Browse Topic: Trailers

Items (267)
This SAE Standard applies to upper coupler kingpins for commercial trailers and semitrailers in the unladen condition. See Figure 1. A 90 degree ± 1 degree angle extends (in all directions) from the centerline of the kingpin to the upper coupler plate surface within a 48.26 cm (19 inch) radius. The upper coupler plate surface should not bow downward (convex) more than 0.635 cm (1/4 inch) within a 48.26 cm (19 inch) radius or more than 0.3175 cm (1/8 inch) at a radius of 25.4 cm (10 inches) from the kingpin. The upper coupler plate surface should not bow upward (concave) more than 0.15875 cm (1/16 inch) within a 48.26 cm (19 inch) radius. (See Figure 2.)
Truck and Bus Total Vehicle Steering Committee
This study provides a simulation-based comparative analysis of the distance and time needed for long combination vehicles (LCVs) - namely, A-doubles with 28-, 33-, and 48-ft trailers - to safely exercise an emergency, evasive steering maneuver such as required for obstacle avoidance. The results are also compared with conventional tractor-semitrailers with a single 53-ft trailer. A multi-body dynamic model for each vehicle combination is developed in TruckSim® with an attempt to assess the last point to steer (LPTS) and evasive time (ET) at various highway speeds under both dry and wet road conditions. The results indicate that the minimum avoidance distance and time required for the 28-ft doubles vary from 206 ft (60 mph) to 312 ft (80 mph) and 2.3 s to 2.6 s, respectively. The required LPTS represents a 6% to 31% increase when compared with 53-ft semitrucks. When driving below 76 mph on a dry road and below 75 mph on a wet road, the 28-ft doubles exhibit LPTS and ET that are larger than 33-ft doubles. In addition, the 33-ft doubles exhibit larger LPTS and ET than 48-ft doubles for the highway speeds considered. This is mainly attributed to the longer trailer wheelbase that causes smaller rear trailer amplifications. At speeds higher than 76 mph on dry roads and 75 mph on wet roads, however, an opposite trend is observed. As the trailer length increases, the distance and time needed to safely avoid an obstacle also increase. A comparison between dry and wet road conditions is also conducted, with the results indicating that more time and distance would be needed for obstacle avoidance on wet roads.
Chen, YangZhang, ZichenAhmadian, Mehdi
Evaluation of General Motors Event Data Recorder Performance in Semi-Trailer Rear Underride Collisions2020-01-13284/14/2020
The objective of this study was to analyze the validity of airbag control module data in semi-trailer rear underride collisions. These impacts involve unusual collision dynamics, including long crash pulses and minimal bumper engagement [1]. For this study, publicly available data from 16 semi-trailer underride guard crash tests performed by the Insurance Institute for Highway Safety (IIHS) were used to form conclusions about the accuracy of General Motors airbag control module (ACM) delta-V (ΔV) data in a semi-trailer rear underride scenario. These tests all utilized a 2009 or 2010 Chevrolet Malibu impacting a stationary 48’ or 53’ semi-trailer at a speed of 35 mph. Nine tests were fully overlapped collisions, six were 30% overlapped, and one was 50% overlapped [2]. The IIHS test vehicles were equipped with calibrated 10000 Hz accelerometer units. Event Data Recorder (EDR) data imaged post-accident from the test vehicles were compared to the reference IIHS data. For each test, root mean square error (RMSE), the percent error over time, and the difference between the EDR ΔV and the IIHS ΔV, was quantified, plotted, and related to crash pulse. This analysis revealed a general trend of decreasing EDR ΔV parity with an increasing crash pulse duration, although overall differences remained low for most tests. Eleven tests, all with airbag deployments, converged towards an average of 3.3% error at the end of the crash pulse, which were 150-270 ms. EDR recorded ΔVs were in the range of 29.8-39.9 mph. Five tests, three of which were non-deployments, diverged to higher percentage error averaging 12.7% at an EDR ΔV of 31.8-40.0 mph. All higher error tests were 30% overlapped and had the highest crash pulse durations of 240-300 ms. One fully overlapped test generated highly unusual EDR data due to failure of the rear underride guard mounting bolts and plates.
Famiglietti, NicholasHoang, RyanFatzinger, EdwardLanderville, Jon
Comparative Analysis between American and European Requirements for Electronic Stability Control (ESC) Focusing on Commercial Vehicles2019-01-21419/15/2019
Analysis of road accidents has shown that an important portion of fatal crashes involving Commercial Vehicles are caused by rollovers. ESC systems in Commercial Vehicles can reduce rollovers, severe understeer or oversteer conditions and minimize occurrences of jackknifing events. Several studies have estimated that this positive effect of ESC on road safety is substantial. In Europe, Electronic Stability Control (ESC) is expected to prevent by far the most fatalities and injuries: about 3,000 fatalities (-14%), and about 50,000 injuries (-6%) per year. In Europe, Electronic Stability Control Systems is mandatory for all vehicles (since Nov. 1st, 2011 for new types of vehicle and Nov. 1st, 2014 for all new vehicles), including Commercial Vehicles, Buses, Trucks and Trailers. On 2015, NHTSA published Federal Motor Vehicle Safety Standard (FMVSS) No. 136, Electronic Stability Control systems for heavy vehicles, requiring Electronic Stability Control (ESC) systems on truck tractors and buses with a gross vehicle weight rating greater than 11,793 kilograms (26,000 pounds) for implementation in 2017. In South America, CONTRAN Resolution 641/2016 establishes mandatory installation of Electronic Stability and Rollover Control in Commercial Vehicles, including Trailers (Jan. 1st, 2022 for new types of vehicle and Jan. 1st, 2024 for all new vehicles). However there isn’t a Brazilian standard to validate the system and its performance shall comply with ECE R13 (Annex 21) or FMVSS 136, as applicable. This paper shows a technical review regarding ESC function, its impact on Commercial Vehicles and clarifies the different systems available for trucks and trailers, considering the differences between stability control systems - full stability and roll-only stability. In addition it will show a comparative analysis between American and European requirements and procedures to validate these vehicles safely.
Iombriller, Silvia FariaBolognesi Prado, WesleySilva, Marco Andre
Analysis of the Tractor-Trailer Dynamics during Braking2019-01-21449/15/2019
The intensive development of tractor-building industry in the world has led to the widespread use of wheeled tractors and tractor trains in transportations on public highways. This requires an increase of engine capacity and speed of tractor trains, as well as strict demands for their braking systems. The formation of the necessary braking properties of wheeled tractors and tractor trains on their basis should be carried out at the design phase, taking into account a wide range of aggregated machines and tools. Blocking the wheels of the trailer with different sequence of their blocking and blocking the wheels of the tractor has significant impact on the total braking force, deceleration and stability of the tractor train. It is advisable to take this into account when modeling the braking process of a tractor train. The article deals with the braking dynamics of the tractor train and the impact of the dynamic distribution of normal reactions between the axles on the brake properties of the tractor train. The mathematical model of the braking process of the tractor-trailer train (consisting of a wheeled tractor and a two-axle trailer at the limit of blocking the wheels) has been obtained. The coefficients of the total braking force distribution between the to the front and rear axles of the tractor, front and rear axles of the trailer, ensuring the directional stability of the tractor-trailer train, have been determined.
Podrigalo, MikhailKlets, DmytroKholodov, MykhailoKlimenko, ValeriyRudzinskyi, VolodymyrKholodov, Anton
An Experimental Study of the Impact of Underbody Roughness on the Instantaneous Wake Flow Topology behind a Truck Geometry2018-01-07144/3/2018
The turbulent wake behind a truck is responsible for a considerable proportion of the total aerodynamic drag. There is evidence to suggest that the underbody flow affects the wake topology, although this interaction is not well understood. Typical truck trailer underbodies are geometrically very complex and have a range of bluff bodies - such as the wheel and axle assembly, structural beams or the secondary fuel tank for refrigerated trucks - attached. These components block the underbody flow and erode its momentum. However, most of the previous studies of the wake flow have used models with clean underbodies. It is thus uncertain whether the wake shapes found by these studies accurately represent the wake topology behind a real truck with a detailed underbody. The aim of this study is therefore to investigate whether aerodynamic studies working with simplistic underbodies may observe a different wake pattern to those studies that correctly replicate the aerodynamic effects of a realistic underbody. This work uses two models. The first is a simple 1/10th scale model with the basic geometry and aspect ratio of a generic HGV. An underbody roughness pattern, which simulates the effect of the geometric complexity found in typical underbodies and that represents the standard blockage caused by common underbody components, is attached to the underside of the model. The structure of the wake behind the model is studied when the roughness pattern covers an increasing proportion of the total underbody. The observations made are compared to those seen for a configuration with a smooth underbody. The second model consists on a full 1/10th scale truck model with a detailed underbody and rotating wheels. Testing is conducted in a water tow tank, which establishes correct ground conditions. The facility operates at a Reynolds Number of approximately Re = 6.9 x 105. Optical access into the underbody and the near wake is possible through the clear working section of the facility. Stereoscopic Particle Image Velocimetry is used to analyse the flow field. It is found that underbody blockage and / or roughness considerably affects the wake topology and leads to a greater interaction between the low momentum flow in the wake and the higher momentum flow around it. Underbody roughness also increases the size of the region where the low momentum flow is concentrated, which expands laterally outwards away from the model center plane to a greater extent than for the smooth configuration. It is expected that the impact of underbody components on the wake flow structure may also affect the aerodynamic drag associated to the wake. This emphasizes the importance of improving the understanding of the interaction between the underbody and wake flows with drag reduction objectives in mind.
Vallina Garcia, IsabelBabinsky, Holger
Simplifications Applied to Simulation of Turbulence Induced by a Side View Mirror of a Full-Scale Truck Using DES2018-01-07084/3/2018
In this paper, the turbulent flow induced by a production side-view mirror assembled on a full-scale production truck is simulated using a compressible k-ω SST detached eddy simulation (DES) approach -- the improved delayed DES (IDDES). The truck configuration consists of a compartment and a trailer. Due to the large size and geometric complexity of the configuration, some simplifications are applied to the simulation. A purpose of this work is to investigate whether the simplifications are suitable to obtain the reasonable properties of the flow near the side-view mirror. Another objective is to study the aerodynamic performances of the mirror. The configuration is simplified regarding two treatments. The first treatment is to retain the key exterior components of the truck body while removing the small gaps and structures. Furthermore, the trailer is shaped in an apex-truncated square pyramid. This simplification is proposed based on the assumption that the downstream flow near the trailer has limited effect on the flow near the mirror. To assess the influences of the simplifications, the flow fields computed from the original and simplified configurations are compared. The regions on the window that are subjected to significant hydrodynamic impingement are identified. The mirror and A-pillar introduce the impingement. The frequency spectra of the surface pressure fluctuations on the window are studied. The frequencies of the peaks in the spectra are the same as the characteristic frequencies of the free shear layers that develop from the mirror side-edges near the window. The simplifications are found as feasible treatments to reproduce the flow characteristics of the original geometry.
Yao, HuadongChroneer, ZenithaDavidson, Lars
Aerodynamic Drag of a Vehicle and Trailer Combination in Yaw2017-01-15403/28/2017
Typical production vehicle development includes road testing of a vehicle towing a trailer to evaluate powertrain thermal performance. In order to correlate tests with simulations, the aerodynamic effects of pulling a trailer behind a vehicle must be estimated. During real world operation a vehicle often encounters cross winds. Therefore, the effects of cross winds on the drag of a vehicle–trailer combination should be taken into account. Improving the accuracy of aerodynamic load prediction for a vehicle-trailer combination should in turn lead to improved simulations and better thermal performance. In order to best simulate conditions for real world trailer towing, a study was performed using reduced scale models of a Sport Utility Vehicle (SUV) and a Pickup Truck (PT) towing a medium size cargo trailer. The scale model vehicle and trailer combinations were tested in a full scale wind tunnel. Utilizing a full scale wind tunnel allowed for very low blockage conditions and testing at large yaw angles by placing both the vehicle and the trailer entirely on the wind tunnel turntable and balance. This unique setup allowed for the measurement of all aerodynamic forces and moments on the vehicle, which could be used to improve vehicle dynamics modeling of a vehicle-trailer combination. The results of this paper show that the forces and moments on a vehicle-trailer combination change significantly at large yaw angles, and that zero yaw testing may be insufficient to predict the real world aerodynamic performance.
Lopes, Yuri M.Taylor, Maxwell R.Lounsberry, Todd H.Fadler, Gregory J.
Vibration Frequencies and Vertical Acceleration Levels Assessment on a Truck Trailer Chassis Considering Various Types of Pavement and Load Conditions2016-36-00675/11/2016
This paper presents several tests carried out on a truck trailer on different types of pavement and load condition, using proving ground tracks and facilities, the instrumentation details, data analysis and validation. Through an extensive analysis of Brazilian goods road transport, a load vehicle combination and a list of test pavements were chosen as off-road pavement, highway pavement, pot holes, washboard, cobblestones and Belgian blocks. Accelerometers were installed throughout the truck trailer chassis longitudinal length in order to obtain the acceleration levels and vibration frequencies on the truck trailer sprung mass. Aiming to evaluate the base excitation imposed to parts mounted to the truck trailers chassis, according to their mounting position, data processing method and cutoff frequency definition strategies were defined. After the results analysis and chassis acceleration level verification, power spectral densities were generated for each instrumented point of each test track and load condition to compare the truck trailer application requirements considering energy levels and most relevant frequencies. The main objective of this paper consists in the vertical vibration characterization which truck trailer components are subjected to, according to pavement type, load condition and longitudinal mounting position on a truck trailer chassis structure enabling a component differentiation for distinct applications even in the concept stage, designing more properly, reducing development costs and time. Furthermore, a test information database could be created to be used in a new laboratory test device in the future, capable to perform durability tests in a more accurate way regarding to the real application.
de Godoy José, GustavoRebelatto, MauroSchwanke, Rui Gustavo LippertStrohaecker, Telmo Roberto
An Experimental Study on Truck Side-Skirt Flow2016-01-15934/5/2016
The underbody of a truck is responsible for an appreciable portion of the vehicle’s aerodynamic drag, and thus its fuel consumption. This paper investigates experimentally the flow around side-skirts, a common underbody aerodynamic device which is known to be effective at reducing vehicle drag. A full, 1/10 scale European truck model is used. The chassis of the model is designed to represent one that would be found on a typical trailer, and is fully reconfigurable. Testing is carried out in a water towing tank, which allows the correct establishment of the ground flow and rotating wheels. Optical access into the underbody is possible through the clear working section of the facility. Stereoscopic and planar Particle Image Velocimetry (PIV) set-ups are used to provide both qualitative images of and quantitative information on the flow field. The planar PIV set-up employs novel techniques developed in-house, including the use of two laser sheets to reduce shadow regions, and frame averaging such that presented results are produced using an average of up to 1800 independent data points. It is shown that one drag-reducing mechanism of side-skirts at zero-degree yaw is the prevention of high-momentum flow at the side of the vehicle entering the upper half of the underbody. However, the flow topology varies significantly with vertical position, and side-skirts are shown to have effects on near-ground flow which could have a detrimental effect on vehicle drag. It is therefore likely that an optimum value exists for the height of a side-skirt from the ground.
Stephens, R.G.Babinsky, H.
Handling-Stability Oriented Parameter Optimization for a Tractor Semi-Trailer Vehicle2015-01-27539/29/2015
Tractor semi-trailer as a widely-used heavy duty freight vehicle has caused many fatal accidents every year and one of the main factors of which may relate to its relatively poor lateral dynamics performance compared to the passenger cars [1, 2, 3]. In this paper, attention is concentrated on the parametric design for a tractor semi-trailer by optimizing the configuration parameters aiming to comprehensively improve the lateral dynamics performance. According to the previous public reports, the performance measures such as Load Transfer Ratio (LTR), Static Rollover Threshold (SRT), Rearward Amplification Ratio (RAR) and Ratio of Yaw Rate (RYR) are very effective measures and often be used to evaluate the handling and stability performances for tractor-trailer vehicles. However, each of those measures only pays attention to a certain aspect of vehicle lateral dynamics which is closely related to vehicle configuration parameters. Especially, the load scenario in transport which often varies from one task to another can make the lateral dynamics change considerably. Therefore it is difficult for a vehicle to obtain a comprehensively satisfying handling-stability performance in a wide range of load scenarios. In this work, two relatively comprehensive measures which directly link with vehicle configuration parameters have been formulated based on multivariable linear regression (MVLR) method respectively corresponding to the body roll and yaw dynamics in order to facilitate the implementation of handling- stability oriented design method. As an example, an optimal design scheme based on Multi-Objective Linear Programming (MOLP) method is presented and a set of optimum parameters are obtained. The handling and stability performances after optimization have been compared with those before optimization by simulations in TruckSim.
Yang, XiujianZhu, RuochengGao, Jin
The Traction: Electric Drive of the Active Trailer for Pipe Transportation2015-01-28239/29/2015
In this paper, we consider the hybrid power train for transportation of long pipes with big diameter. It is includes diesel engine for main towing vehicle and auxiliary electric drive for the active trailer The trains with active trailers are necessary at the building of oil and natural gas pipelines in no road conditions and marshlands. Due to the electric drive, the trailer's off-road capability on marshland conditions is sharply increased and its control is facilitated. The specified attractive qualities are appeared, if wheels of the trailer are executed as drivable, and the kinematic circuit of a drive is fulfilled as one-stage. At this, it is taken in attention that power of the electric drive will take 20 - 25 % from rated power of the basic traction drive, with the expanded range of torque control (till 1:10 and more). Such overloads are provided by the electric drive with synchronous reluctance machine of independent excitation developed by authors. It is offered techniques, allowing choose rational ratio of values range control of the torque. Mathematical model the electric drive is suggested and executed. The model describes mechanical and electromechanical transformation of energy. In a control system of the electric drive, the classical circuit of the subordinated control is chosen. The electric drive is executed as the multi loop control system, which contain loops of the stator phase currents control, torque of the engine, and the speed. The model takes into account nonlinearity of motor core curve magnetization. Modes, of start the electric drive, slipping and skidding of wheels are considered also.
Usinin, UriyGladyshev, SergeyGrigoryev, MaximShishkov, AlexanderBelousov, EvgenyZhuravlev, A. M.Bychkov, AntonSychev, Dmitry
Retroreflective DOT-C2 Tape Performance in Relation to Observation and Entrance Angle - A Real World Study2015-01-14324/14/2015
Accident reconstruction experts are often asked to evaluate the visibility and conspicuity of objects in the roadway. It is common for objects placed in or along the roadway, vehicles, and required by Federal Motor Vehicle Safety Standard (FMVSS) No. 108 for certain vehicles and trailers, to have red and white DOT-C2 retroreflective tape installed on several locations. Retroreflective tape is designed to reflect light back towards the light source at the same entrance angle. The authors' literature review revealed that there have been no publications quantifying the performance of commercially available DOT-C2 retroreflective tape with real world vehicles. Therefore, without additional study, an accident reconstruction expert cannot know exactly how a specific type of compliant tape would perform beyond the minimum federal requirements. In the current research, the performance of white and red DOT-C2 retroreflective tape is quantified. Using different vehicles, with differing headlight housings, bulb types, headlight height, occupant seating height, and headlight spacing, the performance of different types and manufacturers of retroreflective tape was quantified at different entrance angles. The authors attempted to study a range of popular, commercially available, DOT-C2 retroreflective tape. In this study, 3M 963, 3M 983, Grote, and Trucklite DOT-C2 retroreflective tape were used. The effect of change in observation angle and entrance angle were studied. Preliminary research was performed on the effect of measuring luminance through a vehicles windshield, which has factory tinting, versus outside of the vehicle, not through the windshield. From the current study, it was determined that the entrance angle and the observation angle affected the performance of all of the retroreflective tapes, with lower performance at higher entrance angles and/or observation angles. It was also determined that the white retroreflective tape had higher performance than the red retroreflective tape for every tape type tested. Finally, it was determined that the performance of the tape decreased when measured through the windshield of the vehicle, versus from outside of the vehicle.
Suway, Jeffrey AaronWelcher, Judson
Design and Control of Vehicle Trailer with Onboard Power Supply2015-01-01324/14/2015
Typically, when someone needs to perform occasional towing tasks, such as towing a boat on a trailer, they have two choices. They can either purchase a larger, more powerful vehicle than they require for their regular usage, or they can rent a larger vehicle when they need to tow something. In this project, we propose a third alternative: a trailer with an on-board power supply, which can be towed by a small vehicle. This system requires a means of sensing how much power the trailer's power supply should provide, and an appropriate control system to provide this power. In this project, we design and model the trailer, a standard small car, and the control system, and evaluate the concept's feasibility. We have selected a suitable power source for the trailer, a DC motor, coupled directly to the trailer's single drive wheel, which allow us to dispense with the need for a differential. The trailer hitch is designed to include force sensing capability, to determine whether the trailer is moving under its own power or being towed by the vehicle. There is a control system, designed to maintain a zero force in the hitch, thus ensuring that the trailer is providing enough power. This system will enable someone with occasional towing needs to perform these tasks with their standard vehicle, and avoid the need for a larger vehicle.
Sankara Narayanan, Sibi VishtPeters, Diane
Design of Live Gooseneck Multi-Axle Trailer and Experimental Validation by Simulated Static Load Test2015-26-01501/14/2015
Special purpose, high payload carrying capacity, live gooseneck, multi axles, hydraulic suspension semi trailer is abinitio designed for transportation and tilting of heavy cargo from horizontal to vertical by hydraulically actuated mechanism integrated on the trailer. The chassis is levelled on hydraulic jacks followed by tilting of cargo. Hence the chassis experiences variable forces during tilting and estimated from kinematic model of tilting mechanism. These forces are input for finite element based structural design of chassis. Structural deflection of a step is made as initial condition for certain load cases of the analysis. Live gooseneck of this semi-trailer consists of hydraulically actuated mechanism, interconnected with multiple hydraulic suspensions in appropriate ratios. Estimation of Axles and fifth wheel force distributions of such trailer is complex. Mathematical modelling made to estimate these forces and applied as inputs for finite element analysis. Simulated static load test set-up is designed for experimental validation of finite element analysis. One low cost innovative static fixture arrangement, which is entirely different from actual tilting mechanism, is developed for controlled application of simulated forces on the chassis. The strain gauging is made at various predetermined locations of trailer chassis and strains are recorded during simulated load test by static fixture as a part of acceptance test plan. Deflections are also measured at different locations of the chassis. The recorded strain and deflection values are analysed, correlated and validated with results obtained from Finite Element Analysis. Method established for design and validation of live gooseneck trailer.
Chaudhuri, SanjaySaini, Vikram
Heavy-Duty Vehicle Rear-View Camera Systems2014-01-23819/30/2014
Transport Canada, through its ecoTECHNOLOGY for Vehicles program, retained the services of the National Research Council Canada to undertake a test program to examine the operational and human factors considerations concerning the removal of the side mirrors on a Class 8 tractor equipped with a 53 foot dry van semi-trailer. Full scale aerodynamic testing was performed in a 2 m by 3 m wind tunnel on a system component basis to quantify the possible fuel savings associated with the removal of the side mirrors. The mirrors on a Volvo VN780 tractor were removed and replaced with a prototype camera-based indirect vision system consisting of four cameras mounted in the front fender location; two cameras on either side of the vehicle. Four monitors mounted in the vehicle - two mounted on the right A-pillar and two mounted on the left A-pillar - provided indirect vision information to the vehicle operator. Four commercial drivers were asked to perform a series of tests simulating typical driving scenarios on a closed course test track. The tests included an object identification test, a blind spot comparison test, a coupling and uncoupling test, a quasi-static lane change test, a dynamic lane change test and an evasive manoeuvres test. The tests were performed both with the mirrors and with the camera-based indirect vision system. The results of the study provide an analysis of driver performance while using the mirrors in comparison to driver performance while using the camera-based indirect vision system. Driver acceptance of the camera-based indirect vision system was also analyzed through the use of questionnaires.
McWha, Tyson
An Active Long-Travel, Two Performance Loop Control Suspension of an Open-Link Locomotion Module for Off-Road Applications2014-01-22889/30/2014
An open-link locomotion module (OLLM) is an autonomous energy self-sufficient locomotion setup for designing ground wheeled vehicles of a given configuration that includes drive/driven and steered/non-steered wheels with individual suspension and brake systems. Off-road applications include both trucks and trailers. The paper concentrates on the module's electro-hydraulic suspension design and presents results of analytical and experimental studies of a trailer with four driven (no wheel torque applied) open-link locomotion modules. On highly non-even terrain, the suspension design provides the sprung mass with sufficient vibration protection at low level of normal oscillations, enhanced damping and stabilized angular movements. This is achieved by the introduction of two control loops: (i) a fast-acting loop to control the damping of the normal displacements; and (ii) a slow-acting control loop for varying the pressure and counter-pressure in the suspension system. Thus, two separate but coordinated controls were designed for both loops to act under small (less than ±7 degrees) and big (larger than ±7 degrees) pitch and roll angles of a vehicle designed with a set of the modules. The control actions in both loops of each module are distributed among the trailer's modules through three control channels: one channel to damp normal oscillations of each module and another two channels to stabilize the pitch and roll angles. This paper presents details on the loop controls and the channels and shows the ride efficiency of the suspension system in the 0.5-10 Hz frequency range of the sprung mass vibrations; some details on potential break-down (bottoming) of the suspension prototype are provided based on experimental study of a newly designed trailer with four open-link locomotion modules. Many other suspension design problems (including suspension bandwidth, power requirements, etc.) are not in the scope of the paper.
Belousov, BorisKsenevich, Tatiana I.Vantsevich, VladimirNaumov, Sergei
Effects of Liquid Cargo on Lateral Stability of B-Train Combination2014-01-23199/30/2014
Road train vehicles have been applied as one of the common and efficient ways for transportation of goods, specifically hazardous liquid cargos, in different nations. These vehicles have a wide variety of lengths and towing systems such as the fifth wheel or the dolly draw-bar. Based upon specific regulations, they could be authorized to move on specific roads. In order to avoid hazard and danger in case of accidents, safety performance of a B-train vehicle as a specific type of road train vehicles is investigated in this paper. A Multi-Body Dynamic (MBD) model, which consists of a prime mover and two trailers coupled by fifth wheels, are simulated in the initial phase of the study. The developed dynamic model is capable of simulating required tests as well as the SAE lane change, along with a constant radius turn for the purpose of roll and yaw stability analysis and safety evaluation. The effects of variation of the fluid fill level are considered in this research. The trammel pendulum concept is adopted for simulation of fluid movements, known as sloshing, in two articulated tankers of the model. Moreover, a preview driver controller is integrated to the MBD model to provide the follow-up the path during the lane-change and constant radius turn maneuvers. Compared to the results from the simulation of fixed liquid cargo, the critical behavior of the vehicle in terms of rollover at lower speeds is observed when the movement of fluid is taken into account. The results show that transportation of a high density fluid yields a more critical condition compared to a low density one, when the same axle load is retained.
Hazrati Ashtiani, ImanAbedi, Mehrnoosh
Fuel Economy and Emissions Effects of Low Tire Pressure, Open Windows, Roof Top and Hitch-Mounted Cargo, and Trailer2014-01-16144/1/2014
To quantify the fuel economy (FE) effect of some common vehicle accessories or alterations, a compact passenger sedan and a sport utility vehicle (SUV) were subjected to SAE J2263 coastdown procedures. Coastdowns were conducted with low tire pressure, all windows open, with a roof top or hitch-mounted cargo carrier, and with the SUV pulling an enclosed cargo trailer. From these coastdowns, vehicle dynamometer coefficients were developed which enabled the execution of vehicle dynamometer experiments to determine the effect of these changes on vehicle FE and emissions over standard drive cycles and at steady highway speeds. In addition, two minivans were subjected to coastdowns to examine the similarity in derived coefficients for two duplicate vehicles of the same model. The FE penalty associated with the rooftop cargo box mounted on the compact sedan was as high as 25-27% at higher speeds, where the aerodynamic drag is most pronounced. For both vehicles, use of a hitch mounted cargo tray carrying a similar load resulted in very small FE penalties, unlike the rooftop cargo box. The results for the SUV pulling a 3500 pound enclosed cargo trailer were rather dramatic, resulting in FE penalties ranging from 30%, for the city cycle, to 50% at 80 mph, at which point significant CO generation indicated protective enrichment due to high load. Low tire pressure cases resulted in negligible to 10% FE penalty depending on the specific case and test point. Driving with all four windows open decreased FE by 4-8.5% for the compact sedan, and 1-4% for the SUV.
Thomas, JohnHuff, SheanWest, Brian
Trailer Technologies for Increased Heavy-Duty Vehicle Efficiency: Technical, Market, and Policy Considerations2014-01-16224/1/2014
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. In terms of manufacturing and sales, the trailer market is fairly consolidated, with the largest five companies accounting for nearly two-thirds of total sales. The van trailer marker is even more consolidated, with the top five companies making up more than 90 percent of total sales. As policymakers in the United States and across North America weigh options for trailer policy measures, the authors recommend integration of trailers into the Phase 2 U.S. heavy-duty vehicle regulatory program, with emphasis on box trailers but inclusion of other types as well.
Sharpe, Benjamin RodriguezClark, NigelLowell, Dana
NOx Engine Exhaust Emissions Generated from Diesel (CI) Passenger Cars Registered from 2000 to 20122014-01-16204/1/2014
Real world engine emissions measurements were carried out from the University of Antwerp in Belgium and more than 600 passenger cars were measured when entering and leaving two different University campuses. All measurements were done according to the European Commission Directive 2010/48/EU on roadworthiness tests for motor vehicles and their trailers. A database, including a wide variety of vehicles with completely different engine specifications and technological characteristics (engine size, emissions standards exhaust after-treatment devices etc.) has been created and various parameters influencing emissions will be examined. The influence of various parameters on NOx emissions was considered and discussed in this paper. Important conclusions have been made for diesel vehicles and presented in this work. Cold and hot start engine emissions were taken and analyzed in order to determine the percentage that NOx emission increased over the years. A comparison of different generation of cars is also included in the research. Cars' mileage has been considered and divided into two big categories, those with less than 100000 km and the rest with higher mileage. Finally, a comparison between drivers' habits while driving from home to work and different driving styles has been achieved and included in the paper. Some statistical analysis has been also carried out and useful information for local authorities and policy makers can be found in this work. Drivers' age, sex and travelling habits were put together in order to create a database and evaluate them. At the end of this study several suggestions regarding traffic flow and traffic jams are made and should be taken into account by various traffic authorities.
Savvidis, DimitriosBounos, KonstantinosLoakimidis, Christos
Truck Tractor Semitrailer Interchange Coupling DimensionsJ701_201401 (Historical)1/3/2014
The information in this SAE Information Report is the result of studies by the Automobile Manufacturers Association, American Trucking Association, and Truck Trailer Manufacturers Association, to achieve interchangeability of equipment which will comply with the legal dimensional limitations for the majority of states and yet permit increased loading space within these dimensions. This in no way supersedes other information in the SAE Handbook on this subject. Some cases will require more care in application allowing splash shield clearance at trailer support interference points and positioning fifth wheel to allow trailer swing clearance on an 11% grade. All dimensions are given in inches. Table 1 and Figures 1 and 2 show basic requirements for interchangeability of truck tractor and semitrailer equipment. Figure 3 shows the interchangeability of the doubles converter dolly. The formulas for determining LWC, OAL and CFW are: where: FW = fifth wheel advance R = Rear axle tire radius LWC = 90 in = 64 in (short trailers specifically intended for use with two axle tractors) W = 96 in = 102 in C = Clearance, 4 in where: H = Distance from intersection at back of cab and trailer swing radius to top of fifth wheel with zero trailer clearance to first obstruction FWP = Top face of fifth wheel to centerline of pivot, 3.50 in SR = Swing radius of trailer corner
Truck and Bus Total Vehicle Steering Committee
Three Dimensional CFD Analysis on Aerodynamic Drag Reduction of a Bluff Tractor Trailer Body using Vortex Generators2013-01-24589/24/2013
This paper presents a CFD analysis for drag reduction of a Class 8 Tractor-Trailer arrangement. A three dimensional bluff body model of the truck is simulated for a zero degree yaw angle at a speed of 50 miles per hour for a Reynolds Number of 3.3 million. In this paper, the role of vortex generators is investigated for overall drag reduction of the body. The key areas of interest for lowering the drag coefficient are the tractor-trailer gap and the trailer end. The designing of the body was done on DS SolidWorks whereas the CFD simulations were performed on commercial software Ansys Fluent. The Standard k-ε turbulence model was chosen for the simulation while the convergence criterion for the residuals was set at 10−6. The simple bluff body showed a drag coefficient of 1.654. The first design iteration involved increasing the tractor frontal area which resulted in a reduction of 4% in the drag coefficient. Subsequent iterations involved adding vortex generators to the tractor end which resulted in a drag reduction by 4.63%, the trailer end-tractor end combination which reduces the drag coefficient by 6.16% and the tractor-trailer end and trailer base end which records a reduction in drag coefficient by 8.17%. A further reduction of 9.07% is obtained with the addition of 1 vortex generator each to the sides of the trailer end. It can thus be shown that the vortex generators are an effective yet practical solution to address the issue of aerodynamic efficiency for the current commercial trucks without drastically changing the design layout.
Lav, Chitrarth
A New Approach for the Reduction of Aerodynamic Drag of Long-Distance Transportation Vehicles2013-01-24149/24/2013
The optimization of aerodynamic drag represents an important research area for the fuel consumption reduction of heavy duty commercial vehicles. Today's design of tractor-trailers is significantly influenced by legal conditions regarding the vehicle dimensions and the provision of a maximum transportation volume. These boundary conditions lead to brick-shaped trailer outer geometries, especially at the rear ends. That is the reason why the investigations of aerodynamic optimization of commercial vehicle trailers are predominantly restricted to detail measures up to now. The present publication treats the aerodynamic characteristics of general modifications on the outer contour of long-distance haulage trailers in regard of reducing the drag resistance and, thus, potentially also the fuel consumption in highway traffic. A new approach for the realization of a variable outer contour of trailers provides the possibility to adjust the rear end to an aerodynamically optimized shape. The variable adjustment of the sidewalls and the top of the trailer's rear end can take the actual space requirements of the transportation load into account; by this an optimal transportation efficiency is guaranteed. The research work is based on a generic, virtual 3D-CAD semi-trailer truck, which displays the characteristics of commercial vehicles and serves as a basis for several modifications. All geometrical modifications at the virtual reference vehicle are investigated and assessed by 3D-computational fluid dynamics simulations. The achieved reduction of drag leads to a decrease of fuel consumption, which encloses both, optimized operating costs for carriers as well as reduced CO2 emissions which support the intentions of environmentally friendly road transport.
Hirz, MarioStadler, Severin
Considerations for the Wind Tunnel Simulation of Tractor-Trailer Combinations: Correlation of Full- and Half-Scale Measurements2013-01-24569/24/2013
The 9-meter wind tunnel of the National Research Council (NRC) of Canada is commonly employed in testing of class 8 tractors at full- and model-scales. In support of this work a series of tests of an identical model at full- and half-scale were performed to investigate some of the effects resulting from simulation compromises. Minimum Reynolds Number considerations drive the crucial decisions of what scale and speed to employ for testing. The full- and half-scale campaigns included Reynolds Number sweeps allowing conclusions to be reached on the minimum Reynolds number required for testing of fully-detailed commercial truck models. Furthermore the Reynolds sweeps were repeated at a variety of yaw angles to examine whether the minimum Reynolds Number was a function of yaw angle and the resulting flow regime changes. The test section of the NRC 9-meter wind tunnel is not sufficiently long to accommodate a full-scale tractor and a typical trailer length of 48′ or more. Most of full-scale testing is therefore conducted with a more manageable 28′ trailer. To quantify the effects of this simplification the half-scale model was tested with representations of 28′ and 48′ trailers. The changes in the baseline drag curves will be presented along with the effect of trailer devices, such as skirts, on the different lengths of trailer.
Leuschen, Jason
Regulatory Options for Improving Aerodynamic Performance of Commercial Vehicles2013-01-24169/24/2013
This paper examines how commercial vehicle aerodynamic improvements can be influenced by regulation particularly with respect to size and weight policy. It discusses the potential use of performance based standards (PBS) first introduced to optimize vehicle configurations in terms of vehicle stability and control and compatibility with highway geometry. There are several vehicle treatments that can be used to reduce aerodynamic drag, some of which lengthen or widen the vehicle without increasing cargo capacity. One such solution is referred to as ‘boat tails” consisting of a light weight external extension of the trailer allowing the air flow to remain attached as the vehicle cross section diminishes resulting in a reduction in the area of negative pressure at the end of the vehicle which reduces drag force. Aerodynamic treatments of this type extend the length of the vehicle in the order of 30 to 60 cm which will contravene prescriptive size and weight regulations unless regulatory flexibility can be introduced to accommodate such innovation. There are other aerodynamic treatments which may alter classic vehicle design and form in a way that may violate prescriptive regulations. For example in Europe there are limited options for truck manufactures to include front end aerodynamic treatments given regulated length constraints. This paper will discuss regulatory measures being developed in Europe and the potential for the use of PBS to support aerodynamic innovation.
Woodrooffe, JohnDahlberg, Erik
A Gain-Scheduled PID Controller for Automatic Path Following of a Tractor Semi-Trailer2013-01-06874/8/2013
Improving driving safety and freeway capacity is an indispensable research issue for road vehicles, especially for tractor semi-trailers, which on the one hand exhibit unstable motion modes at high speeds due to their articulated configurations and undertake the largest part of freight transportation on freeways. Automatic driving is rated as the ultimate solution of vehicle safety since it can significantly reduce accidents resulting from human driver errors. Proposed in this paper is a gain-scheduled PID controller for automatic path-following of a tractor semi-trailer. The PID controller minimizes the vehicle's predicted lateral deviation and heading error with respect to the desired path at a preview point, and gains of the controller are scheduled with respect to vehicle speed. The gains of the controller at several given vehicle speeds are tuned using the orthogonal experimental design method (OEDM), based on comprehensive evaluation of lateral path deviation, steering angle input and vehicle stability index under a double lane change maneuver. The tuned gains are further fitted using linear and quadratic functions to form a gain-scheduled control system. The controller is evaluated by simulations using a high-fidelity nonlinear tractor semi-trailer model built in the TruckSim software. Simulation results show that the automatic path following controller can control the tractor semi-trailer to follow the desired path with quite small tracking errors and keep the vehicle stable at various vehicle speeds and road friction conditions with a reasonable steering input.
Ding, NenggenZhang, YipengGao, FengXu, Guoyan
Numerical Simulation of the Transient Heat-Up of a Passenger Vehicle during a Trailer Towing Uphill Drive2013-01-08734/8/2013
In the digital prototype development process of a new Mercedes-Benz, thermal protection is an important task that has to be fulfilled. In the early stages of development, numerical methods are used to detect thermal hotspots in order to protect temperature sensitive parts. These methods involve transient full Vehicle Thermal Management (VTM) simulations to predict dynamic vehicle heat-up during critical load cases. In order to simulate thermal control mechanisms, a coupled 1D to 3D thermal vehicle model is built in which the coolant and oil circuit of the engine, as well as the exhaust flow are captured in detail. When performing a transient 3D VTM analysis, the conduction and radiation phenomena are simulated using a transient structure model while the convective phenomena are co-simulated in a steady state fluid model. Both models are brought to interaction at predetermined points by an automatized coupling method. In addition, a 1D transient vehicle analysis is used to provide transient boundary conditions for the 3-dimensional vehicle. This 1D analysis provides the inputs for the cooling system, exhaust system, oil circuit, and the heat release inside of the engine combustion chamber. As a first step a computation of the heat-up during a trailer towing uphill drive at 35 km/h is performed and validated with experimental data. For this purpose, extensive heat-up measurements are conducted in a climatic wind tunnel. The car was preconditioned at 30°C and at the end of the test all relevant components reached a constant temperature. Comparing simulation results of the transient heat-up with measurement, the computational methodology is yielding to an encouraging agreement; especially for temperature-sensitive components like the engine mounts and actuators next to the turbocharger. In conclusion, it can be said that transient numerical coupling methods are capable of simulating the heat-up of the engine, the exhaust system, and temperature-sensitive parts in the underhood. In particular, detailed flow modeling of the exhaust flow and the coolant and oil circuit is the major key. Especially the surrounded parts in the engine compartment can be fairly good simulated according to measurements in the climatic wind tunnel.
Disch, MarioWiddecke, NilsWiedemann, JochenReister, HeinrichWeidmann, Ernst Peter
Items per page:
1 – 50 of 267