Criteria

Display:

Results

Viewing 211 to 240 of 7720
2017-03-28
Technical Paper
2017-01-0696
Yu Zhang, Steven Sommers, Yuanjiang Pei, Praveen Kumar, Alexander Voice, Michael Traver, David Cleary
Abstract This research investigates the combustion characteristics and engine performance of a conventional non-ethanol gasoline with a research octane number of 91(RON 91) and a higher reactivity RON80 gasoline under mixing-controlled combustion. The work was conducted in a model year 2013 Cummins ISX15 heavy-duty diesel engine. A split fuel injection strategy was developed to address the long ignition delay and high maximum pressure rise rate for the two gasoline fuels. Using the split fuel injection strategy, steady-state NOx sweeps were conducted at 1375 rpm with a load sweep from 5 to 15 bar BMEP. At 5 and 10 bar BMEP, both gasolines consistently exhibited lower soot levels than ULSD with the reduction more pronounced at 5 bar BMEP. 3-D CFD combustion simulation suggested that the higher volatility and lower viscosity of gasoline fuels can help improve the in-cylinder air utilization and therefore reduce the presence of fuel-rich regions in the combustion chamber.
2017-03-28
Journal Article
2017-01-0703
Chad Koci, Adam Dempsey, Jeffery Nudd, Bradley Knier
Abstract Fundamental understanding of the sources of fuel-derived Unburned Hydrocarbon (UHC) emissions in heavy duty diesel engines is a key piece of knowledge that impacts engine combustion system development. Current emissions regulations for hydrocarbons can be difficult to meet in-cylinder and thus after treatment technologies such as oxidation catalysts are typically used, which can be costly. In this work, Computational Fluid Dynamics (CFD) simulations are combined with engine experiments in an effort to build an understanding of hydrocarbon sources. In the experiments, the combustion system design was varied through injector style, injector rate shape, combustion chamber geometry, and calibration, to study the impact on UHC emissions from mixing-controlled diesel combustion.
2017-03-28
Journal Article
2017-01-0705
Jost Weber, Olaf Herrmann, Ron Puts, Jyun Kawamura, Yasufumi Tomida, Makoto Mashida
Abstract Future diesel engine legislation Tier 4 / Stage V and EU6d demand further improvements to reduce CO2 while keeping the already low NOx emissions levels. For US trucks a more strict limit of 0.2 g/bhp-hr NOx emissions need to be achieved. In this trade-off, system costs and complexity of the after-treatment are defining the constraint in which the common rail fuel injection system layout has to be defined. The increase of rail pressure was in the past the major step to control the soot emissions in view of low engine-out NOx emissions by applying massive EGR. With the on-going development of NOx-aftertreatment by Selective Catalytic Reduction (SCR), conversion efficiencies of up to 97% allow to reduce the EGR usage and rail pressure usage. In that context, the steepness of injection rate, the nozzle flow rate and the injection pressure are remaining parameters to control the NOx emissions.
2017-03-28
Technical Paper
2017-01-0708
Carlos Jorques Moreno, Ola Stenlaas, Per Tunestal
Abstract Factors influencing the effect of pilot-injection on main-injection combustion were investigated using heat release analysis in a heavy-duty diesel engine fuelled with standard diesel fuel, and included the effect of those factors on engine performance and emissions. Combinations of pilot injection parameters i.e. pilot start of injection, pilot mass, pilot-main injection separation, and rail pressure were studied for various operating conditions and combustion phases. It was concluded that the effect of pilot-injection combustion on main injection can be studied based on the phase of pilot combustion at the start of main injection. Four cases were identified: a) main injection during the mixing phase of pilot injection; b) main injection during the premixed phase of pilot combustion; c) main injection during the diffusive phase of pilot combustion and d) main injection after pilot combustion was completed.
2017-03-28
Journal Article
2017-01-0723
Jacqueline O'Connor, Meghan Borz, Daniel Ruth, Jun Han, Chandan Paul, Abdurrahman Imren, Daniel Haworth, Jonathan Martin, Andre Boehman, Jian Li, Kevin Heffelfinger, Samuel McLaughlin, Richard Morton, Arne Andersson, Anders Karlsson
Abstract This paper describes a novel design and verification process for analytical methods used in the development of advanced combustion strategies in internal combustion engines (ICE). The objective was to improve brake thermal efficiency (BTE) as part of the US Department of Energy SuperTruck program. The tools and methods herein discussed consider spray formation and injection schedule along with piston bowl design to optimize combustion efficiency, air utilization, heat transfer, emission, and BTE. The methodology uses a suite of tools to optimize engine performance, including 1D engine simulation, high-fidelity CFD, and lab-scale fluid mechanic experiments. First, a wide range of engine operating conditions are analyzed using 1-D engine simulations in GT Power to thoroughly define a baseline for the chosen advanced engine concept; secondly, an optimization and down-select step is completed where further improvements in engine geometries and spray configurations are considered.
2017-03-28
Journal Article
2017-01-1554
Ajith Jogi, Sujatha Chandramohan
Abstract Over the years, commercial vehicles, especially tractor-semitrailer combinations have become larger and longer. With the increasing demand for their accessibility in remote locations, these vehicles face the problem of off-tracking, which is the ensuing difference in path radii between the front and rear axles of a vehicle as it maneuvers a turn. Apart from steering the rear axle of the semitrailer, one of the feasible ways of mitigating off-tracking is to shift the fifth wheel coupling rearwards. However, this is limited by the distribution of the semitrailer’s load between the two axles of the tractor; any rearward shift of the fifth wheel coupling results in the reduction of the total static load on the tractor’s front axle and hence available traction. This may in turn lead to directional instability of the vehicle. In the present work, a new model of the fifth wheel coupling is proposed which the authors call Split fifth wheel coupling (SFWC).
2017-03-28
Technical Paper
2017-01-1579
Liang-kuang Chen, Chien-An Chen
Abstract The development of an integrated controller for a 4WS/4WD electric bus is investigated. The front wheel steering angle is assumed to be controlled by the human driver. The vehicle is controlled by the rear wheel steering and the yaw moment that can be generated by the differential torque/brake control on each wheel. The high speed cornering is used as the testing scenario to validate the designed controller. Due to the highly nonlinear and the multiple-input and multiple-output nature, the control design is separated into different stages using the hierarchical layer control concept. The longitudinal speed is controlled using a PI controller together with a rule-based speed modification. The other two control inputs, namely the rear wheel steering and the DYC moment, are then designed using the state-dependent Riccati equation method. The designed controllers are evaluated using computer simulations first, and the simulations showed promising results.
2017-03-28
Technical Paper
2017-01-1575
Andrei Keller, Sergei Aliukov, Vladislav Anchukov
Abstract Trucks are one of the most common modes of transport and they are operated in various road conditions. As a rule, all-wheel drive trucks are equipped with special systems and mechanisms to improve their off-road capability and overall efficiency. The usage of blocked mechanisms for power distribution is one of the most popular and effective ways to improve the off-road vehicle performance. However, the lock of differential may adversely affect the stability and control of vehicle because of the unobvious redistribution of reactions acting on wheels, which consequently leads to poor performance and safety properties. Problems of rational distribution of power in transmissions of all-wheel drive vehicles, as well as research in the field of improving directional stability and active safety systems are among the priorities in modern automotive industry.
2017-03-28
Technical Paper
2017-01-0866
Edwin N. Quiros, Karl B.N. Vergel, Ernesto B. Abaya
Abstract This paper presents a preliminary study to estimate, using on-road and laboratory tests, the mileage range of liquefied petroleum gas (LPG) as an alternative fuel for diesel-fed public utility jeepneys in the Philippines. Data from the study would be used by the Philippine Department of Energy to formulate and implement alternative fuel programs for public transport. On-road fuel consumption, load factor, and GPS speed data from selected in-use LPG and diesel jeepneys plying a chosen urban route were gathered to develop corresponding drive cycles for chassis dynamometer testing at 100% load factor were conducted to estimate an upper limit for fuel consumption. Measured on-road diesel jeepney mileage was about 6.7 km/liter at 63.5% load factor while that for LPG jeepney was 3.8-4.2 km/liter at 59.8% load factor. Drive cycle tests yielded 5.2 km/liter for diesel and 2.6-3.1 km/liter for LPG.
2017-03-28
Technical Paper
2017-01-0869
Job Immanuel Encarnacion, Edwin Quiros
Abstract The Philippine Biofuels Act of 2006 (RA 9367) requires commercial diesel fuel to be mixed with Coconut Methyl Ester (CME) in accordance with the Philippine Clean Air Act of 1999 (RA 8749). As of 2015, the blend percentage is at 2% CME v/v, contrary to the scheduled 5% as stipulated in the biofuels act. Researches done locally showing the performance and emissions of CME-fueled engines are few and thus the basis for the CME percentage increase is still questionable and hampers the drive for the further implementation of the policy. The study investigates the influence of varying percentages of CME blends (2%, 5%, 10%, 15%, 20% v/v) to the performance and emissions of a heavy-duty turbocharged common rail direct injection (CRDI) engine. The engine is run at steady state at partial load (50Nm and 250 Nm) and at near full load (500Nm). Each run is set at three pedal positions, α (25%, 50% and 60%), controlled directly from the engine control unit.
2017-03-28
Technical Paper
2017-01-1208
Kristin R. Cooney
Abstract This paper will discuss a compliance demonstration methodology for UN38.3, an international regulation which includes a series of tests that, when successfully met, ensure that lithium metal and lithium ion batteries can be safely transported. Many battery safety regulations, such as FMVSS and ECE, include post-crash criteria that are clearly defined. UN38.3 is unique in that the severity of the tests drove changes to battery design and function. Another unique aspect of UN38.3 is that the regulatory language can lead to different interpretations on how to run the tests and apply pass/fail criteria; there is enough ambiguity that the tests could be run very differently yet all meet the actual wording of the regulation. A process was created detailing exactly how to run the tests to improve consistency among test engineers. As part of this exercise, several tools were created which assist in generating a test plan that complies with the UN38.3 regulation.
2017-03-28
Technical Paper
2017-01-1000
Jong Lee, Yu Zhang, Tom Tzanetakis, Michael Traver, Melanie Moses-DeBusk, John Storey, William Partridge, Michael Lance
Abstract Greenhouse gas regulations and global economic growth are expected to drive a future demand shift towards diesel fuel in the transportation sector. This may create a market opportunity for cost-effective fuels in the light distillate range if they can be burned as efficiently and cleanly as diesel fuel. In this study, the emission performance of a low cetane number, low research octane number naphtha (CN 34, RON 56) was examined on a production 6-cylinder heavy-duty on-highway truck engine and aftertreatment system. Using only production hardware, both the engine-out and tailpipe emissions were examined during the heavy-duty emission testing cycles using naphtha and ultra-low-sulfur diesel (ULSD) fuels. Without any modifications to the hardware and software, the tailpipe emissions were comparable when using either naphtha or ULSD on the heavy duty test cycles.
2017-03-28
Technical Paper
2017-01-0894
Nishant Singh
Abstract Improving fuel economy has been a key focus across the automotive industry for several years if not decades. For heavy duty commercial vehicles, the benefits from minor gains in fuel economy can lead to significant savings for fleets as well as owners and operators. Additionally, the regulations require vehicles to meet certain GHG standards which closely translate to vehicle fuel economy. For current state of the art fuel economy technologies, incremental gains are so miniscule that measurements on the vehicle are inadequate to quantify the benefits. Engineers are challenged with high level of variability to make informed decisions. In such cases, highly controlled tests on Engine and Powertrain dynamometers are used, however, there is an associated variability even with these tests due to factors such as part to part differences, deterioration, fuel blends and quality, dyno control capabilities and so on.
2017-03-28
Technical Paper
2017-01-1503
Jared Johan Engelbrecht, Tony Russell Martin, Piyush M. Gulve, Nagarjun Chandrashekar, Amol Dwivedi, Peter Thomas Tkacik, Zachary Merrill
Abstract Most commercial heavy-duty truck trailers are equipped with either a two sensor, one modulator (2S1M) or four sensors, two modulator (4S2M) anti-lock braking system (ABS). Previous research has been performed comparing the performance of different ABS modules, in areas such as longitudinal and lateral stability, and stopping distance. This study focuses on relating ABS module type and wheel speed sensor placement to trailer wheel lock-up and subsequent impact to tire wear for tandem axle trailers with the Hendrickson air-ride suspension. Prior to tire wear inspection, functionality of the ABS system was testing using an ABS scan tool communicating with the SAE J1587 plug access port on the trailer. Observations were documented on trailers using the 2S1M system with the wheel speed sensor placed on either the front or rear axle of a tandem pair.
2017-03-28
Journal Article
2017-01-1510
Kisun Song, Kyung Hak Choo, Dimitri Mavris
Abstract In early phases of conceptual design stages for developing a new car in the modern automobile industry, the lack of systematic methodology to efficiently converge to an agreement between the aesthetics and aerodynamic performance tremendously increases budget and time. During these procedures, one of the most important tasks is to create geometric information which is versatilely morphable upon the demands of both of stylists and engineers. In this perspective, this paper proposes a Spline-based Modeling Algorithm (SMA) to implement into performing aerodynamic design optimization research based on CFD analysis. Once a 3-perspective schematic of a car is given, SMA regresses the backbone boundary lines by using optimum polynomial interpolation methods with the best goodness of fit, eventually reconstructing the 3D shape by linearly interpolating from the extracted boundaries minimizing loss of important geometric features.
2017-03-28
Technical Paper
2017-01-1478
Srinivas Kurna, Sajal Jain, Palish Raja, Laxman Vishwakarma
Abstract In an automobile, main function of the steering system is to allow the driver to guide the vehicle on a desired course. Steering system consists of various components & linkages. Using these linkages, the torque from steering wheel is transferred to tyre which results in turning of the vehicle. Over the life of vehicle, these steering components are subjected to various loading conditions. As steering components are safety critical parts in the vehicle, therefore they should not fail while running because it will cause vehicle breakdown. In commercial vehicle segment, vehicle breakdown means delay in freight delivery which results in huge loss to costumer. Therefore, while designing steering components one should consider all the possible loadings condition those are possible. But, it can’t be done through theoretical calculation. Therefore, physical tests have to be carried out to validate design of steering system, which is very costly & time-consuming process.
2017-03-28
Technical Paper
2017-01-1490
Silvia Faria Iombriller
Abstract The air suspension development and its applications have becoming increasingly relevant for commercial vehicles to provide dynamic ride comfort to driver and reduce the load impact onto driver and or cargo. This paper shows the analysis and application of an air suspension system for commercial tractor vehicles and its dynamic influence. A special focus was given to pneumatic actuation system, responsible for leveling and control of suspension´s stiffness under different conditions of usage, laden and unladed. The project was conducted starting with the vehicle dynamic performance analysis, evaluating the pneumatic suspension circuit modifications in order to obtain vehicle dynamic behavior improvement, ensuring directional stability under different maneuvering conditions.
2017-03-28
Technical Paper
2017-01-1495
Srinivas Kurna, Ruchik Tank, Krishna Srikanth Achanta
1. Abstract At the time of invention of road coaches, the vehicle consisted only of an axle with wheels and a body attached. Smooth roads were built for a better ride comfort however they were not consistent. The road coaches were too bumpy and uncomfortable for the passenger along with the driver who was not able to control the vehicle. That's why the engineers had to shift their attention to the suspension system for a better ride comfort and handling. The technology has advanced with time so as the suspension system. Rubber ended type leaf spring is one of the suspension system types available in the industry. The main function of a suspension in order of importance is as below: 1 Acts as a cushioning device ensuring the comfort of the driver and passengers;2 Maximizes the contact between the tires and the road surface to provide steering stability with good handling;3 Protects the vehicle itself and any cargo or luggage from damage and wear.
2017-03-28
Technical Paper
2017-01-1538
Jiaye Gan, Longxian Li, Gecheng Zha, Craig Czlapinski
Abstract This paper conducts numerical simulation and wind tunnel testing to demonstrate the passive flow control jet boat tail (JBT) drag reduction technique for a heavy duty truck rear view mirror. The JBT passive flow control technique is to introduce a flow jet by opening an inlet in the front of a bluff body, accelerate the jet via a converging duct and eject the jet at an angle toward the center of the base surface. The high speed jet flow entrains the free stream flow to energize the base flow, increase the base pressure, reduces the wake size, and thus reduce the drag. A baseline heavy duty truck rear view mirror is used as reference. The mirror is then redesigned to include the JBT feature without violating any of the variable mirror position geometric constraints and internal control system volume requirement. The wind tunnel testing was conducted at various flow speed and yaw angles.
2017-03-28
Technical Paper
2017-01-1531
Keiichi Taniguchi, Akiyoshi Shibata, Mikako Murakami, Munehiko Oshima
Abstract This paper describes a study of drag reduction devices for production pick-up trucks with a body-on-frame structure using full-scale wind tunnel testing and Computational Fluid Dynamics (CFD) simulations. First, the flow structure around a pick-up truck was investigated and studied, focusing in particular on the flow structure between the cabin and tailgate. It was found that the flow structure around the tailgate was closely related to aerodynamic drag. A low drag flow structure was found by flow analysis, and the separation angle at the roof end was identified as being important to achieve the flow structure. While proceeding with the development of a new production model, a technical issue of the flow structure involving sensitivity to the vehicle velocity was identified in connection with optimization of the roof end shape. (1)A tailgate spoiler was examined for solving this issue.
2017-03-28
Technical Paper
2017-01-1345
Ramachandra bhat, Nitin Sharma, Clifford Rivard, Kevin Thomson
Abstract During development of new vehicles, CAE driven optimizations are helpful in achieving the optimal designs. In the early phase of vehicle development there is an opportunity to explore shape changes, gage reduction or alternative materials as enablers to reduce weight. However, in later phases of vehicle development the window of opportunity closes on most of the enablers discussed above. The paper discusses a simplified methodology for reducing the weight in design cycle for truck frames using parametric Design of Experiments (DOE). In body-on-frame vehicles, reducing the weight of the frame in the design cycle without down gaging involves introducing lightening holes or cutouts while still maintaining the fatigue life. It is also known that the lightening holes might cause stress risers and be detrimental to the fatigue life of the component. Thus the ability to identify cutout locations while maintaining the durability performance becomes very critical.
2017-03-28
Technical Paper
2017-01-1333
Sasikumar P, C. Sujatha, Chinnaraj K.
Abstract In commercial vehicles, exhaust system is normally mounted on frame side members (FSM) using hanger brackets. These exhaust system hanger brackets are tested either as part of full vehicle durability testing or as a subsystem in a rig testing. During initial phases of product development cycle, the hanger brackets are validated for their durability in rig level testing using time domain signals acquired from mule vehicle. These signals are then used in uni-axial, bi-axial or tri-axial rig facilities based on their severity and the availability of test rigs. This paper depicts the simulation method employed to replicate the bi-directional rig testing through modal transient analysis. Finite Element Method (FEM) is applied for numerical analysis of exhaust system assembly using MSC/Nastran software with the inclusion of rubber isolator modeling, meshing guidelines etc. Finite Element Analysis (FEA) results are in good agreement with rig level test results.
2017-03-28
Technical Paper
2017-01-1341
Alok Kumar, Sandeep Sharma
Abstract Public conveyance such as a bus is a major contributor to socio - economic development of any geography. The international market for passenger bus needed to be made viable in terms of passenger comfort, minimum operational costs of the fleet by reduced fuel consumption through light weighting and yet robust enough to meet stringent safety requirements. Optimized design of bus body superstructure plays vital role in overall performance and safety, which necessitates to evaluate bus structure accurately during initial phase of design. This paper presents a robust methodology in numerical simulation for enhancing the structural characteristics of a bus body with simultaneous reduction in the weight by multi-material optimization while supplemented with sensitivity and robustness analysis. This approach ensures significant reduction in vehicle curb weight with promising design stiffness.
2017-03-28
Technical Paper
2017-01-1089
Jose Grande, Julio Abraham Carrera, Manuel Dieguez Sr
Abstract Exhaust Gas Recirculation (EGR) has been in use for many years to control NOx emissions in commercial vehicle applications. Emissions limits are tighter with every new regulation while durability requirements continue to increase, so EGR system manufacturers must be able to provide high performance and robust designs even with high thermal loads. The commercial vehicle market is characterized by lower production rates than passenger car programs and the same engine must cope with multiple applications that have totally different engine calibrations. In some cases it is necessary to design two or more EGR systems for an engine platform, with a consequential impact on cost and development timeline. The optimal design of an EGR system needs to take into consideration several topics related with performance and durability: efficiency and pressure drop, fouling, boiling, thermal fatigue, vibration, pressure fatigue and corrosion among others.
2017-03-28
Technical Paper
2017-01-1427
Daniel Koch, Gray Beauchamp, David Pentecost
Abstract Tire disablement events can cause a drag force that slows a vehicle. In this study, the magnitude of the deceleration was measured for different phases of 29 high speed tire tread separation and air loss tests. These deceleration rates can assist in reconstructing the speed of a vehicle involved in an accident following a tire disablement.
2017-03-28
Technical Paper
2017-01-1426
Wesley D. Grimes, Thomas H. Vadnais, Gregory A. Wilcoxson
Abstract The time/distance relationship for a heavy truck accelerating from a stop is often needed to accurately assess the events leading up to a collision. Several series of tests were conducted to document the low speed acceleration performance of a 2016 Freightliner Cascadia truck tractor equipped with a 12-speed automated manual transmission in Auto Mode. Unlike tests in previous papers, the driver never manually shifted gears. These tests included three trailer load configurations and two different acceleration rates. Data were gathered with both a VBOX and with the Detroit Diesel Diagnostic Link (DDDL) software.
2017-03-28
Technical Paper
2017-01-1423
Alan F. Asay, Christopher D. Armstrong, Bradley Higgins, John Steiner
Abstract The rear override crash behavior of full-size and light duty pickup trucks was examined. A series of ten full-scale, front and rear override impact crash tests were conducted involving four full-size pickup trucks, two light duty pickup trucks, and one sport utility vehicle (SUV). The tests were conducted utilizing a fabricated steel rigid barrier mounted on the front of the Massive Moving Barrier (MMB) test device with full overlap of the test vehicle. Crush ranged from 25.0 to 77.9 inches for impact speeds of 21.7 to 36.0 mph. These override tests on pickups were conducted to provide more basis in an area that is underrepresented in the literature. Each test was documented and measured prior to, and following, the crash test. The stiffness parameters were calculated and presented using constant stiffness, force saturation, and the power law damage models.
2017-03-28
Technical Paper
2017-01-1424
Mark Fabbroni, Jennifer Rovt, Mark Paquette
Abstract Collision reconstruction often involves calculations and computer simulations, which require an estimation of the weights of the involved vehicles. Although weight data is readily available for automobiles and light trucks, there is limited data for heavy vehicles, such as tractor-semitrailers, straight trucks, and the wide variety of trailers and combinations that may be encountered on North American roads. Although manufacturers always provide the gross vehicle weight ratings (GVWR) for these vehicles, tare weights are often more difficult to find, and in-service loading levels are often unknown. The resulting large uncertainty in the weight of a given truck can often affect reconstruction results. In Canada, the Ministry of Transportation of Ontario conducted a Commercial Vehicle Survey in 2012 that consisted of weight sampling over 45,000 heavy vehicles of various configurations.
2017-03-28
Technical Paper
2017-01-1419
Smruti Panigrahi, Jianbo Lu, Sanghyun Hong
Abstract Characterizing or reconstructing incidents ranging from light to heavy crashes is one of the enablers for mobility solutions for fleet management, car-sharing, ride-hailing, insurance etc. While crashes involving airbag deployment are noticeable, light crashes without airbag deployment can be hidden and most drivers do not report these incidents. In this paper, we are using vehicle responses together with a dynamics model to trace back if abnormal forces have been applied to a vehicle so as to detect light crashes. The crash location around the perimeter of the vehicle, the direction of the crash force, and the severity of the crashes are all determined in real-time based on on-board sensor measurements which has further application in accident reconstruction. All of this information will be integrated to a feature called “Incident Report”, which enable reporting of minor accidents to the relevant entities such as insurance agencies, fleet managements, etc.
2017-03-28
Journal Article
2017-01-1416
B. Nicholas Ault, Daniel E. Toomey
Abstract Reconstruction of passenger vehicle accidents involving side impacts with narrow objects has traditionally been approached using side stiffness coefficients derived from moveable deformable barrier tests or regression analysis using the maximum crush in available lateral pole impact testing while accounting for vehicle test weight. Current Lateral Impact New Car Assessment Program (LINCAP) testing includes 20 mph oblique lateral pole impacts. This test program often incorporates an instrumented pole so the force between the vehicle and pole at several elevations along the vehicle - pole interface is measured. Force-Displacement (F-D) characteristics of vehicle structures were determined using the measured impact force and calculated vehicle displacement from on-board vehicle instrumentation. The absorbed vehicle energy was calculated from the F-D curves and related to the closing speed between the vehicle and the pole by the vehicle weight.
Viewing 211 to 240 of 7720