common rail diesel injection _read-only_
Post on 26-Dec-2014
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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
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