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Technical Paper

An Innovative Test System for Holistic Vehicle Dynamics Testing

2019-04-02
2019-01-0449
In the automotive industry, there is a continued need to improve the development process and handle the increasing complexity of the overall vehicle system. One major step in this process is a comprehensive and complementary approach to both simulation and testing. Knowledge of the overall dynamic vehicle behavior is becoming increasingly important for the development of new control concepts such as integrated vehicle dynamics control aiming to improve handling quality and ride comfort. However, with current well-established test systems, only separated and isolated aspects of vehicle dynamics can be evaluated. To address these challenges and further merge the link between simulation and testing, the Institute of Internal Combustion Engines and Automotive Engineering (IVK), University of Stuttgart is introducing a new Handling Roadway (HRW) Test System in cooperation with The Research Institute of Automotive Engineering and Vehicle Engines Stuttgart (FKFS) and MTS Systems Corporation.
Technical Paper

Design of Super Silent Enclosure for Diesel Genset Using Statistical Energy Analysis (SEA) Technique

2019-01-09
2019-26-0185
Diesel engine generators are commonly used as a power source for various industrial and residential applications. While designing diesel generator (DG) enclosures requirements of noise control, ventilation and physical protection needs to be addressed. Indian legislation requirement demands DG enclosure insertion loss (IL) to be minimum 25 dB. However for certain critical applications like hospitals, residential apartments customer demands quiet DG sets than the statutory limits. IL targets for such application ranges between 35-40 dB. The objective of this paper is to develop methodology to design ‘Super Silent’ enclosure with IL of 35 dB by Statistical Energy Analysis (SEA) approach for small capacity DG set. Major challenge was to achieve IL of 35 dB with single enclosure and making use of SEA technique for small size enclosure wherein modal densities is very less. Major airborne noise sources like engine, radiator fan and exhaust were modelled by capturing noise source test data.
Technical Paper

BIOT’s Parameters Evaluation and Prediction of Flat and Molded Dash Panel Acoustic Performance and It’s Validation

2019-01-09
2019-26-0195
In today’s automotive industry sound package material design and optimization is important considering the need for weight reduction and achieving targeted sound absorption and sound transmission loss values. As per traditional approach vehicle level noise reduction targets are defined considering flat samples, but in actual vehicle condition molded trimmed parts are used. This paper discusses about the systematic methodology developed for molded sample characterization in terms of BIOT’s properties. Effects of different parameters like area wise thickness variation, density variation on BIOT properties is studied. Comparison of BIOT’s properties of flat and molded dash sample is done to study the effect of molded structure. Using these BIOT’s properties prediction of sound absorption and sound transmission loss results carried out using FTMM approach for flat sample and SEA approach for molded sample.
Technical Paper

Dynamic Response Evaluation of a Chassis of a Generator Set Using FEA techniques

2019-01-09
2019-26-0198
A Generator set is comprised of mainly an Engine, Alternator and Chassis. High Horse-Power Generator development is challenging, with lots of complexities in physical and virtual validations. Creating high fidelity analytical model is always beneficial and economical at the design stages as it avoids repetitive tests on various design concepts. This paper reports analytical methods of developing an FEA model of a Generator for locomotive application and its correlation with Test. Highlighted as well are some of the challenges faced in FE modeling of a large Generator model (60 liters engine capacity) with node count of around 4 million. In this technique, Modal Analysis is first performed to capture the dynamic behavior. More than 95 % correlation is achieved between the FEA and test natural frequencies (Bending modes). Harmonic Analysis with Modal Superposition is then applied to understand the dynamic response of a Chassis under the action of engine vibratory loads.
Technical Paper

Heat-Treatment Process Optimization Using Dilatometry Technique and Simulation Tools

2019-01-09
2019-26-0242
Any metal component undergoes various treatments to get desired shape and desired properties. Some of the important properties are strength, hardness, % elongation etc. which comes under mechanical properties. These properties can be easily achieved through heat-treatment process. Typical example of heat-treatment processes are hardening and tempering in case of steel and aging process in case of aluminium alloys. Some of the new emerging materials viz. micro alloy steel does not require any hardening and tempering if cooling rate is maintained. Heat-treatment cycle depends on material grade and its alloying elements. A heat-treatment cycle for any grade is generally fixed based on conventional methods but they are not optimized. The need of hour is to optimize the heat-treatment cycle to improve productivity and energy consumption. Dilatometer is used to optimize heat-treatment cycle on sample level whereas simulation tools can be used for component level.
Technical Paper

Chemical Kinetics Modelling of Exhaust After-Treatment System: A One Dimensional Simulation Approach

2019-01-09
2019-26-0249
The Indian automotive industry has taken a big leap towards stringent Bharat Stage VI (BS VI) emission standards by year 2020. A digital driven design and development focusing on innovative and commercially viable technologies for combustion and exhaust after-treatment system is the need of the time. One-dimensional (1D) simulation serves as a best alternative to its counterparts in terms of obtaining faster and accurate results, which makes it an ideal tool for carrying out optimization studies at system level. In this work, 1D chemical kinetics modelling and analysis of exhaust after-treatment system (EAT) for a heavy-duty diesel has been performed using GT-Power. Initially, a single site 1D model for a diesel oxidation catalyst (DOC) has been developed and then, a two-site, 1D model for a selective catalytic reduction (SCR) catalyst was also developed based on reactor data.
Technical Paper

Improving Calibration Quality by Virtual Testing Approach for BS VI Emission Norms

2019-01-09
2019-26-0252
BS-VI or equivalent development calls for tremendous efforts in concept investigation and calibration for engine out, after treatment, diagnostic checks, off-cycle emissions, field performance, component safety etc. Achieving calibration quality for all these tasks is very challenging considering development time and cost with conventional physical testing approach. Present article focuses on assessment of testing and calibration using virtual approach. To prove and validate this approach, a six-cylinder heavy duty diesel engine is selected and configured in HiL environment. The engine plant model is built offline and validated with base engine data at steady state and transient operations and RT model is integrated with ECU hardware. Data for plant model corrections is generated with short measurement campaign. Refined real time plant model is prepared for evaluating different calibration strategies on virtual test bed environment.
Technical Paper

Case Study on Thermal Management Strategies for HDD BS VI Exhaust Aftertreatment Performance Using Semi Physical Modelling Approach

2019-01-09
2019-26-0270
This paper focuses on assessment of different thermal management strategies for heavy duty Diesel(HDD) engine aftertreatment using semi-physical model for both engine and aftertreatment. Aftertreatment configuration of DOC, DPF and SCR is considered for six cylinder HDD engine. SCR reaction kinetics, ammonia adsorption and desorption parameters were calibrated with the data from synthetic test bench. Calibrated aftertreatment model is integrated with semi physical 6-cylinder HDD engine model to validate over steady state as well as transient measurement data. Engine model is modified for different thermal management strategies such as Intake, Exhaust throttle valve, start of main injection, Post injection and evaluated for their impact on performance and emission parameters. Results over operating point are analysed to select best strategy at cold operating zone.
Technical Paper

Methodology Development for External Aerodynamic Evaluation of a Bus and Its Impact on Fuel Economy along with Experimental Validation

2019-01-09
2019-26-0294
The objective of this study is to develop, demonstrate and validate the methodology of external aerodynamic analysis of a State Road Transport bus for prediction of drag coefficient and its impact on fuel consumption with experimental validation. It has been verified that vehicle consumes around 40% of the available engine power to overcome the air drag. This gives us a huge scope to study the effect of aerodynamic drag. Baseline model of State Road Transport Bus was evaluated for estimating fuel consumption using Computational Fluid dynamics (CFD) methodology. The CFD results were validated with the experimental data with less than 10% deviation. Bus design was optimized with an objective of reducing the fuel consumption with parameters like angle of windshield, rounding and tapering corners and rear draft angle. Optimized bus design is also ensured to meet functional specifications as per AIS052.
Technical Paper

LEAN Techniques for Effective, Efficient and Secure Information Processing in Automotive Homologation

2019-01-09
2019-26-0335
It is an established fact that virtual knowledge based engineering has revolutionized R & D activities by streamlining processes, ensuring productivity and accuracy. This has resulted in freeing up time for quality interpretational work and decision making for engineering the best of products. Subsequently, homologation is a mandatory requisite activity for product signoff. It certifies the quality of the product and is an important factor in giving the product an authenticity for sale in the market. Homologation entails compliance to regulations existing in form of well-established standards which elaborate systematic and detailed guidelines on conducting physical testing for automotive systems, sub-systems or components for specific vehicle types.
Technical Paper

Numerical and Experimental Analysis of Intake Flow Structure and Swirl Optimization Strategies in Four-Valve Off-Highway Diesel Engine

2019-01-09
2019-26-0042
Future emission limits for off-highway application engines need advanced power train solutions to meet stringent emissions legislation, whilst meeting customer requirements and minimizing engineering costs. DI diesel engines with four valves per cylinder are widely used in off- highway applications because of the fundamental advantages of higher volumetric efficiency, lower pumping loss, symmetric fuel spray & distribution in combination with the symmetric air motion which can give nearly optimal mixture formation and combustion process. As a result, the fuel consumption, smoke levels and exhaust emissions can be considerably reduced. In particular, the four-valve technology, coupled with mechanical low pressure and electronic high pressure fuel delivery systems set different requirements for inlet port performance. In the present paper four valve intake port design strategies are analysed for off highway engine using mechanical fuel injection systems.
Technical Paper

Development of a Parametric Model for Burn Rate Estimation in Direct Injection Diesel Engine

2019-01-09
2019-26-0035
In internal combustion engines, rate of fuel burning known as burn rate is a simplified representation of complex in-cylinder combustion process. It is considered as a prime input especially in 1D simulation tool for all important thermodynamic studies. A novel parametric model for prediction of burn rate in heavy duty Direct Injection (DI) diesel engine has been introduced in the present work. A wide range of experimental data with more focus on higher load points with different in-cylinder combustion characteristics is considered and burn rates have been generated using measured pressure trace. Generated burn rates have been studied over different phases of combustion. These burn rate shapes have been analyzed to understand the effect of fuel injection system, air management subsystem parameters along with in-cylinder conditions on combustion. Different mathematical modelling approaches for burn rate approximation like Wiebe function have been studied.
Technical Paper

Modeling and Simulation of Steady State Handling Characteristics of Formula Vehicle with Antiroll Bars

2019-01-09
2019-26-0068
Antiroll bar plays an important role in rollover stability of the vehicle. But not only does it limit the vehicle roll during cornering, but also alters the lateral load transfer between the tracks, which in turn affects the cornering performance of the vehicle. This paper deals with the design and mathematical modeling of antiroll bars to reduce the body roll of the vehicle from 1.5°/g to less than 1.0°/g. Rear bar uses a conventional torsion type bar but the front anti roll mechanism is an unconventional antiroll bar using a rotating double cantilever mechanism. Mathematical modeling is done for pushrod rod actuated antiroll mechanisms to simulate its non-linear roll rates. Antiroll bars for front and rear are designed for the calculated stiffness. Finite Element Analysis of antiroll bar and its components is done and the mechanism is tested on the vehicle. Steady state tire model parameters are generated by curve fitting tire testing data into pacejka coefficients.
Technical Paper

Development of Autonomous Vehicle Controller

2019-01-09
2019-26-0098
Autonomous driving is looked upon as solution for future of automotive vehicles. The technology has tremendous possibilities to improve safety, fuel economy, comfort, cost of ownership etc. The project to develop an autonomous controller from scratch was undertaken, with objective to drive under selected test scenarios. The car, modified to drive using this autonomous controller, is able to handle these scenarios. The key scenarios include ability to successfully drive on tracks with well-marked lanes, Follow the route as per selected trip plan file, recognize and follow all traffic road signs, traffic signals en-route, identify other vehicles on the road or pedestrians in the lane and take the appropriate action. The development was carried out using frugal engineering approach. As the Autonomous Vehicle technology is still under development, the standard proven published approaches are not available.
Technical Paper

Component Tests Based on Vehicle Modeling and Virtual Testing

2017-03-28
2017-01-0384
ADAMS, SIMULINK, and ADAMS-SIMULINK co-simulation models of component test systems, Multi-Axis-Simulation-Table (MAST) systems, and spindle-coupled vehicle testing system (MTS 329) were created. In the ADAMS models, the mechanical parts, joints, and bushings were modeled. Hydraulic and control elements were absent. The SIMULINK models modeled control and hydraulic elements including actuator dynamics, servo valve dynamics, closed loop control, three-variable control, matrix control, and coordinate transformation. However, the specimen had to be simplified due to the limitation of SIMULINK software. The ADAMS-SIMULINK co-simulation models considered hydraulic and control components in the SIMULINK portion and mechanical components in ADAMS portion. The interaction between the ADAMS and SIMULINK portions was achieved using ADAMS/Control.
Technical Paper

Influence of Rake Angle and Cutting Speed on Residual Stresses Developed in Cutting Tool during Turning Operation

2014-04-28
2014-28-0014
In this work, the effect of tool rake angle and cutting speed on residual stresses of tool was studied, the rake angles of 0°, 5°, 10°, 15°, and 20° and a constant clearance (Relief angle) of 8° were used to turn bright mild steel on the lathe machine, A total of 15 experiments were carried out with three different cutting speeds (37.69, 59.37, 94.24 m/min) for each rake angle, keeping the feed rate and depth of cut constant. During the experimentation, the residual stresses were measured using an x-ray diffractiometer. This is all in order to explore the energy savings opportunities during regrinding of tools, useful production time and energy is being wasted due to regrinding or re-sharpening of tools when cutting tools got worn or blunt, selection of the rake angle which generate the optimum residual stresses in the tool, goes a long way in saving these time and energy.
Technical Paper

Optimization in Forging Process Using Computer Simulation

2014-04-28
2014-28-0041
New process development of forging component require lot of process knowledge and experience. Even lots of trial-and-error methods need to be used to arrive at optimum process and initial billet dimensions. But with help of reliable computer simulation tools, now it is possible to optimize the complete process and billet dimensions without a single forging trial. This saves lot of time, energy and money. Additionally, simulation gives much more insight about the process and possible forging defects. In this paper, a complete forging process was needed to be designed for a complex component. With the help of computer simulation, the complete conventional forging process and modified forging process were simulated and optimized. Forging defects were removed during optimization of the process. Also billet weight optimization was carried out. Deciding the pre-forming shape of the billet was the main challenge.
Journal Article

Development of a Full-Vehicle Hybrid-Simulation Test using Hybrid System Response Convergence (HSRC)

2012-04-16
2012-01-0763
Hybrid vehicle simulation methods combine physical test articles (vehicles, suspensions, etc.) with complementary virtual vehicle components and virtual road and driver inputs to simulate the actual vehicle operating environment. Using appropriate components, hybrid simulation offers the possibility to develop more accurate physical tests earlier, and at lower cost, than possible with conventional test methods. MTS Systems has developed Hybrid System Response Convergence (HSRC), a hybrid simulation method that can utilize existing durability test systems and detailed non-real-time virtual component models to create an accurate full-vehicle simulation test without requiring road load data acquisition. MTS Systems and Audi AG have recently completed a joint evaluation project for the HSRC hybrid simulation method using an MTS 329 road simulator at the Audi facility in Ingolstadt, Germany.
Video

Advances of Virtual Testing and Hybrid Simulation in Automotive Performance and Durability Evaluation

2012-02-15
Virtual testing is a method that simulates lab testing using multi-body dynamic analysis software. The main advantages of this approach include that the design can be evaluated before a prototype is available and virtual testing results can be easily validated by subsequent physical testing. The disadvantage is that accurate specimen models are sometimes hard to obtain since nonlinear components such as tires, bushings, dampers, and engine mounts are hard to model. Therefore, virtual testing accuracy varies significantly. The typical virtual rigs include tire and spindle coupled test rigs for full vehicle tests and multi axis shaker tables for component tests. Hybrid simulation combines physical and virtual components, inputs and constraints to create a composite simulation system. Hybrid simulation enables the hard to model components to be tested in the lab.
Technical Paper

Design of High Speed Engine's Cam Profile Using B-Spline Functions for Controlled Dynamics

2012-01-09
2012-28-0006
Recent trends towards design of High Performance Diesel engines creating more challenges in the area of design, durability and NVH aspects of components and systems. In particular, Valvetrain system of High Speed application engines is one of the most critical and complicated dynamic system in terms of precise control of events, max. Lift, control over accelerations and vibration related issues. This can be tackled by designing the cam profile for better valve train dynamics. High frequency components and/or excessive jerks in a cam profile are important sources of cam-follower vibrations. There are various techniques of designing cam profile to achieve controlled valve train dynamic behavior at high speed operations. Present paper discuss the impact of various cam profile options designed using Polydyne, N-Harmonic and B-Spline methodologies on a field problem of cam wear for high speed engine application.
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