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Technical Paper

Heavy Duty Off-Road Truck Exhaust System Design

2009-10-06
2009-01-2853
An important segment of power system design often left to the Original Equipment Manufacturer (OEM) is the engine exhaust system. The requirement of exhaust after treatment has increased the importance of exhaust systems to be impermeable and still retain their physical flexibility. To achieve the necessary flexibility, OEMs will often choose to incorporate an available expansion joint(s) into the exhaust system. Often, conversations with expansion joint suppliers result in the OEM having to supply vital information about the application or a vehicle to record acceleration and vibration information. Unfortunately, the cost of building low volume vehicles does not always afford the OEM with enough resources to develop a custom expansion joint for the exhaust system. As a result, it is important to understand what the proper inputs are, make a sound engineering judgment as to what the worst case magnitude may be and provide that information to different suppliers.
Technical Paper

The Lubricant Contribution to Improved Fuel Economy in Heavy Duty Diesel Engines

2009-10-06
2009-01-2856
Fuel economy of internal combustion engines played an important role for engine designers for decades. For heavy duty diesel engines, over the last 10 to 15 years however, fuel economy has in some cases been sacrificed for exhaust gas emission optimizations. Now that the industry seems to have reached the point of diminishing returns in the area of reducing diesel exhaust gas emissions, the focus is back on fuel economy. This paper addresses the impact that diesel engine lubricants can have on improving fuel economy. The evaluations discussed in this paper are based on fuel economy measurements in a standardized laboratory engine test.
Technical Paper

A STUDY OF DIFFERENT EGR ROUTES ON A HEAVY DUTY STOICHIOMETRIC NATURAL GAS ENGINE

2009-09-13
2009-24-0096
Exhaust gas recirculation (EGR) is a suitable strategy to optimize heavy duty natural gas (NG) engines. EGR could be utilized to have high specific power, with low thermal stress, but also to increase engine efficiency. NG fuelling permits a large flexibility in EGR system design, due to very clean engine exhaust. In this paper, three types of EGR routes have been studied. The best set up, which can introduce the highest EGR quantities, to provide the best reduction of the thermal load at rated power, was found to be a cooled low pressure EGR route. However high low pressure route (HLPR) could give the possibility to increase engine efficiency by modulating the power output in the widest un-throttled range operation.
Journal Article

Reconstruction of Wheel Forces Using an Intelligent Bearing

2016-04-05
2016-01-0092
Abstract Active vehicle safety and driving assistance systems can be made more efficient, more robust and less complex if wheel load information would be available. Although this information could be determined via numerous different methods, due to various reasons, no commercially feasible approach has yet been introduced. In this paper the approach of bearing load estimation is topic of interest. Using the bearing for load measurement has considerable advantages making it commercially attractive as: i) it can be performed on a non-rotating part, ii) all wheel loads can be measured and iii) usually the bearing serves the entire lifetime of the vehicle. This paper proposes a novel approach for the determination of wheel loading. This new approach, based on the strain variance on the surface of the bearing outer ring, is tested on a dedicated bearing test setup.
Journal Article

Long-Haul Truck Sleeper Heating Load Reduction Package for Rest Period Idling

2016-04-05
2016-01-0258
Abstract Annual fuel use for sleeper cab truck rest period idling is estimated at 667 million gallons in the United States, or 6.8% of long-haul truck fuel use. Truck idling during a rest period represents zero freight efficiency and is largely done to supply accessory power for climate conditioning of the cab. The National Renewable Energy Laboratory’s CoolCab project aims to reduce heating, ventilating, and air conditioning (HVAC) loads and resulting fuel use from rest period idling by working closely with industry to design efficient long-haul truck thermal management systems while maintaining occupant comfort. Enhancing the thermal performance of cab/sleepers will enable smaller, lighter, and more cost-effective idle reduction solutions. In addition, if the fuel savings provide a one- to three-year payback period, fleet owners will be economically motivated to incorporate them.
Technical Paper

Study of Energy Recovery System Based on Organic Rankine Cycle for Hydraulic Retarder

2016-04-05
2016-01-0239
Abstract The hydraulic retarder is an auxiliary braking device used in heavy duty vehicle. It generates braking forceby liquid damping effect and makes inertial energy into thermal energy of the transmission medium when the vehicleis in thedownhill. The traditional thermal management system of the hydraulic retarder dissipates the heat of transmission medium out of the vehicle directly, which causes a big waste of energy, meanwhilethe thermal management system components need to consume engine power. This study applies organic Rankine cycle (ORC)cooling system to meet the high power cooling requirements of the hydraulic retarder and recover waste heat energy from the transmission medium at the same time and then supply energy to the thermal management system, which could save the parasitic power of the engine and improve the comprehensive energy utilization ratio of the vehicle.
Technical Paper

Waste Heat Recovery by an Organic Rankine Cycle for Heavy Duty Vehicles

2016-04-05
2016-01-0234
Abstract The use of reciprocating internal combustion engines (ICE) dominates the sector of the in-the-road transportation sector, both for light and heavy duties. CO2 reduction is the technological driver, considering the severe worldwide greenhouse commitments. In ICE more than one third of the fuel energy used is rejected to the environment as thermal waste through the exhaust gases. Therefore, a greater fuel economy could be achieved, recovering this energy and converting it into useful electric power on board. Financial benefits will be produced in terms of fuel cost which will rebound similar benefits in terms of CO2 emitted. For long hauling vehicles, which run for thousands of miles, frequently at fixed engine operating conditions, this recovery appears very worthy of attention. In this activity, an ORC-based power unit was designed, built and tested fed by a heavy duty diesel engine, so contributing to the huge efforts on going in that specific sector.
Technical Paper

Design and Development of Demisting Device of a Commercial Vehicle and its Numerical as Well as Experimental Validation

2016-04-05
2016-01-0217
Abstract Adequate visibility through the vehicle windshield over the entire driving period is of paramount practical significance. Thin water film (fog) that forms on the windshield mainly during the winter season would reduce and disturb the driver’s visibility. This water film originates from condensing water vapor on inside surface of the windshield due to low outside temperatures. Primary source of this vapor is the passenger’s breath, which condenses on the windshield. Hot and dry air which impinges at certain velocity and angle relative to the windshield helps to remove the thin water film (defogging) and hence improves driver’s visibility. Hence a well-designed demisting device will help to eliminate this fog layer within very short span of time and brings an accepted level of visibility. An attempt is made here to design and develop a demisting device for a commercial vehicle with the help of numerical and analytical approach and later on validated with experimental results.
Journal Article

Design and Optimisation of the Propulsion Control Strategy for a Pneumatic Hybrid City Bus

2016-04-05
2016-01-1175
Abstract A control strategy has been designed for a city bus equipped with a pneumatic hybrid propulsion system. The control system design is based on the precise management of energy flows during both energy storage and regeneration. Energy recovered from the braking process is stored in the form of compressed air that is redeployed for engine start and to supplement the engine air supply during vehicle acceleration. Operation modes are changed dynamically and the energy distribution is controlled to realize three principal functions: Stop-Start, Boost and Regenerative Braking. A forward facing simulation model facilitates an analysis of the vehicle dynamic performance, engine transient response, fuel economy and energy usage.
Technical Paper

Optimal Control of a Diesel-Electric Powertrain During an Up-Shift

2016-04-05
2016-01-1237
Abstract To investigate the optimal controls of a diesel-electric powertrain during a torque controlled gearshift, a powertrain model is developed. A validated diesel-electric model is used as the power source and the transmission dynamics are described by different sets of differential equations during torque phase, synchronization phase and inertia phase of the gearshift. Using the developed model, multi-phase optimal control problems are formulated and solved. The trade-off between gearshift duration and driveline oscillations are calculated and efficient gearshift transients for a diesel-electric and pure diesel powertrain are then compared and analyzed.
Technical Paper

Critical Factors in the Development of Well-To-Wheel Analyses of Alternative Fuel and Advanced Powertrain Heavy-Duty Vehicles

2016-04-05
2016-01-1284
Abstract A heavy-duty vehicle (HDV) module of the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREETTM) model has been developed at Argonne National Laboratory. The fuel-cycle GREET model has been published extensively and contains data on fuel-cycles and vehicle operation of light-duty vehicles. The addition of the HDV module to the GREET model allows for well-to-wheel (WTW) analyses of heavy-duty advanced technology and alternative fuel vehicles (AFVs), which has been lacking in the literature. WTW analyses of HDVs becomes increasingly important to understand the fuel consumption and greenhouse gas (GHG) emissions impacts of newly enacted and future HDV regulations from the Environmental Protection Agency and the Department of Transportation’s National Highway Traffic Safety Administration.
Technical Paper

Multi-Objective Structural Optimization of a Chassis Frame

2016-04-05
2016-01-1398
Abstract Optimization of a structure which is subjected to simultaneous multiple load cases starts with the investigation of worst possible load case combination. This is called conventional optimization approach, which can be considered impractical due to the excessive CPU times in the application of multiple load cases. This computational difficulty can be overcome by deploying singular value decomposition (SVD) to find the worst possible load case against which the structure should be optimized. To this end, the SVD based optimization approach to optimization of a structure subject to simultaneous multiple load cases is presented. Conventional Multiobjective optimization and SVD based Multi-objective optimization approaches are applied to a sample Commercial Truck Chassis Frame structure for durability vs. weight objectives. This will enable designer to select the optimum design parameters out of the calculated Pareto sets.
Journal Article

Fire Protection in Military Ground Vehicles

2016-04-05
2016-01-1404
Abstract Fire protection, active and passive, has been, and is, an important area of concern during the design, development and deployment phases for all modern ground vehicles. All US military vehicles carry handheld fire extinguishers, and many tactical and all combat vehicles have automatic fire protection systems that protect the crew, engine, and in some cases, external components such as fuel tanks and wheels, from potentially catastrophic combat events involving fire. Vehicle designs also mitigate fire hazards by separating the vehicle occupants from the most flammable materials, e.g., fuel and ammunition, as much as practical. Explosion protection of the crew and passengers in military vehicles is a unique application with unique requirements that must balance suppression actions with safety limits.
Technical Paper

Full-Scale Burn Test of a 2007 Cargo Van

2016-04-05
2016-01-1403
Abstract Data from a full-scale vehicle burn test involving a cargo van illustrated how temperature distributions changed over time, the manner in which fire spread, and how patterns produced correlated to the origin of the fire. The fire was initiated on the driver’s side of the engine compartment and initially grew slowly with the high-temperature zone near the area of origin. Once the peak temperature reached about 540°C, the rate of flame spread increased such that over the next 4 minutes the fire spread across the entire engine compartment. In the next stage of the fire, which occurred shortly after full involvement of the engine compartment, the fire spread into the passenger compartment. A strong vertical temperature gradient developed from the ceiling to the floor and as the passenger compartment became fully involved, the passenger compartment temperatures both increased and became more uniform.
Technical Paper

Relationship Between Driver Eyes-Off-Road Interval and Hazard Detection Performance Under Automated Driving

2016-04-05
2016-01-1424
Abstract Partially automated driving involves the relinquishment of longitudinal and/or latitudinal control to the vehicle. Partially automated systems, however, are fallible and require driver oversight to avoid all road hazards. Researchers have expressed concern that automation promotes extended eyes-off-road (EOR) behavior that may lead to a loss of situational awareness (SA), degrading a driver’s ability to detect hazards and make necessary overrides. A potential countermeasure to visual inattention is the orientation of the driver’s glances towards potential hazards via cuing. This method is based on the assumption that drivers are able to rapidly identify hazards once their attention is drawn to the area of interest regardless of preceding EOR duration. This work examined this assumption in a simulated automated driving context by projecting hazardous and nonhazardous road scenes to a participant while sitting in a stationary vehicle.
Technical Paper

Subjective-Objective Ride Comfort Assessment of Farm Tractors

2016-04-05
2016-01-1437
Abstract The paper is focused on both the subjective and the objective ride comfort evaluation of farm tractors. The experimental measurement of the relevant accelerations occurring at the tractor body, at the cabin and at the seat was performed on a number of different farm tractors. A subjective rating of the ride comfort level was performed by considering five different drivers. The comfort index was computed according with ISO 2631 and other standards. The acceleration of the seated subject was computed by means of a proper mechanical model of a farm tractor and derived at different positions on the subject body. It turned out that the acceleration of the lower torso was particularly relevant for establishing a matching between the subjective perception and the objective measurement and computation. A number of indices have been derived from the measured data which are able to correlate the subjective driver feeling with the measured accelerations.
Technical Paper

Directivity Measurements of Low Frequency Sound Field Radiated from an Open Cylindrical Pipe with a Hot Mean Flow

2016-06-15
2016-01-1822
Abstract Radiation of sound from an open pipe with a hot mean flow presents one of the classic problems of acoustics in inhomogeneous media. The problem has been especially brought into focus in the last several decades, in the context of noise control of vehicle exhaust systems and jet engines. However, the reports on the measurements of the radiated sound field are still rare and scattered over different values of subsonic and supersonic flow speeds, cold and hot jets, as well as different sound frequency ranges. This paper focuses on low Mach number values of the mean flow speed and low frequencies of the incident (plane) sound waves inside an unflanged cylindrical pipe with a straight cut. It presents the results of the far-field radiation pattern measurements and compares them with an existing analytical model from the literature. The mean flow inside the pipe reached Mach number values up to 0.25 and temperature up to 300°C.
Technical Paper

Improving Acoustic Performance of an Air Filter Box. TL Analysis and Device Optimization

2016-06-15
2016-01-1813
Abstract The characteristics of the intake system affect both engine power output and gas-dynamic noise emissions. The latter is particularly true in downsized VVA engines, where a less effective attenuation of the pressure waves is realized, due to the intake line de-throttling at part-load. For this engine architecture, a refined air-box design is hence requested. In this work, the Transmission Loss (TL) of the intake air-box of a commercial VVA engine is numerically computed through a 3D FEM approach. Results are compared with experimental data, showing a very good correlation. The validated model is then coupled to an external optimizer (ModeFRONTIERTM) to increase the TL parameter in a prefixed frequency range. The improvement of the acoustic attenuation is attained through a shape deformation of the inner structure of the base device, taking into account constraints related to the device installation inside the engine bay.
Technical Paper

Simulation Study on Vehicle Road Performance with Hydraulic Electromagnetic Energy-Regenerative Shock Absorber

2016-04-05
2016-01-1550
Abstract This paper presents a novel application of hydraulic electromagnetic energy-regenerative shock absorber (HESA) into commercial vehicle suspension system and vehicle road performance are simulated by the evaluating indexes (e.g. root-mean-square values of vertical acceleration of sprung mass, dynamic tire-ground contact force, suspension deflection and harvested power; maximum values of pitch angle and roll angle). Firstly, the configuration and working principle of HESA are introduced. Then, the damping characteristics of HESA and the seven-degrees-of-freedom vehicle dynamics were modeled respectively before deriving the dynamic characteristics of a vehicle equipped with HESA. The control current is fixed at 7A to match the similar damping effect of traditional damper on the basis of energy conversion method of nonlinear shock absorber.
Journal Article

Modelling and Simulation of Rapidly Changing Road Gradients

2016-04-05
2016-01-1663
Abstract In vehicle dynamics modelling, the road profile is generally treated in one of two ways; either the gradient is a property that changes over a length scale far greater than that of the vehicle's wheelbase, or as a very detailed road surface model for determining the behaviour of vehicle suspensions. Occasionally, for modelling the behaviour of off-road vehicles, step-climbing manoeuvres are modelled. We propose an extension of these step-climbing models to a general, continuously varying road gradient model for cases where the distance over which the large gradient change occurs are of similar length-scale as the vehicle wheelbase. The motivation behind this work comes from a road gradient and vehicle mass estimation problem where it was noticed that very sudden gradient changes have a significant impact on the powertrain, but in a way that is not proportional to the attitude change of the vehicle.
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