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Technical Paper

The Robustly-Safe Automated Driving System for Enhanced Active Safety

Road safety is one of the major concerns for automated vehicles. In order for these vehicles to interact safely and efficiently with the other road participants, the behavior of the automated vehicles should be carefully designed. Liu and Tomizuka proposed the Robustly-safe Automated Driving system (ROAD) which prevents or minimizes occurrences of collisions of the automated vehicle with other road participants while maintaining efficiency. In this paper, a set of design principles are elaborated as an extension of the previous work, including robust perception and cognition algorithms for environment monitoring and high level decision making and low level control algorithms for safe maneuvering of the automated vehicle.
Technical Paper

A Sequential Chemical Kinetics-CFD-Chemical Kinetics Methodology to Predict HCCI Combustion and Main Emissions

This study presents the development of a new HCCI simulation methodology. The proposed method is based on the sequential coupling of CFD analysis prior to autoignition, followed by multi-zone chemical kinetics analysis of the combustion process during the closed valve period. The methodology is divided into three steps: 1) a 1-zone chemical kinetic model (Chemkin Pro) is used to determine either the intake conditions at IVC to achieve a desired ignition timing or the ignition timing corresponding with given IVC conditions, 2) the ignition timing and IVC conditions are used as input parameters in a CFD model (Fluent 6.3) to calculate the charge temperature profile and mass distribution prior to autoignition, and 3) the temperature profile and mass distribution are fed into a multi-zone chemical kinetic model (Chemkin Pro) to determine the main combustion characteristics.
Technical Paper

An Initial Study on Monetary Cost Evaluation for the Design of Automotive Electrical Architectures

One of the many challenges facing electronic 1 system architects is how to provide a cost estimate related to design decisions over the entire life-cycle and product line of the architecture. Various cost modeling techniques may be used to perform this estimation. However, the estimation is often done in an ad-hoc manner, based on specific design scenarios or business assumptions. This situation may yield an unfair comparison of architectural alternatives due to the limited scope of the evaluation. A preferred estimation method would involve rigorous cost modeling based on architectural design cost drivers similar to those used in the manufacturing (e.g. process-based technical cost modeling) or in the enterprise software domain (e.g. COCOMO). This paper describes an initial study of a cost model associated with automotive electronic system architecture.
Technical Paper

Effect of Mixing on Hydrocarbon and Carbon Monoxide Emissions Prediction for Isooctane HCCI Engine Combustion Using a Multi-zone Detailed Kinetics Solver

This research investigates how the handling of mixing and heat transfer in a multi-zone kinetic solver affects the prediction of carbon monoxide and hydrocarbon emissions for simulations of HCCI engine combustion. A detailed kinetics multi-zone model is now more closely coordinated with the KIVA3V computational fluid dynamics code for simulation of the compression and expansion processes. The fluid mechanics is solved with high spatial and temporal resolution (40,000 cells). The chemistry is simulated with high temporal resolution, but low spatial resolution (20 computational zones). This paper presents comparison of simulation results using this enhanced multi-zone model to experimental data from an isooctane HCCI engine.
Technical Paper

A Mars Mission Simulation to Determine the Efficacy of 0.38 G as a Countermeasure to Microgravity Induced Bone Demineralization

Physiological effects of prolonged exposure to microgravity are a major concern when considering crew health and performance during an interplanetary mission. Among the most mission-critical of these deleterious effects are the changes to the skeletal system. Loss of bone mineral density (BMD) can be approximated for outbound and inbound transit portions of a human Mars mission. However, the effect of Martian gravity (0.38G) on the skeletal system is not well understood. This paper presents an experimental design to study bone demineralization of weight bearing bones during prolonged exposure to the skeletal unloading of microgravity and reduced gravity (0.38G) environments and its implications for a human Mars mission.
Technical Paper

Nanorobots for Mars EVA Repair

Current trends in technology indicate that nanometer-scale devices will be feasible within two decades. It is likely that NASA will attempt a manned Mars mission within the next few decades. Manned Mars activities will be relatively labor-intensive, presenting significant risk of damage to the Marssuit. We have investigated two possible architectures for nanotechnology applied to the problem of damage during Mars surface activity. Nanorobots can be used to actively repair damaged suit materials while an astronaut is in the field, reducing the need to return immediately to a pressurized area. Assembler nanorobots reproduce both themselves and the more specialized Marssuit Repair Nanorobots (MRN). MRN nanorobots operate as space-filling polyhedra to repair damage to a Marssuit. Both operate with reversible mechanical logic, though only assemblers utilize chemical data storage.
Technical Paper

Dynamics of Combustion in a Diesel Engine Under the Influence of Air/Fuel Ratio

The dynamic stage of combustion - the intrinsic process for pushing the compression polytrope away from the expansion polytrope to generate the indicator work output of a piston engine - was studied to reveal the influence of the air/fuel ratio on the effectiveness with which the fuel was utilized. The results of tests carried out for this purpose, using a 12 liter diesel engine, were reported last year [SAE 1999-01-0517]. Presented here is an analytic interpretation of the data obtained for part-load operation at 1200 and 1800 rpm. A solution is thus provided for an inverse problem: deduction of information on the dynamic features of the exothermic process of combustion from measured pressure record. Provided thereby, in particular, is information on the effectiveness with which fuel was utilized in the course of this process - a parameter reflecting the effect of energy lost by heat transfer to the walls.
Technical Paper

Refinement of Heat Release Analysis

The refinement of heat release analysis stems from the recognition that a combustion system is intrinsically non-linear. Thus, as appropriate for such an entity, its properties are expressed in terms of a thermochemical phase (or state) space, of which the thermodynamic aspects are exposed on a so-called Le Chatelier diagram, providing the fundamental background for the development of micro-electronic control to attain the most effective utilization of fuel. Implementation of this method of approach is illustrated by the analysis of the exothermic process taking place in two typical internal combustion engines, spark-ignition and diesel.
Technical Paper

Thermodynamic Properties of Methane and Air, and Propane and Air for Engine Performance Calculations

This is a continuation of the presentation of thermodynamic properties of selected fuel-air mixtures in chart form, suitable for utilization in engine performance calculations. Methane and propane, representative of natural gas and LPG are the two fuels considered. Using these charts, comparisons are made between the performance to be expected with these gaseous fuels compared to octane, as representative of gasoline. Reduced engine power is predicted and this is confirmed by experience of other investigators.
Technical Paper

Gas Turbine Combustion of Ammonia

A theoretical and experimental study was undertaken to establish whether or not parametric correlations could be satisfactorily applied to combustion of ammonia in gas turbine combustors. It was found that a usual parameter of the form I (Re)0.7 was satisfactory for establishing blowout limits in modeling. However, the attainable values of chemical loading I were at least an order of magnitude less than those attainable with hydrocarbon fuels.
Technical Paper

Thermodynamic Properities of Octane and Air for Engine Performance Calculations

A digital computer and special program were used, along with new thermodynamic data, to recalculate and extend the scope and range of the classic combustion gas charts of Hottel and co-workers. A series of hydrocarbon and nonhydrocarbon fuels was treated over a range of fuel-air ratios, with temperatures extended up to 7200 R and pressures up to 15,000 psia. This, the first paper of a series, incorporates the resulting charts for isooctane at four mixture ratios ranging from 20% lean to 40% rich. Auxiliary charts for inducted mixture properties determination and a set of sample calculations are also included.