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Vehicle cabin comfort emphasizes a specific image of a brand and its product quality. Low frequency powertrain induced noise and vibration levels are a major contributor affecting comfort inside passenger cabin. Thus, using hydraulic mount is a natural choice. Introduction of lighter body panels coupled with cost effective hydraulic mounts has resulted in some additional noises on rough road surfaces which are challenging to identify during design phase. This paper presents a novel approach to identify two such noises i.e. Cavitation noise and Mount membrane hitting noise based on component level testing which are validated at vehicle experimentally. These noises are encountered at 20~30kmph on undulated road surfaces. Sound quality aspect of such noises is also studied to evaluate the solution effectiveness.

Rapidly changing emission and fuel efficiency regulations are pushing the design optimization boundaries further in the Indian car market which is already a very cost conscious. Fuel economy can be improved by reducing moving parts friction and weight optimization. Driveline or Transmission power losses are major factor in overall efficiency of rotating parts in a vehicle. Transmission efficiency can be improved by using low viscosity oil, reducing oil quantity and reducing churning losses in car transmission. Changes like low viscosity and reduced oil volume give rise to challenges like compromised lubrication and durability of rotating parts. This further leads to extended design cycles for launching new cars with better transmission efficiency and fuel economy into the market. Design cycle time can be reduced by using CFD simulation for oil flow validation in the early design stage.

In today’s Indian automotive industry, vehicles are becoming more complex and require more efforts to develop. Also, new and upcoming regulations demand more trials under varied driving conditions to ensuring robustness of emission control. Combined with expectations of customer to get new products more frequently, requires solutions and methods that can allow more trials with required accuracy to ensure compliance to stricter regulation and delivery a quality product. This translates into more trials in less time during the development life cycle. Recently, to overcome above challenge, there has been focus on simulating the vehicles trials in engine bench environment. ‘Road to Lab to Math’ (RLM) is a methodology to reduce the effort of On-road testing and replace it with laboratory testing and mathematical models. Also, on-road testing of prototype vehicles is expensive as it requires physical parts.

As the automotive market is very dynamic and vehicle manufactures try to reduce the vehicle development cycle time, more focus is being given to CAE simulation technologies to reduce the design cycle time and number of physical tests. CAE engineers are continuously working on improving the accuracy of CAE simulation, such as using flexible body dynamic simulation in place of linear static analysis. Strength calculation under dynamic condition is more accurate as compared to static condition as it gives more clear understanding of stress variation with motion, contacts and mass inertia. Failure has been observed in new development of valve train pivot screw under test conditions. As per linear static analysis, design was judged OK. Normal linear static analysis is a two stage process. In first stage loads are calculated by hand or peak loads are taken from multibody dynamics (MBD) rigid body analysis.

Vehicle Hood being the face of a passenger car poses the challenge to meet the regulatory and aesthetic requirements. Urge to make a saleable product makes aesthetics a primary condition. This eventually makes the role of structure optimization much more important. Pedestrian protection- a recent development in the Indian automotive industry, known for dynamics of cost competitive cars, has posed the challenge to make passenger cars meeting the regulation at minimal cost. The paper demonstrates structure optimization of hood and design of peripheral parts for meeting pedestrian protection performance keeping the focus on low cost of ownership. The paper discusses development of an in-house methodology for meeting Headform compliance of a flagship model of Maruti Suzuki India Ltd., providing detailed analysis of the procedure followed from introduction stage of regulatory requirement in the project to final validation of the engineering intent.

In the present automobile market, customers have put demand for smaller cars with better ride and comfort. For small diesel engine cars, where the comfort is known to be inferior to its gasoline siblings, the effect of engine excitation and road inputs has posed the problem of seat back vibrations. Low frequency vibrations are observed at irregular road inputs, which directly get transferred to the human body through the seat back resulting in fatigue and discomfort. This paper describes the use of testing and CAE in reducing the seat back vibrations. First step of the study includes the frequency response functions (FRF) of the seat frame and road data. The CAE model is validated with the test data and the problem areas are identified. The countermeasure design modifications in the seat frame structure are analyzed using CAE (Normal Mode Analysis). The feasible countermeasure action is road tested and clearly shows a reduction in the vibration levels coming on the seat back.

Vehicles which are sold and put into service in a country have to meet the regulations and standards of that country. Every country has a separate regulation and approval procedure which requires expensive design modifications, additional tests and duplicating approvals. Thus, there is the need to harmonize the different national technical requirements for vehicles and form a unique international regulation. With this rationale, the World Forum for Harmonization of Vehicle Regulations of the United Nations Economic Commission for Europe (UN/ECE/WP29) has brought governments and automobile manufacturers together to work on a new harmonized test cycle and procedure which is to be adopted around the world. This lead to the development of Worldwide Harmonized Light Duty Test Procedures (WLTP) and Cycles (WLTC). The test procedure is divided into 3 cycles, depending on a power to mass ratio of the tested vehicle.

Government’s focus on road safety requirements is resulting in faster adoption of stringent automobile safety regulations in India. In addition, due to changing customer preference, automobile companies are also working to provide safer vehicles in the market. Due to the complexity and high cost of the vehicle safety testing, more focus is given to development of CAE simulation technologies to validate the design for meeting regulatory norms, reducing design cycle time and number of physical tests. Safety requirement in vehicle safety regulations is to minimize the impact transfer to the occupants in case of vehicle crash. During vehicle crash condition, there is possibility that driver head may hit the gear shift lever assembly (GSLA) knob as it falls in the hitting area with respect to driver seat reference point (SRP). There is a regulatory requirement for the maximum acceleration level that is to be experienced by the driver during impact to prevent serious head injury.

With the increasing competition in the automotive industry, customer experience & satisfaction is at the top of every organization's goals. The customers have evolved & NVH refinement has become the parameter for their decision making in buying a car. The major source of rumble noise in a vehicle is the induced vibrations due to combustion forces in an IC engine. These vibrations are then transferred to the vehicle body through engine mounts. Hence engine mounts play a key role in defining the NVH & the ride performance of any vehicle. However, it is infeasible to validate every mount design through the physical test as it will be both costly & time-consuming. But multiple design iterations can be verified by the CAE approach quite effectively. This paper focuses on the novel CAE approach to evaluate the mount vibrations due to engine dynamics. The process involves preparing a FEA model of the complete Powertrain system.

With the increase in customer expectations related to engine performance and vehicle NVH, it has become the need of the hour for automotive industry to continuously use state of-the-art designs. These dynamic concepts require innovative simulation techniques correlated with testing to value engineer the optimal design and further validations. Compact engine room packaging and futuristic aesthetics changes in styling have further magnified these challenges. Packaging air intake system and positioning air intake snorkel are among such challenges that play a critical role for improving engine performance and life. The objective of this paper is to propose an approach for optimizing design and position of air intake snorkel to meet desired intake air temperature, noise targets with no water entry in to engine. Full vehicle computational fluid dynamics (CFD) simulation is performed for predicting air intake temperature, water wading and 1D simulation for suction flow noise.

Nowadays, Road Load Simulators are used by automobile companies to reproduce the accurate and multi axial stresses in test parts to simulate the real loading conditions. The road conditions are simulated in lab by measuring the customer usage data by sensors like Wheel Force transducers, accelerometers, displacement sensors and strain gauges on the vehicle body and suspension parts. The acquired data is simulated in lab condition by generating ‘drive file’ using the response of the above mentioned sensors [2]. For generation of proper drive file, not only good FRF but ensuring stability of inverse FRF is also essential. Stability of the inverse FRF depends upon the simulation channels used. In this paper experimental approach has been applied for the optimization of the simulation channels to be used for simulation of normal Indian passenger car on 4 corners, 6-Axis Road Load Simulator. Time domain tests were performed to identify potential simulation channels.

Automotive Industry is moving towards lightweight vehicle design with more powerful engines. This is increasing a demand for more optimized NVH design. Source-Path-Contributor (SPC) analysis is one of the ways to draw a holistic picture of any NVH problem. In this paper, an NVH problem of low frequency booming noise and steering vibration has been studied in a development vehicle. All three dimensions of SPC paradigm were looked at to propose a feasible and optimized solution at each level of Source, Path and Contributor model. A classical transfer path analysis (TPA) has been done to identify the highest contributing path: transmission mount and suspension arm. Optimization of suspension bush parameter has been carried out using dynamic elastomer testing facility for an improved NVH performance. After identifying source as engine a study of torsional fluctuations due to gas pressure and torsional resonances has been carried out in order to achieve a feasible solution at source.

IC Engine Timing belt is a major noise prone area and it takes time during development to achieve acceptable NVH characteristics. In an existing engine under series production noise problem observed due to excitation of timing belt span by crank timing sprocket tooth. From vehicle perspective noise was heard in vehicle cabin at around idling RPM and a second peak observed around twice the initial RPM. This paper includes a methodology for use of computer based analytical simulation methods to predict timing belt dynamic behavior and NVH characteristics. Along with development of computer based multi body dynamic model for timing belt, validation of simulation model with actual testing was done and after correlation of testing and simulated results countermeasure were finalized based on iterations in multi body simulation model.

The air pollution and global warming has become a major problem to the society. To counter this worldwide emission norms have become more stringent in recent times and shall continue to get further stringent in the next decade. From OEMs perspective with increased complexity, it has become a necessity to use simulation methods along with model based systems approach to deal with system level complexities and reduce model development time and cost to deal with the various regulatory requirements and customer needs. The simulation models must have good correlation with the actual test results and at the same time should be less complex, fast, and integrable with other vehicle function modelling. As the vehicle fuel economy is declared in cold start condition, the fuel economy simulation model of vehicle in cold start condition is required. The present paper describes a methodology to simulate the cold start fuel economy.

Trunk lid (TL) can be opened using hydraulic or pneumatic balancers, coil springs, torsion bars or combination of the above. TL Opening Mechanism specific to Trunk Lid Torsion Bar (TLTB) is being discussed in the paper. After de-latching, TL should open smoothly and stop at such a height that it is visible from driver seat. The system consists of a four bar linkage mechanism, in which the fixed link is formed by BIW Bracket. Connecting link, TL Hinge Arm and Torsion bar arm form the other three links. Hinge has its one end attached to TL and the other end to BIW bracket. Torsion bar arm transfers torque to TL hinge through the connecting link. Major challenges in designing TLTB mechanism are part tolerances, C.G position and Weight variations in individual parts, Torsion bar Raw Material variation, uncertain friction in the system etc.

As we transition towards Internet of Things (IoT) - humans are connected to each other & outside world through the smartphone. Customers tend to use smartphones for varied purposes ranging from communication to entertainment. However, the concern of distraction exists due to poor visibility & accessibility of the phone’s screen in driving condition. One of the repercussion of being connected to smartphone particularly in driving condition includes higher number of road accidents due to distraction. This paper explains one of the key initiatives taken by Maruti Suzuki India Limited to address the same.

Automotive industry today faces the unprecedented challenges both in terms of adapting to changing customer demands in terms of vehicle aesthetics, features or performance as well as meeting the mandatory regulatory requirements, which are being regularly upgraded and becoming stringent day by day. Vehicle hood, being part of vehicle front fascia, needs to fulfill the requirement of vehicle aesthetics as its primary condition. At the same time, every automobile manufacturer has a lineup of older platforms, which are in production and needs to comply with upcoming stricter safety norms, having a structure in under hood area designed as per older philosophy, which further reduces the space available for energy absorption. This makes the structure optimization in vehicle hood area much more challenging. Pedestrian protection - an upcoming regulation in India, has seen some major development in recent times.

Infotainment has always been an important aspect of life which has made its way to car design. The cars today are much more advanced compared to their predecessors. The in-vehicle Infotainment advancements have followed the consumer electronics market in terms of technologies such as Touchscreen; App based Navigation, Voice Assistant and other multimedia services. This trend is going to expand further as smartphones have revolutionized the Infotainment domain with awareness and accessibility to customers. The Infotainment system in the cars are expected to be connected not only to the cloud but various vehicle controllers to display host of information & controls at customer`s fingertips. To design a system that supports connectivity to both cloud and vehicle is challenging in terms of cost and design for the OEMs. With focus on Indian market condition and global trends, this paper analyzes the customer expectation for Connected Infotainment system.

Gear noise and vibration in automobile transmissions is a phenomenon of great concern. Noise generated at the gearbox, due to gear meshing, also known as gear whine, gets transferred from the engine cabin to the passenger cabin via various transfer paths and is perceived as air borne noise to the passengers in the vehicle. This noise due to its tonal nature can be very uncomfortable to the passengers. Optimizing micro-geometry of a gear pair can help in improving the stress distribution on tooth flank and reducing the sound level of the tonal noise generated during the running of the gearbox when that gear pair is engaged. This technical paper contains the study of variation in noise level in passenger cabin and contact on tooth flank with change in micro-geometry parameters (involute slope and lead slope) of a particular gear pair. Further scope of study has been discussed at the end of the paper.

During vehicle development, numerous test are done to ensure safety & durability of the vehicle. One such test prescribed by regulation (IS 12009:1995) is side door intrusion test (SDIT). This test evaluates strength requirement of a side door of passenger cars to minimize the safety hazards caused by intrusion into passenger compartment in a side impact accident viz., initial, intermediate and peak crush resistance. In current scenario the passenger car manufacturers are striving hard on cost reduction by reducing the development cost. Thus, to predict the exact vehicle performance before its prototype stage is vital. This can be achieved by evaluating performance by the help of Computer aided engineering (CAE) During the SDIT, the load is applied to the outer surface of the door in an inward direction. This inward force applied by loading device is resisted by the door assembly, while door is pivoted at door latch and hinge.