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Training / Education
2014-10-16
Developing vehicles that achieve optimum fuel economy and acceleration performance is critical to the success of any automotive company, yet many practicing engineers have not received formal training on the broad range of factors which influence vehicle performance. This seminar provides this fundamental understanding through the development of mathematical models that describe the relevant physics and through the hands-on application of automotive test equipment. Attendees will also be introduced to software used to predict vehicle performance. The course begins with a discussion of the road load forces that act on the automobile (aerodynamic, rolling resistance, and gravitational) followed by a review of pertinent engine characteristics. This background information is then used to show how appropriate gear ratios for a vehicle transmission are selected and to develop models for predicting acceleration performance and fuel economy. The models form the basis for the computer software used to predict vehicle performance.
Video
2014-04-14
This video summarizes Chapter 5 of the book, “Theory and Applications of Aerodynamics for Ground Vehicles”, by Dr. T. Yomi Obidi, published by SAE International. Concepts demonstrated include the effect of various vehicle components on performance and tire rotation, tire size, and effect on permformance.
Event
2014-04-10
Focusing on tire and terrain mechanics modeling for load simulations, tire model development, parameters identification, and sensitivity analyses, tire test development, road profile characterization, effective road profile development, and interactions between tire, suspension/steering/brake systems, and different terrains, spindle loads/travel variation characteristics from proving ground test on deterministic and rough roads, terramechanics, tire noise, rolling resistance and correlation studies.
Event
2014-04-09
Focusing on multibody system modeling and simulation results, rigid and flexible body modeling, mount loads predictions for vehicle body, frame/sub-frame, leaf-spring, exhaust system, driveline, and powertrain, the comparison of modeling techniques between vehicle dynamics simulation and durability loads simulation, optimal development process considering vehicle dynamics and durability loads, data processing and analysis techniques, loads sensitivity analyses for various model parameters, DOE and optimal design techniques for loads minimization, prediction of manufacturing tolerance effects on loads, robust design methods, driver modeling, and FE-based system modeling.
Event
2014-04-09
Focusing on analysis and enhancement of vehicle dynamics performance including handling / braking / traction characteristics, operational robustness and active stability under the influence of loading, tire forces and other variants; development and applications of intelligent tire technology; modeling, simulation, testing and optimization; correlation of analyses, simulations, objective measurements and subjective judgments of vehicle dynamics characteristics; chassis control development and control system cooperation for enhancing overall vehicle system dynamics and safety characteristics and robustness taking into considerations of load variations and other uncertainties; impact of system hybridization and electrification on vehicle dynamics and controls.
Event
2014-04-08
Focusing on studies of driver behavior modeling, driving simulator techniques, vehicle ride comfort evaluation and enhancement, test/simulation correlation analysis, vehicle elastomeric component modeling (i.e. bushings, rubber mounts, springs, dampers, seat cushions), passive, semi-active and active suspension systems, suspension seat analysis and modeling techniques, the effect and control of beaming, shaking, impact harshness, brake judder and any other phenomena affecting ride comfort of driver, passengers, goods, etc.
Event
2014-04-08
Focusing on new theory, formulation and modeling of amplitude-, frequency- and temperature-dependent nonlinear components/systems such as rubber and hydraulic mounts or bushings, shock absorbers, and any joint friction/damping; dynamic characterization through lab and field testing; Linearization methodology; Model validation, application, and sensitivity analysis in vehicle system/subsystem simulations; Nonlinear system identification, modeling, and application in testing accuracy improvement, etc.
Technical Paper
2014-04-01
Ming Chen, Dong Wang, Huiqiang Lee, Chao Jiang, Jun Xin
This paper describes the application of CAE tools in the design optimization of a DCT and driveline system of a passenger vehicle, with emphasis on NVH performance. The multi-body dynamics simulation tools are employed for driveline system analysis. The MBD model consists of the engine, transmission, clutch, drive shafts, tires and vehicle. The wheel slip effects are considered in the calculation of shuffle frequencies. In the analysis of gear whine, the transmission housing, gears and shafts are modeled by detailed 3-D finite element models, so that the mesh stiffness of the gears and the housing support stiffness are described more accurately. The calculated velocity spectra of the housing are presented. The prediction of gear rattle in the transmission is carried out. The loose gear acceleration index and the averaged impact power of free gears are calculated to assess the rattle generation potential and the level of rattle severity. The influence of the clutch spring rate and the gear backlash on rattle behavior is investigated.
Technical Paper
2014-04-01
Shugang Jiang, Michael H. Smith
Abstract Variable compression ratio and variable displacement technologies are adopted in internal combustion engines because these features provide further degrees of freedom to optimize engine performance for various operating conditions. This paper focuses on a multiple-link mechanism that realizes variable compression ratio and displacement by varying the piston motion, specifically the Top Dead Center (TDC) and Bottom Dead Center (BDC) positions relative to the crankshaft. It is determined that a major requirement for the design of this mechanism is when the control action changes monotonically over its whole range, the compression ratio and the displacement should change in opposite directions monotonically. This paper presents an approach on how to achieve multiple-link mechanism geometric designs that fulfill this requirement. First, a necessary and sufficient condition, and a stronger sufficient condition are obtained on how the TDC and BDC positions should change with respect to the control action to fulfill the design requirement.
Technical Paper
2014-04-01
Benjamin Rodriguez Sharpe, Nigel Clark, Dana Lowell
This paper reviews fuel-saving technologies for commercial trailers, provides an overview of the trailer market in the U.S., and explores options for policy measures at the federal level that can promote the development and deployment of trailers with improved efficiency. For trailer aerodynamics, there are many technologies that exist and are in development to target each of the three primary areas where drag occurs: 1) the tractor-trailer gap, 2) the side and underbody of the trailer, and 3) the rear end of the trailer. In addition, there are tire technologies and weight reduction opportunities for trailers, which can lead to reduced rolling resistance and inertial loss. As with the commercial vehicle sector, the trailer market is diverse, and there are a variety of sizes and configurations that are employed to meet a wide range of freight demands. Despite this great diversity, box-type vans represent more than two-thirds of the sales market and likely constitute a large percentage of total trailer miles traveled.
Technical Paper
2014-04-01
Mitsuru Enomoto, Michiko Kakinuma, Nobuhito Kato, Haruo Ishikawa, Yuichiro Hirose
Abstract Design work for truck suspension systems requires multi-objective optimization using a large number of parameters that cannot be solved in a simple way. This paper proposes a process-based systematization concept for ride comfort design using a set-based design method. A truck was modeled with a minimum of 13 degrees of freedom, and suspension performance under various vehicle speeds, road surface conditions, and load amounts was calculated. The range of design parameters for the suspension, the range of performance requirements, and the optimal values within these ranges were defined based on the knowledge and know-how of experienced design engineers. The final design of the suspension was installed in a prototype truck and evaluated. The performance of the truck satisfied all the objectives and the effectiveness of the set-based design approach was confirmed.
Technical Paper
2014-04-01
Andrew Pennycott, Leonardo De Novellis, Aldo Sorniotti, Patrick Gruber
The combination of continuously-acting high level controllers and control allocation techniques allows various driving modes to be made available to the driver. The driving modes modify the fundamental vehicle performance characteristics including the understeer characteristic and also enable varying emphasis to be placed on aspects such as tire slip and energy efficiency. In this study, control and wheel torque allocation techniques are used to produce three driving modes. Using simulation of an empirically validated model that incorporates the dynamics of the electric powertrains, the vehicle performance, longitudinal slip and power utilization during straight-ahead driving and cornering maneuvers under the different driving modes are compared. The three driving modes enable significant changes to the vehicle behavior to be induced, allowing the responsiveness of the car to the steering wheel inputs and the lateral acceleration limits to be varied according to the selected driving mode.
Technical Paper
2014-04-01
Reed Hanson, Rolf Reitz
Reactivity Controlled Compression Ignition (RCCI) is an engine combustion strategy that utilizes in-cylinder fuel blending to produce low NOx and PM emissions while maintaining high thermal efficiency. The current study investigates RCCI and conventional diesel combustion (CDC) operation in a light-duty multi-cylinder engine over transient operating conditions using a high-bandwidth, transient capable engine test cell. Transient RCCI and CDC combustion and emissions results are compared over an up-speed change from 1,000 to 2,000 rev/min. and a down-speed change from 2,000 to 1,000 rev/min. at a constant 2.0 bar BMEP load. The engine experiments consisted of in-cylinder fuel blending with port fuel-injection (PFI) of gasoline and early-cycle, direct-injection (DI) of ultra-low sulfur diesel (ULSD) for the RCCI tests and the same ULSD for the CDC tests. At the selected engine load, a step speed change was commanded and both combustion modes were compared for performance and emissions using fast response HC, NO and PM instruments.
Technical Paper
2014-04-01
Jonathan M. S. Mattson, Michael Mangus, Christopher Depcik
Abstract A timing sweep to correlate the location of Maximum Brake Torque (MBT) was completed on a single-cylinder, direct injected compression ignition engine that was recently upgraded to a high-pressure rail injection system for better engine control. This sweep included emissions monitoring for carbon dioxide, carbon monoxide, particulate matter, hydrocarbons, and oxides of nitrogen for the calibration of a heat release model, as well as the opportunity to relate MBT timing to brake-specific emissions production. The result of this timing sweep was a relatively linear correlation between injection delay and peak pressure timing. In addition, a number of other MBT timing methodologies were tested indicating their applicability for immediate feedback upon engine testing, particularly mass fraction burned correlations. Emissions were either strongly correlated to MBT timing (with emissions being minimized in the vicinity of MBT), or were completely independent of MBT. In addition, the end of the MBT timing envelope was linked to increased fuel consumption, as well as a rise in aromatic hydrocarbon emissions.
Technical Paper
2014-04-01
Scott Curran, Zhiming Gao, Robert Wagner
In-cylinder blending of gasoline and diesel to achieve reactivity controlled compression ignition (RCCI) has been shown to reduce NOX and PM emissions while maintaining or improving brake thermal efficiency as compared to conventional diesel combustion (CDC). The RCCI concept has an advantage over many advanced combustion strategies in that the fuel reactivity can be tailored to the engine speed and load allowing stable low-temperature combustion to be extended over more of the light-duty drive cycle load range. However, the current range of the experimental RCCI engine map investigated here does not allow for RCCI operation over the entirety of some drive cycles and may require a multi-mode strategy where the engine switches from RCCI to CDC when speed and load fall outside of the RCCI range. The potential for RCCI to reduce drive cycle fuel economy and emissions is explored here by simulating the fuel economy and emissions for a multi-mode RCCI-enabled vehicle operating over a variety of U.S. drive cycles using experimental engine maps for multi-mode RCCI with E30 and ULSD, CDC and a variety of 2009 port-fuel injected (PFI) gasoline engines ranging from 1.8L to 4.0L.
Technical Paper
2014-04-01
Richard R. Ruth, Jeremy Daily
Abstract 2013 and 2014 Ford Flex vehicles and airbag control modules with event data recorders (EDRs) were tested to determine the accuracy of speed and other data in the steady state condition, to evaluate time reporting delays under dynamic braking conditions, and to evaluate the accuracy of the stability control system data that the module records. This recorder is from the Autoliv RC6 family and this is the first known external research conducted on post 49CFR Part 563 Ford EDRs. The vehicle was instrumented with a VBox and a CAN data logger to compare external GPS based speeds to CAN data using the same synchronized time base. The vehicle was driven in steady state, hard braking, figure 8 and yaw conditions. The Airbag Control Module (ACM) was mounted onto a moving linear sled. The CAN bus data from driving was replayed as the sled created recordable events and the EDR data was compared to the reference instrumentation. The accuracy and timing of the data on a second stability control CAN bus was verified, and the transfer function between the CAN bus data and the EDR data was mapped, such that EDR data from any set of CAN data can be predicted.
Technical Paper
2014-04-01
Hiromu Soya, Makoto Yoshida, Kazutaka Imai, Yoshitaka Miura, Yuuki Matsushita
Abstract The new Jatco CVT8 High Torque (CVT8 HT) was developed for use on front-wheel-drive vehicles fitted with a large displacement engine. The development objectives set for this new CVT with a high torque capacity were outstanding fuel economy, size and weight reductions. To achieve those targets, a high torque capacity CVT chain was newly developed in cooperation with LuK GmbH & Co. KG. This article describes the efforts undertaken to develop increasing torque capacity.
Technical Paper
2014-04-01
Guang Wu, Xing Zhang, Zuomin Dong
Abstract Plug-in hybrid electric vehicles (PHEVs) with post-transmission parallel configuration attracted considerable attention due to their capacity to operate in either electric vehicle (EV) mode or hybrid electric vehicle (HEV) mode. Meanwhile, the added flexibility and multiple operation modes add additional challenges to vehicle control with acceptable drivability, particularly during the mode transition from the EV and HEV, since proper control is needed for the internal combustion engine (ICE), motor and coupling device to achieve smooth and fast transition, under various vehicle operation constraints such as mode-transition duration, vehicle acceleration fluctuation and friction loss of the dry clutch. In addition, the engagement of dry clutch features torque discontinuity due to slip-stick phenomenon and the dynamic behavior of the ICE further increases the nonlinearity of the powertrain system. This research introduces a method for identifying the theoretically optimal drivability during mode transition and feasible control schemes to effectively coordinate different powertrain components and achieve desirable drivability without violating vehicle operation constraints.
Technical Paper
2014-04-01
Bharadwaj Sathiamoorthy, Matthew C. Robinson, Evan Fedorko, Nigel Clark
Abstract Heavy duty tractor-trailers under freeway operations consume about 65% of the total engine shaft energy to overcome aerodynamic drag force. Vehicles are exposed to on-road crosswinds which cause change in pressure distribution with a relative wind speed and yaw angle. The objective of this study was to analyze the drag losses as a function of on-road wind conditions, on-road vehicle position and trajectory. Using coefficient of drag (CD) data available from a study conducted at NASA Ames, Geographical Information Systems model, time-varying weather data and road data, a generic model was built to identify the yaw angles and the relative magnitude of wind speed on a given route over a given time period. A region-based analysis was conducted for a study on interstate trucking operation by employing I-79 running through West Virginia as a case study by initiating a run starting at 12am, 03/03/2012 out to 12am, 03/05/2012. Results showed that vehicles which travelled the route on 03/04/2012 after 2pm were subjected to higher yaw angles (9 - 14 degrees) compared to vehicles travelling between 12am and 2pm on the same day.
Technical Paper
2014-04-01
Melanie Zielenski, Peter Downes, Darren Jelbert
Abstract Heavy duty diesel engine development has always faced high customer durability requirements, short development timelines and increasingly stringent emissions legislations. However, more frequently heavy duty engines are being used in multiple vehicle platforms across the globe with increasingly stringent quality demands in emerging markets. In order to meet engine life requirements, Delphi Diesel Systems has adapted accepted validation procedures to evaluate their system performance for the global market. In addition to durability and structural testing Delphi Diesel Systems has introduced specialized tests to validate their product at extremes of environmental conditions and fuel properties and has increased OEM collaboration. This paper details some of the adjustments made to the validation test suite to meet the specific challenges of the Heavy Duty market.
Technical Paper
2014-04-01
Jeff Howell, Kevin Garry, Jenny Holt
The influence of a large truck on the aerodynamics of a small passenger car in an overtaking manoeuvre on the motorway was considered, many years ago, during the 1970's, to be a potential problem for the vehicle aerodynamicist. The concern never became significant as vehicle architecture evolved and car weights increased. The current drive for improved fuel economy is advocating that a considerable reduction in vehicle mass is desirable and therefore it may be time to readdress the significance of the truck passing manoeuvre. A quasi-steady experiment has been undertaken at small model scale to examine the aerodynamic characteristics of a small car in proximity to a large truck. Measurements at yaw were included to crudely simulate the effects of a crosswind. The wind tunnel data is presented and the limitations of the experimental procedure are discussed. An estimate of the increased aerodynamic input on a car in a real world overtaking manoeuvre with relative velocity between the two vehicles is introduced.
Technical Paper
2014-04-01
Darrell Robinette
This investigation utilizes a DFSS analysis approach to determine automatic transmission gear content required to minimize fuel consumption for various powertrain - vehicle systems. L18 and L27 inner arrays with automatic transmission design and shift pattern constraint parameters were varied to determine their relative influence on fuel consumption. An outer noise array consisting of two vehicles with various engines, final drive ratios and legislated emissions test cycles was used to make a robust transmission selection based on minimizing fuel consumption. The full details of the DFSS analysis method and assumptions are presented along with a detailed examination of the results. With respect to transmission design parameters, parasitic spinloss and gear mesh efficiency were found to be most important followed by the number of gears. The DFSS analysis further revealed that unique transmission design formulations are potentially required for widely varying engines. The shift pattern constraint of minimum operating speed in gear that establishes the downshift line was found to be most significant while all other shift parameters proved to be negligible.
Book
2014-02-24
Jorge Segers
Racecar data acquisition used to be limited to well-funded teams in high-profile championships. Today, the cost of electronics has decreased dramatically, making them available to everyone. But the cost of any data acquisition system is a waste of money if the recorded data is not interpreted correctly. This book, updated from the best-selling 2008 edition, contains techniques for analyzing data recorded by any vehicle's data acquisition system. It details how to measure the performance of the vehicle and driver, what can be learned from it, and how this information can be used to advantage next time the vehicle hits the track. Such information is invaluable to racing engineers and managers, race teams, and racing data analysts in all motorsports. Whether measuring the performance of a Formula One racecar or that of a road-legal street car on the local drag strip, the dynamics of vehicles and their drivers remain the same. Identical analysis techniques apply. Some race series have restricted data logging to decrease the team’s running budgets.
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