The engine has been outfitted with nozzles that spray water directly into the engine cylinders, cooling the intake charge. The effect enables a more aggressive engine tuning with higher compression ratios, reduced knock and earlier ignition timing.
BMW suggests power and torque output can be increased by up to 10 percent by combining the various benefits. As an added bonus, the approach is said to improve efficiency and reduce emissions.
Water injection was recently listed as a highlight innovation in ann M4 MotoGP safety car that previewed the M4 GTS package, however the company has not yet officially confirmed if the technology will carry over to the production model.
Most drivers might find it unusual to top off a water tank, as required in the M4 safety car. BMW suggests future production models would use a more convenient replenishing method, taking advantage of condensation produced by the air-conditioning system. Collected water is then drained into a frost-protected tank to avoid freezing in cold temperatures.
“Unless the vehicle is operated in exceptional climatic conditions, the system is fully self-replenishing, thanks to on-board water recovery,” the company notes.
The comments clearly point to production ambitions, but BMW has not yet detailed which models might be the first to arrive on the market with water injection.