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System Simulation and Analysis of EPA 5-Cycle Fuel Economy for Powersplit Hybrid Electric Vehicles

Ford Motor Co.-Yan Meng, Mark Jennings, William Schwartz, Poyu Tsou
Published 2013-04-08 by SAE International in United States
To better reflect real world driving conditions, the EPA 5-Cycle Fuel Economy method encompasses high vehicle speeds, aggressive vehicle accelerations, climate control system use and cold temperature conditions in addition to the previously used standard City and Highway drive cycles in the estimation of vehicle fuel economy.A standard Powersplit Hybrid Electric Vehicle (HEV) system simulation environment has long been established and widely used within Ford to project fuel economy for the standard EPA City and Highway cycles. Direct modeling and simulation of the complete 5-Cycle fuel economy test set for HEV's presents significant new challenges especially with respect to modeling vehicle thermal management system and interactions with HEV features and system controls. It also requires a structured, systematic approach to validate the key elements of the system models and complete vehicle system simulations.This paper describes a methodology developed at Ford for system simulation and analysis of EPA 5-Cycle fuel economy for powersplit HEV's. Important newly developed elements of the vehicle system models are explained including the modeling of vehicle and engine controls and the procedures…
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A Numerical Methodology to Compute Temperatures of a Rotating Cardan Shaft

CD-adapco-Thomas Walker, Sachin Badarayani
Daimler AG-Heinrich Reister, Ernst Peter Weidmann
Published 2013-04-08 by SAE International in United States
In this paper a new numerical methodology to compute component temperatures of a rotating cardan shaft is described. In general temperatures of the cardan shaft are mainly dominated by radiation from the exhaust gas system and air temperatures in the transmission tunnel and underbody. While driving the cardan shaft is rotating. This yields a uniform temperature distribution of the circumference of the shaft. However most simulation approaches for heat protection are nowadays steady-state computations. In these simulations the rotation of the cardan shaft is not considered. In particular next to the exhaust gas system the distribution of the temperatures of the cardan shaft is not uniform but shows hot temperatures due to radiation at the side facing the exhaust gas system and lower temperatures at the other side. This paper describes a new computational approach that is averaging the radiative and convective heat fluxes circumferentially over bands of the cardan shaft. This yield a uniform distribution of relevant heat fluxes at the circumference of the rotating shaft. Based on these modified heat fluxes the temperature…
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Model-Based Methodology for Air Charge Estimation and Control in Turbocharged Engines

Hitachi Automotive Systems, Ltd.-Seiji Asano
Hitachi, Ltd.-Kunihiko Suzuki
Published 2013-04-08 by SAE International in United States
The purpose of this study is to develop model-based methodologies which employ thermo-fluid dynamic engine simulation and multiple-objective optimization schemes for engine control and calibration, and to validate the reliability of the method using a dynamometer test.In our technique, creating a total engine system model begins by first entirely capturing the characteristics of the components affecting the engine system's behavior, then using experimental data to strictly adjust the tuning parameters in physical models. Engine outputs over the full range of engine operation conditions as determined by design of experiment (DOE) are simulated, followed by fitting the provided dataset using a nonlinear response surface model (RSM) to express the causal relationship among engine operational parameters, environmental factors and engine output. The RSM is applied to an L-jetronic® air-intake system control logic for a turbocharged engine.Coupling the engine simulator with a multi-objective genetic algorithm, the optimal valve timings are investigated from the viewpoints of fuel consumption rate, emissions, and torque. The calibrations are made over all the operation points; the control map is implemented in the turbocharged…
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Development of Accelerated Reliability/Durability Testing Standardization as a Component of Trends in Development Accelerated Reliability Testing (ART/ADT)

Sohar Inc.-Lev Klyatis
Published 2013-04-08 by SAE International in United States
There are no standards that directly consider practical reliability testing technology (methods and equipment). This void needs to be filled. The SAE G-11 division has approved the development of six new standards to fill this void. This paper discusses these six standards: 1) Reliability Test-Glossary; 2) Reliability Testing-Strategy; 3) Reliability Testing-Procedures; 4) Reliability Testing-Equipment; 5) Reliability Testing-Statistical Criteria for Comparison of Reliability Testing Results and Field Results; 6) Reliability Testing-Collection, Calculation, and Statistical Analysis of Reliability Testing Data, Development Recommendations for Improvement of Test Subject Reliability, Durability, and Maintainability.These standards are planned as a basis for obtaining the information needed to accurately predict usage, reliability, durability, quality, supportability and maintainability throughout the life-cycle, as well as life-cycle costs in real-world conditions, and to reduce the possibility of conflicts, duplications, and incorrect interpretations either expressed or implied elsewhere in the literature.
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A Control Allocation Algorithm for Improving the Fail-Safe Performance of an Electric Vehicle Brake System

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Beihang Univ.-Chong Feng, Nenggen Ding, Yongling He, Guoyan Xu, Feng Gao
  • Journal Article
  • 2013-01-0187
Published 2013-04-08 by SAE International in United States
The ample electrical power supply makes brake-by-wire technology more suitable for application in electric vehicles than in conventional vehicles. The fail-safe performance of a brake-by-wire system is a key factor regarding its application on production vehicles. A new control allocation algorithm for improving the fail-safe performance of an electric vehicle brake system is proposed. The electric vehicle is equipped with a four-wheel independent brake-by-wire and steer-by-wire system. The main objective of the algorithm is to maintain the vehicle braking performance as close to the desired level as possible by reallocating the control inputs to the actuators in cases of partial or full failure of the brake-by-wire system. The control algorithm is developed using a two degrees of freedom vehicle model. A pseudo control vector is calculated by a sliding mode controller to minimize the difference between the desired and actual vehicle motions. A pseudo-inverse controller then allocates the control inputs according to the pseudo control vector and the failure mode which is assumed to have been determined by some diagnostic algorithms. The control algorithm is…
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Techniques for Contact Considerations in Fatigue Life Estimations of Automotive Structures

Chrysler Group LLC-Mingchao Guo, Kaizhi Quan, Suresh Bhosale, Congyue Wang, Sridhar Srikantan
Published 2013-04-08 by SAE International in United States
Contacts or interactions commonly exist between adjacent components in automotive structures, and most of the time they dominate stress status of the components. However, when the routine pseudo stress approach is employed in fatigue life estimations, simulating contacts present special challenges. This may result in coarse stress status and corresponding coarser fatigue life estimations at the contact locations. In this paper, concept, development and procedures of two techniques to consider contacts in fatigue life estimations of automotive structures are described in detail. One is still pseudo stress approach based, but employs additional 1-D connection elements to simulate contacts. The other is nonlinear stress approach based, but equivalent constantly repeating cyclic critical load cases are introduced and utilized. The contacts are simulated by interface setup provided in the software. The equivalent constantly repeating cyclic critical load cases are generated by the equal damage rule. Fatigue analyses using the routine pseudo stress approach, the approach with contacts simulated by 1-D connection elements and the approach with nonlinear stress approach have been conducted and compared for an example…
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Development of Long Haul Heavy Duty Vehicle Real World Fuel Economy Measurement Technique

Lubrizol Ltd-Wayne Moore, Mike Sutton, Kieron Donnelly
Published 2013-04-08 by SAE International in United States
For many years, governments have driven the improvement of fuel economy in transportation through tightening legislation. This effort has focused on passenger cars, but is increasingly concerned with heavy-duty vehicles (HDV). The combination of this regulatory focus with the ever present desire for low cost of ownership in commercial vehicles is giving increased pressure to deliver more fuel efficiency from the lubricants.In order to deliver improved fuel efficiency, suitable test methodology is needed to give repeatable discriminatory results that not only help in the advance of technology, but can also highlight the magnitude of the benefit expected in real-world applications. Typical on-road driving has significant variation in fuel consumption due to driver inconsistency, changes in rolling resistance and changeable ambient conditions. In order to avoid the effect of such variables, current practices, such as the EPA SmartWay™ methodologies typically utilize gravimetric measurement of removable fuel tanks or more recently the possibility of using Portable Emissions Measuring Systems (PEMS) over a set cycle.These methods do still have significant variability inherent within them, and, therefore an alternative…
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Impact of Supplemental Natural Gas on Engine Efficiency, Performance, and Emissions

The Pennsylvania State University-Claire Maxey, Vickey Kalaskar
University of Michigan-Dongil Kang, Andre Boehman
Published 2013-04-08 by SAE International in United States
In this study, the performance and emissions of a 4 cylinder 2.5L light-duty diesel engine with methane fumigation in the intake air manifold is studied to simulate a dual fuel conversion kit. Because the engine control unit is optimized to work with only the diesel injection into the cylinder, the addition of methane to the intake disrupts this optimization. The energy from the diesel fuel is replaced with that from the methane by holding the engine load and speed constant as methane is added to the intake air. The pilot injection is fixed and the main injection is varied in increments over 12 crank angle degrees at these conditions to determine the timing that reduces each of the emissions while maintaining combustion performance as measured by the brake thermal efficiency. It is shown that with higher substitution the unburned hydrocarbon (UHC) emissions can increase by up to twenty times. The NOx emissions decrease for all engine conditions, up to 53%. The thermal efficiency of the engine is highest with the most advanced injection timing for…
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Efficient Design Methodology of an All-Electric Vehicle Powertrain using Multi-Objective Genetic Optimization Algorithm

IFP Energies Novelles-Abdenour Abdelli, Fabrice Le Berr, Raouf Benlamine
Published 2013-04-08 by SAE International in United States
This paper presents a methodology to design the powertrain of an electrical vehicle (EV) in an optimal way. The electric vehicle optimal design is carried out using multiobjective genetic optimization algorithm. The developed methodology is based on the coupling of a genetic algorithm with powertrain component models. It allows determining the drive train components specifications for imposed vehicle performances, taking into account the dynamic model of the vehicle and all the components interactions. In this way, the components can be sized taking into account the whole system behavior in an optimal global design. The developed methodology is performed on the European driving cycle (NEDC) to estimate energy consumption gains but also powertrain mass reduction in comparison with a classical step-by-step methodology. This optimal procedure is notably important to increase electric vehicle range or reduce battery size and thus electric vehicle cost.
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Finite Element Method Based Fatigue Analysis of a Gray Cast Iron Component

Cummins Inc.-Yue Ma
Published 2013-04-08 by SAE International in United States
Good understanding and accurate prediction of component fatigue strength is crucial in the development of modern engine. In this paper a detail analysis was conducted on an engine component made of gray cast iron with finite element method to evaluate the fatigue strength. This component has notches that cause local stress concentration. It is well known that fatigue behavior of a notch is not uniquely defined by the local maximum stress but depends on other factors determined by notch geometry and local stress distribution. The component fatigue strength was underestimated by only considering the stresses on the notch surface for fatigue life prediction. The critical distance approach was adopted to predict the fatigue behavior of this component. Good agreements are observed between predicted life by the critical distance method and actual field data. It is recommended that the critical distance approach should be adopted in future component fatigue design to accurately predict notch sensitivity effects and determine non-propagating conditions.
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