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Gearbox power transfer efficiency is a major factor in overall powertrain efficiency of a passenger vehicle. With rapidly changing emission and fuel efficiency regulations, there is a push to increase the gearbox efficiency to improve the overall fuel economy of the vehicle. In case of an existing gearbox, efficiency can be improved by using the low viscosity lubrication oil. Despite a benefit in increasing the gearbox efficiency, lowering down the viscosity of lubrication oil gives rise to few challenges with respect to its performance. One of these challenges is breather performance which defines that transmission oil should not come out of breather pipe in some pre-defined conditions during gearbox operation. As this validation is being carried out on proto parts when the complete system is ready, failure to satisfy the defined criteria for breather performance can lead to multiple trials.

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.

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.

In a Passive suspension, a shock absorber generates damping force by pressurizing the oil flow between chambers. Typically, vehicle responds with suspension deflection, which significantly depends on damping forces and suspension velocity. Tuning dampers for various roads and steering input is an iterative balancing process. In any setting, damping force w.r.t velocity is tuned for optimum ride and handling performance. Practically, to achieve a balance between the two is a tedious task as the choices & arrangements of inner parts like piston, port, valve etc., which defines the forces set up [soft / hard] are almost infinite. The objective of this paper is to measure, objectify and evaluate the performance of two such optimum setting in various ride and handling events. A passenger car set up with an optimum soft & hard suspension damping force is studied for various ride and handling sub-attributes and their conflicts are examined in detail from a performance point of view:

Valve train system is one major contributor to engine overall friction loss and is approximately 30% of total engine friction at lower speed and approximately 20 % at higher engine speed. Valve spring loads (preload and working) are proportional to friction loss of valve train. To optimizing the valve spring design main requirement is valve train perform it function safely at maximum engine cutoff RPM with minimum preload and working load. Robustness and frictional power loss are contradicting requirement, robustness demand high stiffness spring for better valve jump and bounce performance with dynamic safe valve spring design, on the other hand low frictional power loss demand for use of low stiffness spring. To optimize the valve spring stiffness for meeting both the requirement we need accurate prediction of valve spring in design stage and good correlation with testing data to reduce the number of iterations.

With more stringent emission norm coming in future, add more pressure on IC engine to improve fuel efficiency for survival in next few decades. In gasoline SI (spark ignition) engine, valve events have major influence on fuel economy, performance and exhaust emissions. Optimization of valve event demands for extensive simulation and testing to achieve balance between conflicting requirement of low end torque, maximum power output, part load fuel consumption and emission performance. Balance between these requirements will become more critical when designing low cost valve train without VVT (Variable valve timing) to reduce overall cost of engine. Higher CR (Compression ratio) is an important low cost measure to achieve higher thermal efficiency but creates issue of knocking thereby limiting low speed high load performance. The effective CR reduction by means of late intake valve closing (LIVC) is one way to achieve higher expansion ratio while keeping high geometric CR.

Shielding vehicle underbody or engine room components from exhaust heat is becoming a difficult task with increasing packaging constraints, which lead to the proximity of components with high temperatures of the exhaust systems. Heat insulators are provided to protect various components from exhaust system parts. Generally the requirement of heat insulators are fixed on the basis of benchmarked temperatures measured on vehicles with similar layout, during the initial phase of vehicle design. Also various CFD techniques are available to predict the surface temperatures on components in order to determine the necessity of a heat insulator. The aforementioned techniques use radiation and convection heat transfer effects on a complete vehicle model and the overall process generally takes considerable time to provide the results. This paper deals with a theoretical approach to predict the temperatures on nearby components due to exhaust system heat.

Exhaust system of an automobile is primarily employed in automobile to purify exhaust gases and reduce noise due to combustion. However, a side-effect of the above function is the increase in backpressure. As specified in various literatures, an increase in backpressure can lead to a deterioration on engine performance (Power & torque). Benefit of backpressure reduction can be further taken in terms improving the power & torque of engine or improving the fuel economy. With growing concerns related to global warming and CO2 emissions, reducing exhaust back pressure is one of the promising areas in engine design in order to improve the fuel economy of the automobile and achieving carbon neutrality targets. However, reducing the back pressure generally tends to deteriorate the noise attenuation performance of the Exhaust system.

A typical wheel development process involves designing a wheel based on a defined set of criteria and parameters followed by verification on CAE. The virtual testing is followed by bench level and vehicle level testing post which the design is finalized for the wheel. This paper aims to establish the learning which was accomplished for one such development process. The entire wheel development process had to be analyzed from scratch to arrive at a countermeasure for the problem. This paper will not only establish the detailed analysis employed to determine the countermeasure but also highlight its significance for the future development proposals. The paper first establishes the failure which is followed by the detailed analysis to determine the type of failure, impact levels and the basic underlying conditions. This leads to a systematic approach of verification which encompasses the manufacturing process as well as the test methodology.

In view of global concern for greenhouse gas emissions, need for greener and efficient Engines is increasing. Hence is it imperative that Internal Combustion Engines are improved in terms of efficiency to reduce Greenhouse gas emissions and meet CAFE targets. The cooling system of an ICE plays a major role in a vehicle performance. In this system, the radiator, thermostat, and cooling fan are the main components. Conventional cooling system uses Wax-type thermostat which is activated at specified coolant temperature and maintain same coolant temperature in fully warmed up condition at all engine operating points. Operative temperature selection in Wax-type is trade-off between engine friction & thermal efficiency at lower loads & knocking at higher loads. An electronic thermostat is a good alternative to maintain optimum temperature as per operating point requirement since optimum temperature at different operating points can be different.

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.

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.

Fabrics play a vital role in defining the overall aesthetics of automotive interiors, primarily with fabric cleanliness. In this respect, the cleanliness of the fabric also becomes equally important. The fabric interior in a car is very prone to staining due to the spilling of water or any liquid substance over it. In order to protect and enhance the life of the fabric, various chemical treatments are suggested as fabric finishes. There are different chemical bases available for the same. Fluorocarbon base is the most effective treatment and is the focus of this study. This chemical treatment lowers the surface energy of the fabric by increasing the hydrophobicity of fabric. Hence, the liquid roll over the surface in the form of droplets by creating higher contact angle over the fiber surface. This study focuses on the effect of chemical treatment on the automotive fabric’s parameters, especially light color fabric.

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.

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.

With the development of automobile industry, customer awareness about NVH (Noise, Vibration and Harshness) levels in passenger vehicles and demands for improving the riding comfort has increased. This has prompted automobile OEMs to address these parameters in design stage by investing resources in NVH research and development for all components. Better NVH of Radiator Fan Module (RFM) is one of the parameters which contributes to cabin comfort. The basic objective of RFM is to meet engine heat rejection requirements with optimized heat transfer and air flow while maintaining NVH within acceptable levels. The rotating fan (generally driven by an electric motor), if not balanced properly, can be a major source of vibration in the RFM. The vibration generated thus, can be felt by customer through the vehicle body.

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.

With increase in product diversity in passenger car market, the need for NVH comfort has gained very strong foothold in every segment. This needs in depth analysis for limiting the noise at part level. Radiator Fan Module is one of such part which contributes to Cabin comfort in major way. In this paper, author is focusing on designing of RFM (Radiator Fan Module) in order to have low noise. Primary objective of RFM is to meet Heat rejection requirement with optimized air flow. Radiator Fan is primarily responsible for meeting air flow requirement within specified noise limit. For flow inducing components like Radiator Fan, there is always a trade-off between the functional requirement and the noise from various sources (Electrical / Mechanical / Flow). Design of Fan blades and Motor Support ribs in RFM is critical to improve Flow noise, i.e. Air cutting noise.

Powertrain Control development has gone through many changes in terms of process, tools and practice at all OEM's across the geography. This is mainly driven by increased number of powertrain components for control, shorter development schedules, cost control, and the need to realize the potential of electronic control to increase the performance, efficiency, safety and comfort. With the significant advancement in Powertrain Controls and additions of electronic functions, it has become imperative to automate the controller development process in the V-cycle to reduce the time and make the process more efficient while detecting any logic failures upfront at the early stage of the development cycle. Traditional practices and tools of defining the controls cannot meet new requirements. Model Based Design (MBD) approach is a promising solution to meet the critical needs of powertrain control engineering to define the control logic and validate.

With the advent of stricter regulation for tail pipe emission and urge to reduce the carbon foot prints, the engine hardware has undergone through evolutionary changes over the years i.e., boosting, low viscosity engine oil, high pressure fuel injection, cooled EGR, friction reduction, downsizing etc. These technological changes have led to the challenge of increase in radiated noise level from the engine (source) due to increased number of auxiliary drives on engine i.e., Turbo charger, HP fuel pump along with faster combustion & harsher operating conditions. The fuel system is one such system which has become most intricate with operating pressure going above 2000bar in the fuel rail and capability of up to 10 fuel injection per combustion. These changes in hardware could result in abnormal noise generation during specific operating conditions which may result in customer annoyance inside vehicle cabin.