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Biodiesel (i.e., mono-alkyl esters of long chain fatty acids derived from vegetable oils and animal fats) is a renewable diesel fuel providing life-cycle greenhouse gas emission reductions relative to petroleum-derived diesel. With the expectation that there would be widespread use of biodiesel as a substitute for ultra-low sulfur diesel (ULSD), there have been many studies looking into the effects of biodiesel on engine and aftertreatment, particularly its compatibility to the current aftertreatment technologies. The objective of this study was to generate experimental data to measure the effectiveness of a current technology diesel oxidation catalysts (DOC) to oxidize soy-based biodiesel at various blend levels with ULSD. Biodiesel blends from 0 to 100% were evaluated on an engine using a conventional DOC.

The quality of neat biodiesel (B100) is critical for ensuring biodiesel blends used in diesel-powered vehicles do not adversely impact engine performance. In the United States, B100 is required to meet ASTM International’s purity and fuel property requirements in D6751, “Standard Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate Fuels.” Here we review the development of this standard for the different grades of B100. The BQ-9000 program, which currently covers over 90% of U.S. and Canadian production volumes, is also described. Engine and original equipment manufacturers have expressed a desire for credible, third-party data on values of various ASTM B100 properties in the commercial market to inform their efforts to address future emissions and durability requirements.

The project objective was to generate experimental data to evaluate the impact of metals doped B20 on DPF ash loading and performance compared to that of conventional petrodiesel. Accelerated ash loading was conducted on two DPFs – one exposed to regular diesel fuel and the other to B20 containing metal dopants equivalent to 4 ppm B100 total metals (currently total metals are limited to 10 ppm in ASTM D6751, the standard for B100). Periodic performance evaluations were conducted on the DPFs at 10 g/L ash loading intervals. After the evaluations at 30 g/L, the DPF was cleaned with a commercial DPF cleaning machine and another round of DPF evaluations were conducted. A comparison of the effect of ash loading with the two fuels and DPF cleaning is presented. The metals doped B20 fuel resulted in ash that was similar to that deposited when exposed to ULSD (lube oil ash) and exhibited similar ash cleaning removal efficiency.

This project’s objective was to generate experimental data to evaluate the impact of metals doped B20 on diesel particle filter (DPF) ash loading and performance compared to that of conventional petrodiesel. The effect of metals doped B20 vs. conventional diesel on a DPF was quantified in a laboratory controlled accelerated ash loading study. The ash loading was conducted on two DPFs – one using ULSD fuel and the other on B20 containing metals dopants equivalent to 4 ppm B100 total metals. Engine oil consumption and B20 metals levels were accelerated by a factor of 5, with DPFs loaded to 30 g/L of ash. Details of the ash loading experiment and on-engine DPF performance evaluations are presented in the companion paper (Part I). The DPFs were cleaned, and ash samples were taken from the cleaned material. X-ray Fluorescence (XRF), X-Ray Photoelectron Spectroscopy (XPS) and X-Ray Diffraction (XRD) were conducted on the ash samples.

In order to decarbonize and lower the overall emissions of the transport sector, immediate and cost-effective powertrain solutions are needed. Natural gas offers the advantage of a direct reduction of carbon dioxide (CO2) emissions due to its better Carbon to Hydrogen ratio (C/H) compared to common fossil fuels, e.g. gasoline or diesel. Moreover, an optimized engine design suiting the advantages of natural gas in knock resistance and lean mixtures keeping in mind the challenges of power density, efficiency and cold start manoeuvres. In the public funded project MethMag (Methane lean combustion engine) a gasoline fired three-cylinder-engine is redesigned based on this change of requirements and benchmarked against the previous gasoline engine.

Conventional diesel combustion, also known as Mixing-Controlled Compression Ignition (MCCI), is expected to be the primary power source for medium- and heavy-duty vehicles for decades to come. Displacing petroleum-based ultra-low-sulfur diesel (ULSD) as much as possible with low-net-carbon biofuels will become necessary to help mitigate effects on climate change. Neat biofuels may have difficulty meeting current diesel fuel standards but blends of 30% biofuel in ULSD show potential as ‘drop-in’ fuels. These blends must not make significant changes to the combustion phasing of the MCCI process if they are to be used interchangeably with neat ULSD. An important aspect of MCCI phasing is the ignition delay (ID), i.e. the time between the start of fuel injection and the initial premixed autoignition that initiates the MCCI process.

Conventional diesel engines will continue to hold a vital role in the heavy- and medium-duty markets for the transportation of goods along with many other uses. The ability to offset traditional diesel fuels with low-net-carbon biofuels could have a significant impact on reducing the carbon footprint of these vehicles. A prior study screened several hundred candidate biofuel blendstocks based on required diesel blendstock properties and identified 12 as the most promising. Eight representative biofuel blendstocks were blended at a 30% volumetric concentration with EPA certification ultra-low-sulfur diesel (ULSD) and were investigated for emissions and fuel efficiency performance. This study used a single cylinder engine (based on the Ford 6.7L engine) using Conventional Diesel Combustion (CDC), also known as Mixing Control Compression Ignition (MCCI). The density, cetane number, distillation curve and sooting tendency (using the yield sooting index method) of the fuels were measured.

DME has been considered an alternative fuel to diesel fuel with promising benefits because of its high reactivity and volatility. Research shows that an engine fueled with DME will produce zero smoke emissions. However, the storage and the handling of the fuel are underlying difficulties owing to its high vapour pressure (530 kPa @ 20 °C). In lieu, OME1 fuel, a derivate of DME, offers advantages exhibited with DME fuel, all the while being a liquid fuel for engine application. In this work, engine tests are performed to realize the combustion behaviour of DME and OME1 fuel on a single-cylinder research engine with a compression ratio of 9.2:1. The dilution ratio of the mixture is progressively increased in two manners, allowing more air in the cylinder and applying exhaust gas recirculation (EGR). The high reactivity of DME suits the capability to be used in compression ignition combustion whereas OME1 must be supplied with a supplemental spark to initiate the combustion.

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.

Mixing controlled compression ignition, i.e., diesel engines are efficient and are likely to continue to be the primary means for movement of goods for many years. Low-net-carbon biofuels have the potential to significantly reduce the carbon footprint of diesel combustion and could have advantageous properties for combustion, such as high cetane number and reduced engine-out particle and NOx emissions. We developed a list of over 400 potential biomass-derived diesel blendstocks and populated a database with the properties and characteristics of these materials. Fuel properties were determined by measurement, model prediction, or literature review. Screening criteria were developed to determine if a blendstock met the basic requirements for handling in the diesel distribution system and use as a blend with conventional diesel. Criteria included cetane number ≥40, flashpoint ≥52°C, and boiling point or T90 ≤338°C.

Evaporative cooling of the fuel-air charge by fuel evaporation is an important feature of direct-injection spark-ignition engines that improves fuel knock resistance and reduces pumping losses at intermediate load, but in some cases, may increase fine particle emissions. We have reported on experimental approaches for measuring both total heat of vaporization and examination of the evaporative heat effect as a function of fraction evaporated for gasolines and ethanol blends. In this paper, we extend this work to include other low-molecular-weight alcohols and present results on species evolution during fuel evaporation by coupling a mass spectrometer to our differential scanning calorimetry/thermogravimetric analysis instrument. The alcohols examined were methanol, ethanol, 1-propanol, isopropanol, 2-butanol, and isobutanol at 10 volume percent, 20 volume percent, and 30 volume percent.

Combined direct and port fuel injection (i.e., dual injection) in spark ignition engines is of increasing interest due to the advantages for fuel flexibility and the individual merits of each system for improving engine performance and reducing engine-out emissions. Greater understanding of the impact of dual injection will enable deriving the maximum benefit from the two injection systems. This study investigates the effects of dual injection on combustion, especially knock propensity and tolerance to exhaust gas recirculation (EGR) dilution at different levels of EGR. A baseline for comparison with dual injection results was made using direct injection fueling only. A splash blended E20 fuel was used for the direct injection only tests. For the dual injection tests, gasoline, representing 80% by volume of the total fuel, was injected using the direct injector, and ethanol, representing 20% by volume of the total fuel, was injected using the port fuel injector.

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.

Future LEV-III tailpipe (TP) emission regulations pose an enormous challenge forcing the fleet average of light-duty vehicles produced in the 2025 model year to perform at the super ultralow emission vehicle (SULEV-30) certification levels (versus less than 20% produced today). To achieve SULEV-30, regulated TP emissions of non-methane organic gas (NMOG) hydrocarbons (HCs) and oxygenates plus oxides of nitrogen (NOx) must be below a combined 30 mg/mi (18.6 mg/km) standard as measured on the federal emissions certification cycle (FTP-75). However, when flex-fuel vehicles use E85 fuel instead of gasoline, NMOG emissions at cold start are nearly doubled, before the catalytic converter is active. Passive HC traps (HCTs) are a potential solution to reduce TP NMOG emissions. The conventional HCT design was modified by changing the zeolite chemistry so as to improve HC retention coupled with more efficient combustion during the desorption phase.

In the development of HC traps (HCT) for reducing vehicle cold start hydrocarbon (HC)/nitrogen oxide (NOx) emissions, zeolite-based adsorbent materials were studied as key components for the capture and release of the main gasoline-type HC/NOx species in the vehicle exhaust gas. Typical zeolite materials capture and release certain HC and NOx species at low temperatures (<200°C), which is lower than the light-off temperature of a typical three-way catalyst (TWC) (≥250°C). Therefore, a zeolite alone is not effective in enhancing cold start HC/NOx emission control. We have found that a small amount of Pd (<0.5 wt%) dispersed in the zeolite (i.e., BEA) can significantly increase the conversion efficiency of certain HC/NOx species by increasing their release temperature. Pd was also found to modify the adsorption process from pure physisorption to chemisorption and may have played a role in the transformation of the adsorbed HCs to higher molecular weight species.

Knock-limited loads for a set of surrogate gasolines all having nominal 100 research octane number (RON), approximately 11 octane sensitivity (S), and a heat of vaporization (HOV) range of 390 to 595 kJ/kg at 25°C were investigated. A single-cylinder spark-ignition engine derived from a General Motors Ecotec direct injection (DI) engine was used to perform load sweeps at a fixed intake air temperature (IAT) of 50 °C, as well as knock-limited load measurements across a range of IATs up to 90 °C. Both DI and pre-vaporized fuel (supplied by a fuel injector mounted far upstream of the intake valves and heated intake runner walls) experiments were performed to separate the chemical and thermal effects of the fuels’ knock resistance. The DI load sweeps at 50°C intake air temperature showed no effect of HOV on the knock-limited performance. The data suggest that HOV acts as a thermal contributor to S under the conditions studied.

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.

Today’s electric vehicle (EV) owners charge their vehicles mostly at home and seldom use public direct current fast charger (DCFCs), reducing the need for a large deployment of DCFCs for private EV owners. However, due to the emerging interest among transportation network companies to operate EVs in their fleet, there is great potential for DCFCs to be highly utilized and become economically feasible in the future. This paper describes a heuristic algorithm to emulate operation of EVs within a hypothetical transportation network company fleet using a large global positioning system data set from Columbus, Ohio. DCFC requirements supporting operation of EVs are estimated using the Electric Vehicle Infrastructure Projection tool. Operation and installation costs were estimated using real-world data to assess the economic feasibility of the recommended fast charging stations.

Natural gas (NG) is attractive for heavy-duty (HD) engines for reasons of cost stability, emissions, and fuel security. NG cannot be reliably compression-ignited, but conventional gasoline ignition systems are not optimized for NG and are challenged to ignite mixtures that are lean or diluted with exhaust-gas recirculation (EGR). NG ignition is particularly challenging in large-bore engines, where completing combustion in the available time is more difficult. Using two high-speed infrared (IR) cameras with borescopic access to one cylinder of an HD NG engine, the effect of ignition system on the early flame-kernel development and cycle-to-cycle variability (CCV) was investigated. Imaging in the IR yielded strong signals from water emission lines, which located the flame front and burned-gas regions and obviated image intensifiers. A 9.7-liter, six-cylinder engine was modified to enable exhaust-gas recirculation and to provide optical access.

Numerous studies have demonstrated the benefits of ethanol in increasing the thermal efficiency of gasoline-fueled spark ignition engines via the higher enthalpy of vaporization and higher knock resistance of ethanol compared with gasoline. This study expands on previous work by considering a split fuel injection strategy with a boosted direct injection spark ignition engine fueled with E0 (100% by volume reference grade gasoline; with research octane number = 91 and motor octane number = 83), E100 (100% by volume anhydrous ethanol), and various splash-blends of the two fuels. Experiments were performed using a production 3-cylinder Ford Ecoboost engine where two cylinders were de-activated to create a single-cylinder engine with a displacement of 0.33 L. The engine was operated over a range of loads with boosted intake manifold absolute pressure (MAP) from 1 bar to 1.5 bar.