Browse Topic: Road tests

Items (188)

Performance Enhancement of Semi-active Continuous Skyhook Control Using Chaotic Map Particle Swarm Optimization-Based Stability Augmentation System

9/16/2022

Abstract Enhancing the performance of a ride-oriented algorithm to provide ride comfort and vehicle stability throughout different terrains is a challenging task. This article aims to improve the performance of the state-of-the-art continuous skyhook algorithm in coupled motion modes with an optimally tuned stability augmentation system (SAS). The tuning process is carried out using a chaotic map-initialized particle swarm optimization (C-PSO) approach with ride comfort and roll stability as a performance index. A large van model built-in CarSim is co-simulated with a C-PSO algorithm and control system designed in MATLAB. To realize the feasibility and effectiveness of the proposed system, a software-in-loop test is conducted on five complex ride terrains with different dominant vehicle body motion modes. The test results are compared against the passive system, four corner continuous skyhook control, and four corner type-1 fuzzy control. The test results confirm the effectiveness of the proposed system in providing better ride comfort, improved roll stability, good road holding, and eliminating the possibility of an untripped rollover. The results indicate a significant performance enhancement of CS-SAS against four corner continuous skyhook in ride road tests with an average root mean square (RMS) heave acceleration reduction of 28.41%. The results also exhibit distinct control effects on vehicle roll by mitigating the RMS-roll angle by an average of 61.52% for stability-based road tests.

Rajasekharan Unnithan, Anand Raj, Subramaniam, Senthilkumar

Simulation of Transient On-Road Conditions in a Closed Test Section Wind Tunnel Using a Wing System with Active Flaps

2020-01-06884/14/2020

Typical automotive research in wind tunnels is conducted under idealized, stationary, low turbulence flow conditions. This does not necessarily reflect the actual situation in traffic. Thus, there is a considerable interest to simulate the actual flow conditions. Because of this, a system for the simulation of the turbulence intensity I, the integral linear scale L and the transient angle of incidence β measured in full-scale tests in the inflow of a test vehicle was developed and installed in a closed-loop, closed test section wind tunnel. The system consists of four airfoils with movable flaps and is installed in the beginning of the test section. Time-series of the flow velocity vector are measured in the empty test section to analyze the system’s envelope in terms of the turbulence intensity and the integral length scales. It is shown that the length scales in spanwise and in driving (streamwise) direction can be varied from 0.15 m to 7.9 m and from 0.15 m to 2.5 m, respectively, depending on the frequency of the flap movement. The maximum obtained turbulence intensity in the driving direction x is 3% and in the spanwise direction y 9.8%, depending on the flap’s amplitude. It is further shown that the turbulence intensity in driving direction can be increased to 5.6% with passive turbulence generators. Additionally, a model for predicting the flap movement reproducing the transient angle of incidence β measured in the on-road tests during an overtaking maneuver was developed. Measurements of the forces acting on the vehicle revealed an influence of the non-stationary flow on the non-stationary force coefficients. Finally, changes of up to 0.002 in Δcd and 0.157 in Δcs were measured.

Wilhelmi, Henning, Jessing, Christoph, Bell, James, Heine, Daniela, Wagner, Andreas, Wiedemann, Jochen, Wagner, Claus

Performance Testing and Analysis of Multi-Channel Active Control System for Vehicle Interior Noise Using Adaptive Notch Filter

2019-01-15676/5/2019

It is considered that slow convergence speed and large calculation amount of commonly used adaptive algorithm in the active control system for vehicle interior noise yield noise reduction performance and hardware requirements problems. In this paper, a 4-channel active control of vehicle interior noise based on adaptive notch filter is established, and road test is carried out to test and analyze the performance of the control system. Firstly, the general mathematic model of the multi-channel active control system based on adaptive notch filter is established. The computational complexity of the algorithm is analyzed and compared with that of the FXLMS algorithm. Secondly, a hardware-in-the-loop test bench based on multi-channel adaptive notch filter is set up, to measure the noise reduction performance of ANC system under various working conditions. Finally, the typical test conditions are designed to test the system noise reduction performance, and the road test is carried out and result is analyzed.

Zhang, Lijun, Zhang, Xiyu, Meng, Dejian

Evaluation of Uncertainties in Classical and Component (Blocked Force) Transfer Path Analysis (TPA)

2019-01-15446/5/2019

Transfer path analysis (TPA) has become a widely used diagnostic technique in the automotive and other sectors. In classic TPA, a two-stage measurement is conducted including operational and frequency response function (FRF) phases from which the contribution of various excitations to a target quantity, typically cabin sound pressure, are determined. Blocked force TPA (also called in situ Source Path Contribution Analysis, in-situ TPA and component TPA) is a development of the classic TPA approach and has been attracting considerable recent attention. Blocked force TPA is based on very similar two stage measurements to classic TPA but has two major advantages: there is no need to dismantle the vehicle and the blocked forces obtained are an independent property of the source component and are therefore transferrable to different assemblies. However, despite the now widespread reliance on classic TPA, and the increasing use of blocked force TPA in the automotive sector, it is rare to see any evaluation of the associated uncertainties. This paper therefore aims to summarize recent work and provide a guide to the evaluation of uncertainties in both forms of TPA. The various types of uncertainty are first categorized as, ‘model’, ‘source’ and ‘experimental’ uncertainties. Model uncertainties arise due to incomplete or inconsistent representation of the physical assembly by the measurements. Criteria are provided for evaluation of completeness in terms of measured quantities. Experimental and source uncertainties are evaluated through a first order propagation approach. Expressions are provided allowing the uncertainty in the target quantity to be estimated from measured quantities. Additional data storage and analysis is required but no additional measurements are needed over and above the usual TPA measurements. An illustrative example is provided.

Moorhouse, Andy, Meggitt, Joshua, Elliott, Andrew

A Case Study on Golf Car Powertrain NVH Sources and Mitigation Methods

2019-01-14786/5/2019

The golf market has remained flat in North America. Whereas, it has grown worldwide. A trend is seen where the number of young adults and adults over the age of 65 years involved with the game has increased. The demographics in golf showing the most growth also have high standards for the operation of the golf car. They have transcended their expectations to align with some of the qualities expected of automobiles. There is a shift in consumer expectations. Moreover, the market competition has also increased. This drives the OEMs to deliver refined golf cars with NVH being a key aspect in development. This paper showcases a recent study to improve the powertrain N&V performance of an internal combustion engine golf car. Primarily, a test-based approach is followed. Chassis rolls and on road testing are performed for benchmarking and target setting. System and component tests are performed to root cause issues. The tests further help to provide input for mitigation methods for application on the golf cars. Structural modifications address structure-borne noise and perceived vibration. Component modifications and additions address three key aspects. They reduce air-borne noise, decrease overall SPL, and improve sound quality for brand identity. These mitigation techniques are applied on the golf car. Jury evaluations correlated with on-road testing results for golf car improvement. The improvements were in both sound quantity and sound quality.

Carter, Steven, Buczek, Kenneth, Clark, Adam, Pathak, Mayuresh

Reducing Vehicle Interior NVH by Means of Locally Resonant Metamaterial Patches on Rear Shock Towers

2019-01-15026/5/2019

Stringent regulations for CO2 emissions and noise pollution reduction demand lighter and improved Noise, Vibration Harshness (NVH) solutions in automotive industries. Designing light, compact and, at the same time, improved NVH solutions is often a challenge, as low noise and vibration levels often require heavy and bulky additions, especially to be effective in the low frequency regime. Recently, locally resonant metamaterials have emerged among the novel NVH solutions because of their performant NVH properties combined with lightweight and compact design. Due to the characteristic of stop band behavior, frequency ranges where free wave propagation is inhibited, metamaterials can beat the mass law, be it at least in some tunable frequency ranges. Previously the authors demonstrated how metamaterials can reduce the vibrations in a simplified shock tower upon shaker excitation. In this work, the authors apply the metamaterial concept on the real rear shock towers of a vehicle. In order to be able to benchmark the solution, a test vehicle is chosen, which is equipped in its commercial version with a 1.46 kg tuned vibration absorber (TVA) on each of the rear shock towers as NVH solution. It is shown that the metamaterial solution allows to achieve similar interior NVH performance, while reducing the added mass by 48%. The metamaterial additions are realized through additive manufacturing and they are designed to be effective around 190 Hz, as was the case for the original solution. Both experimental results and numerical validation of a road test are presented.

Sangiuliano, Luca, Claeys, Claus, Deckers, Elke, De Smet, Jasper, Pluymers, Bert, Desmet, Wim

‘Road Race’ for AV Testing May Be Slowing

19AVEP05_105/1/2019

To optimize safety, as well as cost- and time-efficiency, experts espouse increased virtual testing of autonomous vehicles as preferable to the industry's rush to test on public roads. Chris Hoyle, technical director of software specialist rFpro, believes the race by auto and technology companies to be ahead of competitor programs involving autonomous vehicle (AV) testing on public roads is losing momentum. “This trend follows reports of autonomous vehicles being involved in fatal accidents. Now there is more competition to deliver the highest level of validation before a vehicle turns a wheel on the highway. This re-alignment of priorities is good news for all parties because it will accelerate improvements in AV safety,” Hoyle asserted.

Fine Tuning the SST k − ω Turbulence Model Closure Coefficients for Improved NASCAR Cup Racecar Aerodynamic Predictions

2019-01-06414/2/2019

Faster turn-around times and cost-effectiveness make the Reynolds Averaged Navier-Stokes (RANS) simulation approach still a widely utilized tool in racecar aerodynamic development, an industry where a large volume of simulations and short development cycles are constantly demanded. However, a well-known flaw of the RANS methodology is its inability to properly characterize the separated and wake flow associated with complex automotive geometries using the existing turbulence models. Experience suggests that this limitation cannot be overcome by simply refining the meshing schemes alone. Some earlier researches have shown that the closure coefficients involved in the RANS turbulence modeling transport equations most times influence the simulation prediction results. The current study explores the possibility of improving the performance of the SST k − ω turbulence model, one of the most popular turbulence models in motorsports aerodynamic applications, by re-evaluating the values of certain model closure constants. A detailed full-scale current generation NASCAR Cup racecar was used for the investigation. The simulations were run using a commercial CFD package STAR-CCM+ (version 13.04.010). Five different closure coefficients in the SST k − ω model, σk1, σk2, σω1, σω2 and β∗, were examined. The investigation suggests the influence of each closure coefficient on the simulation prediction results are significantly different. β∗ appeared to be the most sensitive closure coefficient whereas both σk1 and σk2 had almost no effect on the NASCAR Cup racecar aerodynamic predictions. This study proposes a new set of SST k − ω turbulence model closure coefficients which has the potential of providing better-correlated aerodynamic predictions of a NASCAR Cup racecar under a range of different operating conditions.

Fu, Chen, Bounds, Charles, Uddin, Mesbah, Selent, Christian

19AVEP03_113/1/2019

Transportation-infrastructure expert Kirk Steudle reflects on the rapid progress toward the connected-AV future and the challenges ahead. In the auto industry, mechanical and electrical engineers work from the tire up. Civil engineers work from the tire down,” quips Kirk Steudle. “And although it's taken a while for both to understand each other's jargon, the connected-and-autonomous vehicle is forcing them all together-to solve problems for society's mobility.” Steudle, a registered professional engineer, has been at the vehicle-to-road nexus his entire career. Last October he retired as director of the Michigan Dept. of Transportation where, among many achievements, his leadership helped put the state and its core industry in the vanguard of connected-car and AV-related developments, testing, and infrastructure standards. During his final year at MDoT, he also served as interim CEO of the American Center for Mobility, the new 500-acre AV proving ground and test center near Ann Arbor.

Brooke, Lindsay

Introduction to Autonomous Trucking and Platooning Technology

C191312/19/2018

Vehicle automation and intelligent transportation systems will be the cornerstones of sustainable smart cities of the future. People movers seem to be at the heart of technology development, field trials and on-road testing, and strategic business partnerships when it comes to connectivity and automated driving. Majority of the focus has been on unmanned operation and door-to-door service in urban environments and not on highways. Highways are relatively simpler to handle from an engineering stand-point, but vehicles typically operate at higher speeds, so the cost of accidents is worse. This is very applicable for Class 8 trucks that are hauling loads (i.e., heavy), big, and fast. At the same time, most of the truck maneuvering, especially on highway is pretty straightforward (i.e., maintaining a highway lane, usually the slowest one, with limited lane change maneuvers). It is also easy to contemplate how automating buses (where the routes are fixed) or construction equipment (in confided areas) make sense from a safety and economics point-of-view. This leads to the “Heavy metal first” hypothesis, where we explore why automation in the heavy-duty sector and industrial machines may happen sooner. Some truck OEMs and technology companies have been exploring truck automation. While some have explored concepts such as truck platooning (automated driving with a human in the cab), others have been testing fully autonomous trucks in customer operations. This course is intended to cover the basics of connected automation and provide a ringside view of everything happening in the area of truck automation with special focus on platooning including, but not limited to technology development, field trials, opportunities, and challenges facing the wide scale deployment of such systems.By attending this seminar, you will be able to: Recognize application scenarios for platooning to trucks and buses Appreciate the synergy between connectivity and automated driving systems Gain a solid understanding of the relationship between the different levels of vehicle automation Develop the ability to appreciate the impacts of automation on existing business operations Identify the complications with safely introducing automation on public roads 2 Days CEUs

Cementitious-Based Brake Pads Technology: Performance, Low Energy Consumption, Emission Drop

2018-01-186710/5/2018

Brake pads employing innovative hydraulic inorganic binders in place of common state-of-the-art thermosetting phenolic resins have been produced by means of a unique prototypal equipment and a distinctive manufacturing process. The unicity of the process enables us to exclude completely any thermal cycle in the manufacturing steps, with a considerable positive energy balance compared to the standard counterpart. Realized brake pads have indeed been successfully tuned to meet the braking performances of phenolic counterparts. In the present work our latest efforts in this field are illustrated, focusing our attention to three main areas of interest: performance, energy consumption, volatile organic emissions. One selected exponent of our cementitious-based material is reported, demonstrating its capability of matching both standard OE and AM braking performances (investigated through a full scale brake dynamometer by SAE J2522 procedure), and its feasibility to be released as an actual AM material according to ECE R90 regulation (road test on vehicle). The energetic evaluation of the employed technology in term of prototypal manufacturing process and employed raw materials has been established, demonstrating the advantages of this new system compared to the standard one. Our investigation finally reports selected thermo-chemical analysis (TG-EGA and pyrolysis PY-GC/MS) devoted at identifying the key organic compounds potentially/eventually emitted during braking at various temperatures. Our material shows a dramatic drop of the volatile hazardous/organic compounds (VHCs/VOCs) released by a standard phenolic homologous, thus increasing the favorable characteristics of such inorganic hydraulic-binder brake pads and related technology.

Sanguineti, Alessandro, Samela, Alessandro, Rampinelli, Flavio, Bottalico, Luca, Ranza, Luigi, Romeo, Marco, Bonfanti, Andrea

Correlation of Objective and Subjective Evaluation in Automotive Brake Pedal Feel

2018-01-188910/5/2018

In order to establish the correlation between objective and subjective evaluation of brake pedal feel for passenger cars, road tests of brake pedal feel were carried out and an evaluation method was proposed. In the road tests, subjective scores and objective measurements were obtained under the conditions of uniform and emergency braking. The objective measurements include pedal preload, low deceleration pedal force and travel, moderate deceleration pedal force and travel, brake response time and brake linearity. Using the theory of analytic hierarchy process (AHP), the design process of the evaluation method was established. Key setups including the hierarchical structure model, the judgement matrix and the score calculation method of objective measurements were described in detail. Then, the correlation between subjective and objective scores was analyzed. It can be concluded that the evaluation method is effective and it can be applied to brake pedal feel assessment and adjustment.

Zhang, Jingyi, Meng, Dejian, Liu, Jialin

Investigation of a Cylinder Activation Concept for a Turbocharged Direct-Injection Gasoline Engine

2018-01-17139/10/2018

Today, downsizing through active displacement control is in series production using cylinder deactivation (CDA) concepts. However, current systems deactivating two cylinders of a four-cylinder engine are limited regarding the effective CO2 saving potential due to the confined usable operating range of the two-cylinder mode. Therefore, the objective of the current investigation is a three-cylinder engine with the possibility to activate an additional (fourth) cylinder. For this purpose, a four-cylinder series engine was modified to the firing order of a three-cylinder engine for the first three cylinders. The exterior cylinders 1 and 4 are operated in parallel, with the fourth cylinder deactivated in efficiency mode. Launching and idle mode are also operated with three active cylinders. Additional modifications to the valve train were carried out in order to further exploit the increased residual gas tolerance due to the load point shift. The increased ignition intervals, in conjunction with a very late intake closing timing (Atkinson cycle), improve the boundary conditions with respect to knocking tendency and lead to fuel saving potential even in the higher load range. This extends the map range of the efficiency mode up to full load in three-cylinder operation and therefore doubles the usable range compared to a conventional deactivation concept. The fourth cylinder is activated only when the maximum nominal power is required. In this operating mode, the load of the fourth cylinder can be continuously increased by the use of a fully variable valve train as an activation element. This activation strategy was simulated with a detailed 1d-simulation model. Based on the measurement data, simulation models of the original and the modified engine with a calibrated predictive combustion model have been set up. Using this simulation environment, both concepts were compared in a “virtual test drive” under the same boundary conditions.

Schurr, Anton, Guenthner, Michael, Flierl, Rudolf, Woike, David, Mueller, Florian

On-Road Monitoring of Low Speed Pre-Ignition

2018-01-16769/10/2018

To meet increasingly stringent emissions and fuel economy regulations, many Original Equipment Manufacturers (OEMs) have recently developed and deployed small, high power density engines. Turbocharging, coupled with gasoline direct injection (GDI) has enabled a rapid engine downsizing trend. While these turbocharged GDI (TGDI) engines have indeed allowed for better fuel economy in many light duty vehicles, TGDI technology has also led to some unintended consequences. The most notable of these is an abnormal combustion phenomenon known as low speed pre-ignition (LSPI). LSPI is an uncontrolled combustion event that takes place prior to spark ignition, often resulting in knock, and has been known to cause catastrophic engine damage. LSPI propensity depends on a number of factors including engine design, calibration, fuel properties and engine oil formulation. Several engine tests have been developed within the industry to better understand the phenomenon of LSPI. While data from these tests have greatly increased the industry’s knowledge about LSPI, they may not accurately represent LSPI as it occurs while the vehicle is in actual service. This is because the industry tests are conducted on highly controlled engine dynamometers, often using special calibrations. In this work, a vehicle is fully instrumented with a high-speed data acquisition system to monitor LSPI. The vehicle is then operated on public roads with commercially available, pump gasoline for approximately 65,000 miles (104,607 km). Results indicate that LSPI, as it occurs in real world vehicle use, shows some similarities and differences from LSPI that occurs in laboratory engine tests. Additionally, the transient nature of the on-road testing presented a significant departure from the steady-state engine laboratory testing. This difference necessitates the development of a new method for identifying LSPI cycles in real world environments. Finally, results from this work will help the industry develop solutions to LSPI which are effective in the field.

Michlberger, Alexander, Sutton, Mike, Kocsis, Michael, Anderson, Garrett, Van Horn, Adam

Determining Off-cycle Fuel Economy Benefits of 2-Layer HVAC Technology

2018-01-13684/3/2018

This work presents a methodology to determine the off-cycle fuel economy benefit of a 2-Layer HVAC system which reduces ventilation and heat rejection losses of the heater core versus a vehicle using a standard system. Experimental dynamometer tests using EPA drive cycles over a broad range of ambient temperatures were conducted on a highly instrumented 2016 Lexus RX350 (3.5L, 8 speed automatic). These tests were conducted to measure differences in engine efficiency caused by changes in engine warmup due to the 2-Layer HVAC technology in use versus the technology being disabled (disabled equals fresh air-considered as the standard technology baseline). These experimental datasets were used to develop simplified response surface and lumped capacitance vehicle thermal models predictive of vehicle efficiency as a function of thermal state. These vehicle models were integrated into a database of measured on road testing and coupled with U.S. typical meteorological data to simulate vehicle efficiency across seasonal thermal and operational conditions for hundreds of thousands of drive cycles. Fuel economy benefits utilizing the 2-Layer HVAC technology are presented in addition to goodness of fit statistics of the modeling approach relative to the experimental test data.

Jehlik, Forrest, Chevers, Netsanet, Moniot, Matthew, Song, Yuanpei, Hirabayashi, Hidekazu, Nomura, Masahiro, Wood, Eric

Utilization of ADAS for Improving Performance of Coasting in Neutral

2018-01-06034/3/2018

It has been discussed in numerous prior studies that in-neutral coasting, or sailing, can accomplish considerable amount of fuel saving when properly used. The driving maneuver basically makes the vehicle sail in neutral gear when propulsion is unnecessary. By disengaging a clutch or shifting the gear to neutral, the vehicle may better utilize its kinetic energy by avoiding dragging from the engine side. This strategy has been carried over to series production recently in some of the vehicles on the market and has become one of the eco-mode features available in current vehicles. However, the duration of coasting must be long enough to attain more fuel economy benefit than Deceleration Fuel Cut-Off (DFCO) - which exists in all current vehicle powertrain controllers - can bring. Also, the transients during shifting back to drive gear can result in a drivability concern. The in-neutral coasting system should automatically shift to drive in case of nearby traffic for safe operation capability. To mitigate those issues, this paper proposes an in-neutral coasting control algorithm that utilizes information from Advanced Driver Assistance System (ADAS). By monitoring driving condition ahead, such as distance and relative velocity to preceding vehicle, the algorithm can identify the appropriate coasting opportunity. The developed logic has been implemented in a test vehicle for validation and showed promising performance. The on-road test results and fuel economy analysis are presented with the description of the coasting algorithm.

Lee, Hoon, Lee, Jaihyun, Yoo, Sanghoon, Jeong, Kwangwoo, Lee, Byungho, Kim, Sejun, Guvenc, Levent, Cantas, Mustafa Ridvan, Tamilarasan, Santhosh, Chandramouli, Nitish

Impacts of Drive Cycle and Ambient Temperature on Modelled Gasoline Particulate Filter Soot Accumulation and Regeneration

2018-01-09494/3/2018

Gasoline particulate filters (GPF) are used as an efficient solution to reduce particulate matter (PM) emissions on gasoline vehicles. GPFs are ceramic wall-flow filters and are normally located downstream of conventional three-way catalysts (TWC) [1]. The study in this paper is intended to evaluate the impact of drive cycle and ambient temperature on modelled GPF soot accumulation and regeneration. The test data were obtained through real road testing in Chinese cities including Nanjing, Hainan and Harbin. Five 2.0 L gasoline turbo direct-injection (GTDI) prototype vehicles from several China Stage 6 applications were employed for the road tests. The results of the testing indicated that a drive cycle with low engine speed and engine load, like a typical city road in rush hour traffic in Nanjing, had a low probability of generating high GPF temperatures (> 600 °C) and sufficient oxygen to regenerate the GPF. However, the soot accumulation model performed as expected [2] and the soot regeneration model demonstrated sufficient opportunity to oxidize soot prior to excessive soot accumulation, even under the limited city drive cycle conditions. Ambient temperatures during cold engine starts played a significant role in the amount of modeled soot being generated during any given drive cycle. Considerably more soot was generated during cold starts at low ambient conditions (< 0 °C) due to the increase in fuel mass and the use and duration of compression injection to aid in catalyst heating.

Yue, Hongchao, Lehmen, Allen, Van Nieuwstadt, Michiel, Mason, Gregory, Barwick, Matt, Warm, David, Pebley, Kirk

Automotive Engineering: March 2018

18AUTP033/8/2018

Truck Tech War! Ford, GM, and Ram arm their profit-pumping half-ton pickups for the 2020s' efficiency battle. Mobility mecca: WCX 2018 Provocative thought leaders, emerging disruptors, and the industry's best networking and career guidance all under one big roof: the 2018 SAE World Congress Experience is coming April 10-12. Mercedes adopts Harman UX for A-Class The 'smart' architecture is capable of OTA updates and features more-accurate voice recognition. Spark of genius Mazda's Skyactiv-X-the nexus of gasoline and diesel tech-remains on track for 2019 production. We test-drive recent prototypes to check development status. Taking aim at the drowsy-driver threat Hyundai Mobis is leveraging Level 4 tech to move 'departed' drivers safely off the road. Editorial: Fear and loathing on the path to Level 4 driving Supplier Eye Variability, risk and the value stream The Navigator How will automated vehicles deal with potholes? SAE Standards News SAE-ISO Joint Working Group engaged in SAE J3061 revision Magna's new active airdam boosts 2019 Ram fuel efficiency Saving EV transmission energy and costs Autonomous vehicle cabins depart from traditional interior designs New California ZEV mandate simpler but more challenging, starting this year What We're Driving

Joint Effects Targeting System

TBMG-2795112/1/2017

U.S. Army Operational Test Command Fort Hood, TX 254-287-9993

Portable Emissions Measurement System for Solid Particle Number Including Nanoparticles Smaller than 23 nm

2017-01-240210/8/2017

Fine particle emissions from engine exhaust have attracted attention because of concern of their higher deposition fraction in alveoli. Since it was observed that sizes of solid particles in exhaust of conventional internal combustion engine technologies are mainly distributed above 30 nm and the mainly irreproducible sensitivity to volatile particles can be reduced, the current solid particle number (PN) measurement methodology was targeted to PN emissions particles larger than 23 nm. The necessity of the measurement of particles smaller than 23 nm is now under discussion. It is also surmised that there is difference between emissions under regulatory defined test cycles and real driving conditions. Currently, implementation of further real driving emission regulations utilizing portable emissions measurement systems (PEMS) is in place for the EU and being actively discussed in other regions. In this study, a commercially available PEMS for PN was modified to extend the detection limit to particles below 23 nm and its feasibility to on-board testing was investigated by performing measurement system performance checks, correlation exercises with a laboratory instrument and on-road tests. The application of condensation particle counter methodology was able to adjust the lower detection efficiency and ideal to determine the PN concentration due to the existence of a plateau region of detection efficiency over a sufficiently large range of particle sizes. A heated catalytic stripper improved volatile particle removal performance and prevented re-nucleation of volatile fractions at the particle counter. One of the technical challenges was higher particle losses below 23 nm.

Otsuki, Yoshinori, Tochino, Shigemi, Kondo, Kenji, Haruta, Kazuhiko

Systematic Experimental Creep Groan Characterization Using a Suspension and Brake Test Rig

2017-01-24889/17/2017

Vehicle road tests are meaningful for investigations of creep groan noise. However, problems in reproducing experiments and partly subjective evaluations may lead to imprecise conclusions. This work proposes an experimental test and evaluation procedure which provides a precise and objective assessment of creep groan. It is based on systematic corner test rig experiments and an innovative characterization method. The exemplary setup under investigation consisted of a complete front wheel suspension and brake system including all relevant components. The wheel has been driven by the test rig’s drum against a brake torque. The main parameters within a test matrix were brake pressure and drum velocity. Both have been varied stepwise to scan the relevant operating range of the automobile corner system for potential creep groan noise. Additionally, the experiments were extended to high brake pressures, where creep groan cannot be observed under road test conditions. The measurements with creep groan showed vibration characteristics of a non-linear stick-slip effect, particularly at high brake pressures. A novel method to detect and evaluate creep groan events within a large number of systematic measurements has been developed and tested. It uses the characteristic patterns of acceleration signals which are analyzed in the frequency domain. The main evaluation results are displayed collectively in multi-dimensional maps. Such Creep Groan Maps (CGM) show vibration intensity levels and relevant frequencies in dependence of brake pressure and drum velocity. An overall Creep Groan Index (CGI) scores the groaning tendency of a whole setup by a single number. Its calculation is based on the acceleration signals across the observed test matrix as well. CGM and CGI both allow a simple and objective comparison of different mechanical and/or tribological setups as well as parameter influence studies.

Pürscher, Manuel, Fischer, Peter

A Subjective Evaluation Method for Sound Insulation of Vehicle Body in Reverberation Room and an Objective Prediction Model

2017-01-18866/5/2017

A subjective evaluation method for the air-borne sound insulation of vehicle body in reverberation room is developed and the correlation between the subjective preference and objective noise reduction level (NRL) is investigated in this paper. The stationary vehicle's interior noise is recorded by using a digital artificial head under a given white noise excitation in the reverberation room, which demonstrates more credible than those in traditional road test methods. The recorded noises of six different vehicles are replayed and evaluated subjectively by 22 appraisers in a sound quality room. The paired comparison scoring method is employed and the check and statistic methods for the subjective scores are introduced. The subjective preference is introduced and calculated by the statistics and normalization of the effective scores, which can indicate an overall preference ranking of all the six vehicles numerically. Furthermore, an objective prediction model is established based on the correlation analyses and linear regressions. The subjective preference is proved to be attributed to the average NRL in 2k-5kHz frequency range only. The subjective evaluation method and the prediction model provide the guidance for the evaluation, prediction, target setting and optimization of the vehicle sound insulation.

Zhang, Siwen, Pang, Jian, Zhang, Jun, Ma, Zhuangzhuang, Zhang, Xiaoxuan, Liu, Congguang, Deng, Lihui

Using the Modal Response of Window Vibrations to Validate SEA Wind Noise Models

2017-01-18076/5/2017

The SEA model of wind noise requires the quantification of both the acoustic as well as the turbulent flow contributions to the exterior pressure. The acoustic pressure is difficult to measure because it is usually much lower in amplitude than the turbulent pressure. However, the coupling of the acoustic pressure to the surface vibration is usually much stronger than the turbulent pressure, especially in the acoustic coincidence frequency range. The coupling is determined by the spatial matching between the pressure and the vibration which can be described by the wavenumber spectra. This paper uses measured vibration modes of a vehicle window to determine the coupling to both acoustic and turbulent pressure fields and compares these to the results from an SEA model. The interior acoustic intensity radiating from the window during road tests is also used to validate the results.

DeJong, Richard, Ebbitt, Gordon

Analysis and Adaptive Estimation of Human Car Following Behavior for Advanced Driver Assistance Systems

2017-01-00443/28/2017

In the field of advanced driver assistance systems (ADAS) the capability to accurately estimate and predict the driving behavior of surrounding traffic participants has shown to enable significant improvements of the respective ADAS in terms of economy and comfort. The interaction between the different participants can be an important aspect. One example for this interaction is the car following behavior in dense urban traffic situations. There are different phenomenological or psychological models of human car following which also consider variations between different participants. Unfortunately, these models can seldom be applied for control directly or prediction in vehicle applications. A different way is to follow a control oriented approach by modeling the human as a time delay controller which tracks the inter-vehicle distance. The parameters are typically chosen based on empirical rules and do not consider variations between drivers. In this work a time delay controller approach is applied and extended. First real world measurements in urban test drives are recorded by a test vehicle equipped with forward and reward radar sensors. These datasets are analyzed and used to identify the varying parameters and their probability distribution functions for different human drivers. An advantage of the applied model structure is that it makes online learning and adaptation during the driving possible. This allows adapting prediction models during real world drives even in closed loop control and hence improves the prediction quality. Further, the identified driver models can be used to establish virtual multi vehicle scenarios and build up a virtual traffic environment. The obtained prediction results for different test drives show satisfactory results and could well capture the differences between drivers.

Schmied, Roman, Obereigner, Gunda, Waschl, Harald

Model Based Control of a Three-way Catalytic Converter Based on the Oxygen Storage Level of the Catalyst

2017-01-09603/28/2017

Traditionally, a three-way catalyst (TWC) is controlled to a set heated exhaust gas oxygen (HEGO) sensor voltage (typically placed after the monitored catalyst) that corresponds to optimal catalyst efficiency. This limits the control action, as we rely on emissions breakthrough at the HEGO sensor to infer the state of catalyst. In order to robustly meet the super ultra-low emission regulations, a more precise TWC control around the oxidation level of catalyst is desirable. In this work, we developed a comprehensive set of models to predict the oxygen storage capacity using measured in-vehicle signals only. This is accomplished by developing three models; the first model is a linear in parameter regression model to predict the feed gas emissions from measured signals like engine speed and air-to-fuel ratio (A/F). The second model is a low-dimensional physics based model of the three-way catalyst to predict the exhaust emissions and oxidation state of the catalyst. The third model computes the tailpipe A/F as a function of the exhaust emissions. These models were implemented and validated in vehicle using a rapid prototyping tool such as ATI NoHooks and validated over multiple FTP cycles and road tests. Finally, these models were used to design an outer-loop catalyst control (proportional-integral (PI) controller with an anti-windup loop) designed to achieve the desired fractional oxidation state (FOS) or the oxygen storage level. The experimental results confirm that the system is controllable and show improvement in catalyst control by reducing tail pipe emissions compared to current production strategy.

Kumar, Pankaj, Makki, Imad

Aerodynamic Drag of a Vehicle and Trailer Combination in Yaw

2017-01-15403/28/2017

Typical production vehicle development includes road testing of a vehicle towing a trailer to evaluate powertrain thermal performance. In order to correlate tests with simulations, the aerodynamic effects of pulling a trailer behind a vehicle must be estimated. During real world operation a vehicle often encounters cross winds. Therefore, the effects of cross winds on the drag of a vehicle–trailer combination should be taken into account. Improving the accuracy of aerodynamic load prediction for a vehicle-trailer combination should in turn lead to improved simulations and better thermal performance. In order to best simulate conditions for real world trailer towing, a study was performed using reduced scale models of a Sport Utility Vehicle (SUV) and a Pickup Truck (PT) towing a medium size cargo trailer. The scale model vehicle and trailer combinations were tested in a full scale wind tunnel. Utilizing a full scale wind tunnel allowed for very low blockage conditions and testing at large yaw angles by placing both the vehicle and the trailer entirely on the wind tunnel turntable and balance. This unique setup allowed for the measurement of all aerodynamic forces and moments on the vehicle, which could be used to improve vehicle dynamics modeling of a vehicle-trailer combination. The results of this paper show that the forces and moments on a vehicle-trailer combination change significantly at large yaw angles, and that zero yaw testing may be insufficient to predict the real world aerodynamic performance.

Lopes, Yuri M., Taylor, Maxwell R., Lounsberry, Todd H., Fadler, Gregory J.

Bayesian Parameter Estimation for Heavy-Duty Vehicles

2017-01-05283/28/2017

Accurate vehicle parameters are valuable for design, modeling, and reporting. Estimating vehicle parameters can be a very time-consuming process requiring tightly-controlled experimentation. This work describes a method to estimate vehicle parameters such as mass, coefficient of drag/frontal area, and rolling resistance using data logged during standard vehicle operation. The method uses a Monte Carlo method to generate parameter sets that are fed to a variant of the road load equation. The modeled road load is then compared to the measured load to evaluate the probability of the parameter set. Acceptance of a proposed parameter set is determined using the probability ratio to the current state, so that the chain history will give a distribution of parameter sets. Compared to a single value, a distribution of possible values provides information on the quality of estimates and the range of possible parameter values. The method is demonstrated by estimating dynamometer parameters. The results confirm the method’s ability to estimate reasonable parameter sets, and indicate an opportunity to increase the certainty of estimates through careful selection or generation of the test drive cycle.

Miller, Eric, Konan, Arnaud, Duran, Adam

The Study on Fatigue Test of Cab Assembly Based on 4-Channel Road Simulation Bench

2017-01-03283/28/2017

The multi-body dynamics simulation and physical iteration were carried out based on the 4-channel road simulation bench, the solution of fatigue test bench which was suitable for cab with frame and suspension was designed. Large load and displacement above the suspension can be loaded on the test bench, and the same weak position of cab exposed on the road test can be assessed well on the fatigue test bench. The effectiveness of the bench test solution was verified though comparative study. And it has important reference for the same type of cab assembly with suspension in the fatigue bench test. According to the durability specifications of cab assembly, a multi-body dynamics model with a satisfactory accuracy was built. And the fixture check and virtual iteration analysis were used to verify the effectiveness of the solution. According to the road load signal analysis and multi-body dynamics analysis results, the test bench with linear guide and spherical joint was built. In order to get the driving signals of cylinders, the acceleration signals beside the suspension were used as the target signals for physical iteration. The best test bench solution is the linear guide installed on the back and the spherical joint installed on the bottom of front cylinders through comparing three different iteration result of test bench solution. As a result, after completing 11 different road sections of iterations, the RMS error of target signal substantially was less than 13%. In order to simulate the actual condition, the driving signals obtained by physical iteration were used to drive the cylinder. Through comparative study, the test results of fatigue bench test and proving ground test has a highly consistency in terms of the damage distribution. Through the secondary development of 4-channel road simulation bench, it is efficient and accurate to assess the durability performance of the cab assembly with suspension. And it also provides guidance for developing and designing a test bench of functional diversification.

Gao, Yunkai, Wang, Genhai, Han, Jingpeng

Vehicle Lane Change Automation with Active Steering - Theoretical Studies and Numerical Investigations

2017-01-15553/28/2017

Lane change automation appears to be a fundamental problem of vehicle automated control, especially when the vehicle is driven at high speed. Selected relevant parts of the recent research project are reported in this paper, including literature review, the developed models and control systems, as well as crucial simulation results. In the project, two original models describing the dynamics of the controlled motion of the vehicle were used, verified during the road tests and in the laboratory environment. The first model - fully developed (multi-body, 3D, nonlinear) - was used in simulations as a virtual plant to be controlled. The second model - a simplified reference model of the lateral dynamics of the vehicle (single-body, 2D, linearized) - formed the basis for theoretical analysis, including the synthesis of the algorithm for automatic control. That algorithm was based on the optimal control theory. The algorithm includes the determination of time optimal reference profiles defining control input and vehicle response (the reference steering wheel angle of the "bang-bang" type). Implementation of the prescribed motion trajectory in the control system is made using Kalman regulators ensuring optimal trajectory following in the terms of the linear-quadratic problem. Presented in the paper exemplary simulation results demonstrate the effects of variations of the road surface, vehicle speed, and vehicle loading condition. The results show the complexity of the dynamic properties of the vehicle under study and confirm the benefits of the adopted solutions for vehicle automated control.

Gidlewski, Mirosław Jan, JANKOWSKI, Krystof, MUSZYŃSKI, Andrzej, ŻARDECKI, Dariusz

Arttest – a New Test Environment for Model-Based Software Development *CSP Meta QA Testing*

2017-01-00043/28/2017

Modern vehicles become increasingly software intensive. Software development therefore is critical to the success of the manufacturer to develop state of the art technology. Standards like ISO 26262 recommend requirement-based verification and test cases that are derived from requirements analysis. Agile development uses continuous integration tests which rely on test automation and evaluation. All these drove the development of a new model-based software verification environment. Various aspects had to be taken into account: the test case specification needs to be easily comprehensible and flexible in order to allow testing of different functional variants. The test environment should support different use cases like open-loop or closed-loop testing and has to provide corresponding evaluation methods for continuously changing as well as for discrete signals. In a joint project of RWTH Aachen University and Ford, a new tool, Arttest, has been developed for testing model-based software. The tool uses a domain specific language to specify the tests. It offers different test evaluation methods for automated open- and closed-loop testing and reactive testing. It automatically executes the tests, evaluates the outputs and generates summary reports indicating passed tests and errors found. The paper presents the tool and its various unique propositions such as domain specific test language, the evaluation properties and other features like open-loop and closed-loop capabilities.

Wiechowski, Norbert, Rambow, Thomas, Busch, Rainer, Kugler, Alexander, Hansen, Norman, Kowalewski, Stefan

Longitudinal Vehicle Dynamics Modeling and Parameter Estimation for Plug-in Hybrid Electric Vehicle

2017-01-15743/28/2017

System identification is an important aspect in model-based control design which is proven to be a cost-effective and time saving approach to improve the performance of hybrid electric vehicles (HEVs). This study focuses on modeling and parameter estimation of the longitudinal vehicle dynamics for Toyota Prius Plug-in Hybrid (PHEV) with power-split architecture. This model is needed to develop and evaluate various controllers, such as energy management system, adaptive cruise control, traction and driveline oscillation control. Particular emphasis is given to the driveline oscillations caused due to low damping present in PHEVs by incorporating flexibility in the half shaft and time lag in the tire model. Accurate and reliable vehicle dynamics parameters that control the vehicle motion are estimated by acquiring experimental data from longitudinal maneuvers of the PHEV equipped with a vehicle measurement system (VMS), global positioning system (GPS) and inertial measurement unit (IMU). The simulated model with estimated parameters is analyzed for longitudinal dynamics by comparing with experimental data from on-road testing.

Buggaveeti, Sindhura, Batra, Mohit, McPhee, John, Azad, Nasser

A Low Cost Rolling Road for Tire Measurements in a Small Eiffel Wind Tunnel

2017-01-15043/28/2017

Wind tunnel aerodynamic testing involving rolling road tire conditions can be expensive and complex to set up. Low cost rolling road testing can be implemented in a 0.3m2 Eiffel wind tunnel by modifying a horizontal belt sander to function as a moving road. This sander is equipped with steel supports to hold a steel plate against the bottom of the wind tunnel to stabilize the entire test section. These supports are bolted directly into the sander frame to ensure minimal vibrational losses or errors during testing. The wind tunnel design at the beginning of the project was encased in a wooden box which was removed to allow easier access to the test section for installation of the rolling road assembly. The tunnel was also modified to allow observers to view the testing process from various angles. These wind tunnel modifications include replacing the wooden panels with clear Lexan plastic sheets, adding dampening material into the test section connections, and making an easily interchangeable test piece in the side of the tunnel for quick experimental changes. The tire axle assembly, designed to hold the tire as it freely rotates on the sander belt, records the various forces acting on the wheel. The wind tunnel stinger uses a steel airfoil cross section with a ball joint pivot to transfer the forces and moments to load cells aligned with the desired force directions. The load cells are calibrated and forces measured using a LabVIEW computer system and force comparisons are made with a static tire under the same wind conditions to help determine differences between static tire testing and dynamic tire testing.

Tkacik, Peter, Carpenter, Zachary, Gholston, Aaron, Cobb, Benjamin James, Kennedy, Sam, Blankenship, Ethan, Uddin, Mesbah, Krishna Nukala, Surya Phani

Experimental Investigation of Aeroacoustic Cabin Noise in Unsteady Flow by Means of a New Turbulence Generating Device

2017-01-15453/28/2017

With advancement of aeroacoustic wind tunnels and CAE technology, aeroacoustic cabin noise in steady flow has been improved. On the other hand, passenger comfort is also impacted by aeroacoustic noise in unsteady flow. There have been comparatively few studies into this area, and the mechanism remains unclear. Considering the future proliferation of autonomous driving, drivers will pay more attention to cabin noise than previously, and aeroacoustic noise is expected to become more prominent. Thus, the reduction of fluctuating aeroacoustic noise is important. Most of the previous research relied on road tests, which don’t provide reproducible conditions due to changing atmospheric and traffic conditions. To solve these problems, research using devices that generate turbulence are being conducted. However, the fluctuations of flow generated in previous studies were small, failing to simulate on-road conditions sufficiently. In this report, the development of a new turbulence generating device for 1/1 scale wind tunnel is described. This device consists of dampers and airfoils at the nozzle, producing turbulence intensity up to 13%. Then the analysis of the fluctuating aeroacoustic noise generated using this device is presented. When the fluctuation frequency of the incoming flow is as high as 5Hz, aeroacoustic noise shows time delay and peak value declines in comparison to simulated cabin noise predicted by quasi-steady technique using the cabin noise and flow velocity measured in steady flow. It is also shown that the change of modulation of aeroacoustic noise due to the modification of vehicle shape could be evaluated quantitatively using this device.

Terakado, Susumu, Makihara, Takafumi, Sugiyama, Takashi, Maeda, Kazuhiro, Tadakuma, Kenji, Tsuboi, Kentaro, Iyota, Masashi, Kosaka, Kazuyoshi, Sugiyama, Sadato

Development of Ultra-Low Synergized PGM as Diesel Oxidation Catalyst for Heavy-Duty Applications

2016-01-232110/17/2016

Stricter regulatory standards are continuously adopted worldwide to control heavy duty emissions, and at the same time, fuel economy requirements have significantly lowered exhaust temperatures. The net result is a significant increase in Precious Group Metal (PGM) usage with current Diesel Oxidation Catalyst (DOC) technology. Therefore, the design and development of synergized precious metal (SPGM) in which ultra-low PGM is synergized with mixed metal oxide (MMO) to achieve highly beneficial emission performance improvement, is necessary. The presence of MMO in SPGM is responsible for NO oxidation to NO2 which is critical for the passive regeneration of the downstream filter and SCR function. This paper presents an initial study outlining the development of MMOs for application in modern DOCs and addresses some specific challenges underlying this application. Lab and flow reactor data in this study demonstrated SPGM DOCs thermal resistance and sulfur poisoning resistance. In addition, SPGM DOC with reduced PGM levels indicated the increase of NO2 production at T>250 °C compared to OEM benchmarks. This paper outlines the results of engine dyno, transient dyno and on-road testing of SPGM DOCs versus OEM DOCs. The engine testing indicated high level of NO2 production at significantly reduced PGM levels. On-road testing showed no change or deterioration of the system performance after the switch to SPGM for a heavy duty DOC and filter system. Field data logging during on-road testing showed identical exotherms for the same active regeneration calibration, which results in equivalent DPF regeneration. Disclosed SPGM for on-road heavy-duty applications is consistent with sufficient CO and HC conversion and superior warmed up NO2 make. Specific challenges remain in the development of the SPGM DOC which is under investigation based on formulation and mechanism of mixed metal oxides.

Nazarpoor, Zahra, Golden, Steve, Launois, Maxime, Kitazumi, Sen, Xie, Dianyong, McConnell, Campbell

A Simple Test Method to Monitor Emission Control Operating State Space (Emission Control Failure & Defeat Device Recognition)

2016-01-232410/17/2016

Modern light-duty vehicles require well-controlled engine-out feed-gas and very high catalyst efficiencies to meet the US Environmental Protection Agency (EPA) Tier 2 & 3 standards. When a vehicle with either a gasoline or diesel engine is operating within its controlled state-space the exhaust emissions present at the tailpipe are extremely low. When it is not operating within its controlled state-space the combustion process and therefore its exhaust emissions characteristics will be different. This may occur when an emission control device fails or if a defeat device is employed. Moreover, different control technologies each have unique characteristics or signatures that could assist in identifying either emission control device failure or an existing defeat device. A simple exhaust extension apparatus equipped with a thermocouple for measuring exhaust temperature and a NOx / O2 sensor to measure tailpipe NOx and O2 concentrations can characterize this signature information for pattern recognition analysis. This device can be used both in a laboratory environment with conventional batch sampling systems or for on-road testing as a compact emission measurement system. If this information was acquired during conventional laboratory emissions tests it would provide valuable dynamic system information. This information could characterize events such as cold start open loop operation, engine transient fuel compensation, and high-speed load enrichment and emission control device status with minimal cost.

Tang, Xiaoguo, McBryde, Dan

Functional Safety (ASIL-D) for an Electro Mechanical Brake

2016-01-19539/18/2016

Since more than eight years Vienna Engineering (VE) is working on an electro-mechanical brake (EMB) actuated by eccentrics and a highly non-linear actuation mechanism. The principle allows full braking in approx. 70 milliseconds (including air gap) and only approx. 3 A RMS actuator current at 12 V for classical ABS with oscillations. This EMB reached an elaborated state. Versions for passenger cars, elevators, railway and commercial vehicles (CVs) were derived. Now, as the EMB is going to road tests, it is necessary to fulfill safety requirements closely. What are these safety requirements and how can they be fulfilled? The properties of the overall system, of the mechanics and electronics of the single brake are discussed in this paper. The overall brake system for EMBs needs a truly redundant power supply, a safe control bus and a safe brake pedal. The mechanics of a single brake can be required to release when power is off and it must not get mechanically stuck. The electronics of each brake must fulfill safety integrity level ASIL-D, which can be interpreted as an extreme unlikeliness of a safety critical malfunction. It includes all electrically and electronically parts like connectors, actuator motor, its control, the microprocessor and all electronic components. The mechanical safety requirements were developed with a car manufacturer. The system architecture is an acknowledged bus and supply design. The ASIL-D brake electronics is currently implemented together with an electronics company that originated from safe aircraft electronics, e.g. gas turbine controllers (FADEC). The paper gives an overview of these topics, including details of the EMB control electronics, which is directly integrated into the brake. The simplicity of commanding EMBs and the very short actuation time makes certain EMBs ideal for autonomous driving and autonomous emergency braking.

Putz, Michael Herbert, Seifert, Harald, Zach, Maximilian, Peternel, Jure

Light, Desk, Aircraft

AS7768A (Historical)5/6/2016

This specification covers the requirements for a light assembly for use on aircraft cabin desks.

A-20C Interior Lighting

Design Optimization of An Integrated SCR System for EU V Heavy Duty Diesel Engines

2016-01-09454/5/2016

Selective Catalytic Reduction (SCR) based on urea water solution (UWS) has become a promising technology to reduce Nitrogen Oxides (NOx) emissions for mobile applications. However, urea may undergo incomplete evaporations, resulting in formation of solid deposits on the inner surfaces including walls and mixers, limiting the transformation of urea to ammonia and chemical reaction between NOx and ammonia. Numerous design parameters of SCR system affect the formation of urea deposits [1] ; they are: exhaust condition, injector type, injector mounting angle, geometrical configurations of mixer, injection rate and etc. Research has been available in urea deposits, mixers, urea injection rates and others [2,4,5,6]. In this paper, focus is placed on improving mixing structure design from baseline design of EU IV to EU V. On-road tests indicate that deposits are highly likely to occur near locations where spray and exhaust gas interact most. Analysis of test data shows that mixing structure influences the UWS distribution uniformity and the residence time, thus often becomes the main factor in causing deposit formation on the wall surface. To minimize urea deposit risks and improve the NH3 distribution uniformity, efforts have been taken to optimize the inlet and mixing configurations, the upstream baffle between the mixing chamber and catalyst chamber, and the injector seat of SCR system. Both Computational Fluid Dynamics (CFD) and tests are employed to identify areas of concern and to validate the improvement ideas. Distributions of Urea Water Solution (UWS), urea decomposition and droplet impingement on pipe wall are investigated. After new designs are proposed, engine bench emission tests, urea deposit tests, and on-road tests are used to validate the modified systems. It is found that the optimized design is able to improve ammonia distribution uniformity, eliminate urea deposits, improve NOx conversion efficiency, and satisfy the requirements of EU V emission regulations.

Zheng, Guanyu, Zhang, Suying, Wang, Fengshuang, Liu, Zhengrui, Tao, Jianzhong

Process Automation to Generate Road Drive Files in Laboratory Testing Using Virtual Iterations Method

2016-01-13594/5/2016

At present, vehicle testing in laboratory is one of the important phase to quicken the product validation process. In the early phase of laboratory testing it is required to evaluate the strength of the vehicle structure through physical rig setup which represents the consumer’s usage. Two and Multiple poster input excitation are among the laboratory rig testing to represent the actual road are used to predict the durability of vehicle components. The road inputs through the poster are known as drive files, a feedback controlled system which reproduces the track or real road recorded specimen’s accelerations, displacements and strains in laboratory. Derivation of drive files in poster testing requires iteration of physical specimen to exactly replicate the actual road. This paper discusses about generation of drive files as inputs for poster actuation with virtual model(as a substitute for actual model)which is applicable in areas of vehicle durability and ride comfort studies. For the reason to minimize the time,cost,man-machine hours and energy, an automation is developed to simulate the validated virtual model with iterations process to generate the road files for further use in physical and virtual test.The paper details on the procedure followed traditionally and what changes have been made in the current process to generate road drive input files.

Pradeepak, R., Kumbhar, Shyamsundar, Barhate, Nainishkumar

Optimization of Suspension System of Self-Dumping Truck Using TOPSIS-based Taguchi Method Coupled with Entropy Measurement

2016-01-13854/5/2016

This study presents a hybrid optimization approach of TOPSIS-based Taguchi method and entropy measurement for the determination of the optimal suspension parameters to achieve an enhanced compromise among ride comfort, road friendliness which means the extent of damage exerted on the road by the vehicles, and handling stabilities of a self-dumping truck. Firstly, the full multi-body dynamic vehicle model is developed using software ADAMS/Car and the vehicle model is then validated through ride comfort road tests. The performance criterion for ride comfort evaluation is identified as root mean square (RMS) value of frequency weighted acceleration of cab floor, while the road damage coefficient is used for the evaluation of the road-friendliness of a whole vehicle. The lateral acceleration and roll angle of cab were defined as evaluation indices for handling stability performance. The spring stiffness and shock absorber damping of the front suspension, spring stiffness of the rear suspension, torsional stiffness of the front and rear anti-roll bar are taken as the design variables, which are considered at three levels. A L18 orthogonal array is applied to implement the simulations, and the TOPSIS is thus used to integrate all determined performance criteria of ride comfort, road friendliness and handling stability into a single performance index. Meanwhile, the weights of the quality characteristics are determined by employing the entropy measurement method. Furthermore, the best factor levels are identified according to the Taguchi method principles for single response optimization. Finally, the optimal combination of suspension parameters is confirmed to illustrate the effectiveness of the proposed hybrid optimization method.

Jiang, Rongchao, Wang, Dengfeng

Determination of Critical Speed, Slip Angle and Longitudinal Wheel Slip based on Yaw Marks Left by a Wheel with Zero Tire Pressure

2016-01-14804/5/2016

This article presents the results of an analysis of the yaw marks left by a car with normal pressure in all tires and then normal pressure in three tires and zero in one rear tire. The analysis is a continuation of research on influence of reduced tire pressure on car lateral dynamics in a passing maneuver, discussed in the SAE paper No. 2014-01-0466. Preliminary analysis of yaw marks has shown, that a wheel with zero pressure deposits a yaw mark whose geometry differs from the yaw mark made by a wheel with normal pressure based on which we could calculate: critical speed, slip angle and longitudinal wheel slip. The aim of the presented research was to analyze the yaw marks left by car with zero pressure in one rear wheel in order to check the possibility of determining the vehicle critical speed, slip angle and longitudinal wheel slip. It was reached by performing bench and road tests during which the vehicle motion parameters were recorded using GPS Data Logging System. The results of calculations based on the geometric characteristics of yaw marks were compared with real values obtained from the measurements of vehicle motion parameters.

Zebala, Jakub, Wach, Wojciech, Ciępka, Piotr, Janczur, Robert

An Innovative Control Algorithm for Engine Stop/Start for Vehicles with Manual Transmission, Derived through Analysis of On-Road Test Data

2016-01-06234/5/2016

Micro and Mild Hybrid Systems is a bracket term, which covers functions like Engine Stop/Start (ESS), Intelligent Alternator Control (IAC), and many others, which collectively aim at optimizing the fuel consumption by preventing the wasteful running of the engine. Engine Stop/Start system is the prominent part of the Micro/Mild hybrid systems and is the most significant contributor while reducing the fuel consumption and greenhouse gas emissions. In the previous work of the Authors, various issues related to ESS were discussed in detail. ESS is not so popular among the customers, due to the complexities of the system operation and poor integration of the system design with the customer behavior. In addition, due to various functional safety conditions, and the traffic conditions, the actual benefits of ESS are negatively impacted. Therefore, it becomes necessary to have a different approach to the design of the systems like ESS. A different approach was implemented to design the control algorithm for the ESS, by implementing Design Thinking, in which a detailed study was performed to assess how customers actually behave during an idle stop and inputs were generated for the control algorithm design. This effort resulted in a better system design with increased improvement of fuel efficiency and better integration of the system functionality with the user behavior. In this paper, the technical aspects of the system design are discussed in detail, with analysis of the on road data of customer behavior, analysis of the problem areas, and methods devised to improve the integration of the system functionality with the customer behavior, customer experience with the ESS, and to reduce the negative impact of the functional safety parameters, including the implementation of the system in a technology demonstrator vehicle and its performance test results. The vehicle with the new control algorithm returned a fuel economy improvement of approximately 18% over conventional vehicle, and 13% compared to the base ESS control algorithm, under actual on-road conditions.

Athani, Gopal, Dongare, Kapil, Gavarraju, Srinivasa

Application of PHEV Fractional Utility Factor Weighting to EcoCAR On-Road Emissions and Energy Consumption Testing

2016-01-11804/5/2016

EcoCAR is North America's premier collegiate automotive engineering competition, challenging students with systems-level advanced powertrain design and integration. The EcoCAR Advanced Vehicle Technology Competition series is organized by Argonne National Laboratory, headline sponsored by the U.S. Department of Energy and General Motors, and sponsored by more than 30 industry and government leaders. In the last competition series, EcoCAR 2, fifteen university teams from across North America were challenged to reduce the environmental impact of a 2013 Chevrolet Malibu by redesigning the vehicle powertrain without compromising performance, safety, or consumer acceptability. This paper examines the results of the EcoCAR 2 competition’s emissions and energy consumption (E&EC) on-road test results for several prototype plug-in hybrid electric vehicles (PHEVs). The official results for each vehicle are presented along with brief descriptions of the hybrid architectures. In addition to the official competition results, this paper investigates two methods used to utility factor (UF) weight E&EC test data. This investigation was conducted to select a methodology for calculating E&EC results in the EcoCAR 3 competition, where teams will reduce the environmental impact of a 2016 Chevrolet Camaro. The paper uses the EcoCAR 2 Year 3 data to quantify the impacts of using both a fractional UF-weighting method and applying a single vehicle UF on E&EC results for electric and fuel energy consumption. In the discussion it is shown that both UF-weighting methods produced similar results for fuel and electric energy consumption for a representative test vehicle. UF-weighting of criteria emissions is also investigated.

Crain, Trevor, Gorgia, Thomas, Alley, R. Jesse

Aerodynamic Drag Reduction of a Light Truck - from Conceptual Design to Full Scale Road Tests

2016-01-15944/5/2016

Considerable amounts of the everyday goods transports are done using light trucks. In the last ten years (2005-2015), the number of light trucks has increased by 33 % in Sweden. The majority of these light trucks are fitted with a swap body and encounter the same problem as many other truck configurations, namely that several different manufacturers contribute to the final shape of the vehicle. Due to this, the aerodynamics of the final vehicle is often not fully considered. Hence there appears to be room for improving the aerodynamic performance. In this study the flow around a swap body fitted to a light truck has been investigated using Computational Fluid Dynamics. The focus has been on improving the shape of the swap body in order to reduce both the aerodynamic drag and fuel consumption, while still keeping it usable for daily operations. Reynolds-Averaged Navier-Stokes simulations were used for concept evaluation while more advanced Detached Eddy Simulations were performed on the best concept in order to investigate details of the flow. Various concepts were evaluated from which it could be seen that a more streamlined top of the swap body together with a lowered top trailing edge had a significant positive effect on the aerodynamic drag. A full scale light truck was equipped with a swap body with with these modifications for road tests. During a test period, a mean fuel consumption reduction of 12 % was measured, thus indicating a significantly reduced aerodynamic drag.

Ekman, Petter, Gardhagen, Roland, Virdung, Torbjorn, Karlsson, Matts

Analysis Lead Drivability Assessment

2015-01-28049/29/2015

Drivability and powertrain refinement continue to gain importance in the assessment of overall vehicle quality. This notion has transcended its light duty origins and is beginning to gain considerable traction in the medium and heavy duty markets. However, with drivability assessment and refinement also comes the high costs associated with vehicle testing, including items such as test facilities, prototype component evaluation, fuel and human resources. Taking all of this into account, any and all measures must be used to reduce the cost of drivability evaluation and powertrain refinement. This paper describes an analysis based co-simulation methodology, where sophisticated powertrain simulation and objective drivability evaluation tools can be used to predict vehicle drivability. A fast running GT power engine model combined with simplified controls representation in Matlab/Simulink was used to predict engine transients and responses. This high fidelity engine model was coupled with a detailed vehicle model in an AVL CRUISE™ environment that included dynamic models of the various driveline elements. With such a detailed vehicle model, specific driving scenarios and conditions were simulated and the responses were passed to AVL DRIVE™ for drivability evaluation. AVL DRIVE is a drivability evaluation tool comprising of a data collection system and data analysis software that can recognize and score individual drivability events. Within Drive the collected objective data was compared to a database of best in class vehicles and a subjective driveability score based on a 1-10 scale was returned. The results of this initial drivability simulation were then used to determine needed improvements to the powertrain calibration and control strategy. While this study is a preliminary step towards using analytical models for driveability assessment, greater refinement of the models is necessary in order to achieve better correlation with the experimental data. Such a methodology can tremendously reduce the amount of time and effort required to understand and tune drivability, before on-road testing commences.

Walters, Travis Lee, Shaw, Phillip, Madurai Kumar, Mahesh, Hoop, Joshua

Standard Formats for Presenting Acoustical Data

J2629_201508 (Current)8/11/2015

SAE developed this document and associated spreadsheets at the request of automobile manufacturers to help compare products from multiple suppliers using standard data presentation formats. This document includes several preferred formats for presenting acoustical data on materials, components, systems, or vehicles. These formats cover the range of acoustical tests commonly conducted in the automotive industry. These tests follow SAE and ASTM test practices as well as vehicle specific test methods. For each test, the details of samples and test conditions can be entered into an applicable electronic spreadsheet together with the acoustical results data. These data are then linked to standard graphical display(s) for each test. All manufacturers and suppliers in this industry are encouraged to present data and results in these formats. Although this practice was developed specifically for use in the automotive industry, the formats may be usable in other industries and applications as well.

Acoustical Materials Committee

Durability Analysis of Motorcycle Front Fender through Virtual Simulation, on Road Testing and Laboratory Testing Using NVH Tool

2015-01-22646/15/2015

In India, demand for motorcycle with good comfort is increasing among the customers thereby the vibration reduction of two wheelers is key parameter for motorcycle manufacturers. In order to overcome the demand in the market, manufacturers are giving more importance to cost of the product by reducing the material. This results in the reduction of the life cycle of the vehicle models and drives the manufacturers to different product design philosophies and design tools, as one would expect. One of the performance factors that continue to challenge designers is that of vehicle vertical acceleration experienced by the motorcycle components. An essential tool in the motorcycle development process is the ability to quantify the durability of the component. This paper main objective is to increase the life of the motorcycle front fender through virtual simulation, on road testing and laboratory testing using NVH tool. Vibration and strain level on the front fender was measured on torture track. Accelerometers are mounted on the vehicle to extract the dynamic accelerations on the motorcycle at various connections points like front and rear axle, front steering pivot, rear cushion top pivot fender and rider foot rest during the process. On the other hand, a similar condition is simulated by using simulation using MSC.ADAMS. Finally, a qualitative comparison is made between the results of simulations and experiments. Then conversion of track time domain data into NVH data and then performing laboratory testing to find out the life of the component. The results show that both natural frequencies of the transfer path are observed same in the experiments as well as simulations.

Subbu, Rama, Anthonysamy, Baskar, Sharma, Piyush Mani

Evaluating Vibrational Behavior of Coupled Dynamic Systems in Engine Test Cells

2015-01-23466/15/2015

From a facility perspective, engine test cells are rarely evaluated for their vibration levels in their functional configuration. When complicated dynamic systems such as an internal combustion engine and a dynamometer are coupled together using driveshafts and coupling components, the overall system behavior is significantly different from that of the individual sub-systems. This paper details an instance where system level experimental testing and finite element analysis methods were used to mitigate high vibration levels in an engine test cell. Modal and operational test data were taken to establish baseline vibration levels at a diesel engine test cell during commissioning. Measurements were taken on all major sub-systems such as the engine assembly, dynamometer assembly, intermediate driveshaft bearing pedestal and driveshaft components. Correlation of modal data with order tracked data derived from operational testing revealed an axial mode of the driveshaft bearing pedestal that was getting excited by a higher order vibration of the dynamometer trunnion bearings. Continued operation in this condition would have led to structural failure of the dynamometer bearings and significant wear of the intermediate driveshaft bearings. The sensitivity of the driveshaft bearing mode was quantified using temporary structural changes in the field and subsequent testing. When these changes showed promising results, finite element analysis methods were used to develop a more permanent design solution to achieve vibration mitigation. This led to a revised support structure for mounting the driveshaft bearing on its base pedestal. The final design was installed in the test cell and its performance was validated by repeating the modal and operational tests. This case aims to emphasize the need for more system level testing in coupled dynamic systems that will eventually enable avoiding damage to test equipment and downtime in engine test facilities.

Swaminathan, Balakumar

Design and Dynamic Analysis of Bounce and Pitch Plane Hydraulically Interconnected Suspension for Mining Vehicle to Improve Ride Comfort and Pitching Stiffness

2015-01-06174/14/2015

This paper demonstrates time response analysis of the mining vehicle with bounce and pitch plane hydraulically interconnected suspension (HIS) system. Since the mining vehicles working in harsh conditions inducing obvious pitch motion and the hard stiffness of suspensions leading to the acute vibration, the passive hydraulically interconnected system is proposed to provide better ride comfort. Furthermore, the hydraulic system also increases the suspension stiffness in the pitch mode to prevent vehicle from large pitch motions. According to the hydraulic and mechanical coupled characteristic of the mining vehicles, a 7degrees of freedom (7-DOFS) mathematical model is employed and the state space method is used to establish the mechanical and hydraulic coupled dynamic equations. In this paper, the vehicles are subjected to straight line braking input, triangle block bump input applied to the wheels and random road tests. By discussing the result of the simulation, the HIS system can provide a reasonable comfort performance. From the angle of time domain, the analysis of mining vehicle dynamic response characteristics is obtained; the result shows that the hydraulically interconnected system can reduce the vertical stiffness and add the pitch stiffness in order to improve the ride comfort and reduce the pitch motion.

Zhang, Jie, Chen, Xiao, Zhang, Bangji, Wang, Lifu, Chen, Shengzhao, Zhang, Nong

Aerodynamic Drag Reduction - from Conceptual Design on a Simplified Generic Model to Full-Scale Road Tests

2015-01-15434/14/2015

Road transportation by trucks is the major part of the goods transportations system in the European Union (EU), and there is a need for increased fuel efficiency. While truck manufacturers already spend significant resources in order to reduce the emissions from their vehicles, most truck manufacturers do not control the shape of the trailer and/or swap bodies. These devices are usually manufactured by different companies that cannot consider the overall aerodynamics around the complete vehicle. By use of Computational Fluid Dynamics (CFD) and previous wind tunnel experiments, the flow around a simplified generic tractor-trailer model has been investigated. With better understanding of the flow features around the tractor with attached trailer or swap bodies, an improved design of the trailer and swap body can be achieved, which is the aim for the project. Special emphasis is put on achieving simple, easy to install or implement drag-reducing geometrical modifications to the trailer or swap bodies that can be mounted on existing trucks. Reynolds-Averaged Navier-Stokes (RANS) simulations were used for the conceptual development phase where trends in drag reduction due to the modified geometries were studied using a parameter study, while more advanced scale resolving simulations (SRS) were used in order to investigate the details of the flow fields. The investigation indicates that aerodynamic drag reduction is possible with quite simple geometrical modifications. Some of the results have also been verified through road tests of vehicles in commercial use, which has shown reduced fuel consumption of up to 5%.

Ekman, Petter, Gårdhagen, Roland, Virdung, Torbjörn, Karlsson, Matts

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