Automotive

BMW water injection system offers improved performance and fuel economy

BMW water injection system off...
BMW has turned to water injection is the search for greater fuel economy
BMW has turned to water injection is the search for greater fuel economy
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BMW has turned to water injection is the search for greater fuel economy
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BMW has turned to water injection is the search for greater fuel economy
The 1 Series prototype's system can improve fuel economy by around 8 percent
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The 1 Series prototype's system can improve fuel economy by around 8 percent
Water injection also allows more power and torque
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Water injection also allows more power and torque
The water cooling system collects water from the air conditioning system
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The water cooling system collects water from the air conditioning system
BMW has tested the water cooling system in its MotoGP safety car
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BMW has tested the water cooling system in its MotoGP safety car
Water injection allows BMW to run a higher compression ratio
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Water injection allows BMW to run a higher compression ratio
The system is currently in use on the M4 MotoGP safety car
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The system is currently in use on the M4 MotoGP safety car
Whereas the M4's system is fed by a manually refuelled tank, the 1 Series self replenishes
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Whereas the M4's system is fed by a manually refuelled tank, the 1 Series self replenishes
The system sprays a fine mist of water into the combustion chamber
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The system sprays a fine mist of water into the combustion chamber
Combustion temperatures are reduced by 25 degrees celsius
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Combustion temperatures are reduced by 25 degrees celsius
Reducing combustion temperature also reduces the thremal strain on the engine's components
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Reducing combustion temperature also reduces the thremal strain on the engine's components
Water injection reduces the risk of knock in the engine, allowing a higher compression ratio
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Water injection reduces the risk of knock in the engine, allowing a higher compression ratio
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Water and fuel aren't usually a good mix, but BMW has turned to water injection technology in its ever-continuing quest for improved fuel economy and power. Its latest 1 Series prototype is fitted with such a system to help create lower combustion temperatures, which brings fuel economy benefits of up to 8 percent on the road.

Central to the benefit of water cooling is its ability to cut down on combustion temperatures. With lower combustion temperatures comes improved economy and a reduced risk of "knock", which allows BMW to run a compression ratio of 11:1 instead of the lower 9.5:1 it usually uses in its three cylinder engine. This higher compression ratio brings about better fuel efficiency on low and medium throttle applications, contributing to the improved economy offered by a water-cooled engine.

Water injection allows BMW to run a higher compression ratio
Water injection allows BMW to run a higher compression ratio

BMW's system draws water from a small tank and sprays a fine mist into the intake manifold plenum where it evaporates, reducing combustion temperatures by around 25° C (45° F).

As well as offering instant economy and performance benefits, the lower temperatures that water cooling creates reduces the strain on everything from the engine's pistons and valves to its catalytic converter and turbocharger, potentially improving the longevity of those components.

Thanks to the earlier ignition point and the increased boost it allows, the water cooling system in the 1 Series frees up 10 percent more torque and power than offered in the standard car.

The new 1 Series tester isn't the first time BMW has fitted one of its cars with a water injection system. The BMW M4 MotoGP safety car is fitted with a similar system. Whereas the MotoGP M4 draws its water from a manually filled tank in the boot, however, BMW's latest water-cooled prototype is fitted with a water recovery system that constantly tops itself up with condensed water from the air conditioning system.

Combustion temperatures are reduced by 25 degrees celsius
Combustion temperatures are reduced by 25 degrees celsius

As is the case with the M4's system, the 1 Series drains all of the water from the system's hoses back to the freeze proof tank when the car is turned off to ensure it doesn't freeze up or cause corrosion.

BMW has not announced a timeline for full-scale production, but when the MotoGP M4 car was launched the brand said "following intense testing within the MotoGP World Championship, the water injection system will also be employed in a BMW M production model in the near future."

Source: BMW

View gallery - 12 images
22 comments
nickyhansard
It also keeps the combustion chamber spotless (steam cleaned) and as the water is heated during combustion, it expands into steam salvaging some of the usually wasted heat energy, I'm not sure how much the steam would contribute to power but I think it's probably not insignificant.

I've often wondered why this is common practise in modern vehicles. I think it's probably something to do with the perception many people have (even mechanics) that ANY water will destroy an engine.
Michael Wilson
rally racers have been doing this for years. The cooling mist sprayed into the combustion chamber cools down temps, and allows the turbo to cram in more air, thus making more power. Its not a stretch to see how this will improve fuel economy. I run an aquamist system of my own in a vehicle, but its not to save on gas. However, its been known in the racing communit for quite awhile, that mixing a small bit of ethanol in with your water does increase mpgs.
mhpr262
So what happens during that part of the year when one doesn't run the airconditioning? Which, in Germany for instance, is about nine out of twelve months? No water, no water injection?
Tonifumi
Been used in trucks for years.
Compare
It was invented in Poland by Jan Gulak many years ago not by BMW. Try to find on youtube "auto na wodę".
cvx
Old invention used in WW2 just a new usage.
Rich Fussell
My old Austin Healy Sprite always ran better on Cool moist foggy nights. Anybody that has owned an old British cars knows the benefits of water as a combustion component.
Bob Flint
Everyone should notice an increase in cool humid evenings where the maximum dew point is being reached... lost of extra zip
boomer
If it's good enough for modern jet engines and older WW2 piston engined fighters then it's certainly good enough for todays cars.Really,this is a technology that should have been in automotive use long before now...
Bob
My grandfather had a water injection system on his car in the 1950s. There was a gallon jug of water mounted inside the engine compartment with a line to one of the vacuum lines on the carburetor. He claimed it increased his gas mileage.