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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.

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.

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).

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.

Each OEM has a distinguishing drivability character that defines its image in the market to achieve brand differentiation. Drivability is one of the important factors along with fuel economy that determines the success of a vehicle vis-à-vis its competitors. It can be said that the need for good drivability among customers is increasing day by day similar to the need for high fuel economy. Drivability is the response that a vehicle delivers to the inputs of the driver which are mainly accelerator, brake, clutch, gear and steering. The dynamic response of the vehicle is mainly in terms of velocity and acceleration. The way the response is delivered will characterize the drivability of a vehicle. The drivability event discussed in this paper is throttle tip-in response which is one of the critical evaluation factors for defining the character of a Sports Utility Vehicle.

One of the critical challenges for transmission design is to predict the gear shift dynamics accurately and to ensure smooth gear shift quality for different driver behaviors while shifting. This calls for detailed understanding of the RWUPs. Through prototype testing, understanding the influence of different parameters is costly and time consuming. Also, the testing does not provide necessary visualization of exact physics and the identification of issues is difficult. One of such typical concerns is shift shock while shifting the gear. Sudden gear engagement or disengagement leads to impact torque in drivetrain during shifting of gears, which in turn results in winding and unwinding of powertrain due to vehicle Inertia. This induces noise and vibration that affects driver comfort. The paper presents, the methodology to frontload prediction of dynamics of gear shifting that leads to shift shock behavior.

With an intense competitive automotive environment, it becomes imperative for any OEM to launch their products into the market in a short span of time & with a ‘First Time Right’ approach. Within the current scenario in the Automotive Industry, the selection of optimum set of hard points and wheel geometry often becomes an iterative or a trial-and-error process which is both time consuming and involves higher development cost as there may be instances where 2 to 3 sets of iterations are needed before specification is finalized for production. Through this paper, an attempt has been made to develop a methodology for deciding wheel geometry parameters (covered in the later section of this paper like Caster, Camber, Mechanical trail, etc.) [1, 2, 3, 4] for a three wheeled vehicle as a First Time Right (FTR) approach to cut down on conventional, expensive & time-consuming iterative approach.

Vehicle pull during braking can be defined as the deviation of vehicle travel from intended path of the vehicle by a margin of half a wheel track or more. It is a dynamic phenomenon with very complex inter-dependencies among the combined functioning of various aggregates such as steering system, suspension system, axles, and brakes. The problem is aggravated with shorter wheelbase & higher CG (Centre of Gravity) height, where the instantaneous load transfers are sudden and of relatively high magnitude which can lead to a combination of forces that are responsible for vehicle drifting or pulling to anyone side of centre-line travel. Vehicle with shorter wheelbases, high GVW and high CG heights are more prone to this unstable behaviour due to sudden change in dynamic forces acting on the tires while turning and braking.

Agriculture tractor industry is highly competitive in the current market scenario with global majors competing in various markets. A tractor having an optimum design is of prime importance to keep the cost low while providing higher value to the customers. Technology advances in instrumentation methodology and data acquisition helps not only in providing the right inputs for the design of a component/system but also very much useful for design/system optimization. Front Axle Support of an agricultural tractor is one of the structural member which is connected to the Chassis which is called skid of the tractor to which the Front Axle is mounted through Pillow block (Plummer block) arrangement to facilitate axle oscillation about the tractor longitudinal center line. Front ballast weights are mounted on a bracket which is intern mounted to the front axle support to maintain the required front reaction in various agricultural operations.

Gears are one of the vital components to transmit torque efficiently. Helical gears are chosen as they transmit higher torque with lesser noise compared to spur gears of same size. All new age gearboxes require to transmit maximum torque with minimum packaging space available to improve torque density. Ways of reducing weight are using lesser density material, decreasing centre distance, and thereby reducing pitch circle diameter of all gears, etc. However, they will also affect torque carrying capacity of gearbox which can lead to gear failure in conventional transmission architecture gearboxes with input reduction method. In input reduction method, torque gets multiplied from input shaft to countershaft. Countershaft torque is multiplied to output shaft gears requiring higher torque capacity gears on output shaft. In this research, output shaft reduction architecture is proposed to avoid torque multiplication from input shaft to countershaft gears.

Increasing of automatic transmissions in passenger cars is based on pleasure of driving, smooth acceleration and easy operation makes the customer satisfaction. Challenges beyond 2020 is BS VI emission norms in India - a very tough goals on CO2& NOx reduction in Gasoline & Diesel vehicles. But its setback in lower fuel economy. To support & enhance fuel economy in Automatic transmissions as part of drivetrain technologies, this article discusses about the power losses in torque converters and experiments on the actual Automatic transmission (AT) vehicle on-road to understand the real city driving behavior in the aspects of gear utilization & gas pedal utilization throughout the entire traffic conditions. With that data research, slip area and slipping conditions is determined & clutch slip control is enabled at area in torque converter by ensuring that NVH parameters are not affected.

A critical requirement for product design and development is meeting vehicle dynamic performance. Customers changing needs puts tremendous pressure on automotive businesses to launch new vehicles within short durations of time. This makes it mandatory to have a wide-ranging virtual simulation and vigorous validation process to provide best in class ride and handling performance of vehicles. Physical testing of prototypes is the most time-consuming activity, so there is a need of front loading to substitute these requirements at the initial stage of the development cycle. This paper summarizes the overall process for front loading vehicle dynamics requirements during basic architecture definition using virtual simulation. Basic dimensions, CG, weight distribution and steer angle of the new vehicle are derived using concept calculations based on benchmark vehicles. Vehicle dynamics trials are then done for the benchmark vehicles.

The given paper presents the main elements of frictional power loss distribution in an automotive axle for passenger car. For reference two different axles were compared of two different sizes to understand the impact of size and ratio of gear and bearings on power loss characteristics. It was observed that ~50% of total axle power loss is because of pinion head-tail bearing and its seals, which is very significant. Roughly 30% of total power loss is contributed by pinion-ring gear pair and differential bearings and remaining ~20% by wheel end bearing and seals. With this study the automotive companies can take note of the area where they need to focus more to reduce their CO2 emissions to meet the stringent BS6, CAFÉ and RDE emission norms.

The present quiet and comfortable automobiles are the result of years of research carried out by NVH engineers across the world. Extensive studies helped engineers to attenuate the noise generated by major sources such as engine, transmission, driveline and road excitations to a considerable extent, which made other noise sources such as intake, exhaust and tire perceivable inside. Many active and passive methods are available to reduce the effect of said noise sources, but enough care needs to be taken at the design level itself to eliminate the effect of cavity resonances. Experimental investigation of cavity resonances of real systems is necessary besides the FEA model based calculations. Acoustic cavity resonance of vehicle sub systems show their presence in the interior noise through structure borne and air borne excitations. Cavity resonances for some systems e.g. intake can only be suppressed through resonators.

There is a growing need for the accurate Computer Aided Engineering (CAE) models for vehicle performance evaluation. The reduced product development time and complexity of the vehicle evaluation demands accurate prediction with CAE models. Vehicle dynamics performance evaluation is very critical in vehicle development process, which require very accurate vehicle and tire models. The tire characteristics are represented as mathematical, physics based and empirical models. There are different types of tire models exist like Fiala, PAC, SWIFT and FTire etc, which can be used for vehicle handling, ride and steering performance evaluation. There is a need to study and understand these tire models before applying to specific vehicle dynamic performance. There is a challenge to get the tire models as tire modeling require lot of tests and time consuming.

The brass synchronizers are not resistant to abusive conditions of gearbox operations, but they are very durable and cheap when used on their favorable material property working limit. The main failure which can occur in the gearbox due to the synchronizer is crash noise. During gear shifting the gear crash will create high discomfort for the driver and must apply high force to change the gears. The main factors which contribute to the crash phenomenon are the insufficient coefficient of friction, high drag in the system, and high wear rate of the synchronizer rings before the intended design life of the synchronizer. The brass synchronizers were tested on the SSP-180, ZF synchronizer test rig to know the effect of the synchronizer performance parameters like the coefficient of friction, sleeve force, slipping time as well as durability parameters like wear rate when the operating temperature of the oil is changed.

Automotive steel wheel is a critical component for human safety. For validating steel wheel various tests will be performed at component and vehicle level. Cornering test performed at vehicle level is one of the tests, where wheel will be validated for high cornering loads. Cornering test performed at vehicle level consists of three different events i.e., rotations of vehicle in track1, rotations of vehicle track 2 and rotations of vehicle in track3. As wheel will experience different loading in each of the events of cornering test, correlating the virtual Finite Element Analysis (FEA) with physical test is quite challenging. If in FEA we can predict the damage and life very near to the physical validation, we can create a safe wheel for high cornering loads without any test concerns. Vent hole shape and Hat depth are two important aspects in wheel disc design. Vent hole shape and size will influence the heat dissipation of braking.

Suspension plays a crucial role in stabilizing, comfort and performance of a vehicle. During vehicle braking operation, load transfer happens from rear axle to front axle resulting in shifting of vehicle’s center of gravity towards vehicle front for a momentarily duration which is called diving. This phenomenon leads to dropping of traction at rear wheel end resulting in lifting of rear axle with front wheel as pivot. This causes increase in front to rear weight ratio of vehicle system and compromising driver safety due to skidding and locking of rear wheel-end. To minimize this phenomenon’s affect, optimum anti-dive suspension geometry is used to have better rear wheel end traction resulting in improved braking stability.