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Technical Paper

Vehicle Trajectories After Intersection Collision Impact

The postcollision motion starts immediately upon completion of a collision impact where the vehicles obtain new sets of velocities through an exchange of momentum. Similitude with model study and fullscale automobile experiments indicate that the post-collision trajectory is essentially a plane motion, governed by inertia and tire friction. Trajectories depend on many parameters (such as tire friction coefficient, front wheel steering angle, vehicle geometrics, and whether wheels are locked or free to rotate) but not on the vehicle weight. Theoretical computation of trajectories are compared with experiments.
Technical Paper

The Performance Effects of Edge-Based Heat Transfer on Lithium-Ion Pouch Cells Compared to Face-Based Systems

Optimizing the hardware design and control strategies of thermal management systems (TMS) in battery packs using large format pouch cells is a difficult but important problem due to the limited understanding of how internal temperature distributions impact the performance and lifetime of the pack. Understanding these impacts is difficult due to the greatly varying length and time scales between the coupled phenomena, causing the need for complex and computationally expensive models. Here, an experimental investigation is performed in which a set of fixed one-dimensional temperature distributions are applied across the face of a Nickel-Cobalt-Manganese (NCM) cathode lithium ion pouch cell in order to study the performance impacts. Effects on the open circuit voltage (OCV), Ohmic resistance, bulk discharge and charge resistance and instantaneous power are investigated.
Technical Paper

Surface Acoustic Wave Microhygrometer

A microhygrometer has been developed at JPL's Microdevices Laboratory based on the principle of dewpoint/frostpoint detection. The surface acoustic wave device used in this instrument is approximately two orders of magnitude more sensitive to condensation than the optical sensor used in chilled-mirror hygrometers. In tests in the laboratory and on the NASA DC8, the SAW hygrometer has demonstrated more than an order of magnitude faster response than commercial chilled-mirror hygrometers, while showing comparable accuracy under steady-state conditions. Current development efforts are directed toward miniaturization and optimization of the microhygrometer electronics for flight validation experiments on a small radiosonde balloon.
Technical Paper

Reactive Regulation of Single-Lane Vehicle-Road Interactions

This paper presents a driver assistance system designed to minimize the effect of driver reaction time on lane and speed maintenance operations. Nearly-instantaneous correcting actions are provided through a hierarchical arrangement of behaviors, by avoiding the time lag associated with deliberative or planning steps found in many control algorithms. Concepts originating in the field of robotics, including artificial potential fields and behavior-based systems, are interpreted for application to automotive control, where vehicle dynamics places considerable practical constraints on implementation. Ideas found in the study of emergent behavior in nature provide continuous, non-stepwise control signals, suitable for additive corrective inputs at highway velocities. This approach is effective for a substantial subset of road automobiles operating over a variety of speeds.
Technical Paper

Potential for Closed Loop Air-Fuel Ratio Management of a Diesel Engine

The potential for improving the efficiency of a heavy duty turbocharged diesel engine by closed loop Air-Fuel Ratio (AFR) management has been evaluated. Testing conducted on a 12 liter diesel engine, and subsequent data evaluation, has established the feasibility of controlling the performance through electronic control of air management hardware. Furthermore, the feasibility of using direct in-cylinder pressure measurement for control feedback has been established. A compact and robust fiber optics sensor for measuring real time in-cylinder pressure has been demonstrated on a test engine. A preferred method for reducing the cylinder pressure data for control feedback has been established for continued development.
Technical Paper

Meeting Both ZEV and PNGV Goals with a Hybrid Electric Vehicle - An Exploration

This paper is written to provide information on the fuel efficiency, emissions and energy cost of vehicles ranging from a pure electric (ZEV) to gasoline hybrid vehicles with electric range varying from 30 mi (50km) to 100 mi (160km). The Federal government s PNGV and CARB s ZEV have different goals, this paper explores some possibilities for hybrid-electric vehicle designs to meet both goals with existing technologies and batteries. The SAE/CARB testing procedures for determining energy and emission performance for EV and HEV and CARB s HEV ruling for ZEV credit are also critically evaluated. This paper intends to clarify some confusion over the comparison, discussion and design of electric- hybrid- and conventional- vehicles as well.
Journal Article

Evaluation and Modification of Constant Volume Sampler Based Procedure for Plug-in Hybrid Electric Vehicle Testing

Plug-in hybrid electric vehicles (PHVs) consume both fossil fuel and grid electricity, which imposes emission testing challenges on the current constant volume sampler (CVS) test method. One reason is that in the charge-depleting cycle, PHVs having all-electric range operate the engine for a small portion of the traction energy need, causing the CVS to overdilute the exhaust gas. The other reason is that the dilution factor (DF) in the EPA calculation has an error caused by ignoring the CO₂ concentration in ambient air. This paper evaluates these challenges by testing a Toyota PHV on the industry standard CVS system combined with additional continuous sampling methodology for continuous diluents, smooth approach orifice (SAO) measurement for ambient air flow, and fuel flow meter (FFM) measurement for fuel consumption. The current EPA DF can produce an error resulting in higher mass calculation.
Technical Paper

Evaluating Particulate Emissions from a Flexible Fuel Vehicle with Direct Injection when Operated on Ethanol and Iso-butanol Blends

The relationship between ethanol and iso-butanol fuel concentrations and vehicle particulate matter emissions was investigated. This study utilized a gasoline direct injection (GDI) flexible fuel vehicle (FFV) with wall-guided fueling system tested with four fuels, including E10, E51, E83, and an iso-butanol blend at a proportion of 55% by volume. Emission measurements were conducted over the Federal Test Procedure (FTP) driving cycle on a chassis dynamometer with an emphasis on the physical and chemical characterization of particulate matter (PM) emissions. The results indicated that the addition of higher ethanol blends and the iso-butanol blend resulted in large reductions in PM mass, soot, and total and solid particle number emissions. PM emissions for the baseline E10 fuel were characterized by a higher fraction of elemental carbon (EC), whereas the PM emissions for the higher ethanol blends were more organic carbon (OC) in nature.
Journal Article

Electrical Architecture Optimization and Selection - Cost Minimization via Wire Routing and Wire Sizing

In this paper, we propose algorithms for cost minimization of physical wires that are used to connect electronic devices in the vehicle. The wiring cost is one of the most important drivers of electrical architecture selection. Our algorithms perform wire routing from a source device to a destination device through harnesses, by selecting the optimized wire size. In addition, we provide optimized splice allocation with limited constraints. Based on the algorithms, we develop a tool which is integrated into an off-the-shelf optimization and workflow system-level design tool. The algorithms and the tool provide an efficient, flexible, scalable, and maintainable approach for cost analysis and architecture selection.
Technical Paper

Easily Verifiable Adaptive Sliding Mode Controller Design with Application to Automotive Engines

Verification and validation (V&V) are essential stages in the design cycle of industrial controllers to remove the gap between the designed and implemented controller. In this study, a model-based adaptive methodology is proposed to enable easily verifiable controller design based on the formulation of a sliding mode controller (SMC). The proposed adaptive SMC improves the controller robustness against major implementation imprecisions including sampling and quantization. The application of the proposed technique is demonstrated on the engine cold start emission control problem in a mid-size passenger car. The cold start controller is first designed in a single-input single-output (SISO) structure with three separate sliding surfaces, and then is redesigned based on a multiinput multi-output (MIMO) SMC design technique using nonlinear balanced realization.
Technical Paper

Development of a Carbon/Epoxy Body for a High Performance Vehicle

Considerations follow [1] on the development of the carbon/epoxy body of the Lamborghini Murcièlago. Laminate lay-up and material selection for stiffness criteria are reviewed. Engineering solutions for tooling operations in order to achieve class A surface certification are analyzed. Design for environmental aging is also discussed and accelerated degradation testing methods are described. Finally, the program that lead to the adoption of hybrid adhesive bonding as sole method of joining the composite body components to the tubular steel frame is reviewed.
Technical Paper

Development and Testing of a ESM/PCM Heat Sink

To meet pulse power mode component cooling application needs, we developed, fabricated and tested a concept to use energy storage material and phase change material to enhance the heat dissipation of a conventional heat sink. Test results demonstrated the ESM/PCM heat sink has unique thermal performance. Under the same working condition, the peak temperature of ESM/PCM heat sink is 1.5°C lower than of a conventional heat sink. An optimized design can lead to a significant weight reduction for the heat sink in applications with high peak load and low duty power cycle power.
Journal Article

A Robust Lane-Keeping ‘Co-Pilot’ System Using LBMPC Method

To provide a feasible transitional solution from all-by-human driving style to fully autonomous driving style, this paper proposed concept and its control algorithm of a robust lane-keeping ‘co-pilot’ system. In this a semi-autonomous system, Learning based Model Predictive Control (LBMPC) theory is employed to improve system's performance in target state tracking accuracy and controller's robustness. Firstly, an approximate LTI model which describes driver-vehicle-road closed-loop system is set up and real system's deviations from the LTI system resulted by uncertainties in the model are regarded as bounded disturbance. The LTI model and bounded disturbances make up a nominal model. Secondly, a time-varying model which is composed of LTI model and an ‘oracle’ component is designed to observe the possible disturbances numerically and it is online updated using Extended Kalman Filter (EKF).
Technical Paper

A Fuel Control Strategy that Optimizes the Efficiency of a Direct-Methanol Fuel Cell in an Automotive Application

For automotive applications, it is necessary to maximize the fuel conversion efficiency of a PEM direct-methanol fuel cell (DMFC) over the broadest possible dynamic range of power. The research reported here critically examines the efficiency of the DMFC stack when operated over a broad power range. This research establishes a basis for a control strategy that simultaneously: optimizes DMFC fuel conversion efficiency versus power level, leads into a system level optimization of efficiency vs. power, and provides an operational strategy for controlling a direct-methanol fuel cell for maximum fuel efficiency from minimum to maximum power demand. First, there is an explanation of the experimental conditions used to obtain the DMFC experimental data that is reported and analyzed. Next the DMFC methanol crossover phenomenon is discussed and characterized. Then the conceptual framework for the optimization of fuel conversion efficiency is presented.
Journal Article

A Complete Assessment of the Emissions Performance of Ethanol Blends and Iso-Butanol Blends from a Fleet of Nine PFI and GDI Vehicles

Biofuels, such as ethanol and butanol, have been the subject of significant political and scientific attention, owing to concerns about climate change, global energy security, and the decline of world oil resources that is aggravated by the continuous increase in the demand for fossil fuels. This study evaluated the potential emissions impacts of different alcohol blends on a fleet of modern gasoline vehicles. Testing was conducted on a fleet of nine vehicles with different combinations of ten fuel blends over the Federal Test Procedure and Unified Cycle. The vehicles ranged in model year from 2007-2014 and included four vehicles with port fuel injection (PFI) fueling and five vehicles with direct injection (DI) fueling. The ten fuel blends included ethanol blends at concentrations of 10%, 15%, 20%, 51%, and 83% by volume and iso-butanol blends at concentrations of 16%, 24%, 32%, and 55% by volume, and an alcohol mixture giving 10% ethanol and 8% iso-butanol in the final blend.