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In cold climatic regions (25°C below zero) thermal comfort inside vehicle cabin plays a vital role for safety of driver and crew members. This comfortable and safe environment can be achieved either by utilizing available heat of engine coolant in conjunction with optimized in cab air circulation or by deploying more costly options such as auxiliary heaters, e.g., Fuel Fired, Positive Temperature Coefficient heaters. The typical vehicle cabin heating system effectiveness depends on optimized warm/hot air discharge through instrument panel and foot vents, air directivity to occupant's chest and foot zones and overall air flow distribution inside the vehicle cabin. On engine side it depends on engine coolant warm up and flow rate, coolant pipe routing, coolant leakage through engine thermostat and heater core construction and capacity.

With the current state of ever rising fuel prices and unavailability of affordable alternate technologies, significant research and development efforts have been invested in recent times towards improving fuel efficiency of vehicles powered with conventional internal combustion engines. To achieve this, a varied approach has been adopted by researchers to cover the entire energy chain including fuel quality, combustion quality, power generation efficiency, down-sizing, power consumption efficiency, etc. Apart from energy generation, distribution and consumption, another domain that has been subjected to significant scrutiny is energy recuperation or recovery. A moving vehicle and a running engine provide a number of opportunities for useful back-recovery and storage of energy. The most significant sources for recuperation are the kinetic energy of the moving vehicle or running engine and to a lesser extent the thermal energy from medium such as exhaust gas.

The vehicle Heating, Ventilation and Air conditioning (HVAC) system is designed to meet both the safety and thermal comfort requirements of the passengers inside the cabin. The thermal comfort requirement, however, is highly subjective and is usually met objectively by carrying out time dependent mapping of parameters like the velocity and temperature at various in-cabin locations. These target parameters are simulated for the vehicle interior for a case of hot soaking and its subsequent cool-down to test the efficacy of the AC system. Typically, AC performance is judged by air temperature at passenger locations, thermal comfort estimation along with time to reach comfortable condition for human. Simulating long transient vehicle cabin for thermal comfort evaluation is computationally expensive and involves complex cabin material modelling.

The use of Wheel Force Transducers (WFTs) to acquire data for laboratory simulation is becoming standard industry practice. However, in test rigs where we have only the suspension module and not the complete vehicle, does the reproduction of the orthogonal forces and moments at the wheel centre guarantee an accurate replication of the fatigue damage in the suspension components? The objective of this paper is to review the simulation methodology for a highly non-linear suspension in a 3 DOF (degree-of-freedom) suspension test rig in which the simulation was carried out using only the three orthogonal loads and vertical displacement. The damage at critical locations in the suspension is compared with that on the road and an assessment of the simulation using the WFT is made based on a comparison of the damage on the road vs. the rig.

EU directive 2005/64/EC on type approval of motor vehicles with respect to their Reusability, Recyclability and Recoverability ( RRR ) requires vehicle manufacturers to put in place the necessary arrangements and procedures for Parts, Materials and Weight (PMW ) data collection from full chain of supply. This is required to perform the calculations of recyclability rate and recoverability rate in line with ISO 22628. Commonly practiced data collection methodologies included spreadsheet and use of internationally available IT support system for collection of material data. Data complexity and prohibitive cost for using Internationally available IT Support systems like IMDS (International Material Data System) has led to the in-house development of IT enabled Solution customizing Siemens PLM software product (Team centre Enterprise) and SAP (SRM suite).

Integrating safety features may lead to changes in vehicle interior component designs. Considering this complexity, design guidelines have to take care of aspects which may help in package feasibility studies that consider systems performance requirements. Occupant restraints systems for protection in side crashes generally comprise of Side Airbag (SAB) and Curtain Airbag (IC). These components have to be integrated considering design and styling aspects of interior trims, seat contours and body structure for performance efficient package definition. In side crashes, occupant injury risk increases due to hard contact with intruding structure. This risk could be minimized by cushioning the occupant contact through provision of SAB and Inflatable IC. This paper explains the methodology for deciding the package definitions using Knowlwdge Based Engineering (KBE) tools.

New noise regulations, with reduced noise limits, have been proposed by UN-ECE. A new method which aims at representing urban driving of the vehicles more closely on roads is proposed and is considerably different from the existing one (IS 3028:1998). It is more complex; we also found that some of the low powered vehicles can not be tested as per this method. The paper proposes ways of improvement in the test method. The new noise reduction policy options will have a considerable impact on compliance of many categories of vehicles. Technological challenges, before the manufacturers, to meet all performance needs of the vehicle along with the cost of development will be critical to meet the new noise limits in the proposed time frame.

Regenerative braking has become one of the major features for a hybrid vehicle as it converts brake energy into electrical energy storable into battery and leads to an increase in overall fuel efficiency of the vehicle. Traditional regenerative braking systems are designed such that the mechanical braking force from the friction brakes is varied in order to get maximum electric braking. This is the optimum method; however, such a system calls from electronics (Anti-lock Braking System) for regulation of mechanical braking leading to an increased cost. In this paper, the authors present a new strategy for implementing a regenerative brake strategy without changing the mechanical brake system of a conventional vehicle converted to a hybrid vehicle. The electric motor that serves as the traction motor or the Integrated Starter Generator (ISG) system, is used for regenerative braking also. There is no change in the other vehicle specifications as compared to the conventional vehicle.

Improvised Explosive Devices (IEDs) and Anti-Tank (AT) mines are a significant threat for military vehicles and their occupants. These explosive devices are designed for the destruction and damage of armored and other vehicles, by using them in battle fields on routes of army vehicles. The blast event results in effects like shockwave, fragments, fire, gases, blast overpressure as well as the vertical impulse load. A blast event affects occupants inside the vehicle in the form of various types of injuries (lower leg, spinal, chest, head etc) and trauma. The Lower leg is the foremost injured body region in a blast event. The term lower leg is used to designate the tibia, fibula and the foot/ankle complex in this paper. Detonations occurring under a vehicle produce high velocity floorboard flutter/deformation and transmit axial loads to lower leg and create injuries.

1 With increasing fuel price, the power train size is on a downward trend. For Fuel Economy maximization, the engine capacity and reduction ratios are getting reduced. So gradability of a vehicle is becoming a trade off factor for the power train size finalization in a car. At the same time OEMs are working hard to maintain profitability by reducing development and operational cost and time. In this complexly competitive scenario in automobile manufacturing, simulation is gaining an upper hand over actual testing as simulation consumes lesser time and resource as compared to actual testing. This paper is aimed at developing a simulation technique for restart or stop and start gradability which is a very critical parameter for finalization of engine torque characteristics and power train configuration. The simulation is done on AVL-CRUISE software.

Micro Hybrid Systems are a premier approach for improving fuel efficiency and reducing emissions, by improving the efficiency of electrical energy generation, storage, distribution and consumption, yet with lower costs associated with development and implementation. However, significant efforts are required while implementing micro hybrid systems, arising out of components like Intelligent Battery Sensor (IBS). IBS provides battery measurements and battery status, and in addition mission critical diagnostic data on a communication line to micro hybrid controller. However, this set of data from IBS is not available instantly after its initialization, as it enters into a lengthy learning phase, where it learns the battery parameters, before it gives the required data on the communication line. This learning period spans from 3 to 8 hours, until the IBS is fully functional and is capable of supporting the system functionalities.

Engine Stop/Start System (ESS) promises to reduce greenhouse emissions and improve fuel economy of vehicles. Previous work of the Authors was concentrated on bridging the gap of improvement in fuel economy promised by ESS under standard laboratory conditions and actual driving conditions. Findings from the practical studies lead to a conclusion that ESS is not so popular among the customers, due to the complexities of the system operation and poor integration of the system design with the driver behavior. In addition, due to various functional safety requirements, and traffic conditions, actual benefits of ESS are reduced. A modified control algorithm was proposed and proven for the local driving conditions in India. The ways in which a given driver behaves on the controls of the vehicles like Clutch and Brake Pedals, Gear Shift Lever were not uniform across the demography of study and varied significantly.

Spot welding is the primary joining method used in automobiles. Spot-weld plays a major role to maintain vehicle structural integrity during impact tests. Robust spot weld failure definitions is critical for accurate predictions of structural performance in safety simulations. Spot welds have a complex metallurgical structure, mainly consisting of fusion and heat affected zones. For accurate material property definitions in simulation models, huge number of inputs from test data is required. Multiple tests, using different spot weld joinery configurations, have to be conducted. In order to accurately represent the spot-weld behavior in CAE, detailed modeling is required using fine mesh. The current challenge in spot-weld failure assessment is developing a methodology having a better trade-off between prediction accuracy, testing efforts and computation time. In view of the above, cohesive zone models have been found to be very effective and accurate.

The automotive industry is heading in the direction of signing off the exhaust system durability based on computer simulation rather than rig simulation and physical vehicle testing. This is due to the cost, time and availability of prototype vehicles and test track. Use of Finite Element Method (FEM) enables to assure the structural integrity of the exhaust system and also contribute to better understanding of the system behavior in the various operating conditions and evaluation of structural strength. This paper deals with dynamic analysis of a modular automotive exhaust system where it is directly mounted on power train pack. Selection of dynamic loads, processing of the test data, and effect of assembly loads along with material property variation due to temperature are explained. It also includes validation of the CAE model, prediction of probable failure locations and improving the design based on analysis outcome.

Authors were challenged with a task of developing a full vehicle simulation model, with a target to simulate the electrical system performance and perform digital tests like Battery Charge Balance, in addition to the fuel efficiency estimation. A vehicle is a complicated problem or domain to model, due to the complexities of subsystems. Even more difficult task is to have a control algorithm which controls the vehicle model with the required control signals to follow the test specification. Particularly, simulating the control of a vehicle with a manual transmission is complicated due to many associated control signals (Throttle, Brake and Clutch) and interruptions like gear changes. In this paper, the development of a full vehicle model aimed at the assessment of electrical system performance of the vehicle is discussed in brief.

Brake noise is one of the common complaints and an irritant not just for the vehicle occupants but equally for the passers-by. Brake noise is actually vibration that is occurring at a frequency that is audible to the human ear. This occurrence of brake noise like brake squeal (>1 kHz) and groan (<1 kHz) is often very intense and can lead to vehicle complaints. During a brake noise event, vehicle basic structure and suspension system components are excited due to brake system vibration and result in a resonance that is perceived in the form of a noise. Proposed work discusses an experimental study that is carried out on a vehicle for addressing concern regarding disc brake squeal and groan noise. Based on the preliminary inputs, vehicle level study was carried out in order to simulate the problem and objectively capture its severity.

This paper focuses on factors that enhance energy efficiency of air conditioning system on mid-sized, standard and premium buses with engine power from 125 to 280 HP. It covers aspects like light weighting of roof air conditioning system, usage of optimized ducting system with minimal resistance to blowers, deployment of rotary scroll compressor with fast idle control in place of reciprocating piston compressor. The scope of this paper covers AC compressors driven by main engine of vehicle/ bus, study related to auxiliary/donkey engine driven AC compressor is not considered. Context- In order to enhance fuel efficiency in buses an energy efficient air conditioning system should be deployed. This will lead to reduced parasitic load on the engine and translate into direct fuel saving.

Better ride and comfort, enhanced safety, reliability and durability, lower running cost as well as cost of ownership continue to be challenges for automotive OEMs. Higher fuel efficiency is considered as USP not only for lower running cost but also is hygiene factor from sustainability point of view. This has necessitated the need for Augmenting Light weighting horizon in automotive OEMs. Augmenting this leads to invention of innovative materials and processes for emerging cost competitive market. This paper focuses on technology efforts towards augmenting light weighting Horizon in Automotive. Light weighting concepts being explored by OEMs with the help of automotive component manufacturers from Powertrain - Engines & Transmission, Chassis and Suspension are discussed.

The objective of the work presented in this paper is to provide an overall CFD evaluation and optimization study of cabin climate control of air-conditioned (AC) city buses. Providing passengers with a comfortable experience is one of the focal point of any bus manufacturer. However, detailed evaluation through testing alone is difficult and not possible during vehicle development. With increasing travel needs and continuous focus on improving passenger experience, CFD supplemented by testing plays an important role in assessing the cabin comfort. The focus of the study is to evaluate the effect of size, shape and number of free-flow and overhead vents on flow distribution inside the cabin. Numerical simulations were carried out using a commercially available CFD code, Fluent®. Realizable k - ε RANS turbulence model was used to model turbulence. Airflow results from numerical simulation were compared with the testing results to evaluate the reliability.

Shock tube is used to simulate blast loading conditions on materials for studying the failure behavior of different materials under blast pressures on smaller scale. This paper describes CAE method developed for simulating shock tube experiment in LS-DYNA3D environment. The objective of shock tube simulation is to characterize material failure parameters so as to predict risk of material failure in full vehicle blast simulations while developing vehicle for blast protection applications. The paper describes modeling of shock wave and its interaction with test specimen in shock tube environment. Arbitrary Lagrangian-Eulerian (ALE) techniques are applied to simulate shock tube experiment in LS-DYNA3D and simulation predictions are compared with experimental test data. CAE correlation studies were carried out with respect to incident and reflected pressures in shock tube, deformation and plastic strains on test specimen, shock wave velocity etc.