Mahle's Water Injection System Uses Tap Water
Mahle has come up with a water injection solution for engines that can use tap water. To make this possible, the manufacturer has developed a treatment module which combines a carbon filter and an ion exchanger.
Water injection in a petrol engine prevents mixture enrichment for component protection at high engine speeds and loads and reduces pollutant emissions in partial-load operation. Existing systems use a water tank that must be regularly refilled with de-ionised water. To facilitate this refilling process for the driver, Mahle has developed 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 into the engine.
According to Mahle, the compact design means the treatment module can be installed at various locations in the vehicle. It can also be integrated into 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. However, 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.
Tests using on-board water sources
As part of the ongoing tests, Mahle is also 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.