Problems in Assessing Pneumatic Wheel Unbalance of a Passenger Car Determined with Test Road in Normal Conditions
Abstract The vibrations of the sprung mass of a passenger car, traveling along a road surface, are random. They also form its main source but there are besides other factors to consider. The resulting force ratio is overlapped by other phenomena occurring at the interface of the pneumatic tire with the road surface, such as non-uniformity of tires, shape deformations and imbalances. The resulting additional inertia force acts on the kinematic force that was previously induced on the car body. The vibrations of the sprung mass of the car body at the time can be considered as a potential source of diagnostic information, but getting insight their direct identification is difficult. Moreover, the basic identification is complicated because of the forces induced due to the random interference from road roughness. In such a case, the ratio defined as SNR assumes negative values.
Abstract Nighttime driving cannot be accomplished without vehicle headlighting. A growing body of evidence demonstrates the role of lighting on visual performance and in turn on nightttime driving safety in terms of crashes. Indirect impacts of lighting via comfort or other factors are less well understood, however. A two-part field study using real-world drivers of an instrumented vehicle was conducted to assess the potential role of oncoming headlight glare as a factor in driving behaviors that might be related to increased crash risks. In the first part of the study, drivers' behaviors when navigating through roadway intersections having different levels of crash risk were recorded in order to identify responses that were correlated with the risk level. In the second part, drivers were exposed to different levels of glare from oncoming headlights; several of the same risk-related behaviors identified in the first part of the study were exhibited.
Vehicle Lane Change Automation with Active Steering - Theoretical Studies and Numerical Investigations
Abstract Lane change automation appears to be a fundamental problem of vehicle automated control, especially when the vehicle is driven at high speed. Selected relevant parts of the recent research project are reported in this paper, including literature review, the developed models and control systems, as well as crucial simulation results. In the project, two original models describing the dynamics of the controlled motion of the vehicle were used, verified during the road tests and in the laboratory environment. The first model - fully developed (multi-body, 3D, nonlinear) - was used in simulations as a virtual plant to be controlled. The second model - a simplified reference model of the lateral dynamics of the vehicle (single-body, 2D, linearized) - formed the basis for theoretical analysis, including the synthesis of the algorithm for automatic control. That algorithm was based on the optimal control theory.
Abstract On-road fuel economy is known to vary significantly between individual trips in real-world driving conditions. This work introduces a methodology for rapidly simulating a specific vehicle’s fuel economy over the wide range of real-world conditions experienced across the country. On-road test data collected using a highly instrumented vehicle is used to refine and validate this modeling approach. Model accuracy relative to on-road data collection is relevant to the estimation of “off-cycle credits” that compensate for real-world fuel economy benefits that are not observed during certification testing on a chassis dynamometer.
Abstract In vehicles with urea-SCR system, normal operation of the urea-SCR system and engine will be influenced if there are deposits appearing on exhaust pipe wall. In this paper, a commercial vehicle is employed to study the influence factors of deposits through the vehicle road test. The results show that, urea injection rate, temperature and flow field have impacts on the formation of deposits. When decreasing the urea injection rate of calibration status by 20%, the deposit yield would reduce by 32%. If the ambient temperature decreased from 36 °C to 26 °C, the deposit yield would increase by 95%. After optimizing the exhaust pipe downstream of the urea injector by removing the step surface, only a few flow marks of urea droplets are observed on the pipe wall, and no lumps of deposits existing.
Comparison of Dynamic Performance and Fuel Consumption of Direct-drive and Overdrive Transmission Tractors
Abstract The main objective of this project was to compare the fuel consumption and dynamic performances of direct-drive and overdrive transmission tractors. Fuel consumption was evaluated at constant high speed and on various road profiles, while the dynamic performance was assessed on various road profiles only. The SAE Fuel Consumption Test Procedure (J1526) was used for constant high speed fuel consumption track test evaluations. The direct-drive transmission tractor consumed less than the overdrive transmission tractor, even though it was heavier. The testing on various road profiles was conducted using a towing dynamometer, for comparing the dynamic capability of the tractors when simulating the same towing load on two hilly road profiles: the Townes Pass path (in the Rocky Mountains) and the Saguenay path (in the Saguenay region of Quebec). Each tractor was to haul the set load along the given path while trying to attain 90 km/h speed.
Abstract Since more than eight years Vienna Engineering (VE) is working on an electro-mechanical brake (EMB) actuated by eccentrics and a highly non-linear actuation mechanism. The principle allows full braking in approx. 70 milliseconds (including air gap) and only approx. 3 A RMS actuator current at 12 V for classical ABS with oscillations. This EMB reached an elaborated state. Versions for passenger cars, elevators, railway and commercial vehicles (CVs) were derived. Now, as the EMB is going to road tests, it is necessary to fulfill safety requirements closely. What are these safety requirements and how can they be fulfilled? The properties of the overall system, of the mechanics and electronics of the single brake are discussed in this paper. The overall brake system for EMBs needs a truly redundant power supply, a safe control bus and a safe brake pedal. The mechanics of a single brake can be required to release when power is off and it must not get mechanically stuck.
Solving the Greenhouse Gas puzzle While automakers and policymakers debate the TAR, engineers and product planners prepare for the steep climb to meet GHG and CAFE rules beyond 2022. Revving up thermal characterization in the component lab The latest generation of high-speed infrared cameras can capture airbag deployments and other fast-moving actions quickly and accurately. C3 consortium aims for soot solution A newly formed group of companies led by CFD specialists Convergent Science targets exhaust particulate reduction in the combustion chamber. Inside the autonomous vehicle With less focus on driver needs, comfort, safety, and occupant productivity will become key. Editorial: Bad gas?
Enhancement of Full-Vehicle Road Noise Simulation Including Detailed Road Surface and Innovative Tire Modeling
Abstract The time to market in the automotive industry is constantly decreasing pushing the carmaker companies to increase the efforts in numerical simulations and to decrease the number of prototypes. In the NVH field, this time constraint reflects in moving the well-established finite element simulations towards the so called “full-vehicle simulations”. Specifically, the CAE techniques should be able to predict the complete behavior of the vehicles in mission conditions, so to reproduce some usual tests, such as the “coast down” test on different roads. The aim of this paper is to present a methodology to improve rolling noise simulations exploiting an integrated full-vehicle approach. An accurate modeling of all the subsystems is needed, with particular attention to the wheels and the suspension systems. Therefore, the paper firstly covers the modeling approach used to obtain the FE models of tires and suspension system.
Mercedes-Benz SLS AMG Coupé Electric Drive: NVH Development and Sound Design of an Electric Sports Car
Mercedes-AMG GmbH specializes in unique, high-performance vehicles. The image of AMG as the successful performance brand of Mercedes-Benz is reflected in its impressive successes in the world of motorsport and its unique vehicles. One of these vehicles is the SLS AMG Coupé Electric Drive. After an elaborate series of tests as well as numerous test drives, we have created the SLS eSound which captures the exceptional dynamism of this unique super sports car with electric drive. Starting with a characteristic start-up sound, which rings out on pressing the "Power" button on the AMG DRIVE UNIT, the occupants can experience a tailor-made driving sound for each driving situation: incredibly dynamic when accelerating, subdued when cruising and as equally characteristic during recuperation. The sound is not only dependent on road speed, engine speed and load conditions, but also reflects the driving situation and the vehicle's operating state with a suitable driving noise.
A 24-hour battle of speed and efficiency At Le Mans this month, amped-up hybrid prototype racecars from Audi and Toyota face a revamped Porsche 919 hybrid, while Ford hopes to recapture glory with its new GT-R. Pushing the ICE forward, gradually Emergent technologies from BorgWarner, Eaton and Mahle aim for greater efficiency in gasoline and diesel engines. Smile, you're on Magna camera! Magna Electronics is rapidly expanding production of its made-in-U.S.A. onboard cameras to keep pace with booming OEM demand for safety and vehicle-autonomy vision-systems technology. Multi-material body solutions: Possibilities and manufacturing challenges The body-in-white is a prime target for lightweighting and many automakers are pursuing unique and effective multi-material approaches, but improved design tools and processes might yield greater gains.
Abstract Pre-production vehicle validation is a critical step in understanding what potential issues end customers may find. Road profiles used in vehicle level tests are critical in finding failures. Clearly, if all the vehicles are tested only on highway, many failures will not be discovered. Therefore, using the right road profiles is very important. Traditionally, customer survey data is used to identify an appropriate road profile by defining a route that represents the Xth percentile customer. In this paper, a clustering method is applied to group all the customers into several groups. Each group is represented by a single road profile, and the entire customer population can be represented by multiple road profiles. If vehicles are tested using these profiles, then the road test can better represent the field condition, and hopefully failures can be discovered more efficiently.
Abstract The Aisin A465 6-Speed Diesel Hybrid powertrain started production in early 2012 and is available in the North American market in the Hino 195h DC COE truck. The suitability, and added fuel efficiency, of a Hybrid powertrain for Class 5 Box truck is very dependent on fleet usage conditions and duty cycle. Aisin has undertaken real-world, extended mileage, durability testing on public roads to determine the operational modes for which such a powertrain is most suitable, and for which a fleet owner can expect fuel savings that will result in a payback period justifying the higher cost of a hybrid system equipped commercial truck. Data collected on the same Aisin proprietary durability test routes with a Conventional Class 3-5 Cab Chassis truck provides insights into truck usage parameters that differ between Hybrid and Conventional Class 3-5 commercial trucks.
Multi-Target Tracking Algorithm in the Complicated Road Condition for Automotive Millimeter-wave Radar
Abstract Automotive radar is the most important component in the autonomous driving system, which detects the obstacles, vehicles and pedestrians around with acceptable cost. The target tracking is one of the key functions in the automotive radar which estimates the position and speed of the targets having regarding to the measurement inaccuracy and interferences. Modern automotive radar requires a multi-target tracking algorithm, as in the radar field of view hundreds of targets can present. In practice, the automotive radar faces very complicated and fast-changing road conditions, for example tunnels and curved roads. The targets’ unpredictable movements and the reflections of the electromagnetic wave from the tunnel walls and the roads will make the multi-target tracking a difficult task. Such situation may last several seconds so that the continuous tracks of the targets cannot be maintained and the tracks are dropped mistakenly.
Abstract Road tests on a pickup truck have been conducted to determine the acoustic loads on the back panel surfaces of the vehicle. Surface mounted pressure transducers arrays are used to measure both the turbulent flow pressures and the acoustic pressures. These measurements are used to determine the spatial excitation parameters used in an SEA model of the transmission loss through the back panel surfaces. Comparisons are made between tests on different road surfaces and at different speeds to identify the relative contributions of acoustic and wind noise.
This document is a road test procedure for comparing the corrosion resistance of both coated and uncoated sheet steels in an undervehicle deicing salt environment.
Application of PHEV Fractional Utility Factor Weighting to EcoCAR On-Road Emissions and Energy Consumption Testing
Abstract EcoCAR is North America's premier collegiate automotive engineering competition, challenging students with systems-level advanced powertrain design and integration. The EcoCAR Advanced Vehicle Technology Competition series is organized by Argonne National Laboratory, headline sponsored by the U.S. Department of Energy and General Motors, and sponsored by more than 30 industry and government leaders. In the last competition series, EcoCAR 2, fifteen university teams from across North America were challenged to reduce the environmental impact of a 2013 Chevrolet Malibu by redesigning the vehicle powertrain without compromising performance, safety, or consumer acceptability. This paper examines the results of the EcoCAR 2 competition’s emissions and energy consumption (E&EC) on-road test results for several prototype plug-in hybrid electric vehicles (PHEVs). The official results for each vehicle are presented along with brief descriptions of the hybrid architectures.
Abstract Considerable amounts of the everyday goods transports are done using light trucks. In the last ten years (2005-2015), the number of light trucks has increased by 33 % in Sweden. The majority of these light trucks are fitted with a swap body and encounter the same problem as many other truck configurations, namely that several different manufacturers contribute to the final shape of the vehicle. Due to this, the aerodynamics of the final vehicle is often not fully considered. Hence there appears to be room for improving the aerodynamic performance. In this study the flow around a swap body fitted to a light truck has been investigated using Computational Fluid Dynamics. The focus has been on improving the shape of the swap body in order to reduce both the aerodynamic drag and fuel consumption, while still keeping it usable for daily operations.
Abstract Proper tire pressure is very important for multiple driving performance of a car, and it is necessary to monitor and warn the abnormal tire pressure online. Indirect Tire Pressure Monitoring System (TPMS) monitors the tire pressure based on the wheel speed signals of Anti-lock Braking System (ABS). In this paper, an indirect TPMS method is proposed to estimate the tire pressure according to its resonance frequency of circumferential vibration. Firstly, the errors of ABS wheel speed sensor system caused by the machining tolerance of the tooth ring are estimated based on the measured wheel speed using Recursive Least Squares (RLS) algorithm and the measuring errors are eliminated from the wheel speed signal. Then, the data segments with drive train torsional vibration are found out and eliminated by the methods of correlation analysis.
50,000km On-Road Durability Test of Common-Rail Vehicle with 20% Blend of High Quality Palm Biodiesel (H-FAME)
Abstract The effects of high quality biodiesel, namely, partially Hydrogenated Fatty Acid Methyl Ester or H-FAME, on 50,000km on-road durability test of unmodified common-rail vehicle have been investigated. Thailand brand new common-rail light duty vehicle, Isuzu D-Max Extended cab, equipped with 4JK1-TCX engine (DOHC 4-cylinder 2.5L, M/T 4×2, Euro IV emission) was chosen to undergo on-road test composed of well-mixed types of mountain, suburb and urban road conditions over the entire 50,000km. Palm-derived high quality biodiesel, H-FAME, conforming to WWFC (worldwide fuel charter) specification, was blended with normal diesel (Euro IV) at 20% (v/v) as tested fuel. Engine performance (torque and power), emission (CO, NOx, HC+NOx and PM), fuel consumption and dynamic response (0-100km acceleration time and maximum velocity) were analyzed at initial, middle and final distance; whereas, used lube oil analysis was conducted every 10,000km.
Abstract Steering and suspension system has to be designed properly to achieve improved handling characteristics. Improper design of steering systems will result in steering errors such as bump steer and roll steer. These steering errors results in reduced steering performance. During the design of steering system the tie rod length has to be properly selected to reduce these steering errors. The purpose of the work is to analyze the effects of tie rod length variation on bump steer. Multi body dynamic model of the selected vehicle was created using MSC ADAMS Car software. Ideal design of steering system to achieve zero bump steer was created. The tie rod length was later varied up to 10% to study the effect of varying length on bump steer. Parallel wheel travel analysis was conducted to study the tie rod length variation on bump steer. Acceleration test was conducted on a flat road having bump to analyze the effect of changing tie rod length on steering performance of the vehicle.
This document aims to establish best practices in equipment setup and measurement of brake rotor disk thickness variation (DTV) on vehicle.
Abstract The experimental measurement of the energy consumption and efficiency of Battery Electric Vehicles (BEVs) are key topics to determine their usability and performance in real-world conditions. This paper aims to present the results of a test campaign carried out on a BEV, representative of the most common technology available today on the market. The vehicle is a 5-seat car, equipped with an 80 kW synchronous electric motor powered by a 24 kWh Li-Ion battery. The description and discussion of the experimental results is split into 2 parts: Part 1 focuses on laboratory tests, whereas Part 2 focuses on the on-road tests. As far as on-road tests are concerned, the vehicle has been tested over three different on-road routes, ranging from 60 to 90 km each, with a driving time ranging from approximately one and half to two and half hours.
Aerodynamic Drag Reduction - from Conceptual Design on a Simplified Generic Model to Full-Scale Road Tests
Abstract Road transportation by trucks is the major part of the goods transportations system in the European Union (EU), and there is a need for increased fuel efficiency. While truck manufacturers already spend significant resources in order to reduce the emissions from their vehicles, most truck manufacturers do not control the shape of the trailer and/or swap bodies. These devices are usually manufactured by different companies that cannot consider the overall aerodynamics around the complete vehicle. By use of Computational Fluid Dynamics (CFD) and previous wind tunnel experiments, the flow around a simplified generic tractor-trailer model has been investigated. With better understanding of the flow features around the tractor with attached trailer or swap bodies, an improved design of the trailer and swap body can be achieved, which is the aim for the project.
Guidelines for Safe On-Road Testing of SAE Level 3, 4, and 5 Prototype Automated Driving Systems (ADS)
This document provides guidelines for the safe conduct of on-road tests of vehicles equipped with prototype conditional, high, and full (levels 3-5) automated driving systems (ADSs), as defined by SAE J3016. It does not include guidance for testing production ADSs intended for sale to the general public. The scope is further limited to testing of automated prototype vehicles on public roads. These guidelines do not address: Testing of driver assist (Level 1) or partial (Level 2) automation systems, which rely on a human driver to monitor the environment. (See SAE J3016 for Definitions of Levels of Automated Systems.) Closed-course testing. Component-level testing. The precise regime of road testing for a particular prototype will depend on the intended level of automation and the targeted capabilities of the prototype (see SAE J3016 for more information).
Assessment Methodologies for Forward Looking Integrated Pedestrian Systems and Further Extension to Cyclist Safety: Experimental and Virtual Testing for Pedestrian Protection
Abstract Pedestrians and cyclists are the most unprotected road users and their injury risk in case of accidents is significantly higher than for other road users. The understanding of the influence and sensitivity between important variables describing a pedestrian crash is key for the development of more efficient and reliable safety systems. This paper reflects the related work carried out within the AsPeCSS project. The results summarized out of virtual and physical tests provide valuable information for further development. 1168 virtual and 120 physical tests were carried out with adult and child pedestrian headform as well as upper and lower legform impactors representatives of 4 different vehicle front geometries in a wide range of impact speeds, angles and locations. This test matrix was based on previous work carried out within the AsPeCSS project.
Time-Resolved Estimation of Fuel Consumption Breakdown of a Heavy Duty Truck Under Actual Road Conditions
Fuel economy and performance vary significantly with the vehicle design and configuration, road profile, and payload. The variation is more pronounced for heavy-duty trucks and understanding its origin is critical to maximizing fleet profitability. In this paper we demonstrate a method to continuously estimate fuel consumption breakdown over resistive forces while the vehicle is driven on a public highway. The method is fast, cost-effective, and capable of analyzing trip segments as short as one second. The method utilizes a non-linear Kalman filter and a vehicle dynamical model that has a coupled longitudinal and vertical motion. The paper presents the breakdown of fuel consumption and an estimate of road grade profile obtained by driving a heavy-duty vehicle at the MnROAD research facility in Albertville MN.
Abstract Assessment of braking performance that includes brake fade is a critical part of the evaluation of military light tactical vehicles as it is for conventional light cars and trucks. These vehicles are sometimes called upon to operate in severe mountain regions that challenge the braking performance well beyond the environment in which these vehicles are normally operated. The U.S. Army Test Operating Procedure (TOP) 2-2-608 includes a test schedule conducted in the mountainous region near Jennerstown, Pennsylvania. While this test procedure represents a typical mountain environment, it does not represent the most severe mountain descents that can be encountered across the United States. As a preliminary step to developing a representative severe mountain descent braking test, mountain roads throughout the United States were evaluated analytically to identify potential test venues.
This SAE Recommended Practice establishes a uniform procedure for a flat-road simulation of a mountain-fade test of the brake systems of light-duty trucks and multipurpose passenger vehicles up to and including 4500 kg (10 000 lb) GVW and all classes of passenger cars.
Abstract A new electric powertrain and axle for light/medium trucks is presented. The indoor testing and the simulation of the dynamic behavior are performed. The powertrain and axle has been produced by Streparava and tested at the Laboratory for the Safety of Transport of the Politecnico di Milano. The tests were aimed at defining the multi-physics perfomance of the powertrain and axle (efficiency, acceleration and braking, temperature and NVH). The whole system for indoor tests was composed by the powertrain and axle (electric motor, driveline, suspensions, wheels) and by the test rig (drums, driveline and electric motor). The (driving) axle was positioned on a couple of drums, and the drums provided the proper torques to the wheels to reproduce acceleration and braking. Additionally a cleat fixed on one drum excited the vibration of the suspensions and allowed assessing NVH performance. The simulations were based on a special co-simulation between 1D-AMESIM and VIRTUAL.LAB.