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Technical Paper

Class 8 Truck Investigation Comparing Wind Tunnel Test to Simulated Open Road Performance Using CFD

2018-04-15
2018-01-5010
Abstract Development of new, competitive vehicles in the context of stricter regulations to reduce greenhouse gas emissions and increase fuel economy is driving OEM of commercial vehicles to further explore options for reducing aerodynamic drag in a real-world setting. To facilitate this in regards to the aerodynamics of a vehicle, virtual design methods such as CFD are often used to compliment experiments to help reduce physical testing time and costs. Once validated against experiments, CFD models can then act as predictive models to help speed development. In this paper, a wind tunnel experiment of a Class 8 truck is compared to a CFD simulation which replicates said experiment, validating the CFD model as a predictive tool in this instance. CFD is then used to evaluate the drag and flow around the vehicle in an open road scenario, and the results between the open road and wind tunnel scenarios are compared.
Paper

The Use of Imaging for Powder Metal Characterization and Contamination Identification

2018-04-05
WP-0008
As AM technologies are being used with higher frequencywithin the automotive and aerospace industries, the interest in powder characterization and contaminant identification is growing—especially for suppliers looking to gain entry into these highly regulated industries. Standards for powder materials and methods used for aerospace applications are still be developed, and regulatory agencies such as the Federal Aviation Administration have been requesting that standards be developed as guidance for the industry. Methods such as CCSEM and HLS could be viable options for suppliers needing to adhere to a powder specification by demonstrating compliance. Solutions exist to integrate such methods into a production environment as exemplified by RJ Lee Group.
Technical Paper

Parametric Study and Prediction of Lubrication Oil Film Thickness in Sliding and Rolling Interface Valve Trains

2018-04-03
2018-01-0931
Abstract To achieve acceptable valve train lubrication with low viscosity oil is challenging. Understanding the effect of valve train design parameter on valve train lubrication is important. In this study rocker arm valve train mechanism is analyzed to check the influence of valve train design parameters on lubrication at cam and rocker face interface. In valve train lubrication, lubrication oil film thickness play important role in valve train wear and friction. Main objective is to maintain acceptable oil film thickness at peak valve lift and minimizing the duration of critical minimum oil film thickness at cam flank to avoid wear at cam/ roller rocker follower interface when using low viscosity oil. Cam nose wear effect the engine performance and wear at cam flank change the dynamic characteristics of valve train.
Technical Paper

Influence of Oncoming Light Exposure on Safety Outcomes in a Naturalistic Driving Study

2018-04-03
2018-01-1039
Abstract Recent naturalistic driving studies provide a useful means for gathering information about the potential role of lighting in driving safety. The Naturalistic Driving Study carried out through the Strategic Highway Research Program 2 (SHRP2) includes real-time driving data for crashes, near-crashes and baseline driving events for more than 3000 drivers across the United States. Among the data collected are oncoming illuminance recordings that can be used to estimate glare exposure for the drivers in the study. Data for crash events occurring at night were compared to those for baseline driving under similar conditions and by drivers of similar ages. The resulting light exposure data indicate that oncoming glare is likely to be only a very small factor associated with nighttime crashes, but that the influence of glare may increase for older drivers.
Technical Paper

Automotive Crashworthiness Design Optimization Based on Efficient Global Optimization Method

2018-04-03
2018-01-1029
Abstract Finite element (FE) models are commonly used for automotive crashworthiness design. However, even with increasing speed of computers, the FE-based simulation is still too time-consuming when simulating the complex dynamic process such as vehicle crashworthiness. To improve the computational efficiency, the response surface model, as the surrogate of FE model, has been widely used for crashworthiness optimization design. Before introducing the surrogate model into the design optimization, the surrogate should satisfy the accuracy requirements. However, the bias of surrogate model is introduced inevitably. Meanwhile, it is also very difficult to decide how many samples are needed when building the high fidelity surrogate model for the system with strong nonlinearity. In order to solve the aforementioned problems, the application of a kind of surrogate optimization method called Efficient Global Optimization (EGO) is proposed to conduct the crashworthiness design optimization.
Technical Paper

Mode-shifting Minimization in a Power Management Strategy for Rapid Component Sizing of Multimode Power Split Hybrid Vehicles

2018-04-03
2018-01-1018
Abstract The production of multi-mode power-split hybrid vehicles has been implemented for some years now and it is expected to continually grow over the next decade. Control strategy still represents one of the most challenging aspects in the design of these vehicles. Finding an effective strategy to obtain the optimal solution with light computational cost is not trivial. In previous publications, a Power-weighted Efficiency Analysis for Rapid Sizing (PEARS) algorithm was found to be a very promising solution. The issue with implementing a PEARS technique is that it generates an unrealistic mode-shifting schedule. In this paper, the problematic points of PEARS algorithm are detected and analyzed, then a solution to minimize mode-shifting events is proposed. The improved PEARS algorithm is integrated in a design methodology that can generate and test several candidate powertrains in a short period of time.
Technical Paper

Variability in Circumstances Underlying Pedal Errors: An Investigation Using the National Motor Vehicle Crash Causation Survey

2018-04-03
2018-01-0493
Abstract Pedal errors have been widely reported as a leading cause of unintended acceleration (UA) incidents for several decades. Many governmental and scientific studies have attempted to characterize the rate of pedal errors leading to UA incidents using data from the North Carolina Crash Database. These data, however, are limited for various reasons, including the absence of an in-depth investigation of causal factors contributing to the accident. To further examine the rate of UA incidents related to pedal error, we utilized the National Motor Vehicle Crash Causation Survey (NMVCCS), a nationally representative sample of 5,471 crashes that occurred between 2005 and 2007. Using a targeted keyword search, we identified 48 potential pedal errors (30 driver-admitted), providing a national estimate of 17,919 pedal errors.
Technical Paper

The Color Specification of Surrogate Roadside Objects for the Performance Evaluation of Roadway Departure Mitigation Systems

2018-04-03
2018-01-0506
Abstract Roadway departure mitigation systems for helping to avoid and/or mitigate roadway departure collisions have been introduced by several vehicle manufactures in recent years. To support the development and performance evaluation of the roadway departure mitigation systems, a set of commonly seen roadside surrogate objects need to be developed. These objects include grass, curbs, metal guardrail, concrete divider, and traffic barrel/cones. This paper describes how to determine the representative color of these roadside surrogates. 24,762 locations with Google street view images were selected for the color determination of roadside objects. To mitigate the effect of the brightness to the color determination, the images not in good weather, not in bright daylight and under shade were manually eliminated. Then, the RGB values of the roadside objects in the remaining images were extracted.
Technical Paper

Sodium Cooling Efficiency in Hollow Valves for Heavy Duty Engines

2018-04-03
2018-01-0368
Abstract As a consequence of the ongoing evolution of engines, where performance is continuously improving and the use of alternative fuels is being adopted by many engine manufacturers, thermal working conditions of the exhaust valves are increasingly critical. In order to better resist the higher temperature levels of the exhaust gases, current development ranges from improvement of the cooling concept for the overall system, new materials for valve set components up to the upgrade of the exhaust manifold material. Change in the design of several valvetrain components due to the increased thermal loads is a logical consequence of this technical evolution process. Hollow exhaust valves filled with Sodium (Na) are a known technology that is widely used in passenger car engines to improve thermal behavior and to avoid the need to change to expensive materials (Ni-base alloys).
Technical Paper

Analysis and Opportunities for Solar Photovoltaics Technologies on Electrified Vehicles

2018-04-03
2018-01-0426
Abstract The objective of this paper is to provide a comprehensive investigation of the opportunities and applications of using solar panels in electrified vehicles. The use of photovoltaic (PV) panels as an auxiliary energy source of on-board fuel in plug-in hybrid electric vehicles (PHEVs), full hybrid electric vehicles (FHEVs), and battery electric vehicles (BEVs) is investigated. The electrical architectures and the benefits of various possible applications are presented, such as active vehicle cabin ventilation, charging the low voltage battery, charging the high voltage (HV) traction battery to extended driving ranges. In addition, a novel solar powered battery thermal management system is developed to cool and heat the HV battery in extreme temperature environments. Here, the analysis is based on experimental and modeling results to relate the HV battery temperature with HV battery installation locations within the vehicle before and after using solar panel.
Technical Paper

Modelling of a Coupled Catalyst and Particulate Filter for Gasoline Direct Injection Engines

2018-04-03
2018-01-0986
Abstract There has been extensive research in the development of Gasoline Direct Injection ‘GDI’ engine exhaust systems with the aim of reducing engine-out emissions and meeting legislation requirements. Depending on the room available for packaging the exhaust system, the engine may be equipped with a single catalyst or two catalysts one close to the engine and another one located further downstream. With the strict particulate matter emission regulations of GDI engine, the engine has to be equipped with a Gasoline Particulate Filter ‘GPF’ in addition to the Closed Coupled Catalyst ‘CCC’. The common practice is to have the GPF further downstream the catalyst. In this paper, an assessment method is carried for a new design of a hot end exhaust system. The new design brings the GPF closer to ‘CCC’ to be packed in the same enclosure. The gas flow velocity and pressure distributions inside the exhaust system are identified using CFD for a uniform exhaust gas flow inlet conditions.
Technical Paper

The Development of Skutterudite-Based Thermoelectric Generators for Vehicles

2018-04-03
2018-01-0788
Abstract With the continuing improvements to thermoelectric (TE) materials and systems, their potential for both energy recovery and thermal management is increasingly apparent. Recent developments in materials and notably Skutterudites have allowed materials to be matched much more closely to the working temperatures of a light duty power-train. The choice of TE materials remains a substantial question in the design of a thermoelectric generator (TEG). While the quest for improvements in materials performance continues, the work reported in this paper is characterized by the decision to focus on the refinement of one class of TE materials: Skutterudites. In parallel, the engineering work on the integration of the TE materials into a heat exchanger could continue and be focused on the properties of this class of material. Skutterudites offer the combination of a high working temperature and a competitive electrical output (defined by ZT, the figure of merit).
Technical Paper

Simulation Research of a Hydraulic Interconnected Suspension Based on a Hydraulic Energy Regenerative Shock Absorber

2018-04-03
2018-01-0582
Abstract The current paper proposes a hydraulic interconnected suspension system (HIS) based on a hydraulic energy-regenerative shock absorber (HESA) comparatively with the passive suspensions. The structure and working principles of the HIS system are introduced in order to investigate the damping performance and energy regeneration characteristics of the proposed system. Then, the dynamic characteristics of the HIS-HESA system have been investigated based on a 4-DOF longitudinal half vehicle model. In the simulation, two different road inputs were used in the dynamic characterization of the HIS-HESA; the warp sinusoidal excitation, and the random road signal. In addition, a comparative analysis was provided for the dynamic responses of the half vehicle model for both the HIS-HESA and the conventional suspension. Furthermore, a parametric analysis of the HIS-HESA has been carried out highlining the key parameters that have a remarkable effect on the HIS-HESA performance.
Technical Paper

Multidisciplinary Optimization of Auto-Body Lightweight Design Using Hybrid Metamodeling Technique and Particle Swarm Optimizer

2018-04-03
2018-01-0583
Abstract Because of rising complexity during the automotive product development process, the number of disciplines to be concerned has been significantly increased. Multidisciplinary design optimization (MDO) methodology, which provides an opportunity to integrate each discipline and conduct compromise searching process, is investigated and introduced to achieve the best compromise solution for the automotive industry. To make a better application of MDO, the suitable coupling strategy of different disciplines and efficient optimization techniques for automotive design are studied in this paper. Firstly, considering the characteristics of automotive load cases which include many shared variables whereas rare coupling variables, a multilevel MDO coupling strategy based on enhanced collaborative optimization is studied to improve the computational efficiency of MDO problems.
Technical Paper

Motion Cueing Algorithm for a 9 DoF Driving Simulator: MPC with Linearized Actuator Constraints

2018-04-03
2018-01-0570
Abstract In times when automated driving is becoming increasingly relevant, dynamic simulators present an appropriate simulation environment to faithfully reproduce driving scenarios. A realistic replication of driving dynamics is an important criterion to immerse persons in the virtual environments provided by the simulator. Motion Cueing Algorithms (MCAs) compute the simulator’s control input, based on the motions of the simulated vehicle. The technical restrictions of the simulator’s actuators form the main limitation in the execution of these input commands. Typical dynamic simulators consist of a hexapod with six degrees of freedom (DoF) to reproduce the vehicle motion in all dimensions. Since its workspace dimensions are limited, significant improvements in motion capabilities can be achieved by expanding the simulator with redundant DoF by means of additional actuators.
Technical Paper

Investigation of Macroscopic as well as Microscopic Spray Behavior of Multi-hole GDI Injector under Engine Like Hot Injector Body Conditions

2018-04-03
2018-01-0280
Abstract Fuel injection is one of the most important processes in the GDI engine operation. Depending when the fuel is injected in the GDI engine, it can either work in homogeneous or stratified charge mode. In case of real engine operation, fuel injector gets heated due to heat transfer from the in-cylinder hot burnt gases. This can significantly affect the spray characteristics and ultimately the engine performance. In the present work, engine like hot injector body conditions have been created in a constant volume spray chamber. Five different temperatures conditions (23 °C, 100 °C, 150 °C, 200 °C and 250 °C) were created to study the effect of hot fuel conditions. Schlieren and Shadowgraph techniques were used to capture the vapor and the liquid phase of Isooctane, whereas droplet size information was measured using the Phase Doppler Particle Analyzer (PDPA).
Technical Paper

Using a DNS Framework to Test a Splashed Mass Sub-Model for Lagrangian Spray Simulations

2018-04-03
2018-01-0297
Abstract Numerical modeling of fuel injection in internal combustion engines in a Lagrangian framework requires the use of a spray-wall interaction sub-model to correctly assess the effects associated with spray impingement. The spray impingement dynamics may influence the air-fuel mixing and result in increased hydrocarbon and particulate matter emissions. One component of a spray-wall interaction model is the splashed mass fraction, i.e. the amount of mass that is ejected upon impingement. Many existing models are based on relatively large droplets (mm size), while diesel and gasoline sprays are expected to be of micron size before splashing under high pressure conditions. It is challenging to experimentally distinguish pre- from post-impinged spray droplets, leading to difficulty in model validation.
Technical Paper

ECN Spray G Injector: Assessment of Numerical Modeling Accuracy

2018-04-03
2018-01-0306
Abstract Gasoline Direct Injection (GDI) is a leading technology for Spark Ignition (SI) engines: control of the injection process is a key to design the engine properly. The aim of this paper is a numerical investigation of the gasoline injection and the resulting development of plumes from an 8-hole Spray G injector into a quiescent chamber. A LES approach has been used to represent with high accuracy the mixing process between the injected fuel and the surrounding mixture. A Lagrangian approach is employed to model the liquid spray. The fuel, considered as a surrogate of gasoline, is the iso-octane which is injected into the high-pressure vessel filled with nitrogen. The numerical results have been compared against experimental data realized in the optical chamber. To reveal the geometry of plumes two different imaging techniques have been used in a quasi-simultaneous mode: Mie-scattering for the liquid phase and schlieren for the gaseous one.
Technical Paper

A Novel Approach for High Frequency Interior Noise Prediction

2018-04-03
2018-01-0148
Abstract Since Statistical Energy Analysis (SEA) is based on lumped parameters, acoustic responses predicted by SEA are spatially discontinuous. However, in many practical applications, the ability to predict spatially continuous energy flow is useful for guiding the design of systems with improved acoustical characteristics. A new approach, utilizing integral equations derived from energy flow concepts, is developed to predict the continuous variation of acoustic field such as sound pressure level in the interior of acoustic domains using structural response predicted by SEA. The computer code developed based on energy flow boundary integral equations is initially validated by analyzing sound propagation in a duct.
Technical Paper

Correlation and Verification of a Tractor Cab Model Using Statistical Energy Analysis

2018-04-03
2018-01-0142
Abstract A model of a tractor cab was built using Statistical Energy Analysis (SEA) best practices. In this paper, it is shown how this model was correlated using p/Q transfer functions measured in the lab with a volume velocity source. After correlation, the model was excited using acoustic loads measured during tractor operation. It was found that the data predicted by the model is in good agreement with the data measured inside the cabin during this test. It was concluded that SEA can be used as an engineering tool to predict the behavior under many different conditions and can be used to guide the development process.
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