Bosch Water Injection System Debuts On BMW M4 GTS

Funny how one thing leads to another. Just last week, I wrote about my unsatisfactory experience with a water injection system I purchased from JC Whitney long ago. This week comes word that a new water injection system is included in the engine for the new BMW M4 GTS, a car that is as close to a street legal race car as you can buy. Bosch says water injection helps cool the engine internally, leading to more power and higher fuel economy. Weird. That is almost exactly the way JC Whitney described its system in the catalog.

Bosch water injection system

Bosch says that most electronic fuel injection systems today are programmed to add extra fuel under hard acceleration and during high speed operation on the highway. The extra fuel is needed to control internal temperatures in the combustion chamber.

The Bosch system injects a fine mist into the intake tract just before incoming air enters the combustion chamber. The water evaporates instantly, which has a cooling affect on the cylinder head, valves, and piston crown. The company says its system is ideal for use with direct gas injection.

That means extra gasoline no longer has to be used to achieve the same amount of cooling. Bosch says its water injection system increase gas mileage by about 4%, but that number can go as high as 13% under certain conditions. The system is said to be ideal for the highly stressed turbocharged engines manufacturers are using today as they try to make more power from smaller engines.

Less gasoline used means higher fuel economy but there’s more to the story. Water is partly oxygen. A small shot of water adds available oxygen inside the combustion chamber. You engineers out there will immediately realize that adding extra oxygen is the primary role of turbochargers, so the Bosch water injection system is like having a tiny turbo mounted inside the engine. That’s where the extra power comes from.

Bosch says a 5 liter tank of distilled water should last a motorist about 3,000 miles before it needs to be replenished. If the tank runs dry, no harm will come to the engine. It simply will not have the peak power and fuel economy it is capable of. Don’t worry about the water freezing in the tank. The company says it will thaw once the heat of the engine warms up the space under the hood.

“With our water injection, we show that the combustion engine still has some tricks up its sleeve,” said Dr. Rolf Bulander, chairman of the Bosch Mobility Solutions business sector. The infernal combustion engine refuses to become obsolete. We may not be its biggest fans, but as long as it is around, more power and better fuel economy are both good things to have.

Source: Hybrid Cars   Photo credit: Bosch

Steve Hanley

Closely following the transition from internal combustion to electricity. Whether it's cars, trucks, ships, or airplanes, sustainability is the key. Please follow me on Google + and Twitter.