H2O replaces CO2
Water injection for gasoline engines

Bosch's WaterBoost System is an innovative development for
powertrain systems that tap into as yet unimagined efficiency potential in
combustion engines. This not only makes mobility fuel-efficient and
lowers emissions, but it also enhances the fun to drive.

New engine performance due to hydropower
Bosch gives the combustion engine wings

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Additional information about Water injection of Bosch.

Information package for manufacturers

Summary Water injection

Information package for drivers

Summary Water injection

Good news: with Bosch WaterBoost, the combustion engine is once again ready to overtake and has its best days ahead. The secret of its success is a tuning formula with demineralized water, which boosts power generation, lowers fuel consumption, and minimizes concerns about CO2 emissions. So if you soon come across a turbocharged gasoline direct-injection engine, which despite concerted downsizing can keep the competition in its performance class on its toes even at high engine speeds, you'll know what's driving it: Bosch WaterBoost. From the world of motorsport. For more fun to drive.

up to

5% greater engine performance

without increasing engine displacement or boost pressure

up to

13% less fuel consumption

at higher accleration or long motorway journeys


up to

4% less CO2 emitted

in the WLTC*

*Worldwide harmonized Light-duty Test Cycle

With physics at its limits, now it's time to put chemistry into the mix
Innovative engine technology for more power and lower emissions

Due to Bosch's WaterBoost complete system – the only one of its kind in the world – the gasoline-driven powertrain is well on its way to redefining itself. When a direct-injection engine with little displacement but high levels of turbocharging is pushing its limits, bringing H2O into the mix of elements immediately pushes performance boundaries upward. The water actively cools the air-fuel mixture in the combustion chamber, thus reducing knocking that harms the engine, allowing earlier ignition, and ultimately resulting in increased engine performance. The higher compression ratio in the engine also leads to a CO2 reduction of up to 4% in WLTC. Overall, the combustion process takes place at a better temperature and therefore in a more controlled fashion. Ignition happens sooner and the earlier center of heat release leads to a better level of efficiency. Benefits that we make available for gasoline engines with water injection. More than anything else, we believe "Invented for life" means enriching everyday driving with genuinely tangible improvements.

Fundamental for improved fuel efficiency
The benefits of turbo air cooling

It's an exciting challenge: as soon as the really fun driving starts, even the strongest engine breaks into a figurative sweat and responds with an increasing thirst for fuel. In these high-load situations, a welcome dose of refreshment is just the thing: a microfine spray from Bosch WaterBoost. Sprayed directly into the intake port, the fine mist of water droplets cools the hot combustion air down to a tolerable level.

Successful WaterBoost effect: even at high engine speeds, the engine doesn't get "out of breath," since it receives the explosive air-fuel mixture sooner. And yet the result is not uncontrolled misfiring. That's because targeted use of water also protects the components in the powertrain interior. Incidentally, filling an additional tank with just 5 liters of the demineralized water lasts around 3,000 km. And even if the water runs dry from time to time, there's no effect on how the vehicle operates.

Water provides more oxygen
Advantages of improving engine performance

Horsepower is only truly powerful when it has enough room and air to give its driving force free rein. Whether or not turbocharging really gives direct-injection gasoline engines that extra kick forward is therefore decided in the highly compressed confines of the combustion chamber. Add in the fact that increasingly strict emissions guidelines of the past few years have not produced larger engine displacement; in fact, despite the rising overall demand for performance, it has actually gotten smaller.

If the horses under the hood are reined in more and more tightly, allowing them to "breathe" properly becomes even more important. That's why Bosch boosts oxygen saturation by cooling off the incoming charge air using water injection in the combustion chamber. The results are gratifying: driving is noticeably more dynamic and enjoyable and the engine freely shifts into gear for top performance. Up to 5% more horsepower with the same boost pressure and displacement? The proven technology makes this a thoroughly credible promise.

Engine to mechatronics: open the floodgates!
An overview of how WaterBoost works

Bosch wants to rationally revolutionize existing and proven direct-injection technology, now and tomorrow, without having to invest heavily in developing another part of the system. That's why Bosch deliberately designed WaterBoost as an auxiliary system that is easy to implement.

All that has to happen is to include the components needed for water injection in the structural plan and ensure that engine management incorporates them. Want a closer look at the technology? To the Bosch WaterBoost animation movie.