ByKEDAR D. GOKHALEME 02 M 094(Tata Technologies Ltd)

Exhaust Emissionsreduction (Air Pollution)Better NVH & DriveabilityFuel Economy improvement(CO2 - Global warming)Safety aspectsCompetitive Costs

I.C. Engines; Still adominant prime moverfor automobiles !However

Challenges exist !

(..Contd)

Direct Injection DieselEngine

with Flexible FIE viz.Common Rail System

can offer:ü Reduced Combustion Noiseü Diffused NOx – PM Trade-offü High specific power output

Hence“Common Rail”

has become a buzzword inAutomotive Industry.

1) Start Diesel Injection...- at the right Moment (Injection Timing)- in the right Quantity (and Rate !)- in the right Form (Atomization & Penetration)- Consistently

- Cycle by Cycle- Cylinder to Cylinder- Over a Period of Time

2) End the Injection sharply.

n Mechanical Systemsn - Pump – Line – Injector

n In line Typen Rotary Distributor Typen Unit Pump Type

n Unit Injectors

n Electronic Systemsn - Pump – Line - Injector

n Electronic Inline Typen Electronic Rotary Typen Electronic Unit Pump

n Electronic Unit Injector

n Common Rail Systemn Solenoid Operated

n Unbalanced Servo Valven Balanced Servo valve

n Piezo Operatedn Servo valve typen Direct acting type

Common Rail System is a modular, e’controlled diesel injection system offeringclosed loop flexible control of Injection

A “Rail” which is commonfor all cylinders, stores thefuel at high pressure anddelivers it to each cylinderat almost constant pressure.

Hence the name“Common Rail”

01 = H.P.Pump02 = Element Shutoff valve03 = Rail Pressure Sensor04 = Pressure-limiter Valve05 = H.P. Accumulator (Rail)06 = Injector07 = Phase sensor08 = HFAMS09 = Fuel Filter10 = Boost Pressure Sensor11 = Feed Pump12 = Bi-Metal valve13 = Coolant temperature Sensor14 = Turbocharger15 = Return line valve16 = Speed Sensor17 = Vacuum Valve18 = EGR Pressure Transducer19 = Vacuum Reservoir20 = Fuel Tank21 = In Tank Fuel Pump22 = Battery23 = Accelerator Pedal Position

Sensor

High Pressure Pump (Bosch)

High Pressure Rail C.R. Injector

01: Fuel Return02: Solenoid Connector03: Solenoid Assembly04: H.P. Fuel Inlet05: low pressure zone06: Ball Valve07: Fuel Path to Nozzle08: Fuel Path to Ball Valve09: Needle Stem10: Nozzle11: Needle

v Heterogeneous Combustionv Smoke limited Power Outputv Always Lean (Overall AFR 20 ~ 80)v Criticality of In Cylinder Flowsv Quality Governed

Fuel Injection Parameters are Critical...

Common Rail advantages:n Injection Pressure fairly independent of Engine Speed & Load.n Multiple Injections (Pilot, Main, Post) for better emissions & NVH.n Commonization of parts across Variants (Diesel & Gasoline)n Flexible and accurate Timing Controln Flexible Injection Rate Controln Flexible Torque Curve Shape Controln Additional control on

n EGRn Turbochargern Particulate Trap

n Improved Cycle to Cycle Controln Improved Cylinder to Cylinder controln Additional Parameters Processing capabillity

Evolution of DI Diesel Engine forPassenger Cars

Max. Injection Pressure: 1350 barNo Injection Rate ShapingPilot Injn 1.5 mm3/St @ 500 barSwirl Ratio : 2.5C.R. : 18.5BHP / Litre : 57.1Torque Nm / Litre : 130

Max. Injection Pressure: 900 barTwo Spring Injector(Rate Shaping)No Pilot InjectionSwirl Ratio : 3.0C.R. : 20BHP / Litre : 51.7Torque Nm / Litre : 100

Max. Injection Pressure: 700 barNo Injection Rate ShapingNo Pilot InjectionSwirl Ratio : 3.5C.R. : 18BHP / Litre : 47.6Torque Nm / Litre : 95

Example: Fiat 1.9 L TCIC Engine (Bosch)

MechanicalDistributor Pump

ElectronicDistributor Pump

Common RailInjection

Sr Engine Description ApplicationBore xStroke

Enginecc

C.R.Max Power kW

(hp) @ RPMMax TorqueNm @ RPM

BHP per Litre

1DuraTorq, 4 cyl CR DI,16V DOHC, VGTCIC

Ford Mondeo 86 x 86 1998 19 83 (113) @ 4000 280 @ 1900 57

2Merc, 4 cyl CRDI, 16VDOHC, TCIC

MercedesC 200 CDI

88 x 88.3 2148 18 84 (114) @ 4200 250 @ 2300 53

3Hyundai, 3 cyl, CRDI,12V DOHC

HyundaiAccent

83 x 92 1493 18 60 (82) @ 4000187 @ 2000 ~

2700 55

4Toyota, 1.4D-4D, 4 cylCRDI, 8V SOHC

Toyota YarisVerso D-4D

73 x 81.5 1364 19 55 (75) @ 4000170 @ 2000 ~

2800 55

5 Hyundai 4 Cyl CRDI Terracan 97.1 x 98 2902 19 110 (150) @ 3800 333 @ 2000 51.7

6Fiat, 4 cyl, CRDI, 16VDOHC, Multijet

Fiat Punto 69.6 x 82 1251 N.A. 51 (70) @ 4000 180 @ 1750 56

7Fiat, 4 cyl, CRDI, 8VSOHC, Multijet

Fiat Punto 82 x 90.4 1910 18 74 (100) @ 4000 259 @ 1750 52.3

BHP / litre for Typical DI Diesel Engine with Mechanical FIE = 45~48

Nox P.M. NVHPowerDensity

Fueleconomy

CombustionSystem

2 Valves percylinder

4 Valves percylinder a a a a

Fuel InjectionSystem

Mechanical(Rotary) Pump

Common Rail a a a a aAftertreatment

Oxidationcatalyst

Lean NoxCatalyst a

BoostingSystem

Fixed geometryTurbo

VariableGeometry turbo a a a a

Actuator Pneumatic Electric a aBase Structure

C.I. &Aluminium

Aluminium a

Advantage over PresentEngineFeature

Present DIDiesel

Emerging DIDiesel