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Alternative and renewable fuels show tremendous promise for addressing concerns of energy security, energy supply, and CO₂ emissions. However, the new fuels have the potential to produce non-regulated exhaust components that may be as detrimental or worse, than currently regulated emissions components. For the 2009 SAE Clean Snowmobile Challenge (CSC), a commercially available Fourier Transform Infrared (FTIR) spectrometer was used to sample raw exhaust from eight student teams' snowmobiles for comparative analysis with a conventional emissions bench. The levels of CO₂, CO, NO , O₂, and THC were compared for the five operating modes, which included both gasoline- and diesel-powered snowmobiles. The fuel was either an ethanol blend for spark-ignition engines or a biodiesel for compression-ignition engines. Final emissions result scores varied by less than 2% between the conventional emissions bench and the FTIR.

An operational scheme with fuel-lean and exhaust gas dilution in spark-ignited engines increases thermal efficiency and decreases NOx emission, while these operations inherently induce combustion instability and thus large cycle-to-cycle variation in engine. In order to stabilize combustion variations, the development of an advanced ignition system is becoming critical. To quantify the impact of spark-ignition discharge, ignitability tests were conducted in an optically accessible combustion vessel to characterize the flame kernel development of lean methane-air mixture with CO₂ simulating exhaust diluent. A shrouded fan was used to generate turbulence in the vicinity of J-gap spark plug and a Variable Output Ignition System (VOIS) capable of producing a varied set of spark discharge patterns was developed and used as an ignition source. The main feature of the VOIS is to vary the secondary current during glow discharge including naturally decaying and truncated with multiple strikes.

This paper studies the bi-directional power flow control between Plug-in Electric Vehicles (PEVs) and an electrical grid. A grid-tied charging system that enables both Grid-to-Vehicle (G2V) and Vehicle-to-Grid (V2G) charging/discharging is modeled using SimPowerSystems in Matlab/Simulink environment. A bi-directional AC-DC converter and a bi-directional DC-DC buck-boost converter are integrated to charge and discharge PEV batteries. For AC-DC converter control, Predictive Current Control (PCC) strategy is employed to enable grid current to reach a reference current after one modulation period. In addition, Phase Lock Loop (PLL) and a band-stop filter are designed to lock the grid voltage phase and reduce harmonics. Bi-directional power flow is realized by controlling the mode of the DC-DC converter. Simulation tests are conducted to evaluate the performance of this bi-directional charging system.

Interest in natural gas as an alternative fuel source to petroleum fuels for light-duty vehicle applications has increased due to its domestic availability and stable price compared to gasoline. With its higher hydrogen-to-carbon ratio, natural gas has the potential to reduce engine out carbon dioxide emissions, which has shown to be a strong greenhouse gas contributor. For part-load conditions, the lower flame speeds of natural gas can lead to an increased duration in the inflammation process with traditional port-injection. Direct-injection of natural gas can increase in-cylinder turbulence and has the potential to reduce problems typically associated with port-injection of natural gas, such as lower flame speeds and poor dilution tolerance. A study was designed and executed to investigate the effects of direct-injection of natural gas at part-load conditions.

The combustion and exhaust emission characteristics of a DME fueled HCCI engine were investigated. Different fuel injection strategies were tested under various injection quantities and timings with exhaust gas recirculation (EGR). The combustion phase in HCCI was changed by an in-cylinder direct injection and EGR, due to changes in the in-cylinder temperature and mixture homogeneity. The gross indicated mean effective pressure (IMEPgross) increased and the hydrocarbon (HC) and carbon monoxide (CO) emissions decreased as the equivalence ratio was augmented. The IMEPgross with direct injection was greater than with the port injection due to retarded ignition timing resulting from latent heat of direct injected DME fuel. It was because that most of burn duration was completed before top dead center owing to higher ignitability for DME with high cetane number. However, HC and CO emissions were similar for both injection locations.

The vehicle driving cycles affect the performance of a hybrid vehicle control strategy, as a result, the overall performance of the vehicle, such as fuel consumption and emission. By identifying the driving cycles of a vehicle, the control system is able to dynamically change the control strategy (or parameters) to the best one to adapt to the changes of vehicle driving patterns. This paper studies the supervised driving cycle recognition using pattern recognition approach. With pattern recognition method, a driving cycle is represented by feature vectors that are formed by a set of parameters to which the driving cycle is sensitive. The on-line driving pattern recognition is achieved by calculating the feature vectors and classifying these feature vectors to one of the driving patterns in the reference database. To establish reference driving cycle database, the representative feature vectors for four federal driving cycles are generated using feature extraction method.

Diesel combustion and emissions formation is spray and mixing controlled and understanding spray parameters is key to determining the impact of fuel injector operation and nozzle design on combustion and emissions. In this study, both spray visualization and computational fluid dynamics (CFD) modeling were undertaken to investigate key mechanisms for liquid length fluctuations. For the experimental portion of this study a common rail piezoelectric injector was tested in an optically accessible constant volume combustion vessel. Liquid penetration of the spray was determined via processing of images acquired from Mie back scattering under vaporizing conditions by injecting into a charge gas at elevated temperature with a 0% oxygen environment. Tests were undertaken at a gas density of 34.8 kg/m₃, 2000 bar injection pressure, and at ambient temperatures of 900, 1100, and 1300 K.

The vast stores of biomass available worldwide have the potential to displace significant amounts of petroleum fuels. Fast pyrolysis of biomass is one of several possible paths by which we can convert biomass to higher value products. Pyrolysis oil (PO) derived from wood has been regarded as an alternative fuel to be used in diesel engines. However, the use of PO in a diesel engine requires engine modifications due to the low energy density, high acidity, high viscosity, and low cetane number of PO. Therefore, PO should be blended or emulsified with other fuels that have a high cetane number or used through pilot injection. PO has poor miscibility with light petroleum fuel oils; the most suitable candidate fuels for direct fuel mixing are alcohol fuels. Early mixing with alcohol fuels has the added benefit of significantly improving the storage and handling properties of the PO.

Characteristics of syngas combustion at various reforming ratios were studied numerically. The syngas was formed by the partial oxidation of methane to mainly hydrogen and carbon monoxide and cooled to ambient temperature. Stiochiometric and lean premixed flames of the mixtures of methane and the syngas were compared at the atmospheric temperature and pressure conditions. The adiabatic flame temperature decreased with the reforming ratio. The laminar burning velocity, however, increased with the reforming ratio. For stretched flames in a counterflow, the high temperature region was broadened with the reforming ratio. The maximum flame temperature decreased with the reforming ratio for the stoichiometric case, but increased for the lean case except for the region of very low stretch rate. The extinction stretch rate increased with the reforming ratio, implying that the syngas assisted flame is more resistance to turbulence level.

Since it is well known that the flow and spray characteristics are critical factors on the performance and emission in a direct-injection diesel engine, this study aims to investigate the interaction between flow and spray characteristics. At first, in-cylinder flow distributions in swirl/tumble adapter for 4-valve cylinder head of DI diesel engine were investigated under steady conditions with different SCV angles mounted on the cylinder head by using 2-D LDV. It was found that swirl flow is more dominant than tumble on spray interaction in the engine. For the analysis, the in-cylinder flow was quantified in terms of non-dimensional rig swirl/tumble, mean flow coefficient, swirl ratio/tumble ratio. It was confirmed that the swirl ratio is controlled between 2.3 and 3.8 by changing SCV angles. Spray characteristics of the intermittent injection also were investigated by using PDA system to measure droplet size and velocity.

Various alternative diesel fuels such as gas to liquid (GTL) fuels, blends of diesel and biodiesel (D + BD20), and blends of GTL and biodiesel (G + BD20) were tested in a 2.0 L four-cylinder turbocharged diesel engine. A noticeable reduction in exhaust emissions as compared to diesel fuel, except for NOx emissions, was observed by blending biodiesel with diesel and GTL fuel under selected part load conditions. There was a maximum reduction of 33% for THC emissions and 27% for CO emissions for G + BD20 fuel as compared to diesel fuel. For PM size distributions, a noticeable decrease in the PM number concentration for all particle sizes less than 300 nm was observed with the blending of biodiesel. In contrast, there was a slight increase in the number concentration of PM with diameters of less than 50 nm for the cases of EGR. In the case of particulate matter (PM) mass concentration, there were reductions of 31~59% for D + BD20 fuel and 57~71% for G + BD20 fuel.

Combustion and emission characteristics of LPG(Liquefied Petroleum Gas) and gasoline fuels were compared in a single cylinder engine with direct fuel injection. While fuel injection pressure and IMEP(indicated mean effective pressure) were varied with 60, 90, 120 bar and 2 to 10 bar, another parameters for the engine operation as engine speed, air excess, and fuel injection timing were fixed at 1500 rpm, 1.0, and BTDC 300 CA respectively. Experimental results showed that MBT timing for LPG was less sensitive to IMEP, and high injection pressure made combustion stability worse at IMEP=2 bar. Through heat release analysis LPG showed shorter 10 and 90% MBD(mass burn duration) than gasoline due to fast flame speed and for both fuels injection pressure hardly affected burn duration. It was also found that thermal efficiency of LPG had a little higher than that of gasoline. Hydrocarbon emissions of gasoline rose to a level of three-fold than those of LPG.

Recent increases in emissions regulations within the snowmobile industry have led to significant advancements in fuel, exhaust, and control systems on snowmobiles. However, particulate matter is currently an unregulated exhaust component of snowmobile engines. The measurement of dry soot as well as particulate matter from snowmobiles is the focus of this paper. Two industry-representative snowmobiles were chosen for this research which included a 2006 Yamaha Nytro carbureted four-stroke and a 2009 Ski-Doo MX-Z direct-injected two-stroke. Measurements for each snowmobile included gaseous emissions (CO₂, CO, NOx, O₂, and THC), particulate matter collected on quartz filters, and dry soot measured using an AVL Micro Soot Sensor. Each snowmobile was tested over the industry-standard five-mode emissions certification test cycle to determine the emissions, dry soot, and particulate matter levels from idle to wide open throttle (full-load).

Reactivity Controlled Compression Ignition (RCCI) is a promising dual-fuel Low Temperature Combustion (LTC) mode with significant potential for reducing NOx and particulate emissions while improving or maintaining thermal efficiency compared to Conventional Diesel Combustion (CDC) engines. The large reactivity difference between diesel and Natural Gas (NG) fuels provides a strong control variable for phasing and shaping combustion heat release. In this work, the Brake Thermal Efficiencies (BTE), emissions and combustion characteristics of a light duty 1.9L, four-cylinder diesel engine operating in single fuel diesel mode and in Diesel-NG RCCI mode are investigated and compared. The engine was operated at speeds of 1300 to 2500 RPM and loads of 1 to 7 bar BMEP. Operation was limited to 10 bar/deg Maximum Pressure Rise Rate (MPRR) and 6% Coefficient of Variation (COV) of IMEP.

Low Temperature Combustion (LTC) engines are promising to improve powertrain fuel economy and reduce NOx and soot emissions by improving the in-cylinder combustion process. However, the narrow operating range of LTC engines limits the use of these engines in conventional powertrains. Extended range electric vehicles (EREVs), by decoupling the engine from the drivetrain, allows the engine to operate in a limited operating range; thus, EREVs offer an ideal platform for realizing the advantages of LTC engines. In this study, the global optimum fuel economy improvement of an experimentally developed 2-liter multi-mode LTC engine in a series EREV is investigated. The engine operation modes include Homogeneous-Charge Compression Ignition (HCCI), Reactivity Controlled Compression Ignition (RCCI), and conventional Spark Ignition (SI).

The medium and heavy duty vehicle industry has fostered an increase in emissions research with the aim of reducing NOx while maintaining power output and thermal efficiency. This research describes a proof-of-concept numerical study conducted on a Caterpillar single-cylinder research engine. The target of the study is to reduce NOx by taking a unique approach to combustion air handling and utilizing enriched nitrogen and oxygen gas streams provided by Air Separation Membranes. A large set of test cases were initially carried out for closed-cycle situations to determine an appropriate set of operating conditions that are conducive for NOx reduction and gas diffusion properties. Several parameters - experimental and numerical, were considered. Experimental aspects, such as engine RPM, fuel injection pressure, start of injection, spray inclusion angle, and valve timings were considered for the parametric study.

This paper presents results on how the Equivalent Consumption Minimization Strategy (ECMS) penalty factor effects Lithium ion battery aging. The vehicle studied is the Honda Civic Hybrid. The battery used is A123 Systems’. Vehicle simulation using multiple combinations of highway and city drive cycles. For each combination of drive cycles, six ECMS penalty factor values are used. Battery aging is evaluated using a semi-empirical model combined with accumulated Ah-throughput method which uses, as an input, the battery state of charge trajectory from the vehicle simulations. The tradeoff between fuel cost and battery aging cost is explicitly displayed. In addition, the results provide insight into how driving behavior affects battery aging. The paper concludes with a discussion of the optimal balance between fuel cost and battery aging.

CNG/diesel dual-fuel engine is using CNG as a main fuel, and injects diesel only a little as an ignition priming. In this study, remodeling an existing diesel engine into dual-fuel engine that can inject diesel with high pressure by CRDI (Common Rail Direct Injection), and injecting CNG at intake port for premixing. The results show that CNG/diesel dual-fuel engine satisfied coordinate torque and power with conventional diesel engine. And CNG alternation rate is over 89% in all operating ranges of CNG/diesel dual-fuel engine. PM emission is lower 94% than diesel engine, but NOx emission is higher than diesel engine. The output of dual fuel mode is 95% by the diesel mode. At this time, amount of CO₂ and PM are decreased while CO, NOx, and THC are increased. In NEDC mode, exhaust gases except NOx are decreased.

A low temperature combustion (LTC) diesel engine has been under investigation for reduction of NOx and soot with acceptable compromise in the efficiency through modification of the combustion process. In this paper computational simulation is performed as a preliminary step for development of an LTC diesel engine for off-highway construction vehicles. Validation is performed for major physical models against measurements in LTC conditions. The conditional moment closure (CMC) is employed to address coupling between chemistry and turbulence in KIVA-CMC. The Kelvin-Helmholtz/Rayleigh-Taylor (KH-RT) model is employed for spray breakup and a skeletal n-heptane mechanism for both low and high temperature chemistry. Parametric evaluation is performed for design and operating conditions including EGR rate and injection timing. Results are obtained for efficiency, IMEP, CO, NOx and PM emissions at intake boost pressures of 1, 2 and 3 bar.

The catalyzed particulate filter (CPF), used in conjunction with a diesel oxidation catalyst (DOC) is an important aftertreatment device used to meet Environmental Protection Agency (EPA) heavy-duty diesel emission standards for particulate matter (PM). Numerical modeling of these exhaust after-treatment devices decreases the time and cost of development involved. Modeling CPF active regeneration gives insight into the PM oxidation kinetics, which helps in reducing the regeneration fuel penalty. As seen from experimental data, active regeneration of the CPF results in a significant temperature increase into the CPF (up to 8°C/sec) which affects the oxidation rate of particulate matter (PM). PM oxidation during active regeneration was determined to be a function of filter PM loading, inlet temperature and inlet hydrocarbon concentration.