Click the 335d for a high res gallery

One of the risks of owning and operating a diesel vehicle is mis-fueling. Just as putting diesel fuel in the tank of a gas-powered vehicle will cause some very expensive damage, so to will gas in a diesel tank. The former is largely prevented by the use of two different sized nozzles. Diesel nozzles on pumps are larger in diameter than gas nozzles so they don't physically fit. However, it's not uncommon for drivers to mistakenly insert a smaller gas nozzle into the diesel fill neck on the vehicle.

BMW has devised a mechanism that locks the flap in the filler neck to prevent fuel flow if the smaller nozzle is inserted. Only the larger diesel nozzle will unlock the flap allowing fuel to flow. The new system is now standard on all diesel-equipped BMWs, both in Europe and North America, including the new 335d and X5 xDrive35d. Hopefully, BMW will share this technology with other automakers.

Photos Copyright ©2008 Sam Abuelsamid / Weblogs, Inc.


Munich. BMW is the first car manufacturer to equip all new diesel-powered models with an Incorrect Fuelling Protection System as standard equipment. The innovative system helps prevent cases of misfuelling at the pump and its far-reaching consequences. A special mechanism fitted to the filler neck prevents drivers from accidentally inserting the fuel filler nozzle of a standard unleaded gasoline pump into the filler neck of a diesel-powered car. This technology has been tried-and-tested in a variety of BMW models with diesel engines and will now be fitted to all diesel-powered BMW models, including the 335d Sedan and X5 xDrive35d now on sale in the US, right from the factory.
Every year, the German AA has to provide technical support in more than 5,000 cases of diesel misfuelling. Rectifying the consequences of incorrect fuelling is not just time consuming, it may also involve major costs. Even if the driver realizes their mistake before starting the engine, emptying and cleaning the fuel tank, pipes and the pump as well as changing the filter will be unavoidable.

The high number of cases of misfuelling shows that just a short moment of inattention suffices to select the wrong fuel filler nozzle at the gas station. Particularly drivers who frequently use different cars from rental companies or company fleets often have to pay extra attention – more so, since the performance profile and acoustic insulation measures of modern diesel engines reduce the differences between diesel and gasoline-powered engines to a minimum. The difference in fuel filler nozzle diameter often prevents accidentally filling petrol engines with their narrower filler neck with diesel fuel, but during hasty filling manoeuvres, the filler nozzle for unleaded gasoline can easily and mistakenly be inserted into the filler neck of standard diesel models.

However BMW will help drivers to avoid making this mistake. The Incorrect Fuelling Protection System fitted to all BMW diesel-powered models is designed to allow only filler nozzles for diesel fuel to enter the filler neck. The filler neck of these models is fitted with a locking system that can only be released by a standardized diesel filler nozzle. An unleaded gasoline nozzle with its smaller diameter cannot make the same connection and its access is blocked.

The Incorrect Fuelling Protection System is also designed for fuelling under exceptional circumstances, when the diesel-powered model may have to be fuelled from a spare can. Narrow recesses on the outer walls of the filler neck allow the introduction of smaller amounts of fuel. Using a container for re-fuelling requires extra care, which serves to remind the driver of ensuring that they use the right type of fuel.

Share This Photo X