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Restriction Model Independent Method for Non-Isentropic Outflow Valve Boundary Problem Resolution

Gipsa Lab-Emmanuel Witrant, Luc Dugard
RENAULT SAS-Felipe Castillo
Published 2012-04-16 by SAE International in United States
To meet the new engine regulations, increasingly sophisticated engine alternative combustion modes have been developed in order to achieve simultaneously the emission regulations and the required engine drivability. However, these new approaches require more complex, reliable and precise control systems and technologies. The 0-D model based control systems have proved to be successful in many applications, but as the complexity of the engines increases, their limitations start to affect the engine control performance. One of the 0-D modeling limitations is their inability to model mass transport time. 1-D modeling allows some of the 0-D models limitations to be overcome, which is the motivation of this work. In this paper, two quasi-steady outflow boundary models are developed: one is based on the isentropic contraction and the other on a momentum conservation approach. Both are compared with computational fluid dynamics (CFD) 3-D simulations. Then, an innovative method for solving the outflow boundary problem taking into account the entropy correction at the boundary for a 1-D unsteady gas flow modeling is presented. Its formulation allows more predictive quasi-steady…
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Methodology for Assessment of Alternative Hybrid Electric Vehicle Powertrain System Architectures

SAE International Journal of Alternative Powertrains

Ford Motor Co.-Alexander T. Zaremba, Ciro Soto, Mark Jennings
  • Journal Article
  • 2012-01-1010
Published 2012-04-16 by SAE International in United States
Hybrid electric vehicle (HEV) systems offer significant improvements in vehicle fuel economy and reductions in vehicle generated greenhouse gas emissions. The widely accepted power-split HEV system configuration couples together an internal combustion engine with two electric machines (a motor and a generator) through a planetary gear set. This paper describes a methodology for analysis and optimization of alternative HEV power-split configurations defined by alternative connections between power sources and transaxle. The alternative configurations are identified by a matrix of kinematic equations for connected power sources. Based on the universal kinematic matrix, a generic method for automatically formulating dynamic models is developed. Screening and optimization of alternative configurations involves verification of a set of design requirements which reflect: vehicle continuous operation, e.g. grade test; and vehicle dynamic operation such as acceleration and drivability. Only the former are consider in this paper. The method automatically defines a design parameter space for each configuration which eventually would allow configuration evaluation and optimization, e.g. sizing of power sources or optimization of transaxle gear ratios.
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A Critique of Critical Speed Yaw Mark Research

Delta-V Experts-Shane Richardson, Tia Orton, Nikola Josevski, Wei Pei (Tandy) Pok, Andreas Sandvik, Chris Jones
Published 2012-04-16 by SAE International in United States
Critical speed yaw marks are commonly used in collision reconstruction to estimate vehicle speed. Research and laboratory testing have demonstrated that critical speed calculations can be used to accurately estimate vehicle speed. Thus, the principles supporting critical speed yaw analysis are fundamentally and theoretically valid and are not being challenged in this study. However, there are observed and documented limitations with respect to the appropriate application and execution of critical speed yaw analysis. This paper reviews the published research to-date and identifies limitations of critical speed yaw analysis. Examples of collision scenes are provided which quantify the inaccuracies associated with the misuse of critical speed yaw calculations. Areas for further research are identified and detailed.
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Control Allocation based Optimal Torque Vectoring for 4WD Electric Vehicle

Seoul National Univ.-Juyong Kang, Yi kyongsu, Hyundong Heo
Published 2012-04-16 by SAE International in United States
This paper describes an optimal torque vectoring strategy for 4WD electric vehicles (EV) in order to improve vehicle maneuverability, lateral stability and at the same time prevent vehicle rollover. The 4WD EV is driven using an in-line motor at a front driving shaft and in-wheel motors at rear wheels. Many previous studies have been conducted to determine a desired traction force and a yaw moment input for human driver's intention or vehicle stability control. The driving control algorithm consists of three parts: a supervisory controller that determines the control mode, admissible control region, and desired dynamics, such as the desired speed and yaw rate, an upper-level controller that computes the traction force input and yaw moment input to track the desired dynamics and an optimal torque vectoring algorithm that determines actuator commands, such as the front in-line motor, rear in-wheel motors and independent brake modules. The optimal torque vectoring algorithm is developed to map the desired traction force and the yaw moment input to the actuators, taking into account the actuator constraints. Also, a wheel…
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Development of Closed-Loop Robust Control System for Diesel Engines - Combustion Monitoring by Crank Angular Velocity Analysis and its Applications -

Toyota Motor Corporation-Yukitoshi Aoyama, Ryo Hasegawa, Tomomi Yamada, Takekazu Itoh, Terutoshi Tomoda, Yuichi Shimasaki
Published 2012-04-16 by SAE International in United States
Closed-loop robust control system that can monitor combustion state and control it into optimal state using crank angular velocity analysis was established. The system can be constructed without any change of the current hardware. It can avoid engine stall, deterioration of drivability and white smoke emission by misfire after filling low cetane fuels. This study was attempted to grasp the frequency characteristics of crank angular velocity both normal combustion and misfire with FFT (Fast Fourier Transform) and Wavelet Transform. FFT used for frequency analysis is generic method to acquire the frequency characteristics of steady oscillation, however is unsuitable for acquiring the frequency characteristics of transient oscillation. Therefore authors adopted Wavelet Transform and succeeded in grasping the phenomenon in misfiring in time sequential. With this knowledge, this study was attempted to determine the combustion instability by extracting frequency element of the 0.5 order of engine speed that is the characteristic frequency element in misfiring from pulse signal of the crank angle sensor with digital filters. With this method, misfire and combustion instability with white smoke caused…
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Numerical Optimization of a Light-Duty Compression Ignition Engine Fuelled With Low-Octane Gasoline

Bishwadipa Das Adhikary
Argonne National Laboratory-Stephen Ciatti
Published 2012-04-16 by SAE International in United States
In automotive industry it has been a challenge to retain diesel-like thermal efficiency while maintaining low emissions. Numerous studies have shown significant progress in achieving low emissions through the introduction of common-rail injection systems, multiple injections and exhaust gas recirculation and by using a high octane number fuel, like gasoline, to achieve adequate premixing. On the other hand, low temperature combustion strategies, like HCCI and PCCI, have also shown promising results in terms of reducing both NOx and soot emissions simultaneously. With the increasing capacity of computers, multi-dimensional CFD engine modeling enables a reasonably good prediction of combustion characteristics and pollutant emissions, which is the motivation behind the present research. The current research effort presents an optimization study of light-duty compression ignition engine performance, while meeting the emission regulation targets. A numerical optimization study was carried out on a light-duty, single-cylinder, compression ignition engine, fueled with a PRF87 gasoline surrogate, at a full load operating condition. The simulations were performed using a Non-dominated Sorting Genetic Algorithm II (NSGAII) code coupled to a multi-dimensional CFD code,…
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Seat Comfort as a Function of Occupant Characteristics and Pressure Measurements at the Occupant-Seat Interface

University of Michigan-Dearborn-Anjan Vincent, Vivek D. Bhise, Pankaj Mallick
Published 2012-04-16 by SAE International in United States
Seat comfort is a highly subjective attribute and depends on a wide range of factors, but the successful prediction of seat comfort from a group of relevant variables can hold the promise of eliminating the need for time-consuming subjective evaluations during the early stages of seat cushion selection and development. This research presents the subjective seat comfort data of a group of 30 participants using a controlled range of seat foam samples, and attempts to correlate this attribute with a) the anthropometric and demographic characteristics of the participants, b) the objective pressure distribution at the body-seat interface and c) properties of the various foam samples that were used for the test. It was found that: a) the “Indentation Load Deflection” characteristic (or ILD) of the foam was a very significant factor (within the scope of this experiment) contributing to subjective comfort, b) the age of the participants had an effect on comfort ratings as well as the seating pressure variables and it also interacted with seat ILD in influencing the seat comfort ratings, c) the…
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High Efficiency and Clean Diesel Combustion Concept using Double Premixed Combustion: D-SPIA

Toyota Industries Corporation-Hiroshi Kuzuyama, Masahiro Machida, Tsutomu Kawae, Takeshi Tanaka, Hideki Aoki, Yoshio Sugiyama, Tsutomu Umehara
Published 2012-04-16 by SAE International in United States
A new concept, Diesel Staggered Premixed Ignition with Accelerated oxidation (D-SPIA) was developed for lower exhaust emissions and carbon dioxide (CO₂) and this is based on divided fuel injection before top dead center (TDC). D-SPIA is a result of investigating various diesel combustion methods. Although the D-SPIA is a type of Premixed Charge Compression Ignition (PCCI), it has a distinct feature of double premixed combustion by optimum injection quantities and staggered timing, which can achieve an ideal heat release rate for low pollutant emissions and fuel consumption.Based on this concept, second injection timing and the proportion of the second fuel injection quantity play significant roles to reduce smoke, and hydrocarbon (HC) and carbon monoxide (CO) emissions. The second injection timing has a close relation to the premixed time of the second fuel injection and smoke level. The in-cylinder temperature at the second injection timing, which is related to the premixed time of the second fuel injection, is affected by the low-temperature heat release (LTHR) or the high-temperature heat release (HTHR) of the first fuel injection.…
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Efficient Random Vibration Analysis Using Markov Chain Monte Carlo Simulation

SAE International Journal of Materials and Manufacturing

Univ. of Toledo-Mahdi Norouzi, Efstratios Nikolaidis
  • Journal Article
  • 2012-01-0067
Published 2012-04-16 by SAE International in United States
Reliability assessment of dynamic systems with low failure probability can be very expensive. This paper presents and demonstrates a method that uses the Metropolis-Hastings algorithm to sample from an optimal probability density function (PDF) of the random variables. This function is the true PDF truncated over the failure region. For a system subjected to time varying excitation, Shinozuka's method is employed to generate time histories of the excitation. Random values of the frequencies and the phase angles of the excitation are drawn from the optimal PDF. It is shown that running the subset simulation by the proposed approach, which uses Shinozuka's method, is more efficient than the original subset simulation. The main reasons are that the approach involves only 10 to 20 random variables, and it takes advantage of the symmetry of the expression of the displacement as a function of the inputs. The paper demonstrates the method on two examples.
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Development of a New Multi-link Rear Suspension

SAE International Journal of Passenger Cars - Mechanical Systems

Nissan Motor Company Ltd.-Reo Koide, Yoshihiro Kawabe, Keiichi Nakajima, Kiriyama Kazuhiro
  • Journal Article
  • 2012-01-0978
Published 2012-04-16 by SAE International in United States
The requirements of suspension systems have become increasingly complex in recent years due to the expansion of global markets and diversification of the conditions under which vehicles are used in different parts of the world. It is also becoming increasingly important to ensure that vehicles offer the secure handling stability which are expected by drivers, but can also provide an adequate level of ride comfort when driving on a wide diversity of road surfaces in all parts of the world. From an environmental viewpoint, it is also essential to achieve weight reductions for better fuel economy.To meet these wide-ranging requirements, we have developed a new multi-link rear suspension that has a simple link configuration and a lower link that features a connecting bushing mechanism developed by Nissan. This innovative new connecting bushing mechanism not only helps to provide better handling stability by ensuring high stiffness and an adequate level of compliance steer, but also helps to improve the ride comfort by suitably controlling the behavior of tires when they encounter irregularities in the road surface,…
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