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Technical Paper

Research on Real-time Obstacle Avoidance by Deceleration and Lane-changing Trajectory Planning and Tracking Strategy Based on Dual Algorithm Control

2021-10-11
2021-01-1262
Aiming at the problem of poor robustness after the combination of lateral kinematics control and lateral dynamics control when an autonomous vehicle decelerates and changes lanes at a certain distance. This paper proposes a trajectory determination and tracking control method based on a PI-MPC dual algorithm controller. In order to describe the longitudinal deceleration that satisfies the lateral acceleration limit during a certain distance of lane change, firstly, a fifth-order polynomial and a uniform deceleration motion formula are established to express the lateral and longitudinal displacements, and a model prediction (MPC) controller is used to output the front wheel rotation angle. Through the dynamic formula and the speed proportional integral (PI) controller to control and adjust the brake pressure.
Technical Paper

Development of a Modeling Approach to Numerically Predict Filtration Efficiencies of Brake Dust Particle Filters

2021-10-11
2021-01-1285
According to the European Environment Agency, air pollution is the biggest environmental health risk in Europe. Since traffic is one of the main contributors of fine dust, technical solutions are necessary to reduce the particulate emission footprint of vehicles. Also the Health Effects Institute hosted recently an international workshop on non-tailpipe emissions. Brake dust filtration concepts have proven to be a promising solution to significantly reduce fine dust emissions from brakes directly at the source. While CFD simulations for inner-ventilated brakes have become state-of-the-art, a holistic models from particle generation and emission to particle dynamics in the vicinity of the brake is not yet available. However, a good modeling approach of particle tracks is essential to predict filtration efficiencies of brake dust particle filters.
Technical Paper

Parametric Optimization of Friction Stir Welded AA2024 using Regression Methods

2021-10-01
2021-28-0223
In this study, a model to optimize the friction stir welding parameters which were rotational speed, welding speed, axial force, tool pin profile, and tool material was established. The target of any design is to maximize the welded properties either to get the base metal properties or higher than that. The model constructed is the result of various regression methods which are quantified for adequacy. In this model, we have taken three levels of varying shoulder diameters, rotation speed, welding speed, tilting angles. A mathematical model is developed for the effect of four process parameters at three levels using response surface methodology (RSM). Analysis of variance (ANOVA) technique is used to check the adequacy of the developed mathematical model. The experimental and predicted values of the mechanical properties are correlated.
Technical Paper

Integrated exhaust manifold design & optimization of it through HCF and LCF simulations for a BS6 compliant Diesel engine

2021-10-01
2021-28-0168
This paper discusses design aspects of an integrated design of exhaust manifold with turbocharger for a 3 cylinder diesel engine, simulation activities (CAE and CFD), and validation of manifold while upgrading to meet current BS6 emissions. Exhaust after-treatment system needs to be upgraded from a simple DOC (Diesel Oxidation Catalyst) to a complex DOC+sDPF (Selective catalytic reduction coated on Diesel Particulate Filter) to meet the BS6 emission norms. To avoid thermal losses and achieve a faster light-off temperature in the catalyst, the exhaust after-treatment (EATS) system needs to be placed close to the engine – exactly at the outlet of the turbocharger. This has given to challenges in packaging the EATS. The turbocharger in case of BS4 is placed near the 2nd cylinder of the engine, but this position will not allow placing the BS6 EATS.
Technical Paper

A Unique Methodology to Improve the Clutch Pedal Characteristics of a Compact Sports Utility vehicle

2021-10-01
2021-28-0243
Clutch characteristics play a vital role in ensuring a smooth and comfortable customer experience of any vehicle. The expectation is to have an optimized clutch pedal effort, reduced pedal travel, adequate modulation zone and a smooth and quick pedal returnability. However, achieving all these customer requirements is extremely challenging in some cases. In the present work, the authors discuss on improving the clutch pedal characteristics of a compact sports utility vehicle (SUV by adapting a unique approach of combining a dual torsion spring (DTS) and a return spring (RS). DTS is widely used in the clutch pedal to improve the pre-load at zero travel (1.5 kg to 2.0 kg) to improve the pedal returnability in the free-play zone. Moreover, it is also quite helpful to reduce the peak pedal effort by giving a positive assistance.
Technical Paper

Optimization of Spring-Damper orientation in Double-Wishbone type Suspension geometry using Genetic Algorithm in Python

2021-10-01
2021-28-0256
The orientation of the spring-damper system in a suspension geometry is a critical but hidden factor in vehicle performance characteristics. Spring and damper mounting characteristics are the significant factors to ensure proper contact of the tire with the ground, maintain ride height, minimize forces on spring, smooth ride, and driver comfort, as varying stiffness for spring orientation will affect the acceleration gain due to road excitation. Determining the spring orientation is conventionally a long and iterative process that involves lots of computational simulations and analytical expressions that should align with the practical vehicle constraints. Due to numerous possible orientations, the designer would randomly pick the orientation and do the simulation, which reduces the solution's reliability and the better solutions remain unexplored.
Technical Paper

EXPERIMENTAL STUDY ON SS-304 SHEET METAL FOR BENDING PROCESS OPTIMIZATION USING RESPONSE SURFACE METHOD

2021-10-01
2021-28-0268
In industry, productivity is based on various manufacturing processes. Bending the Sheet metal process is a type of forming process that has been used by the wide range in industries. There are several tangible and intangible factors affecting the production rate during the bending process. Spring back is one of the severe factors which affects the production rate, especially in stainless steel material. The spring back is mostly affected by material properties, sheet thickness, bending radius, die sizes and component geometry. In this paper, the spring back is studied by the effect of various parameters such as rectangle / oblong slots with varying pitch distance and without slots and bending time in the stainless steel material 304 grade in V-air bending machine. The experimental data are evaluated by using the Response Surface Method and conclusions are drawn. Finally found that explored results have the betterment of the production rate with connection to spring back.
Technical Paper

Experimental Analysis on Wire Electrical Discharge Machining of Nickel Alloy Using Taguchi based Grey Relational Analysis

2021-10-01
2021-28-0273
Nickel is one of the difficult to machine materials and exclusively employed in high temperature environments. This alloy possesses better strength and lesser thermal coefficient which makes the poor machining performance in conventional methods of machining. For overcoming such kind of demerits, nontraditional machining methods have been identified. Wire Electrical Discharge Machining (WEDM) is one among the advanced methods that is developed from the concept of Electrical Discharge Machining process that is predominantly engaged for machining of harder materials and also for producing intricate shapes. This present exploration deals about an experimental study on WEDM of nickel alloy and also mainly concentrating on the optimization of process variables using Taguchi based grey approach. The experimental trials are devised by Taguchi’s experimental design approach and process variables are analyzed by Taguchi’s single response analysis.
Technical Paper

Machine Learning based Operation Strategy for EV Vacuum Pump

2021-09-22
2021-26-0139
In an automobile braking system, Vacuum pump is used to generate vacuum in the vacuum servo or brake booster in order to enhance the safety and comfort to the driver or operator. The vacuum pump operation in the braking system varies from conventional to electric vehicles. The vacuum pump is connected to the alternator shaft or CAM shaft in a conventional vehicle, operates continuously at engine speed and supplies continuous vacuum to the brake servo irrespective of vacuum requirement. To sustain continuous operation, these vacuum pumps are generally oil cooled. Whereas in electric vehicles, the use of a motor-driven vacuum pump is very much needed for vacuum generation as there is no engine present. Thus, with the assistance of an electronic control unit, the vacuum pump can be operated only when needed saving a significant amount of energy contributing to fuel economy and range improvement and emission reduction.
Technical Paper

OPTIMAL TIME-WINDOW BASED FORMULATION FOR AUTONOMOUS VEHICLE PATH PLANNING

2021-09-22
2021-26-0124
In last few years, research and development efforts on autonomous vehicle engineering technology has advanced significantly (see for instance, Waymo LLC [1], Tesla Research Corp.). Similarly, the support of sophisticated computational algorithms for operations of such autonomous vehicles are also advanced [2]. This has enabled imparting autonomy as a viable alternative for vehicle operation even in complex environments. It may also be noted that, preference to autonomous vehicle technology fostering is due to their ability to achieve assigned tasks in a predefined time frame with minimal human intervention. Hence, it is important to have a solution scheme which shall provide a means to determine a path plan ensuring the usage of an autonomous vehicle optimally to reduce the overall operation time while minimizing its operating costs. Saying this, the problems like computational complexity, high number of constraints and robustness of the system arise.
Technical Paper

FEA based methodology to optimize sealing performance in Fuel vapor emission valves

2021-09-22
2021-26-0203
As per current global trends, low tailpipe and evaporative pollutant emissions is major focus area in automotive development. This has led to imposing stringent emission limits on both tailpipe and evaporative emission norms. In field of evaporative emissions, the fuel valves must meet zero-leak of fuel to canister requirement under different operating conditions. Corresponding sealing design iterations and evaluating the performance thru lab testing is time and cost consuming. Present study considers FEA based sealing analysis considering elastomeric-plastic interface using ANSYS. The designs are evaluated by comparing surface contact of seal with valve orifice. In present study, different combinations of shape, size of plastic and elastomeric parts, material stiffness, axis position of elastomeric & plastic parts and use of supporting structure for elastomeric parts are evaluated.
Technical Paper

A Vehicle Pass-by Noise Prediction Method Using Ray Tracing with Diffraction to Extend Simulation Capabilities to High Frequencies

2021-09-22
2021-26-0264
Predicting Vehicle Pass–by noise using simulation enables efficient development of adequate countermeasures to meet legislative targets while reducing development time and the number of physical trial-and-error prototypes and tests. It has already been shown that deterministic simulation methods such as the Boundary Element Method (BEM), which may also include directivity of sources, can support the trim package optimization process for Pass-by noise, especially for low to mid frequencies. At higher frequencies, the Ray Tracing technique, can represent an efficient alternate providing options to trade off speed versus accuracy compared to wave based technique such as FE/BEM. This paper presents a Ray Tracing approach with high order diffraction effect. Moreover, source directivity and sound package effect are accounted for.
Technical Paper

Ride and Comfort Measurements - A Challenge of Subjective & Objective Correlation

2021-09-22
2021-26-0445
Traditionally, vehicle ride and comfort is evaluated, subjectively as well as objectively. Based on the outcome of subjective and objective tests, it is refined by optimizing primary suspension system, secondary suspension system, seating system, rubber bushings, frame and BIW for mass, stiffness, damping, geometry etc. Many a times, the subjective assessment results stands in contradiction to the objective assessment results; emphasizing need for having good correlation between subjective and objective test results. In such cases, it is ambiguous to decide suitable design refinement action and can lead to no improvement situation. Hence, it is very much essential to have concurring test procedures for subjective and objective ride evaluation. This paper describes a novel methodology to address the above said challenge. There are defined set of test events and measurement data points to be used in subjective and objective testing.
Technical Paper

Simulation based approach to study the effect of hypoid gear manufacturing variability on In-cabin noise

2021-09-22
2021-26-0270
With increase in demand for quieter product and reduction in masking noise, axle whine management plays a crucial role in the early product development process. Whine is tonal in nature and humans are more sensitive to tonal memory, hence this makes user to experience a very unpleasant ride which in turn results in bad product credibility. Dynamic mesh force excitation is the cause of the axle whine noise. Critical factors in consideration are micro-geometry design, operating loads and associated misalignment's, operating temperature & bearing pre-load, and the structural response that transfers mesh force excitation to the occupant's ear. Consideration of gear micro-geometry variability influence on driver ear noise is one of the most crucial aspect of robust axle whine management plan. This work demonstrates influence of gear manufacturing variability on hypoid gear transmission error, dynamic mesh force, pinion nose vibration and resulting axle whine noise in driver ear.
Technical Paper

Door Seal Behavior Prediction and Enhancement in Performance Using Digital Simulation

2021-09-22
2021-26-0387
Automotive door seal has an important function which is used extensively where interior of the vehicle is sealed from the environment. It must be functional and cohesive with the body design of the vehicle. Poor door seal system design will cause water leakage, wind noise, hard opening or closing of doors, gap and flushness issue which impair customer’s satisfaction of the vehicle. Moreover, improper design of seal can lead to difficulty in installation of door seal on body panel. The design prudence and manufacturing process are important aspect for the functionality and performance of sealing system. However, the door sealing system involves many design and manufacturing variables. At the early design stage, it is difficult to quantify the effect of each of the multiple design variables.
Technical Paper

Performance evaluation of degas tank

2021-09-22
2021-26-0475
This paper presents the free surface behaviour of liquid while degas tank bottle is in service. The liquid in the degas tank is subjected to exceed the mean line in the service and the fluid levels in all chambers varies as there is continuous movement and sloshing in the fluid. The objective of this work is to optimise the baffle design such that the fluid level in the tank does not exceed the mean line in service and fluid in the all chambers need to be maintained at same level. The scope of work is also to enhance the tank baffles which will dampen the fluid sloshing and the fluid de-aeration should be done effectively to avoid any possible structural damage. The simulation of liquid free surface behaviour under uniform acceleration is done using STAR CCM+ software. A numerical model is developed based on Volume of Fluid (VOF) technique to track the free surface motion of liquid. The explicit time discretization scheme is employed to solve the volume fraction equation.
Technical Paper

Virtual tuning and optimization of two wheeler suspension through MBD simulations

2021-09-22
2021-26-0348
The design and tuning of stiffness and damping parameters of the suspension system is an essential step in arriving at the optimal riding comfort for a two wheeler. The conventional method of suspension design involves selecting baseline values of suspension parameters through bench-marking of similar vehicles, followed by extensive real life tests to tune these parameters over different load, speed and track conditions. This conventional approach is often time consuming and heavily dependent on physical prototypes of suspension. With the advent of tools to run optimization on Multi-Body Dynamic (MBD) simulations, a near complete tuning of suspension parameters can be performed entirely in the simulation domain. This paper presents an integrated approach towards the design and tuning of suspension stiffness and damping parameters using MBD simulations, by employing fully parameterized suspension stiffness and damping curves in the optimization process.
Technical Paper

Investigation of Sink Butt Welding for 120 Degree Door Frame Design

2021-09-22
2021-26-0440
This paper deals with Vehicle Door 120 Degree joint Rust issue and water leak faced in most of SUV cars. Generally based on vehicle segment its styling curves and exterior design are defined. A Sedan or Hatchback is provided with curves to show its fluidic design but a SUV is provided with Straight lines to show its aggressive look. In existing condition Weld bead is added to prevent rust in joint area, but still improper seating of weather strip on Weld bead cause water leak. Door A Pillar Frame and Horizontal Frame match at 120 degree Joint Edges are chamfered straight to match perfectly. Weld bead runs over the matching profile to join it. But Weld Bead project over the Frame surface and affects Weather strip seating & results in poor sealing. Adhesive added for better sealing also follows the same path on bead and create a path way for water entry. Thus in long run this water stagnates and cause chronic Rust issues in frame.
Technical Paper

Systematic Approach for Optimizing Tailgate Stoppers and their Location to Prevent Squeak and Rattle

2021-09-22
2021-26-0285
Tailgate stoppers play vital role in exerting pre-load on the tailgate latch mechanism and also restrict the relative motion of the tailgate against vehicle Body in White (BIW). These stoppers act as dampeners and reduce the transmissibility of vibrations thereby reduce the risk of Squeaks & Rattles (S&R) noises. These noises from tailgate are most annoying to the rear passengers in the vehicle and are recurring in nature. S & R risk simulations reduce cost by eliminating most of the design changes that are required in the physical prototype at the later stages of product development cycle and save time. The risk evaluation in the simulations is based on the relative displacement at the interfaces of two components. These interfaces are represented by Evaluation Lines (E-Lines) which are nothing but a series of nodes at the interface locations. The tailgate stoppers are modeled using a spring element with stiffness calculated from force deflection experiments.
Technical Paper

Implementation of Atkinson effect for improved fuel efficiency of Gasoline Engine using 1-D simulation software and its validation with experimental data

2021-09-22
2021-26-0053
In order to meet the challenges of future CAFE regulations & pollutant emission, vehicle fuel efficiency must be improved upon without compromising vehicle performance. Optimization of engine breathing & its impact on vehicle level fuel economy, performance needs balance between conflicting requirements of vehicle Fuel Economy, performance & drivability. In this study a Port Fuel Injection, naturally aspirated small passenger car gasoline engine was selected which was being used in a typical small passenger car. Simulation approach was used to investigate vehicle fuel economy and performance, where-in 1D CFD Engine model was used to investigate and optimize Valve train events (Intake and exhaust valve open and close timings) for best fuel economy. Engine Simulation software is physics based and uses a phenomenological approach 0-D turbulent combustion model to calculate engine performance parameters. Engine simulation model was calibrated within 95% accuracy of test data.
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