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Ride is considered to be one of the crucial criterion for evaluating the performance of a vehicle. Automobile industry is striving for improvement in designs to provide superior passenger comfort in Commercial vehicles segment. In Industry, Quarter-car model has been used for years to study the vehicle’s ride dynamics. But due to lower DOF involved in quarter car, the output accuracy is somewhat compromised. This paper aims in development of a 7 DOF full-car Model to perform the ride- comfort analysis for Light Duty 4*2 Commercial Bus using MATLAB Simulink which can be used to tune the suspension design to meet the required ride-comfort criteria. Firstly, experimental data and Physical Parameters are collected by performing Practical Test on commercial Bus on different road profiles. Secondly, a Full Car Mathematical Model with 7 DOF has been developed for a bus using MATLAB Simulink R2018a.

With the improvement of standard of living, air conditioning has widely been applied in buses. However, in air conditioning buses air distribution is still needs to be improved, One of the main reasons for this sub-quality comfort is two air flow louvers arrangement for 3x2 layout air conditioner buses. Air conditioning buses hatrack louvers are an integral part in providing comfort to passengers. General trend of the numbers of louvers provided to passengers is two louvers for three seats. Disadvantage of having conventional two louvers is that, there is always one passenger left with no option of directing air towards that person. This lead to an opportunity to design three louvers type hatrack instated of conventional two louvers hatrack, for 3x2 seating layout of buses. This way all three passengers can control the louvers for their own comfort and mass of air flow is sufficient for third passenger as well.

This paper focuses on partial encapsulation technique for reducing air-borne noise from the rocker cover of a commercial vehicle diesel engine. Due to increasing awareness, customers demand for improvised NVH (Noise Vibration and Harshness) performance in modern day vehicles. Better NVH performance implies better comfort for passengers as well as vehicle operator. This further increases the driver up time due to reduced driver fatigue. In order to improve NVH performance of existing vehicle and observe different noise and vibration zones, detailed noise and vibration mapping was carried out on one of our vehicle platform. It is observed that engine noise is one of the major contributors for interior noise, apart from road inputs etc.

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.

In order to stand apart from the competition, there is an ever growing demand in Indian commercial vehicle segments to reach higher fuel economy while achieving the emission goals set by the BS-VI norms. With emissions standard set by BS-VI, novel techniques to improve fuel efficiency have to be considered that have least impact with respect to NOx and soot emissions. The optimization of exhaust and intake valve lifts with respect to engine speed, technology commonly known as Variable Valve Lift and Timing (VVT/VVL), has been implemented in many passenger vehicles propelled by gasoline engine. The aim of this work is do initial assessment of utilizing the VVL method on a LMD commercial vehicle diesel engine. A 3.8 litre BS-VI turbocharged EGR engine is used for this study. Valve lift and timing optimization for better fuel efficiency at rated power engine speed is carried out by using one-dimensional thermodynamic simulation software AVL BOOST.

Overall cycle time and prototype testing are significantly decreased by assessment of cooling module performance in the design stage itself. Hence, Front End Cooling and Thermal Management are essential components of the vehicle design process. Performance of the cooling module depends upon a variety of factors like frontal opening, air flow, under-hood sub-systems, module positioning, front grill design, fan operation. Effects of design modifications on the engine cooling performance are quantified by utilizing computational fluid dynamics (CFD) tool FluentTM. Vehicle frontal configuration is captured in the FE model considering cabin, cargo and underbody components. Heat Exchanger module is modelled as a porous medium to simulate the fluid flow. Performance data for the Heat Exchanger module is generated using the 1D KuliTM software. In this paper, CFD simulation of Front End Cooling is performed for maximum torque and maximum power operating conditions.

Virtual validation of automobile components poses a huge challenge and needs continuous process improvements. One of such challenge in FE modelling of welds and understanding its behavior with respect to physical behavior. With the ongoing development of BSVI line of products in commercial vehicle industry, the virtual validation needs to be accurate and close to the physical behavior of the components. The learning and challenges faced during the previous development is implemented in the current study for weld simulation and correlation activity. The brackets welded to the power train components is taken as a challenge in the present work. Initially weld model was depicted in the CAD and was analyzed in CAE by providing proper FE connection. This practice had lot of flaws, approximations due to perpendicularity and flatness concerns in the models leading to consuming a lot of time in model preparation.

The existing head cover is having external oil and blow by separation unit, which is not only costlier but also complex and leads to increase in overall height of engine which was difficult to integrate in new variants of vehicles. A new head cover has been designed with internal baffle type oil and blow by separation system to ensure efficient separation and proper packaging of the system in new variants. The new system has been finalized after 26 DOE’s of different wire mesh sizes and different baffle plate size and positions. The final system has two bowl shaped separation unit with wire mesh, two cup type oil separation passages and one baffle plate for separating blow by. The system works on condensation and gravity method. The blow by is guided through a well-defined passage integrated in aluminum cylinder head cover itself. The passage angle is maintained to ensure minimum oil flow with blow by.

Three on the tree, four on the floor. The gear change mechanism is a component that is too often taken for granted but it is one of the more important features of the vehicle. It must be quick and smooth in action, efficient and totally reliable. Modern driving conditions demand that the driver makes frequent gear changes and a mechanism that is temperamental or inaccurate can be both frustrating and dangerous as well as physically tiring. The gear changing mechanism starts, quite obviously, with the gear lever. Most stem from the fact that a gear lever must move in two planes, forward and back and then from side to side to move across the gear "gate". A good many drivers think of gear changing as one simple action. This is more a tribute to the design of gear changing mechanisms than a reality. There are multiple gear selector mechanisms that are available for use in commercial vehicle industry.

A propeller shaft is a mechanical component of drive train that connects transmission to drive wheels/axle with the goal to transfer rotation and torque. It is used when the direct connection between transmission and drive axle is not possible due to large distance between their respective assigned design spaces. In commercial vehicles especially in heavy duty (GVW/GCW>15 tons) a single piece propeller shaft is seldom used due to its inherent disadvantages and therefore, most if not all, of the setups consists of multiple pieces of propeller shaft which are directly mounted on to frame cross members with the help of mounting brackets. As such the mounting bracket assembly undergoes various dynamic and static loading conditions and should be able to withstand these loads. This paper will focus on the FEA analysis of propeller shaft mounting assembly system. Furthermore, these results will be correlated with physical tests results collected from test rig and physical vehicle testing.

An engine cooling system is required to maintain stable operating temperature for the engine and prevent it from overheating. Thermal distortion of engine parts can take place if proper cooling is not maintained and engine may loss efficiency. One of the major problem in this domain is to incorporate separate cooling systems for the different variants of engines (different power rating). A single optimized cooling unit is desired to manage the entire range of engine rated power. The factors that affect the cooling system are front end grill opening area, air recirculation, location of snorkel inlet, radiator core size, which need to be tuned to get appropriate results. The above parameters are tuned to obtain appropriate results using the Computational Fluid Dynamics (CFD) simulations. In the next stage, on road cooling trials are performed and real time data is collected.

The safety of the heavy duty commercial vehicle (HCV) occupants in an accident is an imperative task and should be considered during the design and development of cabins. The sufficient cabin survival space must be remained after the accident. The main aim of this study is to develop a Finite Element (FE) model of HCV cabin and validate to the test as per AIS029. The present study also includes the assessment of the energy absorption capabilities of the HCV cab during the pendulum impact test. Initially a detailed 3D FE model of a fully suspended HCV cabin was developed and then pendulum impact test simulation was carried out using LS-Dyna explicit solver. Simulation results were compared with the test results and were found in a great agreement in terms of survival space and overall deformation behavior. The load transfer path was described at the time of pendulum impact. The largest amount of impact energy was absorbed by the frontal region of the cabin.

India being a developing nation, there is significant improvement of road infrastructure across the country as well as the spending power and earnings of the common man. This leads to the new trend of customers willing to pay for a more comfortable travel through AC buses. To satisfy these demands, OEM’s are forced develop and manufacture huge numbers of AC buses. Although the OEM’s are meeting this demand of quantity, the quality aspect of the buses, i.e., climate comfort, is still subpar. One of the main reasons for this sub-quality comfort is the non homogenous distribution of air flow along the bus. This non homogeneity leads to the centre of the bus having very high air flow and thus overcooling conditions, while the front and rear of the bus receive very little air flow and thus receive under-cooling conditions. To solve this concern of non homogeneity, we incorporated a new design in the hatrack, through the implementation of baffles and deflector in the hatrack.

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.

In recent times there has been rising demand for noise level reduction in commercial vehicles. Vehicle engine exhaust system is one of the key sources of noise at driver ear, especially in smaller wheel base vehicles, as well as critical for meeting pass by noise regulations. Several techniques are used to reduce the noise level of an exhaust system such as resonators, dissipative mufflers for low & high frequencies respectively. In this paper sound transmission loss (STL) measurement for a LMD bus exhaust system was carried out at rig level. It has been found from the measured data that noise attenuation of current exhaust system is poor in low frequency zone & therefore lower STL frequencies were identified. To attenuate the noises at identified frequencies Helmholtz resonator was introduced, which is particularly effective for low frequency noise attenuation.

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.