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An experimental study of the effects of partially-oxidized biodiesel fuel on the degradation of fresh fuel was performed. A blend of soybean oil fatty acid methyl esters (FAMEs) in petroleum diesel fuel (30% v:v biodiesel, B30) was aged under accelerated conditions (90°C with aeration). Aging conditions focused on three different degrees of initial oxidation: 1) reduced oxidation stability (Rancimat induction period, IP); 2) high peroxide values (PV); and 3) high total acid number (TAN). Aged B30 fuel was mixed with fresh B30 fuel at two concentrations (10% and 30% m:m) and degradation of the mixtures at the above aging conditions was monitored for IP, PV, TAN, and FAME composition. Greater content of aged fuel carryover (30% m:m) corresponded to stronger effects. Oxidation stability was most adversely affected by high peroxide concentration (Scenario 2), while peroxide content was most reduced for the high TAN scenario (Scenario 3).

Spray angle and penetration length data were taken under cold start conditions for a Direct Injection Spark Ignition engine to investigate the effect of transient conditions on spray development. The results show that during cold start, spray development depends primarily on fuel pressure, followed by Manifold Absolute Pressure (MAP). Injection frequency had little effect on spray development. The spray for this single hole, pressure-swirl fuel injector was characterized using high speed imaging. The fuel spray was characterized by three different regimes. Regime 1 comprised fuel pressures from 6 - 13 bar, MAPs from 0.7 - 1 bar, and was characterized by a large pre-spray along with large drop sizes. The spray angle and penetration lengths were comparatively small. Regime 2 comprised fuel pressures from 30 - 39 bar and MAPs from 0.51 - 0.54 bar. A large pre-spray and large drop sizes were still present but reduced compared to Regime 1.

Droplet size and velocity measurements were taken under cold start conditions for a Direct Injection Spark Ignition engine to investigate the effect of transient conditions on spray development. The results show that during cold start, spray development depends primarily on fuel pressure, followed by Manifold Absolute Pressure (MAP). The spray for this single hole, pressure-swirl fuel injector was characterized using phase Doppler interferometry. The fuel spray was characterized by three different regimes. Regime 1 comprised fuel pressures from 6 - 13 bar, MAPs from 0.7 - 1 bar, and was characterized by a large pre-spray along with large drop sizes. The spray profile resembled a solid cone. Regime 2 comprised fuel pressures from 30 - 39 bar and MAPs from 0.51 - 0.54 bar. A large pre-spray and large drop sizes were still present but reduced compared to Regime 1. The spray profile was mostly solid. Regime 3 comprised fuel pressures from 65 - 102 bar and MAPs from 0.36 - 0.46 bar.

This paper presents a study performed in 10 vehicles available in Brazilian market where the drivability with ethanol and gasoline, also referred as gasohol were compared. The motivation for this work came from the constant competition of the automotive industry, where engineers are searching for ways to improve the quality of the products aiming the “best in class” drivability with the best cost efficiency. For the Brazilian market, a further complexity is added to the development and verification process, which is the need to design and verify the controls and calibration considering the two fuels available in the market, the ethanol and the gasoline. In order to determine how the drivability is impacted by the ethanol, the paper presents a study where the drivability data were generated using the objective drivability measurement system AVL-DRIVE™.

The lack of electrical conductivity on materials, which are used in automotive fuel systems, can lead to electrostatic charges buildup in the components of such systems. This accumulation of energy can reach levels that exceed their capacity to withstand voltage surges, which considerably increases the risk of electrical discharges or sparks. Another important factor to consider is the conductivity of the commercially available fuels, such as biodiesel, which contributes to dissipate these charges to a proper grounding point in automobiles. From 2013, the diesel regulation in Brazil have changed and the levels of sulfur in the composition of diesel were reduced considerably, changing its natural characteristic of promoting electrostatic discharges, becoming more insulating.

FTP emissions tests on a passenger vehicle equipped with a 1.8 L IDI turbo-charged diesel engine show that the mass emissions of particles decrease by (36±8)% when 16.6% dimethoxymethane (DMM) by volume is added to a diesel fuel. Particle size measurements reveal log-normal accumulation mode distributions with number weighted geometric mean diameters in the 80 - 100 nm range. The number density is comparable for both base fuel and the DMM/diesel blend; however, the distributions shift to smaller particle diameter for the blend. This shift to smaller size is consistent with the observed reduction in particulate mass. No change is observed in NOx emissions. Formaldehyde emissions increase by (50±25)%, while emissions of other hydrocarbons are unchanged to within the estimated experimental error.

Ported shroud compressor covers recirculate low momentum air near the inducer blade tips, and the use of these devices has traditionally been confined to extending the low-flow operating region at elevated rotational speeds for compressors on compression-ignition (CI) engines. Implementation of ported shrouds on compressors for spark-ignition (SI) engines has been generally avoided due to operation at pressure ratios below the region where ported shrouds improve low-flow range, the slight efficiency penalty, and the perception of increased noise. The present study provides an experimental investigation of performance and acoustics for a SI engine turbocharger compressor both with a ported shroud and without (baseline). The objective of implementing the ported shroud was to reduce mid-flow range broadband whoosh noise of the baseline compressor over 4-12 kHz.

A thermodynamic model has been utilised in the analysis of a SI engine operating with a divided charge stratification system. Such a charge stratification system divides the cylinder charge into two distinct regions: a combustible charge around the spark plug and a dilution charge beyond this. The model has been utilised to reveal differing effects of both dilution charge composition (EGR or air) and temperature upon the performance and emissions of such a stratified charge engine.

The deterioration of combustion stability as lean operating limits and misfire conditions are approached has been investigated experimentally. The study has been carried out on spark ignition engines with port fuel injection and four-valves-per-cylinder. Test conditions cover fully-warm and cold operation, and ranges of air/fuel ratio, exhaust gas recirculation rates and spark timing. An approximate method of calculating gas/fuel ratio is described. This is used to show that combustion stability, characterised by the coefficient of variation of i.m.e.p., is a function of calculated gas/fuel ratio and spark timing until near to the limit of stability. A rapid deterioration in stability and the onset of weak, partial burning occurs at a gas/fuel ratio between 24:1 and 26:1 under fully-warm operating conditions, and around one gas/fuel ratio lower under cold operating conditions.

Historically, fuel cost conscious customers have tended to purchase diesel passenger cars. However, with increasing competition from alternative fuels and lean burn and direct injection gasoline fuelled engines, diesel engined vehicles currently face tough challenges from the point of fuel economy and emissions. In gasoline engines, low viscosity friction modified oils have demonstrated their potential for reducing internal engine friction and thus improving fuel economy, without adversely effecting engine durability. These fuel economy improvements have led to the introduction of such a low viscosity friction modified 5W-30 oil as the initial and service fill for the majority of Ford products sold in Europe. The trend towards even lower viscosities continues. To assess the potential benefits and issues of moving to 5W-20 in diesel engines, a short pilot study has been conducted using a Ford 1.8l direct injection diesel engine.

Acoustic standing waves are excited in internal combustion chambers by both normal combustion and autoignition. The energy in these acoustic modes can be transmitted through the engine block and radiated as high-frequency engine noise. Using finite-element models of two different (four-valve and two-valve) production engine combustion chambers, the mode shapes and relative frequencies of the in-cylinder volume acoustic modes are calculated as a function of crank angle. The model is validated by comparison to spectrograms of experimental time-sampled waveforms (from flush-mounted cylinder pressure sensors and accelerometers) from these two typical production spark-ignited engines.

During the course of emissions and fuel economy (FE) testing, vehicles that are calibrated to meet Tier 3 emissions requirements currently must demonstrate compliance on Tier 3 E10 fuel while maintaining emissions capability with Tier 2 E0 fuel used for FE label determination. Tier 3 emissions regulations prescribe lower sulfur E10 gasoline blends for the U.S. market. Tier 3 emissions test fuels specified by EPA are required to contain 9.54 volume % ethanol and 8-11 ppm sulfur content. EPA Tier 2 E0 test fuel has no ethanol and has nominal 30 ppm sulfur content. Under Tier 3 rules, Tier 2 E0 test fuel is still used to determine FE. Tier 3 calibrations can have difficulty meeting low Tier 3 emissions targets while testing with Tier 2 E0 fuel. Research has revealed that the primary cause of the high emissions is deactivation of the aftertreatment system due to sulfur accumulation on the catalysts.

The sources of unburned hydrocarbon (UHC) emissions in direct injection stratified charge engines are presented. Whereas crevices in the combustion chamber are the primary sources of UHC emissions in homogeneous charge engines, lean quenching and liquid film layers dominate UHC emissions in stratified charge operation. Emissions data from a single cylinder engine, operating in stratified charge mode at a low speed / light load condition is summarized. This operating point is interesting in that liquid film formation, as evidenced by smoke emissions, is minimal, thus highlighting the lean quenching process. The effects of operating parameters on UHC emissions are demonstrated via sweeps of spark advance, injection timing, manifold pressure, and swirl level. The effects of EGR dilution are also discussed. Spark advance is shown to be the most significant factor in UHC emissions. A semi-empirical model for UHC emissions is presented based on the analysis of existing engine data.

The air-hybrid engine absorbs the vehicle kinetic energy during braking, puts it into storage in the form of compressed air, and reuses it to assist in subsequent vehicle acceleration. In contrast to electric hybrid, the air hybrid does not require a second propulsion system. This approach provides a significant improvement in fuel economy without the electric hybrid complexity. The paper explores the fuel economy potential of an air hybrid engine by presenting the modeling results of a 2.5L V6 spark-ignition engine equipped with an electrohydraulic camless valvetrain and used in a 1531 kg passenger car. It describes the engine modifications, thermodynamics of various operating modes and vehicle driving cycle simulation. The air hybrid modeling projected a 64% and 12% of fuel economy improvement over the baseline vehicle in city and highway driving respectively.

Accounting for more than 90% of the molecules and more than 75% of the mass [1], hydrogen is the most abundant element in the universe. Due to the small molecule size and high buoyancy, it is not available in it’s free form on Earth. In recent years, hydrogen has gained the attention of the automotive industry [2–12] as an environmentally friendly alternative fuel. As a fuel, hydrogen is unique - it is odorless, colorless, tasteless, and burns invisibly in sunlight. Detection solutions such as the odorants used in natural gas are not yet feasible for automotive hydrogen because the available additives can poison the fuel cell catalyst. Additionally, the lower flammability limit of hydrogen is lower, and the flammability range wider, than fuels such as gasoline [13]. Hydrogen detection and its concentration measurement is usually done using hydrogen concentration sensors [13].

Dimethyl ether (DME) is an alternative to diesel fuel for use in compression-ignition engines with modified fuel systems and offers potential advantages of efficiency improvements and emission reductions. DME can be produced from natural gas (NG) or from renewable feedstocks such as landfill gas (LFG) or renewable natural gas from manure waste streams (MANR) or any other biomass. This study investigates the well-to-wheels (WTW) energy use and emissions of five DME production pathways as compared with those of petroleum gasoline and diesel using the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET®) model developed at Argonne National Laboratory (ANL).