of the octane number of PRF (ON). The other {Components Series (COMP series)} was prepared to investigate the effects of fuel components on the same. Fuels in the COMP series had almost the same RON level, which was almost equal to 90. In the PRF series, the acceleration performance of all vehicles were improved as ON increased.

Two fleets of thirty vehicles each were emissions tested in order to determine the effect of gasoline RVP reduction on tailpipe carbon monoxide (CO) emissions in Las Vegas and Los Angeles under conditions typical of winter CO exceedances in these two cities. The hypothesized emission reduction was confirmed for Las Vegas. However, for Los Angeles, the effect of RVP was questionable. The reason or reasons for this discrepancy between the two cities could not be completely resolved from this study. Detrimental emissions effects of reduced RVP under cold temperatures were found to be small and inconsequential.

The Northeast Area of the Postal Service recently completed an assessment of the environmental and economic impacts of deploying alternative fuel vehicles (AFVs) in Connecticut and Massachusetts. The study was conducted in accordance with procedures established by the President's Council of Environmental Quality (CEQ) to implement the National Environmental Policy Act (NEPA). This assessment produced a new computer model which is capable of comparing the environmental and economic impacts of various alternative fuel fleet options. The model was developed to be flexible in that it is able to compare various technologies and vehicle mixes and can also function as a data sensitivity testing program. The AFV assessment computer model provides the Postal Service with the tool needed to continually assess the environmental and economic impacts associated with rapidly changing AFV technologies.

This study conducts a series of numerical simulation to investigate systematically the improvement of power as well as thermal efficiency of the Miller cycle gas engines. Novel approach of the numerical simulation was to develop full chemical-kinetics methods to predict knocking phenomena for practical use. The method was successfully incorporated into the one-dimensional cycle simulator of the TSpark code developed by UMIST. The study predicted the performance of the Miller cycle, with particular attention to the improvement of thermal efficiency with higher expansion ratio and of engine power with lower compression ratio. Results show the Miller cycle substantially improves either efficiency or power by optimizing the compression and expansion ratios. Trade-off relation between the improved power and efficiency is evaluated.

The combustion characteristics of three gaseous fuels (hydrogen, methane and ethane) in a direct-injection stratified-charge single-cylinder engine with a centered square head-cup operated at 800 rpm (compression ratio = 10.8, squish ratio = 75%, nominal swirl ratio = 4) were studied to assess the extent to which the combustion is controlled by turbulent mixing, laminar mixing and chemical kinetics. The injection of gaseous fuels was via a Ford AFI injector, originally designed for the air-forced injection of liquid fuel. Pressure measurements in the engine cylinder and in the injector body, coupled with optical measurements of the injector poppet lift and shadowgraph images of the fuel jets provided both quantitative and qualitative information about the in-cylinder processes. To make the cases comparable, the total momentum of the fuel jets and the total heat released by the three fuels was kept the same (equivalence ratio = 0.316, 0.363, 0.329 for H2, CH4 and C2H6, respectively).

This paper discusses the gas-phase reaction mechanisms for removal of NOx in a plasma. The effect of oxygen content on the competition between the reduction and oxidation processes is discussed. The effect of the electron kinetic energy distribution on the radical production and subsequent chemistry is then discussed in order to predict the best performance that can be achieved for NOx reduction using the plasma alone. The fundamental limit on the minimum electrical energy consumption that will be required to implement NOx reduction in any type of plasma reactor is established.

Increases in efficiency may be possible by a new technique for non-thermal plasma aftertreatment of exhaust gases. The new technique involves very short risetimes (40ps) high frequency (5Ghz) high power bursts of low duty factor microwaves to generate a dielectric barrier discharge. The technique is illustrated in the simplified example of the dissociation of NO in N2. Electric field distributions and enhancing improvements are briefly described for a number of configurations. The technique is meant to be used in conjunction with material catalyst and can, for a class of catalysts, cause a significant reactivity on the catalyst surface.

The effect of natural gas composition on ignition delay has been investigated numerically by using detailed and reduced chemical kinetic mechanisms. Three different blends of natural gas have been analyzed at pressures and temperatures that are typical of top dead center conditions in compression ignition engines. The predicted ignition delay shows a decrease with temperature in an Arrhenius manner and has a first order dependence on pressure. Similar trends have been observed by Naber et al. [1] in their experimental study of natural gas autoignition in a bomb. It is shown that two kinetic mechanisms (GRI-Mech 1.2 and reduced set DRM22) are best capable of predicting the ignition delay of natural gas under compression ignition conditions. The DRM22 mechanism has been chosen for further studies as t involves lower computational costs compared to the full GRI-Mech 1.2 mechanism.

The destruction of low concentrations (<600 ppm) of nitric oxide using a low-temperature, dielectric barrier/packed-bed corona reactor has been studied. We compare the chemistry and energy efficiencies observed using various packing materials in warm moist air under oxidative (lean-burn) conditions. Measurements of NO and NOx removal in the effluent gas were made as a function of energy dissipated in the reactor. Changes in the observed fate of NO as a function of the packing material are discussed.

This paper presents a concept for enhancing catalytic removal of pollutant species from an exhaust stream by placing placing the plasma adjacent to the catalyst surface. Model calculations of the behavior of the electron energy distribution function (EEDF), which influences the chemistry and ionization levels near the surface, are performed and analyzed. Preliminary experiments attempting to reduce these theoretical ideas to practice in N2/NO mixtures, are discussed. Although removal of NO is observed, this is due to gas phase effects alone. The present experimental arrangement is not able to produce the requisite conditions outlined by theory to enact plasma-enhanced catalysis.

Worldwide concern about combustion chamber deposits (CCDs) has increased from the viewpoint of fuel and additives technology, which has been developed for the cleaning of intake valve deposits (IVDs), intake port deposits and injector deposits. The research effort described here, focused on the differences between CCDs and IVDs in terms of quality based on analyses of CCDs and IVDs collected from used vehicles from the Japanese market. The CCDs and IVDs were characterized according to weight, benzene-solubles and sulfated ash. Since the sulfated ash in CCDs is a key to understanding the effect of engine oil on CCD formation, the relationship between CCDs and the sulfated ash in CCDs was evaluated under the two typical conditions on a 2.0L engine testing bench. Based on the results, the gasoline-related and oil-related factors were estimated for these conditions. Moreover, the effect of CCDs on exhaust emissions was investigated in a 2.2L vehicle.

Most automotive multigrade oils contain high molecular weight polymeric viscosity index improvers (VII's) and are, to a greater or lesser extent, viscoelastic fluids. For many years the effect of multigrade oil viscoelasticity on journal bearing lubricant load bearing capacity (LBC), (and implicitly minimum oil film thickness) has been a vexed question. The work described in this paper provides experimental evidence that a significant enhancement of journal bearing LBC over that generated by isoviscous Newtonian (single grade) oils can be achieved by the use of multigrade oils under simulated realistic in-senice engine conditions. This effect only occurs under operation at high eccentricity ratios. At lower eccentricity ratios no enhancement in LBC could be found. Examination of the effect of lubricant piezoviscosity on LBC failed to account for the load bearing enhancement phenomenon.

The discovery of Constrained Geometry Catalysts (CGC) for production of polyolefins allows one to make new polyolefins in a solution process. CGCs have a single active site for polymerization, and the bridged nature of the monocyclopentadienyl titanium complex allows facile incorporation of alpha olefins into random ethylene copolymers that are characterized by narrow molecular weight distributions and narrow comonomer distributions. In this paper, olefin copolymers (OCPs) of ethylene with propylene and octene comonomers produced with constrained geometry catalyst are described, and their behavior as viscosity index improvers in oil solutions is examined. A wide range of amorphous and semicrystalline OCPs have been produced and characterized. Crystallinity was measured by DSC, and molecular weights (Mw) were determined by GPC.