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Viewing 31 to 60 of 7721
2018-04-03
Technical Paper
2018-01-0233
Scott Skeen, Koji Yasutomi, Emre Cenker, Brian Adamson, Nils Hansen, Lyle Pickett
The formation of soot in high-pressure sprays of n-dodecane is visualized and quantified under conditions relevant to heavy-duty diesel engines. Sprays are injected from a single-hole diesel injector belonging to the family of Engine Combustion Network (ECN) Spray D injectors. Soot optical thickness (KL) and the total soot mass are quantified using a high-speed extinction imaging diagnostic with incident light wavelengths of 632 nm and 850 nm. The total soot mass is derived from KL using a non-dimensional extinction coefficient based on the Rayleigh-Debye-Gans approximation for fractal aggregates (RDG-FA). Previous work showed consistency between the total soot mass measured with incident wavelengths of 406 nm, 520 nm, and 632 nm; however, the present work demonstrates a significant difference for measurements with incident light in the infrared.
2018-04-03
Technical Paper
2018-01-0237
Ryan Vojtech
For internal combustion engines, the compression ratio (r) is defined as the ratio of volume at bottom dead center to the volume at top dead center and is a fundamental design parameter influencing the thermodynamic operation of the modern combustion engine. Thermodynamic cycle analysis can show that the cycle thermal efficiency increases as the compression ratio increases. An increase in the compression ratio changes the cycle such that peak compression pressure and temperatures are increased resulting in subsequent increases in the peak combustion pressure and temperature. Since the average temperature of heat addition is increased in the cycle, the thermal efficiency would theoretically increase as long as both cycles had the same heat rejection processes. These changes in peak pressure and temperature of the cycle must also be evaluated in terms of anticipated increases in engine friction and changes to the combustion duration respectively.
2018-04-03
Technical Paper
2018-01-0284
Shane Daly, Emre Cenker, Lyle Pickett, Scott Skeen
This work investigates the impact of injector temperature on the characteristics of high-pressure n-dodecane sprays under conditions relevant to heavy-duty diesel engines. Sprays are injected from a pair of single-hole diesel injectors belonging to the family of “Spray C” and “Spray D” Engine Combustion Network (ECN) injectors. Low and high injector temperature conditions are achieved by activating or de-activating a cooling jacket. We quantify spray spreading angle and penetration using high-speed shadowgraph and long-distance-microscopy imaging. We evaluate differences in fuel/air mixture formation at key timings through one-dimensional modeling. Injections from a cooled injector penetrate faster than those from a higher temperature injector, especially for an injector already prone to cavitate (Spray C).
2018-04-03
Technical Paper
2018-01-0259
Michael Saccullo, Timothy Benham PhD, Ingemar Denbratt
Laws concerning emissions from heavy duty (HD) internal combustion engines are becoming increasingly stringent. New engine technologies are therefore needed to satisfy these new legal requirements and to reduce fossil fuel dependency. One way to achieve both goals is to partially replace fossil fuels with alternatives that are more sustainable with respect to emissions of greenhouse gas, particulates and NOx. Therefore a dual fuel direct injection HD engine using ethanol or methanol as the main fuel with a pilot diesel injection to facilitate ignition was studied. The objective of this investigation was to find practical ways of combining the established advantages of Diesel engines, such as high fuel efficiency, with the advantages of alcohol fuels such as lower particulate emissions, bypassing the NOx-soot-trade-off. Furthermore, this study serves as a proof-of-concept, demonstrating that methanol and ethanol can successfully be used in a high pressure Diesel injection system.
2018-04-03
Technical Paper
2018-01-0362
Imad A. Khalek, Huzeifa Badshah, Vinay Premnath, Rasto Brezny
Solid particle number emissions above and below 23 nm were investigated for a state-of-the-art stoichiometric heavy-duty natural gas engine with a three-way-catalyst and a diesel heavy-duty diesel engine with DFP. Furthermore, real time ash particle number emissions were measured using SwRI real time ash measurement instrument (RT-ASH). Both engines met the potential future CARB ultra low NOX emissions of 0.02 g/hp-hr, a 90% reduction from current emissions level in the USA. The engines were tested in an engine test cell under cold- and hot-start transient engine operation including FTP, WHTC and RMC. While both engines met comfortably the PM mass emissions, solid particle number emissions and ash emissions were significant for the natural gas engine. The emissions of solid particles from the natural gas was a factor of 5 to 10 higher than that of a diesel engine with DPF.
2018-04-03
Technical Paper
2018-01-0381
Devin Batcheller, Kody Taylor
A new compression release engine brake system has been developed which utilizes the well-known lost motion idea along with an entirely new valve resetting mechanism. The engine brake is fully integrated into the exhaust rocker arm, making it one of the most compact solutions on the market. The novel reset mechanism provides a pressure sensing reset timing which optimizes engine brake performance and valve train stress at all engine speeds. Hydraulic system simulation studies were performed to first verify the concept on paper. Once acceptable performance was predicted, physical prototypes were produced. The Cummins ISL 8.9L engine was chosen as a proof of concept platform due to its availability in the North American market and its factory engine brake option. The factory engine brake gives a data set for comparison while validating this new technology. All targets for engine brake function were achieved, and a substantial increase in performance was demonstrated.
2018-04-03
Technical Paper
2018-01-0394
MahendraMohan Rajagopal
Current developments in tractor transmission design has galloped to new heights with the introduction of CVT, Power shift, Power shuttle, hydrostatic etc besides the vastly available synchromesh and constant-mesh gearboxes. In contrary to the above existing facts of new powertrain development, there is a definite market need to revamp the heritage tractor models to be equipped with the modern transmission systems. This will help the customers have the advanced drivetrain features in these legacy tractors that have won many hearts. One such modernization was the development of new power shuttle transmission in legacy tractor models for TAFE tractors. Power shuttle primarily enables a tractor - in this case, to go forward and reverse by operating a wet clutch without human intervention. A flick of lever, usually on the steering column changes the direction of the tractor at the same speed of the gear selected.
2018-04-03
Technical Paper
2018-01-0390
MahendraMohan Rajagopal
Recently, emerging technological developments in powertrain were mostly accompanied with electronics for efficient and precise control of powertrain system. Agricultural tractors are of no exception to this context. Most of the higher horsepower tractors above 50 HP are equipped with modern transmission systems such as Power-shuttle, Power-shift etc. having their wet clutch transmission and diesel engine controlled by an Electronic Control Unit. This is possible only with an engine that receives and provides electronic signals. Whereas a tractor with mechanical (non-electronic) engine is of predominant use in the Indian farm lands due to their low cost and immediate availability compared to that of an engine equipped with hi-fi electronics. Hence, there is a demand for low cost drivetrain with improved controls and without engine electronics.
2018-04-03
Technical Paper
2018-01-0303
Roberto Torelli, Katarzyna E. Matusik, Kyle C. Nelli, Alan L. Kastengren, Kamel Fezzaa, Christopher F. Powell, Sibendu Som, Yuanjiang Pei, Tom Tzanetakis, Yu Zhang, Michael Traver, David J. Cleary
Cyclic variability in internal combustion engines arises from multiple concurrent sources, many of which remain to be fully understood and controlled. This variability can, in turn, affect the behavior of the engine resulting in undesirable deviations from the expected operating conditions and performance. Shot-to-shot variation during the fuel injection process is strongly suspected of being a source of cyclic variability. This study focuses on the shot-to-shot variability of injector needle motion and its influence on the internal nozzle flow behavior using diesel fuel. High-speed x-ray imaging techniques have been used to extract high-resolution injector geometry images of the sac, orifices, and needle tip that allowed the true dynamics of the needle motion to emerge. These measurements showed high repeatability in the needle lift profile across multiple injection events, while the needle radial displacement was characterized by a much higher degree of randomness.
2018-04-03
Technical Paper
2018-01-0338
Yunhua Zhang, Diming Lou, Piqiang Tan, Zhiyuan Hu
The increasingly stringent emission regulations have mandated the use of CCRT (Catalyzed Continuously Regeneration Trap) made by upstream DOC (diesel oxidation catalyst) and downstream CDPF (catalyzed diesel particulate filter) for heavy-duty diesel vehicles, which is proved to be the only way that can efficiently control the gaseous and particulate emissions. The performance of after-treatment is greatly influenced by the running conditions of the diesel vehicle and its exhaust parameters, so this paper intended to use grey relational analysis to study the correlation between running conditions such as velocity, acceleration and VSP (Vehicle Specific Power), exhaust parameters including exhaust flow, DOC inlet temperature, and concentrations of CO, THC, O2 and NOX of an urban bus and the performances of DOC and CCRT based on chassis dynamometer.
2018-04-03
Technical Paper
2018-01-0348
Matthias Schwelberger, Barouch Giechaskiel, Achim Dittler
The European Commission plans to introduce a (solid) particle number (PN) emissions limit for type approval and in-service conformity (ISC) by the end of 2018 (Euro VI d) using PEMS (Portable Emission Measurement System) tests on heavy duty vehicles on the road. Till today performance, measurement accuracy and sensitivity of several on-board particle counters for heavy duty applications haven’t been tested in parallel. Our investigations have been conducted on a chassis dyno with and Euro VI vehicle (N3-class vehicle, 12.8 l, Euro VI) with DOC (Diesel Oxidation Catalyst), DPF (Diesel Particle Filter), SCR (Selective Catalytic Reduction) and ASC (Ammonia Slip Cat). The PN-PEMS examined were based on two different counting technologies: CPC (Condensation Particle Counter) and DC (Diffusion Charger).
2018-04-03
Technical Paper
2018-01-0657
Andrei Izmailov, Alexandr Lavrov, Zakhid Godzhaev, Vladimir Shevtsov, Valeriya Zubina
Existing methods of assessing the technical level, both in Russia and abroad, are associated with an expert approach that is limited by the qualitative nature of the conclusions, which does not allow predicting a quantitative change in performance. In this regard, if there are up to 35 models on the Russian market with equal power capabilities, the problem of specifying the choice arises. The article considers a new technique for assessing the technical level of agricultural tractors competing in one power range. A general indicator of the technical level is the ratio of the replacement capacity of the arable unit based on the tractor model under consideration to the replacement capacity of the arable unit based on the reference tractor, which are determined by computer simulation in reference conditions.
2018-04-03
Technical Paper
2018-01-0638
Sauhard Singh, S K Mishra, V K Bathla, Reji Mathai, Shyam Singh, Deepak saxena, SSV Ramakumar, G Senthilkumar, M Sathyanandan, P Mahesh
To address the twin challenge of energy security and environment issues arises due to extensive use of fossil fuels, it is felt necessary worldwide to embark upon alternative fuels to diversify the energy basket with due consideration of environment. Various alternative fuels like natural gas, bio-fuels, methanol, ethanol, DME etc. are under consideration with various degree of research work carried out on these alternatives worldwide and at various stages of implementation with country specific requirement and availability scenario. Natural gas has been considered and implemented as alternative fuel to gasoline and diesel powered vehicles worldwide. Although natural gas belongs to petroleum fuel family, it has considerable recourses worldwide to ensure long energy security and comparatively lower carbon to hydrogen ratio that make it more environment friendly. In line with worldwide trend, India also focused on CNG powered vehicles specifically on metropolitan city transport buses.
2018-04-03
Technical Paper
2018-01-0632
Michael Gross, Ahmet Mazacioglu, Justin Kern, Volker Sick
Optical imaging diagnostics of combustion are most often performed in the visible and near-ultraviolet spectral regions, in part because camera technology is most mature in these bands, but operating in the infrared (IR) provides a number of benefits. These benefits include access to emission lines of relevant chemical species (e.g. water, carbon dioxide, and carbon monoxide) and obviation of intensifiers (thus avoiding reduced spatial resolution and increased cost). High-speed IR in-cylinder imaging and extensive post-processing were used to investigate the relationships between infrared images, quantitative image-derived metrics (e.g. location of the flame centroid), and measurements made with in-cylinder pressure transducers (e.g. coefficient of variation of mean effective pressure). A Weichai 9.7-liter, inline-six, natural-gas-fueled engine was modified to enable exhaust-gas recirculation and to provide borescopic optical access to one cylinder for two Xenics cameras.
2018-04-03
Technical Paper
2018-01-0510
R. Michael Van Auken, John Lenkeit, Terrance Smith
Advanced Crash Avoidance Technologies (ACATs) such as Forward Collision Warning (FCW) and Automatic Emergency Braking (AEB) have been developed for light passenger vehicles (LPVs) to avoid and mitigate collisions with other road users and objects. However the number of motorcycle (MC) crashes, injuries, and fatalities in the United States has remained relatively constant. To fully realize potential safety benefits, advanced driver assistance systems and future automated vehicle technologies also need to be effective in avoiding collisions with motorcycles. Towards this goal the Honda-DRI ACAT Safety Impact Methodology (SIM), which was previously developed to evaluate LPV ACAT system effectiveness in avoiding and mitigating collisions with fixed objects, other LPVs, and pedestrians, is being extended to also evaluate the effectiveness of ACATs in avoiding and mitigating LPV-MC collisions.
2018-04-03
Technical Paper
2018-01-0527
Jay Przybyla, Thomas Rush, Kelly Palframan, Daniel Melcher
A high rate of traffic collisions occur at signalized intersections. The use of historical and static traffic signal timing data in conjunction with witness testimony has typically been used to assist accident reconstructionists in determining the status of a traffic signal leading up to and at the time of a collision. Recent technological advancements in signal timing data collection, recording, and logging can provide accident reconstructionists with a new and more robust method of analyzing signalized intersection collisions. This paper presents the history and current state of signal of the art for traffic signalization; Signal Timing Data Loggers. We also present how to obtain, analyze, and interpret the data logger data and possible applications of such to accident reconstruction.
2018-04-03
Technical Paper
2018-01-0528
Terry D. Day
On-highway heavy trucks are using air disc brakes with increasing frequency. Disc brakes and traditional air drum brakes have different characteristics when it comes to brake adjustment and heat dissipation. These differences lead to different failure modes when overheated. This paper describes how adjustment affects the general braking capability of on-highway trucks fitted with disc and drum brakes. A loaded truck on a long, down-hill grade is used to illustrate how brake temperature increases over time, and how that temperature increase can result in a runaway condition. A “virtual” truck fitted with both traditional drum brakes and new disc brakes is used to illustrate operational differences between the two brake types.
2018-04-03
Technical Paper
2018-01-0532
Emmanuel Jay Manuel, Richard Mink, Daniel Kruger
As part of an accident reconstruction, vehicle speeds and positions are usually always of interest. When provided scene photographs or fixed video surveillance footage of the crash itself, close-range photogrammetry methods can be useful in determining the placement of physical evidence, vehicle speeds and positions. Available 3D modeling software can also be used by way of virtually matching photographs or fixed video surveillance footage. Dash or vehicle mounted camera systems are being used in light vehicles, commercial vehicles and locomotives. Suppose video footage from a dash camera mounted to one of the vehicles involved in the accident is provided for an accident reconstruction and EDR data is unavailable for the either vehicles involved. The literature to date describes using still photos to locate fixed objects, using video taken from stationary locations to determine the speed of moving objects and using video taken from a moving vehicle to locate fixed objects.
2018-04-03
Technical Paper
2018-01-0747
Douglas Tyler Landfried, David Alex, Andrew Mosedale
Despite the recent broadening of acceptable test methods for certifying aerodynamic performance, there has been little attention on how to determine the time averaging window used for providing mean forces. This is of particular relevance to the assessment of commercial vehicles as they are significantly affected by low-frequency patterns that are hard to predict and vary with different geometry configurations. Published guidelines in the industry suggest that good engineering judgement be used and a qualitative assessment of force histories is adequate. These suggested methods leave the accuracy of the time averaging to the experience and judgement of the user and is highly dependent on the specific characteristics of the benchmark case. Furthermore these methods are not able to quantify the error present due to motions slower than length of the sampled data.
2018-04-03
Technical Paper
2018-01-0732
Kambiz Salari, Jason Ortega
Lawrence Livermore National Laboratory (LLNL) has been funded by Department of Energy (DOE)/Office of Energy Efficiency and Renewable Energy (EERE)/Vehicle Technology Office to conduct series of scaled wind tunnel test to investigate the aerodynamic benefits of heavy vehicle platooning. In 2015 and 2016 LLNL has conducted platooning experiments using Army’s 7’x10’ wind tunnel located at NASA Ames Research Facility. For these tests, LLNL has designed and fabricated a wind tunnel platform to test truck platoons up to three vehicle configurations with the maximum vehicle separation distance of 320 feet full-scale. This unique platform accounts for the crosswind effects on the drag force and cooling air supply for yaw angles ranging from -15 to 15 degrees. The pressure measurements for all vehicles are taken at mid-grille height. Particle Image Velocimetry (PIV), a type of instantaneous flow visualization, is used to probe the physics involved.
2018-04-03
Technical Paper
2018-01-0707
Mohamed Ibrahim
It is well known that the underbody region of a tractor-trailer is responsible for up to 30% of the aerodynamic drag. This is the highest drag created by any region of a tractor-trailer. There are a number of underbody drag-reduction devices available on the market but they create a few operational issues, such as low ground clearance and ice collection, which inhibit their mass market appeal. In this paper, a novel concept of an underbody aerodynamic device is developed and investigated. The underbody device is a combination of a ramp and a side skirt; which were optimized simultaneously at different angles. In addition, the device is made collapsible to facilitate easy storage when not in use (i.e., city driving). NASA’s Generic Conventional Model (GCM); a 1:8 scale model of a generic class-8 tractor-trailer is being used to evaluate and optimize the concept. The GCM allows the concept to be applicable to a wider range of tractor-trailers.
2018-04-03
Technical Paper
2018-01-0708
Huadong Yao, Zenitha Chroneer, Lars Davidson
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 detached eddy simulation (DES) approach. The truck configuration consists of a compartment and trailer. Due to the large size of the truck and the complexity of the geometry, some simplifications are applied in the simulation. A purpose of this work is to investigate whether the simplifications are valid to obtain the reasonable properties of the flow near the mirror. A simplification is to use the symmetric boundary condition on the symmetry plane of the truck configuration. Half of the configuration is therefore simulated. The computational results with this half configuration are compared with those with the entire configuration. Furthermore, the configuration is simplified in two ways. The first way is to remain the key exterior components of the truck body while removing the small gaps and structures.
2018-04-03
Technical Paper
2018-01-0714
Isabel Vallina Garcia, Holger Babinsky
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. This study investigates the impact of underbody roughness, which simulates the standard blockage caused by typical underbody components, on the wake structure. This work uses a simple 1/10th scale model with the geometry and aspect ratio of a generic HGV. A roughness pattern is attached to the underbody of the model and compared to a smooth configuration. Testing is conducted in a water towing tank, which establishes correct ground conditions. The facility operates at Reynolds Numbers of approximately Re = 690000. Optical access into the underbody and the near wake is possible through the clear working section of the facility.
2018-04-03
Technical Paper
2018-01-0888
Daniel cohn, Leslie Bromberg
Long-haul heavy-duty engines, presently almost entirely powered by diesel fuel, face challenges in meeting the worldwide need for greatly reducing their nitrogen oxides (NOx) emissions. These emissions produce smog and create respiratory problems. There is also a need to reduce greenhouse gas emissions. Dual-fuel gasoline-alcohol engine technology can provide a means to meet this need at an affordable cost. The engine could provide operation a wide fuel range from mainly gasoline use to 100% alcohol use. Use of stoichiometric operation and a three way catalytic converter can reduce NOx by around 90% relative to emissions from diesels with state of the art exhaust treatment. The alcohol fuel provides increased knock resistance, enabling high compression ratio, turbocharged operation that provides comparable efficiency and torque to a diesel engine. The alcohol can be ethanol or methanol and can be neat or a high concentration blend.
2018-04-03
Technical Paper
2018-01-0898
Jordan Paz, Dan Staaden, Sage Kokjohn
Engine experiments were carried out on a heavy-duty single-cylinder engine to investigate the effects of post injections on soot production. In this context, the term “post injection” refers to an injection shortly after the main, near firing Top Dead Center (TDC) injection. Both high load Gasoline Compression Ignition (GCI) post injection experiments and Conventional Diesel Combustion (CDC) post injection experiments were run. Load ranged from 16 – 21.5 bar gross Indicated Mean Effective Pressure (IMEPg) with the post injections extending the load up to 35%. Three post injection timings were used between 12 – 40 dATDC; at each injection timing, every load, and with both fuels, there was no soot benefit seen from using a post injection. This result was contradictory to what is seen in literature at low to mid load conditions. Thus, experiments were run at low to mid load, replicating conditions found in literature.
2018-04-03
Technical Paper
2018-01-0904
Zhenkan Wang, Panagiota Stamatoglou, Marcus Lundgren, Ludovica luise, Bianca Maria Vaglieco, Arne Andersson, Oivind Andersson, Marcus Alden, Mattias Richter
In order to meet the requirement on the stringent emission regulations recently, more and more research works have been focused on homogeneous charge compression ignition (HCCI) and partially premixed combustion (PPC) or partially premixed compression ignition (PCCI) as they have the potentials to produce low NOx and soot emissions without adverse effects on engine efficiency. The mixture formation and stratification charge largely influence the combustion behavior and emissions for PPC/PCCI. An ultra-high speed burst mode laser is used to capture the mixture formation process from the start of injection until several CADs after start of combustion in a single cycle. To the authors’ best knowledge, this is the first time that such a high temporal resolution, i.e. 0.2 CAD, PLIF could be accomplished for imaging of the in-cylinder mixing process. The capability of resolving single cycles allows for the influence of cycle-to-cycle variations to be eliminated.
2018-04-03
Technical Paper
2018-01-0870
Anton D. Sediako, Jelena Andric, Jonas Sjoblom, Ethan Faghani
In order to meet emissions and power requirements, modern engine design has evolved in complexity and control. The cost and time restraints of calibration and testing of various control strategies have made virtual testing environments increasingly popular. Using Hardware-in-the-Loop (HiL), Volvo Penta has built a virtual test rig named VIRTEC for efficient engine testing, using a model simulating a fully instrumented engine. This paper presents an novel Artificial Neural Network (ANN) based model for engine simulations in a HiL environment. The engine model, herein called Artificial Neural Network Engine (ANN-E), was built for a D8-600 hp Volvo Penta engine, and directly implemented in the VIRTEC system. ANN-E uses a combination of feedforward and recursive ANNs, processing 7 actuator signals from the engine management system (EMS) to provide 30 output signals.
2018-04-03
Technical Paper
2018-01-0824
Bing Zhu, Yao Feng, Jian Zhao
Since the traffic accidents involving tractor-semitrailer usually lead to serious consequences, the active braking system for tractor-semitrailer becomes the research hotspot. In this paper, a set of active pneumatic braking system was designed based on the novel pneumatic braking system of tractor-semitrailer, which can realize the active braking of the vehicle under emergency conditions. A test bench of the active braking system has been build, based on which the typical characteristics of the active braking system were tested, and a precise mathematic model of the active pneumatic braking system were established, and then the model has been modified by the experimental data got from the test bench. Based on the model, the control strategy of the active pneumatic braking system was designed, and it was validated by the test bench. The test results showed that the control strategy of the active pneumatic braking system can precisely control the braking pressure of the vehicle.
2018-04-03
Technical Paper
2018-01-0825
Tianqi Lv, Yunqing Zhang
The measurement and analysis of vehicle suspension kinematics and compliance (K&C) play an important role in the vehicle handling and stability. At present, K&C test rig measurement system use contact-type method, but it has the shortcomings of inefficiency and low test accuracy. In this paper, a description of the measurement system, including layout, instrumentation, actuators, and controls is presented. A new non-contact measurement method based on binocular vision measurement system is proposed to achieve fast and accurate measurement of wheel alignment parameters, and the solution algorithm for calculating the K&C characteristic parameters is deduced. A multi-body dynamics software is used to create a rigid axle suspension model and the K&C test rig model. The multi-body model is used to verify the accuracy of the measure method and solution algorithm.
2018-04-03
Technical Paper
2018-01-0797
Michael Siemon, Patrick Smith, Dudley Nichols, David Bevly, Scott Heim
A Computational Fluid Dynamics (CFD) study was conducted on four-vehicle platoons, and the aerodynamic data is then coupled with a high-fidelity truck simulation software (TruckSim) to determine fuel efficiency. Previous studies typically have focused on identical two vehicle platoons, whereas this study accounted for more complex platoon configurations. Heavy duty vehicles (HDVs), both military and commercial, make up a significant percentage of fuel consumption. This study aimed to quantify fuel savings of a platoon consisting of dissimilar trucks and trailers, thus reducing vehicle operational cost. The vehicle platoon featured two M915 trucks and two Peterbilt 579 trucks with dissimilar trailer configurations. An unloaded flatbed trailer, a centered 20 ft shipping container, two 20 ft shipping containers, and a 53 ft box trailer configurations were utilized.
Viewing 31 to 60 of 7721