Martin Hardy

The Impact of Injection Strategies on Emissions Reduction and Power Output of Future Diesel Engines

ABSTRACT Future light, medium and heavy duty diesel engines will need to satisfy the more stringent emission levels (US 2014, Euro 6, etc.) without compromising their current performance and fuel economy, while still maintaining a competitive cost. In order to achieve this, the Fuel Injection Equipment (FIE) together with the pressure charging, cooling system, exhaust after treatment and other engine sub-systems will each play a key role. The FIE has to offer a range of flexible injection characteristics, e.g. a multiple injection train with or without separation, modulated injection pressures and rates for every injection, higher specific power output from the same injector envelope, and close control of very small fuel injection quantities. The aim of this paper is to present Delphi’s developments in fuel injection strategies for light and medium duty diesel engines that will comply with future emission legislation, whilst providing higher power density and uncompromised fuel economy.

Delphi Common Rail system with direct acting injector

In 2008 Delphi will bring into production a ground-breaking concept in diesel fuel injection technology years ahead of the competition: the Direct Acting piezo technology for diesel engines. In the 2000 bar Delphi Direct Acting Common Rail system, the injector needle is set in motion directly by a piezo-ceramic actuator, rather than being moved via an electro-hydraulic circuit. Ultra-fast needle opening and closing independent of the injection pressure leads to improved emissions and fuel consumption whilst breaking new levels in power density and engine torque. Maximum controllability of small pilot injections with exceptional multiple injection stability over lifetime guarantee a premium injection performance.

Common-Rail-Einspritzung mit Direct-Acting-Injektor von Delphi

2008 bringt Delphi ein innovatives Diesel-Einspritzsystem zur Serienreife: die Direct-Acting-Piezo-Technik. In diesem 2000-bar-Common-Rail-System wird die Dusennadel direkt von einem piezokeramischen Aktuator angetrieben und nicht uber eine servohydraulische Schaltung. Sehr schnelles, vom Einspritzdruck unabhangiges Offnen und Schliesen der Nadel ermoglicht niedrigste Emissionen bei gleich zeitig geringem Kraftstoffverbrauch, wahrend neue Dimensionen bei Leistungsdichte und Motordrehmoment erreicht werden. Die optimale Kontrolle uber kleinste Piloteinspritzmengen, verbunden mit herausragender Mengenstabilitat uber die gesamte Lebensdauer, garantieren erstklassige Kraftstoff einspritzung.