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post #21 of 23 (permalink) Old 03-16-2005, 01:20 PM
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Originally Posted by toxygen
Thank you all for your input, I currently dont pay for electricity, it is included in my rent so i may try 2v eletrolisis rig, stepped down from house current, and try to load the h2 and o2 into a tank and see what happens! I'll keep you posted.
If you released an H2/O2 mixture into an engine, eventually you'd see an ignition source somewhere along the line. The flame front would travel back into the tank, where the O2 and H2 would combine to form water. The size of the explosion would depend on the size of the tank and the pressure inside, but I wouldn't expect to survive it.

If you used separate tanks, it might work. Do not increase oxygen levels above about 3psi partial pressure (sea level oxygen concentration) and do not add much hydrogen (i.e. do not exceed about 10% of the volume of oxygen released.) If you stick to that the computer should be able to manage the mixture. I'd expect to see a small increase in fuel economy and a small decrease in CO2 emissions per kWh.

BTW if you get free electricity, do you get free natural gas? That would be a lot easier to inject, and would have about the same effect.

--bill von
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post #22 of 23 (permalink) Old 03-16-2005, 04:20 PM
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Does the Prius calculate how much fuel to inject on the next cycle based on the data from the oxygen sensor in the exhaust? If so, then the H2 and O2 should be tolerated by the computer as the car itself would compensate for any excess / shortfall in O2 by simply adjusting the amount of gas injected at the next cycle (ie riching it up or leaning it out). Or is it going to be a whole lot more complicated than that?
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post #23 of 23 (permalink) Old 03-16-2005, 05:27 PM
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Originally Posted by clett
Does the Prius calculate how much fuel to inject on the next cycle based on the data from the oxygen sensor in the exhaust?
Most cars with catalytic converters/oxygen sensors do this. It's called stochiometric operation, or complete combustion. Too little air and you get unburned hydrocarbons in your exhaust; this pollutes and gums up the catalyst. Too little fuel and you get poor combustion, less power and more nitrous oxides in the exhaust. The system tweaks the amount of fuel to maintain the ideal 14.7 air/fuel ratio.

So you can just inject extra fuel and the computer will back off the regular fuel, right? Well, not always. Most systems have expected values that should work for a given air pressure/temperature/coolant temperature etc - this is how they start, given that the oxygen sensor has to be hot to work and takes a few minutes to warm up. Even once the loop is closed, the computer may balk at having to cut fuel back to near-zero due to dumping more fuel into the line directly.

In addition, you have some other problems. If the system wants zero power from the engine, and you're feeding it fuel, it may cause trouble. The engine may continue to run with an error code, or the system may cut the ignition and cause a buildup of fuel in the intake manifold - a very bad thing. Also, changing the fuel mix significantly may cause preignition, poor combustion, or incomplete combustion.

Hence my earlier advice to try it in very small amounts. You also need some way to stop the flow when the engine is delivering below X percent of power. A fuel-flow switch might accomplish this, although you'd have to put it between the fuel manifold and the injectors. (In most modern cars, fuel is always circulating from the tank through the pump and back to the tank.) An intake manifold vacuum switch could also do it - normal pressure or high vacuum (idle) should shut off the alternative fuel, but a moderate vacuum could enable it.

--bill von
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