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Minimizing Power Consumption of Fully Active Vehicle Suspension System Using Combined Multi-Objective Particle Swarm Optimization

Helwan University-Ahmed Elsawaf, H. Metered, A. Abdelhamid
Published 2019-07-16 by SAE International in United States
This paper introduces an optimum design for a feedback controller of a fully active vehicle suspension system using the combined multi-objective particle swarm optimization (CMOPSO) in order to minimize the actuator power consumption while enhancing the ride comfort. The proposed CMOPSO algorithm aims to minimize both the vertical body acceleration and the actuator power consumption by searching about the optimum feedback controller gains. A mathematical model and the equations of motion of the quarter-car active suspension system are considered and simulated using Matlab/Simulink software. The proposed active suspension is compared with both active suspension system controlled using the linear quadratic regulator (LQR) and the passive suspension systems. Suspension performance is evaluated in time and frequency domains to verify the success of the proposed control technique. The simulated results reveal that the proposed controller using CMOPSO grants a significant enhancement of ride comfort and road holding, and reduction of actuator power consumption.
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Optimization Approach to Passive Engine Mounting System for Reducing Automotive Vibrations

K. N. Toosi University of Technology-Reza Abedi, Amir H. Shamekhia
Shahid Beheshti University-Abbas Rahi
Published 2019-07-08 by SAE International in United States
Improvised noise, vibration, and harshness (NVH) performance of vehicle implies better comfort for passengers. Apart from road inputs, engine vibration is one of the major contributors to interior vibrations in automotive. The aim of this paper is to optimize specifications and locations of engine mounts to reduce vehicle vibration without affecting engine performance and to provide better ride comfort. This paper also includes the challenges involved in the analysis of engine vibration on critical conditions such as movement on the road surface or braking action. Therefore, a fully numerical simulation expands to a four-cylinder engine by considering piston side force. In this model, the mass distribution in the connecting rod and crankshaft, outside of the center pin, and friction between the cylinder and piston have been considered. Furthermore, simulation analysis is implemented for an engine in vehicle movement with constant speed on the road class B roughness and braking conditions. Engine location, the angle of placement, and dynamic characteristics of mounts are the important parameters to reduce vibrations transferred to the vehicle frame. The optimization…
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Determination of a Tyre’s Rolling Resistance Using Parallel Rheological Framework

University of Birmingham-Hamad Sarhan Aldhufairi, Oluremi Olatunbosun, Khamis Essa
Published 2019-06-20 by SAE International in United States
Nowadays, rolling resistance sits at the core of tyre development goals because of its considerable effect on the car’s fuel economy. In contrast to the experimental method, the finite element (FE) method offers an inexpensive and efficient estimation technique. However, the FE technique is yet to be a fully developed product particularly for rolling-resistance estimation. An assessment is conducted to study the role of material viscoelasticity representation in FE, in linear and non-linear forms, through the use of Prony series and parallel rheological framework (PRF) models, respectively, on the tyre’s rolling-resistance calculation and its accuracy. A unique approach was introduced to estimate the rolling resistance according to the tyre’s hysteresis energy coefficient. The non-linear PRF choice resulted in rolling-resistance calculations that reasonably match that of the experimental work and the literature for various vertical load and inflation cases, whereas the Prony series option was found irresponsive to the tyre’s deformation in which it gave unreliable and infinitesimal outputs.
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Improved Kmeans Algorithm for Detection in Traffic Scenarios

Tongji University-Xiangyong Liu, Guang Chen
Published 2019-06-17 by SAE International in United States
In the Kmeans cluster segmentation used in traffic scenes, there are often zone optimization and over-segmentation problems caused by the algorithm randomly assigning the initial cluster center. In order to improve the target extraction effect in traffic road scenes, this article proposes an improved Kmeans (IM-Kmeans) method.Firstly, search for the histogram peaks of the whole pixels based on hue, saturation, value (HSV) image, and find the initial cluster centers’ positions and number. Secondly, the noise points which are far away from the center pixel are removed, and then the pixels are classified into the nearest cluster center according to its value. Finally, after the clustering model reaches convergence, the area-clustering method is used for another classification to solve the over-segmentation problem.The simulation and experimental comparisons show that the IM-Kmeans algorithm has higher clustering accuracy than the traditional Kmeans algorithm.
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PreHaz: A Premortem Functional Safety Hazard Assessment Technique for Autonomous Vehicles

DISTek Integration-Daniel Aceituna
Published 2019-06-14 by SAE International in United States
When performing functional safety hazard assessments, the challenge is anticipating all the things that can go wrong during a system’s operation. Hazard assessment tends to be performed in an ad hoc (where do I begin assessing?) and open-ended (when do I stop assessing?) manner. It is difficult for humans to factor in all the variables that affect a system’s nominal interaction with the environment and then predict all the combinational behaviors (good or bad) resulting from those variables. Quite often, after the system is built, a hazardous situation will occur that no one expected, and perhaps even assumed improbable. At those times engineers may employ a postmortem and realize that, with enough forethought, the hazard could have been assessed and anticipated. In contrast to the postmortem, there is the premortem, which tries to assess what can go wrong, before it actually occurs. This paper introduces a technique based on the premortem that can be applied to the development of a product and, in particular, to the assessment of hazardous situations that could arise from the…
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Developing a Theory for Active Grille Shutter Aerodynamics—Part 1: Base Theory

Porsche AG-Thomas Wolf
Published 2019-06-07 by SAE International in United States
The aim is to develop a theory to describe the aerodynamic behavior of active grille shutters (AGS). The theory correlates the cooling air mass flow and drag of a vehicle with the angle and number of air flaps on the AGS. The relatively simple mathematical formulation of this theory provides an insight into the aerodynamic behavior and characteristic curve shape of AGS. It illustrates how the number of air flaps changes and influences the shape of the AGS characteristic curve. The theory is validated by experiments using wind tunnel measurements on real vehicles with AGS. The comparisons show good agreement between theory and experiment.
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Multi-Zone Dynamic Modeling of Thermal Behavior in Vehicle’s Cabin for Comfort and Energy Saving

Malek-Ashtar University of Technology-Fatemeh Ghadiri Modares, Reza Soltani
Published 2019-05-31 by SAE International in United States
In the present work, the mathematical modeling of heat transfer in a vehicle’s cabin is investigated. The vehicle’s cabin temperature is one of the most important factors in accidents. Thus, it is not surprising that HVAC has a direct impact on the performance of occupants inside the cabin and especially the driver. Therefore, it is important to create a good thermal environment to provide thermal comfort for the driver and passengers. The focus of the current work is on mathematical modeling and analysis of the comfort conditions of the cabin. It is already hypothesized in this study that the gas behavior is ideal and the air properties inside the cabin depend on HVAC module air flow and controlled/uncontrolled leakage; the air in the cabin is appropriately mixed and no mechanical work is generated within the control volume. Effective thermal loads on the vehicle’s cabin are considered, including radiation, ventilation, ambient air, metabolic state, engine, exhaust, infiltration, and HVAC system, and changes in the temperature and relative humidity of the air of the cabin over time…
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An Optimal Gear Shifting Strategy for Minimizing Fuel Consumption Based on Engine Optimum Operation Line

Babol Noshirvani University of Technology-Kamyar Nikzadfar, Nima Bakhshinezhad, S. Ali MirMohammadSadeghi, Hossein Taheri Ledari, Alireza Fathi
Published 2019-05-21 by SAE International in United States
The increasing numbers of vehicles with limited fossil fuel resources, on the one hand, and the growing level of stringent regulations on exhaust emissions, on the other hand, have galvanized automotive industries and researchers into developing solutions for more efficient vehicles. Notwithstanding the recent developments in powertrain technologies, driving behavior is still an important attribute in lowering fuel consumption. Gear shifting strategy is a staple aspect of driving behavior that affects fuel consumption and engine emissions to a large extent in both manual and automated transmission systems. According to the definition of Optimum Operating Line (OOL), this article intends to illustrate that the closer the engine operating points to the OOL, the more efficient the driving. An optimal gear-shifting strategy is presented to minimize fuel consumption and number of gear shifts while maximizing drivability in the new European driving cycle (NEDC). In order to limit the engine operating region close to the OOL, a multi-objective grid search method is used to design the two square-root-like curves (two shifting thresholds), on both sides of the OOL,…
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Knock and Pre-Ignition in Spark-Ignition Engine Fuelled by Different Blends of Jojoba Bio-Gasoline with Kerosene

Helwan University-M.S. Radwan, Youssef A. Attai, Y.I. Hassan
Published 2019-05-17 by SAE International in United States
In the present article, the knock tendency and pre-ignition resistance (PIR) were determined experimentally for different blends of kerosene and jojoba bio-gasoline. The effects of varying equivalence ratios, rotational speed, inlet air temperature and pressure, and ignition timing on knock tendency and PIR were investigated. The influence of compression ratio on PIR was also studied. Jojoba bio-gasoline was synthesized using transesterification method through performing a chemical reaction between well-stirred jojoba raw oil and alcohol. Experiments were carried out on a Ricardo E6/MS variable compression ratio spark-ignition (SI) engine fuelled by jojoba bio-gasoline/kerosene blends of volumetric percentages of 0%, 5%, 10%, 15%, and 20% jojoba bio-gasoline. The onset of pre-ignition and knock were detected by observing the pressure oscillations using a piezoelectric pressure transducer, a synchronizing magnetic sensor, and a degree-marking probe. The results showed that increasing the percentage of bio-gasoline in the blends with kerosene leads to a significant increase in PIR and a remarkable decrease in the knock tendency. This will lead to the design of a more efficient engine by increasing its compression…
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Nonlinear Modelling and Parametric Study of a Sealed Tuned Liquid Column Damper for Vibration Mitigation

Helwan University Faculty of Engineering-Mohamed Fahmy Younes
Published 2019-05-16 by SAE International in United States
The main intention of the present study is to reduce unwanted vibrations of mechanical systems through a sealed tuned liquid column damper (STLCD). A nonlinear mathematical model including nonlinear hydrodynamic damping and air stiffness of the STLCD is considered to study the dynamic behaviour of a structure-STLCD system. A parametric study to investigate the effect of the main parameters of the STLCD such as length ratio and mass ratio on the dynamic behaviour of the main system is presented. The air volume at rest is considered as an additional design parameter. The results obtained showed that the efficiency and the range of application of the STLCD to control the system’s resonance vibration are more than that of the traditional one. In addition, it can be noticed that the gain in vibration mitigation from the STLCD with increase in mass ratio and length ratio higher than 7% and 0.8, respectively, is generally modest. These results enhance the actual implementation of the STLCD for small horizontal space applications. Equations for the optimum value of the initial air…
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