Development of the High Power NADI™ Concept Using Dual Mode Diesel Combustion to Achieve Zero NOx and Particulate Emissions 2002-01-1744

Due to their high thermal efficiency coupled with low CO2 emissions, Diesel engines are promised to an increasing part of the transport market if their NOx and particulate emissions are reduced. Today, adequate after-treatments, NOx and PM traps are under industrialization with still concerns about fuel economy, robustness, sensitivity to fuel sulfur and cost because of their complex and sophisticated strategy.

New combustion process such as Homogeneous Charge Compression Ignition (HCCI) are investigated for their potential to achieve near zero particulate and NOx emissions. Their main drawbacks are too high hydrocarbons (HC) and carbon monoxide (CO) emissions, combustion control at high load and then limited operating range and power output.

As an answer for challenges the Diesel engine is facing, IFP has developed a combustion system able to reach near zero particulate and NOx emissions while maintaining performance standards of the D.I Diesel engines. This “dual mode” engine application called NADI™ (Narrow Angle Direct Injection) applies Homogeneous Charge Compression Ignition at part load and switches to conventional Diesel combustion to reach full load requirements.

At part load (including MVEG and FTP cycles), HCCI combustion mode allows near zero particulate and NOx emissions and maintains very good fuel efficiency close to an EURO III Diesel engine. At 1500 and 2500 rpm, NADI™ reaches 6 and 9 bar of IMEP with emissions of NOx and particulate under 0.05 g/kWh which means respectively 100 times and 10 times lower than a conventional Diesel engine.

At full load, NADI™ system is consistent with future Diesel engine power density standard. At 4000 rpm, 50/55 kW/l has been reached with conventional limiting factors and engine parameters settings.

Further development steps are also well identified, using advanced engine technology such as further generation of common rail fuel injection system, VVA or electric assisted turbocharger.