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Technical Paper

Background and Technology Approach for Development and Testing of Auto-Tire Inflation System for Reducing Tire Wear in Commercial Vehicle

2018-04-03
2018-01-1341
Abstract The reduction of tire wear in vehicle is one of the major challenges for engineers. Under-inflated tire can cause reduction in tire life along with decrease in driving stability of vehicle. Efforts have been taken to develop a low-cost auto-tire inflation system integrated in vehicle for reduction in tire wear as well as to avoid periodic checks of tire pressure. This paper deals with the technology and design approach required in the development of auto-tire inflation system for commercial vehicle. This system should have the fundamental role of not only monitoring the tire pressure but also inflating the tire to the recommended level of pressure whenever the pressure is reduced below the recommended level. Different approaches have been worked out for integration of system on vehicle with least modification in existing design.
Technical Paper

Research on Regenerative Braking Control Strategy of Distributed EV based on Braking Intention

2018-04-03
2018-01-1342
Abstract Focusing on distributed electric vehicles with in-wheel motors, a novel regenerative braking control strategy based on braking intention is proposed. Firstly, a design scheme for the regenerative braking system is described. Four in-wheel motors and an Electro-Hydraulic Braking (EHB) system are respectively designed for regenerative braking and hydraulic braking. Then, Braking intention recognition self-learning libraries are trained based on Hidden Markov Model method, which is validated by driver-in-loop tests. According to three speed states and four braking intentions, the regenerative braking control strategy for multiple brake modes is developed. The coefficient of regenerative braking is defined to describe the intervening time and proportion of motor maximum regenerative braking.
Technical Paper

Parameter Identification for Combined Slip Tire Models using Vehicle Measurement System

2018-04-03
2018-01-1339
Abstract It is imperative to have accurate tire models when trying to control the trajectory of a vehicle. With the emergence of autonomous vehicles it is more important than ever before to have accurate models that represent exactly how the vehicle will operate in any situation. Many different types of tire models have been developed and validated, including physics based models such as brush models, black box models, finite element based models, and empirical models driven by data such as the magic formula model. The latter is widely acknowledged to be one of the most accurate tire models available however collecting data for this model is not an easy task. Collecting data is often accomplished through rigorous testing in a dedicated facility. This is a long and expensive procedure that will generally destroy many tires before a comprehensive dataset is acquired. Using a Vehicle Measurement System (VMS), tires can be modeled through on-road data alone.
Technical Paper

Active Tire Pressure Control (ATPC) for Passenger Cars: Design, Performance and Analysis of the Potential Fuel Economy Improvement

2018-04-03
2018-01-1340
Abstract Active Tire Pressure Control (ATPC) is an automatic central tire inflation system, designed, prototyped and tested at the Politecnico di Torino, which is aimed at improving the fuel consumption, safety and drivability of passenger vehicles. The pneumatic layout of the system and the designed solution for on-board integration are presented. The critical design choices are explained in detail and supported by experimental evidence. In particular, the results of experimental tests, including the characterizations of various pneumatic components in working conditions, have been exploited to obtain a design, which allows reliable performance of the system in a lightweight solution. The complete system has been tested to verify its dynamics, in terms of actuation time needed to obtain a desired pressure variation, starting from the current tire pressure, and to validate the design.
Technical Paper

Crushing Behavior of Vehicle Battery Pouch Cell and Module: A Combined Experimental and Theoretical Study

2018-04-03
2018-01-1446
Abstract Lithium-ion (Li-ion) batteries are considered as one of the solutions for electric vehicles (EV) in the automotive industry due to their lightweight and high energy density. Their mechanical performance is of great importance for electric vehicle crashworthiness design. In this study, quasi-static and dynamic indentation tests were conducted on commercially available vehicle battery pouch cells to investigate their structural integrity. Three indenters, namely a 19.1 mm (3/4 in) diameter flat end (FE), a 25.4 mm (1 in) diameter hemispherical (LH) and a 12.7 mm (1/2 in) diameter hemispherical (SH) were used to investigate the punch force - deflection responses of the cells. Loading velocity varied in the range of 0.06 mm/s to 3 m/s to test the strain rate effect. Simplified closed form analysis solutions were developed to predict the pouch cell force - deflection response by considering the effect of compression, tension and shear of the battery component materials.
Technical Paper

Stress Analysis on the Single-Lap SPR- Adhesive Hybrid Joint

2018-04-03
2018-01-1445
Abstract Self-pierced rivet (SPR) and adhesive are two important joining technologies widely used in automobile industry, and they are often used together to form a hybrid joint. SPR and adhesives can often be used in close proximity in a component, leading to an interaction of the two joints. This interaction can influence the corrosion and noise, vibration and harshness (NVH) characteristics of the structure, as well as its strength and durability. In this paper, the stress distribution in an SPR-adhesive hybrid joint is evaluated by using the finite element method, and then compared with that in an adhesive joint. Results indicate that the stress concentrates at the edge of adhesive layer in hybrid joint and adhesive joint and around the rivet in an SPR joint. The effect of rivet is numerically investigated by either removing the rivet from the hybrid joint or changing the position of the rivet on the overlapping area.
Technical Paper

Determination of Impact Responses of ES-2re and SID-IIs - Part III: Development of Transfer Functions

2018-04-03
2018-01-1444
Abstract An understanding of stiffness characteristics of different body regions, such as thorax, abdomen and pelvis of ES-2re and SID-IIs dummies under controlled laboratory test conditions is essential for development of both compatible performance targets for countermeasures and occupant protection strategies to meet the recently updated FMVSS214, LINCAP and IIHS Dynamic Side Impact Test requirements. The primary purpose of this study is to determine the transfer functions between the ES-2re and SID-IIs dummies for different body regions under identical test conditions using flat rigid wall sled tests. The experimental set-up consists of a flat rigid wall with five instrumented load-wall plates aligned with dummy’s shoulder, thorax, abdomen, pelvis and femur/knee impacting a stationary dummy seated on a rigid low friction seat at a pre-determined velocity.
Technical Paper

Evaluation of Engine-Related Restrictions for the Global Efficiency by Using a Rankine Cycle-Based Waste Heat Recovery System on Heavy Duty Truck by Means of 1D-Simulation

2018-04-03
2018-01-1451
Abstract As a promising concept to improve fuel efficiency of a long-haul heavy duty truck with diesel engine, organic Rankine cycle (ORC) based waste heat recovery system (WHR) by utilizing the exhaust gas from internal combustion engine has continuously drawn attention from industry in recent years. The greatest achievable global efficiency may be, however, restricted by the engine. On one hand, engine operating conditions have direct impact on the temperature and the mass flow of exhaust gas, which is the waste heat source, on the other hand, the engine cooling system limits the heat rejection from the condenser of the WHR system. This paper aims to evaluate the impacts of the varied engine applications considering the effects of the WHR system on the global efficiency and engine emissions.
Technical Paper

Real-Time Automatic Test of AEB with Brake System in the Loop

2018-04-03
2018-01-1450
Abstract The limitation of drivers' attention and perception may bring collision dangers, Autonomous Emergency Braking (AEB) can help drivers to avoid the potential collisions through active braking. Since the positive effect of it, motor corporations have begun to equip their vehicles with the system, and regulatory agencies in various countries have introduced test standards. At this stage, the actuator of AEB usually adopts Electronic Stability Program (ESP), but it poor performance of continuous working period and active pressure built-up for all wheels limits its implements. Electromechanical brake booster can realize power assisted brake without relying on the vacuum source and a variety of specific power curves. Moreover it can achieve the active braking with a rapid response, which make it can fulfill requirements of automotive electric and intelligent development.
Technical Paper

Determination of Impact Responses of ES-2re and SID-IIs – Part II: SID-IIs

2018-04-03
2018-01-1448
Abstract The main purpose of this study was to determine the impact responses of the different body regions (shoulder, thorax, abdomen and pelvis/leg) of the ES-2re and SID-IIs dummies using rigid wall impacts under different initial test conditions. The experimental set-up consisted of a flat rigid wall with five instrumented load-wall plates aligned with dummy’s shoulder, thorax, abdomen, pelvis and knee impacting a stationary dummy seated on a rigid seat at a pre-determined velocity. The relative location and orientation of the load-wall plates was adjusted relative to the body regions of the ES-2re and SID-IIs dummies respectively.
Technical Paper

Behavior of Adhesively Bonded Steel Double-Hat Section Components under Lateral Impact Loading

2018-04-03
2018-01-1447
Abstract Recent experimental studies on the behavior of adhesively-bonded steel double-hat section components under axial impact loading have produced encouraging results in terms of load-displacement response and energy absorption when compared to traditional spot-welded hat- sections. However, it appears that extremely limited study has been carried out on the behavior of such components under transverse impact loading keeping in mind applications such as automotive body structures subject to lateral/side impact. In the present work, lateral impact studies have been carried out in a drop-weight test set-up on adhesively-bonded steel double-hat section components and the performance of such components has been compared against their conventional spot-welded and hybrid counterparts. It is clarified that hybrid components in the present context refer to adhesively-bonded hat-sections with a few spot welds only aimed at preventing catastrophic flange separations.
Technical Paper

Full-Scale Burn Tests of Side-by-Side All-Terrain Vehicles

2018-04-03
2018-01-1437
Abstract Two full-scale burn tests involving identical side-by-side all-terrain vehicles were conducted to evaluate fire spread, changes in temperature distributions over time, and how burn patterns correlated to the known point of origin of the fires. The fires were initiated by igniting body panels at opposite corners of the vehicles such that in one test the fire propagated downwind and, in the other, it propagated upwind. In both tests, drop-down from the body panels onto the tires resulted in ignition of the tires. This was an important feature of the mechanism of fire spread. Once the tires began to burn, a transition occurred and the rate of fire spread to the remaining portion of the vehicle increased. Although the time between fire initiation and this transition was significantly different in the two tests, the time to spread and to consume the remaining combustibles within each vehicle was relatively consistent, independent of wind direction.
Technical Paper

Structural Designs for Electric Vehicle Battery Pack against Ground Impact

2018-04-03
2018-01-1438
Abstract Ground impact caused by road debris can result in very severe fire accident of Electric Vehicles (EV). In order to study the ground impact accidents, a Finite Element model of the battery pack structure is carefully set up according to the practical designs of EVs. Based on this model, the sequence of the deformation process is studied, and the contribution of each component is clarified. Subsequently, four designs, including three enhanced shield plates and one enhanced housing box, are investigated. Results show that the BRAS (Blast Resistant Adaptive Sandwich) shield plate is the most effective structure to decrease the deformation of the battery cells. Compared with the baseline case, which adopts a 6.35-mm-thick aluminum sheet as the shield plate, the BRAS can reduce the shortening of cells by more than 50%. Another type of sandwich structure, the NavTruss, can also improve the safety of battery pack, but not as effectively as the BRAS.
Technical Paper

High-Performance Rear- and Mid-Engine Vehicle Exhaust System Temperatures

2018-04-03
2018-01-1436
Abstract Hot surface ignition of combustible material is a known cause of vehicle fires. Although the detailed mechanisms of hot surface ignition are highly complex, the surface temperature is known to play a crucial role in this process. There has been limited previous work in the literature on this topic, much of which has focused on engine or exhaust system surface temperatures of the most common types of passenger vehicles. Also, much of this work was done in an unrepeatable manner and suffered from measurement technique induced errors. The focus of the present work is on repeatable and low measurement technique induced error temperature measurements of exhaust system surface temperatures of rear- and mid-engine sports cars. Temperature measurements were made at several points along the exhaust systems of vehicles both with and without turbo chargers on a 5-mile oval track.
Technical Paper

Study of Effects of Thermal Insulation Techniques on a Catalytic Converter for Reducing Cold Start Emissions

2018-04-03
2018-01-1431
Abstract Previous work done at the University of Michigan shows the capability of the vacuum-insulated catalytic converter (VICC) to retain heat during soak and the resulting benefits in reducing cold start emissions. This paper provides an improved version of the design which overcomes some of the shortcomings of the previous model and further improves the applicability and benefits of VICC. Also, newer materials have been evaluated and their effects on heat retention and emissions have studied using the 1-D after treatment model. Cold start emissions constitute around 60% to 80% of all the hydrocarbon and CO emissions in present day vehicles. The time taken to achieve the catalyst light-off temperature in a three-way catalytic converter significantly affects the emissions and fuel efficiency. The current work aims at developing a method to retain heat in catalytic converter, thus avoiding the need for light-off and reducing cold start emissions effectively.
Technical Paper

Accuracy of Speed Data Acquired from Ford Sync Generation 2 and Generation 3 Modules Utilizing the Berla iVe System

2018-04-03
2018-01-1442
Abstract Since 2007, when the first iPhone was released, the ability to sync smartphone data with vehicle infotainment systems has grown exponentially. Convenience in making calls and sending Short Message Service (SMS) messages from vehicles has been a driving force in the rapid expansion of services available in vehicle infotainment systems, and the data stored within these systems. Modern vehicles generally incorporate the user controls for these systems into touchscreen head units that may also include vehicle navigation services. As a result, the memory in these systems often stores user-supplied infotainment data (e.g., contact lists, call logs, SMS messages, etc.) as well as vehicle-generated telematics data (e.g., locations, track logs, velocity logs, etc.). The Berla iVe System can be used to acquire and analyze historical vehicle GPS location data from Ford Sync Generation 2 and Sync Generation 3 systems. Vehicle speed data is calculated from GPS location and time data.
Technical Paper

Full Scale Burn Demonstration of Two 2013 Ford Fusions - Arc Mapping Analysis

2018-04-03
2018-01-1439
Abstract Vehicle fire investigators sometimes use the existence and location of thermally damaged wiring (arced, shorted, melted, & beaded) discovered in a post burn analysis of a vehicle as an indication of the fire origin and its cause. One systematic method of analysis is to use the process of arc mapping. To examine the reliability of arc mapping in motor vehicle fires, two full scale burn demonstrations were conducted on 2013 Ford Fusions. Both vehicles had similar fire origins artificially initiated in the interior of the vehicles near the driver’s front seat. The engines were running and all accessories were off. During the burn sequence, occurrences of fire induced unintended electrical activity were captured with video and still photography. Examples of this unintended activity include lights, horn, wipers, and decklid latch activation. The burn concluded when the measured battery voltage went to zero in demonstration 1.
Technical Paper

Experimental Study of Lean Mixture Combustion at Ultra-High Compression Ratios in a Rapid Compression Machine

2018-04-03
2018-01-1422
Abstract In order to meet increasingly stringent fuel consumption and emission regulations, more attentions are paid to improve engine efficiency. A large amount of energy-saving technologies have been applied in automotive field especially in gasoline engines. It is well known that lean burn and ultra-high compression ratio technologies are two basic and important methods to increase efficiency. In this paper, a rapid compression machine was employed to study combustion process of lean iso-octane mixture at ultra-high compression ratios (16 to 19:1). Regardless of flammability of the mixture, spark was triggered at the timing right after the end of compression, then, the flame propagation and/or auto-ignition can be recorded using high-speed photography simultaneously. The effects of equivalence ratio (φ), compression ratio (ε), dilution ratio, and effective temperature (Teff) on the combustion process was investigated.
Technical Paper

Large Eddy Simulation of Stratified Combustion in Spray-guided Direct Injection Spark-ignition Engine

2018-04-03
2018-01-1420
Abstract Stratified combustion in gasoline engines constitutes a promising means of achieving higher thermal efficiency for low to medium engine loads than that achieved with combustion under standard homogeneous conditions. However, creating a charge that leads to a stable efficient low-emission stratified combustion process remains challenging. Combustion through a stratified charge depends strongly on the dynamics of the turbulent fuel-air mixing process and the flame propagation. Predictive simulation tools are required to elucidate this complex mixing and combustion process under stratified conditions. For the simulation of mixing processes, combustion models based on large-eddy turbulence modeling have typically outperformed the standard Reynolds averaged Navier-Stokes methods.
Technical Paper

Influence of Engine Speed and Injection Phasing on Lean Combustion for Different Dilution rates in an Optically Accessible Wall Guided Spark Ignition Engine

2018-04-03
2018-01-1421
Abstract Alternative combustion control in the form of lean operation offers significant advantages such as high efficiency and ‘clean’ fuel oxidation. Maximum dilution rates are limited by increasing instability that can ultimately lead to partial burning or even misfires. A compromise needs to be reached between high tumble-turbulence levels that ‘speed-up’ combustion, and the inherent stochastic nature of this fluid motion. The present study is focused on gaining improved insight into combustion characteristics through thermodynamic analysis and flame imaging, in a wall guided direct injection spark ignition engine with optical accessibility. Engine speed values were investigated in the range of 1000 to 2000 rpm, with commercial gasoline fueling, in wide open throttle conditions; mixture strength ranged from stoichiometric, down to the equivalence ratios that allowed acceptable cycle-by-cycle variations.
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