technology to meet new emission norms

Presentation on “ Technologies to meet Bharat Stage III and

IV emission legislations on Automotive Vehicles ”

1Preet Ferozepuria

Contents

1. Introduction to Automotive Emission 2.Emission Norms: BS III & IV (Passenger Car and Commercial vehicles) 3.Technology Available

2.1 Commercials Vehicles for BS III2.1.1 Rotary pumps2.1.2 Diesel Oxycat (DOC) 2.1.3 Turbochargers2.1.4 EGR

2.2 Commercial Vehicles for BS IV2.2.1 Common rail2.2.2 EGR

3. Passenger Vehicles3.1 Diesel

3.1.1 Advantages of Diesel Passenger vehicles3.1.2 Available technologies for BS III norms3.1.3 Technologies for BS IV norms3.1.4 Technologies for BS V norms

3.2 Gasoline

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Thermochemistry of fuel-air mixture

Gas ppm by Volume

Molecular Weight

Mole Fraction

Molar Ratio

O2 2,09,500 31.998 0.2095 1N2 7,80,900 28.012 0.7905 3.773Ar 9,300 38.948

CO2 300 40.009Air 10,00,000 28.962 1 4.773

PRINCIPLE CONSTITUENTS OF DRY AIR

• O2 is the reactive component in air.

• Air (O2 -21% and N2 -79%)

• For 1 mole of O2 there is 3.773 moles of N2

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Gasoline or Petrol Diesel CNG LPG

Ehanol

Alcoholes

Biofuels

I.C. Engine Fuels

Petrol and diesel are blend of different hydrocarbon compounds obtained byrefining crude oil

Petrol: General formula : CnH1.87n

C8.26H15.5 to C7.76H13.1

LHVP = 44, 000 KJ/Kg, mol. wt. ≅ 110

Diesel: General formula : CnH1.8n

C10.8H18.7

LHVP = 42500 KJ/Kg, mol. wt. ≅ 148.6S’ up to 1%, 4Preet Ferozepuria

CNG (Compressed Natural Gas) – Mainly Methane. RON is higher, therefore, can run at higher C.R. as compared to Gasoline. Thus, more efficient engine.

LPG (Liquefied Petroleum Gas) – Mixture of Propane and Butane. Note: Butane content is higher in domestic LPG, which can cause gumming

inside the engine, thus not recommended for Automotive purpose.

E10 Fuel: With 10% ethyl alcohol derived from sugarcane added ingasoline.

B10 Fuel: With 10% diesel supplements, for example, ‘Jatropha’ oil beingadded into diesel. The fuel injection manufacturers like BOSCH allow up to10% blending to safeguard against warranty of Fuel Injection components.

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Combustion Stoichiometry

Complete combustion (Oxidation) when sufficient oxygen is available.The carbon in the fuel is converted to CO2 and Hydrogen to H2O.C3H8(propane) + 5O2 = 3CO2 + 4H2OComplete combustion (oxidation) of general hydrocarbons in air at lowtemperature, when N2 is non reactive:CaHb + (a+b/4)(O2+3.773N2)=aCO2 +b/2H2O+3.773(a+b/4) N2Above equation defines, Stoichiometric or chemically correct ortheoretical proportion of fuel and air; i.e. there is just enough oxygenfor conversion of all the fuel into completely oxidized products.(Stoichiometric combustion occur when all the oxygen is consumed inthe reaction & there is no molecular oxygen(O2) in the product)

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The stoichiometric air/fuel ratio depends upon fuel composition.(A/F)s = (1+y/4)(32+3.773 x 28.16) = 34.56(y+4)

12.011+1.008y 12.011+1.008yWhen y=b/a for fuel composition written as CHywhere molecular weight of O2,atmospheric N2, atomic carbon andatomic hydrogen are respectively ,32, 28.16,12.011 and 1.008(A/F)s depends on y only i.e.(A/F)s diesel = 34.56(1.73 + 4) = 198.03 = 14.4

12.011 + 1.008 x 1.73 13.75(A/F)s petrol = 14.5 For gasoline/diesel as fuel, as it is a mixture of hydrocarbons a & bare not integers.

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For diesel taking C10.8H18.7 as average donation , molecular weight will be;Mdiesel = 12.011a + 1.008b

= 12.011 x 10.8 + 1.008 X 18.7 = 148.6 For octane C8H18, at (A/F)s = 34.56(4+2.25) = 216 =15.13

12.011+1.008 x 2.25 14.279the complete combustion is as per below equation(FUEL) + (AIR) = (PRODUCTS)C8H18 + 12.5 (O2 + 3.773 N2) = 8CO2+9H2O + 47.16N2

At 25% excess air then the stoichiometric or fuel-lean combustion, theextra air appears in the product in unchanged form.C8H18 + 1.25 x12.5(O2 + 3.773N2) = 8CO2 + 9H2O + 58.95N2 + 3.13O2

With less than the stoichiometric air requirement, i.e., with fuel-richcombustion, there would be insufficient oxygen to oxidize fully C and H toCO2 & 3H2O with CO appearing in the products.

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The ratio of actual A/F ratio to stiochiometric A/F ratio is importantparameter for defining mixture composition.

λ = (A/F)actual/ (A/F)sFor lean mixture: λ > 1For Rich mixture: λ < 1For stiochiometric mixture: λ = 1For SI engines 0.8 < λ < 1.2; For diesel engines 1.3 < λ < 5.0In SI engine, the air mass flow rate is being changed through a venturiwhile maintaining λ in close range. This results into very highpumping losses under part load causing poor overall efficiency.The diesel engine runs at about same air flow rate while fuelquantity is being varied form 1.3 : 5. Therefore, pumping lossesare small and diesel engine runs more efficiently on leanmixture. Therefore, CO produced is significantly less ascompared to an SI engine.

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For alcohols, the fuel oxygen is included in the oxygenbalance between reactants and products.For ethyl alcohol(ethanol) C2H5OH, thestoichiometric combustion equation is:C2H5OH + 3(O2+3.773N2) = 2CO2 + 3H2O +11.32N2

(A/F)s= 9.00NOTE: At normal combustion temperaturesignificant dissociation of CO2 and H2O occurs &NO and NO2 is generated.

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2.5

1.5

0.00

0.50

1.00

1.50

2.00

2.50

3.00

Petrol Diesel

Cos

t of R

unni

ng /

km(R

s/K

m)

B-Segement carsDiesel -IDI

15% further advantage by DI

BENEFITS OF DIESEL FUEL ENGINES

1. Fuel-efficient by 30 %

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2. Subsidy by Government on Diesel Fuel • Diesel prices less by 30% in India • Diesel prices 16% less in Europe

Petrol ~ 40.5 Rs/Lts

Diesel ~ 30.0 Rs/Lts

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Engine R.P.M 2000, Both Engines Euro II compliant

11 11.1 11.3 11.6

3.65

6.37.4

0

2

4

6

8

10

12

14

25 50 75 100LOAD

% C

O 2 E

MISS

ION

COMP

ARIS

ION

CNG

V/S

DI

ESEL

ENG

INE

CNG EngineDiesel Engine

3. Less CO2 emission By 2008, new vehicles legislated to meet limit of 140g/km in Europe.

The CO2, which is a greenhouse effect gas, emitted far less by diesel engine as compared to Petrol and CNG engines equipped with TWCs (Three Way Catalysts).

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CO2 Reduction Roadmap for Passenger cars 165 165 -1% Vehicle Weight Reduction by 2% g/km

-3% Reduce losses (Aerodynamic, lubricants, rolling 160 resistance, powertrain friction)

-2% Diesel Penetration by 50%

155 -0.7% Gasoline DI Penetration by 7%

150 -1.3% ‘VVA’ penetration by 15% 145 -3.5% 5-10% ENGINE DOWNSIZING

-2% CVT & DCT penetration by 25% 140 -1% Mild Hybrid penetration by 5%

140 g/km

2001 2008 Further CO2 Reduction: -20% by 2012 -30% by 2016

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At normal combustion temperature and reaction rates, significantdissociation of CO2 occurs to generate CO; NO and NO2 is generated formAtmospheric N2.

Actual Combustion Products

(Cn Hp+S) + O2 CO2 + H2O

DIESEL FUEL +

+HC CONOX PM

SO2 +SO3

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DIESEL ENGINE EMISSION

NOX HCPM CO CO2

VISIBLEPOLLUTANT--SMOKE

LEGISLATED

TO BELEGISLATED

GASEOUS POLLUTANTS

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EMISSION NORMS: BS III & IV

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BHARAT STAGE-III EMISSION NORMS FOR PASSENGER VEHICLES (Cars & SUVs/MUVs)

18

Category byReference Mass (RW), kg

CO (g/km)

HC+NOx (g/km)

NOx (g/km)

PM (g/km)

(Up to 6 occupants) orRW≤1305 kg

0.64 0.56 0.50 0.05

RW between 1305-1760 kg 0.80 0.72 0.65 0.07

RW >1760 kg 0.95 0.86 0.78 0.10

DIESEL ENGINE

Reference Mass of vehicle: Kerb Weight + 150 kg

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DIESEL ENGINE


CO (g/km)

HC+NOx (g/km)

NOx (g/km)

PM (g/km)


0.50 0.30 0.25 0.025

RW between 1305-1760 kg 0.63 0.39 0.33 0.04

RW >1760 kg 0.74 0.46 0.39 0.06

BHARAT STAGE-IV EMISSION NORMS FOR PASSENGER VEHICLES (Cars & SUVs/MUVs)

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GASOLINE ENGINE


CO (g/km)

HC(g/km)

NOx(g/km)


2.3 0.20 0.15

RW between 1305-1760 kg 4.17 0.25 0.18

RW >1760 kg 5.22 0.29 0.21

BHARAT STAGE-III EMISSION NORMS FOR PASSENGER VEHICLES (Cars & SUVs/MUVs)

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GASOLINE ENGINE


CO (g/km)

HC(g/km)

NOx (g/km)


1.0 0.1 0.08

RW between 1305-1760 kg 1.81 0.13 0.10

RW >1760 kg 2.27 0.16 0.11

BHARAT STAGE-IV EMISSION NORMS FOR PASSENGER VEHICLES (Cars & SUVs/MUVs)

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Deterioration Factor Deterioration factor (DF) as given in below Table is the margin,

which is applied on emission norm values so that over the life of vehicle emission is not exceeded.

Engine Category

Deterioration Factor

CO HC NOx HC+NOx

PM

Gasoline Engines

1.2 1.2 1.2 Not Applicable

Diesel Engines

1.1 N.A. 1.0 1.0 1.2

Alternatively, the vehicle manufacturer may opt for an ageing test of 80, 000 km for evaluating deterioration factor.

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TECHNOLOGY AVAILABLE

COMMERCIALS VEHICLES FOR BS III

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MECHANICALLY-CONTROLLED DISTRIBUTOR PUMPS (VE)

1 Fuel tank2 Fuel filter, 3 Distributor fuel-

injection pump,4 Nozzle holder with

nozzle, 5 Fuel return line, 6 Sheathed-element

glow plug (GSK)7 Battery, 8 Glow-plug and

starter switch, 9 Glow control unit

(GZS).

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FUEL-INJECTION TECHNIQUES

• Small high-speed diesel engines demand a lightweight and compact fuel-injection installation. The VE distributor fuel-injection pump fulfills these stipulations by combining – Fuel-supply pump, – High-pressure pump, – Governor, and – Timing device,

Fields of application

Fig.: VE distributor pump fitted to a 4-cylinder diesel engine

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The subassemblies and their functions

1 Vane-type fuel-supply pump withpressure regulating valve: Draws in fueland generates pressure inside thepump.

2 High-pressure pump with distributor:Generates injection pressure, deliversand distributes fuel.

3 Mechanical (flyweight) governor:Controls the pump speed and variesthe delivery quantity within the controlrange.

4 Electromagnetic fuel shutoff valve:Interrupts the fuel supply.

5 Timing device: Adjusts the start ofdelivery (port closing) as a function ofthe pump speed and in part as afunction of the load.

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Design and construction

1 Pressure-control valve, 2 Governor assembly, 3 Overflow restriction, 4 Distributor head with high-

pressure pump,5 Vane-type fuel-supply pump,6 Timing device, 7 Cam plate,8 Electromagnetic shutoff

valve.

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Fuel supply and delivery

• It delivers a virtually constant flowof fuel per revolution to the interiorof the injection pump.

• Using this valve, it is possible toset a defined pressure for a givenspeed.

Components1 Drive shaft,2 Pressure-control valve,3 Eccentric ring,4 Support ring,5 Governor drive,6 Drive-shaft dogs,7 Overflow restriction,8 Pump housing.

Low-pressure delivery

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Fuel tank

Requirements:• The fuel tank must be of non-corroding material, and must remain

free of leaks at double the operating pressure at 0.3 bar.• Suitable openings or safety valves must be provided,• Fuel must not leak past the filler cap or through pressure

compensation devices.• The fuel tank and the engine must be so far apart from each other

that in case of an accident there is no danger of fire.


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Fuel lines

Requirements:• An alternative to steel pipes, flame-inhibiting, steel-braid-armored

flexible fuel lines can be used for the low-pressure stage• These must be routed to ensure that they cannot be damaged

mechanically, and• They cannot be damaged fuel which has dripped or evaporated

must not be able to accumulate nor must it be able to ignite.


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Fuel Filter

• The injection pump’s high-pressure stage and the injection nozzleare manufactured with accuracies of several thousandths of amillimeter.

• Fuel filter specifically aligned to the requirements of the fuel-injectionsystem is absolutely imperative if trouble-free operation and a longservice life are to be achieved.


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Vane-type fuel supply pump

• The vane-type pump islocated around theinjection pump’sdriveshaft.

• Its impeller isconcentric with theshaft and connected toit with a Woodruff keyand runs inside aneccentric ring mountedin the pump housing.


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Pressure-control valve• The pressure-control valve is

connected through a passage tothe upper (outlet) kidney-shapedrecess, and is mounted in theimmediate vicinity of the fuel-supply pump.

• If fuel pressure increasesbeyond a given value, the valvespool opens the return passageso that the fuel can flow back tothe supply pump’s suction side.


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Overflow restriction

• The overflow restriction isscrewed into the injectionpump’s governor cover andconnected to the Pump’sinterior.

• It permits a variable amountof fuel to return to the fueltank through a narrowpassage


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Delivery valve

• The delivery valve closesoff the high-pressure linefrom the pump.

• It has the job of relievingthe pressure in the line byremoving a definedvolume of fuel uponcompletion of the deliveryphase

• The delivery valve is aplunger-type valve. It isopened by the injectionpres-sure and closed by itsreturn spring.

High-pressure delivery

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Constant-pressure Valve with return-flow restriction (RSD)

• To prevent such harmfulreflections, the delivery valve isprovided with a restriction borewhich is only effective in thedirection of return flow.

• This return-flow restrictioncomprises a valve plate and apressure spring so arranged thatthe restriction is ineffective in thedelivery direction, whereas in thereturn direction damping comesinto effect.


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Constant-pressure valve (GDV)

• constant-pressure valvesare fitted which relieve thehigh-pressure system(injection line and nozzleand holder assembly) bymeans of a single-actingnon-return valve which canbe set to a givenpressure,(e.g., 60 bar).


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High-pressure stage

• The fuel pressure needed for fuel injection is generated in the injection Pump’s high-pressure stage.

• The pressurized fuel then travels to the injection nozzles through the delivery valves and the fuel-injection tubing.

Fuel supply and delivery

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Distributor-plunger drive

• The distributor plunger isheld in the cam plate by itscylindrical fitting piece and islocked into position relativeto the cam plate by a pin.

• The distributor plunger isforced upwards to its TDCposition by the cams on thecam plate, and the twosymmetrically arrangedplunger-return springs forceit back down again to itsBDC position.

High-pressure stage

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Cam plates and cam contours

• The cam plate and its cam contour influence the fuel-injection pressure and the injection duration, whereby cam stroke and plunger-lift velocity are the decisive criteria.

• the different combustion-chamber configurations and combustion systems used in the various engine types, the fuel-injection factors are individually tailored to each other.

High-pressure stage

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Distributor headGenerates the high pressureand distributes the fuel to therespective fuel injector.1 Yoke, 2 Roller ring, 3 Cam plate, 4 Distributor-plunger foot, 5 Distributor plunger, 6 Link element,7 Control collar,8 Distributor-head flange,9 Delivery-valve holder, 10 Plunger-return spring,4 8 Distributor head.

High-pressure stage

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Fuel metering

• The fuel delivery from afuel-injection pump is adynamic processcomprising several strokephases

• The cam plate rotatesagainst the roller ring,whereby its cam trackfollows the rollers causing itto lift (for TDC) and dropback again (for BDC)

High-pressure stage

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Distributor plunger with stroke and delivery phases

High-pressure stage

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MANIFOLD – PRESSURE COMPENSATOR (LDA)

- A turbocharger forces pressurized fresher air into the intake tract. This charge–air pressure allows a diesel engine of any given displacement to generatemore power and torque than its atmospheric – induction counterpart in anygiven speed band.

- Fuel delivery by the pump is adapted to suit the increase density of this aircharge to get effective Power increase.

- During part load operation when cylinder charge density is relatively low, fueldelivery is reduced so as not to result into higher visible smoke. This functionis carried out by Manifold – Pressure Compensator (LDA), which is mountedon top of a distributor pump (also possible on inline pump).

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• The interior of the LDA isdivided into two separateairtight chambers by adiaphragm to whichpressure is applied by aspring.

• The diaphragm isconnected to the LDA’ssliding pin which has ataper in the form of acontrol cone.


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Method of operation• In the lower engine-speed range the

charge-air pressure generated by theexhaust turbocharger and applied to thediaphragm is insufficient to overcome thepressure of the spring.

• As soon as the charge-air pressure applied tothe diaphragm becomes effective, thediaphragm, and with it the sliding pin andcontrol cone, shift against the force of thespring.

• Should the turbocharger fail, the LDA revertsto its initial position and the engine operatesnormally without developing smoke


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LFB- LOAD DEPENDENT TIMING ADVANCE

FUNCTION

- As the diesel engine’s load factor changes , the start of injection must be advanced orretarded accordingly.

- The load – sensitive start of delivery is designed to react to declining loads (from full –load to part throttle) by retarding start of delivery and responds to rising load factors byshifting the start of delivery towards advancing. This adaptive process providessmoother engine operation along with cleaner emissions at part throttle and idle.

NOTE: The LFB can be deactivated to reduce HC emissions generated by the dieselengine when it is cold (<60˚c).

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Design and construction• For load-dependent

injection timing,modifications must bemade to the governor shaft,sliding sleeve, and pumpdevices housing.

• The sliding sleeve isprovided with an additionalcutoff port, and thegovernor shaft with a ring-shaped groove, alongitudinal passage andtwo transverse passages .


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Method of operation

• As a result of the rise in thesupply-pump pressure whenthe engine speed increases,the timing device adjusts thestart of delivery in the advancedirection.

• The control lever is used toinput a given full-load Speed.


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KSB- Cold Start injection Advance

- The cold – start compensation device improves the diesel engine’scold – start response by advancing the start of delivery.

- This feature is controlled by an automatic temperature – sensitivecontrol device which take input from coolant and / or ambienttemperature.

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• The KSB is attached to thepump housing, the stop leverbeing connected through ashaft to the inner lever onwhich a ball pin iseccentrically mounted.

• The automatic advancemechanism is mounted onthe distributor pump, where-as the manual operatingmechanism is in the driver’scab.


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Method of operation

• Automatically and manually operated cold-start accelerators (KSB) differ only with regard to their external advance mechanisms.

• KSB is triggered by the driver from the cab (timing-device KSB), independent of the advance defined by the timing device (a), an advance of approx. 2.5camshaft is maintained (b)


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ATMOSPHERIC – PRESSURE SENSITIVE FULL LOAD STOP (ADA)

- Owing to the lower air density , the mass of inducted air decreases at highaltitudes.

- If the standard fuel quantity prescribed for full – load operation is injected ,there will not be enough air to support full combustion. The immediate resultsare smoke generation and rising engine temperatures .

- The atmospheric pressure –sensitive full – load stop can help prevent thiscondition.

- It varies full – load fuel delivery in response to changes in barometricpressure .

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• The construction of the ADA isidentical to that of the LDA. Theonly difference being that theADA is equipped with ananeroid capsule which isconnected to a vacuum systemsomewhere in the vehicle (e.g.,the power-assisted brakesystem). The aneroid provides aconstant reference pressure of700mbar (absolute).


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Method of operation

• Atmospheric pressure is applied to the upper side of the ADAdiaphragm. The a reference pressure (held constant by the aneroidcapsule) is applied to the diaphragm’s underside.

• If the atmospheric pressure drops (for instance when the vehicle isdriven in the mountains), the sliding bolt shifts vertically away fromthe lower stop and, similar to the LDA, the reverse lever causes theinjected fuel quantity to be reduced.


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SOLENOID-VALVE-CONTROLLED AXIAL-PISTON DISTRIBUTOR FUEL-INJECTION PUMPS (VE-MV)

• This pump is of modular design. The field- proven distributor injectionpump can thus be combined with a new electronically controlled fuel-metering system.

• The most important new components are:1. Angle-of-rotation sensor which is located in the injection pump on the driveshaft

between the vane-type supply pump and the roller ring,2. Electronic pump ECU, which is mounted as a compact unit on the top side of the

pump and connected to the engine ECU,3. High-pressure solenoid valve, installed in the center of the distributor head.

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• The distributor head and the openedhigh-pressure solenoid valve, thevane-type supply pump delivers fuelto the high-pressure chamber at apressure of approx. 12 bar.

• No fuel is delivered when the high-pressure solenoid valve is de-energized (open).

• The valve’s instant of closing definesthe injection pump’s start of delivery.

• Similarly, the valve’s instant ofopening defines the pump‘s end ofdelivery.

METHOD OF OPERATION

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DIESEL OXIDATION CATALYSTS (DOC)

• Flow through oxidation catalyst (two-way catalytic convertor) forreduction of CO and VOF (80%), and PM SOF (20-30%). Doesnot retain PM.

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• To increase performance increase the inlet density.– Done by manifold tuning or

forced induction.

• Pack more air into cylinders.

• Typical boost of 6 to 8 psi provided.

• Significantly raise horsepower without significant weight gain.

BASICS OF TURBOCHARGERS

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WHY IT IS EFFECTIVE

Through the use of forced induction, turbochargers compress the air entering the engine causing it to be extremely dense; with more air in a small area, more gasoline can be coupled with the air creating larger explosions in the cylinder which help the car to progress forward

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Turbocharger DesignProcess of the air flow:

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BENEFITS OF TC ON ENGINE PERFORMANCE

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• More specific power over naturally aspirated engine. This means aturbocharged engine can achieve more power from same engine volume.

• Better thermal efficiency over both naturally aspirated and superchargedengine when under full load (i.e. on boost). This is because the excessexhaust heat and pressure, which would normally be wasted, contributessome of the work required to compress the air.

• Weight/Packaging. Smaller and lighter than alternative forced inductionsystems and may be more easily fitted in an engine bay.

• Fuel Economy. Although adding a turbocharger itself does not save fuel, itwill allow a vehicle to use a smaller engine while achieving power levels of amuch larger engine, while attaining near normal fuel economy while offboost/cruising. This is because without boost, less fuel is used to create aproper air/fuel ratio.

BENEFITS OF TC ON ENGINE PERFORMANCE

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• Air density and pressure decrease• 1/2 as much air at 20,000 feet as at sea level• Less oxygen

NOTE: Temperature and exhaust back pressure are decreasing but this is not enough tooffset the decline in density and pressure

Problems of Altitude

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How Turbocharger helps

• More fuel and air at a higherpressure can produce morehorsepower within an engine

• A naturally aspirated engine canonly burn as much fuel as it has airto mix with

• Mechanical aspiration increases thedensity of the air in the inductionmanifold so that more fuel can beadded

• Mechanical aspiration increases thepressure in the combustion chamberto increase power

• The increases in power are limitedby the strength, temperature, andlubrication limits in the engine

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Turbine Compressor Intercooler Tachometer and Boost

Gauge Wastegate Bearings

DETAILING SPECIFIC PARTS

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TURBINE• The exhaust flow from the engine is directed

over the blades of the turbine to provide theforce to turn the shaft and compressor

• Leaks in the exhaust system before theturbine will decrease performance

• Combustion deposits may form on the turbineand reduce efficiency

• Turbine speed is controlled to change theamount of boost available

• Proper mounting and connection between theturbine and turbine shaft is necessarybecause it operates at such high speeds.

• The Wastegate releases excess exhaustwaste from the turbine.

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Turbine TechnologyMain Parts

1. Turbine rotor2. Turbine nozzle Ring3. Turbine casing

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1.Turbine Rotor Blades are forged of

Nimoinic alloy It is connected with rotor

shaft by means of frictionwelding.

Blades are fastened toturbine disk by means offir-tree foot connection.

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2. Turbine nozzle Ring

Nozzle Ring casing is insulatedwith simple and high efficientmaterial to reduce thetemperature and Noise.

With improved flow in nozzlering, Reduce the Vibrationacceleration of rotor blade andimproved stability of nozzle ring.

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3. Turbine Casing

• A turbine casing for enclosing a gas turbine component, such as a fan, a compressor, a combustion chamber or a turbine.

• The suction-side opening forms an outlet-flow opening for the medium

• The pressure-side opening forms an inlet-flow opening.

• Applications of the turbine casing are particularly suitable both for high-pressure turbines and for medium-pressure turbines

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• When the compressor wheel spins, it draws in air from the ambient air inletlocated on the opposite side of the turbine exhaust gas inlet to retrieve coolair.

• The compressor increases the density of incoming air by six to eightpounds per square inch (psi).

• At sea level, the density of air is 14.7 psi, so the compressor yields about afifty percent increase (Nice).

• The highly compressed air leaves the compressor section through thecompressor air discharge as it travels towards the intercooler.

COMPRESSOR

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Compressor TechnologyMain parts:

1. Compressor wheel (inducer & impeller)2. Compressor silencer-air filter3. Air intake casing4. Compressor outlet casing

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Compressor wheel (inducer & impeller)

• It is made up of a single piece high-strength aluminum alloy andtitanium for compression ratio 4.5 and to withstand up to 560 m/scircumferential velocity.

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Compressor silencer-air filter

• Air intake silencer housings can be useful for silencing objectionable air intake noise and providing protection for air compressors.

• An intake silencer for attenuatingintake air noise, and being disposedto fluidly connect said air filter boxwith an air intake port of saidcompressor .

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Air intake casing

• It is either constructed with 90degree bent or as an axial air inletduct

• The larger flow paths and wide-curved deflection regions exhibitsconstant pressure and velocitydistribution at compressor inlet.

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Compressor outlet casing

• Having wide flow sections and large outlet areas.

• It convert kinetic energy into pressure energy.

Note: In large propulsion engine (Chargeabove 4.0 bars), Compressorcasing can be heat insulated

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TRIM• Trim is a term to express the relationship between the inducer and exducer

of both turbine and compressor wheels.

•The inducer diameter is defined as the diameter where the air enters the wheel, •whereas the exducer diameter is defined as the diameter where the air exits the wheel.

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A/R(Area/Radius) Ratio

• It is defined as the inlet (or, for compressorhousings, the discharge) cross-sectionalarea divided by the radius from the turbocenterline to the centroid of that area

• Compressor A/R Larger A/R housings are used for low boost

applications. Smaller A/R are used for high boost applications.

• Turbine A/R Smaller A/R will increase the exhaust gas velocity

into the turbine wheel Larger A/R will decrease the exhaust gas velocity

into the turbine wheel

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VARIABLE GEOMETRY TURBOCHARGER (VGT)

• A Variable Geometry turbocharger is also known as a variable Turbine geometry turbocharger (VTGT), or a Variable Nozzle Turbine (VNT).

• usually designed to allow the effective aspect ratio(sometimes called A/R Ratio) of the turbo to be altered as conditions change.

• The vanes are controlled by a membrane actuator identical to that of a Wastegate, although electric servo actuated vanes are becoming more common.

WHY : Big turbocharger do not work well at slow engine speeds, while small turbocharger are fast to spool but run out of steam pretty quick. But VTG turbocharger solve this problem

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VARIABLE GEOMETRY TURBOCHARGER WORKING

In this cut-through diagram, The direction ofexhaust flow when the variable vanes are in analmost closed angle. The narrow passage of whichthe exhaust gas has to flow through acceleratesthe exhaust gas towards the turbine blades,making them spin faster.

This cut-through diagram shows the exhaust gasflow when the variable turbine vanes are fullyopen. The high exhaust flow at high engine speedsare fully directed onto the turbine blades by thevariable vanes.

A turbocharger equipped with Variable TurbineGeometry has little movable vanes which can directexhaust flow onto the turbine blades. The vaneangles are adjusted via an actuator. The angle of thevanes vary throughout the engine RPM range tooptimize turbine behavior.

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EGR (EXHAUST GAS RE-CIRCULATION)

Concept : exhaust –gas recirculation (EGR) is highly effective measure for NOx emissions on diesel engines.

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- Reduction in fresh intake air mass going into cylinder as it isreplaced with inert exhaust gases.

-This results in drop in rate of combustion and thus leads intoreduction of peak temperature.

Reduction in local excess – air factor.

- At part load with higher EGR rates, almost homogeneous mixtureconditions are achieved resulting into extremely low – NOx and low –particulate combustion.

EGR IS EFFECTIVE MAINLY DUE TO :

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WORKING OF EGR

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ON/OFF EGR USING VALVE :-Solenoid operated on/off EGRvalue

-Value put on intake side for longerlife

-On/off status to be decided by-Position of accelerator lever of fuelinjection pump

-Usually valve is switched at 80 -90 % offull travel of accelerator

-A micro – switch or a throttleposition sensor (TPS) used tosignal On/ Off position

-Around 10-20 % NOx reductionpossible under steady statetesting.

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MAPPED / PROPORTIONATE EGR:

- Very high rates of EGR flows possible (upto 30% at part loadconditions).

- Possible reduction of NOx by 50%.

- Exhaust flow still driven by differential pressure between exhaustand intake.

- Requires higher exhaust back pressures .This drawback can beovercome by having an intake throttle.

- Costlier equipment .

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The EGR system is having a control valve which is controlled by theelectronic control unit (ECU).The ECU output to control EGR valvedepends on the three inputs:1. Throttle Position: Throttle position is sensed by the throttle

position sensor(TPS), which is mounted on the accelerator leverof on FI pump or throttle paddle in the cabin.

2. Water Temperature: Water temperature sensor is mounted onthe water out let of the engine.

3. R.P.M: R.P.M is sensed by the magnetic r.p.m sensor which ismounted on the bell housing of the flywheel.

ECU AND SENSORS FOR EGR

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EGR OPERATION

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TECHNOLOGY AVAILABLE COMMERCIALS VEHICLES FOR BS IV

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MULTIPLE INJECTION COMMON RAIL SYSTEM

• Common-rail (accumulator) fuel-injection systems make it possibleto integrate the injection system together with a number of itsextended functions in the diesel engine.

• It thus increase the degree of freedom available for defining thecombustion process.

• The common-rail system's principal feature is that injection pressureis independent of engine speed and injected fuel quantity.

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COMMON RAIL SYSTEM

Major reductions in NOx and particulate matter emissions.Main characteristics of common rail fuel injection system, which give it advantage over other

systems lies in.- Injection pressure is independent of engine speed (RPM)

(Therefore PM is controlled at all speeds)- Injection begin and injection duration can be freely selected. Split injections up to 5 per cycle

possible.- Low drive torque.

Benefits of Common Rail Diesel Injection system:

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MULTIPLE INJECTIONS IN A CR SYSTEM

Upto 6 part injection events are possible with common rail system as shown below.

1. Early pilot injection for torque increase at low speed and noise control.2. Close pilot injection for emissions and noise control.3. Main injection.4. Close post injection for NOx/Soot Control.5. Late post injection for control of λ < 1 operation.6. Very late post injection for HC-enrichment or exhaust gas temperature increase.

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SENSORS

The sensors A to F are as follows:A. Crankshaft position;B. Camshaft position; C . Accelerator pedal; D. Boost pressure; E. Air temperature;F. Coolant temperature

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• The functions of pressure generation and injection are separated by an accumulator volume.

• The pressure is generated bya high-pressure plunger pump

• An in-line pump is used in trucks and a radial-piston pump in passenger cars.

• This injector serves as thecore of this concept byensuring correct fuel delivery into the combustion chamber

System design

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Hydraulic performance potential

• This system enhances the latitude for defining combustion-processpatterns by separating the pressurization and injection functions.

• The pressures currently used are 1350 bar in passenger-carsystems and 1400 bar in commercial-vehicle systems.

• Pilot injection and multiple injection can be used to further reduceexhaust and particularly noise emissions.

• The system can trigger the extremely fast solenoid several times insuccession for multiple injection.

• Hydraulic pressure is used to augment injector-needle closing,ensuring rapid termination of the injection process.

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System application engineering on the engine

• No major modifications are required to adapt the diesel engine foroperation with the common-rail system.

• A high-pressure pump replaces the injection pump, while theinjector is integrated in the cylinder head in the same manner as aconventional nozzle-and-holder assembly.

• All of these features make the common-rail configuration yet anotherinjection-system option.

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COMMON-RAIL SYSTEM GENERATIONS

• Bosch’s third generation 3.2 system, due next year, will give 1800-bar injectionpressures, while 3.3 version, set for SOP in 2007, will yield 2000 bar pressure.Emission levels up to Euro 5 standards may be achieved without the need forNOx-reduction measures.

• The fourth generation system using novel HADI (Hydraulically Assisted DieselInjector) due in 2008 will deliver pressures to an unprecedented 2500 bar.

• Denso, the world’s number – three component maker, claims that the company’s1800 bar CRDi system, with its five injections per cycle, gives such cleancombustion that DPF is unnecessary to meet EURO 4 norms.

• I generation CR: Pressure Upto 1350 bar• II generation CR: Pressure Upto 1600 bar

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COMMON RAIL TYPE FUEL INJECTION PUMP –ELECTRONIC CONTROL

The ECU controls fuel delivery timing and amount99Preet Ferozepuria

PASSENGER VEHICLESDIESEL ENGINE

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ADVANTAGES OF CI ENGINE OVER SI ENGINE

• A diesel engine is much more efficient than a gasoline engine.A common margin is 40% more miles per gallon for anefficient turbodiesel.

• A diesel engine does not require an ignition system due to theheat generated by the higher compression,

• A diesel engine has a better fuel economy due to the completeburning of the fuel, and

• A diesel engine develops greater torque due to the powerdeveloped from the high-compression ratio.


• Engines are durable and if properly cared for will maintain theireconomy.

• Can use a variety of fuels and mixtures• Exhaust gases produced by diesel engine are less poisonous

i.e. contain less amount of carbon monoxide• Fuel used in diesel engine is less volatile that means there is

no vapor lock problems in diesel engine.

ADVANTAGES OF CI ENGINE OVER SI ENGINE


TORQUE ADVANTAGE OF THE CI ENGINES RELATIVE TO SI ENGINES

• The result of the higher torque of the diesel engine is thatdiesel engine-powered vehicles require a lower power- to-weight ratio than vehicles using gasoline engines.


Fuel Economy - Acceleration Correlations for Gasoline and Diesel Engine Vehicles


FUEL PRICE CHART


GROWTH OF DIESEL VEHICLES


TECHNOLOGY AVAILABLE

COMMERCIALS VEHICLES FOR BS III


Gasoline Engines


Training ContentStandard systems of fuel injection in SI engines

1. Carburettor system for Gasoline, CNG & LPG Engines Open loop system Close loop system

2. Throttle body systemPetrol Injection In throttle body systemGas Injection in throttle body system

3. Multi point fuel injection system or Intake –manifold injection (External A/F mixture formation)

4. Gasoline Direct Injection (GDI) system


• A carburetor, is a device, that blends air and fuel for an internalcombustion engine.

• The throttle (accelerator) linkage does not directly control the flowof liquid fuel. Instead, it meters the flow of air being pulled into theengine.

• The carburetor works on Bernoulli's principle: the faster air movesin the venturi during acceleration requirements, higher isits dynamic pressure and lower its static differential pressure w.r.tatmosphere. This higher pressure differential pulls more fuel forhigher total charge flow requirements during acceleration.

CARBURETOR SYSTEM


CARBURETTOR SYSTEM


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• The closed-loop system reliably controls the Air/Fuel ratio naturalgas (CNG) or propane (LPG) engines at all operating conditions toStoichiometric.

• This reduces tail pipe emissions and fuel consumption.• Included are the electronic control module, a high-resolution stepper

motor gas flow metering valve and a wiring loom.• Feedback from original or retrofit throttle position sensor (TPS), or

manifold absolute pressure sensor (MAP), as well as an exhaustoxygen sensor (Lambda Sensor) is all that is needed to provide theperformance needed to keep the A/F ratio to EU levels.(high efficiency catalytic converter is needed).

LAMBDA CLOSE LOOP SYSTEM


• It is also Called Manifold Injection or Single Point Injection (SPI) orIndirect Injection.

• The throttle body injection (TBI) system uses one or twoinjector valves mounted in a throttle body assembly.

• The injectors spray fuel into the top of the throttle body air hornThe TBI fuel spray mixes with the air flowing through the air horn.

• The throttle body injection assembly typically consists of thefollowing: throttle body housing, fuel injectors, fuel pressureregulator, throttle positioner (solenoid or stepper motor) , throttleposition sensor.

THROTTLE BODY SYSTEM


• Injector Usually Upstream FromThrottle (Air Intake Side) or In SomeCases Placed on the Opposite Side

• Pressures are Low – 2 to 6 Bar. MaybeInjected Irrespective of Intake Process

• Has Same Air and Fuel Mixing andDistribution Problems as Carburetor butWithout Venturi Restriction so GivesHigher Engine Volumetric Efficiency

• Higher Injection Pressures Comparedto Carburetion – Speeds up Atomizationof Liquid Fuel

PETROL INJECTION IN THROTTLE BODY SYSTEM


System similar to gasoline injection, but injector is of differentdesign.

GAS INJECTION IN THROTTLE BODY SYSTEM


• It also Called Port Injection or Indirect Multipoint Injection (IMPI) orSemi-direct Injection .

• In this system, Fuel reaches a rail from which Electronic Injectors,positioned in each Induction Manifold Branch Just in Front of InletPort, inject fuel at a pressure of 2-6 bar. The injectors are activatedindividually for each induction pipe where it is Mixed and StoredUntil IVO or after the valve has just opened.

MULTI POINT FUEL INJECTION SYSTEM


Stage(4)Stage(3)

Stage(1) Stage(2)


1. More uniform A/F mixture will be supplied to each cylinder, hence the difference in power developed in each cylinder is minimum. Vibration from the engine equipped with this system is less, due to this the life of engine components is improved.

2. No need to crank the engine twice or thrice in case of cold starting as happens in the carburetor system.

3. Immediate response, in case of sudden acceleration / deceleration.

4. Since the engine is controlled by ECM (Engine Control Module), more accurate amount of A/F mixture will be supplied and as a result complete combustion will take place. This leads to effective utilization of fuel supplied and hence low emission level.

5. Compared with carburetor engines and single-point injection systems, manifold fuel condensation is multipoint injection systems is reduced significantly resulting into less HC emission.

6. The mileage of the vehicle is also improved.

Advantage


• It is also Called Direct Multi-point Injection (DMPI) or Direct CylinderInjection

• Fuel is injected into the combustion chamber from a central fuel railunder high pressure by electronically controlled injector.

• Injection May be During Intake or Compression Process• To Compensate For Shorter Permitted Time For

Injection/Atomization/Mixing Injection Pressure Must Be Higher• Ignition is reliable as a relatively rich mixture cloud close to the spark

plug is available (Choke function not required for cold start)• Injector Nozzle Must Be Designed For Higher Pressure and

Temperature So Must Be More Robust and Will Be Costlier ThanOther Types

• Condensation and Wall Wetting in Intake Manifold eliminated ButCondensation On Piston Crown and Cylinder Walls

• The direct injection cools the interior of the cylinder from evaporationof the fuel that reduces knocking at full loads. This makes it possibleto increase C.R. by approximately one unit.

GASOLINE DIRECT INJECTION (GDI) SYSTEM


• In contrast to conventional engines with intake manifold injectionsystem which work under nearly all operating condition at ahomogenous stoichiometric mixture, the DI engine is operatedusing different injection and combustion strategies.

• Under hot engine at low and medium load conditions: The goal ofstratified charging is to concentrate a well-prepared fuel-airmixture at the spark plug so that a locally limited, ignitablemixture arises (Lambda~1). The fuel is injected late into thecompression stroke. This allows stable combustion despiteoverall engine running under lean operation with WOT forminimum pumping loss and maximum air flow.

• For same output under cold start conditions, a homogenousslightly lean mixture would burn efficiently. This is achieved byclosing the throttle valve to reduce air flow, the fuel injectedquantity is also increased and injection is done during the intakestroke itself.



Ward’s 10 Best Highlights Gasoline Direct Injection (GDI) Engines

Ward’s 10 Best Engines 2006Automaker Engine Test Vehicle

Audi 2L FSI turbocharged DOHC I-4 Audi A3

Audi 4.2L DOHC V-8 Audi S4

BMW 3L DOHC I-6 330i

DaimlerChrysler 5.7L Hemi Magnum OHV V-8 Dodge Charger R/T

Ford 4.6L SOHC V-8 Mustang GT

GM 2L supercharged DOHC I-4 Chevy Cobalt SS/td>

GM 2.8L turbocharged DOHC V-6 Saab 9-3 Aero

Mazda 2.3L DISI turbocharged DOHC I-4 Mazdaspeed 6

Nissan 3.5L DOHC V-6 Infiniti G35 6MT

Toyota 3.5L DOHC V-6 Lexus IS 350/td>


2-S Cycle

Advantages of 2S Cycle◦ Lightweight and compactness◦ Less friction losses as no oil retainer, no valve train, no oil pump◦ Low pumping losses as compared a 4S cycle◦ Double cycle frequency and high specific power output◦ NOx emission are less due to inherent internal EGR


Higher Pumping Losses in a 4-S Cycle


Low Pumping Losses in a 2-S Cycle


2S Cycle Two Major drawbacks◦ Fuel directly short-circuited in the exhaust during

scavenging causing higher fuel consumption and HCemission (Can be overcome by DI)◦ Instable combustion at part load, responsible high

fuel consumption and high unburned HC Note: As significant amount of air is directly short-

circuited and lost in the exhaust, there is excess O2 in exhaust, this has two consequences:◦ Conditions are highly favourable for HC and CO conversion

in Catcon◦ A conventional 3-way cat cannot be solution for NOx

reduction


Disadvantages of a 2-S Engine127Preet Ferozepuria

2S GDI Bajaj has introduced 3-W auto-rickshaw having

GDI in 2S. Compared to the conventional carburetted 2S model, its performance can be summarized as follows:◦ 33% better furl consumption◦ 15% more torque◦ 25% more engine performance


TECHNOLOGY AVAILABLE COMMERCIALS VEHICLES FOR BS IV


• Trap oxidizer (Diesel particulate filter), reduce PM by 95%, filter + oxidation (regeneration) functions

• The performance of the engine, as well as the consumption of fuel and the Co2 emissions similar levels to the ones of the functioning without filter are remained it.

• The escape system, that includes a pre catalysis next to the engine and a catalysis of oxidation, was conceived to reduce all the emissions of gases, in special of hydro-carbons (HC) and carbon monoxide (CO).

DIESEL PARTICULATE FILTER (DPF)


DIESEL PARTICULATE FILTER (DPF)


DIESEL OXIDATION CATALYSTS

• Flow through oxidation catalyst (two-way catalytic convertor) forreduction of CO and VOC (80%), and PM SOF (20-30%), doesnot retain PM.


TECHNOLOGY AVAILABLE COMMERCIALS VEHICLES FOR BS V


BHARAT STAGE-V NORMS FOR PASSENGERVEHICLES ENGINES

DIESEL ENGINE

Category CO (g/kWh) HC+NOx (g/kWh)

NOx (g/kWh) PM (g/kWh)

≤1305 kg0.50 0.23 0.18 0.005e

1305-1760 kg

0.63 0.295 0.235 0.005e

>1760 kg0.74 0.350 0.280 0.005e


• Ceramic materials used as a carrier (Titanium oxide)

• Active catalytic components:: oxides of base metals, zeolites &precious metals

• Base metal catalysts – lack thermal stability but inexpensive

• Zeolite catalysts – high thermal stability.

SELECTIVE CATALYTIC REDUCTION [SCR]

CATALYST


• Commonly used today are honeycomb and plate type

• Honeycomb type - smaller, - higher pressure drops, - plugging

• Plate type – larger, less susceptible to plugging, expensive.

SELECTIVE CATALYTIC REDUCTION [SCR] CATALYST GEOMETRY


technology to meet new emission norms

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