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Technical Paper

Sensitivity of Accident Reconstruction Calculations

A number of simplistic formulae, based on particle dynamics, energy, and momentum methods are routinely employed by accident reconstructionists to calculate vehicle speeds immediately prior to impact. It is almost always the case that scene evidence and other information regarding important variables involved in such equations must either be estimated or can be measured only in an approximate way. ...Example problems illustrate the difficulties faced by accident reconstructionists as they grapple with incomplete and/or estimated values for important variables, and with the inherent sensitivity of some of the calculations to seemingly small variations in variable magnitudes.
Journal Article

Automatic Transmission Gear Ratio Optimization and Monte Carlo Simulation of Fuel Consumption with Parasitic Loss Uncertainty

An enterprise approach for vehicle fleet balancing of fuel consumption objectives based upon selection of automatic transmission gearing strategy is presented. Monte Carlo simulations for the influence of parasitic loss uncertainty for the automatic transmissions selected from the generalized DOE were conducted to determine the range of fuel consumption that might be realized in production. ...Automatic transmission gearing parameter selection was unaffected by the variation introduced by the Monte Carlo simulations, but did show fuel consumption performance to vary upwards of 9 g CO2/km depending on applications and to have a direct impact on powertrain operating parameters.
Technical Paper

Particulate Matter Formation Dynamics as Investigated by Ultra-Accelerated Quantum Chemical Molecular Dynamics Coupled with Canonical Monte Carlo Method

Suppression or reduction of soot emissions is an important goal in the development of automotive engines for environmental and human health purposes. A better understanding at the molecular level of the formation process of soot particles resulting from collision and aggregation of smaller particles made of Polycyclic Aromatic Hydrocarbon (PAH) is needed. In addition to experiments, computational methods are efficient and valuable tools for this purpose. As a first step in our detailed computational chemistry study, we applied Ultra-Accelerated Molecular Dynamics (UAQCMD) and Canonical Monte-Carlo (CMC) methods to investigate the nucleation process. The UA-QCMD can calculate chemical reaction dynamics 107 times faster than conventional first principle molecular dynamics methods, while CMC can calculate equilibrium properties at various temperatures, pressures, and chemical compositions.
Technical Paper

Application of Signal Reconstruction to On-Road Emissions Testing

Data was taken from these analyzers and passed, off-line, through the reconstruction filter. In addition, part of the Federal Urban Driving Schedule was simulated on the chassis dynamometer and emissions data collected from the test vehicle.
Technical Paper

Signal Reconstruction Applied to a Fast Response Flame Ionisation Detector

The Fast-response Flame Ionisation Detector is used to measure levels of un-burnt hydrocarbons in the cylinder and exhaust of engines. Its fast response allows uHC emission processes to be resolved within an engine cycle. This paper describes a method for obtaining even greater detail by post-processing the output of the device using a Finite-Impulse Response (FIR) digital filter. The specification of the filter can be obtained by understanding the flow regimes within the sampling system. Examples from in-cylinder and exhaust sampling are presented with suggestions for implementation and further improvement.
Technical Paper

Performance of a Non-Lacerative Windshield in Case of Accident and Under Environmental Conditions

The four-layer laminated Securiflex windshield has been tested in simulated collisions at the Wayne State University up to 40 mph Barrier Equivalent Velocities, to demonstrate that it causes no laceration. has been exposed to usual and extreme environmental conditions to demonstrate its serviceability in field use. The new windshield consists of a conventional laminated construction (glass/high penetration resistant interlayer/glass) combined with a 0.5 mm innerlayer of plastic. Glass is used on the outer surface of the windshield to withstand the abrasion and scratching of sand, windshield wipers and cleaning. The laminated construction prevents penetration and provides a pocket or cushion action to decelerate the head without injury. The innerlayer is made of a special plastic film which protects the face of the occupants against laceration and eye injury during head impact.
Technical Paper

Reconstruction of the Cylinder Pressure from Vibration Measurements for Prediction of Exhaust and Noise Emissions in Ethanol Engines

There are growing demands for condition monitoring of IC engines, and therefore any method in order to improve the performance of the engines ought to be evaluated. This paper proposes a new approach for the prediction and optimisation of noise and exhaust emissions in IC engines. The idea is to reconstruct the cylinder pressure from vibration measurements on the engine surface by using the complex cepstrum method [3, 4]. The reconstructed cylinder pressure is further used as input in Multivariate models, based on cylinder pressure, for estimating noise and exhaust emissions. This paper demonstrates the applicability of the method for modelling of noise and exhaust emissions
Technical Paper

Validity of Low Ventilation for Accident Processing with Hydrogen Leakage from Hydrogen-Fuelled Vehicle

Appropriate emergency response information is required for first responder before hydrogen fuel cell vehicles will become widespread. This paper investigates experimentally the hydrogen dispersion in the vicinity of a vehicle which accidentally releases hydrogen horizontally with a single volumetric flow of 2000 NL/min in the under-floor section while varying cross and frontal wind effects. This hydrogen flow rate represents normally a full throttle power condition. Forced wind was about maximum 2 m/s. The results indicated that the windward side of the vehicle was safe but that there were chiefly two areas posing risks of fire by hydrogen ignition. One was the leeward side of the vehicle's underbody where a larger region of flammable hydrogen dispersion existed in light wind than in windless conditions. The other was the area around the hydrogen leakage point where most of the leaked hydrogen remained undiffused in an environment with a wind of no stronger than 2 m/s.
Technical Paper

Parametric Investigation of Ice Shedding from a Business Jet Aircraft

This methodology combines experimental aerodynamic characteristics of ice fragments, computational fluid dynamics, trajectory analysis and the Monte Carlo method to provide probability maps of shed particle footprints at desired locations. ...Trajectories of a rectangular plate shed from the wing and windshield of a generic business jet are presented in this paper. Monte Carlo simulations for two aircraft speeds, three angles of attack and one yaw angle are also included to demonstrate the effect of shed location and initial particle orientation on plate trajectory path. ...In most of the Monte Carlo simulations, however, it was found that a considerable amount of fragments may collide with the fuselage.
Technical Paper

Uncertainties in Measurements of Emissions in Chassis Dynamometer Tests

Data from one steady state propane injection test and a transient driving cycle are used to compare results from our analysis and Monte Carlo simulation. It is found that the Monte Carlo simulation shows good agreement with the results from the uncertainty analysis. ...A computer generated Monte Carlo simulation is used to validate the present analysis. Data from one steady state propane injection test and a transient driving cycle are used to compare results from our analysis and Monte Carlo simulation.
Technical Paper

Limitations of Real-Time Engine-Out NOx Estimation in Diesel Engines

In our paper we analyze the effect of input uncertainty on the accuracy of engine-out NOx estimates via a numerical Monte Carlo simulation and show that this effect can be significant. Even though our model is based on an in-cylinder pressure sensor, this sensor is limited in its capability to reduce the effect of other measured inputs on the model.
Technical Paper

Modeling of the Shuttle Tissue-Equivalent Proportional Counters Using Computer Automated Design Techniques and Radial Frequency Distributions

The response model considers the spatial restriction on the mean-energy imparted and the variance for direct particle effects and combines the radial distribution of the electron energy and flux about incoming ions with the distribution of electron frequencies from Monte Carlo simulations. The latter model accounts for secondary electrons entering the sensitive area of the TEPC.
Technical Paper

Ice Crystal Ingestion in a Turbofan Engine

A through-flow based Monte Carlo particle trajectory simulation is used to calculate the ice crystal paths in the low pressure compressor of a high bypass ratio turbofan engine.