Reduction of the engine brake on a water-doped engine

[Christophe]

I create this subject to try to clear up a dark point (for me) about the operation of a water-doped engine.

Apparently several of you (including at least Zac ...) have noticed a drop in engine brake on doped engines.

If all the testimony about this strange fact (who, what, when, how, in what proportions ...) could be gathered on this subject, that would allow us to try to understand this very strange fact.

Zac, I suggest that you open the ball since you seem to have noticed this phenomenon fairly well?

[PITMIX]

Hello
So I'm stealing the show from Zac.
I discussed this with him on msn a few weeks ago and he said to me:

"Engine braking decreases when the water is acidic."

There I let Zac give the details of what he calls "acid water"

[Christophe]

Acid ... as if by chance

Ca would not join a certain explanation of a certain JR... (not the one in Dallas, eh ... the one in econology!)

Well it's still missing a little detail but for those who have a doped car ... Put a little vinegar in your bubbler to see

[PITMIX]

I am currently driving with white vinegar in the water tank. I did not notice the drop in engine brake.
But it must be said that on an automatic car and on a flat road it is not really easy to know.

[Other]

Hello,
Same observation at home, I had talked about it in several posts, but apart from those who lived little back, I remember that even
Tofotof had made this observation on a tractor.
as I don't often go to big coasts (sometimes in Charlevoix or Isle aux coudres.
But it is more particularly when I drive at 100 km / h with the engine warm and I have to slow down for an intersection, that the effect is most marked, before I braked little, just at the last minute now I have to brake earlier 'auto we have the impression which yard like a gasoline auto in 5th speed.
For long descents those who live in the mountains could tell us more.
I made the same observation on petrol engine, but much less pronounced.
It is for these reasons that I hypothesized that water doping relieves the compression stress.
In general when we are in decelleration the engine rotates quickly, so with my venturi system I draw too much water in the engine for the drop of diesel fuel injected into the engine (idle) and that the reactor has a certain thermal inertia still hot. (remains to verify cold reactor by our mountain people)
with a venturi system we are self-regulating with the amount of air that the downstream motor therefore the RPM in principle this condition follows the RPM but not necessarily the load (the case of descent or decelleration)
So too much water in these conditions, to be efficient with combustion, this water should eat all the heat of this drop of diesel fuel injected.

Andre

[Christophe]

But it must be said that on an automatic car and on a flat road it is not really easy to know.

No comment...

[Christophe]

It is for these reasons that I hypothesized that water doping relieves the compression stress.
In general when we are in decelleration the engine rotates quickly, so with my venturi system I draw too much water in the engine for the drop of diesel fuel injected into the engine (idle) and that the reactor has a certain thermal inertia still hot. (remains to verify cold reactor by our mountain people)
with a venturi system we are self-regulating with the amount of air that the downstream motor therefore the RPM in principle this condition follows the RPM but not necessarily the load (the case of descent or decelleration)
So too much water in these conditions, to be efficient with combustion, this water should eat all the heat of this drop of diesel fuel injected.

Andre

Well yes but no ... because if there is more water (vapor and even liquid) which is absorbed, on the contrary, the compression force would be higher because it would be necessary to compress more matter / gas (water liquid ends up evaporating in the engine during compression ... and it gains damn in volume by evaporating ... I have more the figure in head should find it but it is several dozen times .. .)

Where it would be possible to gain engine braking (or rather to lose) it would precisely reduce the volume of gas during compression so ... (example by pure chance ) reduce the number of gas moles or condense (therefore cool or strongly increase in pressure) a gas...(water?)

Even in the carburetor, the engine brake exists: the pumping and internal friction are much higher than the force given by the combustion of the fuel. So I don't think it's on the "explosion" side that you have to look for, but rather in the "compression" phase.

[Christophe]

The direct link is protected, so you should host the image on the forum...

[PITMIX]

It is done

[Christophe]

Mwarf at the sight of the "result", I would have done better to say nothing ...