Just look at the BMW M4 GTS, which is the first production car to rubbish the idea. In the vehicle’s turbocharged six-cylinder engine, a water injection system offers improved performance and consumption even at full load.
And the punch line is that Bosch supplies water injection parts for the car that made it all possible.
The oddly named but relevant WaterBoost technology from Bosch is able to make engines more powerful and reduce fuel consumption by up to 13 percent by injecting water into the engine’s intake ducts that lead to the combustion chambers.
The fuel economy offered by the technology is more pronounced in three- and four-cylinder downsized engines, which are largely the cars of the masses.
Water injection can also deliver an extra kick in turbocharged engines. Earlier ignition angles mean that the engine is operated even more efficiently. Engineers were able to coax additional power out of the engine, even in powerful sports cars.
The basis of this innovative engine technology is a simple fact: an engine must not be allowed to overheat. To stop this happening, additional fuel is injected into nearly every petrol engine on today’s roads. This fuel evaporates, cooling parts of the engine block. With water injection, Bosch engineers have exploited this physical principle. Before the fuel ignites, a fine mist of water is injected into the intake duct. Water’s high heat of vaporisation means that it provides effective cooling.
Only a small volume of water is needed: for every one hundred kilometres driven, only a few hundred millilitre are necessary. As a result, the compact water tank that supplies the injection system with distilled water only has to be refilled every few thousand kilometres at the most.
And if the tank should run empty, the engine will still run smoothly – albeit without the higher torque and lower consumption provided by water injection.
Bosch said the use of water would not cause rusting. It said the water evaporates before combustion happens in the engine. All the water is expelled into the environment, together with the exhaust.
