Hydrostatic Lock - Water inside the engine Hi,
The following is an excerpt from the site
"http://www.car-forums.com/archive/t8933.html"
Its an interesting write up on Hydrostatic locks... It describes what
could happen if we go thru water thats high enough to get sucked into the air intake.
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"Water lock" is the familiar term for the condition known as hydrostatic lock. As referenced in your question, it occurs when water is ingested by the engine in a certain quantity. The specific quantity necessary varies by engine. The problem is one of basic physics -- liquids are non-compressible. Water, of course, is a liquid.
Your engine is a four-stroke-cycle engine. The four "strokes" are intake, compression, power, and exhaust. Note that compression directly follows intake. The intake stroke occurs during (generally) downward movement with the intake valve open. This causes an air-gas mixture to be drawn into the cylinder. At the bottom of the intake stroke, the cylinder volume above the piston is at its greatest. During the compression stroke, the piston moves upward, reducing the cylinder volume above the piston until the piston reaches its upper travel limit. At this point, the cylinder volume is at its smallest. Under normal conditions, the air-fuel mixture is basically gaseous in nature and is therefore compressible. But... what happens if the cylinder is contains liquid instead of vapor? In this case, at the point when the cylinder volume is reduced to where it is approximately the same as the volume of liquid in the cylinder, the piston will no longer be able to move upward. This is the "lock" point.
Depending upon specifics of operating conditions, engine design, and general engine health, this sudden stopping of the piston by a non-compressible mass can cause damage such as a broken piston, bent or broken connrod, shattering of engine castings, or even breakage of the crankshaft.
As to the question of how much water is needed? Not much -- when the engine ingests into any single cylinder a volume of water greater than the cylinder volume above the piston at TDC, the piston in that cylinder will be stopped on its compression stroke when the cylinder volume above the piston matches the volume of ingested liquid. The smaller the engine (displacement), the less liquid is needed to get to this point. That amount can be roughly calculated for any given engine, so long as the bore, stroke, and compression ratio are known.
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My question....
The air intake of the diesel engine in my contessa is placed pretty low down behind the right headlight. As a result, I am afraid of the possibility of it sucking in water with the air when I travel through submerged areas.. and there are a lot of them on my way to work... Marol is among the worst!!!
Now in the case of a petrol engine, assuming I did not break anything... I could just remove all the spark plugs and crank the engine. This would eject all the water out of the cylinders. A lil spray of WD40 into each cylinder, put the plugs back in and I could drive my vehicle back home or to the garage.
Diesels don't have any spark plugs.... so... is there any way that we can get the water out of a diesel engine without having to take the head off ???
What about the glow plugs... has anyone ever replaced them ? if we remove them, does it open into the cylinder chamber ? and how easy is it to get them out ?
Regards,
Ashley |