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1 With increasing fuel price, the power train size is on a downward trend. For Fuel Economy maximization, the engine capacity and reduction ratios are getting reduced. So gradability of a vehicle is becoming a trade off factor for the power train size finalization in a car. At the same time OEMs are working hard to maintain profitability by reducing development and operational cost and time. In this complexly competitive scenario in automobile manufacturing, simulation is gaining an upper hand over actual testing as simulation consumes lesser time and resource as compared to actual testing. This paper is aimed at developing a simulation technique for restart or stop and start gradability which is a very critical parameter for finalization of engine torque characteristics and power train configuration. The simulation is done on AVL-CRUISE software.

The power output of an internal combustion engine is directly proportional to the amount of air that can be forced into the cylinder per cycle and the amount of fuel that can be burned efficiently. The amount of air is most effectively increased by means of a mechanical supercharger. The purpose of this paper is attempting the non mechanical supercharging ways (Supercharging by means of gas dynamic effects) for naturally aspirated (NA) diesel engines and understanding in a better way the induction gas dynamics and its influence on engine performance characteristics. Wave dynamics in the intake system has strong influence on the performance of naturally aspirated internal combustion (IC) engines. This paper presents an application of Helmholtz resonator in the induction system of the naturally aspirated diesel engine to improve the engine breathing efficiency (volumetric efficiency).

In the automotive industry, silicon adhesive has become increasingly popular due to its benefits in ease of assembly and cost savings associated with material and manufacturing processes. To meet the imperative of minimizing both time and expenses during the project's development phase, it becomes essential to select the appropriate gasket material and an optimal flange design at the outset of the design process. In order to achieve stringent emission standards such as Real Driving Emission (RDE) and Corporate Average Fuel Economy (CAFE) norms, a better sealing performance is an essential parameter. Various types of liquid gaskets such as silicon rubber based Room Temperature Vulcanizing (RTV) sealants and thermoset plastic based Anaerobic sealants are widely used in an Internal Combustion engine. They are commonly used for the components such as oil sump, bedplate, and gearbox housings, etc.

High strength aluminium alloys are an ideal material in the automotive sector leading to a significant weight reduction and enhancement in product safety. In recent past extensive development in the field of high strength steel and aluminium was undertaken. This development has been propelled due to demand for light weight automotive parts. The high strength to weight ratio possessed by Al alloy helps in reducing the total weight of the vehicle without effecting the overall performance, thereby increasing the fuel economy, and reducing the carbon emission level. Joining of high strength aluminium alloy is critical to develop durable automotive products. Joining of high strength aluminium alloy for mass production in automobile industry is a challenging task. Laser welding is recognized as an advanced process to join materials with a laser beam of high-power, high- energy density.

Regenerative braking has become one of the major features for a hybrid vehicle as it converts brake energy into electrical energy storable into battery and leads to an increase in overall fuel efficiency of the vehicle. Traditional regenerative braking systems are designed such that the mechanical braking force from the friction brakes is varied in order to get maximum electric braking. This is the optimum method; however, such a system calls from electronics (Anti-lock Braking System) for regulation of mechanical braking leading to an increased cost. In this paper, the authors present a new strategy for implementing a regenerative brake strategy without changing the mechanical brake system of a conventional vehicle converted to a hybrid vehicle. The electric motor that serves as the traction motor or the Integrated Starter Generator (ISG) system, is used for regenerative braking also. There is no change in the other vehicle specifications as compared to the conventional vehicle.

In cold climatic regions (25°C below zero) thermal comfort inside vehicle cabin plays a vital role for safety of driver and crew members. This comfortable and safe environment can be achieved either by utilizing available heat of engine coolant in conjunction with optimized in cab air circulation or by deploying more costly options such as auxiliary heaters, e.g., Fuel Fired, Positive Temperature Coefficient heaters. The typical vehicle cabin heating system effectiveness depends on optimized warm/hot air discharge through instrument panel and foot vents, air directivity to occupant's chest and foot zones and overall air flow distribution inside the vehicle cabin. On engine side it depends on engine coolant warm up and flow rate, coolant pipe routing, coolant leakage through engine thermostat and heater core construction and capacity.

Most of the energy consumed in today's mobility industry is derived from fossil fuels. The demand for clean, renewable and affordable alternative energy is forcing the automotive industry to look beyond the conventional fossil fuels. Fuels options like liquefied petroleum gas (LPG), compressed natural gas (CNG) and ethanol blends are quickly finding widespread acceptance as alternative sources. This paper presents the results of experimental studies conducted on a 1.2-liter MPI engine with three different alternate fuels. The fuels considered for the evaluation (apart from base gasoline) are 10% ethanol-blended fuel (E10), LPG (gaseous propane: butane mix) and CNG (gaseous methane). Experiments were conducted to compare their effect on engine performance and emissions. The test results show that E10 has the lowest power drop whereas CNG has the highest power drop (12%) as compared to gasoline. The maximum power drop in LPG is 4%, which is close to the theoretical predictions.

Depletion of fossil fuel reserves, the unsteadiness of their prices and the increasingly stricter exhaust emission legislation put forward attention of world towards use of alternate fuels. The ever increasing demand for ecologically friendly vehicles can be met by use of clean fuels like Compressed Natural Gas (CNG) and Hydrogen (H2). Lower carbon to hydrogen ratio of CNG makes it a cleaner fuel, due to this CNG is gaining popularity as an internal combustion (IC) engine fuel in transport sector. Hydrogen fuel for IC engines is also being considered as a future fuel due to its simple carbon less structure. However, several obstacles have to be overcome before widespread utilization of hydrogen as an IC engine fuel can occur in the transport sector. The 18 percent hydrogen enriched CNG fuel referred to as HCNG has the potential to lower emissions and could be considered a first step towards promotion of a Hydrogen economy.

In a heavy commercial vehicle, the engine cooling package is designed by considering peak heat load on the vehicle cooling system from an engine end. In cooling systems, the major unit that consumes most power from the engine is the engine cooling fan. It was seen from the vehicle measured duty cycle data, for most of the time engine operates at part load condition. Regardless of demand from the engine cooling system, engine fan was operating continuously at equivalent speed of the engine. This results in continuous consumption of productive engine power from the fan end ultimately affecting vehicle fuel economy. The present study shows that low idle speed viscous fan has the potential to meet stringent engine cooling performance requirements and consumes less engine power throughout an actual vehicle duty cycle. Experiments were conducted on test vehicle with different fan speeds.

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.

Important vehicle performance parameters such as, fuel economy and high speed stability are directly influenced by its aerodynamic drag and lift. Wind tunnel testing to asses these parameters requires heavy investment especially when test wind tunnel is not available in the country where vehicle development center is present. Hence to save cost and to compress development time, it is essential to asses and optimize parameters of a vehicle in very early stages of development. Using numerical flow simulations optimization runs can be carried out digitally. Industry demands prediction of aerodynamic drag and lift coefficients (CD,CL) within an accuracy of a few counts, consuming minimal HPC resources and in a short turnaround time. Different OEMs deploy different testing methods and different softwares for numerical simulations.

Advent of EV powertrain has considerable effect on transmission development activities as competed to regular ICE transmission. Conventional ICE transmission and the transmission for an e-powertrain differ on fundamental level. The conventional transmission has number of gear ratios, shift mechanism which enables the transmission to deliver a smooth power output as per demand from the driver. Whereas the e-powertrain transmission is mostly a single gear ratio transmission (reducer) which primarily depends on speed and torque variation from the motor to cater the driver requirement. Hence, the operating speeds of such e-transmissions can vary from 0 to 20000 rpm in both forward and reverse directions. Such a large speed variation as compared with conventional transmission calls for special attention towards the lubrication of internal components. High speeds and lower oil viscosities tend to disrupt the oil films in between contact surfaces causing metal to metal contact.

A hybrid electric powertrain being a complex system requires analysis of all its subsystems to optimally utilize, size components for performance evaluation and control strategy development. An integrated high fidelity model of these can lower development costs, time and achieve the targeted performance while allowing for early redefinition of the system. A high fidelity model of a sedan car featuring chassis with longitudinal and lateral dynamics, suspension with joints, tires calculating longitudinal & lateral forces during vehicle motion, Engine model with combustion & dynamics of reciprocating and rotating components, Electric motors, Battery system, and gearbox with synchronizers and friction components was developed. Powertrain components were interconnected using 3D rotational flanges. Weight distribution was accomplished by appropriately locating various powertrain components using 3D supporting mounts, which help to study the mount forces as well.

Liquefied Petroleum Gas (LPG)-powered vehicles use a pressure regulator/vaporizer to expand and modulate the gas pressure to meet the engine's operational demands. This expansion process is accompanied by a phase change wherein liquid LPG is converted to its gaseous form. This consequently reduces the temperature of the working fluid which may result in freezing (Joule-Thompson effect). In order to aid complete phase change and avoid any freezing, the vaporizer is heated either electrically or by the engine coolant circulation. Any inefficiency in the heating may lead to improper phase change and can result in a phenomenon known as "liquid carryover," wherein a liquid LPG gets entrained in the downstream gas circuit where the gaseous form is demanded. The liquid carryover (if any) leads to the improper engine functioning leading to driveability and emission issues.

An emissions, combustion noise and performance study were conducted to explore the effects of two different multiple injections strategies on emissions, combustion noise and performances without altering EGR %. The experiments were done on a six cylinder inline CRDI diesel production engine. The aim of this study is to improve performances (brake specific fuel consumption [BSFC], torque) and combustion noise (reduction) using multiple injection strategies without violating emission regulations. The other objective of this carried-out analysis is to examine the influence of different operating parameters (Speed and Load) and main injection timing combined, on same multiple injection strategies (Pilot- main – after {PMA}and Early - pilot- main –after {EPMA}) by means of analyzing emissions/soot, combustion noise and performances data.

The world today is majorly dependent upon fossil fuels for power generation, of which diesel forms an integral part. Diesel engines, having the highest thermal efficiency of any regular internal or external combustion engine, are widely used in almost all walks of life and cannot be dispensed with in the near future. However, the limited availability of diesel and the adverse effects of diesel engine emissions like nitrogen oxide (NOx) and soot particles raise serious concerns. Hence, their performance and emission improvement continues to be an avenue of great research activity. In this research work, the effects of blending Diethyl Ether with diesel in various proportions (5%, 10%, 15% and 20% by volume) were evaluated on engine performance and emissions of an industrial internal combustion engine.

The objective of the work presented in this paper is to provide an overall CFD evaluation and optimization study of cabin climate control of air-conditioned (AC) city buses. Providing passengers with a comfortable experience is one of the focal point of any bus manufacturer. However, detailed evaluation through testing alone is difficult and not possible during vehicle development. With increasing travel needs and continuous focus on improving passenger experience, CFD supplemented by testing plays an important role in assessing the cabin comfort. The focus of the study is to evaluate the effect of size, shape and number of free-flow and overhead vents on flow distribution inside the cabin. Numerical simulations were carried out using a commercially available CFD code, Fluent®. Realizable k - ε RANS turbulence model was used to model turbulence. Airflow results from numerical simulation were compared with the testing results to evaluate the reliability.

This paper focuses on factors that enhance energy efficiency of air conditioning system on mid-sized, standard and premium buses with engine power from 125 to 280 HP. It covers aspects like light weighting of roof air conditioning system, usage of optimized ducting system with minimal resistance to blowers, deployment of rotary scroll compressor with fast idle control in place of reciprocating piston compressor. The scope of this paper covers AC compressors driven by main engine of vehicle/ bus, study related to auxiliary/donkey engine driven AC compressor is not considered. Context- In order to enhance fuel efficiency in buses an energy efficient air conditioning system should be deployed. This will lead to reduced parasitic load on the engine and translate into direct fuel saving.

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.