John Nuszkowski

Neat fuel influence on biodiesel blend emissions

Abstract The emissions of oxides of nitrogen (NO x ) from biodiesel blended fuels reported in the literature vary from an NO x increase to an NO x decrease relative to the neat petroleum diesel fuel (PDF). To explain these NO x differences, three PDFs with varying fuel properties were admixed with a neat soy-derived biodiesel at 10 per cent and 20 per cent volume ratios and evaluated using a heavy-duty diesel engine exercised over transient and steady-state cycles. The PDFs with ‘low’ and ‘medium’ cetane numbers led to a change in combustion phasing when blended with the neat biodiesel, resulting in reduced NO x emissions at low engine power. The B100 blended with the ‘high’-cetane-number PDF showed minimal change in combustion phasing and resulted in an NO x increase at all engine loads. The derived peak in-cylinder gas temperature variation correlated with the brake-specific NO x emissions indicating that the thermal NO x formation responds to the addition of biodiesel. The biodiesel blends had an NO x —particulate matter trade-off, also suggesting a thermal NO x effect. The increase in NO x emissions of the biodiesel blends also had a strong correlation with the level of saturated hydrocarbons at high engine power.

Evaluation of the NOx emissions from heavy-duty diesel engines with the addition of cetane improvers

Abstract The exhaust emissions from heavy-duty diesel engines (HDDEs) contribute to the degradation of ambient air quality; therefore, environmental agencies have created stringent emissions standards. Since the implementation of these standards, overall engine and fuel technology improvements have created a significant reduction in emissions. This study was completed in order to evaluate oxides of nitrogen (NO x ) emissions from fuels with and without cetane-improving additives in recent and early production electronically controlled HDDEs. Five engines spanning the model years from 1991 to 2004 were tested using the Federal Test Procedure (FTP) dynamometer cycle with both petroleum-based diesel and B20 as the neat fuel. It was found that the additives had the most impact on reducing emissions at low engine powers, but the engine power range with an NO x benefit varied between engines. The cetane improvers were found only to reduce NO x below a cylinder gas density of 35kg/m3 at top dead centre. The lower compression ratio of the 1992 DDC S60 engines reduced the cylinder gas density and provided a larger optimal operating range for the cetane improvers. The cetane improvers reduced NO x at low engine powers and cylinder gas density for the B20 fuel but were less effective than for the neat petroleum fuels.

An Investigation of NO2 Emissions from a Heavy-Duty Diesel Engine Fumigated with H2 and Natural Gas

The oxides of nitrogen (NOx) emissions of diesel engines consist of nitric oxide (NO) and nitrogen dioxide (NO2). Although emitted at small amounts, NO2 has higher toxicity and causes more health and environmental issues than NO. This research investigates the impact of the addition of hydrogen (H2), natural gas (NG), and engine load on NO2 emissions from a heavy-duty diesel engine converted to operate using dual fuel combustion mode. The substitution of a small amount of H2 or NG for the diesel fuel substantially increased NO2 emissions, but had a very mild impact on the combustion process. In comparison, the substitution of a large amount of H2 and NG for the diesel fuel dramatically altered the combustion process and produced more NO2 than the diesel-only operation, but produced less NO2 than the addition of a small amount of H2 and NG. A preliminary analysis revealed a firm correlation between NO2 emissions and the emissions of the unburned H2 or CH4, and their relative emissions. The importance of the unburned fumigation fuels in enhancing NO2 formation in dual fuel engines was also supported by the data reported in the literature. The portion of supplemental fuels entrained into the diesel spray plume and simultaneously burned with the diesel fuel may not contribute to the increased NO2 emissions from dual fuel engines.

Atmospheric Emissions from a Passenger Ferry with Selective Catalytic Reduction

Abstract The two main propulsion engines on Staten Island Ferry Alice Austen (Caterpillar 3516A, 1550 hp each) were fitted with selective catalytic reduction (SCR) aftertreatment technology to reduce emissions of oxides of nitrogen (NOx). After the installation of the SCR system, emissions from the ferry were characterized both pre- and post-aftertreatment. Prior research has shown that the ferry operates in four modes, namely idle, acceleration, cruise, and maneuvering modes. Emissions were measured for both engines (designated NY and SI) and for travel in both directions between Manhattan and Staten Island. The emissions characterization used an analyzer system, a data logger, and a filter-based particulate matter (PM) measurement system. The measurement of NOx, carbon monoxide (CO), and carbon dioxide (CO2) were based on federal reference methods. With the existing control strategy for the SCR urea injection, the SCR provided approximately 64% reduction of NOx for engine NY and 36% reduction for engine SI for a complete round trip with less than 6.5 parts per million by volume (ppmv) of ammonia slip during urea injection. Average reductions during the cruise mode were 75% for engine NY and 47% for engine SI, which was operating differently than engine NY. Reductions for the cruise mode during urea injection typically exceeded 94% from both engines, but urea was injected only when the catalyst temperature reached a 300 °C threshold pre- and postcatalyst. Data analysis showed a total NOx mass emission split with 80% produced during cruise, and the remaining 20% spread across idle, acceleration, and maneuvering. Examination of continuous NOx data showed that higher reductions of NOx could be achieved on both engines by initiating the urea injection at an earlier point (lower exhaust temperature) in the acceleration and cruise modes of operation. The oxidation catalyst reduced the CO production 94% for engine NY and 82% for engine SI, although the high CO levels during acceleration did cause analyzers to over-range. No clear, quantitative conclusions could be made regarding the effects of the SCR on PM

In-Use Heavy-Duty Diesel Emissions Measurement Using an Air-to-Fuel Ratio Derived Exhaust Flow Rate

Emissions produced by internal combustion engines during laboratory testing have been shown to not fully represent real world applications. Raw emissions measurements have aided the study of vehicle emissions resulting from in-use applications. In-use emissions measurements may be cumbersome; being that direct measurement of exhaust flow rate will often require that the vehicle exhaust system be modified. This paper investigated the feasibility of substituting exhaust air-to-fuel ratio and ECU fuel flow rates for the inferred measurement of exhaust flow rates. The air-to-fuel ratio for a diesel application was solved from the measured raw emissions of CO2 , O2 , and NOx. A 2002 Ford F-650, powered by a 2002 Cummins ISB diesel engine, was fitted with an Annubar™ exhaust flow rate measurement system (averaging pitot tube) in order to directly measure continuous exhaust flow rates. Concurrently, exhaust flow rates were estimated from air-to-fuel ratio, while “theoretical” exhaust flow rates were derived from engine speed, intake air density, and assumed volumetric efficiency. These surrogate measurements of exhaust flow rates were then compared with the direct measurements of flow rates obtained by the Annubar™ system. Fuel consumption estimates based on the air-to-fuel ratio derived exhaust flow rate and CO2 , theoretical exhaust flow rate and CO2 , and measured exhaust flow rates and CO2 were then compared with reported ECU fueling rates over the entire test and during NTE events. An error analysis was performed on the air-to-fuel ratio exhaust flow rate equation to quantify uncertainty resulting from the measurements and assumed parameters. The results showed that the air-to-fuel ratio derived exhaust flow rates compared well with the measured exhaust flow rates and the theoretical exhaust flow rates with an R2 value of 0.982 and 0.986, respectively. During highly transient events and motoring conditions, the air-to-fuel ratio derived exhaust flow rates were inaccurate due to analyzer response and zero fueling conditions, respectively. However, during steadier operation, the air-to-fuel ratio derived exhaust flow rate compared to the measured exhaust flow rate and the theoretical exhaust flow rate within 3.5% and 1.9%, respectively. Overall measurement uncertainty was most affected by the CO2 analyzer at high AFRs. The resulting fuel consumptions from AFR derived exhaust flow rate, theoretical exhaust flow rate, and MEMS exhaust flow rate compared to within 2% of each other. The ECU fuel consumption was 5–7% higher than the MEMS, AFR derived, and theoretical.Copyright

Increasing the on-road fuel economy by trailing at a safe distance:

Energy is a driving force for automotive applications. Reducing the energy demand of the vehicle is one method of increasing the fuel economy of a vehicle. Heavy-duty commercial vehicles have large frontal areas that provide large amounts of aerodynamic drag at highway speeds. Reducing the aerodynamic drag lowers the engine demand and therefore increases the fuel economy of the vehicle. This study tested the fuel economy and the front air velocity of a 10.7 m box truck trailing another box truck by distances of 3.1 times the truck length, 4.7 times the truck length, and 6.3 times the truck length at a highway speed of 28 m/s. The distance of 6.3 times the vehicle length was considered ‘safe’ for trailing another vehicle, whereas the distances of 3.1 times the truck length and 4.7 times the truck length were not considered safe by the United States Fire Administration. The results showed significant reductions in the air velocity in front of the trailing vehicle of 8.5%, 6.5%, and 3.8% for trailing distances of 3.1 times the vehicle length, 4.7 times the vehicle length, and 6.3 times the vehicle length respectively. The fuel economy of the trailing truck increased significantly by 7.4–8.0%, 8.2–9.0%, and 6.5%–7.7%, for trailing distances of 3.1 times the vehicle length, 4.7 times the vehicle length, and 6.3 times the vehicle length respectively. Based on a road load analysis, these fuel economy improvements indicated a reduction in the drag coefficient of the trailing vehicle of 8–10%. Therefore, a box truck trailing another box truck at a safe distance results in a reduction in the aerodynamics drag and a significant increase in the fuel economy.

Calorific value, flash point and cetane number of biodiesel from cotton, jatropha and neem binary and multi-blends with diesel

ABSTRACT The calorific value, flash point and cetane number were investigated for binary and multi-blends of biodiesel from cotton, jatropha and neem with diesel. A binary blend is a fuel mixture comprising biodiesel from one feedstock and diesel, while a multi-blend consists of biodiesel from two or more feedstocks and diesel fuel. Blends were made of B5, B10, B15, B20, B25 and B30 for binary blends of each biodiesel, and a replication of those blend levels for the mixed blends of cotton, neem and jatropha with fossil diesel. The calorific value of the biodiesel/diesel samples was measured using a bomb calorimeter, the flash point was determined by the ASTMD93 method using a Pensky–Martens closed cup tester and the cetane number was determined using a portable cetane/octane meter. It was established that most of the fuel samples have heating values above the American Society for Testing and Materials (ASTM) minimum and close to that of petro-diesel. All 28 fuel samples are consistent with the ASTM standards for flash point and cetane number, they are devoid of carbon deposits and inferior cooking in the CI engines, and they have the shortest ignition delay when burned in the CI engines; hence, they are suitable for use in CI engine operations. Statistical analyses of the experimental data carried out using SPSS software indicate that the data contributed equally in each category to all of the properties, and there are no significant differences between the experimental values.

Number Concentration and Size Distributions of Nanoparticle Emissions during Low Temperature Combustion using Fuels for Advanced Combustion Engines (FACE)

Concentration and Size Distributions of Nanoparticle Emissions during Low Temperature Combustion using Fuels for Advanced Combustion Engines (FACE)