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The paper describes a first-of-its-kind attempt of authors to develop an intake manifold - combined with - rocker cover (IMCRC) in sheet molding compound (SMC) for 3 L and 4 L direct injection diesel engines with power ratings 75 kW and 92 kW respectively. The objective was to reduce overall engine weight, noise and cost. The intake manifold is designed to withstand absolute boost pressures of more than 2 bar, temperature in the range of 160 °C. and capable of carrying load of directly attached components such as an air intake pipe. It is worth to note that the designed SMC component always remains in the vicinity of the exhaust manifold by virtue of base engine layout constraint. The development if successful can expand the horizon of SMC in diesel engine application.

The ever-tightening regulation norms across the world emphasize the magnitude of the air pollution problem. The decision to leapfrog from BS4 to BS6 – with further reduction in emission limits -showed India’s commitment to clean up its atmosphere. The overall cycle emissions were reduced significantly to meet BS6 targets [1]. However, the introduction of RDE norms in BS6.2 [1] demanded further reduction in emissions under real time operating conditions – start-stop, hard acceleration, idling, cold start – which was possible only through strategies that demanded a cost effective yet robust solutions. The first few seconds of the engine operation after start contribute significantly to the cycle gaseous emissions. This is because the thermal inertia of the catalytic converter restricts the rate at which temperature of the catalyst increases and achieves the desired “light-off” temperature.

Gasoline engines with Multi point fuel injection (MPFI) technology are being developed with naturally aspirated and/or turbocharged engines. Wherein a MPFI and turbo charged combination engines have certain challenges during development stages. One of the important challenge is design of air intake and exhaust system. With MPFI turbocharged engine combination, the under bonnet heat management is crucial task for drivability. The heat management of air intake plays a vital role in drivability part therefore a design layout of air intake path is an important aspect. Drivability can be categorized as low end, mid-range and top end drivability. Turbocharged MPFI engines have a typical phenomenon of ‘Lag in response’ in the low-end region. This ‘Lag in response’ phenomenon at low-end drivability region can be overcome through optimization of air intake system and optimization of exhaust back pressure.

Petroleum Oil, Lubricants (POL) & Liquefied petroleum gas (LPG) tanker vehicles are special application segment that holds a significant Market share for commercial vehicles. These vehicles need to comply additional Safety regulations specified by Petroleum and explosives safety organization (PESO). For compliance to Rule-70, Protective heat shield on exhaust system needs to be designed and validated in order to avoid any catastrophic failure. The paper demonstrates the methodology to identify the worst case scenario for the existing commercial vehicle segment. Based on detail digital mock up (DMU) review Metallic heat shield was designed on after treatment system (ATS). The flexible heat shield was designed for exhaust pipe & joints in order to restrain the heat flow to the surrounding aggregates. After finalising design, CFD analysis was carried out to find out the thermal effects on various components and results within acceptable limits.

The basic function of steering system is to control the direction of the vehicle. The driver applies effort on the steering wheel and receives feedback through the steering system as a result of tire to road interaction. This feedback consists of a haptic (force) feedback which is directly felt by the driver and it is termed as steering feel. Precise steering feel gives better driving experience and is decisive factor for customer to buy a vehicle as well as for OEMs in building brand image. Along with steering parameters, suspension and tire parameters also has significant impact on steering feel. In past, modelling of the steering system was done at component level or with simplified vehicle system. Such approaches had not given accurate results of steering feel metric and resulted in incorrect steering design parameter selection. In order to replicate actual vehicle characteristics, complex and detailed modelling of steering, tire and suspension subsystems is necessary.

Primarily, Acoustic performance of muffler are evaluated by insertion loss (IL) and backpressure/restriction. Where Insertion loss is mainly depends upon proper selection of muffler volume, which is proportional to Engine Swept volume, along with internal design configuration, which drives the acoustic principle. Same time, meeting the vehicle level pass by noise (PBN) value as per regulatory norms and system level backpressure as per engine specification sheet are the key evaluating criteria of any good exhaust system. Here, a new Reactive/Reflective type muffler of tiny size have been designed for heavy commercial vehicle application, which is unique in shape and innovative to meet desire performance. In this design, mainly sudden expansion, sudden contraction, flow through perforation and bell-mouth flow phenomenon are used.

This research paper is dealing with development of a Hybrid Exhaust muffler with four different shell configurations (Internal design unaltered) and investigated the impact on noise performance and quality (perceived). Noise performance has been evaluated by measurement of Pass by Noise and near exhaust noise Level on a typical 16T -6-speeds transmission Truck. The experimental activity conducted based on DOE approach. From this study, it observed single shell with lower thickness have the poor NVH performance and perceived quality as well. Shell or booming noise is also observed with this configuration. Double shell with Ceramic blanket (throughout the length) sandwich configuration exhibited the best performance though this design is most expensive among the four mufflers.

The dynamic response of structures to operating or occasional loads is crucial for design considerations, as it directly impacts the cumulative fatigue life. In practice, accurately discerning the precise loads and structural conditions, which involve considerations such as boundary conditions, geometry, and mechanical properties, can be quite challenging. Significant efforts are invested in identifying these factors and developing suitable prediction models. Nonetheless, the estimated forces and boundary conditions remain approximations, leading to uncertainties which affects the overall predictions and the analysis of how stress and strain develop in the structure during subsequent evaluations. Many researchers frequently employ a method where they estimate the forces acting on the system based on measurement data obtained at limited number of locations over the structure.

For an automotive exhaust system, noise level and back pressure are the most important parameters for passenger comfort and engine performance respectively. The sound quality perception of the existing silencer design was unacceptable, although the back pressure measured was below the target limit. To improve the existing design, few concepts were prepared by changing the internal elements of silencer only. The design constraints were the silencer shell dimensions, volume of silencer, inlet pipe and outlet tailpipe positions, which had to be kept same as that of the existing base design. The sound quality signal replaying and synthesizing was performed to define the desired sound quality. The numerical simulation involves 3D computational fluid dynamics (CFD) with appropriate boundary condition having less numerical diffusions to predict the back pressure. The various silencer concepts developed with this preliminary analysis, was then experimentally verified with the numerical data.

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.

Diesel engines tend to operate on lower exhaust temperatures, compared to their gasoline counterparts. Exhaust emission control becomes a significant issue at these lower temperatures, as any catalytic converter needs certain light off temperature to commence functioning. The trend so far has been to move the catalytic converters closer to the exhaust manifold, in order to get the benefit of higher temperatures - but most of the applications are limited to the location available after the turbo chargers. This is due the fact that very minute and efficient catalyst is required, if it has to be placed before the turbo charger. This catalyst also needs to be extremely durable to take care of high exotherms which occur within the catalysts and also to prevent any possible damage to the turbo chargers.

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.

Customer preference towards quieter vehicles is ever-increasing. Exhaust tailpipe noise is one of the major contributors to in-cab noise and pass-by-noise of the vehicle. This research proposes a silencer with an integrated acoustic valve to reduce exhaust tailpipe noise. Incident exhaust wave coming from the engine strikes the acoustic valve and generates reflected waves. Incident waves and reflected waves cancel out each other which results in energy loss of the exhaust gas. This loss of energy results in reduced noise at the exhaust tailpipe end. To evaluate the effectiveness of the proposed silencer on the vehicle, NVH (Noise, vibration, and harshness) performance of the proposed silencer was compared with the existing silencer which is without an acoustic valve. A CNG (Compressed natural gas) Bus powered by a six-in-line cylinder engine was chosen for the NVH testing.

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.

With India achieving the BSVI milestone, the diesel particulate filter (DPF) has become an imperative component of a modern diesel engine. A DPF system is a device designed to trap soot from exhaust gas of the diesel engine and demands periodic regeneration events to oxidize the accumulated soot particles. The regeneration event is triggered either based on the soot mass limit of the filter or the delta pressure across it. For a Heavy Duty Diesel Engine (HDDE), pressure difference across the DPF is not usually reliable as the size of the DPF is large enough compared to the DPF used ina passenger vehicle diesel engine. Also, the pressure difference across DPF is a function of exhaust mass flow and thus it makes it difficult to make an accurate call for active regeneration. This demands for a very accurate soot estimation model and it plays a vital role in a successful regeneration event.

Sound signature design is gaining more importance within global auto manufacturers. ‘Sportiness’ is one of the important point to consider while designing a sound character of a car for passionate drivers and those who love aggressive driving. Nowadays automobile manufacturers are more focused in developing a typical sound signature for their cars as a ‘unique design strategy’ to attract a niche segment of the market and to define their brand image. Exhaust system is one of the major aggregate determining the sound character of ICE vehicles which in turn has the direct influence on the customer perception of the vehicle and the Brand image and also the human comfort both inside and outside the cabin. This research work focuses on novel approaches to identify frequency range and order content by a detailed study of subjective feelings based on psycho-acoustics. Sound samples of various benchmark sporty vehicles have been studied and analyzed based on sound quality parameters.