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Today’s automotive world has moved towards an age where safety of a vehicle is given the topmost priority. Many stringent crash norms and testing methodology has been defined in order to evaluate the safety of a vehicle prior to its launch in a particular market. If the vehicle fails to meet any of these criteria then it is debarred from that particular market. With such stringent norms and regulations in place it becomes quite important on the engineer’s part to define the structural requirements and protect the space to meet the same. If the concept level platform definition is done properly it becomes very easy to achieve the crash targets with less cost and weight impact.

In present study a comparative investigation and correlation attempted on small scale vehicle model for aerody-namic drag performance at small scale wind tunnel test facility in India vs full vehicle tested at globally know and accepted full scale test facility in Pininfarina, Italy. Current investigation aims to assess the small-scale wind tunnel suitable for testing 1:3 small scale car models A scale model of 1:3 scale size was tested in small scale wind tunnel (at IISC,Bengaluru, India) having test section area of 11.68 Sq. m. To understand the overall vehicle aerodynamic drag performance small scale model was test-ed for different configurations such as baseline, spoiler removal, underbody cover and different yaw condition. To understand the correlation between small scale vs full vehicle’s aerodynamic performance one actual vehicle was also tested at full scale wind tunnel Pinifarina Italy.

The bolted joints in suspension systems are subjected to severe external service loads during vehicle operation. To prevent the loaded joint from loosening and allowing it to retain its potential energy stored during assembly, a holistic design approach is needed. This paper explains the methodology to design and optimize bolted joints for the suspension systems of a modern 7-seater sports utility vehicle.

The ever-increasing customer expectations put a lot of pressure on car manufacturers to constantly reduce the noise, vibration, and harshness (NVH) levels. This paper presents the holistic approach used to achieve best-in-class NVH levels in a modern high-power density 1.5 lit 4-cylinder diesel engine. In order to define the NVH targets for the engine, global benchmark engines were analysed with similar cubic capacity, power density, number of cylinders and charging system. Moreover, a benchmark diesel engine (considered as best-in-class in NVH) was measured in a semi-anechoic chamber to define the engine-level NVH targets of the new engine. The architecture selection and design of all the critical components were done giving due consideration to NVH behaviour while keeping a check on the weight and cost.

Original Equipment Manufacturers (OEMs) should innovate ways to delight customers by creating affordable products with improved drive experience and occupant comfort. Vehicle refinement is an important initiative that is often take-up by the project teams to ensure that the product meets the customer’s expectations. A few important aspects of vehicle refinement include improving the Noise Vibration Harshness (NVH), ride and handling performance pertaining to the Functional Image (FI) of the product. Optimizing the suspension design variables to meet both ride and handling performance is often challenging as improving the ride will have a deteriorating effect on handling and vice-versa. The present work involves Multi-Objective Design Optimization (MDO) of the suspension system of an automotive Sports Utility Vehicle (SUV) platform considering both ride and handling requirements, simultaneously.

The focus on driver and occupant safety as well as comfort is increasing rapidly while designing commercial vehicles in India. Improvements in the road network have enhanced road transport for commercial vehicles. Apart from the cost of operation and fuel economy, the commercial vehicles must deliver goods within stipulated time. These factors resulted in higher speed of operation for commercial vehicles. The design should not compromise the safety of the vehicle at these higher speeds of operation. The vehicle should obey the driver’s intended direction at all speeds and the response of the vehicle to driver input must be predictable without much larger surprises which can lead to accidents. The commercial vehicles are designed with rigid axle and RCB type steering system. This suspension and steering design combination introduce steering errors when vehicle travel over bump, braked and while cornering.

The stringent emission regulations demand highly complex after-treatment systems. The packaging and functional requirements of the after-treatment system demand very close coupling of the diesel oxidation catalyst (DOC) with the turbocharger outlet. The sealing effectiveness between the turbocharger and DOC is ensured by the V-band grooved clamp along with the suitable gasket. This V-band grooved clamp is widely used in diesel engines due to its ease of assembly and low cost. Since the V-band grooved clamp is subjected to a very high temperature, vibration, thermal shock, a robust and holistic validation is required to ensure the functional and safety requirements. Despite its wide range of applications, the testing and validation methodologies required to effectively validate the strength and other aspects of the clamp are not fully defined. In the present work, the authors discuss the various design validation methods involved during the development of the V-band grooved clamp.

Range anxiety is one of the major factors to be dealt with for increasing penetration of EVs in current Automotive market. The major reasons for range anxiety for customers are sparse charging infrastructure availability, limited range of Electric vehicles and range uncertainty due to diverse real-world usage conditions. The uncertainty in real world range can be reduced by increasing the correlation between the testing condition during vehicle development and real-world customer usage condition. This paper illustrates a more accurate test methodology development to derive the real-world range in electric vehicles with experimental validation and system level analysis. A test matrix is developed considering several variables influencing vehicle range like different routes, drive modes, Regeneration levels, customer drive behavior, time of drive, locations, ambient conditions etc.

This paper describes application of Design of Experiments (DOE) technique and optimization for mass reduction of a Sports utility vehicle (SUV) body in white (BIW). Thickness of the body panels is taken as design variable for the study. The BIW global torsion, bending and front end modes are key indicators of the stiffness and mass of the structure. By considering the global modes the structural strength of the vehicle also gets accounted, since the vehicle is subjected to bending and twisting moments during proving ground test. The DOE is setup in a virtual environment and the results for different configurations are obtained through simulations. The results obtained from the DOE exercise are used to check the sensitivity of the panels. The panels are selected for mass reduction based on the analysis of the results. This final configuration is further evaluated for determining the stiffness and strength of the BIW.

As a car OEM, we continuously strive to set the bar for competitors with every product. Consumer travel experiences are enhanced by increasing passenger cabin silence. There is only one steering system opening in the firewall panel, which is used for allowing intermediate shaft's fitment on the pinion shaft of the steering gear. The steering grommet is the sole component that covers the firewall cut-out without disrupting steering operations, which has a substantial impact on the NVH performance of the vehicle. It is typically used in cars to eliminate engine noise and dust entering to passenger compartment. The part is assembled inside the vehicle where the steering intermediate shaft passing through BIW firewall panel. We use a bearing, plastic bush, or direct rubber interference design in the steering grommet to accommodate the rotational input the driver provides to turn the automobile.

The automobile industry strives to develop high-quality vehicles quickly that fulfill the buyer’s needs and stand out within the competition. Full utilization of simulation and Computer-Aided Engineering (CAE) tools can empower quick assessment of different vehicle concepts and setups without building physical models. Vehicle execution assessment is critical in the vehicle development process, requiring exact vehicle steering system models. The effect of steering system stiffness is vital for vehicle handling, stability, and steering performance studies. The overall steering stiffness is usually not modeled accurately. Usually, torsion bar stiffness alone is considered in the modeling. The modeling of overall steering stiffness along with torsion bar stiffness is studied in this paper. Another major contributing factor to steering performance is steering friction. The steering friction is also often not considered properly.

Accurate ride and handling prediction is an important requirement in today's automobile industry. To achieve the same, it is imperative to have a good estimation of damper model. Conventional methods used for modelling complex vehicle components (like bushings and dampers) are often inadequate to represent behaviour over wide frequency ranges and/or different amplitudes. This is difficult in the part of OEMs to model the physics-based model as the damper’s geometry, material and characteristics property is proprietary to part manufacturer. This is also usually difficult to obtain as a typical data acquisition exercise takes lots of time, cost, and effort. This paper aims to address this problem by predicting the damper force accurately at different velocity/ frequency and amplitude of measured data using Artificial Neural Networks (ANN).

Aerodynamics of on-road vehicles has come to the limelight in the recent years. Better aerodynamic design of vehicle would improve vehicle fuel efficiency with increased acceleration performance. To obtain best aerodynamic body, the series of design modifications and different testing methodologies must be involved in vehicle design and validation phase. Wind tunnel aerodynamic force measurement, road load determination and computational fluid dynamics were the common methods used to evaluate the aerodynamic behavior of the vehicle body. As a novel approach, the present work discusses about the on-road (Real time) testing methodology that is aimed to evaluate the aerodynamic performance of vehicle body using surface pressure mapping. A 64-Channel digital pressure scanner has been utilized in this work for mapping the pressure at different locations of the typical vehicle body.

Manual transmission (MT) is still the most preferred solution for emerging markets due to the lower cost of ownership and maintenance coupled with a higher transmission efficiency. In this regard, continuous improvement of the transmission shift quality is quite essential to meet the growing customer expectations. In the present work, a detailed evaluation of the gear-shift impulse (experienced at the gear-shift knob) is conducted between two different architectures of a manual, high-torque (450 Nm input torque) inline transmission meant for a sports utility vehicle (SUV). The conventional manual inline transmission architecture comprises a common gear pair at the input of the transmission. While this input reduction architecture is the most widely used architecture, having the common gear pair at the output of the transmission is also another option. The synchronizers of the manual transmission need to match the speed of the rotating components just before the gear-shifting event.

This paper focuses on reducing abnormal noise originating from suspension when driving on rough road at the speed of 20 kmph. The test vehicle is a front wheel driven monocoque SUV powered by four cylinder engine. Cabin noise levels are higher between 100 to 800 Hz when driven on rough road at 20 kmph. Vibration levels are measured on front and rear suspension components, front and rear subframe, subframe connections on body to identify the noise source locations. Since the noise levels are dominant only in certain rough patches at very narrow band of time, wavelet analysis is used for identification of frequency at which the problem exist. Based on wavelet analysis, it is identified that the vibration levels are dominant on front lower control arm (LCA). The dynamic stiffness of LCA bushes is reduced by ~ 40% to improve the isolator performance which reduced the noise levels by ~ 9 dB (A) at the problematic frequency band.

Connected vehicle services have come a long way from the early days of telematics, both in terms of breadth of the class of vehicles, and in terms of richness or complexity of the data being handled for Enhancing Customer Experience. The Connectivity Control unit (CCU) is a gateway device for the vehicle to the outside world. While it enables transmission of vehicle data along with the location information. CCU is currently validated in the vehicle to check functionality. It has cost, time drawbacks and prevents effective testing of many scenarios. Bench level validation will not be able to complete functionality validation. There is subset of validation tools or semi-automated solutions are available in the market, but they are not fully functional, and critically cannot perform end to end validation. Automated Test setup for CCU in lab simulating the entire field data of the vehicle with modifiable characteristics.

This paper presents the analysis and experimental validation of c-spring and its stiffness properties in the gear shift synchronizer system. A synchronizer assembly for a transmission comprises of a synchronizer hub carried by a torque delivery shaft and a cone clutch member carried by a gear and a synchronizer blocking ring. The gear shift sleeve is meshing over the teeth of the clutch hub. The c-spring is positioned in the inner circumference of the rim position of the clutch hub and strut keys will be positioned at the slots on the clutch hub, which are usually 120 degree apart. As the sleeve moves while gear shifting, it pushes down the strut keys which compress the C-spring radially inward; this gives the strut load. The strut keys, which are pushed down by the sleeve, will apply force on the c-spring from radial directions. Since the c-spring is in the shape of an arc it is assumed as a curved beam for the analysis.

Plastics are prone to photo oxidative and thermal oxidative degradation under usage conditions due to their chemical nature. From sustainability and cost standpoint, there is an increasing focus on Mold-In-Color (MIC) plastic materials. Simultaneously customer’s expectations on the perceived quality of these MIC parts has been increasing with attractive color and glossy appearance. A study was conducted to analyze the product quality and durability aspects over a prolonged exposure to accelerated weathering condition. Material selected for this study were injection molded specimens of ABS and PC-ABS used in automotive passenger vehicles. Comparative analysis was conducted before and after weathering exposure at defined intervals by using Fourier Transform infra-red spectrometer (FTIR), differential scanning colorimetry (DSC), universal testing machine (UTM), Izod impact tester and microscope to understand the impact on their chemical and mechanical properties.

Manual transmissions are the preferred transmission for drivers who love sporty gear shifts. Manual transmission vehicles are cheaper, very efficient, and offer quick gear shifts. Worldwide manual transmission contributes to 36.15% and in India it contributes overall 80% of today's market share. The customers expect a very smooth gearshift which is a challenge to achieve in all ambient temperatures. In a gear shift event, the synchronizers synchronize the speed of the gears. The force applied at the gear shift knob, generates the cone torque and stops the rotating input shaft for the Neutral (N) to 1 gear shifting. The early morning gear shifts have high gear shift effort. This effort is getting reduced with the increase in temperature. This is due to the drag in the gearbox which is inevitable. This work focuses on improving the very first gear shift event of N to 1 after the engine crank from cold (8°) to hot (80°) condition.

Twist beam is a type of suspension system that is based on an H or C shaped member typically used as a rear suspension system in small and medium sized cars. The front of the H member is connected to the body through rubber bushings and the rear portion carries the stub axle assembly. Suspension systems are usually subjected to multi-axial loads in service viz. vertical, longitudinal and lateral in the descending order of magnitude. Lab tests primarily include the roll durability of the twist beam wherein both the trailing arms are in out of phase and a lateral load test. Other tests involve testing the twist beam at the vehicle level either in multi-channel road simulators or driving the vehicle on the test tracks. This is highly time consuming and requires a full vehicle and longer product development time. Limited information is available in the fatigue life comparison of multi-axial loading vs pure roll or lateral load tests.