PDA

View Full Version : Controlling Fuel Pressure



chevymike
02-14-2011, 01:08 AM
Hello guys I'm new here I have a good idea I think yall will love it. This post will be long, so I apologize….

I first want to give my story then my ideas. I ran across HHO videos on youtube thinking it was b.s.. This all changed when I saw a truck running on pure hydrogen at a car show. They started her up on gasoline and switched over to hydrogen, no tuning, just idling with enough calculated hydrogen. Hooked. This changed the way I though about the subject. I am finishing up my biochemistry degree and have been working on engines for a long time and been custom tuning for a year or two. One of my vehicles is a supercharged 4.3L truck. The supercharger broke and I'm having a small coolant leak in the intake manifold so work is to be done this spring/summer. I'm thinking of selling a few nitrous kits laying around and stashing the supercharger for now and starting this HHO deal.

What attracts me to HHO - alternative hydrogen (obviously), cheap fuel (water/electrolyte/electricity), and the ability to run it in the bed of my pickup off my alternator, creating hydrogen as it is running = no compressed hydrogen tanks ready to kill me and everyone else. Just a fun boom if things go wrong, maybe lose an eye but not die. But of course yall are into these things too.

This is what I'm thinking, I'll need help with recommendations for all this HHO kit business. What I want to do is run x amount of HHO from a serious kit, not a silly one...a real deal. I'll learn all the tricks and bells and whistles from yall. I'm going to invest in a hoffman apparatus and measure the exact amount of hydrogen per given time being made from the HHO kit (have slight paranoia and some ADD in there I should be studying for a biosynthesis test in two days but I’ll make an A anyway) Convert this volume/time into the energy equivalent of gasoline in gph. I work in an organic chemistry lab so I may have access to equipment that could separate and measure the hydrogen without buying my own junk. Already have a fuel pressure gauge installed in the truck and an air fuel ratio gauge, would need a fuel flow gauge in gph to convert energy equivalents.

I will take the gph of a given average fuel flow at an rpm, say my cruising rpm on the freeway maybe 2000-2200. Subtract from this the amount of hydrogen energy (in terms of gasoline gal/hr) that the HHO kit will generate per given time. I would then find how much fuel pressure decrease from stock (stock is 58-59psi currently) would be needed to allow for the HHO hydrogen energy to compensate and 'take over' the absence of gasoline. Using HPtuners I can tune against the stoichiometric air fuel ratio of gasoline at 14.7, so the computer is not adding fuel to the mixture and effectively disabling the problem of AFR enrichment. I will need to modify the fuel lines, and install an adjustable fuel pressure regulator (FPR) on the line before my fuel pressure gauge. It will make a small loop. I have used fuel solenoids from nitrous kits to block the fuel flow on one side of the fuel loop, forcing it via dash mounted switch through the fuel pressure regulator whose pressure drop will be set based on previous said calculations...(when the solenoid is off -free flow- the fuel will automatically go through it as you would drive normally, it will allow for more fuel pressure when open than the regulator side of the loop). If the solenoid ever breaks?who cares it will just add more fuel and it'll be richer = nothing breaks. If it sticks, I may have problems… but it won’t. Before this solenoid is switched on, I would need to turn on and apply the HHO gas kit deal which I will have on operation by switches (not on all the time). Those fuel pressure drop calculations from before will err on the rich side of AFR. Hit cruising rpm on the highway, flip the fuel solenoid on -block fuel & drop pressure through FPR- and the engine should stutter and try to stall, then come back running through a narrow cruising rpm band. The idea here is to get the amount of fuel exact so I am not wasting either gasoline or hydrogen. This would be very hard to tune with variable rpms, and especially at idle or above peak cylinder pressure or when pressures rise 2500rpm+ (I do this stuff).

Depending on how much hydrogen is being shoved in and how much gas is cut, it could be very profitable in terms of gas mileage, it costs 80$/tank per week. My mileage is 80% highway. If I could cut that even 20% on the highway, save 12 bucks a week. If I could cut that to 50% (which means my fuel pressure would need to be around 28 psi :eek: on the HHO) then I could save 35 bucks a week and the kit might start paying for itself. If I could cut it even more, which then I get into trouble with detonation closer to peak cylinder pressure, then I could pay for a tank of gas every two weeks. Which would be freaking awesome and insane to say the least :cool: Even if I see a few mpg increase, at least the $ wasn't going to nitrous and go fast candy.

Btw my truck's MAF is disabled until inspection time rolls around each year, and I tune my own MAP sensor parameters so those trickeries won't work, I'll have to tune myself. I think yall also have fancy throttle/tps type progressive controllers, will look into those, flashback arrestor, pwm, and all the goodies. Thanks for reading suggestions please!! Give me insight ya'll have done this before. I will have lots of questions once the time comes! I’m stoked…

chevymike
02-14-2011, 07:34 AM
http://www.youtube.com/user/zgymnast#p/u/0/7Dv_8ZjHujg

this guy has some videos of his last few tries. He looks pretty bummed out from it not working under load. I may have to rethink this whole thing for a while and see if it could be handled from a different or more reasonable angle. I think leaning out enough and adjusting timing while providing the right amount of h2 and oxygen (in oxyhydrogen) without ambient air could very well power the car with a certain amount of gasoline from the injectors, it would also be running lean and possibly need a small generator. And it could only be done at a certain RPM effectively. Running a small generator could take a few gallons per week, and if the truck is using 50% of its normal gasoline for a highway trip it could still be effective. Before I start I need to do some more thinking and looking to see if the end costs justify the means. I doubt in the end they will, it looks like its going to cost a lot of dough.

chevymike
02-14-2011, 04:21 PM
I don't think anyone is reading this so I'll keep amusing myself by typing my thought processes. There may be some points in here that would work with the practical use on a vehicle.

Oxyhydrogen works on a carburetor because the only two variables for fuel/air are throttle and manifold vacuum. I believe it to be nearly or almost impossible without some experienced tuning to do one of these kits on a vehicle with an electronically controlled throttle. Reason is the computer will adjust the throttle position if the ECM drops into limp mode or there is excessive leaning of the engine. My truck is cable controlled so thats a good start.

Carburetor - at a given RPM and load, an amount of air flow is let into the engine, it varies based on temperature and ambient pressure, but it is nearly the same at that RPM/load (load by manifold pressure). HHO works on carbs because there is no excess fuel being added, it is leaning the engine along with adding another source of fuel -hydrogen. Hydrogen's purpose I guess would be to speed up the burn and make the burn more efficient.

Fuel injection (newer style with open/closed loops by o2 sensors) - So my previous idea of cutting significant amounts of fuel to add hydrogen would not work without cutting off ambient air, and adding a generator powerful enough to mix large amounts of oxyhydrogen. Now this is not saying it wouldn't be more efficient. But I'd be betting on the efficiency of a small generator and electrolysis of water vs the amount of fuel taken out by the fuel system. The only reason this "could" be more efficient is relying on a much smaller efficient engine to create electricity to create gas "may" be more efficient than running the extra fuel in the engine, because the much smaller displacement generator engine. This idea would increase almost exponentially based on vehicle engine size and efficiency up until a point...meaning not such a good idea for a little honda 1.4L or something. And this generator thing could only improve mileage in a fuel injected engine at a specific cruising rpm on the highway, where the gas engine is most efficient and uses the least amount of throttle input.

The other fuel injection problem when taking out significant amounts of fuel would be tuning for the lower energy fuel, it would be very hard. I don't think its possible without some very technical equipment, more than just tuning software. Talking about creating your own ECM/computer. The reason being is you'd need gasoline to start the engine, and then switch over to half gas and half HHO or something, and the tune would need to be changed even running a static RPM and load. Tuning software could work here if valet mode on the software or a 'sport' or multiple modes that are able to be switched from different tunes inside the cab are offered. Problem is most vehicles that have these capabilities have electronic throttle, as previously mentioned that's no good.

Why this HHO stuff could work in the first place - alternator. As long as the charging capacity of the alternator is not exceeded, and there is not too much excessive heat, the fan only spins at one rate unless maybe you have a bentley or 200K$ car I dunno. So that parasitic loss of the fan and moving electricity..HHO takes the loss and adds it as more fuel. Of course with the price of water/electrolyte. Problem? You're gunna need a big alternator, and a small engine. I have a 140 amp alternator, but 4.3L so it may not work as well. If I switched to 180 amp alternator, and even more powerful HHO I may not see a gain in mileage as the loss at the alternator will draw more power and the HHO will replace more fuel. Again could be a wash. I think the idea here is to aim for maximum efficiency and then see what happens. I also don't believe it's going to net more than a few % more gas mileage. Nothing more than a normal person could do by making his right foot lighter on the throttle. My theory is, it will get the same mileage on a fuel injected engine without any tuning, and with improper tuning (changing voltage signals) it will get worse mileage.

So what I have to do, is take away all the variables from my fuel injection, and 'trick' my engine into thinking its a carburetor. How would one go about this? First the engine needs to be in a closed loop after warming up. No modifying the voltage to the o2 sensors like I see a lot of people doing with those VOLO things, it 'could' keep the system in open loop and then theres more variables to wrap your head around. There may be a few archaic or poorly written ECM/vehicles that those voltage regulators work very well on. You would need some higher end engine scanning/monitoring software. You would need to see at the very least injector duty percentage/cycle. To be safe monitor knock and a few other variables. The idea on my first post should work. The fuel pressure at ONE small rpm range for cruising would need to be turned down (need adjustable FPR and fuel pressure gauge), such that the same amount of gasoline in gph (need that gauge too) does not decrease. [see first post on the idea of how to do this with fuel solenoid]. A lot of testing and tuning would be needed to find the right fuel pressure drop so that the injectors are running "static" at that rpm. Note injectors cannot actually run static its just a way of saying that they're maxed out. So, max out the injectors at a given rpm by decreasing the fuel pressure. BUT make sure your fuel flow in gph has not decreased. An air fuel ratio gauge would help here to make sure the engine isn't running lean, you would need to disable some DTC (or check engine codes) so the computer doesn't take away too much timing...it can no longer add fuel in this scenario. Bad for injectors? you bet. But now it can't add fuel ;). You effectively have a carburetor based on your throttle position, rpm, and manifold pressure ONLY at that given small rpm range and when the solenoid is switched closed [again see first post]

Spark plug cooling ranges may or may not help in removing heat from the combustion chamber from running to lean. I say this because too much heat removed decreases overall mileage and efficiency, I would think 1 degree cooler than stock and losing a bit of timing would give best (and safest) results but who knows. And after all of this, it may not even add that much, if any gas mileage. I dunno I haven't tested it out and have to justify the costs before starting. What it will do is make your engine as efficient as possible and a cleaner burn. The downside being that cleaner burn comes in the form of h2o in your exhaust valves and exhaust, creating problems for the o2 sensors, cat, and exhaust over a long period of time. ...it'll rust some junk. There are engine lubricant gas additives that could be added to a tank of gas to compensate for some of the engine oxidation.

chevymike
02-15-2011, 12:41 PM
Okay so in this thread to myself, I've come to the conclusion that the amount of $$ spent on gauges and fuel lines and regulators and HHO junk, I could just switch to a carb much cheaper and have the ability to use whatever fuel saving technique I decide to chose throughout the entire RPM range instead of one small cruising range on fuel injection.

If anyone wants a better explanation on how to do this without a carburetor, I'm positive I could help you out, but it ain't gunna be cheap, and it would be used in only a narrow rpm (say a few hundred rpm with a steady throttle). You would see mileage gains cruising on the highway, at the same rate as someone with a carburetor would. But not the entire time driving. It would also be maxing out your injectors which isn't the best thing for longevity, but injectors are pretty tough to begin with.

yellowsnow
03-09-2011, 06:13 PM
fuel injected vehicle..no problem. for around $250 you can buy a stand alone fuel injector control unit. Especially needed for tuning when going to turbo. If you google Mega Squirt you'll find the one i was looking into for my turbo install.

ValerianTs
06-12-2011, 02:03 PM
mate if i did understand right... this is what you need --> [ http://www.doocu.com/pdf/read/33793 ] just the pdf. I was looking for my project, i have a sierra GT for wich no ecu chip available, so i found this, it will help you with fuel pressure. and it has the dual mode, and the cut-off is the right one if you don't want to touch your timing (reffering to the water injection + hho)