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Gasoline direct injection (GDI) engines have gained popularity in the recent times because of lower fuel consumption and exhaust emissions compared to that of the conventional port fuel injection (PFI) engine. But, in these engines, the mixture formation plays an important role which affects combustion, performance and emission characteristics of the engine. The mixture formation, in turn, depends on many factors of which fuel injector location and orientation are most important parameters. Therefore, in this study, an attempt has been made to understand the effect of fuel injector location and nozzle-hole orientation on the mixture formation, performance and emission characteristics of a GDI engine. The mixture stratification inside the combustion chamber is characterized by a parameter called “stratification index” which is based on average equivalence ratio at different zones in the combustion chamber.

Today, homogenous charge compression ignition (HCCI) engines are becoming very popular because of their potential to reduce soot and nitric oxides (NOx) emissions simultaneously. But, their performance and emission characteristics are very much dependent upon fuel injection strategy and parameters. However, they also have many challenges viz., improper combustion phasing, high rate of pressure rise and narrow operating range. Therefore, addressing them is very essential before making them a commercial success. This study focuses on evaluating the effect of fuel injection strategy and parameters on the performance and emission characteristics of a HCCI engine by computational fluid dynamics (CFD) analysis. In this study, a four-stroke engine operating in the HCCI mode is considered and the CFD analysis is carried out by using the CONVERGE.

Formability of metals and alloys in general and aluminium alloys and steels in particular is of paramount importance in sheet metal forming in automobile industry. It is well understood that the evolution of preferred crystallographic orientation of crystallites or texture during prior thermo-mechanical processing of sheets plays an important role in determining formability. The formability of sheet is measured in terms of the Lankford parameter or the plastic strain ratio which is defined as the ratio of strain in width direction to that in the thickness direction (R = εw/εt). The variation of Lankford parameter with the rolling direction and standard and ΔR value is widely used in industry as a standard for estimating the formability of the rolled sheets.

Effective control of exhaust emissions from modern diesel engines requires the use of aftertreatment systems. Elevated aftertreatment component temperatures are required for engine-out emissions reductions to acceptable tailpipe limits. Maintaining elevated aftertreatment components temperatures is particularly problematic during prolonged low speed, low load operation of the engine (i.e. idle, creep, stop and go traffic), on account of low engine-outlet temperatures during these operating conditions. Conventional techniques to achieve elevated aftertreatment component temperatures include delayed fuel injections and over-squeezing the turbocharger, both of which result in a significant fuel consumption penalty. Cylinder deactivation (CDA) has been studied as a candidate strategy to maintain favorable aftertreatment temperatures, in a fuel efficient manner, via reduced airflow through the engine.

Predicting the brake performance and characteristics is a crucial task in the vehicle development activity. Performance prediction is a challenge because of the involvement of various parts in the brake assembly like booster, master cylinder, calipers, disc and drum brakes. Determination of these characteristics through vehicle level tests requires a lot of time and money. This performance prediction is achieved by theoretical calculations involving vehicle dynamics. The final output must satisfy the regulations. This project involves the creation of a standalone application using MATLAB to predict the various brake performances such as: booster characteristics, adhesion curves, deceleration and pedal effort curves, behavior of brakes during brake and booster failed conditions and braking force diagrams based on the given user inputs. Previously, MS Excel and an application developed in the TK Solver environment was used to predict the brake performance curves.

Severe air pollution in cities caused largely by vehicular emissions, which requires urgent remedial measures. As automobiles are indispensable modes of personal and public mobility, pre-emptive efforts are necessary to reduce the adverse effects arising from their operation. A significant improvement in air quality can be achieved through large-scale introduction of vehicles with extremely low emission such as hybrid-electric and zero emission vehicles. Range extension of electric vehicles (EVs) is also of utmost importance to alleviate the handicap of restricted mileage of purely plug-in EVs as compared to conventional vehicles. This paper presents development of a polymer electrolyte membrane (PEM) fuel cell stack used for the range extender electric vehicles. The Fuel cell stack for range extender vehicle operated in a dead end mode using hydrogen and air as open cathode.

Improving vehicle performance in terms of both torque and power is a strong customer need in both conventional and electric vehicles. In this work, different two speed automatic transmission (AT) concepts are developed to improve the energy efficiency and performance of battery electric two wheelers. Developed transmission systems are simple, compact and cost effective and results in relatively high energy efficiency of an electric motor. The unique shift control strategy ensures motor to operate at higher efficiency zones to minimize the overall energy consumption. Virtual simulations of electric vehicle were carried out for different driving conditions and optimal transmission ratios were determined. Mechanical behaviors such as gear shift characteristics, linear and angular velocities, inertial forces of each components are analyzed by using Multi body dynamics simulation. Forces predicted here are further used for durability studies of these components.

Three catalysts based on X-zeolite have been developed by exchanging its Na+ ion with Copper, Nickel and Vanadium metal ions and tested in a stationary SI engine exhaust to observe their potentialities for NOx and CO controlling. The catalyst Cu-X, in comparison to Ni-X and V-X, exhibits much better NOx and CO reduction performance at any temperature. Maximum NOx conversion efficiencies achieved with Cu-X, Ni-X and V-X are 62.2%, 59.7% and 56.1% respectively. Unlike noble metals, the doped X-zeolite catalysts, studied here, maintain their peak NOx reduction performance through a wider range of A/F ratio. Back pressure developed across the catalyst bed is found to be well within the acceptable limits.

Modern combat aircraft demands efficient maintenance strategies to ensure operational readiness while minimizing downtime and costs. Innovative approaches using Digital Twining models are being explored to capture inter system behaviours and assessing health of systems which will help maintenance aspects. This approach employs advanced deep learning protocols to analyze the intricate interactions among various systems using the data collected from various systems. The research involves extensive data collection from sensors within combat aircraft, followed by data preprocessing and feature selection, using domain knowledge and correlation analysis. Neural networks are designed for individual systems, and hyper parameter tuning is performed to optimize their performance. By combining the outputs of these during the model integration phase, an overall health assessment of the aircraft will be generated.

Graphite plays a crucial role in friction materials, since it has good thermal conductivity, lubricity and act as a friction modifier. The right type, amount, shape, and size of the particles control the performance of the brake-pads. The theme of the study was investigating the influence of size of graphite particles (having all other specifications identical) on performance properties of brake-pads containing graphite particles in the average size of 60 μm, 120 μm, 200 μm and 400 μm. Physical, mechanical and chemical characterization of the developed brake-pads was done. The tribological performance was studied using a full- scale inertia brake dynamometer following a Japanese automobile testing standard (JASO C406). Tribo-performance in terms of fade resistance, friction stability and wear resistance were observed best for smaller graphite particles. It was concluded that smaller size serves best for achieving best performance properties barring compressibility.

There is a growing need for improved conceptual vehicle designs along with alternative materials to reduce the damage to the passengers and structures in aerospace and automotive industries. The energy absorption characteristics of materials play a major role in designing a safe vehicle for transport. In this paper, compression behavior and energy absorption of aluminum alloy AA6061 and AA7005 tubes in T4 and T6 conditions are investigated by experimental and numerical methods. The AA7005 and AA6061 tubes are solution heat treated and then aged to achieve the final strength in T6 condition. Experimental compression test results have shown improved energy absorption of tubes in T6 condition compared to tubes in T4 condition. There is less variation of energy among the tested samples. The mean load is compared with the results obtained from analytical formulae. Tensile properties have been obtained from tensile tests using UTM for both AA6061 and AA7005 tubes.

Increasing the efficiency of engine auxiliary systems have become a challenge. Oil pump, identified for this study, is one such engine system which is used for lubrication of engine parts. To achieve higher efficiencies, there is a need for math-based analysis and design. This can be achieved by means of Computational Fluid Dynamics (CFD). The main aim of this paper is to simulate the flow through Gerotor Oil pump using Computational Fluid Dynamics. A 3D model of the entire flow domain is created and meshed in preprocessor GAMBIT. The mesh for various pressure outlet conditions is exported to FLUENT solver for analysis. The predicted results are validated with the experimental results. The comparison shows that the CFD predictions are in good agreement with experimental results. In particular, such a simulation offers a scope for visualizing the flow through the Gerotor oil pump.

Gasoline Direct Injection (GDI) engine is known for its higher power and higher thermal efficiency. Researchers are steadily determining and resolving the problems of fuel injection in a GDI engine. In order to meet the stringent emission norms such as PM and NOx emitted by a GDI engine, it is necessary to investigate the microscopic spray characteristics and fuel-air mixing process. This paper aims to share the fundamental knowledge of the interacting mixture preparation mechanisms at the wide range of fuel injection pressures. The investigations were carried out at five different fuel injection pressures viz: 40, 80, 120, 160, 200 bar, for 24 mg fuel per injection. A high speed CCD camera was used to determine the macroscopic spray characteristics of the GDI injector. It was found that spray penetration length increased with increasing fuel injection pressure. Phase Doppler Interferometry (PDI) was used to determine the droplet size and droplet velocity for different test fuels.

Yaw rate of a vehicle is highly influenced by the lateral forces generated at the tire contact patch to attain the desired lateral acceleration, and/or by external disturbances resulting from factors such as crosswinds, flat tire or, split-μ braking. The presence of the latter and the insufficiency of the former may lead to undesired yaw motion of a vehicle. This paper proposes a steer-by-wire system based on fuzzy logic as yaw-stability controller for a four-wheeled road vehicle with active front steering. The dynamics governing the yaw behavior of the vehicle has been modeled in MATLAB/Simulink. The fuzzy controller receives the yaw rate error of the vehicle and the steering signal given by the driver as inputs and generates an additional steering angle as output which provides the corrective yaw moment.

Road accidents and persons killed in India have been reported to the tune of 4,90,383 and 1,38,258 respectively during 2012. On National Highways (NHs), major share of accidents (about 29%) and number of persons killed (35.3%) are observed out of total accidents. National Highways in India constitute about 2% of total road network (92,851 km) in India, but carries about 40% of traffic. 46% (42,829 km) of NHs in India comprises of two-lane and about 19% (17239 km) of NHs are single or intermediate-lane. Road accidents being multi-disciplinary in nature involves attention of multiple departments such as Highways Authority, Police, Motor Vehicles, Automobile Manufacturers, NGOs, etc. Owing to spurt in growth of motor vehicle population in India, road accidents are not reduced significantly despite improvement in NHs (widening of carriageway and riding quality).

The upcoming Bharat Stage VI (BS VI) emission legislation has put enormous pressure on the future of small diesel engines which are widely used in the Indian market. The present work investigates the emission reduction potential of a common rail direct injection single cylinder diesel engine by adopting a holistic approach of lowering the compression ratio, boosting the intake air and down-speeding the engine. Experimental investigations were conducted across the entire operating map of a mass-production, light-duty diesel engine to examine the benefits of the proposed approach and the results are quantified for the modified Indian drive cycle (MIDC). By reducing the compression ratio from 18:1 to 14:1, the oxides of nitrogen (NOx) and soot emissions are reduced by 40% and 75% respectively. However, a significant penalty in fuel economy, unburned hydrocarbon (HC) and carbon monoxide (CO) emissions are observed with the reduced compression ratio.

In a direct-injection (DI) engine, charge motion and mixture preparation are among the most important factors deciding the performance and emissions. This work was focused on studying the effect of injector positioning on fuel-air mixture preparation and fuel impingement on in-cylinder surfaces during the homogeneous mode of operation in a naturally aspirated, small bore, 0.2 l, light-duty, air-cooled, four-stroke, spark-ignition engine modified to operate under the DI mode. A commercially available, six-hole, solenoid-operated injector was used. Two injector locations were identified based on the availability of the space on the cylinder head. One location yielded the spray-guided (SG) configuration, with one of the spray plumes targeted towards the spark plug. In the second location, the spray plumes were targeted towards the piston top in a wall-guided (WG) configuration so as to minimize the impingement of fuel on the liner.

Advanced low temperature combustion (LTC) modes are most promising to reduce green house gas emissions owing to fuel economy benefits apart from simultaneously reducing oxides of nitrogen (NOx) and particulate matter (PM) emissions from diesel engines. Various LTC strategies have been proposed so far and each of these LTC strategies have their own advantages and limitations interms of precise ignition control, achievable load range and higher unburned emissions. In the present work, a small single cylinder diesel engine is initially operated under conventional combustion mode at rated speed, varying load conditions to establish the base line reference data. Then, the engine is modified to operate under different LTC strategies including Homogenous Charge Compression Ignition (HCCI), Premixed Charge Compression Ignition (PCCI) and Reactivity Controlled Compression Ignition (RCCI).

Reactivity controlled compression ignition (RCCI) is one of the most promising low temperature combustion (LTC) strategies to achieve higher thermal efficiencies along with ultra low oxides of nitrogen (NOx) and particulate matter emissions. Small single cylinder diesel engines of air-cooled type are finding increasing applications in the agriculture pump-set and small utility power generation owing to their lower cost and fuel economy advantages. In the present work, a small single cylinder diesel engine is initially operated under conventional combustion mode at rated speed, varying load conditions to establish the base line reference data. Then, the engine is modified to operate under RCCI combustion mode with a newly designed cylinder head to accommodate a high pressure, fully flexible electronically controlled direct diesel fuel injection system, a low pressure gasoline port fuel injection system and an intake air pre heater.

Hydrodynamic parameters play a major role in the dynamics and control of Autonomous Underwater Vehicles (AUV). The performance of an AUV is dependent on the parameter variations and a proper understanding of these parametric influences is essential for the design, modelling and control of high performance AUVs. In this paper, a six sigma framework for the sensitivity analysis of a flatfish type AUV is presented. Robust design techniques such as Taguchi’s design method and statistical analysis tools such as Pareto-ANOVA, and ANOVA are used to identify the hydrodynamic parameters influencing the dynamic performance of an AUV. In the initial study, it is found that when the vehicle commanded in forward direction, it is in bow down configuration which is unacceptable for AUV motion. This is because of the vehicle buoyancy and shape of the vehicle. So the sensitivity analysis of pitch angle variation is studied by using robust design techniques.