eric ollivier 07/06/05
DESCRIPTION
New gas exchange system to provide high amount of EGR in DI diesel engines – A preliminary literature survey. Eric Ollivier 07/06/05. Intensified EGR cooling. CICERO EGR project. NOx fuel consumption trade-offs. US 07 NOx-Scenarios. Injection (pressure, Multi-hole nozzle, strategy …). - PowerPoint PPT PresentationTRANSCRIPT
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New gas exchange system to provide high amount of EGR in DI diesel engines – A preliminary literature
survey.
Eric Ollivier
07/06/05
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NOx fuel consumption trade-offs
Injection (pressure,Multi-hole nozzle, strategy …)
Intensified EGR cooling
US 07 NOx-Scenarios
CICERO EGR project
Correlation between emissions reduction and fuel consumption in passenger car DI diesel engines (study supported by FFV workgroup) [Lamping et al., MTZ, 07/01 ].
Intensified EGR cooling
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Required increase of boost pressure to implement 10% EGR at a constant speed [Arnold, 2004].
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• Positive pressure differential between turbine outlet and compressor inlet
• DPF
•Two stages of cooling : less EGR needed
• Condensation : liquid water and lubricating oil, and acid solution in the intake area
• Big intake volume : homogeneous mixture but high response time
The Low Pressure EGR circuit :
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• Negative pressure differential between turbine outlet and compressor outlet • Fouling of the EGR cooler • Coordination of EGR valve/VGT vanes
The High Pressure EGR circuit :
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Thermodynamic comparison of the LP and HP EGR loops :
Reduced Mass Flow as a function of the compressor pressure ratio, in HP and LP EGR loop to provide 30% EGR at 2500 rpm and
12 bar BMEP [Weber et al., 2005]
Passenger car, specific output power of 50kwk/l
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Lambda maps :
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PMEP maps :
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BSFC maps :
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Operating points on the compressor map for 100% load and 1.7λ for HPL and LPL of a Euro III – Euro IV engine (Langridge and Flesser, 2002)
Commercial Vehicle engine, 400kW @ 1900 rpm
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HPL EGR LPL EGR
100% load, 1.7 Air Excess, 80% rated speed 100% load, 1.7 Air Excess, 80% rated speed
BSFC/NOx trade-off for 100% load, 80% rated speed and 1.7 air excess ratio for HPL and LPL (Langridge and Flesser, 2002)
Commercial Vehicle engine, 400kW @ 1900 rpm
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Virtual turbocharging system enabling to reach sufficient amount of EGR to fulfill Euro 5 (Langridge and Flesser, 2002)
Compressor Efficiency : 77% Turbine Efficiency : 75%
Required amount of EGR : 20%
Commercial Vehicle engine, 400kW @ 1900 rpm
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(VGT as an alternative to the wastegate)
bypass
Low pressure stage turbocharger
Regulated Two-stage Turbocharging System, R2S (on 4 cyl. 4,6L engines, other?)
Air charge cooler
bypass
High pressure stage turbocharger
Two stage turbocharging systems (Buchwald et al., 2006)
Alternative, promising , future turbocharging systems to implement high amount of EGR:
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Two stage turbocharging compressor map enabling to reach sufficient amount of EGR to fulfill Euro 5 (Langridge and
Flesser, 2002)
Commercial Vehicle engine, 400kW @ 1900 rpm
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Full load characteristics of the engine
Aim : combustion lambda λc= 2Inlet charge temperature = 40ºCEGR-rate = 60%
Two stage turbocharging systems (Buchwald et al., 2006)
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2 radial compressor wheels in series
The Low speed turbo by Garett Engine boosting System (S. Arnold, 2004)
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Performance of the LST compressor stage against the state of the art single stage compressor
(Arnold, 2004)
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Intermediate EGR route, (Arnold 2004)
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Testing & calculation database
Experience,know how Bibliographic
Research
Ideas
Think-Tank
N Configurations
Numerical Calculations
Selection of the more promising configurations
SimulationsFor refining?
1 D Simulation for new EGR circuit configurations
Test bench?
….
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Full load compressor map
Aim : combustion lambda λc= 2Inlet charge temperature = 40ºCEGR-rate = 60%
Two stage turbocharging systems (Buchwald et al., 2006)