Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

We demonstrated the preparation of polyvinyl alcohol (PVA) /Potassium titanate (K2Ti6O13) synthetic composite by solution blending. The loading of K2Ti6O13 well dispersed in PVA and improved electrical performance. The dielectric constant and loss as a function of temperature were recorded under frequency (200Hz-1 kHz). The real dielectric constant value obtained is (ε=1000) feasible for various electronic and non-conventional energy applications.

VIT Unitversity

Department of Physics

School of Advanced Sciences

Vellore Campus

Department of Automotive Engineering

School of Mechanical Engineering

World University root node

AIP Conference Proceedings

PVA/K2Ti6O13 synthetic composite for dielectric applications

In Conventional internal combustion engine cooling system, the coolant pump is belt-driven by the engine crankshaft. The direct coupling between engine and cooling pump results in an excessive flow of cooling fluid at part-load conditions and waste of energy in running the pump at engine cold start, which affects the engine efficiency and, as a consequence, the global fuel consumption. A study has been conducted on a Maruti 800cc MPFI engine cooling system in order to find a way to reduce common overheating problems at idle conditions and intermediate engine speeds with restricted airflow. The study involves testing of an engine radiator in a wind tunnel (calorimeter) to simulate the actual driving conditions. The coolant flow rate, pressure, and temperature characteristics were monitored at different positions in the cooling system while engine speed and load was varied. Engine performance test were carried out for different radiator ram air speeds. The results show that by adjusting the flow rates according to certain variables, the overall effectiveness of the cooling system can be increased and hence overheating problems can be minimized. A solution is proposed for improving the cooling system by employing an epicyclic gear train to vary the speeds thereby to vary the coolant flow rates in accordance to the coolant temperature.

Department of Design and Automation

SAE Technical Paper Series

Cooling System Optimisation of a Multi - Point Fuel Injection Engine

Polyacrilonitrile (PAN)/ Polyvinylfloride (PVDF) blends were modified by loading the graphene (0.5 to 1.5 wt %). The presence of graphene reveals the interesting surface properties. The decrease in surface roughness as function of graphene loading was confirmed by the topographic method of recording (two and three dimensional images) with atomic force microscope (AFM). The blends become smoother in nature due to occupied smaller surface area of graphene. This property may be useful for several applications in the marine, naval, nuclear domain and engineering applications as barrier medium.

AIP Conf Proc

Optimized surface topography of thermoplastics blends modified by graphene

<a href="https://www.sciencedirect.com/topics/engineering/engine-management-system">Engine management systems</a> (EMS) has become an essential component of a <a href="https://www.sciencedirect.com/topics/engineering/spark-ignition">spark ignition</a> (SI) engine in order to achieve high performance; low fuel consumption and low exhaust emissions. An engine management system (EMS) is a mixed-signal embedded system interacting with the engine through number of sensors and actuators. In addition, it includes an engine control algorithm in the control unit. The control strategies in EMS are intended for <a href="https://www.sciencedirect.com/topics/engineering/air-to-fuel-ratio">air-to-fuel ratio</a> control, ignition control, electronic throttle control, <a href="https://www.sciencedirect.com/topics/engineering/idle-speed-control">idle speed control</a>, etc. Hence, the control system architecture of an EMS consists of many sub-control modules in its structural design to provide an effective output from the engine. Superior output from the engine is attained by the effective design and implementation of the control system in EMS. The design of an engine control system is a very challenging task because of the complexity of the functions involved. This paper consolidates an overview of the vital developments within the SI engine control system strategies and reviews about some of the basic control modules in the engine management system.

Annual Reviews in Control

A review on control system architecture of a SI engine management system

This study proposes the preliminary simulation of a single cylinder spark ignition engine with waste heat recovery system. To harvest waste heat energy from the engine exhaust a thermoelectric generator coupled to a vapor absorption refrigeration (VAR) system was proposed in this simulation work. Parametric simulation of engine, thermoelectric generator and VAR using thermodynamic relations was carried out in MATLAB – Simulink software. An attempt has been made mathematically to integrate engine, thermoelectric generator and VAR system to study the effect of engine load, speed, equivalence ratio on thermoelectric output and coefficient of performance (COP) of a VAR system. In this study, the VAR system runs by taking heat energy from the exhaust gas and the electric power produced by a thermoelectric generator was utilized to run the pump of the refrigeration system. It was found that COP of the absorption refrigeration system depends on engine load, speed and air fuel equivalence ratio. The study also reveals that about 10% to 15% of the total exhaust energy can be harvested using this system.

Heat Transfer-Asian Research

Theoretical Investigation of Waste Heat Recovery from an IC Engine Using Vapor Absorption Refrigeration System and Thermoelectric Converter

The engine, which uses both conventional diesel fuel and LPG fuel, is referred to as ‘LPG–diesel dual fuel engines’. LPG dual fuel engines are modified diesel engines which use primary fuel as LPG and secondary fuel as diesel. LPG dual fuel engines have a good thermal efficiency at high output but the performance is less during part load conditions due to the poor utilization of charges. This problem can be overcome by varying factors such as pilot fuel quantity, injection timing, composition of the gaseous fuel and intake charge conditions, for improving the performance, combustion and emissions of dual fuel engines. This article reviews about the research work done by the researchers in order to improve the performance, combustion and emission parameters of a LPG–diesel dual fuel engines. From the studies it is shown that the use of LPG in diesel engine is one of the capable methods to reduce the PM and NOx emissions but at same time at part load condition there is a drop in efficiency and power output with respect to diesel operation.

Fulltext

Alexandria Engineering Journal

LPG diesel dual fuel engine – A critical review

The consumption of energy is increasing in exponentially due to increase in population and quality of living. Most of the energy is obtained from fossil fuels by polluting the atmosphere and thereby all living creatures. Hence there is one common goal to reduce the pollution from internal combustion engines. New technologies that use renewable sources such as solar, wind etc are being developed. Since development will take some time to realize in large scale, a cost effective method have been introduced by using gaseous fuel such as methane, hydrogen, LPG as primary fuel conventional diesel as pilot fuel. Dual Fuel Engine is found to reduce pollution such as NOx, soot, HC and power output doesn't change largely. It is found that the time required for the fuel to combust in this engine is longer than in diesel engine due to the fact that flame has to propagate from diesel to primary fuel. Also it is found that the combustion timing can be reduced if the air fuel mixture is homogeneously mixed. Hence we conducted a CFD(Computational Fluid Dynamics) study for comparing the mixing characteristics of air fuel mixture between various injector orientations at 0°,45°,135° with natural induction using venturi with one and two holes for LPG induction. The CFD results shows us that the naturally aspirated LPG induction using venturi with two holes gives us more homogeneous mixture of air and LPG than any injectors at constant rpm.

Journal of Chemical and Pharmaceutical Sciences

A comparative study of port injected and carbureted type LPG-diesel dual fuel engine using CFD analysis

Reduction of emission from the engine is a very difficult task these days since emission norms are becoming very strict on NOx, HC, CO etc. Special methods should be incorporated into the engines to have such emission standards. Here dual fuel diesel engine which use liquefied petroleum gas (LPG) and diesel fuel is suggested for better HC values in the emission. Proposed system uses a Fuzzy logic based controller to control the LPG flow into the engine and diesel as a pilot fuel which is only used to ignite the fuel. Also, EGR system will reduce the NOx content in the exhaust. Both EGR and LPG are controlled by a fuzzy closed loop control system.

Variation of gaseous fuel flow rate in a dual-fuel diesel engine using fuzzy logic

The need of energy is increasing enormously day by day and presently it is being fulfilled mostly by depleting energy resources like coal and petroleum based fuels. This situation pushes mankind to search for novel green technologies which can convert efficiently even low grade heat energy into useful energy. Thermoelectric generator (TEG) promises to be clear technology to generate electricity. TEG uses temperature gradient between source and sink to generate electricity. In this study, performance of commercially available thermoelectric module was studied using a specially designed cross flow heat exchanger. The heat exchanger was optimized previously using commercially available CFD package Ansys CFX. The efficiency of thermoelectric module was calculated by taking figure of merit and Carnot efficiency into consideration. The results indicate that the commercially available TEG used in this study, which is made of Bismuth Telluride performs efficiently at higher temperature difference and value of figure of merit is around one at maximum efficiency.

Advanced Materials Research

Performance Analysis of Single Module Thermoelectric Generator

To meet the present requirements of the automotive industry, there is continuous search to improve the performance, exhaust emission, and life of the IC engines. The meet the first two challenges, researchers are working both on newer engine technologies and fuels. Some of the published work indicates that coating on the combustion surface of the engine with ceramic material results in improved performance and reduced emission levels when fueled with alternate fuel blended fuels, and this serves as a base for this work. Normal-Butanol has molecular structure that is adaptable to gasoline, and it is considered as one of the alternative fuels for SI engines. Blending <a href="https://www.sciencedirect.com/topics/engineering/butanol">butanol</a> with gasoline changes the properties of the fuel and alters the engine <a href="https://www.sciencedirect.com/topics/engineering/performance-and-emissions">performance and emission</a> characteristics. This is because heat which is released at a rate as a result of combustion of the compressed air–fuel mixture in the <a href="https://www.sciencedirect.com/topics/engineering/combustion-chamber">combustion chamber</a> gets changed with respect to change fuel properties, <a href="https://www.sciencedirect.com/topics/engineering/air-fuel-ratio">air fuel ratio</a>, and engine speed. An experimental investigation is carried out on a partially insulated single cylinder SI engine to study the performance and emission characteristics when fueled with two different blends of butanol and gasoline. The cylinder head surface and valves are coated with a ceramic material consisting of <a href="https://www.sciencedirect.com/topics/engineering/zirconium">Zirconium</a> dioxide (ZrO2) with 8% by weight of <a href="https://www.sciencedirect.com/topics/engineering/yttrium-oxide">Yttrium Oxide</a> (Y2O3) to a thickness of 0.3&nbsp;mm by plasma spray method. Two different fuel blends containing 10% and 15% by volume of butanol in Gasoline are tested on an <a href="https://www.sciencedirect.com/topics/engineering/engine-dynamometer">engine dynamometer</a> using the uncoated and ceramic coated engines. The results strongly indicate that combination of ceramic coated engine and butanol gasoline blended fuel has potential to improve the engine performance.

Study of performance and emission characteristics of a partially coated LHR SI engine blended with n-butanol and gasoline

The objective of the present work is to partially insulate the combustion chamber of an SI engine using two different ceramic materials and investigate its effect on engine performance and exhaust emissions. Two different ceramic materials, namely, alumina (Al2O3) and partially stabilised zirconia (ZrO2), were used separately to create thermal insulation on the cylinder head to a thickness of 300 μm. The engine was fuelled with 15% ethanol–85% gasoline blend (E15). The experimental results of alumina and zirconia coated engine were compared with baseline unmodified engine. The results show that both the partially insulated engines improve brake thermal efficiency and reduce exhaust emission. Around 20% reduction in hydrocarbon and 23% reduction in carbon monoxide emission from baseline values were achieved at part loads. However, ∼30% increase in NOx emission was observed at higher loads in partially insulated engines. Significant changes in performance and exhaust emission between alumina and zirconia coated engine were not noticed.

Journal of the Energy Institute

Experimental investigation on low heat rejection SI engine fuelled with E15

In internal combustion engines, the concept of low heat rejection (LHR) using thermal barrier coating on the surface of combustion chamber is gaining attention. Thermal barrier coating reduces the heat transfer to the cooling system, protects engine components from peak heat flux and fluctuating temperature produced during combustion and improves the performance of the engine. Information in the literature is plentiful for LHR diesel engine and only few studies exist on LHR spark ignited engine. The application of thermal barrier coating in spark ignited engine is limited by pre-ignition and knocking due to elevated combustion chamber temperature. A spark ignited engine with moderate insulation on the combustion chamber and higher octane fuel can overcome this difficulty. The objective of the present experimental study is to quantify the changes in performance and emission characteristics brought by partial thermal insulation on the combustion chamber of a four stroke spark ignited engine fueled with E20 blend. Partial thermal insulation was created by coating 0.3 mm thick Alumina (Al2O3) on the cylinder head, inlet and exhaust valves. The changes are quantified with respect to unmodified engine fueled with gasoline. The combustion parameters such as flame development and rapid burn duration are also estimated and compared. The results indicate that partially insulated SI engine when fueled with E20 improves performance and reduces emission. A maximum of 48% reduction in THC and 50% reduction in CO emission at part load was achieved.

Journal of Mechanical Science and Technology

Performance and emission characteristics of a low heat rejection spark ignited engine fuelled with E20

This paper deals with experimental investigation of swirling flow in the cylinder of a spark ignited engine. The variations in different non-dimensional parameters such as Flow Coefficient, Swirl Coefficient and Swirl Ratio at various valve lifts and throttle opening was studied using a steady flow bench. The swirl enhancement using valve shrouding, and twisted tape insert was also investigated. The results indicate that a higher swirl coefficient and swirl ratio can be achieved with shrouded valve and twisted tape with penalty on flow coefficient. These experimental results can be utilized to verify the results of modeling using commercial CFD codes and also for increasing the accuracy of mathematical modeling of combustion process in internal combustion engines. © 2006-2012 Asian Research Publishing Network (ARPN).

ARPN Journal of Engineering and Applied Sciences

Investigation of flow during intake stroke of a single cylinder internal combustion engine

A major part of the heat supplied in an internal combustion engine is not realized as work output, but dumped into the atmosphere as waste heat. If this waste heat energy is tapped and converted into usable energy, the overall efficiency of AN engine can be improved. The percentage of energy rejected to the environment through exhaust gas which can be potentially recovered is approximately 30-40% of the energy supplied by the fuel depending on engine load. Thermoelectric modules which are used as thermoelectric generators are solid state devices that are used to convert thermal energy from a temperature gradient to electrical energy and it works on basic principle of Seebeck effect. This paper demonstrates the potential of thermoelectric generation. A detailed experimental work was carried to study the performance of thermoelectric generators under various engine operating conditions. A heat exchanger with 18 thermoelectric generator modules was designed and tested in the engine test rig. Thermoelectric modules were selected according to the temperature difference between exhaust gases side and the engine coolant side. Various designs of the heat exchangers were modeled using computer aided design and analysis was done using a computational fluid dynamics code which is commercially available to study the flow and heat transfer characteristics. From the simulated results it was found that rectangular shaped heat exchanger met our requirements and also satisfied the space and weight constraint. A rectangular heat exchanger was fabricated and the thermo electric modules were incorporated on the heat exchanger for performance analysis. The study also revealed that energy can be tapped efficiently from the engine exhaust and in near future thermoelectric generators can reduce the size of the alternator or eliminate them in automobiles.