NITROUS OXIDE ( nos / n2o ) advice forum

Hi All

My Porsche 928 has Nikasil plated bores and I use quite a lot of Nitrous with no problems at all .....

All the best Brett

I think we pretty much singing from the same sheet there Trev, the only difference being my comments are based purely on the data given from the link, not trying to summise what happens in every situation.
I puposely didnt mention REVO's purely because of this, as i figured, had that data been posted by a WON customer, you would have known about and probably used it before it became an internet posting elsewhere. It can be assumed, rightly or wrongly that the engine data is acquired from pulsed technology or a fixed stage hit.
The points you made about the reasons for more constant delivery apart from the solenoid frequencies, where also the reasons i had in mind for the consistent density, and it is likely the 2 are very closely interlinked.
Going back to the posted data, in that instance there is some decomposition of the nitrous, but not complete. The pressure spikes on the downstroke indicate a further erratic combustion and an increasingly lean mix, this can only really be contributed to further decomposition, least in my opinion. Would be interested to hear your opinion if it differs much
Yes, turbo motors make ideal nitrous motors, but even they wouldnt handle runaway peak pressures, especially on or around TDC, high pressure increases in this area make very little torque but owing to the crank angle contribute highly to engine damage. To withstand the sort of figures we'd be looking at then we are well into the realms of nitro engines.
Total thermal decomposition prior to ignition, in our applications is very very bad, as we no longer have any control over it, so if we are reaching that level, then to move beyond it and regain control, we need to know :-
a)if the fuel is indeed acting as a catalyst, and if so by how much and then gain knowledge of the decomposition rates/temp/pressure tables. Then we could have timed injection of the fuel directly into the cylinder as per a diesel to control where the power starts
b) if the fuel is not acting as a catalyst the quantity/temp/pressure relation of the nitrous decomposition so we can have timed injection of the nitrous so again we can put the power where its needed.
Once thats mastered, the heat is the next thing we need to control, as this would be the next limiting factor of how hard an engine could be pushed

Owing to the above thinking, i personally think, as stated when you first mentioned it, that direct cylinder injection is the way forward, as this will push the boundaries the furthest whilst maintaining control and why im also willing to let you use any spare engine i have to further this along, as it undoubtedly has a magnitude of problems that come with it, some known, some not. Only time will tell if they can be completely overcome. That same technology may also be needed for something along the lines of timed water injection to combat heat, or timed nitrogen injection to help harness the forces created.
Anyway, enough for now, i need to get my thinking head off, and my spanner head on!! Lol

Steve

A brief update;

Since my last post I've been working with another foreign customer who wants my help to create an TO RUN ON NITROUS ONLY.
HIS research indicates that it should be possible to make an existing engine design do that, once the normal combustion process of gasoline has generated as near as possible the required conditions to do so.

By coincidence this marries very well with my current project - the Semi Sealed Induction System, so I'll be killing 4 birds with one stone with that project now;
1) Taking 'normal' nitrous injection to a whole new level of technology
2) Determining if nitrous dissociates prior to normal spark ignition FOR CERTAIN - as this guy (the SECOND TO SAY SO), is claiming IT WILL.
3) If we PROVE that to be the case, we'll see what can be achieved using nitrous alone
4) Proving how far my thinking is in front of everyone else.

BTW this guy wants to run an engine on nitrous ONLY, because it would be the ONLY ZERO emission fuel - how BIZARRE would it be if nitrous became the fuel of the future and even more bizarrely how much money would that make me?

Personally I doubt it's a viable option for numerous practical reasons, even if it makes comparable power but I'm still going to work with the guy to try and achieve this, JUST FOR THE HELL OF IT.

One thing is certain, IF this all works out, it should PUT A STOP to Batty mouthing off that he knows more about this subject than is good for him.

You remember me emailing you about how the SSID concept gave me the horn !!

Run an engine on Nitrous only??
This has just surpassed that email Trev

You thinking about messing with the nitrous condition in the inlet tract to the point where the nitrous will release its energy as the prime mover in the cylinders ??

My 'THINKING' is this Perry;

'IF' as has been CATEGORICALLY STATED by 2 different people now, (one of which at least, I'd be very surprised to discover was wrong due to his highly informed position in an extremely well situated company), the nitrous is dissociating PRIOR to ignition (at a certain level of nitrous injection, under certain conditions) and as indicated by the graphs linked to in the first post, it results in a MASSIVE increase in heat above that of fuel and air alone, then it seems to follow that at that point upwards we SHOULDN'T NEED FUEL or a spark, as long as those conditions can be sustained with those elements removed.

Now that wasn’t my original intention when I conceived of the SSIS concept but after speaking with the guy who is in to the 'green' aspects of an engine running on nitrous alone, it makes sense to extend the experimentation with the SSIS to determine 'IF' that's possible and 'IF' my 'expectations' can be realised.

'IF' I'm right and 'IF' I'm able to achieve controlled use of nitrous ONLY, I 'predict' that the existing limitations of nitrous use would be easily eclipsed, because I 'believe' that one of the main current limitations, is caused by the nitrous prematurely dissociating (prior to ignition), which causes the fuel to detonate. 'IF' we can remove ALL the fuel and just use the heat & energy created by the dissociation of nitrous, we'll have REMOVED the risk of the fuel detonating.

LET ME EMPHASIS, THIS IS ALL PURELY SPECULATIVE!!!

HOWEVER, as ALL my previous speculations have proved to be CORRECT so far, I wouldn't recommend anyone to bet against it.

Maybe Batty would like to make a £1,000 bet on the matter, because although I have nothing that I consider concrete on the outcome of this experiment at present, I am confident enough in my past record to make such a bet.

I understand the theory of the SSID being a means to trap the nitrous and fuel mix in the inlet manifold, thereby possibly creating a positive charge pressure in the inlet, which would create a supercharging effect under a carb or even in front of a throttle body in an EFI system. And with the right nitrous to fuel ratio for the engine with the SSID closed the engine would run fine on the mix.

Are you talkng about somehow affecting the nitrous charge to a point where it becomes unstable (if thats the correct term) to a point where it will expand due to chemical breakdown / decomposition and provide the motive force for the pistons? This is sounding like a diesel engine isnt it? Extreme heat and pressure causing (not combustion) but chemical breakdown of the nitrous which will make it increase in volume quite rapidly.

Have I got that right ??

Even if this doesnt work as intended, it could certainly provide some extremely usefull data for our purposes
Steve

Exactly!

Now brace yourself for some simple numpty logic and questions ??
This whole topic of using dissociation of nitrous as an engery source has got my simple brain in overload

I can see how we could liberate energy from such a process. But surely this would be at a fixed rate once the temperature and pressure conditions to promote such a reaction are reached. And I'm assuming the fixed rate of breakdown could only be maintained if the pressure and temperature could be maintained throughout this process ?

If you can reach a condition in a chamber where this reaction will occur then surely to maintain a stable reaction rate the initial conditions must be maintained. The resulting heat and possible pressure increase in this chamber must surely affect the rate of reaction?

If more heat and more pressure will exaserbate the reaction then the reaction will run away without control wont it?

I can actually see this working really well on a turbine type engine where pressure equals motive force, but can also see many drawbacks for a piston engine.
I think the biggest hurdle to overcome is going to be timing the dissociation, increasing pressure before TDC will act as a brake rather than motive force, so the reaction has to happen post TDC, sorry, the major reaction. Then the nitrogen can do its thing for us. At present using fuel, we use the combustion to control the major reaction so its timing gives the piston a push in the right direction, this now wont be the case so pressure will be the determining factor. Now just increasing the pressure and nitrous quantity will mean that the reaction will start occurring prior to TDC, and get worse as the piston approaches TDC, therefore possibly stalling the piston altogether. The nitrous would really need to be injected somewhere near TDC to get the reaction post TDC.
Another factor could also be residual heat. We know the heat generated by nitrous dissociation is very high, and the amount of pressure required will generate heat too, so will there come o point where the oxygen content actually ignites the engine components?
This certainly isnt going to be a straightforward bolt on for a petrol or even diesel engine, as i feel both of these would prove too fragile.
Looking at the logic, i feel perhaps, using just the SSID, this project is doomed to failure, as it will infact require my old favourite, the timed direct injection.But in the same breath, i also beleive we coul;d possibly gain a lot more knowledge of dissociation and nitrous use.
Then again, what do i know? And by all accounts, if nothing was ever tried, we'd know nothing.
Succeed or fail, heres to some usefull results

Steve

That was where i was coming from. So you're going to run as normal first on fuel then cut fuel when you think it may be self sustaining? Hmmmm, i think that may be more difficult initially than goin for dissociation powered from the off, only as the point where the fuel is cut must be extremely critical, get this wrong and melted pistons will be order of the day lol. I would also imagine that for race use, at the exact moment the fuel is cut, the nitrous delivery needs to increase dramatically to avoid any step down in power output.
If as you mentioned, it may require the spark to iniate the process, that could indeed be a bonus as we have good enough technology in this department. Firing voltages may need looking at to cope with pressure levels. Rim fire plugs could even be useful here, providing a larger arc front.
Now if the spark isnt required, then i beleive it will become a whole new ball game. Thats where i think it will be easier to achieve the goals by going for this from the outset rather than using normal combustion means first. Only because a piston engine designed to combust fuel will be a completely different beast to the one required here.
Either way, i will watch the reports with interest. Enjoy your challenge
Steve

Hmmm, spose to some extent it depends how you read the graphs at the start of this thread.
Agreed, dissociation occurs at some level prior to combustion. But im not so certain the detonation is caused by detonation of the fuel as opposed to flash burn caused by oxygen enrichment owing to the dissociated nitrous. An oxygen enriched combustion is much more an uncontrolled explosion with massive heat output, and much accelerated compared to normal combustion.
Its also fair to say, without full gas analysis of the combustion chamber at the points around combustion, we'll never really know for certain. But i have a feeling we will be finding out one way or another very soon lol

Steve

this thread almost makes me understand why nitrous works so well on high compression long rod engines....instead of the low compression engines that are the norm.

This thread is giving me a headache,the penalty for not being as clever as you number crunchers ...hey trev did i tell you removing the x10 filter makes my car go faster woohoo

Sorry to get all High school chemistry on this thread.. please bear with me people as this is quite a Topic to get my head around...

But am I right in stating that the breakdown of the chemical bonds -'dissociation' of N20 into its constituent parts- between the Oxygen and Nitrogen is an Exothermic reaction (releasing heat energy) which is transfered to the freed Nitrogen gas molecules causing them to become excited and expand, and it's this expansion that would give us the pressure/force down on the piston?

So this method would involve using the fuel/air conventionally to get the cylinder to a pre-determined set of conditions of (heat/pressure) and then phase in the N20..of which will break down, heat up the nitrogen (and the cylinder) allowing for further dissociation. i.e. A self sustaining reaction. You would no longer need the fuel and spark, just to flow the desired level of N20. )) That's genious.

That's about the size of it on both counts and if it's as easy to achieve, as you've made your assessment of my presentation sound, I'll be very surprised but also EXTREMELY HAPPY.

This will be totally ground breaking if you can pull it off Tev.. It will forever alter the thinking of nitrous use.
Its almost akin to a hot air engine eh?? But the primary heat source will be internal and not external..

Ok so here's where I get lost a bit... The breaking of the chemical bonds is exothermic... but the rapid expansion of liquid to gaeous N20 (through injection) causes a reduction in thermal state of the cylinders contents..?? Or is this only up to a certain level of N20 injection after which combustion temps continue to rise??

So is the exothermic energy release of the N20 into Oxygen and Nitrogen large enough to a) Heat up the Nitrogen to do work leaving B) enough thermal energy to self sustain this reaction again and c) only achievable about a certain level of injection? Otherwise the cooling effect will -act like a graphite rod in a nuclear fission reactor -stop it propagating?

It's far from a forgone conclusion and there's a long way to go to even be in a position to try this THEORY but we are making SOME progress towards being in that position, so I'll keep you all informed of any news on it as it happens.

The first step is to create the Semi Sealed Induction system, which Dave has drawn up for me in CAD and is currently being made ready to manufacture by my son-in-law Marty.
We then have 3 people eager to be the first to try the system on a Busa, so all we need then is to bring it all together on a suitable dyno with full engine analysis facilities, which so far is looking to be in Finland.