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Turbocharging has become an important method for increasing the power output of diesel engines. A perfectly matched turbocharger can increase the engine efficiency and decrease the BSFC. For turbocharger matching, engine manufacturers are dependent on the turbocharger manufacturers. In this paper, an analytical model is presented which could help engine manufacturers to analyze the performance of turbocharger for different load and ambient condition using compressor and turbine map provided by turbo manufacturers. The analytical model calculates the required pressure at inlet and exhaust manifold for fixed vane turbocharger with waste gate using inputs like BSFC, lambda, volumetric efficiency, turbocharger efficiency and heat loss, that are available with the engine manufacturer.

In an automobile, main function of the steering system is to allow the driver to guide the vehicle on a desired course. Steering system consists of various components & linkages. Using these linkages, the torque from steering wheel is transferred to tyre which results in turning of the vehicle. Over the life of vehicle, these steering components are subjected to various loading conditions. As steering components are safety critical parts in the vehicle, therefore they should not fail while running because it will cause vehicle breakdown. In commercial vehicle segment, vehicle breakdown means delay in freight delivery which results in huge loss to costumer. Therefore, while designing steering components one should consider all the possible loadings condition those are possible. But, it can’t be done through theoretical calculation. Therefore, physical tests have to be carried out to validate design of steering system, which is very costly & time-consuming process.

In today’s automobile industry refined NVH performance is a key feature and of high importance governing occupant comfort and overall quality impression of vehicle. In this paper interior noise and vibration measurement is done on one of the light truck and few dominant low frequency noise booms were observed in operation range. Modal analysis was done for the cabin at virtual as well as experimental level and few modes were found close to these noise booms. Vibrations were measured across the cabin mounts and it was found that the isolation of front mounts is not effective at lower frequencies. Taking this as an input, the mount design was modified to shift the natural frequency and hence improve the isolation behavior at the lowest dominant frequency. This was followed by static and dynamic measurement of the mounts at test rig level to characterize the dynamic performance and stiffness conclusion.

An efficient after treatment technique is driven by the need to maintain strict emission norms for heavy-duty and medium-duty ground vehicles. SCR being an advanced active emission technology system for diesel engine, is one of the most cost-effective and fuel-efficient technologies available for complying with the stringent NOx emission legislations. The design of the SCR system involves catalyst selection, complex controller development like urea dosing strategy and the interaction between engine setup and after treatment system. For this purpose, the SCR model must be computationally efficient to evaluate the complete efficiency along with to take care for the NH3 slip also. The SCR model was prepared with respect to SCR inlet temperature and ratio of NOx and ammonia to study the behavior of NOx conversion efficiency keeping consideration of NH3 slip also required for optimizing the calibration.

BSIV implementation for commercial vehicle in pans India effectively from April 2017. It’s very challenging job for performance and emission engineer to meet engine performance & fuel economy with stringent emission norms for high power and torque density HD diesel engine. In Altitude, lack of air availability & combustion energy passes by mechanical waste gate, lead to lower boost at partial load in waste gate region; which in turn leads to poor engine performance & fuel efficiency and higher turbo speed. To control the turbocharger design speed limit various methodologies adopted like engine derating or optimizing the combustion parameters leads to poor vehicle performance. Combustion parameter optimsation is having limited scope for turbocharger speed control.

At the time of invention of road coaches, the vehicle consisted only of an axle with wheels and a body attached. Smooth roads were built for a better ride comfort however they were not consistent. The road coaches were too bumpy and uncomfortable for the passenger along with the driver who was not able to control the vehicle. That's why the engineers had to shift their attention to the suspension system for a better ride comfort and handling. The technology has advanced with time so as the suspension system. Rubber ended type leaf spring is one of the suspension system types available in the industry. The main function of a suspension in order of importance is as below: 1 Acts as a cushioning device ensuring the comfort of the driver and passengers; 2 Maximizes the contact between the tires and the road surface to provide steering stability with good handling; 3 Protects the vehicle itself and any cargo or luggage from damage and wear.

Ride Comfort forms a core design aspect for suspension and is to be considered as primary requirement for vehicle performance in terms of drivability and uptime of passenger. Maintaining a balance between ride comfort and handling poses a major challenge to finalize the suspension specifications. The objective of this project it to perform ride- comfort analysis for a commercial truck using MATLAB Simulink. First, benchmarking was carried out on a 4x2 commercial truck and the physical parameters were obtained. Further, a mathematical model is developed using MATLAB Simulink R2015a and acceleration- time data is collected. An experimentation was carried out on the truck at speeds of 20 kmph, 30 kmph, 40 kmph and 50 kmph over a single hump to obtain actual acceleration time domain data. The model is then correlated with actual test over a single hump. This is followed by running the vehicle on Class A, B & C road profiles to account for random vibrations.

The engine coolant temperature influences fuel consumption, power, emissions and mechanical load on the components. The optimization of these variables does not permit a fixed temperature value if there are different speed and load states. The optimization requires a temperature range that corresponds to each operating point. A conventional wax thermostat has a wide temperature control range. The start to open and full open temperature values depend on the mechanical properties of the spring and wax material. Hence, there is no control on the coolant temperature band in real time. This paper deals with the performance analysis & optimization of engine cooling system by using electronically controlled coolant thermostat for improving engine thermal efficiency. To integrate this technology with an existing engine, some design modifications have been made in the thermostat housing mounted on the engine cylinder head and radiator inlet hosepipe.

Electric vehicles have a limitation of limited range and long charging time. Energy optimization plays a very crucial role in determining the range of an electric vehicle. The innovative system proposed here gives the opportunity to reduce energy wastage and efficiently direct the electrical energy to improve the driving range of a 9 meter AC electric bus. The high voltage air conditioner unit alone consumes more than 40% of the electrical energy stored in the traction battery which reduces the driving range of the electric bus drastically. The proposed system optimizes the air conditioner utilization to direct cool air only in areas where passengers are present. Buses do not always run on full capacity, when there are less number of people in the bus the system detects the locations of the passengers using sensors and occupant detection algorithm, this enables the controller to identify the areas where cooling has to be focused and where cooling can be reduced or stopped.

Wheel end bearing is one of the critical components of the vehicle as it directly faces the road loads for harsh operating environment. Bearing being a precisely manufactured component and rotating at high speed, utmost care is required while assembling as well as during operation. In operating condition wheel end is directly exposed to outside environment making it prone to entry of contamination. This contamination if not prevented from entering into wheel end through proper sealing it would cause lubricant contamination and consequently bearing failure. Bearing replacement and overall wheel end service is time consuming activity reducing the turn out time of the vehicle. In wheel ends, one side is sealed with the help of seal while the other side is protected by cap and gasket. This cap-gasket interface is very critical from sealing perspective and utmost importance needs to be taken while designing the same.

Nowadays technology is changing day by day and so as the expectation of the customers. Customers relate their vehicle and their reputation. Smoke coming out of vehicle affects badly on the reputation of the customer that is why today’s customer wants smoke free vehicle during transient condition. Low Air Fuel Ratio leads to smoke due to rich combustion mixture. Smoke could be generated due to turbo leg, sudden acceleration, gear changing, cold condition, altitude etc. During sudden acceleration, turbo leg leads to rich mixture which is favourable condition for smoke generation. It is difficult to reduce turbo leg in waste gate type turbocharger while maintaining EGR requirement in EGR based Engine. Smoke can be optimized by controlling fuelling in sudden acceleration or in transient condition. However it might adversely affect on vehicle pick up and could improve fuel economy.

The cabin or cab is an enclosed space where the driver and co-driver are seated. Structural parameters such as modal and stiffness characteristics are of key importance for its durability study and driver’s comfort. The desired strength and stiffness value of the cabin have to be met at the development phase itself. In developing new cabin models numerical simulations are used for estimating vehicle performance to reduce the development cycle. But, the conventional method of modeling the cabin using 2-d elements and performing subsequent iteration steps to arrive at the desired stiffness and strength value will be cumbersome and time consuming. Thus, a methodology of FE modeling of the truck cabin using 1-D elements has been proposed in this paper which will reduce the analysis time of successive iterations. For this purpose an existing proven driver’s cabin is modeled using 1-D elements.

In the current commercial vehicles market, ride-comfort and handling are crucial parameters for the customer and end user. There are various aspects which determine the vehicle behavior. One of aspects is the structural rigidity of the vehicle, which has its own effect on vehicle dynamics. To meet the required stiffness of the main structural component of the vehicle i.e. chassis frame, FEA analysis has to be done in current methodology. The number of iterations have to be done to build an appropriate model with low weight, which can meet the design requirements. At first, conceptual design mock-up unit is to be developed then FEA (CAE) analysis to be done on it. If any design criteria are not met, then this cycle repeats again until it fulfils the required stiffness. Today, the direct stiffness procedure is the basic principle of almost every FEA software package.

Most popular practice for analyzing the Subsystem failures in commercial vehicles is physical testing. These physical tests are carried out by three tests; Endurance testing, Accelerated Endurance Testing and Rig test simulation. All the three methods are costly and repetitive iterations of these tests is not economical. Therefore, in our organization, we established a method in virtual domain in order to reduce the repetitive iterations and also reduction in time consumed per iteration. General practice in our organization for Finite Element Analysis (FEA) calculation was inclusive of Model preparation, Transient analysis using Nastran. The results from the Transient analysis are used for performing fatigue analysis in fatigue software. In this process, Transient analysis and Model preparation are very much time consuming processes. Model preparation cannot be reduced, but to reduce the transient analysis time, we established a method in frequency domain (vibrational fatigue) [1].

Ever-increasing operational cost, reducing profit margins & increase in competition, it is of upmost significance for fleet owners & drivers to opt for a vehicle having maximum uptime. OEM's are under immense pressure to design & develop vehicles/subsystems which are reliable enough to minimize downtime & withstand heavy overloading plus extreme operating conditions especially tippers. Vehicle systems like Wheel end (hub, bearing, and grease) which are designed & packaged according to a very stringent envelop & operate as a closed system facing all the extremities of operating conditions. This undoubtly make them prone to no. of failure modes which are resulting in vehicle unplanned stoppages, so any failure mode related to the same must be taken care with utmost importance. In commercial vehicles the bearing outer cup is in interference fit with the hub. These bearings of wheel hub have to be maintained at the wheel end play of few microns.

The need to develop products faster and to have designs which are first time right have put enormous pressure on the product development timelines, thus making computer aided optimization one of the most important tool in achieving these targets. In this paper, a design of experiments (DOE) study is used, to gain an insight as to, how changes to different parameters of front suspension and steering of a passenger bus affect its kinematic properties and thus to obtain an optimized design in terms of handling parameters such as bump steer, percent ackermann error and lock to lock rotation angle of steering wheel. The conventional hit and trial method is time consuming and monotonous and still is an approximate method, whereas in design of experiments (DOE), a model is repeatedly run through simulations in a single setup, for various combinations of parameter settings.

Passenger vehicles are used as one of the frequently used and versatile mode of transport. Commercial buses cater to short to long distance travel for city as well as highway applications. Thus, passenger ride comfort becomes paramount for the salability of the vehicle. Generally, it is observed that the rear seat experiences the worst ride comfort characteristics due to rear overhang and pitching characteristics of buses. Therefore the objective of this project is to improve the rear seat vibrations of passenger bus by tuning damper characteristics. Shock absorbers, being a low cost and easily interchangeable component is tuned first before optimizing other suspension parameters. The methodology is as follows: first, a 4 degree of freedom mathematical model is created on MATLAB Simulink R2015a environment. Time domain data is obtained by road load data analysis and used as an input for the mathematical model.

Seats are one of the critical component of school bus for children’s comfort & safety. Seat foam thickness, its shape, cushion width & seat height will play a vital role in comfort. Fatigue is the common cause due to uncomfortable seating and it is due to only one type of seat available in school buses to accommodate different height children. (here different height means; schools have children from class nursery to senior secondary). Fatigue will cause impact on children’s health & overall development. The topic was chosen because of increasing concerns in children’s comfort & safety in school buses. In existing design, standard seat with cushion height from bus floor is 450mm. In this case, it’s only suitable for children height of 4.5 feet to 5.5 feet. Ergonomically, it is very difficult to climb on the seat for range of children height from 3 feet to 4feet.

Market driven competition in global trade and urgency for controlling the atmospheric air pollution are the twin forces, which have urged Indian automobile industries to catch up with the international emission norms. Improvement in the fuel efficiency of the vehicles is one way to bind to these stringent norms. It is experimentally proven that almost 40% of the available useful engine power is being consumed to overcome the drag resistance and around 45% to overcome the tire rolling resistance of the vehicle. This as evidence provides a huge scope to investigate the influence of aerodynamic drag and rolling resistances on the fuel consumption of a commercial vehicle. The present work is a numerical study on the influence of aerodynamic drag resistance on the fuel consumption of a commercial passenger bus. The commercial Computational Fluid Dynamics (CFD) tool FLUENT™ is used as a virtual analysis tool to estimate the drag coefficient of the bus.

Chassis frame of a passenger vehicle is one of the primary load bearing components of the vehicle. All the aggregates such as engine, radiator, fuel tank, EATS, air tanks, body and cowl etc. are mounted on to the frame. It should have sufficient stiffness and strength to withstand the static and dynamic loads. At the same time it should also be light in weight as it helps in reducing the fuel consumption and emissions coming out of the vehicle. The main objective of this work is to design a chassis frame of a passenger vehicle of M3 category using Design of Experiments by considering the stiffness and the natural frequency of a similar type of vehicle’s frame (Benchmark) as the target values i.e. the final design of the frame should match the stiffness and natural frequency values of the benchmarked frame with a specified tolerance set as per the general methodology of frame design.