Thefrog ha scritto:
Egregio, vuoi dire che durante la fase di scoppio viene immesso 8 volte il gasolio a "piccole dosi" nella camera di scoppio mentre il pistone va giu'?
Se e' cosi' io ero rimasto a tre fasi. "ccidenti come vanno fortequesti della FIAT.
In pratica una iniezione pilota per ridurre il rumore, una pre iniezione per ridurre CO e HC, 2 iniezioni principali, una iniezione successiva per aiutare il catalizzatore più 3 eventuali iniezioni finali per il DPF e ridurre la diluizione dell'olio.
Praticamente ci sono due iniezioni principali invece che una sola del vecchio Multjet e 3 iniezioni finali per il DPF invece che una.
Guarda il simpatico schemino:
http://www.fptmultijet2.com/eng/up-to-8-injections/up-to-8-injections.php
Fiat poi dice questo:
The Multijet injector, capable of managing up to 5 consecutive injections in the same combustion cycle, was based on a hydraulic servovalve with an unbalanced shutter that required small sealing diameters and, consequently, longer strokes.
In the new Multijet II injector the shutter is hydraulically balanced, allowing larger sealing diameter with reduced shutter strokes. Thanks to this new servovalve, it is possible to control the fuel quantities injected into the combustion chamber with higher precision and speed. In such a way, it is possible to manage up to 8 consecutive injections with very accurate metering.
In particular the shutter stroke reduced to 20µm allows reducing dramatically the minimum time interval between two consecutives injection, until zero hydraulic dwell time. With these two consecutive injections it is possible to modulate the injection rate in order to achieve a better combustion process control. This new injection mode, called "Injection Rate Shaping", results in significant benefits in terms of noise, fuel consumption and emissions reduction.
The innovative MultiJet II servovalve allows a faster and more flexible injection events scheduling, like Injection Rate Shaping, which is the base for more and more advanced combustion control strategies.
With Injection Rate Shaping it is possible to reduce noise, fuel consumption and, in view of the Euro 6 limits, pollutant emissions.
Thanks to the Multijet II and IRS, the Diesel technology makes a big step towards the fulfilment of the future Euro 6 emissions standard, achieved with a combustion improvement while reducing the need of further aftertreatment devices.
