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Enriched ventilation and driver assistance systems which plays vital role in human thermal comfort and safety, are now necessities for the whole automotive sector. For faster cabin thermal comfort, air circulation around occupant’s body reveals higher cabin comfort index. In India natural and forced ventilation system is predominantly used in commercial vehicles as an economical solution for achieving interim cabin comfort over air conditioning system. Presently used forced ventilation system consist of electrically driven blower motor to remove stale air around human body which is adding alternator load and thus affects fuel economy. Remarkably, 22% of such auxiliary electrical load is taken by electrical components from engine generated power. In order to enhance cabin thermal comfort and conceivably reduce power usage, an effective air flow control system is need of hour.

In India, around 70 million people travel by public transport buses. With rising air pollution across cities, there is a need to safeguard passengers from inhaling polluted air. Contaminants in such polluted air could be fine to coarse dust (2.5 micron to 100 micron), exhaust gases (oxide of sulphur, nitrogen and carbon), total volatile organic compounds, bacteria and viruses arising out of covid-19 pandemic. Passengers commuting in buses are continuously inhaling air that is re-circulating through the Air Conditioning system (AC) and also comes in contact with multiple co-passengers and touch points. This air potentially carries a high dose of contaminants and inhalation of such air can lead to health issues. Vehicle manufacturers intend to provide clean air inside the vehicle cabin by configuring various Air Purification systems (AP) which reduce air contaminants in the closed space of a cabin.

Commercial electric vehicle air conditioning system keeps occupants comfortable, but at the expense of the energy used from the battery of vehicle. Passengers around the world are increasingly requesting buses with HVAC/AC capabilities. There is a need to optimise current air conditioning systems taking into account packaging, cost, and performance limits due to the rising demand for cooling and heating globally. Major elements contributing to heat ingress are traction motor, front firewall, windshield & side glasses and bus body parts. These elements contribute to the bus’s poor cooling and lack of passenger comfort. This topic refers to the reduction of the heat ingress through usage of different glass technology like IR Cut & solar green glass with different types of coating.

AC system provides the human comfort inside the cabin of a vehicle but at the expense of consumption of energy from the vehicle. On a global perspective for the bus segment, there is an increased demand for cooling in tropical countries. Optimization needs to be done in existing AC systems w.r.t packaging, cost & performance constraints. Major elements contributing to heat ingress are engine hood, front firewall, windshield & side glasses and bus body parts. Due to these reasons inadequate passenger comfort and poor cool down performance of the vehicle is observed. This paper refers to the reduction of heat ingress through different DOE (Design of Experiment) in the area of design & validation for duct & vent layout, insulation, glass & paint technology, evaporator blowers. The new duct design has been evaluated using a CFD tool by varying various parameters to generate desired output. The integrated use of the modifications was found significant improvement at vehicle level.

HVAC system design has an accountability towards acoustic comfort of passengers of a vehicle. Owing to larger cabin volume of a bus, multiple air blowers have to be installed to ensure comfort of passengers. Such multiple blowers produce significant flow induced noise inside the cabin. For commercial success, it becomes essential to predict intensity of such a flow induced noise at very early stages in product development. Conventionally sliding mesh based CFD approach is deployed to predict flow and turbulence noise around each blower. However due to complexity, this method becomes computationally intensive resulting in cost and time inefficiency. Hence it is desirable to innovate around an alternative rapid, reliable prediction method, which ensures quick turnaround of prediction.

Mobile Air Conditioning (MAC) system provides year round thermal comfort to the occupants inside vehicle cabin. In present scenario, 1D CAE simulation tools are widely used for MAC system design, component sizing, component selection and cool down performance prediction. The MAC component sizing and selection mainly depends on cooling load which varies with ambient conditions, occupancy, cabin size, geometry and material properties. Therefore, detailed modeling of vehicle cabin is essential during MAC system digital validation as it helps to predict performance across wide number of contributing factors. There are two different methods available in 1D Simulation for vehicle cabin modeling, viz. ‘simple cabin’ and ‘advance cabin’. With the simple cabin modeling approach, vehicle cabin is modelled as a group of lumped masses, which only enables prediction of average vent and average cabin temperatures. In advance cabin modeling approach, vehicle cabin is modelled more comprehensively.

Virtual Product Development (VPD) with a vision to eliminate prototype testing is the recent trend in the automotive industry. Reducing the total vehicle development period with optimized output has been the major advantage of this new trend, fueled by increasing competition and shorter product life cycle. In this regard, Computer Aided Engineering (CAE) has taken a more significant role than ever in the vehicle development programs. Prediction of road noise in passenger cars is one of the important attributes to NVH (Noise Vibration Harness) Simulations. In the present work, CAE - NVH simulation of road noise is carried out on the finite element model of the vehicle, eliminating the costly and laborious test procedures & the process of awaiting information from various departments. One of the major challenges in these simulations are generating the load inputs for the structure-borne road noise in a cost and time saving method with accuracy.

Fuel economy is becoming one of the key parameter as it does not only account for the profitability of commercial vehicle owner but also has impact on environment. Fuel economy gets affected from several parameters of engine such as Peak firing pressure, reduction in parasitic losses, volumetric efficiency and thermal efficiency. Compression ratio is one of key design criteria which affects most of the above mentioned parameters, which not only improve fuel efficiency but also results in improvement of emission levels. This paper evaluates the optimization of Compression ratio and study its effect on Engine performance. The parameters investigated in this paper include combustion bowl volume in Piston and Cylinder head gasket thickness as these are major contributing factors affecting clearance volume and in turn the compression ratio of engine. Based on the calculation results, an optimum Compression Ratio for the engine is selected.

While designing the exhaust system of passenger car on one hand there is stringent emission regulations, packaging constraints, high NVH performance requirement. On the other hand with lightweight vehicle design there is tremendous pressure on weight reduction of exhaust system while keep the same NVH performance levels. Exhaust system consist of muffler, bellows, pipes and hangers. For muffler design both acoustic (transmission loss, pass-by noise, tail pipe noise etc.) and non-acoustic (backpressure) parameters needs to be considered. In the current paper, methodology for muffler design optimization using 1D acoustic simulation software is presented. The baseline exhaust design consist of two mufflers; main muffler and post muffler. Simulation methodology is developed to optimize main muffler design in order to eliminate post muffler requirement while achieving the same performance of baseline exhaust design.

Emission norms across the world are getting more and more stringent day by day, in pursuit of saving the mother Earth. Automotive industry is quick to respond to this huge challenge. One solution lies in making the vehicles lighter. That's why scope of the lightweight materials is more and more realized and explored during the last decade. One of the front runners in the lightweight material is Carbon Fiber Reinforced Polymer (CFRP). CFRP comes with own challenges in its understanding, designing and engineering. For effective use of the CFRP material, from a design and mass point of view, it has to be optimized in such a way that every section and layup is utilized to its maximum potential. Current paper demonstrates the multi-step optimization approach used in a design and development of car hood. Initial assessment of the hood showed that few attributes were falling short of the requirement targets, and could only be achieved with a mass penalty.

The structure of a vehicle is capable of absorbing a significant amount of heat when exposed to hot climate conditions. 50-70% of this heat penetrates through the glazing and raises both the internal cabin air temperature and the interior trim surface temperature. When driving away, the air conditioning system has to be capable of removing this heat in a timely manner, such that the occupant’s time to comfort will be achieved in an acceptable period [1]. When we reduce the amount of heat absorbed, the discomfort in the cabin can be reduced. A 1D/3D based integrated computational methodology is developed to evaluate the impact of vehicle orientation on cabin climate control system performance and human comfort in this paper. Additionally, effects of glazing material and blinds opening/closing are analyzed to access the occupant thermal comfort during initial and final time AC pull down test.

Designing a cabin tilting system for Light Commercial Vehicles using a single torsion bar becomes challenging considering the operator safety and stringent design weight targets. Performance of a good tilting system entirely depends on cabin mass and location of centre of gravity with respect to (w.r.t) to tilting pivot point. Cabin Mass and COG location are very difficult to estimate while designing a new cabin as it is dependent on the maturation of all other cabin aggregates and also the accessories added by the customer. Incorporation design parameter changes like increasing cab tilting angle and increasing torsion bar length, in the later stages of product development, becomes expensive. The objective of this paper is to come up with an optimum design of a single torsion bar tilting employing “Taguchi optimization” for deciding the optimum levels of control factors, which ensures desired performance (i.e tilting effort vs.