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Technical Paper

Fuel Consumption and Performance Benefits of Electrified Powertrains for Transit Buses

2018-04-03
2018-01-0321
Abstract This study presents a process to quantify the fuel saving potential of electrified powertrains for medium and heavy duty vehicles. For this study, equivalent vehicles with electrified powertrains are designed with the underlying principle of not compromising on cargo carrying capacity or performance. Several performance characteristics, that are relevant for all types of medium and heavy duty vehicles, were identified for benchmarking based on the feedback from the industry. Start-stop hybrids, parallel pre-transmission hybrids, plug-in hybrids, and battery electric vehicles are the technology choices in this study. This paper uses one vehicle as an example, explains the component sizing process followed for each powertrain, and examines each powertrain’s fuel saving potential. The process put forth in this paper can be used for evaluating vehicles that belong to all medium and heavy duty classes.
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
Abstract 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 highly compact. 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 8.9 L engine was chosen as a proof of concept platform due to its availability 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

Solid Particle Number and Ash Emissions from Heavy-Duty Natural Gas and Diesel w/SCRF Engines

2018-04-03
2018-01-0362
Abstract Solid and metallic ash particle number (PN) and particulate matter (PM) mass emission measurements were performed on a heavy-duty (HD) on-highway diesel engine and a compressed natural gas (CNG) engine. Measurements were conducted under transient engine operation that included the FTP, WHTC and RMC. Both engines were calibrated to meet CARB ultra low NOX emission target of 0.02 g/hp-hr, a 90% reduction from current emissions limit. The HD diesel engine final exhaust configuration included a number of aftertreatement sub-systems in addition to a selective catalytic reduction filter (SCRF). The stoichiometric CNG engine final configuration included a closed coupled Three Way Catalyst (ccTWC) and an under floor TWC (ufTWC). The aftertreatment systems for both engines were aged for a full useful life (FUL) of 435,000 miles, prior to emissions testing. PM mass emissions from both engines were comparable and well below the US EPA emissions standard.
Technical Paper

Towards Electrification of Urban Buses Using Model Based Analysis

2018-04-03
2018-01-0408
Abstract City buses electrification gains increasing interest as a promising solution for both zero emissions in urban environment and energy consumption minimization. Nevertheless, global spread of battery electric buses may be currently questionable, mainly due to traveling range limitations. In this respect, the aim of this work is to elucidate performance aspects of battery electric powertrain systems for urban buses. Instead of exhaustive testing, cost-effective model based vehicle analysis is proposed for quantifying and understanding electric propulsion system performance and respective vehicle energy consumption. First, an indicative 12-m battery electric urban bus model was developed and its performance was simulated under both steady state conditions, as well as the legislated Braunschweig driving cycle.
Technical Paper

FEM Simulation Methodology for Accurately Capturing the Experimental Vibration Response of ECM Assembly on a Commercial Vehicle

2018-04-03
2018-01-0467
Abstract This paper presents an experimental setup and an equivalent FEM simulation methodology to accurately predict the response of Engine Control Module (ECM) assembly mounted on a commercial vehicle subjected to road vibrations. Comprehensive vibration study is carried out. It involved Modal characteristics determination followed by random vibration characterization of the ECM assembly. A hammer impact experiment is first performed in lab to estimate the natural frequencies and mode shapes of ECM assembly. Mounting conditions in test specimen are kept similar to the actual mounting settings on vehicle. Natural frequencies and mode shapes predicted from free vibration experiment are compared with finite element (FE) based modal analysis. The importance of capturing the assembly stiffness more accurately by incorporating pre-stress effects like bolt-pretension and gravity, is emphasized.
Technical Paper

Steering Shaft Separation with a Collision Involved Heavy Duty Steering Gear

2018-04-03
2018-01-0524
Abstract A crash of a medium duty truck led to a study of the failure mechanism of the truck’s steering system. The truck, after being involved in a multi-vehicle vehicle collision, was found with its steering input shaft disconnected from the steering gear. The question arose whether the steering gear failure was a result of the collision, or causative to the collision. An in-depth investigation was conducted into whether forces on the vehicle due to the collision could cause the steering shaft to separate from the steering gear. Additionally, the performance of the steering gear with the adjuster nut progressively backed off was studied to determine the feedback a driver would receive if the steering gear came progressively apart. From the results of these studies, conclusions with regard to the crash causation were reached.
Technical Paper

Introduction to Traffic Signal Data Loggers and their Application to Accident Reconstruction

2018-04-03
2018-01-0527
Abstract Each year in the United States, approximately 1 million collisions occur at signalized intersections, representing over 15% of all collisions and almost 9% of traffic fatalities. Engineers seeking to understand the roadway, vehicular, and driver factors related to these collisions are often asked to investigate and assess the traffic signal timing, right of way issues, and the signal indications displayed to involved drivers during the period of time leading up to and including the impact events. Until relatively recently, investigators were limited by the absence of any recording devices within the systems used for traffic signal phasing and timing. Accident reconstruction methods have long relied on the generalized signal phasing and timings programmed for that intersection by the responsible jurisdiction, combined with the vehicle dynamics calculated for the collision sequence in conjunction with witness testimony regarding signal indications and phase changes.
Technical Paper

Videogrammetry in Vehicle Crash Reconstruction with a Moving Video Camera

2018-04-03
2018-01-0532
Abstract In an accident reconstruction, vehicle speeds and positions are always of interest. When provided with scene photographs or fixed-location video surveillance footage of the crash itself, close-range photogrammetry methods can be useful in locating physical evidence and determining vehicle speeds and locations. Available 3D modeling software can be used to virtually match photographs or fixed-location video surveillance footage. Dash- or vehicle-mounted camera systems are increasingly 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 but EDR data is unavailable for either of the vehicles involved.
Technical Paper

Truck Brake Failure: Differences between Failure Modes for Drum and Disc Brakes

2018-04-03
2018-01-0528
Abstract On-highway heavy trucks are fitted with air disc brakes with increasing frequency. Disc brakes and traditional air drum brakes have different adjustment and heat dissipation characteristics. These differences lead to different failure modes when overheated. This paper describes how adjustment and other in-use factors affect the general braking capability of on-highway trucks fitted with disc and drum brakes. Simulations of a loaded tractor-trailer on a long, down-hill grade are used to predict brake temperature increase over time, and how that temperature increase can result in a runaway condition. The tractor and trailer are modeled with both traditional drum brakes and new disc brakes to illustrate operational differences between the two brake types.
Technical Paper

Design and Development of Active On-Board Alcohol Detection System with Safety Features for Commercial Vehicles

2018-04-03
2018-01-0602
Abstract Drink & drive has caused the increased rate of commercial vehicle accidents in the world due to the slow response to judgment and reasoning. According to research study 70% accidents are happened due to drunk & drive, it causes loss of human life and economic damage. Research has proven that drunk drivers exhibit aggressive driving behavior and apply more force during braking. While public health awareness and legal restrictions can assist in educating and discouraging people from drunk & drive, a more fool-proof method is not available in the market for commercial vehicles. Currently, a low cost, fail-safe onboard alcohol detection, and vehicle safety system is the need of the hour. This paper deals with the design & development of a low cost active onboard breath alcohol detection system and it’s on vehicle validation. Further, it explains the type of alcohol detection sensor used, controller design, logic programming and system packaging.
Technical Paper

A Novel Three-Planetary-Gear Power-Split Hybrid Powertrain for Tracked Vehicles

2018-04-03
2018-01-1003
Abstract Tracked vehicles are widely used for agriculture, construction and many other areas. Due to high emissions, hybrid electric driveline has been applied to tracked vehicles. The hybrid powertrain design for the tracked vehicle has been researched for years. Different from wheeled vehicles, the tracked vehicle not only requires high mobility while straight driving, but also pursues strong steering performance. The paper takes the hybrid track-type dozers (TTDs) as an example and proposes an optimal design of a novel power-split powertrain for TTDs. The commercial hybrid TTD usually adopts the series hybrid powertrain, and sometimes with an extra steering mechanism, which has led to low efficiency and made the structure more complicated. The proposed three-planetary-gear power-split hybrid powertrain can overcome the problems above by utilizing the characteristics of planetary gear sets.
Technical Paper

Optimization of Heavy Duty Diesel Engine Lubricant and Coolant Pumps for Parasitic Loss Reduction

2018-04-03
2018-01-0980
Abstract As fuel economy becomes increasingly important in all markets, complete engine system optimization is required to meet future standards. In many applications, it is difficult to realize the optimum coolant or lubricant pump without first evaluating different sets of engine hardware and iterating on the flow and pressure requirements. For this study, a Heavy Duty Diesel (HDD) engine was run in a dynamometer test cell with full variability of the production coolant and lubricant pumps. Two test stands were developed to allow the engine coolant and lubricant pumps to be fully mapped during engine operation. The pumps were removed from the engine and powered by electric motors with inline torque meters. Each fluid circuit was instrumented with volume flow meters and pressure measurements at multiple locations. After development of the pump stands, research efforts were focused on hardware changes to reduce coolant and lubricant flow requirements of the HDD engine.
Technical Paper

Robust Path Tracking Control for Autonomous Heavy Vehicles

2018-04-03
2018-01-1082
Abstract With high maneuverability and heavy-duty load capacity, articulated steer vehicles (ASV) are widely used in construction, forestry and mining sectors. However, the steering process of ASV is much different from wheeled steer vehicles and tractor-trailer vehicles. Unsuitable steering control in path following could easily give rise to the “snaking” behaviour, which greatly reduces the safety and stability of ASV. In order to achieve precise control for ASV, a novel path tracking control method is proposed by virtual terrain field (VTF) method. A virtual U-shaped terrain field is assumed to exist along the reference path. The virtual terrain altitude depends on the lateral error, heading error, preview distance and road curvature. If the vehicle deviates from the reference line, it will be pulled back to the lowest position under the influence of additional lateral tire forces which are caused by the virtual banked road.
Technical Paper

Exploring Telematics Big Data for Truck Platooning Opportunities

2018-04-03
2018-01-1083
Abstract NREL completed a temporal and geospatial analysis of telematics data to estimate the fraction of platoonable miles traveled by class 8 tractor trailers currently in operation. This paper discusses the value and limitations of very large but low time-resolution data sets, and the fuel consumption reduction opportunities from large scale adoption of platooning technology for class 8 highway vehicles in the US based on telematics data. The telematics data set consist of about 57,000 unique vehicles traveling over 210 million miles combined during a two-week period. 75% of the total fuel consumption result from vehicles operating in top gear, suggesting heavy highway utilization. The data is at a one-hour resolution, resulting in a significant fraction of data be uncategorizable, yet significant value can still be extracted from the remaining data. Multiple analysis methods to estimate platoonable miles are discussed.
Technical Paper

Working Load Measurement and Analysis of Bolted Joint under Off-road Vehicle Operation

2018-04-03
2018-01-1234
Abstract In this study, we propose a method of measuring and analyzing the load on bolted joints used in a machine under off-road vehicle operation. Working load measurement under actual machine operation and the results of its analysis are shown as load frequency diagrams. An example of the measurement analysis of a load (three types of load: axial force, bending moment, and torsional torque) added to a bolted joint shank during actual machine operation is shown. In this paper, we describe how to apply the results of load analysis to the load condition at the design and experimental development stages.
Technical Paper

CFD Study of Low Soot Spray Combustionin a Heavy-Duty Diesel Engine

2018-04-03
2018-01-0186
Abstract This CFD study focuses on the influence of the nozzle diameter on the mixing process and the soot formation and oxidation process in a heavy-duty diesel engine. The CFD simulation is based on the Reynolds Averaged Navier-Stokes approach. The engine set-up is similar to an experimental case that showed rather low soot emission. The aim of the paper is to improve the understanding of the physics of the mixing process in a real engine environment with the attention to scrutinize its effect of fuel injection on combustion and soot emission. Two non-reacting cases with different injector nozzle diameters but constant injection pressure and their corresponding reacting cases are simulated with dynamic mesh motion and fuel spray modeling. The influence of injections on the mixing, combustion and emissions is analyzed and the simulation results are compared with the measurement data.
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
Abstract 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

Preliminary Study of LIDAR Scanner-Based Collision Avoidance and Automated Guided Systems for Autonomous Power Equipment Products

2018-04-03
2018-01-0032
Abstract Technology is continuously being developed to prevent self-driving vehicles from crashing. That technology could also be considered for other autonomous products. Collision avoidance in automated, guided systems using a light detection and ranging (LIDAR) scanner has been studied for application in low-speed autonomous Honda Power Equipment products, such as self-driving lawn mowers. The automotive application of a LIDAR scanner for autonomous driving is used for obstacle detection and offline local area. Such delineations do not exist in areas where power equipment is used, such as grass fields; therefore, identifying object height and distance, is a relatively new area. For this study, a small LIDAR scanner with a resolution of 0.01 m and a measurement range of 0.05 m to 40.00 m was used on a Honda self-driving lawn mower. The measurement distance data was directly processed in the scanner, enabling the drive unit to obtain distance information during actual operation.
Technical Paper

GPS Guided Autonomous Navigation of a Small Agricultural Robot with Automated Fertilizing System

2018-04-03
2018-01-0031
Abstract In this paper, the design, implementation, and testing of an autonomous agricultural robot with GPS guidance is presented. This robot is also responsible for weed detection and killing by spraying appropriate herbicide as well as fertilizing. This rover is powered by 5 12 V electric bike batteries and two electric motors. Machine learning algorithms such as Haar feature-based cascade classifiers has been utilized to detect three kinds of common weeds found in a corn field. The robot control system consists of GPS guided control of propulsion system and steering actuators, an image processing and detection system, and a spray control system for herbicide and fertilizer applications. Multiple microprocessors such as Raspberry Pi 3, Arduino, as well as an on-board computer have used to provide all control functions in an integrated fashion. Open sources software such as Mission Planner and ReachView have been used to provide autonomous guidance of the vehicle.
Technical Paper

Implementation of Electrified Air Conditioning on a Class 8 Long Haul Vehicle

2018-04-03
2018-01-0061
Abstract Current methods employing electrified air conditioning (A/C) in class 8 long haul vehicles are hampered by insufficient capacity to cool the entire cabin both in sleeper mode and during normal on the road operation. A highly efficient single system solution is needed that meets cooling requirements under all operational modes without exceeding the power requirements that an onboard battery system can support. Results presented in this paper demonstrate the ability of an electrified A/C system to exceed cabin pulldown requirements within onboard electrical power availability while also meeting the low power draw requirements of sleeper mode operation. Results also demonstrate power electronics technology has advanced to the point that delivering ~5 kW of power at 48VDC (i.e. ~100A) can be accomplished in a reasonable sized package for commercial vehicle applications.
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