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Far-side occupants are not addressed in current government regulations around the world even though they account for up to 40% of occupant HARM in side impact crashes. Consequently, there are very few crash tests with far-side dummies available to researchers. Sled tests are frequently used to replicate the dynamic conditions of a full-scale crash test in a controlled setting. However, in far-side crashes the complexity of the occupant kinematics is increased by the longer duration of the motion and by the increased rotation of the vehicle. The successful duplication of occupant motion in these crashes confirms that a sled test is an effective, cost-efficient means of testing and developing far-side occupant restraints or injury countermeasures.

This investigation addresses and evaluates: (1) belted drivers in frontal crashes; (2) crashes divided into low, medium, and high severity; (3) air-bag-equipped passenger vehicles separated into either model years 1985 - 1997 (with airbags) or model years 1998 - 2008; (4) rate of Harm as a function of crash severity and vehicle model year; and (5) injury patterns associated with injured body regions and the involved physical components, by vehicle model year. Comparisons are made between the injury patterns related to drivers seated in vehicles manufactured before 1998 and those manufactured 1998 or later. The purpose of this comparative analysis is to establish how driver injury patterns may have changed as a result of the introduction of more recent safety belt technology, advanced airbags, or structural changes.

For children seated next to the struck side, real-world crash outcome was determined for the rear-seat of passenger vehicles over the entire range of side impact crash severities. The method was first to calculate the actual risk for an occupant based on field data. The data sources were non-rollover, tow-away crashes from the 1997 - 2009 National Automotive Sampling System. By limiting the struck passenger vehicle to model year 1985 or newer, field data were identified for a total of 588 children. In all crashes, the child was seated in the rear-seat area on the struck side of the passenger vehicle. A matrix of MADYMO model simulations calculated the response of child dummies over the entire range of the field data. Age-dependent, moderate-to-serious (AIS ≥ 2) injury risk curves were derived and evaluated for children in side impact. Risks to the children were calculated by combining the derived child risk curves with the MADYMO model simulations.

Vehicle steering control can provide assistance to drivers for lane keeping, automated trajectory following, or more extreme evasive maneuvers. An active torque control steering system is designed using Linear Quadratic Regulator (LQR), and its performance was evaluated using the commercial software CARSIM. The system is developed to maintain a desired trajectory for the vehicle in performing evasive maneuvers to avoid imminent crash scenarios. In order to better understand the behavior of the system with different controllers, a simple bicycle model of the vehicle was developed, and an LQR controller was developed to control vehicle steering torque. The controller uses yaw angle, yaw rate, velocity, and position of the vehicle to generate the required steering torque to follow the desired trajectory. An observer was developed to estimate non-measured parameters. Trajectories are generated to follow a lane change before reaching the obstacle.

Battery packs for Hybrids, Plug-in Hybrids, and Electric Vehicles are assembled from a system of modules (sheets) with a tight sheet metal casing around them. Each module consists of an array of individual cells which vary in the composition of electrodes and separator from one manufacturer to another. In this paper a general procedure is outlined on the development of a constitutive and computational model of a cylindrical cell. Particular emphasis is placed on correct prediction of initiation and propagation of a tearing fracture of the steel can. The computational model correctly predicts rupture of the steel can which could release aggressive chemicals, fumes, or spread the ignited fire to the neighboring cells. The initiation site of skin fracture depends on many factors such as the ductility of the casing material, constitutive behavior of the system of electrodes, and type of loading.

The objective of this paper is to study the parameters affecting the evolution of “uncontrolled” regeneration in diesel particulate filters with fuel-borne catalyst (FBC) support with emphasis on the development of thermal stresses critical for filter durability. The study is based on experiments performed on engine dynamometer, corresponding to “worst-case” scenario, as well as on advanced, multi-dimensional mathematical modeling. A new 2-dimensional mathematical model is presented which introduces an additional dimension across the soot layer and wall. With this dimension it is possible to take into account the variability of catalyst/soot ratio in the layer and to compute intra-layer composition gradients. The latter are important since they induce interesting O2 diffusion phenomena, which affect the regeneration evolution.

The objective of this study is to explain the physical and chemical mechanisms involved in the operation of a catalyzed diesel particulate filter. The study emphasizes on the coupling between reaction and diffusion phenomena (with emphasis on NO2 “back-diffusion”), based on modeling and experimental data obtained on the engine dynamometer. The study is facilitated by a novel multi-dimensional mathematical model able to predict both reaction and diffusion phenomena in the filter channels and through the soot layer and wall. The model is thus able to predict the species concentration gradients in the inlet/outlet channels, in the soot layer and wall, taking into account the effect of NO2 back diffusion. The model is validated versus engine dyno measurements. Two sets of measurements are employed corresponding to low-temperature “controlled” regenerations as well as high-temperature “uncontrolled” conditions.

The National Highway Traffic Safety Administration (NHTSA) routinely measures the force exerted on the barrier in crash tests. Thirty-six load cells on the face of the rigid barrier measure the force. This study examines the load cell barrier data collected during recent years of NCAP testing to determine how it can be used to assess vehicle compatibility in vehicle-to-vehicle front-to-side crashes. The height of the center-of-force measured by the columns of load cells is proposed as a metric for quantitatively describing the geometric properties of the crash forces. For front-to-side crashes, the geometric and stiffness properties of frontal structures during the early stages of crush are applicable. Consequently, geometric and stiffness measurements at a crush of 125 mm are presented in this paper. This paper shows the range of the compatibility and stiffness parameters measured on cars, pickups, vans, and multi-purpose vehicles.

In real-world driving, the exhaust gas conditions in the particulate filter may induce incomplete filter regenerations. The implications of such partial regenerations are examined in this paper in terms of pressure drop and filter thermal loading. The methodology followed is based on a 2-D simulation model of the regeneration process. The model is initially fine-tuned and validated based on experimental results from engine bench testing. The validated model is subsequently employed to simulate a series of regenerations starting from different possible initial soot distribution patterns. The results are evaluated based on the calculated maximum thermal gradient in the filter that would produce the critical thermal stress for filter structural integrity. It is shown that the filter thermal loading can be significantly higher in case of initially non-uniform soot distribution.

The automotive industry is currently evaluating the gasoline particulate filter (GPF) as a potential technology to reduce particulate emissions from gasoline direct injection (GDI) engines. In this paper, several GPF design measures which were taken to obtain a filter with lower pressure drop when compared to our previous concept will be presented. Based on engine test bench and vehicle test results, it was determined some soot will accumulate on the GPF walls, resulting in an increase in pressure drop. However, the accumulated soot will be combusted under high temperature and high O₂ concentration conditions. In a typical vehicle application, passive regeneration will likely occur and a cycle of soot accumulation and combustion might be repeated in the actual driving conditions.

Diesel particulate filters (DPF) are a common component in emission-control systems of modern clean diesel vehicles. Several DPF materials have been used in various applications. Silicone Carbide (SiC) is common for passenger vehicles because of its thermal robustness derived from its high specific gravity and heat conductivity. However, a segmented structure is required to relieve thermal stress due to SiC's higher coefficient of thermal expansion (CTE). Cordierite (Cd) is a popular material for heavy-duty vehicles. Cordierite which has less mass per given volume, exhibits superior light-off performance, and is also adequate for use in larger monolith structures, due to its lower CTE. SiC and cordierite are recognized as the most prevalent DPF materials since the 2000's. The DPF traps not only combustible particles (soot) but also incombustible ash. Ash accumulates in the DPF and remains in the filter until being physically removed.

Diesel engines are more fuel efficient due to their high thermal efficiency, compared to gasoline engines and therefore, have a higher potential to reduce CO2 emissions. Since diesel engines emit higher amounts of Particulate Matter (PM), DPF systems have been introduced. Today, DPF systems have become a standard technology. Nevertheless, with more stringent NOx emission limits and CO2 targets, additional NOx emission control is needed. For high NOx conversion efficiency, SCR catalysts technology shows high potential. Due to higher temperature at the close coupled position and space restrictions, an integrated SCR concept on the DPFs is preferred. A high SCR catalyst loading will be required to have high conversion efficiency over a wide range of engine operations which causes high pressure for conventional DPF materials.

The research question investigated in this study is what are the key attributes of foot and ankle injury in the between-rail frontal crash? For the foot and ankle, what was the type of interior surface contacted and the type of resulting trauma? The method was to study with in-depth case reviews of NASS-CDS cases where a driver suffered an AIS=2 foot or ankle injury in between-rail crashes. Cases were limited to belted occupants in vehicles equipped with air bags. The reviews concentrated on coded and non-coded data, identifying especially those factors contributing to the injuries of the driver's foot/ankle. This study examines real-world crash data between the years 1997-2009 with a focus on frontal crashes involving 1997 and later model year vehicles. The raw data count for between-rail crashes was 732, corresponding to 227,305 weighted, tow-away crashes.

The William Lehman Injury Research Center has conducted multi-disciplinary investigations of one hundred seventy-eight crashes involving adult occupants protected by safety belts and air bags. In all cases, serious injuries were suspected. Nine cases involved serious heart injuries. These cases are not representative of crashes in general. However, when used in conjunction with National Accident Sampling System; Crashworthiness Data System (NASS/CDS) they provide insight into the most severe injuries suffered by restrained occupants in frontal crashes. Heart injuries are rare, but when they occur they are usually life threatening. NASS/CDS shows that heart injuries comprise about 0.2% of the injuries in frontal tow-away crashes. In the NHTSA file of Special Crash Investigations (SCI) of air bag cases, heart injuries are reported in 1% of the occupants over 15 years of age. Twenty-five percent of the fatally injured occupants had heart injuries, and 83% of those with heart injury died.

While the present air bag systems have been shown to be highly effective in high severity crashes, undesirable side effects have been reported in some low severity events. The inflation rate of the airbag during deployment has been cited as a factor which induces injuries. A rapid airbag deployment rate is advantageous to provide protection to occupants in severe crashes. On the other hand, airbag aggressivity associated with the high inflation rate can increase injuries in the lower severity crashes. The injury producing forces from the airbag increase as the occupant position becomes closer to the bag at the time of deployment. This paper describes the results of an analytical study to evaluate chest injury measures for reduced inflation rates of a Taurus type air bag in a variety of crash modes. A detailed nonlinear finite element model of an unfolding airbag and a 50th percentile male Hybrid III dummy are used in conjunction with a test buck to simulate frontal crashes.

In close-coupled catalytic converter applications, the exhaust gas mass flow may present fluctuations with a timescale in the order of milliseconds, as a result of periodic valve operation. Such flow pulsations are likely to affect catalytic converter performance, due to mass transfer limitations. A fully transient channel model is developed, to study pollutant conversion under pulsating flow conditions. This model is applied to evaluate the effect of pulsations in catalyst conversion. Firstly, the effect of flow pulsations during the warmed-up operation is studied. Then, we focus on the effect of pulsations during the light-off phase, during which significant temperature and therefore activity gradients are observed in the monolith. The new model is also used to assess the accuracy of the traditional “quasi-steady state” approach, when applied to simulate converters under pulsating flow.

Diesel particulate filters are today widely accepted as a viable technology for drastically reducing particulate emissions from diesel engines. Current applications are based on some form of catalytic assistance for the filter regeneration purposes, either in the form of a fuel borne catalyst or by employing catalyzed filters. This paper presents an experimental and computational study of the prevailing reaction mechanisms in the catalyst supported DPF systems. The knowledge of the soot reaction kinetics in uncatalyzed filters with O2 and NO2 is a prerequisite in this respect. Next, the reaction rates in the case of using a Ce-based fuel-borne catalyst are evaluated. Emphasis is given on the importance of oxygen diffusion effects during uncontrolled regeneration. Finally, the regeneration mechanisms in a catalyst coated filter are studied.

In order to use modeling as a predictive tool for real-world particulate filter designs (segmented filters, non-axisymmetric designs), it is necessary to develop reliable 3-dimensional models. This paper presents a 3 d modeling approach, which is validated against engine-bench measurements with both FBC and CDPF systems. Special emphasis is given to the prediction of the transient inlet flow distribution, which is realized without resorting to external CFD software. The experimental and modeling results illustrate the 3-d nature of the problem, induced by the heat capacity and conductivity effects of the cement layers. It is possible to predict the localization of regeneration in certain areas of the filter (partial regeneration), as a result of poor heat transfer to thermally isolated regions in the filter. The accuracy of the model was validated by extensive comparisons with temperature measurements in 30 positions inside the filters and at various operating conditions.

The possibility to employ a single-brick system with a catalyzed filter (CDPF) for the after-treatment of diesel engines is potentially a promising and cost-effective solution. In the first part of this paper, the effectiveness of a single brick CDPF system towards reducing the gaseous CO and HC emissions is investigated experimentally and computationally. The second part of the paper deals with the behavior of single brick catalyzed filters compared with two brick systems comprising an upstream oxidation catalyst. The main differences of the two systems are highlighted in terms of regeneration efficiency and thermal loading, based on simulation results. The modeling work is based on a 3-dimensional model of the catalyzed filter and an axi-symmetric model of the oxidation catalyst. Model validations are presented based on engine bench testing.

The adoption of the diesel engine EGR systems, and increased uses of alcohol in spark ignited engines require wear resistant and low maintenance valve trains. Silicon nitride ceramic inserts were pressureless-sintered and successfully die-cast in rocker arms contacting the overhead cams in the valve trains. As fired, the insert sliding surface was fine and precise, eliminating any further processing. The comosite structure was machined with the sliding surface as a reference plane. Beside inherent high wear resistance, these lighter inserts reduced inertial forces of the trains and the torque required to drive the cams. The hard, brittle ceramics and a softer, more elastic aluminum alloy made the structure more durable and reliable. The process of development includes characterization, screening, manufacturing and quality control of the materials, and determination of wear resistance and reliability for this new structure.