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In recent years, the push for reduced product development timelines has been more than ever with significant changes in the automotive market. High electrification, intelligent vehicle systems and increased number for car manufacturers are a few key drivers to the same. The front loading of development activities is now a key focus area for achieving faster product development. From vehicle dynamics point of view availability of subjective evaluation feedback plays a key role in optimization various system specifications. This paper discusses an approach for front loading through parallel development of the tire and vehicle chassis system, using advanced simulation and driving simulator technology. The proposed methodology uses virtual tire models which in combination with real-time vehicle model enables subjective evaluation of vehicle performance in driver-in-loop simulators.

A 4 wheeled vehicle with X-split brake configuration, in hydraulic circuit failed condition will have a behavior of induced sway due to braking force variation in the front and rear diagonally. With increasing vehicle speed, engine power & customer expectations, the situation becomes more critical and challenging in designing a brake system which caters in meeting the homologation requirement at an expense of vehicle sway within controllable limits of driver / customer. This paper proposes a novel approach & methodology to overcome the above situation by predicting the effect of brake force distribution variation on the vehicle swaying behavior during circuit failed braking condition. This study will quantify vehicle sway, caused due to imbalance in brake force distribution during a circuit failed braking event on X Split configuration vehicles.

Determination of vehicle specifications (for example, powertrain sizing) is one of the fundamental steps in any new vehicle development process. The vehicle system engineer needs to select an optimum combination of vehicle, engine and transmission characteristics based on the product requirements received from Product Planning (PP) and Marketing teams during concept phase of any vehicle program. This process is generally iterative and requires subject matter expertise. For example, accurate powertrain sizing is essential to meet the required fuel economy (FE), performance and emission targets for different vehicle configurations. This paper analyzes existing vehicle specifications (Passenger Cars/SUVs - Gasoline/Diesel) in different automotive markets (India, Europe, US, Japan) and aims to determine underlying trends across them.

Automotive OEMs are aggressively using different materials for interiors due to value proposition and variety of options available for customers in market. Excessive usage of different grade plastics with zero gap philosophy can cause stick slip effect leading to squeak noise. Even though systems and subsystems are designed using best practices of structural design and manufacturing tolerances, extreme environmental conditions can induce contacts leading to squeak noise. Appropriate selection of interface material pairs can minimize the possibilities of squeak conditions. Stick-slip behavior of different plastics is discussed in the present study, along with critical parameters during material compatibility testing in a tribological test stand. Friction coefficient of different material pairs for a defined normal load and sliding velocity are analyzed for patterns to recognize squeaks versus time.

Light weighting is an effective strategy in increasing energy efficiency in the automotive industry. In this paper, mass reduction with cost benefit was targeted in an exterior trim panel. Polypropylene copolymer (PPCP) compound was developed for a large exterior trim panel (1400 X 700mm) having an integrated grill mesh. The part had challenging requirements in terms of slow speed impact, structural durability, dimensional stability, aesthetics, thermal ageing resistance, cold impact resistance, scratch resistance and weathering resistance. By having ultra-high flow behavior, optimum tensile strength, modulus, impact strength and thermal properties, the PPCP compound met the requirements for a thin wall exterior trim panel with a thickness of 2.6mm. Structural durability of the design was validated by virtual engineering. Part design and material combinations with better tooling design iterations were analyzed by using mold flow analysis.

Turbocharged common rail direct injection engines offer multiple benefits compared to their naturally aspirated counterparts by allowing for a significant increase in the power and torque output, while simultaneously improving the specific fuel consumption and smoke. They also make it possible for the engine to operate at a leaner air/fuel mixture ratio, thereby reducing particulate matter emission and permitting higher EGR flow rates. In the present work, a two cylinder, naturally aspirated common rail injected engine for use on a load carrier platform has been fitted with a turbocharger for improving the power and torque output, so that the engine can be used in a vehicle with a higher kerb weight. The basic architecture and hardware remain unchanged between the naturally aspirated and turbocharged versions. A fixed geometry, waste gated turbocharger with intercooling is used.

Synchronizer design optimization is being prime need for smooth gear shifting and shifting noise. Especially in tractors, synchronizers are subjected to different kinds of loads under various field applications such as Puddling, Cultivation, Haulage, Construction equipment, etc. Also, transmission housings act as a part of chassis of the tractor and hence subjected to sever bending loads. Thus, design & evaluation of tractor transmission, meeting the customer requirement is quite complex. Current trends in product development are driven by shortening development time, reduced cost and first-time-right principle. These above requirements drive tractor manufacturers to put more efforts on delivering quality, robust and reliable transmission assembly in time. Generally the synchronizer packs were validated at sub system level in test rig and further assembled on to the tractor to validate the same in tractor level it requires more time & high cost.

PVC (polyvinylchloride) synthetic leather or called leatherette is being widely used for automotive interior applications for seat cover, gear boot, gap hider, steering wheel and roof liner due to their leather like feel and texture, flexibility, sewability, affordability, and wide design freedom. However, the leatherette construction such as top coating, backing fabric and fabric weaving pattern plays a critical role in the finished leatherette performance for the specific application. This study provides the influence of different coating material and different backing fabric in squeak behavior of gear boot PVC leatherette. The squeak behavior was studied by stick slip test as per automotive engineering requirements, and the response of these coating and fabric surface was measured in the form of Risk Priority Number (RPN).

Fatigue life estimation of automotive components is a critical requirement for product design and development. Automotive companies are under tremendous pressure to launch new vehicles within short duration because of customer’s changing preferences. There is a necessity to have a comprehensive virtual simulation and robust validation process to evaluate durability of vehicle as per customer usage. Test track and field test are two of the most time-consuming activities, so there is a need of simulation process to substitute these requirements. This paper summarizes the overall process of Accelerated Durability Test with measured road loads. Based on category of vehicle, type road profiles and the customer usage pattern, the wheel forces, strains and acceleration are measured which is used to derive the equivalent duty cycles on proving ground. The wheel force transducers (WFT) are used to derive loads for fatigue life estimation.

Among the Original Equipment Manufacturers (OEM’s), comfort, fuel efficiency and safety are the key factors that drive the vehicle business. The main contributors of vehicle comfort are vibration, noise, thermal comfort (temperature), air quality, light, and ergonomics. In this context, compressor noise plays an important role in the comfort of the passengers. Noise can have adverse effect on occupants in the vehicle starting from mild annoyance and may lead to loss of concentration. It is a big challenge for the automotive engineer to find the source of noise and path through which it is transmitted, and eventually to reduce or dampen it during the product development. The objective of this paper is to understand the functioning of various compressor’s noise characteristics in static (i.e. initial engagement of compressor) and dynamic condition (i.e. during compressor running).

This study on optimum magnification at which Retained austenite to be evaluated by comparing the difference in determining the retained austenite in low carbon carburizing alloy steel using the optical metallurgical micrographic method and X-ray diffraction method. The retained austenite phase will be in surface and color is white in nature also its presented in between the martensite needles. It can be distinguished as separate micro-constituents by using image analyzing software. In another method the RA measurements were carried out on the surface by PROTO iXRD Retained austenite measuring system using Cr K radiation. The (211) and (200) reflections of Martensite and (220) and (200) reflections of Austenite were made for this estimation. However, the calculated values of retained austenite by metallurgical microscope in different magnifications are not identical.

During design and development of a cabin for any commercial vehicle, meeting the strength requirements of front impact as per Indian regulation (AIS-029) is a very critical milestone. AIS-029 regulation consists of three destructive tests, i.e. Front Impact Test (Test A), Roof Strength (Test B) and Rear Wall Strength (Test C). Study of energy absorbing front cabin mount, its stiffness balance with chassis and CAE correlation with physical test is demonstrated in this study. [1]

In automotive Body-In-White (BIW) structures, stiffness and the fatigue behavior is greatly influenced by the properties of its joints. Spot welding is one of the most widely used process for joining of sheet metals in BIW. Spot weld fatigue life under Accelerated Durability Test (ADT) is crucial for durability performance of BIW structures. Experience of BIW validations highlighted more number of spot weld failures in CAE when compared to actual tests. Hence, lot of iterations in the form of design modifications are required to be carried out to make these spot welds meet the targets which increases design & development time as well as cost. Current practice uses force-based approach for predicting spot weld fatigue life in CAE. To improve the spot weld fatigue life correlation, extensive study has been carried out on the approaches used for calculating spot weld fatigue life, namely force & stress-based approaches.

The noise and vibration performance of diesel fueled automotives is critical for overall customer comfort. The stationary vehicle with engine running idle (Vehicle Idle) is a very common operating condition in city driving cycle. Hence it is most common comfort assessment criteria for diesel vehicles. Simulations and optimization of it in an early stage of product development cycle is priority for all OEMs. In vehicle idle condition, powertrain is the only major source of Noise and Vibrations. The key to First Time Right Idle NVH simulations and optimization remains being able to optimize all Transfer paths, from powertrain mounts to Driver Ear. This Paper talks about the approach established for simulations and optimization of powertrain forces entering in to frame by optimizing powertrain mount hard points and stiffness. Powertrain forces optimized through set process are further used to predict the vehicle passenger compartment noise and steering vibrations.

Model based calibration is extensively used by the automotive OEMs (Original Equipment manufacturers) because of its correlation accuracy with test data and freezing the operating parameters such as injection timings, EGR rates, fuel quantity etc. The prediction of Brake specific Fuel consumption (BSFC), Exhaust and intake temperatures are very close to test data. The prediction of Brake specific NOx is directionally reliable with acceptable tolerance.

Present day AMT unit uses two high pressure hydraulically operated pistons for select & shift operations which make the unit weigh around 8kg. Besides this it also makes the unit more complex & unreliable with a lot of torque interruption. The use of electrical servo motors steps in here as a better alternative as it provides a more precise and smoother shift. To test this we used a 5-MT Transmission. For the selection, a precise 14.5 degree of twisting was required which was easily achieved by the servo motor. Further, shift of 10.5mm could be made possible by using the motor to shift the rack using a pinion on the shaft. This system then essentially eliminates the whole hydraulic circuit, the housing of actuator pack & power pack making it a simpler unit all together. Thus, it offers an uninterrupted torque path from the engine to vehicle which allows for a seamless gearshift. This seminal paper provides an introduction to the technology together.

Present day AMT unit uses two high pressure hydraulically operated pistons for select & shift operations which make the unit weigh around 8kg. Besides this it also makes the unit more complex & unreliable with a lot of torque interruption. The use of electrical servo motors steps in here as a better alternative as it provides a more precise and smoother shift. To test this we used a 5 Gear-Manual Transmission. For the selection, a precise 14.5 degree of twisting was required which was easily achieved by the servo motor. Further, shift of 10.5mm could be made possible by using the motor to shift the rack using a pinion on the shaft. This system then essentially eliminates the whole hydraulic circuit, the housing of actuator pack & power pack making it a simpler unit all together. A Motor is attached to the output shaft of the Transmission which drives in power while the AMT unit is making transition from one gear to another.

Crashworthiness enhancement of vehicle structures is a very challenging task during the early design development process. Major factors influencing occupant injury in frontal impact are vehicle front crush space, crash pulse severity, restraint properties and occupant packaging space. This paper establishes a methodology to define suitable criterion that will guide the designers to select the optimal values of the above mentioned parameters during the early phase of the vehicle development. The usage of lumped mass models, pulse characterization techniques were explored to validate the results. Efficient crash energy management, the concepts of ride down and restraint efficiency parameters were also discussed in the paper.

In automotive product development, design and development of the chassis plays an important role since all the internal and external loads pass through the vehicle chassis. Durability, NVH, Dynamics as well as overall vehicle performance is dependent on the chassis structure. Even though passenger vehicle chassis has a ladder frame or a monocoque construction, small commercial vehicle chassis is a hybrid chassis with the cabin welded to the ladder frame. As mileage is critical for sale of SCVs, making a light-weight chassis is also important. This creates a trade-off between the performance and weight which needs to be optimized. In this study, a parametric beam model of the ladder frame & the cabin of the vehicle is created in COMSOL Multiphysics. The structure has been parameterized into the long member & crossmember geometry & sections. The model calculates the first 12 natural frequencies, global stiffness, and weight.

In automotive manual transmission gearboxes, the synchronizer rings play a vital role in gear shift operations. The efficiency of the synchronizer ring depends upon the frictional surface geometry. The critical parameter is the synchronizer ring frictional surface circularity. The circularity deviation causes higher synchronizer ring wear and poor cone torque generation. With the current manufacturing methods and the thickness of the synchronizer ring, circularity improvement is a challenge. The synchronizer ring thread turned part is lapped to improve the circularity. Reduction in circularity can be improved by optimizing the lapping operation. In this work, an optimal lapping condition was developed using statistical methods. Taguchi DOE was used to analyze the different parameter combinations along with the noise parameter – different ranges of circularity variation in turning operation. This helps to find the best lapping parameter settings to improve the reduction in circularity.