Aerodynamic Simulation of a Parametrically Deformed Rotating Tire

<div class="section abstract"><div class="htmlview paragraph">The aerodynamics of a rotating tire can contribute up to a third of the overall aerodynamic force on the vehicle. The flow around a rotating tire is very complex and is often affected by smallest tire features. Accurate prediction of vehicle aerodynamics therefore requires modeling of tire rotation including all geometry details. Increased simulation accuracy is motivated by the needs emanating from stricter new regulations. For example, the upcoming Worldwide harmonized Light vehicles Test Procedures (WLTP) will place more emphasis on vehicle performance at higher speeds. The reason for this is to bring the certified vehicle characteristics closer to the real-world performance. In addition, WLTP will require reporting of CO<sub>2</sub> emissions for all vehicle derivatives, including all possible wheel and tire variants. Since the number of possible derivatives can run into the hundreds for most models, their evaluation in wind tunnels might not be practically possible. Therefore, simulations are very appealing alternative especially since their use is allowed by WLTP.</div><div class="htmlview paragraph">As a first step in order to meet these escalating demands, the current study uses a Lattice Boltzmann method (LBM) based computational fluid dynamics (CFD) solver using an immersed boundary method (IBM) based approach to simulate and validate a standalone rotating treaded tire. Preliminary wake plane prediction results are in good agreement with experimental wake plane measurements. Effect of tire loading on wake results is also discussed.</div></div>

<div class="section abstract"> <div class="htmlview paragraph">This document provides preliminary<sup><span class="xref">1</span></sup> safety-relevant guidance for in-vehicle fallback test driver training and for on-road testing of vehicles being operated by prototype conditional, high, and full (Levels 3 to 5) ADS, as defined by SAE J3016. It does not include guidance for evaluating the performance of post-production ADS-equipped vehicles. Moreover, this guidance only addresses testing of ADS-operated vehicles as overseen by in-vehicle fallback test drivers (IFTD).</div> <div class="htmlview paragraph">These guidelines do not address:</div> <ul class="list disc"> <li class="list-item"> <div class="htmlview paragraph">Remote driving, including remote fallback test driving of prototype ADS-operated test vehicles in driverless operation. (Note: The term “remote fallback test driver” is included as a defined term herein and is intended to be addressed in a future iteration of this document. However, at this time, too little is published or known about this type of testing to provide even preliminary guidance.)</div></li> <li class="list-item"> <div class="htmlview paragraph">Testing of driver support features (i.e., Levels 1 and 2), which rely on a human driver to perform part of the dynamic driving task (DDT) and to supervise the driving automation feature’s performance in real time. (Refer to SAE J3016.)</div></li> <li class="list-item"> <div class="htmlview paragraph">Closed-course testing.</div></li> <li class="list-item"> <div class="htmlview paragraph">Simulation testing (except for training purposes).</div></li> <li class="list-item"> <div class="htmlview paragraph">Component-level testing.</div></li></ul> <div class="htmlview paragraph">These guidelines also do not address prototype vehicle and IFTD performance data collection and retention. The collection of data invokes various legal and risk management considerations that users of this document should nevertheless bear in mind, such as:</div> <ul class="list disc"> <li class="list-item"> <div class="htmlview paragraph">Maintaining auditable procedures and documentation.</div></li> <li class="list-item"> <div class="htmlview paragraph">Adhering to applicable privacy laws and principles.</div></li> <li class="list-item"> <div class="htmlview paragraph">Ensuring adequate data collection and recording integrity to support post-crash forensic analysis.</div></li></ul></div>

<div class="htmlview paragraph">A novel gasoline <i>fuel optimizer</i> has been developed which is capable of modifying the combustion process in spark ignition engines. Fuel Optimizers are a new category of chemical compounds which are capable of altering the base combustion characteristics of the fuel itself, resulting in performance benefits far in excess of what is possible with traditional fuel additives.</div> <div class="htmlview paragraph">The fuel optimizer described in this paper, <b>X-ccelerator</b>™, alters the ignition and burning characteristics of the fuel-air mixture, resulting in enhanced combustion performance. Tests in combustion bombs as well as in an operating engine have shown that this additive can reduce combustion duration (both in terms of the ignition time and bulk burning time) and increase average peak combustion pressure. As a result, the indicated mean effective pressure is shown to be increased.</div> <div class="htmlview paragraph">One of the benefits of this enhanced combustion is improved vehicle performance and driveability characteristics. Decreased full- and part-throttle acceleration times have been demonstrated in a variety of modern vehicles. In controlled field evaluations, a majority of drivers have perceived general improvements to vehicle performance and driveability when using X-ccelerator. This fuel optimizer, which is ashless, is added to the base gasoline at a low concentration (200 parts per million), and is a highly cost-effective solution for improving vehicle and combustion performance. Extensive compatibility and no-harm testing has been conducted to ensure that no adverse interactions exist with the engine or any of its components.</div>

<div class="section abstract"><div class="htmlview paragraph">The customer perception of ride comfort with vehicle performance is the most important aspect in a vehicle design. The ride comfort and vehicle performance are influenced by driveline components i.e. propeller shaft phase angle, inclination angle and critical frequency of the driveline system. The optimization of the driveline system is essential to ensure the efficient and smooth power transfer. Propeller shaft is one of the critical components in the driveline to influence the vehicle performance.</div><div class="htmlview paragraph">Propeller shaft characteristics influenced by several factors like vehicle max torque, propeller shaft joint type, materials properties, UJ phase and inclination angle and shaft unbalance value. The optimization of the above parameter within the tolerance limit enables to meet the required performance standard. Various methodologies are available to optimize these parameters to enhance the vehicle performance and comfort leads to customer satisfactions. This study focuses on the analytical optimization of the propeller shaft’s universal joint (UJ) phase and inclination angle and validated at vehicle level.</div><div class="htmlview paragraph">An analytical model was employed to evaluate the velocity fluctuations across the full rotation of the propeller shaft by considering the different UJ phase angles (0<sup>°</sup> − 360<sup>°</sup>) and inclination angles (1<sup>°</sup> − 5<sup>°</sup>). It was observed from the study that optimization of these parameter improves the vibration performance and decreases the velocity fluctuations. The results shows that the well optimized propeller shaft will enhance smoothness in the driveline systems, reduction in NVH levels, vehicle performance and ride comfort. This study suggests the importance of the precise geometry alignment in driveline design and provide the further refinement methodology.</div></div>

<div class="htmlview paragraph"> </div> <div class="htmlview paragraph"> </div> <div class="htmlview paragraph">The quality of exhaust sound has become one of the important factors in the motorcycle market.</div> <div class="htmlview paragraph"> </div> <div class="htmlview paragraph">Therefore both an efficient sound quality evaluation method and technology to achieve ideal sound quality have become necessary.</div> <div class="htmlview paragraph"> </div> <div class="htmlview paragraph">Sound qualify evaluation has generally been performed by trial and error through repeated modification of exhaust silencer construction until desired quality was obtained.</div> <div class="htmlview paragraph"> </div> <div class="htmlview paragraph">But it usually took painstaking work and long hours.</div> <div class="htmlview paragraph"> </div> <div class="htmlview paragraph">In order to solve such problems, we established an objective auditory evaluation method.</div> <div class="htmlview paragraph"> </div> <div class="htmlview paragraph">We also applied Principal component analysis to analize the result of the “Semantic Differential Method (SD method)” so as to determine the affecting elements.</div> <div class="htmlview paragraph"> </div> <div class="htmlview paragraph">Through this analysis system, “powerful sound” caused by relatively higher content of the low frequency range and “crispy sound” caused by a cyclic sound pattern were determined to be desirable sounds for “American type” motorcycles.</div> <div class="htmlview paragraph"> </div> <div class="htmlview paragraph">We established a system for approximate frequency distribution characteristic estimation for simply constructed exhaust silencers by introducing a numerical computation method, called “Finite Element Method (FEM)” and “Boundary Element Method(BEM)” to estimate the sound when exhaust silencer component elements are modified.</div> <div class="htmlview paragraph"> </div>

<div class="htmlview paragraph">The business of hauling freight for profit is not easy. To be competitive, fleets must operate at low cost and provide excellent service. The truck manager is also responsible for safety on the highways and must comply with all legal requirements.</div> <div class="htmlview paragraph">An onboard computer can help a fleet obtain better fuel economy, increase productivity, reduce maintenance costs and improve safety practices. The payback period for a properly used management information onboard computer is about nine months.</div> <div class="htmlview paragraph">On the basis of improvement in safety alone, an onboard computer is an indispensable device. Today's society demands that all responsible businesses do everything reasonable to promote safety. An onboard computer represents a technology that is available now; it is a vital management tool for getting at the root of safety problems. Used properly, it can provide the control necessary to ensure safety and prevent damage to property.</div> <div class="htmlview paragraph">ALL FLEETS, WHETHER THEY are in the business of distributing groceries to stores, transporting crude petroleum to refineries, carrying hazardous material to factories, or dumping refuse at landfills, have one business in common -- the business of hauling freight for profit.</div> <div class="htmlview paragraph">In the process of conducting that business, the fleet management is surrounded with a multitude of issues such as high fuel costs, paperwork overload and maintenance expenses as well as compliance with Department of Transportation (DOT) requirements, safety enhancements, combating delays and improving productivity.</div> <div class="htmlview paragraph">Onboard computers can help management deal with these issues. Their utility can be more clearly understood by analyzing a trucking operation in four categories: vehicle performance, productivity, paperwork and safety.</div> <div class="htmlview paragraph">Some fleets also employ sophisticated truck-to-home office communication systems to improve their effectiveness. Onboard computers are well positioned to integrate with these technologies. They will continue to play an important role in the intelligent vehicle highway system of the future.</div>

<div class="section abstract"><div class="htmlview paragraph">Utilization of higher ethanol blends, 20% ethanol in gasoline (E20), as an alternate fuel can provide apparent benefits like higher octane number leading to improved anti-knocking properties, higher oxygen content resulting in complete combustion. Apart from technical benefits, use of ethanol blends offer certain widespread socioeconomic benefits including option of renewable source of energy, value addition to agriculture feedstock resulting in increase in farm income, creation of more jobs in rural sector and creating job at local levels. Use of higher blends of ethanol can reduce dependence on foreign crude leading to substantial savings in cost of petroleum import.</div><div class="htmlview paragraph">The impact of higher Gasoline-Ethanol blend (E20), on the fuel system components of gasoline vehicles must be known for assessment of whether the fuel system will be able to perform as intended for the complete design life of the system. Similarly, emission characteristics with use of such alternate fuels must also be evaluated to confirm its suitability before using it.</div><div class="htmlview paragraph">A comprehensive exercise was conducted for evaluation E20 fuel for its potential as an alternate transportation fuel. Laboratory immersion study on typical metals & non-metals used in the fuel system components of 4-wheelers & 2-wheelers was conducted for evaluation of change in properties, before and after immersion, like weight, volume, tensile strength, elongation, hardness and impact strengths of six elastomers and 4 plastics, and corrosion rate of eight metals. Statistical evaluation of the test results of properties, for elastomers and plastics, was conducted and majority of the results were found to be statistically significant.</div><div class="htmlview paragraph">Field trials were conducted on six 4-wheelers (old and new) through running-in, with both E20 and commercial gasoline, on roads representing various conditions and driving patterns including city, highway, expressway, hills/ghats, etc. Vehicle performance was evaluated through periodic mass emissions before, after and during vehicle running-in, evaporative emissions and component rating before & after mileage accumulation.</div><div class="htmlview paragraph">This paper presents the outcome of systematic evaluation of E20 fuel, in comparison with commercial gasoline, conducted through laboratory evaluation as well as field trails on 4-wheeler (old and new) vehicles.</div><div class="htmlview paragraph">A robust methodology was developed and followed for evaluation of alternate fuels in a holistic manner. The study revealed vital information on the performance of E20 fuel, in comparison to commercial gasoline, in terms of emissions, operating performance and material compatibility.</div></div>

<div class="htmlview paragraph">Several years of studies and experimentation commencing in 1977 at the Canadian National Research Council, have culminated in the construction of a regenerative power train of the parallel hybrid type.</div> <div class="htmlview paragraph">This paper presents the results of fuel economy tests conducted with the power train as installed in a North American City Bus.</div> <div class="htmlview paragraph">Testing was carried out using the Arterial and City Business District phases of the ADB cycles, together with a 5 stop per mile, 30 mph (48 km/h) cycle. Interestingly, with an unmodified bus, the 30 mph cycle was found to require 19% more fuel than the cycle average of the Arterial and City Business District Phases.</div> <div class="htmlview paragraph">In comparison with the same bus operating without the benefit of the regeneration package, a reduction in fuel consumption of some 17% was obtained.</div> <div class="htmlview paragraph">Even better comparative results are expected of the same system when used in typical city driving situations.</div> <div class="htmlview paragraph">A review of the energy balance in the current system, indicates that significant performance enhancements are feasible for a system of this type.</div> <div class="htmlview paragraph">In addition to the reduction of fuel consumed, a corresponding reduction in the exhaust gas emissions and smoke is achieved. The system also provides the possibility of reducing the required engine power rating to achieve a given vehicle performance.</div>

<div class="htmlview paragraph">In recent years, the fraction of air conditioning systems installed in American automobiles has increased to approximately 85%. Concurrently, efforts to improve fuel economy have resulted in smaller engines. The point has been reached in which load from a cycling fixed-displacement compressor can significantly affect vehicle drivability and performance. To remedy this problem, variable-capacity A/C systems have been developed with mechanically controlled compressor displacements.</div> <div class="htmlview paragraph">An alternative electronic approach to cooling capacity modulation is presented in this paper. The system utilizes a variable-speed brushless dc motor to drive a fixed-displacement compressor, thus achieving continuous control of cooling output independent of the engine drive belt. Compared to variable-displacement compressors, electrically driven A/C systems provide the following additional benefits: <ul class="list disc"> <li class="list-item"><div class="htmlview paragraph">Hermetic motor/compressor assembly (no shaft seal leakage)</div></li> <li class="list-item"><div class="htmlview paragraph">Smaller, less complex compressor</div></li> <li class="list-item"><div class="htmlview paragraph">Flexible packaging (no drive belt)</div></li> <li class="list-item"><div class="htmlview paragraph">Full cooling capacity at any engine speed</div></li> <li class="list-item"><div class="htmlview paragraph">Control of conditioned air temperature without reheat</div></li> </ul></div> <div class="htmlview paragraph">This paper deals with the development of a brushless dc drive system suitable for powering an automotive air conditioner. Two 5 hp motors were designed and built with maximum operating speeds of 6000 and 7000 rpm. These motors were then tested in a typical automotive air conditioning system over a range of operating conditions in order to determine their performance envelopes. The results are discussed, and conclusions are drawn as to the type of compressor and control strategy best suited for electric automotive A/C. Issues that are critical to the further development of electrically driven A/C systems are identified. An example simulation of annualized A/C system performance is also provided to quantify some of the benefits of cooling capacity modulation.</div>

<div class="section abstract"><div class="htmlview paragraph">In an automotive suspension, the shock absorber plays a significant role to enable the vehicle performances, especially in ride, handling and Noise-Vibration-Harshness (NVH). Understanding its physical characteristics is of great importance, as it has a main influence on the overall vehicle performance.</div><div class="htmlview paragraph">Within this research project simulation models for different passive monotube shock absorber systems have been created in a 1-D system simulation software. The simulation models are designed and parameterized physically.</div><div class="htmlview paragraph">To validate the simulation models measurements on different hydropulse-shaker with specially designed control signals to investigate the response during high frequency excitation, have been done. A detailed discussion of the several models and results of a simulation to measurement comparison is given. After detailed investigation the shock absorber simulation models are now adaptable to the multi body simulation.</div><div class="htmlview paragraph">As a result nearly equal experimental and simulated response of the different shocks was found. Some deviations are remaining during high frequency (>30Hz) operation of the damper. Dominant parameters to influence the damper response have been found. A sensitivity analysis shows the influences of these parameters. An analytical model to approach the shim stack stiffness was designed. For a validation detailed Finite-Element-Method (FEM) models of the shim stack have been developed and compared with load cases up to 100 bar hydraulic pressure. Additionally an FEM-model of the shock absorber and detailed modal analysis have been made to calculate and validate the natural frequencies of the shock. Limitations of this current study are the investigated monotube shock absorber systems, not including and including stroke-dependent-damping.</div><div class="htmlview paragraph">The presented novelty is the method of the configuration of the shock absorber simulation models only with geometric data. The shim stack models to calculate its stiffness instead of fatigue calculation are new as well. The new configuration approach increases the possibility to design automotive shock absorbers in advance of having a prototype. With the multi-body simulations of the chassis forecasts of the cars behaviour are possible at earlier stages during the development cycle. As OEM it is possible to simulate the behavior of the shock absorber in detailed car models.</div></div>

<div class="htmlview paragraph">The main goal of this paper is to present the methodology used at the Amazon Program, Ford South America Operations, to meet durability requirement for the Lower Control Arm Rear Bushing component which is being currently used by a McPherson Front Suspension.</div> <div class="htmlview paragraph">The durability target is defined based upon the expected functional useful vehicle life of 10 (ten) years and it reflects directly on the customer satisfaction level.</div> <div class="htmlview paragraph">In parallel, there are others requirements that need to be met as well such as Suspension Compliance, Transmissibility, Package, Manufacturability, Timing and Cost.</div> <div class="htmlview paragraph">Trade-off study has to be performed in order to weight each requirement and accomplish the best compromise among them.</div> <div class="htmlview paragraph">In order to meet durability requirement, an integrated approach is used considering the Road Load Data obtained from the first prototype and ending with a robust Component Rig-Test specification correlating component and vehicle performances.</div> <div class="htmlview paragraph">This paper intends to define this methodology having as a background the lessons learned the authors have acquired during the program development</div>

<div class="section abstract"><div class="htmlview paragraph">Tread belt separation and detachment is a common failure mode of radial tires. The accident reconstructionist is frequently asked to evaluate the effect of tread belt separation and detachment relative to the occurrence of an accident. Publications have previously been directed toward defining the effects of rapid tire deflation on vehicle drag and handling. However, little has been written about the singular effect of the loss of the tire tread belt relative to vehicle handling. The loss of a tread belt from a tire may be followed by rapid deflation. The combined separation and detachment event may have similar effects on vehicle handling as a rapid deflation event.</div><div class="htmlview paragraph">To evaluate the effect of the loss of a tread belt without tire deflation, the authors tested tires prepared so that the tread belts could be intentionally separated while driving at speeds between 50 and 75 miles per hour. The initial phase of the test was conducted at the Transportation Research Center (TRC) in East Liberty, Ohio on the Vehicle Dynamics Area track. The track contains a <span class="xref">figure 8</span> with banked turns. The long straightaway in the center traverses a rectangular, level skid pad. The test vehicle was a 1993 Ford Taurus four door sedan. The tires were size P205/65R15. Twelve tires were tested on the TRC track. Three were tested at each wheel position. Nine tread belt detachments were produced on a straightaway. Three detachments were in curves or during a driver induced steering maneuver. The tread detachments occurred at speeds between 50 and 75 miles per hour. All tread belts separated in one continuous piece, with two or three small fragments in some cases.</div><div class="htmlview paragraph">All of the authors were involved as test drivers and passengers to introduce a range of driver skills and responses. The vehicle speed, forward and lateral acceleration rates, and the driver induced steering torque was measured and recorded. The tests were all videotaped with an in-vehicle camera. All but one of the tests was videotaped from a chase vehicle. The tests that occurred on the straightaway were also videotaped from a stationary camera.</div><div class="htmlview paragraph">Separate tests were conducted to obtain comparative drag and lateral steering effects for intact and inflated tires, and for deflated tires with the tread belt in place. The sequence was repeated for tires with the tread belt detached. These tests were conducted in accordance with the test protocol defined in SAE970954 “Drag and Steering Effects of Under Inflated and Deflated Tires”[<span class="xref">1</span>].</div></div>

<div class="section abstract"><div class="htmlview paragraph">Spray formation and break-up are crucial phenomena for mixture formation inside diesel engines, both for combustion control and pollutant formation. Since the emission restrictions have become more and more severe in the last years, many studies have been conducted in order to improve diesel injection. Numerical simulations have proven to be reliable in producing results in a faster and cheaper way than experimental measures. The recent great progresses in computer science, then, have allowed to reach great accuracy in the simulations.</div><div class="htmlview paragraph">In this work, a novel methodology based on Boltzmanns Kinetic Theory is applied to diesel injection. Lattice Boltzmann BGK (LBGK) provides and alternative method for solving fluid-dynamic problems and allows even superior accuracy as compared to conventional CFD.</div><div class="htmlview paragraph">The multiphase approach used in this paper to study spray formation and primary is based on the works by Shan and Chen and their successive modifications.</div><div class="htmlview paragraph">The results are compared to those predicted by means of the most accredited models in literature.</div></div>

<div class="htmlview paragraph">Although computer models for vehicle and sub-system performance simulations have been developed and used extensively in the past several decades, there is currently a need to enhance the overall availability of these types of tools. Increasing demands on vehicle performance targets have intensified the need to obtain rapid feedback on the effects of vehicle modifications throughout the entire development cycle.</div> <div class="htmlview paragraph">At the same time, evolution of the PC and development of Web-based applications have contributed to the availability, accessibility, and user-friendliness of sophisticated computer analysis.</div> <div class="htmlview paragraph">Web engineering is an ideal approach in supporting globalization and is a cost-effective design-analysis integration business strategy. There is little doubt that this new approach will have positive impacts on product cost, quality, and development cycle time.</div> <div class="htmlview paragraph">This paper will show how Microsoft Excel and the Web can be powerful and effective tools in the development process. To demonstrate the technique, a vehicle wide-open-throttle acceleration performance simulation example will be presented.</div> <div class="htmlview paragraph">Basic equations and assumptions will be reviewed, followed by a discussion on the consideration of several special conditions. Applicable programming techniques will be presented. An example of Web-based execution is provided.</div>

<div class="htmlview paragraph">The Indian motorcycle and scooter market is faced with the combined challenge of exhaust emissions control from the environmental perspective and fuel economy demands from the consumer. Indian motorcycles are unique in their strong focus on reduced fuel consumption and this has resulted in the development of engines with quite different combustion characteristics in comparison to their European and ASEAN counterparts.</div> <div class="htmlview paragraph">Aprilia, Peugeot and Piaggio have recently released new scooter models utilizing air assist direct injection on their small 2-stroke engines to meet the ever increasing pressure on exhaust emissions, fuel economy and performance. These new scooter models are achieving good acceptance with the customer due to their combination of superior performance and improved fuel economy.</div> <div class="htmlview paragraph">Recent investigations by Orbital on Indian scooters and motorcycles show that the air assist direct injection system can be applied to Indian 2-stroke engines to meet the Indian 2005 emissions requirements without a catalyst and simultaneously provide a 30-35% fuel economy improvement on the Indian Driving Cycle (IDC). These results are superior to today's good 4-stroke fuel economy motorcycles and advance the 2-stroke motorcycle to best in class fuel economy status.</div> <div class="htmlview paragraph">Investigations have also been conducted by Orbital regarding the application of this air assist direct injection system onto Indian 4-stroke motorcycles. This study has shown good results with a fuel economy improvement of 12-15 % over the current levels. This is a unique achievement and is potentially more cost effective than the fitment of port injection systems when considering the fuel cost saving available with air assist direct injection.</div> <div class="htmlview paragraph">System descriptions, engine and vehicle performance, fuel economy and emissions capability test data are discussed in the following pages.</div>