MAHLE is developing a combination of activated carbon filter and ion exchanger. This treatment module allows the dedicated tank in the vehicle to be filled with tap water, which is then treated on board for injection in the engine.

Water injection in a gasoline engine protects components at high engine speeds and loads by preventing mixture enrichment and reduces pollutant emissions in partial-load operation. Existing systems use a water tank that must be regularly refilled with de-ionized water.

The compact design of the MAHLE treatment module means it can be installed at various locations in the vehicle. It also can be integrated in the infeed to the tank, but this has disadvantages in terms of the contact time between the tap water and the filter and ion exchange medium during the filling process, according to the company. Inline installation as a bypass of the water pump or in the tank, or as an inline element upstream of the injectors, has proven to be promising. The latter variant, in particular, has palpable benefits in terms of costs and serviceability.

The concept of filling the tank with tap water presents tough requirements, especially considering local markets, as water quality and composition vary greatly around the world. MAHLE benefits from its global expertise in the areas of filtration and engine technology and incorporates the results of regional tests in the development, according to the company. As part of the ongoing tests, MAHLE is investigating the treatment of water that is obtained on board during vehicle operation. Water sources include the air conditioning system and the exhaust gas flow, which has a water content of about 13 percent for stoichiometric combustion.