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Technical Paper

Reducing Brake Steer Which Causes Vehicle Drift During Braking

2019-01-19
2019-26-0072
Brake steer is an undesirable phenomenon where a vehicle deviates to one side of the road during braking. Vehicle deviation i.e. drift causes driver discomfort, where a driver has to constantly apply Steering Wheel corrections while braking in order to safely maintain the desired path. In a particular segment of commercial vehicle, an issue of unacceptable right-side vehicle drift during braking was observed which was making the drive of the vehicle unsafe for the driver. Aim of this paper is to analyse the probable causes of such a vehicle drift, to objectively measure actual brake steer and corresponding vehicle drift during braking using a unique methodology. In this paper, the root cause of the brake steer is discussed and an improvement on the vehicle is proposed by changing kinematic points of suspension and steering linkage to reduce the brake steer to the limit that vehicle drift is almost eliminated and vehicle becomes completely safe for the driver to drive.
Technical Paper

Modifications in Mini-Bus Design for Drag Reduction

2019-01-19
2019-26-0071
The purpose of this study was to develop the aerodynamic study of a minibus vehicle. With the objective of reducing Power consumption, as Mini-Bus is designed as H2-O2 fuel cell and electric Bus and consequently no emissions are created to the environment. The proposed initial of the project was to identify the aerodynamic coefficient of the existing vehicle from the 3D CAD model. After preliminary analysis of the model and based on studies conducted are effected changes in order to achieve better results in the design of new generations of the vehicle. The simulation of the air flow over the vehicle was performed in three steps: design on Catia, discretization of the computational domain using Computational Fluid Dynamics (CFD) meshing and ANSYS (FLUENT) solve to CFD. We used the turbulence models of two equations k-ε Standard and k-ε Realizable having a better approximation of the actual result.
Technical Paper

Evaluation of Slow Speed Off-Tracking of Steerable Axle Tractor Trailer Combinations

2019-01-19
2019-26-0069
Steerable multi axle trailers are deployed for transportation due to their cost effectiveness and improved manoeuvrability then non-steered trailers. High speed manoeuvres of steerable axle trailer are considered dangerous for stability due to complex dynamic behaviour and researched for decades. Off-Tracking is an important parameter which influences the dynamic behaviour of steerable axle trailer at both low and high speed. Off-tracking is defined as maximum radial offset between path of the tractor’s front axle centre and trailer’s rearmost axle centre during a specific manoeuvre. Off-tracking, being a slow speed phenomenon becomes major concern for safe and accident free movement even at slow speeds. A linear 3-DOF yaw plane model of steerable axle tractor trailer combination is developed using Lagrangian approach, which requires steering angles of truck’s front axle and all trailer axles to simulate the system.
Technical Paper

Safety and Comfort for All: An Affordable Hill-Hold and Automated Parking Brake System

2019-01-19
2019-26-0005
With an ever increasing number of vehicles on Indian roads, the safety and ease of driving has become a very important criterion for the customers. In passenger and commercial vehicles, while launching a vehicle on gradient or stop and go traffic in hilly region, the vehicle tends to roll back due to the slope. This is also a safety issue, as this may cause collision with the vehicle on the rear. It requires a skilled driver to coordinate between the clutch pedal, brake pedal (as well as handbrake in some situations) and accelerator pedal to prevent the vehicle from rolling back while handling such situations. It also leads to clutch disc wear and heating as the driver may tend to slip the clutch to prevent the vehicle from rolling back. Hill hold is a driver assist feature which prevents the vehicle roll back/roll forward during launch operation on uphill/downhill conditions. Hill-hold is offered as an add-on feature on most vehicles equipped with Electronic Stability Program (ESP).
Technical Paper

Implementation of Active & Passive Safety for Mobile Heavy Article Tilter and Positioner (HATP)

2019-01-19
2019-26-0003
Mobile heavy article tilter and positioner (HATP) are special purpose vehicle designed to articulate and positioning of very heavy load within the accuracy of arc minutes and in a stipulated time in fully auto mode. HATP system uses sophisticated electronic controller system to carry out required task in auto mode. This electronic controller system comprises of various types of electronic hardware, software, sensors and actuators. As this system is dealing with heavy load, any failure in any of subsystem of HATP can result into catastrophe. Therefore active and passive safety measure at various level must be incorporated into system which firstly prevents the failure or secondly reduce the effect of failure. The safety system for HATP system has been divided in three major levels: 1. Access level safety 2. Operational safety 3. Preventive safety. All three levels of safety incorporated at appropriate subsystem based on Risk Priority Number (RPN) and failure mode effect analysis.
Technical Paper

Methodology of Virtual and Physical Verification of Symmetrical Design of Tandem Axle’s Input shaft for Mining Application.

2019-01-19
2019-26-0028
Automotive torque transmission shafts, which delivering the maximum torque to wheel hub while transformation of torqueing through driveline components , heavy loading on shaft and possibility of failures in bending is major concerns on heavy duty trucks ( 4 x 2 ) in mining. Need to be getting maximum strength of shaft within optimized packaging of overall design in tandem axle mechanism. An attempt has been made to explore symmetrical cross-sectional shapes to improve bending as well as shear strength performance. Symmetrical shaft concept has been proposed for stiffening to improve the deflection and verification with CAE analysis. A number of design solutions have obtained from the study and a comparison has been made with unsymmetrical design.
Technical Paper

Cold-start WHTC Transient Results on Multi-cylinder Opposed-Piston Engine Demonstrating Low CO2 Emissions while Meeting BS-VI Emission Targets and Enabling Aftertreatment Downsizing

2019-01-19
2019-26-0029
Reducing the greenhouse emissions from on-road freight vehicles to meet the climate change mitigation objectives, has become a prime focus of regulatory authorities all over the world. Besides the India, the United States, the European union, Canada, Japan, and China have already established heavy-duty vehicle efficiency regulations addressing CO2 and NOX emissions. In addition, Argentina, Brazil, Mexico, and South Korea are all in various stages of developing policies to improve the efficiency of their commercial vehicle fleets. For CO2 emissions reduction standards, the U.S. mandates 27% reduction by 2027, EU is calling for 15% reduction by 2025, China - 27% by 2019 over 2012 levels, and India is mandating 10%-15% reduction by 2021 for phase2 of new standard. There has also considerable focus on further reduction in NOX emissions from current levels (0.2 g/hp-hr), to the proposed ultra-low NOx standards (0.02 g/hp-hr) in the U.S. for heavy duty engines by 2024.
Technical Paper

Methodology to Recognize Vehicle Loading Condition – An Indirect Method Using Telematics and Machine Learning

2019-01-19
2019-26-0019
Connected vehicles technology is experiencing a boom across the globe. Vehicle manufacturers started to have telematics devices which leverage mobile connectivity to pool the data. Though the primary purpose of the telematics devices is location tracking, the additional vehicle information gathered through the devices can bring in much more insights about the vehicles. Cloud computing is enabling standard connected vehicle offerings, and on the other hand machine learning and data analytics enables rich customer experience at a very limited cost. From a fleet owner perspective, the revenue and the maintenance costs are directly related to the loading conditions of the vehicle. This could help in efficient planning on vehicle sharing, drive mode selection and proactive maintenance. A common approach to vehicle load condition detection is by using costly sensors. This paper explores a possibility of detecting vehicle load conditions without making use of any additional sensors.
Technical Paper

A Method to Evaluate Impact of Power Steering on Fuel Economy and Optimization

2019-01-19
2019-26-0309
Vehicle manufacturers strive hard to achieve best in class fuel economy. Apart from light weighting of the structures, driveline optimization and reduction of tire rolling resistance, tapping of parasitic losses is also important and helps to optimize the design of auxiliary power consuming systems. One of such system studied in this work is power steering system. The evaluation of deterioration in the fuel economy of the vehicle due to implementation of power steering system on one of the small commercial vehicle is carried out using multiple virtual simulation tools. Virtual route profile is modelled using longitude, latitude and altitude data captured through GPS and steering duty cycle is mapped in terms of steering rotation angle. A system level model of hydraulic power steering system is developed. This model is used to calculate transient hydraulic pump operating power for the given steering rotation angle input which provides power steering pump duty cycle.
Technical Paper

Operational Deflection Shapes & Resonance Analysis Using Road Simulator

2019-01-19
2019-26-0323
In today’s competitive world to stay in the commercial vehicle business, technological advancement is vital. Understanding the various operation modes of a vehicle considering the vibration becomes essential for developing a vehicle free from failures. ODS analysis is a method which is used to visualize the vibration pattern of a vehicle when influenced by known external operating forces. They provide very useful information for understanding and evaluating the behaviour of the vehicle. This paper discusses about the experiments carried out on School bus. It details the process of data collection at varying frequency input, understanding the modes at various frequencies, identifying the resonant frequency of various components, understanding the comparison between road inputs and resonance frequencies and the transfer of vibration (Transmissibility) from one component to another.
Technical Paper

Wheel Durability and Life Improvement - Valve Hole Position Optimization in Commercial Vehicle Wheel Using Segmental Loading Conditions - FEA Approach

2019-01-19
2019-26-0316
In Automotive, Steel wheels are exponentially replaced by Aluminum wheels because of its feather light, agile performance and better acceleration. One such widely used size is 11.75 x 22.5 wheels for trucks and trailer segment. During the design stage of 11.75 x 22.5 wheel, the valve hole was placed away from the stress concentration zone to reduce the stress on the holes and also the design was validated through all conventional wheel rim testing methodology’s (Like CFT, RFT and Bi-axial) and the wheel passed all the test requirements. During the field trials, failures were observed as noticed on the valve holes, despite of this hole was away from stress concentration region. Understood from the field trials that, the regular testing was not able to simulate the real field conditions for this particular size and changed the boundary condition in our FEA to simulate the actual conditions.
Technical Paper

Virtual Validation of Truck Chassis Using Wheel Force Transducer Data

2019-01-19
2019-26-0332
Lot of CAE based evaluation methods and loadcases are available which are derived from acceleration data, strain data acquired on chassis over proving ground or generic gravity loads based on experience. These methods are having certain advantages like faster concept level evaluation, broader perspective and confidence on concept design. But there are few limitations of using these methods like these loadcases are not able to capture all the failure modes and different combination of wheel loads as per RWUP (real world usage pattern) are unknown. WFT (Wheel force transducer) data will give more realistic loadcases. These forces are acquired on each wheel and in 6 directions (3 translational, 3 rotational). Use of these WFT data can be done in multiple ways. For truck chassis durability simulation, quasi-static analysis approach used.
Technical Paper

A Simplified Method To Form A Passenger/Commercial Vehicle Fuel Economy Test Cycle For Tracks/Autonomous Vehicles

2019-01-19
2019-26-0343
Right now, most of the industries are doing real world fuel economy test of their prototypes/mules by deploying them to city, state highways and national highways to declare their FE value. Which involves lot of unexpected problems, large amount of labor and the worst part is the pollution and traffic. With objectives like reducing testing related fuel consumption (reducing fossils consumption), pollution (worldwide concern), cost and project timeline (a benefit for industries), eliminating variations in driving pattern (abnormality during test) and increasing un-launched product confidentiality, a method to create a simplified drive cycle was formed using large sample space of testing parameters. Among already existing drive cycles, this is different because of a simplified mathematics of error and probabilities for method of cycle creation and it has been correlated with the real-world results.
Technical Paper

Performance Optimization Of Commercial Vehicle Clutch Actuation System

2019-01-19
2019-26-0334
Rapid changes in competitive automotive market trends and customer expectations have forced automobile manufacturers to offer better products with more distinctive features and improved comfort, all at a lower cost. High levels of tactile comfort in the cabin compartment and effortless operation of peripheral controls are some of the important factors under consideration while choosing the vehicle over its competition. In the clutch actuation system, the clutch pedal is the first key customer touch point between driver and vehicle transmission hence its performance is most significant to the overall quality perception and customer appeal. The relevance of the clutch actuation system can be better understood in daily life during heavy traffic conditions where the driver is required to perform frequent gear shifting operations, leading to high usage of the clutch.
Technical Paper

Analysis of Multiple Hybrid Electric Concept in Agricultural Tractor Through Simulation Technique

2019-01-19
2019-26-0243
This paper is about to analysis of multiple hybrid electric concept for different agricultural applications for getting better vehicle efficiency through simulation modelling. Agricultural applications are entirely different from On road vehicle, so obtaining optimized vehicle efficiency was difficult because tractor will be used for different application & usage pattern on the same day. During design concept stage, the current vehicle data will be used to set the required target of vehicle efficiency for hybrid electric vehicle. DOE technique was used to predict the vehicle efficiency by modelling and analysis through AMESim Simulation tool for different hybrid electric types. The results were analyzed with the current vehicle performance. This simulation model integrates the Vehicle, Transmission, PTO, Engine, Hybrid electric model which consists of Motor/Generator, Battery & coupling mechanism, Control Model for both vehicle & hybrid.
Technical Paper

Modeling and Optimization of Exhaust After-Treatment System for a Heavy-Duty Diesel Engine using 1D Simulation

2019-01-19
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 developing 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 analytical methodology for design and optimization of exhaust after-treatment system (EAT) for a heavy-duty diesel application has been performed using GT-Power by understanding its thermodynamic behavior. A two-site, 1D model for a selective catalytic reduction (SCR) catalyst was developed and validated with the experimental reactor data.
Technical Paper

Virtual Simulation, Study of Relative Sensitive Parameters and Correlation with Physical Test of Truck Cabin Door Slam Test

2019-01-19
2019-26-0275
Door slam test is one of the important durability test in door design and development. Door require to meet performance parameters like it should close properly (no metal to metal contact), there should not be any leakage, closing operation should be smooth & with minimal effort, it should survive the life of the vehicle. Virtual simulation of door slam test, correlation with physical test results and effect of various parameters like seal stiffness is demonstrated in this study. Door Slam Analysis is carried out in the solver LS-Dyna before physical test. This not only helped us in avoiding the initial design flaws, but supported in deciding door latch position, effect of mass distribution in the door and the study of force distribution in Primary seal, Secondary seal and door latch. Looking at the complexity of the analysis, achieving good results with logical energy balance were difficult. Primary and secondary seals played a critical role in the analysis.
Technical Paper

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

2019-01-19
2019-26-0270
Selective Catalyst Reduction (SCR) is a key technology in achieving BS VI NOx emission norms in Heavy Duty Diesel (HDD) commercial vehicle segment. Indian automotive industry is on the path of adapting SCR only or SCR + EGR strategy with Cu-Zeolite as the catalyst material, considering stability required during DPF regeneration. Since SCR conversion efficiencies are temperature dependent, it is very crucial to achieve correct temperatures upstream of SCR. This is also critical in order to minimize Urea deposition. In addition, achieving faster light off temperatures for urea dosage in cold WHTC is the most challenging task. Therefore, right thermal management strategy has become a key aspect for catalyst performance and in a way achieving legislative emission norms.
Technical Paper

Life Estimation of Vehicle Sub-Systems Using Vibrational Fatigue

2019-01-19
2019-26-0291
Most popular practice for analyzing the Subsystem failures in commercial vehicles is physical testing. These physical tests are carried out by three tests; Endurance testing, Accelerated Endurance Testing & Rig test simulation. All the three methods are costly and repetitive iterations of these tests is not economical. Therefore, in our organization, we established a method in virtual domain in order to reduce the repetitive iterations & also reduction in time consumed per iteration. General practice in our organization for FEA calculation was inclusive of Model preparation, Transient analysis using Nastran. The results from the Transient analysis are used for performing fatigue analysis in FEMFAT software. In this process, Transient analysis & Model preparation are very much time consuming processes.
Technical Paper

Engine Braking: A Perspective in Terms of Brake Power

2019-01-19
2019-26-0288
Engine braking is a supplemental retarding technology in addition to foundational friction brake in commercial vehicles. This technology is in use with the Europe & Americas for several decades now. In engine braking, the engine acts as a compressor, thus producing the required braking power. The braking power is generated by either reducing the volumetric efficiency or increasing the pressure difference across the cylinder. This is usually achieved by using exhaust valve lift modulation. There are dominantly two types of engine brakes viz. bleeder brake and compression release brake. The present work uses GT-Power® model to study the braking performance of a 4 cylinder, medium duty diesel engine at different engine RPMs and valve lifts. The work brings out a comprehensive understanding of different lift events and its effects on braking performance.
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