Water instead of gasoline: Bosch innovation reduces fuel consumption by up to 13%

Did you know that even advanced gasoline engines waste roughly a fifth of their fuel? Especially at high engine speeds, some of the gasoline is used for cooling instead of for propulsion. With its new water injection, Bosch shows that it does not have to be that way. Particularly when accelerating quickly or driving on the freeway, the injection of additional water makes it possible to reduce fuel consumption by up to 13%.

“With our water injection, we show that the combustion engine still has some tricks up its sleeve,” says Rolf Bulander, chairman of the Bosch Mobility Solutions business sector and member of the board of management of Robert Bosch GmbH.

The fuel economy offered by this Bosch technology comes especially to the fore in three- and four-cylinder downsized engines. But it is not only in the area of fuel economy that the Bosch innovation comes into play. It can make cars more powerful as well.

“Water injection can deliver an extra kick in any turbocharged engine,” says Stefan Seiberth, president of the Gasoline Systems division at Bosch. Earlier ignition angles mean that the engine is operated even more efficiently. On this basis, engineers can 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 from happening, additional fuel is injected into nearly every gasoline 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.

This is also the reason why only a small additional volume of water is needed: for every one hundred kilometers driven, only a few hundred milliliters 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 kilometers at the most.

And if the tank should run empty, there is nothing to worry about: the engine will still run smoothly – albeit without the higher torque and lower consumption provided by water injection.