Downsizing and the introduction of direct injection have generated a lot of progress of the Gasoline engine towards Diesel engine CO2 emissions. Besides the advantages of Gasoline engines in terms of tail pipe emissions and its well-known cost advantages, the use of a turbo charger is also generating the fun to drive due to the high low end torque known from turbo charged Diesel engines.
The future demanding targets for fuel economy up to 2020 will create additional challenges for Gasoline engines, and in particular for GDi engines, due to the currently proposed particulate numbers (PN) targets. The new European legislation Euro 6 proposes a target for Gasoline engines similar to the current PN regulation for Diesel engines. In order to preserve the cost advantage of the Gasoline over the Diesel engines it is necessary to find cost effective solutions without additional after-treatment systems.
To this end Delphi has developed the Multec 20HI outwardly opening injector based upon the Multec 20 injector for lean stratified applications [1]. The Multec 20HI uses a solenoid driven actuator concept in combination to a reduced valve diameter in order to maintain the advantages in spray atomization and mixture preparation of the outwardly opening nozzle while allowing substantial simplifications in the injector design. This paper discusses control strategies and fuel system component requirements particularly in support of reducing particulate emissions. On the control side, injection timing and injection splitting are important parameters, especially under catalyst heating, engine warm-up and high-load conditions. On the component side, mixture formation in regard to evaporation rate and penetration is a key factor.