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Water in the intake tract adds to combustion pressure as the water droplets become vaporized and expand due to the combustion heat.
It is a non-conventional way to get more power out of an engine. One way to do it is by normal vacuum that is only allowed to suck in water droplets above a certain RPM. But that would require two water tanks. One would be lower than the intake tract and its level always maintained the same by a float controlled valve, with water fed to it from a higher tank. Since I doubt I can find something like that I am considering looking for a windshield wiper pump and a relay that switches power to it off and on. The relay would be controlled by electronic circuitry that detects RPM (I know how to do that). Yes I know that water is not ideal on oil lubricated parts but the actual amount is very small, maybe one twentieth the amount of gasoline, and having it turn on only at higher RPM means that letting the engine idle a few seconds before turning it off will dry out the parts from all water. The injection point for a vacuum controlled system would have to be between the engine and the carburetor. With a pump it could be before the carb.
Here's the best page on the subject with a way to do it that relies only on intake vacuum, not a pump:
http://www.dave-cushman.net/misc/mannject.html
Here's a forum post about both types of water injection: http://www.thumpertalk.com/topic/1011142-2-strokes-and-water-injection/
Here's a page about injecting a pipe: http://www.saltmine.org.uk/randy/h2o-injection.html
from one site on the subject:
A superb octane-improver and ancillary coolant is that oldie but goodie water injection: humidifying the combustion air.
Contrary to what would be expected from the fact that water vapour is a product of combustion, its presence before the fuel is burnt stimulates more complete burning. Several benefits, easily added to a wide variety of engines, can flow from this odd fact.
History
The essential idea was developed in the first decade of the 20th century. The original purpose was cooling. By 1910 some engines which had been water-cooled were simply produced without water-jackets after addition of 'internal cooling', as water-injection was first called.
Those engines had compression ratios around 4:1 and the phenomenon of preignition (knocking, pinking) was unknown. Later however this became themain reason for water injection, which turns out to give spectacular octane improvement, allowing CR as high as 13:1. By the end of WorldWar II many aero engines used water-injection. German versions use water-methanol mixtures, partly because straight water would freeze in winter. The Wright Cyclone, a main U.S. aero engine, tested with water and methanol-water (the two liquids being miscible in all proportions, unlike methanol & petrol), showed 50:50 best (as had the Germans). The results were summarised as "high savings in fuel cost - 52% at 100% power, decreasing to 25% at low cruise powers . . . pure water is approximately equal to fuel when used as an engine internal coolant at high power".Water gained the Corsair (flown by some Kiwi pilots in the Pacific) 350bhp on its normal maximum of 2100bhp - a 17% increase. These were supercharged engines, so the results may not translate readily to normal aspiration.
Another alcohol, infamous ethanol, was similarly mixed with water before injection, but was not as good.
When Renault attacked Formula1 with twin turbos cramming several atmospheres of boost into Gordini's1500cc V6, they readily achieved 450bhp but burned holes in pistons. Then a Kiwi mechanic recalled water-injection; a reliable 550bhp won the championship. The Saab turbo works rally car at one period had a water tank as big as the petrol tank.
Some modern gas-turbine aero engines use water-injection for maximum power at takeoff. Various naval and railway external-combustion rigs are improved by steam injection.
It is a non-conventional way to get more power out of an engine. One way to do it is by normal vacuum that is only allowed to suck in water droplets above a certain RPM. But that would require two water tanks. One would be lower than the intake tract and its level always maintained the same by a float controlled valve, with water fed to it from a higher tank. Since I doubt I can find something like that I am considering looking for a windshield wiper pump and a relay that switches power to it off and on. The relay would be controlled by electronic circuitry that detects RPM (I know how to do that). Yes I know that water is not ideal on oil lubricated parts but the actual amount is very small, maybe one twentieth the amount of gasoline, and having it turn on only at higher RPM means that letting the engine idle a few seconds before turning it off will dry out the parts from all water. The injection point for a vacuum controlled system would have to be between the engine and the carburetor. With a pump it could be before the carb.
Here's the best page on the subject with a way to do it that relies only on intake vacuum, not a pump:
http://www.dave-cushman.net/misc/mannject.html
Here's a forum post about both types of water injection: http://www.thumpertalk.com/topic/1011142-2-strokes-and-water-injection/
Here's a page about injecting a pipe: http://www.saltmine.org.uk/randy/h2o-injection.html
from one site on the subject:
A superb octane-improver and ancillary coolant is that oldie but goodie water injection: humidifying the combustion air.
Contrary to what would be expected from the fact that water vapour is a product of combustion, its presence before the fuel is burnt stimulates more complete burning. Several benefits, easily added to a wide variety of engines, can flow from this odd fact.
History
The essential idea was developed in the first decade of the 20th century. The original purpose was cooling. By 1910 some engines which had been water-cooled were simply produced without water-jackets after addition of 'internal cooling', as water-injection was first called.
Those engines had compression ratios around 4:1 and the phenomenon of preignition (knocking, pinking) was unknown. Later however this became themain reason for water injection, which turns out to give spectacular octane improvement, allowing CR as high as 13:1. By the end of WorldWar II many aero engines used water-injection. German versions use water-methanol mixtures, partly because straight water would freeze in winter. The Wright Cyclone, a main U.S. aero engine, tested with water and methanol-water (the two liquids being miscible in all proportions, unlike methanol & petrol), showed 50:50 best (as had the Germans). The results were summarised as "high savings in fuel cost - 52% at 100% power, decreasing to 25% at low cruise powers . . . pure water is approximately equal to fuel when used as an engine internal coolant at high power".Water gained the Corsair (flown by some Kiwi pilots in the Pacific) 350bhp on its normal maximum of 2100bhp - a 17% increase. These were supercharged engines, so the results may not translate readily to normal aspiration.
Another alcohol, infamous ethanol, was similarly mixed with water before injection, but was not as good.
When Renault attacked Formula1 with twin turbos cramming several atmospheres of boost into Gordini's1500cc V6, they readily achieved 450bhp but burned holes in pistons. Then a Kiwi mechanic recalled water-injection; a reliable 550bhp won the championship. The Saab turbo works rally car at one period had a water tank as big as the petrol tank.
Some modern gas-turbine aero engines use water-injection for maximum power at takeoff. Various naval and railway external-combustion rigs are improved by steam injection.