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INDUSTRIAL ENGINEERING

____CRDi Engines____

Presented by:SIDDHARTH CHATURVEDI06105040INE

Dr. B.R. AMBEDKAR NATIONAL INSTITUTE OF TECHNOLOGY JALANDHAR

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INTRODUCTIONØ The COMMON RAIL system was developed in

late 1960`s by Robert Huber of Switzerland .

After which many refinement took place in

this field and finally , it was sold for general

purpose in 1995.

Ø the technology that has been revolutionizing

diesel engines

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ØCRDi is one of the most advanced diesel

technologies in the world, and combines both

performance and fuel economy.

ØCommon Rail Direct Injection Engine

(CRDI)WAS FIRST designed by Europian based

Detroit Diesel Company.

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ØAn advanced diesel engine technology that

improves diesel performance and emissions

level, making diesel engines on par with

comparable gasoline engines.

ØIt runs at more than 50% thermal

efficiency. It emits fewer exhaust carbons per

gallon of fuel burnt, making an eco-friendly

engine.

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Cause Of OriginThe driving motivation behind the development

of CRDi is the adherence to ever-increasing

emission regulations while maintaining the

drivability and low combustion noise

characteristics of gasoline-driven engines, and

the superior fuel economy of the diesel engine.

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What Is CRDi?

C R D I

COMMON RAIL DIRECT IGNITION

Ø The CRDi technology makes the diesel engine run like a gasoline-powered one. "It's fast, quiet and economical, while maintaining the diesel engine characteristics of higher pulling power,"

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ØIn the CRDi unit, a tube -- also called common

rail -- connects all the injectors and contains

fuel at a constant high pressure of 1800 bars.

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Direct & Indirect InjectionØIndirect Injection :- An indirect injection

diesel engine delivers fuel into a chamber off the combustion chamber, called a pre-chamber, where combustion begins and then spreads into the main combustion chamber.

This has the effect of slowing the rate of combustion, which tends to reduce audible noise. It also softens the shock of combustion and produces lower stresses on the engine components.

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ØThe addition of a pre-chamber, however, increases heat loss to the cooling system and thereby lowers engine efficiency by between 5-10% in comparison to a direct injection engine, and nearly all require some form of cold-start device such as glow plugs.

ØIndirect injection engines are cheaper to build and it is easier to produce smooth, quiet running vehicles with a simple mechanical system

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.

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Direct injection :-

Øthe Direct Injection system has the injection

nozzle actually fixed to the top of the

combustion chamber, usually the piston on

the engine with this type of injection system

has a crown shape in the top to create the

needed swirl.

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Why Direct Injection ?ØCold starting is easier.

ØMore Economical.

ØSmaller combustion space, better thermal

efficiency.

ØVERY High compression ratio is not required to

aid starting.

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Direct-Injection - BenefitsHowever, because of the big increase in

cost and complexity of a DI system, would like to get more benefits to offset system costs than just improved cold and transient engine performance and emissions.

Are there any additional benefits of a DFI system?

Yes. Increased Fuel Economy !!But, this increase in thermal efficiency

is currently possible only if the mixture-preparation state, within the cylinder, is more atomised.

`

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increased volumetric efficiency

increased compression ratio

Lean combustion

Decreased heat losses

In trying to work the above levers, DFI is an enabler with high potential. Note that advanced MPFI systems are also enablers, but with lesser potential than DFI.

Thermodynamic Levers to Increase Thermal Efficiency

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Direct-Injection – Benefits Increased Volumetric EfficiencyAirflow Characterisitics

7

7.2

7.4

7.6

7.8

8

80 120 160 200 240 280 320 360 400

End-of-Injection (°bTDC Firing)

Air

flo

w (

g/s

)

Direct-Fuel-Injection

Port-Fuel-Injection

Engine Speed = 2000 rev/min, Wide-open-throttle,Air-Fuel ratio=15:1

INTAKE STROKECOMPRESSIONSTROKE

EXHAUSTSTROKE

2.5%

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Direct-Fuel-Injection – Benefits Increased Volumetric Efficiency Direct-Fuel-Injection can result in an

increase (up to 8% has been reported)

in airflow due to spray-cooling of

the intake air, when injection occurs

during the intake stroke. The

resulting increased performance can

be converted to 1-2% increase in fuel

economy.

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Direct-Injection – BenefitsIncreased Compression RatioEffect of Compression Ratio on Otto-Cycle Thermal

Efficiency

30

35

40

45

50

55

60

65

70

2 4 6 8 10 12 14 16 18 20 22

Compression Ratio (r)

Ott

o C

yc

le E

ffic

ien

cy

, E

(%

)

Typical Compression Ratio for Port-Fuel-Injection engine

Typical Compression Ratio for Direct-Fuel-Injection engine

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Direct-Injection – BenefitsIncreased Compression RatioDirect-Fuel-Injection permits an increase

in compression ratio from 10.5 to about

12.0, resulting in about 2% increased

efficiency.

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Disadvantages of DIØHigher engine noise & vibration

ØLow thermal efficiency

ØMore polluted exhaust

ØRelatively low power

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Why CRDi?v Cut fuel consumption by 20%.

v Appox. Double torque.

v Increase power by 25%.

v Reduction in noise and vibration.

v Less pollutant exhaust.

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What is the difference?

The difference mainly lies in the fuel injection system

the fuel injection timing is electronically controlled and fuel at high pressure is available all the time and is independent of engine speed, unlike in conventional diesel engines. This results in precisely metered, quickly injected and highly atomised fuel being delivered which results in much greater overall combustion efficiency. With this greater engine efficiency and a better air and fuel mixture both in terms of quantities and mixing, a common rail engine is also much more environmentally friendly and fuel efficient.

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Technical aspect of crdi

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FeaturesØCombustion control equals or exceeds that for

a petrol engine

Øhigh fuel compression and injection pressure

are maintained.

ØFuel efficiency is improved 20%.

Ø Torque improved by 50%.

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ØPower output is improved by 25%.

ØEmission reductions are 20% for carbon

dioxide, 40% for carbon monoxide, 50% for

hydrocarbons and 60% for particulate

materials.

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Characteristics of CRDiØelectronic control over the injection time and

quantity

ØUse of "pilot" injection.

ØUse of post ignition.

ØFour to five injection per cycle.

ØHigh pressure in common rail.

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atomisation

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the combustion behaviour is affected by

1. Timing of start of injection

2. Injection duration

3. Injector discharge curve

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Company manufacturing crdi Ø Bosch

ØDelphi

ØSiemens

ØDenso

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How

Effective?

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Emision standard

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In emission, greenhouse gases (CO2) is

reduced by 20%.

At a constant level of NOx, carbon monoxide

(CO) emissions are reduced by 40%, unburnt

hydrocarbons (HC) by 50%, and particle

emissions by 60%.

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Performance

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THE CRDi ADVANTAGE

conventional engine

§ Pressures ranging from 200 - 400 bar

§Indirect injection of fuel

§Noisy engine

§Fuel injection pressure varies during the injection process

§Mechanical metering of fuel quantity to be injected in thecylinder

§Fuel injection timing mechanically controlled by Fuel

§Injection Pump & variable with engine speed

§High fuel consumption at low engine speed (due to imperfectair-fuel ratio)

§High emission at low engine speed (due to imperfect air-fuelratio)

§Mechanical control of exhaust gas recirculation into intakemanifold

§Poor air-fuel mixture causes particulate emissions

CRDi engine Pressures exceeding 1200 bar, uniformly maintainedDirect injection of high pressure fuelLess engine noise (Pilot injection prior to main injectionincreases compression pressure, thus reducing the noise)Injection pressure remains constant throughout the injectionprocessElectronically controlled metering of fuel quantityElectronically controlled injection timing & independent ofengine speedLow fuel consumption at all engine speeds (due to optimum airfuelratio)Low emission at all engine speeds (due to optimum air-fuelratio)Variable (electronic) control of exhaust gas recirculation intointake manifold - reduces NOx emission & delivers optimum performanceFinely atomized fuel results in efficient air-fuel mixing & reduced

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Different Names of CRDi technology

ØHonda's i-CTDi

ØHyundai-Kia's CRDi

ØMahindra's CRDe

ØNissan's NEO-Di

ØMitsubishi's DI-D

ØTata's DICOR

ØRenault's dCi

ØBMW's D-engines

ØFord Motor Company's TDCi Duratorq and Powerstroke

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Conclusion For environmentalists and those who are out to

make tighter emission rules, here is a brilliant

technology that promises to reduce and give

cleaner emissions to leave a healthier

environment behind for our next generation.

For engineers, it’s a milestone achieved in the

process of making way for the emission free

automobile.

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For engineers, it’s a milestone achieved in the

process of making way for the emission free

automobile.

This is what Engineering is all about, creating a

better tomorrow.

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The Common Rail Technology is an Engineering Marvel:

v Gives more POWER;

v Improved FUEL ECONOMY;

v Less POLLUTION; and last but not the least

v A DIESEL ENGINE whose noise levels match a

PETROL ENGINE

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