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Selective Catalytic Reduction has established itself to significantly reduce NOx emissions from diesel engines. Typically, in this technology, aqueous urea solution is injected into hot exhaust stream which chemically decomposes to form ammonia and then reacts with NOx to form safe byproducts as H2O and N2 over the catalyst surface. However, incomplete thermal decomposition of urea not only reduces the NOx conversion efficiency and increases the ammonia slip, but also leads to the formation of solid crystals that adversely affect the performance of the system by increasing the back pressure and lowering the overall fuel economy. The present study discusses about the main reasons that lead to crystal formation in a vanadium based SCR system on a six cylinder 5.6l diesel engine and also design considerations of decomposition tube that affect the formation of crystals and ways to mitigate them.

In an electric vehicle, engine is replaced with battery and transmission is replaced with traction motor. Thermal management of electric battery and motor became a necessary evaluation step in the design and development process of electric vehicles. The temperature of the traction motor coolant is required to be maintained below 600C to ensure proper functioning of the system. Coolant takes away heat from traction motor, motor controller along with an on-board charger in battery charging and discharging conditions. In this paper the cooling unit selection for the total required heat rejection from all three components is analytically calculated and thermal management methodology of liquid-cooled Electric Motor is being studied and documented with the help of numerical simulation. The results are further validated with test results in Electric bus for city application.

In the current landscape of commercial vehicle industry, fuel economy is one of the major parameter for fleet owner’s profitability as well as greenhouse gasses emission. Less fuel efficiency results in more fuel consumption; use of conventional fuel in engines also makes environment polluted. The rapid growth in fuel prices has led to the demand for technologies that can improve the fuel efficiency of the vehicle. Phase change material (PCMs) for Thermal energy storage system (TES) is one of the specific technologies that not only can conserve energy to a large extent but also can reduce emission as well as the dependency on convention fuel. There is a great variety of PCMs that can be used for the extensive range of temperatures, making them attractive in a number of applications in automobiles.

In the modern era of commercial vehicle industry, passenger and driver comfort is one of the major parameters that improves vehicle running time which leads to fleet owner’s profitability. Air conditioning system is one such system whose primary function is to provide the required cooling inside the cabin in hot weather conditions. An Air-conditioned truck cabin creates a comfortable environment for the driver which increases his efficiency and reduces fatigue. An AC compressor consumes power directly from the engine affecting fuel economy and vehicle performance. With ever increasing demand for energy efficient systems and thermal comfort in automobiles, AC systems should be able to deliver the required cooling performance with minimum power consumption. Therefore, reducing AC power consumption in vehicles is one of the key challenges faced by climate control engineers.

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.

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.

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.

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.

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.

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.

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.

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.