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The effects of combining premixed, low temperature combustion (LTC) with biodiesel are relatively unknown to this point. This mode allows simultaneously low soot and NOx emissions by using high rates of EGR and increasing ignition delay. This paper compares engine performance and emissions of neat, soy-based methyl ester biodiesel (B100), B20, B50, pure ultra low sulfur diesel (ULSD) and a Swedish, low aromatic diesel in a multi-cylinder diesel engine operating in a late-injection premixed LTC mode. Using heat release analysis, the progression of LTC combustion was explored by comparing fuel mass fraction burned. B100 had a comparatively long ignition delay compared with Swedish diesel when measured by start of ignition (SOI) to 10% fuel mass fraction burned (CA10). Differences were not as apparent when measured by SOI to start of combustion (SOC) even though their cetane numbers are comparable.

Stringent fuel economy and emissions regulations have driven development of new mixture preparation technologies and increased spark-ignition engine complexity. Additional degrees of freedom, brought about by devices such as cam phasers and charge motion control valves, enable greater range and flexibility in engine control. This permits significant gains in fuel efficiency and emission control, but creates challenges related to proper engine control and calibration techniques. Accurate experimental characterization of high degree of freedom engines is essential for addressing the controls challenge. In particular, this paper focuses on the evaluation of three experimental residual gas fraction measurement techniques for use in a spark ignition engine equipped with dual-independent variable camshaft phasing (VVT).

Compact heat exchangers are commonly used in diesel engines to reduce the temperature of recirculated exhaust gases, resulting in decreased NOx emissions. These exhaust gas recirculation (EGR) coolers experience fouling through deposition of particulate matter (PM) and hydrocarbons (HCs) that reduces the effectiveness of the cooler. Surrogate tubes have been used to investigate the impacts of gas flow rate and coolant temperature on the deposition of PM and HCs. The results indicate that mass deposition is lowest at high flow rates and high coolant temperatures. An oxidation catalyst was investigated and proved to effectively reduce deposition of HCs, but did not reduce overall mass deposition to near-zero levels. Speciation of the deposit HCs showed that a range of HCs from C15 - C25 were deposited and retained in the surrogate tubes.

The buildup of deposits in EGR coolers causes significant degradation in heat transfer performance, often on the order of 20-30%. Deposits also increase pressure drop across coolers and thus may degrade engine efficiency under some operating conditions. It is unlikely that EGR cooler deposits can be prevented from forming when soot and HC are present. The presence of cooled surfaces will cause thermophoretic soot deposition and condensation of HC and acids. While this can be affected by engine calibration, it probably cannot be eliminated as long as cooled EGR is required for emission control. It is generally felt that “dry fluffy” soot is less likely to cause major fouling than “heavy wet” soot. An oxidation catalyst in the EGR line can remove HC and has been shown to reduce fouling in some applications. The combination of an oxidation catalyst and a wall-flow filter largely eliminates fouling. Various EGR cooler designs affect details of deposit formation.

Internal combustion (IC) engines fueled by hydrogen are among the most efficient means of converting chemical energy to mechanical work. The exhaust has near-zero carbon-based emissions, and the engines can be operated in a manner in which pollutants are minimal. In addition, in automotive applications, hydrogen engines have the potential for efficiencies higher than fuel cells.[1] In addition, hydrogen engines are likely to have a small increase in engine costs compared to conventionally fueled engines. However, there are challenges to using hydrogen in IC engines. In particular, efficient combustion of hydrogen in engines produces nitrogen oxides (NOx) that generally cannot be treated with conventional three-way catalysts. This work presents the results of experiments which consider changes in direct injection hydrogen engine design to improve engine performance, consisting primarily of engine efficiency and NOx emissions.

A single-cylinder Direct Injection Spark Ignition (DISI) engine with optical access was used to investigate the effects of ethanol/gasoline blends on in-cylinder formation of particulate matter (PM) and fuel spray characteristics. Indolene was used as a baseline fuel and two blends of 50% and 85% ethanol (by volume, balance indolene) were investigated. Time resolved thermal radiation (incandescence/natural luminosity) of soot particles and fuel spray characteristics were recorded using a high speed camera. The images were analyzed to quantify soot formation in units of relative image intensity as a function of important engine operating conditions, including ethanol concentration in the fuel, fuel injection timing (250, 300 and 320° bTDC), and coolant temperature (25°C and 90°C). Spatially-integrated incandescence was used as a metric to quantify the level of in-cylinder PM formed at the different operating conditions.

Super-knock has been a significant obstacle for the development of highly turbocharged (downsized) gasoline engines with spark ignition, due to the catastrophic damage super-knock can cause to the engine. According to previous research by the authors, one combustion process leading to super-knock may be described as hot-spot induced pre-ignition followed by deflagration which can induce detonation from another hot spot followed by high pressure oscillation. The sources of the hot spots which lead to pre-ignition (including oil films, deposits, gas-dynamics, etc.) may occur sporadically, which leads to super-knock occurring randomly at practical engine operating conditions. In this study, a spark plasma was used to induce preignition and the correlation between super-knock combustion and the thermodynamic state of the reactant mixture was investigated in a four-cylinder production gasoline engine.

Seat belt anchorage locations have a strong effect on occupant protection. Federal Motor Vehicle Safety Standard (FMVSS) 210 specifies requirements for the layout of the anchorages relative to the seating reference point and seat back angle established by the SAE J826 H-point manikin. Sled testing and computational simulation has established that belt anchorage locations have a strong effect on occupant kinematics, particularly for child occupants using the belt as their primary restraint. As part of a larger study of vehicle geometry, the locations of the anchorage points in the second-row, outboard seating positions of 83 passenger cars and light trucks with a median model year of 2005 were measured. The lower anchorage locations spanned the entire range of lap belt angles permissible under FMVSS 210 and the upper anchorages (D-ring locations) were distributed widely as well.

When unexpected integrated lubricant-related problems occur, for example, high-speed operating conditions, lubricants can be degraded and even fail to reach certain automatic transmission parts. Dryout of oil films means a serious lack of lubrication, which may damage the power transmission line and key parts. Dryout of ATF is analogous to that in forced convective boiling and condensation. It thus requires special efforts to determine the mechanics that induce such fluid transport phenomena. This paper presents an experimental investigation of lubricant activities in the main shaft. Dimensional analysis is applied, and flow maps of the air-oil flow and dryout regimes are constructed. Correlations closely agree with the data and reveal the possibility of dryout. Heat transfer effect is briefly discussed.

Meeting diesel engine emission standards for heavy-duty vehicles can be achieved by simultaneous injection of fuel and water. An injection system for instantaneous mixing of fuel and water in the combustion chamber has been developed by injecting water in a mixing passage located in the periphery of the fuel spray. The fuel spray is then entrained by water and hot air before it burns. The experimental work was carried out on a Rapid Compression Machine and on a Komatsu direct-injection heavy-duty diesel engine with a high pressure common rail fuel injection system. It was also supported by Computational Fluid Dynamics simulations of the injection and combustion processes in order to evaluate the effect of water vapor distribution on cylinder temperature and NOX formation. It has been concluded that when the water injection is appropriately timed, the combustion speed is slower and the cylinder temperature lower than in conventional diesel combustion.

Thermal distortions of friction disks caused by frictional heating modify pressure distribution on friction surfaces. Pressure distribution, in turn, determines distribution of generated frictional heat. These interdependencies create a complex thermoelastic system that, under some conditions, may become unstable and may lead to severe pressure concentrations with very high local temperature and stress. The phenomenon is responsible for many common thermal failure modes of friction elements and is known as frictionally excited thermoelastic instability (TEI). In the paper, one of the cases of TEI is investigated theoretically and experimentally. The study involves a two-disk structure with one fiction disk and one matching steel disk that have one friction interface. An unsteady heat conduction problem and an elastic contact problem are modeled as axisymmetric ones and are solved using the finite element method.

A series of inflator tank tests was carried out to determine the amount of transient heat losses to the tank wall during these tests. The time history data of tank wall temperature, and tank interior gas temperature and pressure, were measured. The tank wall temperature data were analyzed using an inverse heat conduction method to generate the transient heat loss fluxes from the tank gas to the tank wall. The validity of the results are discussed along with the physical reasoning and experimental observations. This is the first part of an effort in a research project to develop a comprehensive heat transfer model to predict the transient heat losses to the tank wall during the inflator tank test.

Multi-zone CFD simulations with detailed kinetics were used to model iso-octane HCCI experiments performed on a single-cylinder research engine. The modeling goals were to validate the method (multi-zone combustion modeling) and the reaction mechanism (LLNL 857 species iso-octane) by comparing model results to detailed exhaust speciation data, which was obtained with gas chromatography. The model is compared to experiments run at 1200 RPM and 1.35 bar boost pressure over an equivalence ratio range from 0.08 to 0.28. Fuel was introduced far upstream to ensure fuel and air homogeneity prior to entering the 13.8:1 compression ratio, shallow-bowl combustion chamber of this 4-stroke engine. The CFD grid incorporated a very detailed representation of the crevices, including the top-land ring crevice and head-gasket crevice. The ring crevice is resolved all the way into the ring pocket volume. The detailed grid was required to capture regions where emission species are formed and retained.

Utilizing simulation technology is important for designing a structure with increased survivability to a load from an explosion. The pressure wave from the blast and the fragments hitting the structure must be simulated in such an analysis. Commercial software can be utilized through the development of appropriate interfaces for performing such computations. In this paper an approach is presented for combining commercially available Eulerian and Lagrangian solvers for performing blast event simulations. A capability has been developed for automatically creating the Eulerian finite element given the finite element model for the structure. The effect of moisture in the soil properties is considered during the generation of the soil - explosive - air model used by the Eulerian solver. Tracers are defined in the Eulerian model for all structural finite elements which are on the outer part of the structure and are subjected to the load from the blast.

Federal standards that mandate improved fuel economy have resulted in the increased use of lightweight materials in automotive applications. However, the environmental burdens associated with a product extend well beyond the use phase. Life cycle assessment is the science of determining the environmental burdens associated with the entire life cycle of a given product from cradle-to-grave. This report documents the environmental burdens associated with every phase of the life cycle of two fuel tanks utilized in full-sized 1996 GM vans. These vans are manufactured in two configurations, one which utilizes a steel fuel tank, and the other a multi-layered plastic fuel tank consisting primarily of high density polyethylene (HDPE). This study was a collaborative effort between GM and the University of Michigan's National Pollution Prevention Center, which received funding from EPA's National Risk Management Research Laboratory.

A particle swarm optimization (PSO) solver is developed based on theoretical information available from the literature. In the main new effort presented in this paper, an approach is developed for integrating the PSO algorithm as a driver at both the top and the discipline levels of a multidisciplinary design optimization (MDO) framework which is based on the Target Cascading (TC) method. The integrated MDO/PSO algorithm is employed for analyzing a multidiscipline optimization statement reflecting the conceptual ship design problem from the literature. The results, the strengths, and the weaknesses of the integrated MDO/PSO algorithm are discussed as related to conceptual ship design.

A method is presented here that detects aircraft tail surface icing that might normally be unobserved by the flight crew. Such icing can be detected through the action of highly computationally efficient signal processing of existing sensor signals using a so-called failure detection filter (FDF). The FDF creates a unique output signature permitting relatively early detection of tail surface icing. The FDF incorporates a stable state estimator from which the icing signature is created. This estimator is robust to analytical modeling errors or uncertainties, and to process noise (e.g. turbulence). Excellent performance of the method is demonstrated via simulation.

Premixed diesel combustion is intended to supplant conventional combustion in the light to mid load range. This paper demonstrates the operating load limits, limiting criteria, and load-based emissions behavior of a direct-injection, diesel-fueled, premixed combustion mode across a range of test fuels. Testing was conducted on a modern single-cylinder engine fueled with a range of ultra-low sulfur fuels with cetane number ranging from 42 to 53. Operating limits were defined on the basis of emissions, noise, and combustion stability. The emissions behavior and operating limits of the tested premixed combustion mode are independent of fuel cetane number. Combustion stability, along with CO and HC emissions levels, dictate the light load limit. The high load limit is solely dictated by equivalence ratio: high PM, CO, and HC emissions result as overall equivalence ratio approaches stoichiometric.

A numerical study has been conducted to investigate possible extension of the low load limit of the HCCI operating range by charge stratification using direct injection. A wide range of SOI timings at a low load HCCI engine operating condition were numerically examined to investigate the effect of DI. A multidimensional CFD code KIVA3v with a turbulent combustion model based on a modified flamelet approach was used for the numerical study. The CFD code was validated against experimental data by comparing pressure traces at different SOI’s. A parametric study on the effect of SOI on combustion has been carried out using the validated code. Two parameters, the combustion efficiency and CO emissions, were chosen to examine the effect of SOI on combustion, which showed good agreement between numerical results and experiments. Analysis of the in-cylinder flow field was carried out to identify the source of CO emissions at various SOI’s.

The need for improved understanding of new magnesium alloys for the automotive industry continues to grow as the application for these lightweight alloys expands to more demanding environments, particularly in drivetrain components. Their use at elevated temperatures, such as in transmission cases, presents a challenge because magnesium alloys generally have lower creep resistance than aluminum alloys currently employed for such applications. In this study, a new die cast magnesium alloy, MEZ, containing rare earth (RE) elements and zinc as principal alloying constituents, was examined for its bolt-load retention (BLR) properties. Preloads varied from 14 to 28 kN and test temperatures ranged from 125 to 175°C. At all test temperatures and preloads, MEZ retained the greatest fraction of the initial imposed preload when compared to the magnesium alloys AZ91D, AE42, AM50, and the AM50+Ca series alloys.