Audi is introducing a mechanism to prevent misfueling of diesel vehicles with gasoline. It's generally not possible to put diesel into a gasoline-powered vehicle as the larger diesel nozzles won't fit in the filler neck. However, the smaller gas nozzles will fit in the diesel neck. Audi's system adds a flap in the neck to prevent fuel flow. The flap only opens if the nozzle presses on contact points just below the cap. The smaller gasoline nozzle won't be be able to hit all of the contacts at once and the flap will prevent fuel from getting into the tank. Apparently, the improved refinement of modern diesel engines has led to an increase in misfueling in recent years, prompting Audi to add the new feature. Audi's system is set to appear next year.

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