Internal combustion engines waste an estimated 20 % of the total fuel which they consume, by using it for cooling down the engine instead of propulsion. This wastage is especially pronounced at higher speeds, where engine cooling becomes more critical. Now, Bosch may have found a way to deal with this wastage, via its newly developed water injection system for automobiles.
Dr Rolf Bulander, Chairman of the Bosch Mobility Solutions business sector and member of the board of management of Robert Bosch GmbH, explains that Bosch’s water injection system has the potential to reduce fuel consumption by up to 13 % and is especially effective during hard acceleration and high-speed driving on expressways. He also says that the technology is very useful for smaller, three- and four-cylinder engines that are typically used in many hatchbacks and small to mid-size family saloons.
In addition to boosting fuel economy, Bosch’s water injection system can also boost an engine’s power delivery, especially with turbocharged engines. Stefan Seiberth, President of the Gasoline Systems division at Bosch, explains that the basic premise behind the water injection system is simple – prevent overheating, thereby increasing the engine’s operating efficiency. In conventional engines, additional fuel is injected to help with cooling. When this ‘extra’ fuel evaporates, it helps cool down parts of the engine block. With Bosch’s water injection system, a fine mist of water is injected into the intake duct before the fuel ignites, which helps keep the engine cool without requiring extra fuel for cooling. As an added benefit, only a few 100mm of water is required for every 100km of driving, which means that the storage tank for the water injection system can be kept at a very compact size and has to be refilled only once in about 3,000km.
The water injection system is already in production and the first car to use this is the BMW M4 GTS, which is powered by a turbocharged 6-cylinder engine. It is also important to note that water injection does not come with any risk of causing rust or other damage to the engine, since no amount of water is left in the engine’s combustion chamber – every last bit evaporates before actual combustion happens inside the engine, and is expelled out from the vehicle’s exhaust system along with other exhaust gases.
According to Bosch, the company uses a port injection system which costs relatively less to manufacture, and also offers distinct technical advantages over other systems. It also makes water injection suitable for large scale production, across multiple vehicle segments. Apart from BMW, Bosch expects many other car manufacturers to adopt the use of water injection for their high-performance cars in the near future.