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The objective of this research is a detailed investigation of multiple injections in a highly-dilute diesel low temperature combustion (LTC) regime. This research concentrates on understanding the performance and emissions benefits of multiple injections via experiments and simulations in a 0.48L signal cylinder light-duty engine operating at 2000 r/min and 5.5 bar IMEP. Controlled experiments in the single-cylinder engine are then combined with three computational tools, namely heat release analysis of measured cylinder pressure, a phenomenological spray model using in-cylinder thermodynamics [1], and KIVA-3V Chemkin CFD computations recently tested at LTC conditions [2]. This study examines the effects of fuel split distribution, injection event timing, rail pressure, and boost pressure which are each explored within a defined operation range in LTC.

The objective of this research is a detailed investigation of unburned hydrocarbon (UHC) in a highly-dilute diesel low temperature combustion (LTC) regime. This research concentrates on understanding the mechanisms that control the formation of UHC via experiments and simulations in a 0.48L signal-cylinder light duty engine operating at 2000 r/min and 5.5 bar IMEP with multiple injections. A multi-gas FTIR along with other gas and smoke emissions instruments are used to measure exhaust UHC species and other emissions. Controlled experiments in the single-cylinder engine are then combined with three computational tools, namely heat release analysis of measured cylinder pressure, analysis of spray trajectory with a phenomenological spray model using in-cylinder thermodynamics [1], and KIVA-3V Chemkin CFD computations recently tested at LTC conditions [2].

Homogeneous charge compression ignition (HCCI) engines have the potential for high fuel efficiency and low NOx emissions. The major disadvantage of HCCI remains the narrow operating range. One way to extend the operating range of HCCI combustion to lower load is to inject part of the total fuel mass into the hot gas during recompression. With even lower engine load, part of the fuel can also be injected late in the main compression and ignited by a spark. The propagating flame further compresses the remaining fuel-air mixture until auto-ignition occurs (spark-assisted HCCI). In this study we investigated the effect of fuel reforming and spark assist in a gasoline engine with direct fuel injection and negative valve overlap. We performed experiments with different injection quantities and varying injection timings during recompression.

Beginning in 2007, heavy-duty engine manufacturers in the U.S. have been responsible for verifying the compliance of in-use vehicles with Not-to-Exceed (NTE) standards under the Heavy-Duty In-Use Testing Program (HDIUT). This in-use testing is conducted using Portable Emission Measurement Systems (PEMS) which are installed on the vehicles to measure emissions during field operation. A key component of the HDIUT program is the generation of measurement allowances which account for the relative accuracy of PEMS as compared to conventional laboratory-based measurement techniques. A program to determine these measurement allowances for gaseous emissions was jointly funded by the U.S. Environmental Protection Agency (EPA), the California Air Resources Board (CARB), and various member companies of the Engine Manufacturer's Association (EMA). The gaseous pollutants examined in the program were carbon monoxide (CO), non-methane hydrocarbons (NMHC), and oxides of nitrogen (NOx).

Under the U.S. Environmental Protection Agency's (EPA's) Heavy-Duty In-Use Testing (HDIUT) program, emission of non-methane hydrocarbons (NMHC), carbon monoxide (CO), and oxides of nitrogen (NOx) have been regulated using Portable Emissions Measurement Systems (PEMS) during in-use field operation for heavy-duty on-highway diesel engines with 2007 or later model year designations. As directed by the EPA, the Engine Manufacturers Association (EMA), and the California Air Resources Board (CARB), additive emission measurement accuracy margins (measurement allowances) were experimentally determined for HDIUT to account for the measurement differences between laboratory testing with laboratory grade equipment and in-use testing with PEMS. As part of a three-paper series, this paper summarizes the HDIUT measurement allowance program while focusing on the laboratory evaluations of the Sensors Inc. SEMTECH-DS PEMS.

Beginning in 2007, heavy-duty engine manufacturers in the U.S. have been responsible for verifying the compliance on in-use vehicles with Not-to-Exceed (NTE) standards under the Heavy-Duty In-Use Testing Program (HDIUT). This in-use testing is conducted using Portable Emission Measurement Systems (PEMS) which are installed on the vehicles to measure emissions during real-world operation. A key component of the HDIUT program is the generation of measurement allowances which account for the relative accuracy of PEMS as compared to more conventional, laboratory based measurement techniques. A program to determine these measurement allowances for gaseous emissions was jointly funded by the U.S. Environmental Protection Agency (EPA), the California Air Resources Board (CARB), and various member companies of the Engine Manufacturer's Association (EMA).

Low temperature combustion (LTC) strategies, which can mitigate emissions of particulate matter (PM) and nitrogen oxides (NOx) from diesel engines, typically have longer ignition delays compared to conventional diesel operation. With extended ignition delays, more time is available for premixing, which reduces PM formation. The effect of varying ignition delay on the spatial and temporal evolution of soot in LTC diesel jets is studied by imaging the natural soot luminosity, while the in-cylinder soot mass and temperature are measured using two-color soot thermometry. Ignition delay in the engine is controlled by adjusting the intake air temperature while keeping the same charge density at TDC. This allowed us to study sooting characteristics at various ignition delays while keeping the same diesel jet penetration for all the cases.

Due to the stringent requirements to reduce the tail pipe emissions of NOx, Selective Catalytic Reduction (SCR) systems are used to remove NOx using ammonia. When a urea solution is injected into the exhaust system, urea will undergo hydrolysis and decomposition reaction that produces ammonia. At the catalyst surface, ammonia will react with the exhaust gases to convert NOx into nitrogen, N2 and water, H2O. One of the challenging problems is to make sure the urea solution is available for the SCR system at cold start conditions. At extreme cold temperatures, the urea solution will begin to freeze at −12°C. At the start up of a vehicle under such low ambient temperatures, a heating system is used to provide the heat required for melting the frozen urea. Therefore, there will be a time lag between the vehicle start up and the availability of urea solution to the SCR system.

A systematic methodology has been employed to develop the Duratec 3.5L EcoBoost combustion system, with focus on the optimization of the combustion system including injector spray pattern, intake port design, piston geometry, cylinder head geometry. The development methodology was led by CFD (Computational Fluid Dynamics) modeling together with a testing program that uses optical, single-cylinder, and multi-cylinder engines. The current study shows the effect of several spray patterns on air-fuel mixing, in-cylinder flow development, surface wetting, and turbulence intensity. A few sets of injector spray patterns are studied; some that have a wide total cone angle, some that have a narrow cone angle and a couple of optimized injector spray patterns. The effect of the spray pattern at part load, full load and cold start operation was investigated and the methodology for choosing an optimized injector is presented.

Measurements of the soot emissions and engine operating parameters from a diesel engine during transient operation were used to investigate the influence of transient operation on the soot emissions, as well as to validate a realtime mean value soot model (MVSM, [1]) for transient operation. To maximize the temporal resolution of the soot emission and engine parameter measurements (in particular EGR), fast instruments were used and their dynamic responses characterized and corrected. During tip-in transients, an increase in the soot emissions was observed due to a short term oxygen deficit compared to steady-state operation. No significant difference was seen between steady-state and transient operation for acceleration transients. When the MVSM was provided with inputs of sufficient temporal resolution, it was capable of reproducing the qualitative and, in part, quantitative soot emission trends.

Ethyl tertiary butyl ether (ETBE) has been used as a high octane blending component since the early 1990's. However the strong interest in renewable energy has led to a dramatic increase in its use. This has also resulted in a substantial number of technical studies being carried out around the world to assess its performance with respect to vehicle performance, distribution system compatibility, environmental impact and toxicology. The purpose of this paper is to provide a comprehensive, up to date review of these data. Particular focus will be given to its positive impact on CO2 emissions.

The simultaneous reduction of engine-out nitrogen oxide (NOx) and particulate emissions via low-temperature combustion (LTC) strategies for compression-ignition engines is generally achieved via the use of high levels of exhaust gas recirculation (EGR). High EGR rates not only result in a drastic reduction of combustion temperatures to mitigate thermal NOx formation but also increases the level of pre-mixing thereby limiting particulate (soot) formation. However, highly pre-mixed combustion strategies such as LTC are usually limited at higher loads by excessively high heat release rates leading to unacceptable levels of combustion noise and particulate emissions. Further increasing the level of charge dilution (via EGR) can help to reduce combustion noise but maximum EGR rates are ultimately restricted by turbocharger and EGR path technologies.

Single cylinder optical engines are used for internal combustion (IC) engine research as they allow for the application of qualitative and quantitative non-intrusive, diagnostic techniques to study in-cylinder flow, mixing, combustion and emissions phenomena. Such experimental data is not only important for the validation of computational models but can also provide a detailed insight into the physical processes occurring in-cylinder which is useful for the further development of new combustion strategies such as gasoline homogeneous charge compression ignition (HCCI) and Diesel low temperature combustion (LTC). In this context, it is therefore important to ensure that the performance of optical engines is comparable to standard all-metal engines. A comparison of optical and all-metal engine combustion and emissions performance was performed within the present study.

Previous research has shown that elevating fuel injection pressure results in better air-fuel mixture formation, allowing for a further increase in maximum exhaust gas recirculation (EGR) rate while consequently reducing NOx emissions. The aim of this paper is to find out whether there is an optimum injection pressure for lowest soot-NOx emissions at a given boost pressure in high-speed diesel engines. Experiments are carried out on a single-cylinder research engine with a prototype common-rail system, capable of more than 200 MPa injection pressure. The effect of injection pressure on soot-NOx formation is investigated for a variety of boost conditions, representing the conditions of single to multi-stage turbocharger systems. Analysis of the data is performed at the application relevant soot to NOx ratio of approximately 1:10. It is observed that above a critical injection pressure, soot-NOx emissions are not reduced any further.

Two different types of mesh used for diesel combustion with the KIVA-4 code are compared. One is a well established conventional KIVA-3 type polar mesh. The other is a non-polar mesh with uniform size throughout the piston bowl so as to reduce the number of cells and to improve the quality of the cell shapes around the cylinder axis which can contain many fuel droplets that affect prediction accuracy and the computational time. This mesh is specialized for the KIVA-4 code which employs an unstructured mesh. To prevent dramatic changes in spray penetration caused by the difference in cell size between the two types of mesh, a recently developed spray model which reduces mesh dependency of the droplet behavior has been implemented. For the ignition and combustion models, the Shell model and characteristic time combustion (CTC) model are employed.

One reliable way to measure the research activity in the field of engine technology is through the number of patent applications that are submitted to different patent offices in the world. This paper offers a thorough statistical analysis of the innovation trends related to downsizing in Europe, USA, Japan, China and Korea in the field of internal combustion engines during the last 10 years, as seen by the European Patent Office. It demonstrates which technical fields (e.g. super- and turbocharging, direct fuel injection systems, hybrid technology, variable valve actuation, exhaust gas recirculation, etc.) are the most active, who are the most important players and which country attracts the highest number of applications. Subfields of certain technical fields are also analyzed. The technical fields discussed are chosen according to the International Patent Classification (IPC) scheme.

EGR coolers are effective to reduce NOx emissions from diesel engines due to lower intake charge temperature. EGR cooler fouling reduces heat transfer capacity of the cooler significantly and increases pressure drop across the cooler. Engine coolant provided at 40–90 C is used to cool EGR coolers. The presence of a cold surface in the cooler causes particulate soot deposition and hydrocarbon condensation. The experimental data also indicates that the fouling is mainly caused by soot and hydrocarbons. In this study, a 1-D model is extended to simulate particulate soot and hydrocarbon deposition on a concentric tube EGR cooler with a constant wall temperature. The soot deposition caused by thermophoresis phenomena is taken into account the model. Condensation of a wide range of hydrocarbon molecules are also modeled but the results show condensation of only heavy molecules at coolant temperature.

Noise concerns regarding snowmobiles have increased in the recent past. Current standards, such as SAE J192 are used as guidelines for government agencies and manufacturers to regulate noise emissions for all manufactured snowmobiles. Unfortunately, the test standards available today produce results with variability that is much higher than desired. The most significant contributor to the variation in noise measurements is the test surface. The test surfaces can either be snow or grass and affects the measurement in two very distinct ways: sound propagation from the source to the receiver and the operational behavior of the snowmobile. Data is presented for a known sound pressure speaker source and different snowmobiles on various test days and test surfaces. Relationships are shown between the behavior of the sound propagation and track interaction to the ground with the pass-by noise measurements.

A generalized MADYMO minor rear crash vehicle model with BioRIDII ATD was developed and validated using the mean response of previously published 12 km/h delta-V rear crash tests. BioRIDII simulation pelvis, thorax and head x-axis accelerations, as well as head y-axis angular acceleration, fell within corridors defining +/- one standard deviation of the mean BioRIDII crash test responses. Peak sagittal plane BioRIDII upper neck forces and moments in the simulation were on par with the mean values observed from the crash tests. After the model was validated for 12 km/h delta-V, the model was further exercised by performing simulations with (1) a Hybrid III 50th percentile occupant and (2) by reducing the pulse by 40% of its original value. Results indicate that this generalized minor rear crash model could be useful in accurately estimating occupant kinematics and kinetics in minor crashes up to at least 12 km/h delta-V as an alternative to expensive and time consuming crash testing.

This paper describes an effective integrated method for estimation of subject-specific mass, inertia tensor, and center of mass of individual body segments of a digital avatar for use with physics-based digital human modeling simulation environment. One of the main goals of digital human modeling and simulation environments is that a user should be able to change the avatar (from male to female to a child) at any given time. The user should also be able to change the various link dimensions, like lengths of upper and lower arms, lengths of upper and lower legs, etc. These customizations in digital avatar's geometry change the kinematic and dynamic properties of various segments of its body. Hence, the mass and center of mass/inertia data of the segments must be updated before simulating physics-based realistic motions. Most of the current methods use mass and inertia properties calculated from a set of regression equations based on average of some population.