Bosch WaterBoost - water injection system

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I remember a long time ago on a forum, not sure if it was here or Supraforums, a member who played with water injection in his minivan. He was getting good results from it but people were very skeptical of his claims.
Bosch has developed a factory OEM water injection system for gasoline automobile engines.
http://www.bosch-mobility-solutions.com/...ater-injection/
Among other things, they claim improved fuel efficiency and lower emissions.

I remember back when we were talking about DIY water injection systems the prevailing thought was "If this idea was worth a rat's hootus, it would have been used by OEMs by now." Well sir, the OEMs were probably developing the systems as we spoke.

Anyway, the Bosch system is fairly simple. Here's what it boils down to: A 1.5 gallon tank of demineralized water which lasts 1500 miles. This is probably easier to obtain than the Oldsmobile Turbo-Rocket fluid of their ill-fated methanol-injected turbocharged Jetfire of years past! ( Olds Jetfire article, interesting reading )
The system injects water whenever its deemed necessary. Bosch claims:
5% more horsepower
up to 13% better fuel consumption (this is huge)
4% less CO2 emissions (Of no interest to anyone other than the carbon credit cartels)

While the horsepower increase is meager, the fuel consumption reduction is compelling. And water injection will keep the engine clean and free of deposits in the combustion chamber, so it performs consistently throughout its life cycle. That is very compelling to me.

Here's a short video. I don't care for the voice narration.


Thoughts?
 
Water injection is really old tech. Makes biggest difference in forced induction setups where cooling the air charge = big gains. WWII planes with superchargers, like the P38 lightning, had water injection systems.
 
For sure, water injection is old school but now the OEMs are realy trying to economically commercialize it to their advantage. Using water injection will bring down combustion/chamber temps which allows more in-cylinder pressure and reduced NOx formation- benefiting both FE and emissions. IMO, the genial systems will use condensed water obtained from the products of combustion as the feed.
 
Originally Posted By: ammolab
Just water?. And when the whole system freezes solid over a winter night?....


As long as the system maintains a sufficient expansion area, then the freeze should not cause any damage, and once the engine warms up, after a couple minutes of operation, the water will melt pretty quickly. In the interim, the engine will just run without water injection and nobody will no any different.

Or, some smart engineer will build in some kind of electrically-managed heating system that will maintain the water temp slightly above freezing when it detects below-freezing ambient temps.
 
Originally Posted By: L_Sludger

The system injects water whenever its deemed necessary. Bosch claims:
5% more horsepower
up to 13% better fuel consumption (this is huge)


ONLY if... and I mean ONLY if - your compression is high enough to take advantage of it.

I've done a lot of work with this. Late 70's engines with 7.5:1 compression see no benefits from water injection AT ALL.

However, a high compression engine that pings like crazy on 91-93 octane can run 87 octane with a good water injection system.

What seems like a million years ago already, I rebuilt a 1969 351W (back to stock) except with a mild Crane cam.

The machine shop milled the heads .010" -.015" or so flat (now with REALLY small chambers!) and cleaned up the deck surface, about .010" - - - along with flat-tops, I was over 10:1 and didn't really know it.

I soon found out that even with 92 octane pump gas, I had to retard the timing a LOT - I was only getting about 10-11 mpg. That sucked.

There used to be a water injection kit that came with a vacuum-modulated valve (more vacuum, less flow - vacuum drops, water flow increases) and I paid about $30 or $40 for it. It WORKED!!

After I got it dialed in (lots of playing required to make these work right) I could finally get my timing back up to where it was needed for good power and economy. I ended up getting 15-16 mpg once it was all dialed in right. I quart of water only lasted about 100-150 miles, though. It was tough on the hood hinges.
 
Compression is way up in modern times as compared to the mid/late 70s due to modern ignition and fuel delivery systems. My Sonata has 11.3:1 compression and runs on 87 octane, for example.

I guess they can take the compression further with water injection...
 
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True, you're not going to find any engine sold today with a 7.5:1 compression ratio, unless maybe small OPE type small engines.

Brons2, yes most new engines use high static compression ratios but they wouldn't be able to without the use of Direct Injection (and it's cooling effect) and/or wide-range variable intake cam timing (which modifies cylinder charge pressure/dynamic compression ratio using severely retarded cam timing).
 
Originally Posted By: ammolab
Just water?. And when the whole system freezes solid over a winter night?....


I think some of the aftermarket systems use windshield washer fluid for that reason.
 
I could see that injection of water if metered just perfectly, could help with fuel economy. The turbos that run on 87 tend to run very rich under high boost to control knock. If you add a little water you could lean out the mix and potentially run even higher boost
 
SilverFusion2010, Excellent point about the 87 octane knock mitigation. I was going to make that point but hesitated.

Manufacturers are going to smaller and ever more stressed motors with turbos to squeeze a fraction of a percent better MPG to satisfy the CARB/CAFE beast. Water injection could be a crucial part of the next step of that trend.
 
If you add a little water you could lean out the mix and potentially run even higher boost
Engine technology is getting closer all the time to running at stoichiometric 100% of the time.

I remember in the 1980's when the "piston engine will be extinct by 2000".... nope, not yet!
 
True, you're not going to find any engine sold today with a 7.5:1 compression ratio, unless maybe small OPE type small engines.

Brons2, yes most new engines use high static compression ratios but they wouldn't be able to without the use of Direct Injection (and it's cooling effect) and/or wide-range variable intake cam timing (which modifies cylinder charge pressure/dynamic compression ratio using severely retarded cam timing).

Interestingly, the HEMI family (and I believe the LSx engines) have reasonably high levels of static compression, but, being pushrod, clearly can't modulate intake camshaft timing independently. The 5.7L will run on 87 octane w/10.5:1 and the 6.4L requires 91 octane w/10.9:1. These engines are port injected with large bores and interestingly shaped combustion chambers.
 
Originally Posted By: ammolab
Just water?. And when the whole system freezes solid over a winter night?....


I think some of the aftermarket systems use windshield washer fluid for that reason.
Very popular for a while in the diesel truck crowd. The cheap blue washer fluid has a lot of methanol in it so they were really playing with water/methanol injection. Huge power increases and very low EGT's were the biggest benefits, guys were seeing 100+Hp gains and nice cool EGT's.
 
Carb WW2 aircraft had a big problem with TEL gunking up the top end. Marvel mystery oil concoctions were constantly fed into the engine via top end oilers in attempts to disolve that gunk. Water injection more or less the same idea, with additional short bursts of added speed possible. The increased fuel mileage claims are extraploations made from similar short bursts of extra power. Over the long run, such mileage increases evaporate.
 
Engine technology is getting closer all the time to running at stoichiometric 100% of the time.

I remember in the 1980's when the "piston engine will be extinct by 2000".... nope, not yet!
The issue with stoichiometric 100% is pollution. The 3 bed cat works best when the fuel is toggled rich/lean
 
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