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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. Intensified EGR cooling. CICERO EGR project. NOx fuel consumption trade-offs. US 07 NOx-Scenarios. Injection (pressure, Multi-hole nozzle, strategy …).
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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
Intensified EGR cooling CICERO EGR project NOx fuel consumption trade-offs US 07 NOx-Scenarios Injection (pressure, Multi-hole nozzle, strategy …) Intensified EGR cooling Correlation between emissions reduction and fuel consumption in passenger car DI diesel engines (study supported by FFV workgroup) [Lamping et al., MTZ, 07/01 ].
Required increase of boost pressure to implement 10% EGR at a constant speed [Arnold, 2004].
The Low Pressure EGR circuit : • 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 High Pressure EGR circuit : • Negative pressure differential between turbine outlet and compressor outlet • Fouling of the EGR cooler • Coordination of EGR valve/VGT vanes
Thermodynamic comparison of the LP and HP EGR loops : Passenger car, specific output power of 50kwk/l 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]
Commercial Vehicle engine, 400kW @ 1900 rpm Operating points on the compressor map for 100% load and 1.7λfor HPL and LPL of a Euro III – Euro IVengine (Langridge and Flesser, 2002)
HPL EGR LPL EGR 100% load, 1.7 Air Excess, 80% rated speed Commercial Vehicle engine, 400kW @ 1900 rpm 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 Required amount of EGR : 20% Compressor Efficiency : 77% Turbine Efficiency: 75% Virtual turbocharging system enabling to reach sufficient amount of EGR to fulfill Euro 5 (Langridge and Flesser, 2002)
Regulated Two-stage Turbocharging System, R2S (on 4 cyl. 4,6L engines, other?) High pressure stage turbocharger bypass Air charge cooler Low pressure stage turbocharger bypass (VGT as an alternative to the wastegate) Alternative, promising , future turbocharging systems to implement high amount of EGR: Two stage turbocharging systems (Buchwald et al., 2006)
Commercial Vehicle engine, 400kW @ 1900 rpm Two stage turbocharging compressor map enabling to reach sufficient amount of EGR to fulfill Euro 5 (Langridge and Flesser, 2002)
Two stage turbocharging systems (Buchwald et al., 2006) Aim : combustion lambda λc= 2 Inlet charge temperature = 40ºC EGR-rate = 60% Full load characteristics of the engine
2 radial compressor wheels in series The Low speed turbo by Garett Engine boosting System (S. Arnold, 2004)
Performance of the LST compressor stage against the state of the art single stage compressor (Arnold, 2004)
Numerical Calculations 1 D Simulation for new EGR circuit configurations Experience, know how Testing & calculation database Bibliographic Research Simulations For refining? Test bench? Ideas Think-Tank N Configurations …. Selection of the more promising configurations
Two stage turbocharging systems (Buchwald et al., 2006) Aim : combustion lambda λc= 2 Inlet charge temperature = 40ºC EGR-rate = 60% Full load compressor map