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The direct petrol injection is rather the thing of the past than the future of the automotive industry. The LPG sector must follow market trends, so that a modern car is very adaptable to gas fuelling.

For MPI engines (indirect injection into the intake manifold) such adaptation was simple - only one universal system was required (the system was calibrated after installing it in a specified car model). The installation of LPG systems in engines with direct petrol injection is more complicated, because they require an individual approach - for each engine code a dedicated controller software version is required. The autogas system manufacturers begin from the most common engines, but in many cases even the same engine type (theoretically identical) installed in a dozen of models of three or four related brands - typically has its specific features, that require a "customized" approach.

The Polish company AC S.A. uses the same approach to its STAG 400 DPI, i.e. a LPG vapour injection system that supplies the intake manifold, while using secondary injections of small amounts of petrol by  injectors factory mounted in the combustion chamber. The system is continuously updated to convert more and more DI engines that gradually replace older units with indirect injection. At present STAG 400 DPI supports dozens of engine codes belonging to different brands, obviously many of them are installed  in VW Group cars (Volkswagen, Audi, Skoda and Seat), where DI engines have been installed for quite a long time (already Golf V was powered by FSI engines) and MPI drive units practically are not being offered now.

In 2015 alone the company AC S.A. introduced three upgrades to the STAG 400 DPI controller to expand available range of applications. In February the Toyota engines of 1AZ-FSE code and VW BDX (2.8 FSI in Audi A6 and A8) were added, in May the list of supported units was extended by  the Opel A20NHT engine and all 1.6-2.0 l four-cylinder engines  manufactured by VW before 2012.

However, this does not close the list of modifications - at the same time the functionality of the controller was expanded by supporting AC W02 and W02 BFC injectors, operating stability when idling was improved (even then the engine is working partially on LPG), selection of reducer temperature sensor type is allowed and new gas level sensor types were added, and the share of petrol in combustion was reduced. On the other hand, (in firmware v. 2.0.2 introduced in July 2015) an option to increase petrol dosage within the selected load and RPM ranges for engines that require it.

Will the list of modifications be closed and completed? Surely not yet, as the functionality of the controller follows the evolution of petrol engines. Until the STAG 400 DPI is replaced by a next entirely new model (although this is a question of the future), the present model will be continuously developed to keep pace with market changes. It is important to shorten the time between a new solution is introduced by a car manufacturer, and the adaptation of the controller to such modification. Although, only a few cars drive directly from the showroom to the autogas installation service centres, but modifications need some time, and  the competition does not miss any opportunity, so keeping abreast is well doing. This is no problem for AC S.A.