HYDROPOWER : Water Injection for gasoline passenger cars fit for all driving conditions

Recently CO₂ emission limits in Europe have been tightened. In 2021, passenger car CO₂ emissions should not exceed 95 g CO₂/km. In 2025, 81 g CO₂/km becomes the next standard.

Thanks to the constant optimisation of internal combustion engines, average CO₂ emissions over the European passenger car fleet has been constantly reduced from almost 180 g CO₂/km in 2000 to less than 120 g CO₂/km in 2015. However in the last 2 years, we observe again an increase in the average CO₂ emission of the European passenger car fleet.

The cause of this increase is amongst others a switch from diesel to gasoline vehicles, which have a lower engine efficiency compared to diesel vehicles.

A significant improvement of gasoline internal combustion engines is mandatory. Water injection efficiently reduces combustion chamber temperatures, which opens a full panel of engine improvements, such as compression ratio increase, specific power output increase, engine and exhaust system protection.

Additionally the emissions at engine start can be more easily managed.

This paper describes the progress made in the last few years and highlights the key enablers for the implementation of this technology in our passenger cars. A particular focus is put on making the system fit for all driving conditions.