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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Low-Temperature Combustion of High Octane Fuels in a Gasoline Compression Ignition Engine

Gasoline Compression Ignition (GCI) has been shown as one of the advanced combustion concepts that could potentially provide a pathway to achieve cleaner and more efficient combustion engines. Fuel and air in GCI are not fully premixed as compared to homogeneous charge compression ignition (HCCI) which is a completely kinetic-controlled combustion system. Therefore, the combustion phasing can be controlled by the time of injection, usually post injection in a multiple-injection scheme, to mitigate combustion noise. Gasoline fuels ignite more difficult than Diesel. The autoignition quality of gasoline can be indicated by research octane number (RON). Fuels with high octane tend to have more resistance to auto-ignition, hence more time for fuel-air mixing. In this study, three fuels, namely, Aromatic, Alkylate, and E30, with similar RON value of 98 but different hydrocarbon compositions were tested in a multi-cylinder engine under GCI combustion mode. Considerations of EGR, start of injection (SOI), and boost were investigated to study the sensitivity of dilution, local stratification, and reactivity of the charge, respectively, for each fuel. Combustion phasing was kept constant during the experiments to the changes in ignition and combustion process before and after 50% of the fuel mass is burned. Emission characteristics at different levels of EGR and lambda were revealed for all fuels with E30 having the lowest filter smoke number (FSN) and was also most sensitive to the change in dilution. Reasonably low combustion noise (< 90 dB) and stable combustion (COVIMEP < 3%) were maintained during the experiments. The second part of this paper contains visualization of the combustion process obtained from endoscope imaging for each fuel at selected conditions. Soot radiation signal from GCI combustion were strong during late injection, and also more intense at low EGR conditions. Furthermore, soot/temperature profiles indicated only the high-temperature combustion period, while cylinder pressure-based heat release rate (HRR) showed a two-stage combustion phenomenon.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2021

A Review and Perspective on Particulate Matter Indices Linking Fuel Composition to Particulate Emissions from Gasoline Engines

Particulate matter (PM) indices - those linking PM emissions from gasoline engines to the composition and properties of the fuel - have been a topic of significant study over the last decade. It has long been known that fuel composition has a significant impact on particulate emissions from gasoline engines. Since gasoline direct injection (GDI) engines have become the market-leading technology, this has become more significant because the evaporative behavior of fuel increases in importance. Several PM indices have been developed to provide metrics describing this behavior and correlating PM emissions. In this article, 16 different PM indices are identified and collected - to the authors' knowledge, all of the indices are available at the time of writing. The indices are reviewed and discussed in the context of the information required to calculate them, as well as their utility. Additionally, the authors believe that there is a need for indices that provide both a detailed and robust correlation, as well as those that are less sophisticated yet sufficient for specific use cases. Future research is suggested to guide the technical community toward improvements in the indices' methods and equations for both high and low fidelity and high and low time investment.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2018

Measured and Predicted Vapor Liquid Equilibrium of Ethanol-Gasoline Fuels with Insight on the Influence of Azeotrope Interactions on Aromatic Species Enrichment and Particulate Matter Formation in Spark Ignition Engines

A relationship has been observed between increasing ethanol content in gasoline and increased particulate matter (PM) emissions from direct injection spark ignition (DISI) vehicles. The fundamental cause of this observation is not well understood. One potential explanation is that increased evaporative cooling as a result of ethanol's high HOV may slow evaporation and prevent sufficient reactant mixing resulting in the combustion of localized fuel rich regions within the cylinder. In addition, it is well known that ethanol when blended in gasoline forms positive azeotropes which can alter the liquid/vapor composition during the vaporization process. In fact, it was shown recently through a numerical study that these interactions can retain the aromatic species within the liquid phase impeding the in-cylinder mixing of these compounds, which would accentuate PM formation upon combustion. To better understand the role of the azeotrope interactions on the vapor/liquid composition evolution of the fuel, distillations were performed using the Advanced Distillation Curve apparatus on carefully selected samples consisting of gasoline blended with ethanol and heavy aromatic and oxygenated compounds with varying vapor pressures, including cumene, p-cymene, 4-tertbutyl toluene, anisole, and 4-methyl anisole. Samples collected during the distillation indicate an enrichment of the heavy aromatic or oxygenated additive with an increase in initial ethanol concentration from E0 to E30. A recently developed distillation and droplet evaporation model is used to explore the influence of dilution effects versus azeotrope interactions on the aromatic species enrichment. The results suggest that HOV-cooling effects as well as aromatic species enrichment behaviors should be considered in future development of predictive indices to forecast the PM potential of fuels containing oxygenated compounds with comparatively high HOV.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2019

Effects of Fuel Properties on Particle Number and Particle Mass Emissions from Lean and Stoichiometric Gasoline Direct Injection Engine Operation

Engine-out particle size distributions and soot mass emissions were measured from a gasoline direct injection (GDI) engine fueled by seven different gasoline formulations. Additionally, particle size distributions were simultaneously measured downstream of a catalyzed gasoline particulate filter (GPF) to determine the size resolved filtration efficiency. Stoichiometric, lean homogeneous, and lean stratified combustion modes were studied at four steady-state engine conditions. The particulate matter (PM) Index was calculated for each fuel as a function of the double bond equivalent and vapor pressure of the fuel components. There was generally poor correlation between particle number (PN)/PM mass emissions and the PM Index for steady state stoichiometric conditions with clean injectors, which emitted low particle concentrations. However, under high-load lean homogeneous conditions, there was good correlation between PN/PM mass emission and the PM Index, with the exception that the high ethanol content fuel produced significantly higher PM emissions than the other fuels. Under lean stratified conditions, most fuels produced similar particle size distributions and concentrations with the exception that the E50 fuel produced significantly lower concentrations than the other fuels. These results demonstrate the profound sensitivity of particle emissions from high ethanol content fuel to engine operating conditions. Additionally, these results show the predominant factor influencing particle formation is charge mixture formation, which fuel properties influence, but not as significantly as engine conditions. Here, the GPF reduced the tailpipe particle number concentrations by 60 - 95% and showed evidence of passive regeneration under higher load lean engine conditions (Temp>400°C, Lambda>1.3). Total PN filtration efficiencies ranged from ~60 % with a clean filter to greater than 95% with as little as 25 mg/L of soot loaded on the filter with a most penetrating particle size (MPPS) between 100 and 150 nm. The GPF results show that GPF regeneration can be achieved with the added fuel efficiency benefit of lean operation.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2021

Demonstration of Better than Diesel Efficiency and Soot Emissions using Gasoline Compression Ignition in a Light Duty Engine with a Fuel Pressure Limitation

Increasing regulatory demand to reduce CO2 emissions has led to a focus on advanced combustion strategy development to improve overall engine efficiency. Gasoline compression ignition (GCI) has been demonstrated by others to have the potential to meet future CO2 regulations and emissions while achieving comparable to better efficiency than conventional diesel compression ignition (DCI). Soot and NOx emissions are also reduced significantly by using gasoline instead of diesel in compression ignition engines due to differences in composition, fuel properties, and reactivity. In comparison with diesel fuel, gasoline has a higher volatility and more resistance to autoignition, therefore, its longer ignition delay time will allow for better mixing of the air-fuel charge before combustion. In this study, a GCI combustion system has been tested in a Hyundai 2.2L engine as part of a US Department of Energy funded project. A double-injection strategy was tested from mid-to-high loads (5-20 bar BMEP) and for engine speeds in the range of 1200-3000 rpm. Up to 43.4% brake thermal efficiency was achieved using the GCI mode versus 41% using DCI mode. The GCI mode has demonstrated two distinct strategies that work at different load ranges, partially premixed compression ignition (PPCI) and mixing-controlled compression ignition (MCCI). Overall, this study shows that for similar engine-out NOx levels, GCI mode had higher brake thermal efficiency than DCI with lower fuel pressure and EGR required.

02 PETROLEUM↗
DOE OSTI2021

Hydrothermal catalysis of waste greases into green gasoline, jet, and diesel biofuels in continuous flow supercritical water

Production of green gasoline, jet, and diesel biofuels from waste greases was achieved using a novel hydrothermal, continuous-flow catalytic process operating under supercritical water conditions, with recycled water the only added chemical. Thermally and chemically stable catalysts were explored to optimize yields of liquid biofuels and to minimize production of gases and acidic compounds. A 50:50 mixture of brown and yellow waste greases converted into 76.6 wt% liquid biocrude (BC); the remainder converted to water and gases. Less than 0.2% of the FS formed carbon char (mainly amongst catalyst particles). Various tubular reactors (Inconel, ® Hastelloy®, titanium, stainless) showed no interior defects, erosion, or mass loss after runs. Here, the titanium catalyst was fully recovered and regenerated back to its original potency. The BC was further refined into 28%, 48%, 20%, and 4 wt%, respectively for green gasoline, jet, diesel, and bunker. Biofuels were analyzed for compound class compositions and reaction mechanisms were proposed. The hundreds of identified fuel products (C3-C35) from processing oleic acid as a pure model compound were identified. The neat green gasoline and diesel biofuels along with a 50% green jet blend (with petroleum Jet A) were tested in appropriate spark ignition, turbine, and diesel engines at University of MN Engine Labs. Biofuels achieved 107.7%, 97.2%, and 101.3% engine power performance levels relative to petroleum fuels (91-Octane, Jet A, #2 Diesel) along with lower CO and pollutant emissions. Biofuels passed ASTM fuel specifications (D4814, D7566, D975) including mandated corrosion and low sulfur limits of all three biofuels.

09 BIOMASS FUELS↗
DOE OSTI2016

Passive SCR for lean gasoline NO X control: Engine-based strategies to minimize fuel penalty associated with catalytic NH 3 generation

Lean gasoline engines offer greater fuel economy than common stoichiometric gasoline engines. However, excess oxygen prevents the use of the current three-way catalyst (TWC) to control nitrogen oxide (NO X ) emissions in lean exhaust. A passive SCR concept, introduced by General Motors Global R&D, makes use of a TWC that is already onboard to generate NH 3 under slightly rich conditions, which is stored on the downstream SCR. The stored NH 3 is then used to reduce NO X emissions when the engine switches to lean operation. In this work, the effect of engine parameters, such as air-fuel equivalence ratio and spark timing, on NH 3 generation over a commercial Pd-only TWC with no dedicated oxygen storage component was evaluated on a 2.0-liter BMW lean burn gasoline direct injection engine. NO X reduction, NH 3 formation, and reductant utilization processes were evaluated, and fuel efficiency was assessed and compared to the stoichiometric engine operation case. We found air-fuel equivalence ratio to be one of the most important parameters in controlling the NH 3 production; however, the rich operation necessary for NH 3 production results in a fuel consumption penalty. The fuel penalty can be minimized by adjusting spark timing to increase rich-phase engine out NO X emissions and, thereby, NH 3 levels. Additionally, higher engine out NO X during engine load increase to simulate acceleration resulted in additional fuel savings. Ultimately, a 10% fuel consumption benefit was achieved with the passive SCR approach by optimizing rich air-fuel equivalence ratio and spark timing while also utilizing acceleration load conditions.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Catalytic partial oxidation reformation of diesel, gasoline, and natural gas for use in low temperature combustion engines

Onboard reforming has relevance to both conventional and advanced combustion concepts. Most recently, onboard reforming has been proposed to enable “Single-Fuel RCCI” combustion and therefore, this paper explores catalytic partial oxidation reforming of three potential transportation-relevant fuels: gasoline, diesel, and natural gas. Reformation is performed at two pressure levels (between 15 and 60 psig) for each parent fuel for equivalence ratios ranging from 3.7 to 7.6 and the gaseous reformate mixtures are characterized with gas chromatography. The percentage of diesel oxidized during reformation is similar across all of the equivalence ratios. However, the percentage of gasoline and natural gas oxidized during reformation decreased with increasing equivalence ratio. The energy released during the reformation process is also calculated and presented for each gaseous reformate fuel. The lower heating value of every reformate fuel is lower than 20% of their respective parent fuel, due to the high concentration of inert gases (mostly nitrogen) in the reformate fuel mixtures. Two reformed fuels for each parent fuel were then selected to study their autoignition characteristics using HCCI combustion on a Co-operative Fuel Research (CFR) engine. The equivalence ratio is maintained at 0.31 and the combustion phasing was held constant by varying the intake temperature. Although the equivalence ratio is constant, the input energy from the different reformate fuels is not constant due to the component concentrations in the fuel. The gaseous reformate fuels are then compared to gasoline, natural gas, and the primary reference fuels in HCCI to determine an effective Primary Reference Fuel (PRF) number or effective octane rating for each gaseous reformate fuel. The effective octane rating for the gaseous reformate fuels fell slightly above the PRF number scale at an effective octane number of ~110.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2018

Sooting tendencies of co-optima test gasolines and their surrogates

Here, this study characterized the sooting tendencies of a set of gasolines and their surrogates using both experimental and computational methods. Sooting tendency was defined in terms of the soot yield when 1000 ppm of the test fuel is doped into the fuel of a methane/air flame, and it provides a measure of the intrinsic chemical tendency of the fuels to form soot in a generic combustion environment. The test fuels were real gasolines containing enhanced concentrations of alkanes, aromatics, cycloalkanes, olefins, and ethanol. These compositional differences caused the experimentally measured sooting tendencies of the fuels to vary by 240%. The surrogates were 3 mixtures defined by Szybist et al. (2017) and 3 alternative formulations modified for greater experimental convenience. The sooting tendencies measured for the surrogate mixtures agreed with the real fuels to within 15%, and varied with composition in the same order. The sooting tendencies of the surrogates could be predicted to within experimental error with an empirical quantitative structure-property relationship and a linear mixing model. The experimental flames were computationally simulated with a 743-species mechanism, and sooting tendencies derived from the results agreed with the measured values to within 11%. Altogether, these results show that the sooting behavior of gasoline can vary considerably within the range of acceptable compositions, and that these variations can be accurately predicted with empirical models and computational simulations.

09 BIOMASS FUELS↗
DOE OSTI2023

Cradle-to-grave mercury emissions of light-duty gasoline and electric vehicles in China

China is actively promoting vehicle electrification, which is deemed to help achieve its ambitious carbon neutrality goal by 2060. Here we show that vehicle electrification in China leads to an increase in automotive emissions of mercury, a persistent, global hazardous pollutant regulated in the United Nations’ Minamata Convention. We found that with current technologies, life-cycle mercury emissions of battery electric vehicles of 300 miles of all-electric range are 92% higher than conventional gasoline internal combustion engine vehicles, primarily due to the high mercury emissions from coal-based electricity generation. Notably different from greenhouse gases, mercury emissions are mainly embedded in vehicular material production and vehicle manufacturing, accounting for 50–60% for electric vehicles and ~90% for gasoline vehicles of their life-cycle mercury emissions. Even with a deeply decarbonized power grid, mercury footprints of electric vehicles would still be higher than those of gasoline vehicles, implying a potential increase in automotive mercury emissions in any countries that promote vehicle electrification. Measures including decarbonizing electric grid, implementing mercury-specific emission control through vehicle supply chain, and increasing metal recycling in electric vehicle batteries will help mitigate the unintended mercury emission increase caused by vehicle electrification.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2015

Computational Fluid Dynamics Simulation of Gasoline Compression Ignition

Gasoline compression ignition (GCI) is a low temperature combustion (LTC) concept that has been gaining increasing interest over the recent years owing to its potential to achieve diesel-like thermal efficiencies with significantly reduced engine-out nitrogen oxides (NOx) and soot emissions compared to diesel engines. In this work, closed-cycle computational fluid dynamics (CFD) simulations are performed of this combustion mode using a sector mesh in an effort to understand effects of model settings on simulation results. One goal of this work is to provide recommendations for grid resolution, combustion model, chemical kinetic mechanism, and turbulence model to accurately capture experimental combustion characteristics. Grid resolutions ranging from 0.7 mm to 0.1 mm minimum cell sizes were evaluated in conjunction with both Reynolds averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) based turbulence models. Solution of chemical kinetics using the multi-zone approach is evaluated against the detailed approach of solving chemistry in every cell. The relatively small primary reference fuel (PRF) mechanism (48 species) used in this study is also evaluated against a larger 312-species gasoline mechanism. Based on these studies the following model settings are chosen keeping in mind both accuracy and computation costs – 0.175 mm minimum cell size grid, RANS turbulence model, 48-species PRF mechanism, and multi-zone chemistry solution with bin limits of 5 K in temperature and 0.05 in equivalence ratio. With these settings, the performance of the CFD model is evaluated against experimental results corresponding to a low load start of injection (SOI) timing sweep. The model is then exercised to investigate the effect of SOI on combustion phasing with constant intake valve closing (IVC) conditions and fueling over a range of SOI timings to isolate the impact of SOI on charge preparation and ignition. Simulation results indicate that there is an optimum SOI timing, in this case -30?aTDC (after top dead center), which results in the most stable combustion. Advancing injection with respect to this point leads to significant fuel mass burning in the colder squish region, leading to retarded phasing and ultimately misfire for SOI timings earlier than -42?aTDC. On the other hand, retarding injection beyond this optimum timing results in reduced residence time available for gasoline ignition kinetics, and also leads to retarded phasing, with misfire at SOI timings later than -15?aTDC.

Energy conversion↗
DOE OSTI2015

Effect of Premixed Fuel Preparation for Partially Premixed Combustion with a Low Octane Gasoline on a Light-Duty Multi-Cylinder Compression Ignition Engine

Gasoline compression ignition concepts with the majority of the fuel being introduced early in the cycle are known as partially premixed combustion (PPC). Previous research on single- and multi-cylinder engines has shown that PPC has the potential for high thermal efficiency with low NOx and soot emissions. A variety of fuel injection strategies has been proposed in the literature. These injection strategies aim to create a partially stratified charge to simultaneously reduce NOx and soot emissions while maintaining some level of control over the combustion process through the fuel delivery system. The impact of the direct injection strategy to create a premixed charge of fuel and air has not previously been explored, and its impact on engine efficiency and emissions is not well understood. This paper explores the effect of sweeping the direct injected pilot timing from -91° to -324° ATDC, which is just after the exhaust valve closes for the engine used in this study. During the sweep, the pilot injection consistently contained 65% of the total fuel (based on command duration ratio), and the main injection timing was adjusted slightly to maintain combustion phasing near top dead center. A modern four cylinder, 1.9 L diesel engine with a variable geometry turbocharger, high pressure common rail injection system, wide included angle injectors, and variable swirl actuation was used in this study. The pistons were modified to an open bowl configuration suitable for highly premixed combustion modes. The stock diesel injection system was unmodified, and the gasoline fuel was doped with a lubricity additive to protect the high pressure fuel pump and the injectors. The study was conducted at a fixed speed/load condition of 2000 rpm and 4.0 bar brake mean effective pressure (BMEP). The pilot injection timing sweep was conducted at different intake manifold pressures, swirl levels, and fuel injection GTP-15-1067, Dempsey 2 pressures. The gasoline used in this study has relatively high fuel reactivity with a research octane number of 68. The results of this experimental campaign indicate that the highest brake thermal efficiency and lowest emissions are achieved simultaneously with the earliest pilot injection timings (i.e., during the intake stroke).

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2021

Simulations of Multi-Mode Combustion Regimes Realizable In a Gasoline Direct Injection Engine

Lean and dilute gasoline compression ignition (GCI) operation in spark ignition (SI) engines are an attractive strategy to attain high fuel efficiency and low NOx levels. However, this combustion mode is often limited to low-load engine conditions due to the challenges associated with autoignition controllability. In order to overcome this constrain, multi-mode (MM) operating strategies, consisting of advanced compression ignition (ACI) at low load and conventional SI at high load, have been proposed. In this three-dimensional computational fluid dynamics study, the concept of multi-mode combustion using two RON98 gasoline fuel blends (Co-Optima Alkylate and E30) in a gasoline direct injection (GDI) engine were explored. To this end, a new reduced mechanism for simulating the kinetics of E30 fuel blend is introduced in this study. To cover the varying engine load demands for multi-mode engines, primary combustion dynamics observed in ACI and SI combustion modes was characterized and validated against experimental measurements. In order to implement part-load conditions, a strategy of mode transition between SI and ACI combustion (i.e., mixed-mode combustion) was then explored numerically by creating a virtual test condition. The results obtained from the mixed-mode simulations highlight an important feature that deflagrative flame propagation regime coexists with ignition-assisted end-gas autoignition. This study also identifies a role of turbulent flow property adjacent to premixed flame front in characterizing the mixed-mode combustion. The employed hybrid combustion model was verified to perform simulations aiming at suitable range of multi-mode engine operations.

Kim, Sayop↗
DOE OSTI2023

Assessment of an E10 gasoline surrogate: Qualitative and quantitative comparisons of in-cylinder spray morphology

A minimum-component gasoline fuel surrogate that captures both chemical and physical behaviors of a full-distillate fuel is needed for high-fidelity CFD simulations. This study evaluates gasoline spray characteristics in a direct-injection spark-ignition engine under motored operation. Two fuels are compared; PACE-20, which is a 9-component surrogate formulation of RD5-87, is compared with its target fuel RD5-87, which is a full-boiling range research grade E10 gasoline. The spray morphologies of both fuels are recorded for a centrally-located direct-injection 8-hole spray subject to intake air cross-flow during the early part of the intake stroke. High-speed imaging recorded scattered light of the side and axial projections of the liquid spray. Quantitative metrics were developed and employed to facilitate comparison of spray morphologies as well as to identify the transition in spray morphology due to flash boiling. This paper builds on a previous study of RD5-87 where coolant temperature (20°C–100°C), in-cylinder pressure (40–110 kPa), engine speed (650–1950 rpm), and injection pressure (60–180 bar) were systematically changed to span operating conditions with and without flash boiling. Images of the PACE-20 morphology are selected for a sub-set of operating conditions from the previous study where distinctive morphology changes occurred. Visual inspection of the images and quantitative metrics demonstrate that the PACE-20 spray morphology is equivalent to that of the RD5-87 in most cases. The exception was for changes in the ambient-gas pressure where the flash-boiling transition occurred at ∼5 kPa higher in-cylinder pressure for PACE-20. Three empirical metrics, Merging Index, Asymmetry, and Flash Index are proposed here and they were found to be useful both as quantitative comparisons of the fuel morphologies, and for identifying the transition in spray morphology due to flash boiling.

Kim, Namho↗
DOE OSTI2016

Radio Frequency Sensing of Particulate Matter Accumulation on a Gasoline Particulate Filter

Filter Sensing Technology’s radio frequency (RF) sensor for particulate filter on-board diagnostics (OBD) was studied on a lean gasoline engine at the National Transportation Research Center (NTRC) at Oak Ridge National Laboratory (ORNL). The response of the RF sensor to particulate matter (PM) or “soot” accumulation on the gasoline particulate filter (GPF) installed in the engine exhaust was evaluated. In addition, end plugs of the GPF were purposely removed, and subsequent changes to the RF sensor measured soot loading on the GPF were characterized. Results from the study showed that the RF sensor can accurately measure soot accumulation on a GPF; furthermore, the predicted decreased soot accumulation due to plug removal was detected by the RF sensor. Overall, the studies were short and preliminary in nature; however, clearly, the RF sensor demonstrated the capability of measuring GPF soot loading at a level suitable for use in lean gasoline engine emission control OBD and control.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2017

Gasoline Combustion Fundamentals DOE FY17 Report

Advanced automotive gasoline engines that leverage a combination of reduced heat transfer, throttling, and mechanical losses; shorter combustion durations; and higher compression and mixture specific heat ratios are needed to meet aggressive DOE VTP fuel economy and pollutant emission targets. Central challenges include poor combustion stability at low-power conditions when large amounts of charge dilution are introduced and high sensitivity of conventional inductive coil ignition systems to elevated charge motion and density for boosted high-load operation. For conventional spark ignited operation, novel low-temperature plasma (LTP) or pre-chamber based ignition systems can improve dilution tolerances while maintaining good performance characteristics at elevated charge densities. Moreover, these igniters can improve the control of advanced compression ignition (ACI) strategies for gasoline at low to moderate loads. The overarching research objective of the Gasoline Combustion Fundamentals project is to investigate phenomenological aspects related to enhanced ignition. The objective is accomplished through targeted experiments performed in a single-cylinder optically accessible research engine or an in-house developed optically accessible spark calorimeter (OASC). In situ optical diagnostics and ex situ gas sampling measurements are performed to elucidate important details of ignition and combustion processes. Measurements are further used to develop and validate complementary high-fidelity ignition simulations. The primary project audience is automotive manufacturers, Tier 1 suppliers, and technology startups—close cooperation has resulted in the development and execution of project objectives that address crucial mid- to long-range research challenges.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2018

Next Generation Three-Way Catalysts for Future, Highly Efficient Gasoline Engines (Final Technical Report)

Ford Motor Company, Oak Ridge National Laboratory, and the University of Michigan completed a 3.25 year project on exhaust catalysts for gasoline vehicles that exhibit higher activity at lower temperatures down to 150°C. Ford has successfully used catalysts on cars and trucks to control emissions for over forty years. Changes in gasoline engine technology have allowed the use of “high tech” three-way catalysts (TWCs) to simultaneously control HC (hydrocarbons), CO (carbon monoxide), and NOx (nitrogen oxides) at nearly 100% efficiency. Excess fueling is used upon engine start to heat the catalyst up to its full operating temperature of greater than 350°C, lowering fuel economy and creating particulate matter. It was desirable to develop new catalysts for lower operating temperatures that may occur with future, more efficient gasoline powered vehicles, while still being durable to 150,000 mi with peak temperatures of 960°C. The work included laboratory preparation, aging, and poisoning of catalyst materials, activity tests, and chemical analyses. The objective of this project was to demonstrate progress toward the USDRIVE goal of achieving durable 90% conversion (T90) of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) at 150°C. The project partners focused on several supported metal catalyst structures to promote lower light-off temperatures, enhance metal-support interaction, and improve durability. The raw materials (oxides of aluminum, cerium, silicon, titanium, and zirconium) were not new, but were used in novel ways. Palladium (Pd) or rhodium (Rh) were supported either on layered metal oxide supports, on nanoparticles, or used in various core@shell configurations. Catalyst materials were aged hydrothermally to a simulated high mileage. The catalyst formulation with the lowest durable light-off was 0.5 wt% Rh supported on alumina with an overlayer of either Ti or Zr. The temperatures for 90% conversion were up to 128°C lower than those of a commercial Pd three-way catalyst that had > 3x metal loading of the new Rh catalyst. An additional material made of Pd supported on nanoparticles of ceria-zirconia (CZO) was also considered; the aged T90s were up to 40°C lower than the commercial catalyst, at similar metal loading. Further understanding of the catalyst architecture provided additional confidence to move forward with scale-up of 0.5 wt% Rh/Ti/Al2O3 to coated monolith laboratory cores for further evaluation. The team worked with Johnson Matthey to accomplish this, in addition to exploring manufacturability and potential costs. The overall benefit was estimated to be 10-15% lower NMOG and NOx tailpipe emissions on a cold start certification cycle.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Next Generation Three-Way Catalysts for Future, Highly Efficient Gasoline Engines (Final Report)

Ford Motor Company, Oak Ridge National Laboratory, and the University of Michigan completed a 3.25 year project on exhaust catalysts for gasoline vehicles that exhibit higher activity at lower temperatures down to 150°C. Ford has successfully used catalysts on cars and trucks to control emissions for over forty years. Changes in gasoline engine technology have allowed the use of “high tech” three-way catalysts (TWCs) to simultaneously control HC (hydrocarbons), CO (carbon monoxide), and NOx (nitrogen oxides) at nearly 100% efficiency. Excess fueling is used upon engine start to heat the catalyst up to its full operating temperature of greater than 350°C, lowering fuel economy and creating particulate matter. It was desirable to develop new catalysts for lower operating temperatures that may occur with future, more efficient gasoline powered vehicles, while still being durable to 150,000 mi with peak temperatures of 960°C. The work included laboratory preparation, aging, and poisoning of catalyst materials, activity tests, and chemical analyses. The objective of this project was to demonstrate progress toward the USDRIVE goal of achieving durable 90% conversion (T90) of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) at 150°C. The project partners focused on several supported metal catalyst structures to promote lower light-off temperatures, enhance metal-support interaction, and improve durability. The raw materials (oxides of aluminum, cerium, silicon, titanium, and zirconium) were not new, but were used in novel ways. Palladium (Pd) or rhodium (Rh) were supported either on layered metal oxide supports, on nanoparticles, or used in various core@shell configurations. Catalyst materials were aged hydrothermally to a simulated high mileage. The catalyst formulation with the lowest durable light-off was 0.5 wt% Rh supported on alumina with an overlayer of either Ti or Zr. The temperatures for 90% conversion were up to 128°C lower than those of a commercial Pd three-way catalyst that had > 3x metal loading of the new Rh catalyst. An additional material made of Pd supported on nanoparticles of ceria-zirconia (CZO) was also considered; the aged T90s were up to 40°C lower than the commercial catalyst, at similar metal loading. Further understanding of the catalyst architecture provided additional confidence to move forward with scale-up of 0.5 wt% Rh/Ti/Al 2 O 3 to coated monolith laboratory cores for further evaluation. The team worked with Johnson Matthey to accomplish this, in addition to exploring manufacturability and potential costs. The overall benefit was estimated to be 10-15% lower NMOG and NOx tailpipe emissions on a cold start certification cycle.

02 PETROLEUM↗