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We assessed the engine-out emissions of an ultra-low sulfur diesel (ULSD) and a neat hydrogenated vegetable oil (HVO) from a light-duty diesel truck equipped with common rail direct injection. The vehicle was tested at least twice on each fuel using the LA-92 drive cycle and at steady-state conditions at 30 mph and 50 mph at different loads. Results showed reductions in the engine-out total hydrocarbon (THC), carbon monoxide (CO), nitrogen oxide (NOx), and particulate emissions with HVO. The reductions in soot mass, solid particle number, and particulate matter (PM) mass emissions with HVO were due to the absence of aromatic and polyaromatic hydrocarbon compounds, as well as sulfur species, which are known precursors of soot formation. Volumetric fuel economy, calculated based on the carbon balance method, did not show statistically significant differences between the fuels.

Interest in natural gas as a fuel for light-duty transportation has increased due to its domestic availability and lower cost relative to gasoline. Natural gas, comprised mainly of methane, has a higher knock resistance than gasoline making it advantageous for high load operation. However, the lower flame speeds of natural gas can cause ignitability issues at part-load operation leading to an increase in the initial flame development process. While port-fuel injection of natural gas can lead to a loss in power density due to the displacement of intake air, injecting natural gas directly into the cylinder can reduce such losses. A study was designed and performed to evaluate the potential of natural gas for use as a light-duty fuel. Steady-state baseline tests were performed on a single-cylinder research engine equipped for port-fuel injection of gasoline and natural gas, as well as centrally mounted direct injection of natural gas.

Gasoline direct injection (GDI) engines have improved thermodynamic efficiency (and thus lower fuel consumption) and power output compared with port fuel injection (PFI) and their penetration is expected to rapidly grow in the near future in the U.S. market. In addition, the use of alternative fuels is expanding, with a potential increase in ethanol content beyond the current 10%. Increased emphasis has been placed on butanol due to its more favorable fuel properties, as well as new developments in production processes. This study explores the influence of mid-level ethanol and iso-butanol blends on criteria emissions, gaseous air toxics, and particulate emissions from two wall-guided gasoline direct injection passenger cars fitted with three-way catalysts. Emission measurements were conducted over the Federal Test Procedure (FTP) driving cycle on a chassis dynamometer.

A model process to produce dimethylether (DME) from natural gas (NG) was simulated in a one-pass mode (no material recycle), assuming steady-state and chemical and physical equilibrium. NG conversion to synthesis gas (syngas) via steam reforming resulted in stoichiometric numbers of 2.97 along with vapor mole fraction extremes for carbon dioxide, methane, and water. These concentrations formed an eight-trial simulation grid of syngas compositions. Simulation of DME production was performed in a dual reactor configuration with methanol formation as the intermediate compound. Solutions resulting from the subsequent adiabatic dehydration of the methanol-rich phase showed a consistent DME composition (88%). The resulting solutions and unreacted syngas streams from simulation were examined for applicability to a dual-fuel NG/DME CI engine.

Although various legislation and regulations have been adopted to promote the use of alternative-fuel vehicles for curbing urban air pollution problems, there is a lack of systematic comparisons of emission control cost-effectiveness among various alternative-fuel vehicle types. In this paper, life-cycle emission reductions and life-cycle costs were estimated for passenger cars fueled with methanol, ethanol, liquified petroleum gas, compressed natural gas, and electricity. Vehicle emission estimates included both exhaust and evaporative emissions for air pollutants of hydrocarbon, carbon monoxide. nitrogen oxides, and air-toxic pollutants of benzene, formaldehyde, 1,3-butadiene, and acetaldehyde. Vehicle life-cycle cost estimates accounted for vehicle purchase prices, vehicle life, fuel costs, and vehicle maintenance costs.

The objective of this research was to study the effects of a CCRT®, henceforth called Diesel Oxidation Catalyst - Catalyzed Particulate Filter (DOC-CPF) system on particulate and gaseous emissions from a heavy-duty diesel engine (HDDE) operated at Modes 11 and 9 of the old Environmental Protection Agency (EPA) 13-mode test cycle Emissions characterized included: total particulate matter (TPM) and components of carbonaceous solids (SOL), soluble organic fraction (SOF) and sulfates (SO4); vapor phase organics (XOC); gaseous emissions of total hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NOx), nitric oxide (NO) and nitrogen dioxide (NO2), oxygen (O2) and carbon dioxide (CO2); and particle size distributions at normal dilution ratio (NDR) and higher dilution ratio (HDR). Significant reductions were observed for TPM and SOL (>90%), SOF (>80%) and XOC (>70%) across the DOC-CPF at both modes.

The objective of this research was to study the effect of a catalyzed particulate filter (CPF) with a high loading of catalyst (50 gms/ft3) and ultra low sulfur fuel (ULSF -0.57 ppm of sulfur) on the emissions from a heavy duty diesel engine. The particulate emissions were measured using two different analytical methods, i.e., the gravimetric method and the thermal optical method (TOM). The results from the two different methods of analyses were compared. The experiments were performed at four different operating conditions chosen from the old Environmental Protection Agency (EPA) 13-mode test cycle. A 1995 Cummins M11 heavy-duty engine with manually controlled exhaust gas recirculation (EGR) was used to perform the emission characterization experiments. The emission characterization included total particulate matter (TPM), which is composed of the solids (SOL), soluble organic fractions (SOF) and sulfates (SO4) analyzed using the gravimetric method.

Turbocharging, in addition to increasing an engine's power output, can be effectively used to maintain exhaust emission levels while improving fuel economy. This paper presents the emission and performance results obtained from a turbocharged multicylinder spark ignition engine with thermal reactors and exhaust gas recirculation (EGR) operated at steady-state, part-load conditions for four engine speeds. When comparing a turbocharged engine to a larger displacement naturally aspirated engine of equal power output, the emissions expressed in grams per mile were relatively unchanged both with and without EGR. However, turbocharging provided an average of 20% improvement in fuel economy both with and without EGR. When comparing the turbocharged and nonturbocharged versions of the same engine without EGR at a given load and speed, turbocharging increased the hydrocarbon (HC) and carbon monoxide (CO) emissions and decreased oxides of nitrogen (NOx) emissions.

A new diesel van with a reference weight of 1661 kg and a pre-chamber engine with a displacement of 2400cc was tested on a chassis dynamometer. The fuel consumption and emissions of carbon monoxide, unburned hydrocarbons, nitrogen oxides, carbon dioxide, particulate matter and associated organic material (SOF) as well as PAH (Polycyclic Aromatic Hydrocarbons) were measured under different driving conditions. The driving patterns used were recorded with a chase car at real traffic conditions on several roads in Copenhagen. The emissions were measured using different kind of diesel fuels as well as RME and biodiesel. CO, CO2, HC, and NOx levels generally decreased with increasing average speed of the driving cycle for all fuels tested. Cold start emissions were generally higher than for warm start.

Engine manufacturers have explored many routes to reducing the emissions of harmful pollutants and conserving energy resources, including development of after treatment systems to reduce the concentration of pollutants in the engine exhaust, using alternative fuels, and using alternative fuels with after treatment systems. Liquefied petroleum gas (LPG) is one alternative fuel in use and this paper will discuss emission measurements for several LPG vehicles. Regulated emissions were measured for five school buses, one box truck, and two small buses over a cold start Urban Dynamometer Driving Schedule (CS_UDDS), the Urban Dynamometer Driving Schedule (UDDS), and the Central Business District (CBD) cycle. In general, there were no significant differences in the gas phase emissions between the UDDS and the CBD test cycles. For the CS-UDDS cycle the total hydrocarbons and non-methane hydrocarbon emissions are higher than they are from the UDDS cycle.

The primary objective of this study was to evaluate the impact of three different biodiesel feedstocks on emissions compared to a baseline CARB ULSD with two heavy-duty trucks equipped with and without aftertreatment technologies. The biodiesels included a soybean oil methyl ester (SME), a waste cooking oil methyl ester (WCO), and a methyl ester obtained from animal fat (AFME), blended at a 50% level by volume with the CARB diesel. The vehicles were equipped with a 2010 Cummins ISX-15 engine with a selective catalytic reduction (SCR), diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF) and with a 2002 Cummins ISX-450 engine. Both vehicles were tested over the Urban Dynamometer Driving Schedule (UDDS) on a heavy-duty chassis dynamometer. For this study, nitrogen oxides (NOx), carbon monoxide (CO), carbon dioxide (CO2), total hydrocarbons (THC), methane (CH4), non-methane hydrocarbons (NMHC), and particulate matter (PM) were measured.

Steady-state, transient and dithering characteristics of emission conversion efficiencies of three-way catalysts on natural gas IC engine were investigated experimentally on a single-cylinder CFR engine test bench. Steady-state runs were conducted as references for specific engine emission levels and corresponding catalyst capacities. The steady-state data showed that conversion of HC will be the major problem since conversion of HC was effective only for a very narrow range of exhaust mixture. Unsteady exploration runs with both lean-to-rich and rich-to-lean transitions were conducted. These results were interpreted with a time scale analysis, according to which a qualitative oxygen storage model was proposed featuring the difference between oxygen absorption and desorption rates on the palladium catalysts.

Hydrogen exhibits the notable attribute of lacking carbon dioxide emissions when used in internal combustion engines. Nevertheless, hydrogen has a very low energy density per unit volume, along with large emissions of nitrogen oxides and the potential for backfire. Thus, stratified charge combustion (SCC) is used to reduce nitrogen oxides and increase engine efficiency. Although SCC has the capacity to expand the lean limit, the stability of combustion is influenced by the mixture formation time (MFT), which determines the equivalence ratio. Therefore, quantifying the equivalence ratio under different MFT is critical since it determines combustion characteristics. This study investigates the viability of using a Laser Induced Breakdown Spectroscopy (LIBS) for measuring the jet equivalence ratio. Furthermore, study was conducted to analyze the effect of MFT and the double injection parameter, namely the dwell time and split ratio, on the equivalence ratio.