When Lexus unveiled its first GS450h in 2005, it had something unique, never seen before on a gas engine: a dual fuel injection system. Motorists have the choice of an indirect (in the intake port) or a direct fuel injection, but the Japanese engineers chose to use both systems. Each cylinder has 2 injectors, as the Lexus illustration on the left proves, and it’s a computer that commands which injector to use at any given moment. It’s the best of both worlds, with the excellent fuel economy and top end power of direct fuel injection, with the clean burning of an indirect set-up where gas and air have more time to mix. There’s only one flaw, in the cost of such a system. 2 injectors cost more than a single one, but that’s the tip of the iceberg. A dual fuel injection system is a nightmare to fine-tune. Engineers will have to work long hours, and that may be acceptable on a Lexus, but few people thought this technology could sometimes be available on cheaper models. Well, this may change with Volkswagen.
The German company should bring to market a 4 cylinder with a direct and indirect fuel injection within 12/18 months. It would launch first on an Audi, but as always with Volkswagen, the technology shall progressively be available on lesser models within the group.