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Journal Article

Analysis of Single-Vehicle Accidents in Japan Involving Elderly Drivers

2018-05-11
2018-01-9752
The Japanese population is aging rapidly, raising the number of traffic accidents involving elderly drivers. In Japan, single-vehicle accidents are a serious problem because they often result in fatalities. We analyzed these accidents by vehicle type, age group, and driving area, and found that many of them occurred when young or elderly people were driving light motor vehicles (K-type vehicles) in non-urban areas. We analyzed the characteristics of single-vehicle accidents. On the assumption that the number of rear-end collisions is a proxy for the traffic volume, we used the number of such collisions to control for driving frequency. It was found that in single-vehicle accidents, elderly drivers were at higher risk than other age groups, especially when driving K-type vehicles in non-urban areas. A possible explanation is the higher frequency with which the elderly drive K-type vehicles in areas where there are few other vehicles on the road.
Journal Article

Abdominal Injury Patterns in Frontal Crashes: Analysis of Front and Rear Seat Occupants using NASS/CDS and CIREN

2018-05-11
2018-01-9751
Field accident data from the National Automotive Sampling System/Crashworthiness Data System (NASS/CDS) and the Crash Injury Research and Engineering Network (CIREN) databases were used to identify the factors affecting abdominal injury type and incidence for front and rear seat occupants in frontal collisions. The NASS/CDS analysis was conducted to identify the nature and magnitude of abdominal injuries, while a separate CIREN analysis was conducted to investigate the mechanistic differences between types of abdominal organ injuries. Abdominal injury risk was found to increase with increasing occupant age in both the front and rear seating positions. Abdominal injury risk also increased with factors associated with more severe collisions including the number of crash events, extent of frontal crush, collision type, and crash speed.
Journal Article

Deicing Simulations for Windshields in Commercial Vehicle Applications

2018-04-13
2018-01-9176
Windshield deicing performance is a key metric for HVAC system development and optimization within the sphere of commercial vehicle design. The primary physical properties that drive this metric are pressure drops in the HVAC ducting, flow rate of the air through the system, and the transient warm up curve of the HVAC unit. However, many design engineers also have to take underhood packaging into consideration while trying to optimize a new HVAC system design. This study leverages historical deicing simulation methodologies in conjunction with modern computational horsepower so as to optimize the HVAC ductwork in the studied commercial truck at the front end of the design process. By iterating on a design in the computational domain under steady-state and transient flow and thermal conditions, a robust HVAC system design can be created even prior to the prototyping stage of development.
Journal Article

Investigation on Underhood Thermal Analysis of Truck Platooning

2018-04-13
2018-01-9175
A 3D CFD underhood thermal simulations are performed in two different vehicle platooning configurations; (i) single-lane and (ii) two-lane traffic conditions. The vehicle platooning consists of two identical vehicles, i.e. leading and trailing vehicle. In this work, heat exchangers are modeled by two different heat rejection rate models. In the first model, a constant heat rejection rates are considered as similar to no-traffic vehicle condition. In the other model, a varied heat rejection rates are implemented by considering an aerodynamic influence on fuel consumption rates. In a constant heat rejection rate model, the trailing vehicle thermal performance is significantly dropped in single-lane traffic due to reduced oncoming cold mass air flow velocities from leading vehicle. Also, the similar observations are found in two-lane traffic but at higher vehicle separation distances.
Technical Paper

Advanced Combustion for Improved Thermal Efficiency in an Advanced On-Road Heavy Duty Diesel Engine

2018-04-03
2018-01-0237
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.
Technical Paper

Deriving the validation protocol for isolator switches used in Commercial vehicles

2018-04-03
2018-01-0128
Automotive business is more focused towards delivering a highly durable and reliable product at an optimum cost. Anything falling short of customer expectation, will damage the reputation of the manufacturer. To exterminate this, all automotive components undergo stringent testing protocol during the design validation phase. Nevertheless, there are certain factors in the field which are seldom captured during design validation. This project aims at optimizing a validation methodology for Isolator switch based on field usage and conditions. Isolator switch is the main control switch which connects/disconnects the electrical loads from its source; battery. This switch is used in the electrical circuit of the vehicle to prevent the unwanted draining of battery when it is not needed (or) vehicle is in switched off state. In the electrical version of this switch uses electromagnetic coils to short the contacts.
Technical Paper

Analysis of the Effects of Diesel Injection Parameters in a Heavy Duty Iso-Butanol/Diesel Reactivity Controlled Compression Ignition (RCCI) Engine

2018-04-03
2018-01-0197
An advanced 3D-CFD computational study was done in order to study the simultaneous effects of diesel injection pressure and single injection timing on the amounts of pollutant emissions and engine performance in a heavy duty, single cylinder iso-butanol/Diesel reactivity controlled compression ignition (RCCI) engine. A reduced chemical n-heptane-n-butanol-PAH mechanism which consists of 76 species and 349 reactions was used to simulate the combustion process of the dual-fuel diesel engine. The baseline operation case was validated with Wang et al. research work and good agreements between in-cylinder mean pressure, the rate of heat release and amounts of pollutant emissions such as NOx, Particulate Matter (PM), unburnt hydrocarbons (UHC) and carbon monoxide (CO) was obtained. Twenty-one different strategies based on two variables (diesel direct injection timing and diesel injection pressure) have been investigated.
Technical Paper

A Numerical Study on the Sensitivity of Soot and NOx Formation to the Operating Conditions in Heavy Duty Engines

2018-04-03
2018-01-0177
In this paper, computation fluid dynamics (CFD) simulations are employed to describe the effect of flow parameters on the formation of soot and NOx in a heavy duty engine under low load and high load. The complexity of diesel combustion, specially when soot, NOx and other emissions are of interest, requires using a detailed chemical mechanism to have a correct estimation of temperature and species distribution. In this work, Multiple Representative Interactive Flamelets (MRIF) method is employed to describe the chemical reactions, ignition, flame propagation and emissions in the engine. A phenomenological model for soot formation, including soot nucleation, coagulation and oxidation with O2 and OH, is incorporated into the flamelet combustion model. Different strategies for modelling NOx are chosen to take into account the longer time scale for NOx formation. The numerical results are compared with experimental data to show the validity of the model for the cases under study.
Technical Paper

Fuel consumption and performance benefits of electrified powertrains for medium and heavy duty vehicles

2018-04-03
2018-01-0321
Electrified powertrains are gaining acceptance on the light duty vehicles, but their impact of medium and heavy duty vehicles are not well understood. There are several prototyping efforts funded by US DOE in demonstrating the benefits in certain vehicle segments, but a larger study including several types of trucks is needed to understand the impact of specific powertrain technologies. This study proposes the use of a fleet of 13 different vehicles from various class, vocation combinations. This will cover over 50% of the type of medium and heavy duty vehicles on US roads. The vehicles that enjoy the market share in each category is taken as the baseline. Their fuel consumption and performance is simulated in Autonomie. Equivalent vehicles with electrified powertrains are designed with the underlying principle of not compromising on cargo or performance. Several performance characteristics were identified for benchmarking based on the feedback from the industry.
Technical Paper

Integrated Exhaust Rocker Arm Lost Motion Compression Release Engine Brake with Novel Reset Mechanism for Heavy Duty Diesel Engines

2018-04-03
2018-01-0381
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.
Technical Paper

Experimental Investigation of Aerodynamic benefits of Class 8 Tractor-Trailer Platooning

2018-04-03
2018-01-0732
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.
Technical Paper

EVALUATION OF THE TECHNICAL LEVEL OF MODERN AGRICULTURAL TRACTORS SUBMITTED BY ON THE RUSSIAN MARKET

2018-04-03
2018-01-0657
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.
Technical Paper

Videogrammetry in Vehicle Crash Reconstruction with a Moving Video Camera

2018-04-03
2018-01-0532
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.
Technical Paper

An Optical Characterization of Dual-Fuel Combustion in Heavy-Duty Diesel Engine

2018-04-03
2018-01-0252
A developing practical approach of dual fuel combustion facilitates the fuel flexibility and provide a base to utilize diverse fuels in internal combustion engines. The abundance of natural gas and its clean burning property due to its lower C/H ratio has drawn the interest toward it. In addition, natural gas has high octane number and high auto-ignition temperature, which makes it a potential fuel to employ as a primary fuel in typical diesel engines with high compression ratio resulting in diesel like efficiency. In this study, DF-combustion involving methane (99.8% pure) as a primary fuel and diesel as a pilot fuel is subjected. In diesel-methane DF combustion, the combustion of lower reactivity fuel methane initiates through the energy provided by compression ignited pilot amount of high reactivity diesel fuel. The experimental investigation of DF-combustion was carried out by a natural luminosity optical method.
Technical Paper

Development and Optimization of Variable flow AC Compressor for commercial vehicles to reduce parasitic losses and improving efficiency of HVAC system.

2018-04-03
2018-01-0056
In modern era of commercial vehicle industry, comfort is one of the major parameter which improves vehicle running time that will lead to fleet owner's profitability. Air conditioning system is one such system whose primary function is to provide the preferred cooling and stabilize cabin temperature in hot climate conditions. Air-conditioned truck cabin not only gives better driver efficiency, along with comfortable environment for driver improving safety as well. AC compressor consumes power from engine directly affecting fuel economy and vehicle performance. With ever increasing demand for energy efficient systems and thermal comfort in automobiles, AC system needs to be optimized to deliver the required cooling performance with minimum AC power consumption. Hence reducing AC power consumption in vehicle is one of the key challenges for climate control engineers.
Technical Paper

Conceptual Design Challenges and Solutions in Power Shuttle Transmission development for Legacy tractors

2018-04-03
2018-01-0394
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.
Technical Paper

Correlation and verification of a tractor cab model using statistical energy analysis.

2018-04-03
2018-01-0142
A model of a tractor cab was built using Statistical Energy Analysis (SEA) best practices. In this paper, it is shown how this model was correlated using data measured using a volume velocity source in the laboratory. After correlation, the model was excited using acoustic loads measured during tractor operation. It was found that the data predicted by the model is in good agreement with the data measured inside the cabin during this test.It was concluded that SEA can be used as an engineering tool to predict the behavior under many different conditions and can be used to guide the development process.
Technical Paper

Truck and Sport Utility Vehicle Front End Stiffness Corridors

2018-04-03
2018-01-0518
A substantial number of side impact fatalities involve a truck or sport-utility vehicle (SUV) as the striking vehicle. While the body style of the SUV fleet has transitioned from primarily body-on-frame to unibody (UB) construction, few studies have examined if this results in different vehicle stiffness. Therefore, the purpose of the present study was to characterize front stiffness response of contemporary SUVs and trucks. Vehicle front impact test data were obtained from data published by the National Highway Traffic Safety Administration [NHTSA]. For all tests, force data were obtained from barrier load cells and stroke data were derived from accelerometers. Data from 53 truck and SUV tests were aggregated by class to obtain mean ± SD stiffness corridors: (1) compact UB SUV, (2) small UB SUV, (3) mid-size UB SUV, (4) frame SUV, and (5) frame truck. Across unibody SUV classes, stiffness varied from 1.3 – 1.5 kN/mm.
Technical Paper

Solid Particle Number and Ash Emissions from a Heavy Duty Natural Gas and Diesel w/DPF Engines

2018-04-03
2018-01-0362
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.
Technical Paper

Passenger Vehicle-Motorcycle Pre-Crash Trajectory Reconstruction and Conflict Analysis Results Based On an Extended Application of the Honda-DRI ACAT Safety Impact Methodology

2018-04-03
2018-01-0510
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.
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