Development of a Fuel System Cleanliness Test Method in a Euro 4 Direct-Injection Gasoline Engine (VW 1.4 L TSI 90 kW) 2017-01-2296

Driven by increasingly stringent tailpipe CO₂ and fuel economy regulations, gasoline direct injection (GDI) engines are enjoying rapidly increasing market penetration. Already more than 50% of newly produced vehicles in the US and western Europe employ direct-injection technology and many markets in Asia are also seeing an increasingly rapid uptake.

However, with the adoption of GDI engine technology, which is able to push the boundaries of engine efficiency, new challenges are starting to arise such as injector nozzle deposits, which can adversely affect performance. Multi-hole solenoid actuated fuel injectors are particularly vulnerable to deposits formed when operated on some market fuels. In order to address this challenge, the development of a reliable industry test platform for injector cleanliness in GDI engines is currently underway in both the US and Europe.

This study shows the successful application of a mass produced GDI bench engine test platform (VW 1.4 L TSI 90 kW; engine code CAXA; engine family EA111) to differentiate different fuel formulations, at a 99% statistical confidence level, based on an engine metric correlated to injector cleanliness. In this study, a European (EN228 compliant) market representative test fuel was used throughout the entire investigation -i.e. no pro-fouling dirty-up fuel components were required to accelerated deposit formation within a reasonable test duration. The study makes two cross-comparisons between three different fuel formulations and the bench engine deployed is shown to be a highly sensitive test platform to differentiate fuels with different levels of deposit control additive (DCA). Fuels formulated with appropriate DCAs help restore fouled injectors to their original performance level.