injection systems requirements

INJECTION SYSTEMS INJECTION SYSTEMS REQUIREMENTSREQUIREMENTS

Outlook for electrostatic Outlook for electrostatic atomization in automotive atomization in automotive

applicationsapplications

Rodica A. BaranescuRodica A. Baranescu

Workshop on Electrostatic Workshop on Electrostatic Atomization, March 2-4, 2009Atomization, March 2-4, 2009

Traditional requirementsTraditional requirements

• Accurate fuel metering per cycle for load controlAccurate fuel metering per cycle for load control

• Provide vaporization and distribution in combustion spaceProvide vaporization and distribution in combustion space

• Provide the mixture in correct proportion under all Provide the mixture in correct proportion under all conditions (start/acceleration/full power)conditions (start/acceleration/full power)

• Protect sensible components in the injector from damage Protect sensible components in the injector from damage by deposits in the fuel or by debrisby deposits in the fuel or by debris

Drivers for Fuel Injection Drivers for Fuel Injection RevolutionRevolution• Stringent emission standards for NOx and Stringent emission standards for NOx and

particulates, requiring combustion controlparticulates, requiring combustion control– Euro V; US 2007; US 2010Euro V; US 2007; US 2010

• Fuel consumption and GHG reduction pressureFuel consumption and GHG reduction pressure• More stringent “sociability” requirements for CI More stringent “sociability” requirements for CI

engines engines – driving fun: acceleration, low end torquedriving fun: acceleration, low end torque– improved comfort: low noise, easy startimproved comfort: low noise, easy start

• Competition with SI and hybrids (for CI engines)Competition with SI and hybrids (for CI engines)• Fuel injection progress seen in both SI and CI enginesFuel injection progress seen in both SI and CI engines

Advanced Requirements for Advanced Requirements for InjectionInjection

• Increase of operating pressureIncrease of operating pressure• Injection rate control and flexibilityInjection rate control and flexibility• Multiple injections per cycle (of Multiple injections per cycle (of

determined duration and quantity)determined duration and quantity)• Electronic control and management of Electronic control and management of

injection process injection process

Dimensions of Modern Injection Dimensions of Modern Injection TechnologyTechnology

Challenges for injection Challenges for injection systemssystems

• Reduce injector depositsReduce injector deposits– High temperature 120High temperature 12000C; 2000 bars; small clearancesC; 2000 bars; small clearances

• Reduce oxidation due to heat entrainment in fuel systemReduce oxidation due to heat entrainment in fuel system• Improve fuel quality worldwide to provide robustness to Improve fuel quality worldwide to provide robustness to

modern fuel systemsmodern fuel systems• Develop new additive technology for increased detergencyDevelop new additive technology for increased detergency• Deal with new fuels (biodiesel) and its poor oxidation Deal with new fuels (biodiesel) and its poor oxidation

stabilitystability• Develop new materials and technology for injectorsDevelop new materials and technology for injectors• Develop new software for injection managementDevelop new software for injection management• Strive for global fuel specifications matched to Strive for global fuel specifications matched to

requirementsrequirements

Injection Rate FlexibilityInjection Rate Flexibility

Provides:Provides:• combustion controlcombustion control• Rate of pressure riseRate of pressure rise• NoiseNoise• NOx formationNOx formation

Development Targets for Injection Development Targets for Injection SystemsSystems

• Improved nozzle design (including orifices)Improved nozzle design (including orifices)• Enhanced metering accuracyEnhanced metering accuracy• Increased injection pressure Increased injection pressure • Multi injection capability (for combustion Multi injection capability (for combustion

control in CI engines)control in CI engines)

Gasoline Manifold Injection Gasoline Manifold Injection (external)(external)

Gasoline Direct Injection Gasoline Direct Injection (internal)(internal)

Gasoline InjectionGasoline Injection

Common Rail Fuel Injection Common Rail Fuel Injection SystemSystem from Delphi Common Rail System with Direct Acting Injector, MTZ 10/2008, Volume 69from Delphi Common Rail System with Direct Acting Injector, MTZ 10/2008, Volume 69

Common Rail Fuel Injection Common Rail Fuel Injection SystemSystemfrom “2000 bar Diesel Common Rail by Bosch for Passenger Cars” , MTZ 10/2008, from “2000 bar Diesel Common Rail by Bosch for Passenger Cars” , MTZ 10/2008, Volume 69Volume 69

Common Rail System FeaturesCommon Rail System Features

• High pressure - independent of injection cycle and engine speedHigh pressure - independent of injection cycle and engine speed• Constant high pressure during injectionConstant high pressure during injection• Allows more than one injection per cycleAllows more than one injection per cycle• Square rate of discharge at full and low loadSquare rate of discharge at full and low load• Penalty in noise and high pressure rise in combustion chamberPenalty in noise and high pressure rise in combustion chamber

Multiple injections patternsMultiple injections patterns

1 pre-injection; 2 main injection; 3 steep rise; 4 boot shape; 5 gradual rise; 1 pre-injection; 2 main injection; 3 steep rise; 4 boot shape; 5 gradual rise; 6 gradual drop; 7 steep drop; 8 close secondary; 9 late post-injection6 gradual drop; 7 steep drop; 8 close secondary; 9 late post-injection

Common Rail Fuel Injection Common Rail Fuel Injection SystemSystem from “Delphi Common Rail System with Direct Acting Injector”, MTZ 10/2008, from “Delphi Common Rail System with Direct Acting Injector”, MTZ 10/2008,

Volume 69Volume 69

Piezo Electric InjectorPiezo Electric Injector

• Needle hydraulically actuated by piezo stackNeedle hydraulically actuated by piezo stack• Weight reduced (two fold)Weight reduced (two fold)• Up to 5 injections (closed coupled) per cycle Up to 5 injections (closed coupled) per cycle • Allows precise injections of small quantities (1mmAllows precise injections of small quantities (1mm33) ) • Lower fuel leakage rates ( requires smaller pump)Lower fuel leakage rates ( requires smaller pump)

ConclusionsConclusions

• Fuel injection system complexity has increased substantiallyFuel injection system complexity has increased substantially• Design and packaging is additionally challenging Design and packaging is additionally challenging • Lower pressure injection systems seem more suitable to Lower pressure injection systems seem more suitable to

electrostatic atomizationelectrostatic atomization• Viscous fuels and liquids and large injection systems seem Viscous fuels and liquids and large injection systems seem

also suitable to electrostatic chargealso suitable to electrostatic charge• Approach is interesting and improved atomization is Approach is interesting and improved atomization is

worthwhile; potential for new hardware designs is significantworthwhile; potential for new hardware designs is significant