Hi guys
im dont normaly post in the HHO section because im working on other devices in other sections of the forum, but i still have an interest in any method to improve our way of getting better results from all our ideas.
The idea i had was to help produce more electricity to convert more water to HHO, i know you can add alternators etc but these put a direct strain on the engine sapping power, but what if you could take energy that is otherwise wasted from the engine and use this to make electricty?.
This idea has most likely being used already as its so simple and if so then nothing lost realy but if it isnt then you could gain quite allot.
The idea is to use the exhaust gasses to spin a turbo, if you remove the compressor housing and have magnets attached to the compressor wheel (very very securly) then build coils to catch the magnetism from the rotating magnets, if you collect the electricity in capacitors ( to reduce drag) then fire this at intervals through you water to get your HHO.
Remember turbo charges can spin at speeds of anything from 60,000rpm to 250,000 rpm, and this is all from expelled gas, the engine needs a certain amount of back pressure from the exhaust to function properly so maybe gutting a caterlitic converter(CAT) then introducing your turbo charger would create the back pressure lost from the CAT, there is a hell of alot of untapped power available in this method i believe.
Its a very rough discription/idea but i hope it will help you guys, if its already been used then sorry but its worth a mention just incase.
your thoughts?
Chad.
Quote from: Chad on May 18, 2008, 10:26:22 AM
....the idea is to use the exhaust gasses to spin a turbo...
This will increase the back pressure on the engine and have an effect
on fuel consumption and thermodynamic efficiency. it is not really
free energy.
On the other hand, if you were to use Peltier devices to get the heat out of
the exhaust, then this electricity could do what you want it to do.
Paul.
This is correct but!, what i have said is that you need a certain amount of back presure for the engine to run properly, a free flow exhaust from engine to tail pipe will cause engines to lose power, so what i suggest is to remove the catalytic converter wich produces a hell of alot of back pressure and replace this with the turbo generator, this will basicaly replace one back pressure item for another... so it is energy you wouldnt have in the first place, the turbo generator wont be as much of a restriction in the exhaust as the CAT so power gains will be made and the extra electricity can be put to use in HHO production.
Chad.
Maybe you could get a diesel turbo so it won't spin so fast and hook the shaft up direct drive with a GM single wire alternator to charge an isolated battery or two. Don't forget you have to run oil lines to the turbo to keep it lubed and cool.
@Chad
U r right and u r wrong.A lot of factors with back pressure.I just give u a simple example:
-drag racing machines have no muffers (what is drag race machine about? about the power!)
-airplanes have no back pressure either(just pipes there)
-sport motorbikes have free flow exhausts
so when it comes to power...backpressure is a bad thing and it robs u of HP's.Any book on car tuning and hundreds of dyno tests graphs prove it all.
Back pressure makes ur engine to pump more pressurised exhaust gases.Extra work extracted from the engine=> needs more fuel also.
Why we have mufflers?so we won't loose our ears.Drag racing machines and aeroplanes have no dB restriction so they love the concept of free pipe exhaust.First muffer plays its role as a resonator in mid range rpm's,to add
Is backpressure so bad?No,it helps in some engines to reduce power lost at low an mid range rpm's.In those ICE's valves have static valve timing(most of the cars).The problem is that simultaneously it rob u of high rpm power.So u get something for something.Lower high end efficiency vs. higher torgue at lower rpm's.Normal road car is operated at low-mid range rpm's more than high,so it makes sense to introduce some back pressure.
But again story is not so simple.Back pressure would be needed only in the first phase of the exhaust(between exhaust valve opening and BDC of the piston),here some power can be gained by having back pressure and keeping the pressure in the cilinder high to do more work.During the rest of the exhaust time(BDC to the closing of the exhaust valve) back pressure acts as a resistor to the gas flow,so engine needs to put more energy into pumping gases out of the cylinder.Again power is lost,but less than gained in phase 1,because some gases already left the cylinder nad pressure to pump against is lower than.Netto result is recuperated HP's at low rpm's and stolen HP's in the hing rpm's.BUT i saw Graphs from the dyno tests showing increased torgue through most of the rpm range when less restrictive exhaust system was placed.Also fuel savings we noted.
By this example i wished to show how one can change the characteristics of an engine when playing with backpressure levels.The sad truth is that a lot of old cars have cheapest possible exhausts.Price was a factor over calculated backpressure.as a result too restrictive exhausts ,but really cheap were placed.
If u have one of those beauties, back pressure has no positive effect as controll systems makes it obscolete:
-u have variable valve timing(honda V-TEC and some formula 1 cars)
-u have electronically controlled fuel injection timing system
Yamaha as a first came with a concept of variable back pressure exhaust named EXUP.Basically it creates the exhaust restriction (backpressure)on low rpm's.Yamaha uses it in Supersport motorbikes(fzr,yzf,r1) to reduce fuel looses and compensate for power lost due to long openig time of exhaust valve.At high rpm long exhaust time is good for power as it gives more time to "breathe".At low rpm's it opes too early, when a gas pressure is still high and could produce more power if the valve was opened later.In this case back pressure acts as a resistor to reduce the pressure drop in the cilinder even when the exhaust valve is already open.At mid-high rpm's EXUP is basically fully open and only the muffer is a restriction(again only to meet the dB levels set by law).
It is a simple example(yet,still having a problem of stealing power in second phase of exhaust) how to deal with effects of backpressure in a dynamic way.
How to use this knowledge?
Well,if u could design a turbo that works on a not too high back pressure,that would be decreasing with increasing rpm's i would agree with u that ur proposal is a good idea.Maybe small turbocharger with a waste gate controlled by rpm would do the job.At low rpm's small turbo would spin already good .At higher rpm's no overspeed of turbo would happen as more and more gas is baypassing via waste gate.Back pressure could be kept to the desired level,but at high rpm's all of the gas would have to bypass turbo.Resulting in a generator that produces best output at low rpm's.I would keep the catalysator as it is a vital part on reducing the polution!!!+ it won't change wave tuning! better solution would be to replace middle and back muffers by more open one's(turbo will take some of the power of the exhaust gases and reduce sound pulses).Turbo would come after the catalysator,not disturbing the wave tuning done to the engine in factory.
End result close to EXUP:
-recuperation of some exhaust power
-not changed low end characteristic of engine(important for gearbox fit and drievability)
-added extra top end power for (more fun ;D )
greetz,
B.
huh i reread my post and it seems it may give some bad impression that backpressure is a widely desired effect.
It is not!Especially in small every day cars an exhaust system is the first place to look for economy gain (with power as a nice present).
After installing of a less restrictive exhaust a figures of 8% fuel savings are not uncommon on a 1.2 liter engines with +5HP at the high end of rpm's.
Simple fact that most of the road cars have short exhaust times(non-race type cars) makes it clear that the benefits of backpressure in the first phase of the exhaust are very small and only in the lowest rpm range.For the remaining part of the rpm spectrum,backpressure steals economy and power.
When the car get modified cam's with longer exhaust times(more of a racer type),the backpressure can recuperate some of the lost power at a bit wider low rpm's range,yet stealing hp at higher rpm's.
Where we speak about racer types,here comes the EXUP as a good response for the needs of an engine(but variable valve timing is even better).
Further one more thing about the backpressure curve.It is proportional to the square of the engine airflow.