DEPARTMENT OF MECHANICALENGG: PCET BELTHANGADY A PRESENTATION OF SEMINAR ON “TRANSONIC ENGINES” Presented by: PCET ,Belthangady SAJU JOHN VIII SEM MECHANICAL USN: 4PR10ME021 TRANSONIC ENGINES Under The Guidance of Dr. Chandra Rao Madane B.E, M Tech, Ph.D, PGDMM, LMISTE, FIE Principal PCET ,Belthangady Belthangady .INTRODUCTION Internal combustion engines play a vital role in our day to day life in many ways. Efficiency and economy Efficiency. The two terms which are highly associated with an internal combustion engine are . which is simply defined by ratio of output to input . PCET . expressed in kilometers per liter(km/l). economy which is highly considered in automobile sector defined by the distance that can be travelled by the automobile by giving unit amount of fuel. used in automobiles For an SI engine where a spark plug is used for igniting the charge has lesser efficiency than a CI engine where fuel is injected by a fuel injector due to the change in compression ratio.Belhangady . As the times goes on there introduced many technologies for increasing the efficiency and economy of ac IC engine. The rapid change occurs in automobile industry as it is growing than other sectors. particularly in SI engines. Both are important for an internal combustion engine. Some of these technologies are……. PCET . Belthangady . which is developed by the transonic combustion in corporation. In TSC the fuel is directly injected to cylinder in supercritical condition PCET . Laser treatment of piston surface Advanced swirl flow induction technology (ASFS) Advanced tumble flow induction technology (ATFi) Gasoline direct injection (GDI) Programmable fuel injection (PGM-fi ) Digital twin spark ignition (DTS-I ) Digital twin spark swirl ignition (DTS-si ) Multi point fuel injection (MPFi) Laser fired engines Out of which the latest technology is transonic combustion technology (TSC). IGNITION SYSTEMS Ignition system of an SI engine is used to ignite the fuel air mixture (charge). as the gap is very small which cause the combustion PCET . It mainly consists of a spark plug which is operated at high voltage 20000-30000 V. As the piston compresses the charge then a high voltage is passed between the electrodes and a spark generates between the electrodes.1 mm).Belthangady . The spark plug consists of two electrodes which are separated at a small distance (generally 0. CONVENTIONAL SPARK IGNITION ENGINES As above explained conventional spark ignition engines uses a spark plug and mostly the systems are followed by battery ignition or the magneto ignition.Belthangady . The conventional spark ignition engines are widely used now days in light motor vehicles and especially in motorcycles PCET . The spark is produced a bit earlier than when piston reaches Top Dead Centre (TDC). e. Lead. PCET . d.Belthangady . Knocking or Detonation. Lower thermal efficiency (20-35%) under normal conditions. High exhaust emissions of (CO2 & NO2).LIMITATIONS OF CONVENTIONAL SPARK ENGINES a. this is used as an anti-knocking agent is extremely toxic to the environment. c. b. Incomplete combustion. after a short delay. results in spontaneous ignition at multiple locations. Supercritical fuel promotes rapid mixing with the contents of the cylinder which.Belthangady .TRANSONIC COMBUSTION TECHNOLOGY (SUPERCRITICAL COMBUSTION TECHNOLOGY) The Transonic Combustion system (TSC) is a new combustion process for the gasoline internal combustion engine. The TSC combustion process utilizes direct injection of fuel into the cylinder as a supercritical fluid based on the patented concept of injection-ignition. Multiple ignition sites and rapid combustion combine to result in optimum heat release and high cycle efficiency PCET . TSC has inherently short combustion delay and rapid combustion that result in heat release phasing for optimal efficiency. Such characteristics can be achieved by injecting the fuel in the form of a supercritical fluid.Direct injection of fuel in the supercritical state enables significant fuel efficiency improvements to be achieved. the combustion process must have rapid air-fuel mixing. Due to the supercritical conditions.Belthangady . In order to achieve this. It results in efficiencies that are equal to or better than today’s Diesel engines PCET .TSC brings together the injection and ignition processes to become Injection-Ignition. followed by a short delay period and combustion. gasoline ignites automatically like in diesel engines. A characteristic of the TSC combustion process is that injection of the fuel is delayed to the extent that the heat release predominantly takes place after TDC of the engine power stroke. the ability to solvate other liquids and solids. Supercritical fluids possess rapid mass transfer properties with diffusion coefficients more than ten times that of a liquid near the critical point.SUPERCRITICAL FLUID A supercritical fluid is any substance at a temperature and pressure above its critical point. . Supercritical fluids also have other unique properties such as having no surface tension. The density ranges between one third and two thirds of that of the corresponding fluid and varies significantly with temperature and pressure. Generally supercritical fluids have properties between those of a gas and a liquid. it is not a solid. liquid or a gas. CRITICAL TEMPERATURE (TC) The maximum temperature at which a gas can be converted into a liquid by an increase in pressure. CRITICAL POINT The characteristic temperature (Tc) and pressure (Pc) above which a gas cannot be liquefied. PCET .Belthangady . CRITICAL PRESSURE (PC) The minimum pressure which would suffice to liquefy a substance at its critical temperature. Belthangady .COMPONENTS OF TRANSONIC ENGINE HIGH PRESSURE PUMP CATALYTIC CONVERTER HEAT EXCHANGER SUPERCRITICAL FUEL INJECTOR PCET . PCET .HIGH PRESSURE PUMP • It pressurizes the gasoline up to 42-300 bars.It supplies the high pressurized gasoline to the catalytic converter • The high pressure pump is used to increase the pressure of gasoline above its critical pressure.Belthangady . Catalytic actions on the fuels reduce the amount of CO in exhaust emission.Belthangady . It oxidizes the fuel before the combustion by adding oxidizers like ethanol. PCET .CATALYTIC CONVERTER Metal-oxide catalyst that breaks fuel molecules down into simpler hydrocarbon chains. Catalytic activity that is two to three times of magnitude faster than the purely liquid form of the substance. It transfers heat from exhaust gaseous to the high pressure gasoline.HEAT EXCHANGER The heat exchanger increases the temperature of the gasoline above its critical temperature (280-300˚C). Thus we can use the heat energy of exhaust gaseous . It accurately measures the amount of fuel according to the load conditions which is injected to the combustion chamber The compression ratio for the transonic engine is 13.SUPERCRITICAL INJECTORS The Precision. high-speed injector whose resistance-heated pin places the fuel in a supercritical state as it enters the cylinder. Timing of fuel injection is controlled by an Electronic Controlling Unit (ECU).5:1 . OPERATION . Belthangady . The rapid mixing of the fuel enables the engine to derive maximum efficiency than in normal injection.SUPERCRITICAL INJECTION VS NORMAL INJECTION In super critical injection the fuel is readily mixed with the air than normal injection. The rapid mixing and multiple combustion sites are the reasons of the greater efficiency of transonic engines than in diesel engines PCET . ADVANTAGES OF TRANSONIC ENGINES The efficiency of gasoline engine can be increased up to 50 to 70%.Belthangady . TSC decreases the amount of fuel needed to propel a vehicle. PCET . the Transonic Combustion technology operates in gasoline engine without needing a spark plug. Convenient use of exhaust gas temperature. Like diesel engine. but will also be compatible with advanced low carbon footprint bio-fuels in the future. Transonic injection is being developed for use with gasoline engines at present. Considerable reduction in exhaust emissions. TSC technology puts it into a supercritical state that allows for very fast and clean combustion. LIMITATIONS OF TRANSONIC ENGINES Manufacturing cost is high Injectors must be made carefully PCET .Belthangady . This technology enables the use of low octane number fuels in gasoline engines. Fuel is partially oxidized by coating the fuel lines with catalytic materials like nickel & molybdenum.Belthangady .SUPERCRITICAL COMBUSTION IN DIESEL ENGINE Super critical combustion in diesel engine is achieved by heating diesel above 300°C and pressurizing it above 100 bar which is the critical temperature and pressure of diesel fuel respectively. SC combustion in diesel engine gives a thermal efficiency of 75-85% PCET . Oxygen will be supplied for this oxidation process by adding ethanol (2%) with diesel. TSC gives rapid combustion & multiple combustion sites. It injects the fuel into the combustion chamber in supercritical stage.CONCLUSION The thermal efficiency of an IC engine depends upon compression ratio. This technology can increase the economy of an IC engine. Transonic combustion technology is the latest technology used to improve the thermal efficiency of IC engine. which improve the efficiency significantly. TSC reduces the exhaust emissions PCET . quality of fuel etc.Belthangady . Belthangady KYOU .T HA N PCET .