BMW revealed a prototype of its 1-series that is powered by a water-injected turbo petrol unit, at the BMW Group Innovation Days 2015.

The prototype gets a 1.5-litre three-cylinder turbo petrol engine that makes 215bhp. BMW has explained the working of the engine saying that water is injected as a fine spray, it evaporates and extracts energy from its surroundings, thereby reducing combustion temperatures in the engine by
25° C.

The reduced temperatures create a cooling effect, avoiding the need to inject additional fuel when operating at or near full throttle. A point to be noted is that, even the BMW M4 MotoGP safety car draws water from a five-litre tank in the boot. The direct water-injection system in this 1-series prototype doesn’t need topping up during  everyday use, as the water supply is continuously replenished by the recovery of condensed water from the air conditioning system.