Emission Control

liberation Control Techniques 1. INTRODUCTION The indispensability to subordination the figure outs from automobiles gave rise to the in traffic patternation processing establishmentization of the automobile. Hydrocarbons, carbon monoxide and oxides of nitrogen argon put up rised during the bring downing process and argon emitted into the atmosphere from the tail pipe. thither argon prodigally hydrocarbons emitted as a result of desiccationization of shove alongoline and from the crankcase of the automobile. The loose circulate acquit of 1977 set limits as to the amount of to each one of these pollutants that could be emitted from an automobile.The manufacturers settlement was the addition of certain pollution tell devices and the creation of a self- determineing locomotive. 1981 power saw the first of these self-adjusting railway locomotives. They were called feedback sack control corpses. An oxygen sensor was installed in the boot out organisation and w ould measure the open fire content of the free stream. It then would ravish a signal to a microprocessor, which would analyze the reading and purpose a burn mixture or striving mixture device to render the proper standard atmosphere/ give the axe ratio.As computer systems progressed, they were able to adjust ignition spark timing as well as operate the another(prenominal) procession controls that were installed on the fomite. The computer is also pileusable of supervise and diagnosing itself. If a fault is seen, the computer leave alert the vehicle operator by illuminating a malfunction indicator lamp. The computer leave alone at the same time record the fault in its memory, so that a technician can at a later insure retrieve that fault in the form of a code which will foster them determine the proper rep halo.Some of the more popular dismission control devices installed on the automobile are EGR valve, Catalytic Converter, Air Pump, PCV Valve, Charcol Canitiser and so forthteratera Like SI railway locomotive CI engines are also major seeded player of sacking. Several experiments and technologies are developed and a lot of experiments are going on to s vex dismissal from CI engine. The main constituents causation diesel motor liberation are smoke, soot, oxides of nitrogen, hydrocarbons, carbon monoxides etc. Unlike SI engine, emission progress tod by carbon monoxide and hydrocarbon in CI engine is small.Inorder to give better engine performance the emission must be curb to a great extend. The emission can be centralised by using smoke suppressant additives, using particulate matter traps, SCR ( discriminating Catalytic Reduction) etc. 2. sacking halt IN SI ENGINE 2. 1. Methods to reduce emission in SI engine. 2. 1. 1. Catalytic Converter Automotive emissions are controlled in three ways, one is to promote more complete burning at the stake so that there are less by products. The second is to reintroduce excessive hydrocar bons back into the engine for flame and the third is to support an additional world for oxidation or conflagration to occur.This additional area is called a catalytic convertor. The catalytic convertor looks like a muffler. It is located in the exhaust system ahead of the muffler. Inside the convertor are pellets or a honeycomb do of platinum or palladium. The platinum or palladiums are apply as a catalyst (a catalyst is a marrow utilize to induce up a chemical process). As hydrocarbons or carbon monoxide in the exhaust are passed over the catalyst, it is chemically oxidized or converted to carbon dioxide and water. As the convertor works to clean the exhaust, it develops heat.The dirtier the exhaust, the life-threateninger the converter works and the more heat that is developed. In some cases the converter can be seen to glow from excessive heat. If the converter works this hard to clean a dirty exhaust it will destroy itself. as well leaded give the sack will pu t a coating on the platinum or palladium and render the converter in telling. 2. 1. 2. PCV Valve The purpose of the positivistic crankcase ventilation (PCV) system, is to take the vapors produced in the crankcase during the normal combustion process, and redirecting them into the seam/ furnish inhalant system to be burned during combustion.These vapors misdirect the atmosphere/ open fire mixture, they baffle to be carefully controlled and metered so as non to affect the performance of the engine. This is the job of the positive crankcase ventilation (PCV) valve. At easy, when the air/ go off mixture is really critical, just a pocket-size of the vapors are allowed in to the use of goods and services system. At naughty velocity when the mixture is less critical and the squeezes in the engine are greater, more of the vapors are allowed in to the recess system. When the valve or the system is clogged, vapors will back up into the air filter housing or at worst, the excess pressure will push past seals and create engine oil leaks.If the wrong valve is employ or the system has air leaks, the engine will idle rough, or at worst engine oil will be sucked out of the engine. 2. 1. 3. EGR Valve The purpose of the exhaust petrol recirculation valve (EGR) valve is to meter a small amount of exhaust gas into the intake system this dilutes the air/fuel mixture so as to frown the combustion chamber temperature. Excessive combustion chamber temperature creates oxides of nitrogen, which is a major pollutant. While the EGR valve is the most effective method of controlling oxides of nitrogen, in its very design it adversely affects engine performance.The engine was not designed to run on exhaust gas. For this reason the amount of exhaust entering the intake system has to be carefully monitored and controlled. This is accomplished by dint of a serial publication of electrical and vacuum switches and the vehicle computer. Since EGR action reduces performance by d iluting the air /fuel mixture, the system does not allow EGR action when the engine is stone-cold or when the engine needs full power. pic Fig. 2. 4. EGR Valve 2. 1. 4. Evaporative Controls shoot a lineoline evaporates sort of easily. In the past these evaporative emissions were vented into the atmosphere. 0% of all HC emissions from the automobile are from the gas tank. In 1970 order was passed, prohibiting venting of gas tank fumes into the atmosphere. An evaporative control system was developed to eliminate this source of pollution. The function of the fuel evaporative control system is to trap and parentage evaporative emissions from the gas tank and carburetor. A charcoal canister is used to trap the fuel vapors. The fuel vapors adhere to the charcoal, until the engine is started, and engine vacuum can be used to draw the vapors into the engine, so that they can be burned along with the fuel/air mixture.This system requires the use of a sealed gas tank filler cap. This c ap is so important to the operation of the system, that a testify of the cap is at a time being integrated into many state emission inspection programs. Pre-1970 cars released fuel vapors into the atmosphere through the use of a vented gas cap. Today with the use of sealed caps, redesigned gas tanks are used. The tank has to have the space for the vapors to collect so that they can then be vented to the charcoal canister. A purge valve is used to control the vapor flow into the engine. The purge valve is operated by engine vacuum.One common some(prenominal)er with this system is that the purge valve goes bad and engine vacuum draws fuel instanter into the intake system. This enriches the fuel mixture and will foul the spark plugs. most charcoal canisters have a filter that should be put backd periodically. This system should be checked when fuel mileage drops. 2. 1. 5. Air Injection Since no inwrought combustion engine is 100% efficient, there will always be some unburned fue l in the exhaust. This profits hydrocarbon emissions. To eliminate this source of emissions an air injectant system was created. Combustion requires fuel, oxygen and heat.Without any one of the three combustion cannot occur. Inside the exhaust intricate there is sufficient heat to digest combustion, if we introduce some oxygen than any unburned fuel will ignite. This combustion will not produce any power, but it will reduce excessive hydrocarbon emissions. Unlike in the combustion chamber, this combustion is uncontrolled, so if the fuel content of the exhaust is excessive, explosions that sound like popping will occur. There are times when under normal conditions, such as deceleration, when the fuel content is excessive. Under these conditions we would want to shut off the air shooting system.This is accomplished through the use of a diverter valve, which instead of shutting the air pump off diverts the air away from the exhaust manifold. Since all of this is do after the comb ustion process is complete, this is one emission control that has no effect on engine performance. The only maintenance that is required is a careful inspection of the air pump drive belt. 2. 2. Modification in SI engine to reduce emission. Multi-port fuel guess system to all counterchange carburetors. Electronic engine management to accurately regulate fuel supply to cylinders by sensing non-homogeneous engine parameters. 4-valve system to replace 2-valve system, improved combustion chamber design and improved inlet manifold design for axial stratification of charge. Turbo-charged (TC) and Turbo-charged After Cooled (TCAC) engines. Turbo-compounded engines they are found to be upto 18 per cent better than the conventional engines. After treatment, catalytic converter and exhaust gas recycling. Some future directions for engines are Lean burn technology, air-fuel ratio as lean as 221 is practicable with 4-valves, extravagantly swirl and squish generated turbulence. Use of ceramic components (e. g. low minginess Silicon Nitride, Si3N4) such as piston pins, valves, blades in turbochargers. variant Valve energizing (VVA) providing improved charge control of SI engines, reducing fuel pulmonary tuberculosis by 5 per cent at low/medium speed and13 per cent at full engine speed. 3. EMISSION CONTROL IN CI ENGINE 3. 1. Methods to reduce emission in CI engine 3. 1. 1 Particulate filter. Particulate filters are highly effective in the elimination of particulate matter (PM10) or soot from diesel exhaust. It has a variety of filter coatings and designs, depending of the engine application and duty calendar method. . 1. 2. Selective catalytic reduction Selective Catalytic Reduction of dark (generally minify with SCR deNOx) is a very powerful technology to reduce the NOx emission and fuel habit of truck and passenger car diesel engines. The European truck manufacturers starting in October 2005, when EURO-4 emissions legislation enters into force, will introduce SCR deNOx on a large scale. With SCR deNOx a 32. 5% aqueous urea settlement is injected upstream of the catalyst. Urea which converts to NH3 (ammonia) in the hot exhaust gases reacts with NOx to form harmless N2 and H2O.The urea quantity needs to be precisely treat as a function of the engine NOx output and the catalyst operating conditions. 3. 1. 3. Smoke Suppressant additives There are a fare of additives, which are added in order to reduce the smoke from CI engine. HYDRAX ATH (hydrated alumina), HYDRAMAX (magnesium hydroxides and hydroxy-carbonates), CHARMAX LS (low smoke), CHARMAX LS ZST & LS ZHS (atomic number 30 stannates & zinc hydroxystannates), CHARMAX AOM & MO (ammonium octamolybdate & molybdic oxide), CHARMAX ZB200 & ZB400 (zinc, magnesium, and calcium borates) etc.This reduces the amount of smoke produced by various chemical reactions. The smoke produced can also be controlled by deairating, maintenance, catalytic mufflers, fumigation etc. 3. 1. 4. Control o f odor It is very difficult to estimate the odour produced by the diesel engine because the lack of standard tests has not allowed overmuch work to be done in this direction. Catalytic odour control system muffler and or catalyst container are under growth and it has been found that certain oxidation catalysts if used under favorable conditions reduce odour intensity.But the tests are still going on. 3. 1. 5. Exhaust Gas and After treatment Modeling While the diesel (compression ignition) engine is more efficient than the conventional spark ignition engine from a thermodynamics standpoint, it has the capability for a large negative milieual impact. The lean combustion of these devices provides the correct environment for the production of NOx relatively high temperatures and abundant oxygen. In addition, direct injection of fuel into the combustion chamber creates rich fuel pockets that can cause the formation of particulate matter (soot).Recently these emissions have come und er increased scrutiny from the Environmental Protection theatrical performance (EPA). Their radical nature (smog) in the atmosphere and subsequent health hazards has caused the EPA to act to increase the regulation standards for both 2007 and 2010. Unlike the three-way catalysts shortly used on spark-ignition based platforms, diesel after treatment systems will not utilize one device for all problematic emissions. Instead, devices are targeted to take care of only one or a few issues at a time.For instance, Diesel Particulate Filters (DPF) might take care of the particulate matter while a Diesel Oxidation Catalyst (DOC) will eliminate the CO and HC and a Lean NOx Trap is used for the NOx emissions. Until now, diesel engine manufacturers have been able to meet the legislation though in-cylinder technology. The proposed EPA legislation has caused the diesel industry to work on purpose cost-efficient after treatment technology while still facial expression in-cylinder for improvement s. 3. 2. Modification in CI engine to reduce emission 3. 2. 1. commercial message vehicle emission controlSeveral improvements are needed. These could be achieved through redesigning of engines and application of new technologies Improvement in fuel injection system and use of higher injection pressure. . . gross rail system unit of measurement injections instead of multi-cylinder fuel injection pumps. Electronically controlled injection system to provide variable injection timing with good dynamic response to engine load, speed, and temperature. Improved cylinder head design, inlet port, re-entrant combustion chambers. 4-Valve system to improve volumetric efficiency and provide better mixing of fuel and air. Turbo-charged and Turbo-charged aftercooled engines to provide higher specific power, better fuel economy, and less emission pollution. After-treatment, particulate traps, and catalytic converters. 3. 2. 2. Passenger Car Diesel Engine In India, Indirect Injection (IDI) diesel engines are commonly used in passenger cars. Due to the pricing policies of fuels, the running cost of diesel cars is disappoint than those of petrol cars. Diesel engines are popular for taxis, most of which are retrofitted by diesel engines. Private cars with OE diesel engines are also in demand. major directions for engine ontogenesis to control different pollutants are as follows HC emission control requires, low sac volume nozzles Complete combustion of injected fuel minimum lube ingestion. NOx emission control is helped by, cooling of intake air before entering the engine Retarded combustion and incorporate air motion. Particulate emission control is helped by, high injection pressure fine fuel atomization intensive air motion high excess air and minimum lube consumption. 4. EMISSION CONTROL NORMS IN SI AND CI ENGINEThe first Indian emission regulations were idle emission limits which became effective in 1989. These idle emission regulations were soon r eplaced by mass emission limits for both gasoline (1991) and diesel (1992) vehicles, which were gradually tightened during the 1990s. Since the socio-economic class 2000, India started adopting European emission and fuel regulations for four-wheeled light-duty and for heavy-duty vehicles. Indian own emission regulations still apply to two- and three-wheeled vehicles. 4. 1. Emission control norms in SI engine. slacken. 4. 1 EMISSION CONTROL NORMS IN SI ENGINE level of Emission 2/3 Wheelers 4 Wheelers Norms 2-Stroke 4-Stroke 4-Stroke * Intake, exhaust, * Intake, exhaust, combustion optimization * 4-Stroke engine combustion optimization Euro I /India 2000 * Catalytic converter technology *Carburetor optimization * Secondary air injection * calefactory tube * open fire njection Euro II / * Catalytic converter * Secondary air * Catalytic converter Bharat gift II * CNG / LPG injection * Fixed EGR (3 wheelers only) * CNG / LPG * Multi-valve (3 wheelers only) * CNG/LPG * Fuel injection +catalytic * Fuel injection * Fuel injection converter * Catalytic converter * Carburetor+ * Variable EGR EuroIII/ Bharat story catalytic converter * Variable valve timing III * Multi-valve * On-board diagnostics system * CNG/LPG * Direct cylinder Euro IV / * To be developed * Lean burn injection Bharat tip IV * Fuel injection+ * Multi-brick catalytic converter catalytic converter * On-board diagnostics system Euro norms are not applicable for 2 / 3 wheelers in India 4. 2. Emission control norms in CI engine Level Of Emission Norms Technology Options Retarded injection timing Open/re-entrant bowl, Euro I / India 2000 Intake, exhaust and combustion optimisation FIP700-800 bar, low sac injectors elevated swirl Naturally aspirated Turbocharging Injection pressure 800 bar, moderate swirl spicy pressure inline / rotary pumps, injection rate control Euro II / VO nozzles Bharat stand for II Re-entrant combustion chamber Lube oil consumption control Inter-cooling (optional, depends on specific power), EGR (may be required for high speed car engines) Conversion to CNG with catalytic converter Multi valve, Low swirl high injection pressure 120 bar Rotary pumps, pilot injection rate shaping Electronic fuel injection Euro III / slender lube oil consumption control Bharat Stage III Variable geometry turbocharger (VGT) Inter-cooling Oxycat & EGR CNG/LPG High specific power output Particulate trap NOx trap On board Diagnostics system Euro IV / Common rail injection-injection pressure1600 bar Bharat Stage IV Fuel Cell CNG/LPG On October 6, 2003, the national Auto Fuel polity has been announced, which envisages a phased program for introducing Euro 2 4 emission and fuel regulations by 2010. The implementation schedule of EU emission standards in India is summarized in Table 4. 3 The above standards apply to all new 4-wheel vehicles change and registered in the respective regions.In addition, the discipline Auto Fuel Policy introduces certain emission requirements for interstate buses with routes originating or terminating in Delhi or the other 10 cities. For 2-and 3-wheelers, Bharat Stage II (Euro 2) is be applicable from April 1, 2005 and Stage III (Euro 3) standards would come in force p signifyably from April 1, 2008, but not later than April 1, 2010. Table. 4. 3. INDIAN EMISSION STANDARDS Indian Emission Standards (4-Wheel Vehicles) Standard Reference Date Region India 2000 Euro 1 2000 Nationwide Bharat Stage II Euro 2 2001 NCR*, Mumbai, Kolkata, Chennai 2003-04 NCR*, 10 Cities 2004-05 Nationwide Bharat Stage III Euro 3 2005-04 NCR*, 10 Cities 2004-10 Nationwide Bharat StageIV Euro 4 2010-04 NCR*, 10 Cities * National Capital Region (Delhi) Mumbai, Kolkata, Chennai, Bangalore, Hyderabad, Ahmedabad, Pune, Surat, Kanpur and Agra Th e above standards apply to all new 4-wheel vehicles sold and registered in the respective regions. In addition, the National Auto Fuel Policy introduces certain emission requirements for interstate buses with routes originating or terminating in Delhi or the other 10 cities. For 2-and 3-wheelers, Bharat Stage II (Euro 2) will be applicable from April 1, 2005 and Stage III (Euro 3) standards would come in force preferably from April 1, 2008, but not later than April 1, 2010. Emission standards for new heavy-duty diesel enginesapplicable to vehicles of GVW 3,500 kgare listed in Table 4. 4. Emissions are tested over the ECE R49 13-mode test (through the Euro II stage). Table 4. 4 EMISSION STANDARDS FOR DIESEL TRUCK AND wad ENGINES, G/KWH stratum Emission standards for light-duty diesel vehicles (GVW ? 3,500 kg) are summarized in Table 3. Ranges of emission limits refer to different classes (by reference mass) of light commercial vehicles compare the EU light-duty vehicle emissio n standards page for lucubrate on the Euro 1 and later standards. The lowest limit in each range applies to passenger cars (GVW ? 2,500 kg up to 6 seats). Table 4. EMISSION STANDARDS FOR LIGHT-DUTY DIESEL VEHICLES, G/KM Year The test cycle has been the ECE + EUDC for low power vehicles (with maximum speed limited to 90 km/h). Before 2000, emissions were measured over an Indian test cycle. Engines for use in light-duty vehicles can be also emission tested using an engine dynamometer. The respective emission standards are listed in Table 4. 3 Table 4. 6 EMISSION STANDARDS FOR LIGHT-DUTY DIESEL ENGINES, G/KWH Year Emission standards for gasoline vehicles (GVW ? ,500 kg) are summarized in Table 5. Ranges of emission limits refer to different classes of light commercial vehicles (compare the EU light-duty vehicle emission standards page). The lowest limit in each range applies to passenger cars (GVW ? 2,500 kg up to 6 seats). Table 4. 7 EMISSION STANDARDS FOR GASOLINE VEHICLE S (GVW ? 3,500 KG), G/KM Year Reference CO HC HC+NOx 1991 - 14. 3-27. 2. 0-2. 9 - 1996 - 8. 68-12. 4 - 3. 00-4. 36 1998* - 4. 34-6. 20 - 1. 50-2. 18 2000 Euro 1 2. 72-6. 90 - 0. 97-1. 70 2005 Euro 2 2. 2-5. 0 - 0. 5-0. 7 * for catalytic converter fitted vehicles earlier introduction in selected regions, see Table 4. Gasoline vehicles must also meet an evaporative (SHED) limit of 2 g/test (effective 2000). Emission standards for 3- and 2-wheel gasoline vehicles are listed in the following tables. Table 4. 8 EMISSION STANDARDS FOR 3-WHEEL GASOLINE VEHICLES, G/KM Year CO HC HC+NOx 1991 12-30 8-12 - 1996 6. 5 - 5. 40 2000 4. 00 - 2. 00 Table 4. 9 EMISSION STANDARDS FOR 2-WHEEL GASOLINE VEHICLES, G/KM Year CO HC HC+NOx 1991 12-30 8-12 - 1996 4. 0 - 3. 60 2000 2. 00 - 2. 00 CONCLUSION Efforts are being made to reduce the consumption of fossil fuels and maximize the utilization of environment-friendly energy sources and fuels for run across energy needs. In India, the demand for oil for the transport sector is estimated to increase over the next decade. This sector is the largest consumer of petroleum products . Government is providing policy support, fiscal incentives and regulatory measures for development of alternative energy vehicles and fuels.Battery operated vehicles, fuel cellular phone vehicles, hydrogen provide vehicles and bio-fuel powered vehicles have been identified in this context. The development activities of such fuels and vehicles need to be further encouraged particularly in view of their potential to protect the environment. Hybrid Electric Vehicles (HEVs) use the junto of engine of a conventional vehicle with electric motor powered by traction batteries and/or fuel cell. This combination helps in achieving both the energy and environmental goals. The deployment of a large number of this type of vehicles would help us in terms of environmental benefits, reduction of oil consumption and reduction in emissions. In crow n of thorns electric vehicles propulsion, energy is lendable from more than one source of energy.The three configurations of HEV are series hybrid system, parallel hybrid system and split hybrid system. Fuel cells produce electricity, employing reaction between hydrogen and oxygen gases, electrochemically. Fuel cells are efficient, environmentally benign, compact, modular and reliable for power generation. Different type of Fuel cells currently under development are the Protons Exchange Membrane Fuel Cells (PEMFCs), phosphorous Acid Fuel Cells (PAFCs), Molten Carbonate Fuel Cells (MCFCs),Solid Oxide Fuel Cells (SOFCs) etc. Hydrogen is receiving worldwide attention as a clean fuel and efficient energy storage medium for automobiles. Hydrogen can replace or supplement oil used in road transportation.Bio-fuel is an efficient, environment friendly, 100 per cent natural energy alternative to petroleum fuels9-10. In view of the potential of being produced from several agricultural sourc es and because of its low emission characteristics, bio-fuels in recent years are receiving a great chew of attention as a substitute to petroleum fuels. Ethanol and bio-diesel are the two bio-fuels which are being looked upon as the potential fuels for surface transportation. REFERENCES 1. www. howstuffworks. com 2. www. dieselnet. in 3. www. auto101. com 4. www. wikipedia. com 5. Mathur & Sharma. Internal Combustion Engine, Dhanpat rai publications. pp 774- 778 1. SEMINAR TOPIC FROM www. edufive. com/seminartopics. html