Hitchhikkr

1) How can using 2 parts fuel be less economical than 5 parts fuel? :1 :1 :1 You mean going less than 15.2:1 is less effecient.

2) DI engines will run a 25:1 mixture PER INJECTION not per cycle. Most of them use 2 injections per powerstroke to insure a complete burn, less NOx, quick cat light off, etc.

Tom-Guy

rawr, I used Smokey's own lingo when discussing, and further MGB did an indepth analysis of the concept using the same terminology. Don't let one chem class make you think you know it all.

Actually, cylinder pressures take a dive past 17:1, which is the common place efficiency cap.

Past stoich you have to crack the throttle open wider - cruise/operate at less of a vacuum - and thereby introduce more fuel into the cylinder in order to make "the same" power found at a closer to stoich ratio. The only benefit of targeting leaner than stoich is you don't go richer than stoich during closed loop engine operation.

jinxy

I'm serious though, I want to know what the reaction is. There's nothing with an exceptional octane rating that doesn't contain oxygen, like MTBE and ETBE, so those are out of the question. The other molecules in the gasoline aren't that large and cracking them without distilling could lead to all kinds of fun ---- being in the gas with a very low octane rating. The only thing I can think of is some how he's yielding a ---- load of cycloalkanes like benzene, toluene and xylene, which would be weird. I obviously don't know it all, but hydrocarbons are pretty simple.

Toysrme

*Because except in more extreme circomstances* typically leaning an engine boyond a 16.2:1 A/F ratio results in quickly increasing power losses. To gain back said power requires advancing the engine speed to nessecitate making the same power that was present before hand. By the time the power has equalized, the engine itself is less effecient in the process.
In the end fuel has to combust to create power. Less fuel, less power.

*How people like Toyota have been getting around it is via direct injection + alot of in-cylinder exhaust gas dilution of the mixture (making it effectively much richer than the fuel you put in it) and relatively high peak compression to try to make-up for a power loss.
Even old Honda's use to cycle from stoich to around a 20:1 A/R ratio way back in the day didn't they




















And I mis-remembered. My bad, it was 15.8 instead of 15.2.

Toysrme

Just one more way of adding weight, and loosing power. You can't create power by changing the form of energy. You loose it. IDK I never messed with a vapor gas engine, but it seems like this is just another 200mpg carb scam to me.
Just like sticking an alternator on a turbine in the exhaust. Sure you can use that "free power" to power some elextrical device, but it's not free power at all. It's a restriction that makes less power than it takes more power to drive than it does to make.





He's gaining back power by burning the vaporized gas. Ok? Why not adapt it to EFI & instad of vaporizing gas, drive a steam turbine that charges a battery as a quasi hybrid drivetrain. Weight, complexity, and losses during energy conversion.
At the end of the day even good hybrids are bearly any more effecient than anything eles of the same technology levels. The key to their gains is simply that they let you choose when & where that power conversion takes place!





I think it'd be really neat to see someone build a steam engine myself. Tho it'd probably be very, very heavy for the power output :\ Entertainment value would be pretty high tho. Like driving an old car offroad. They can't do anyhting but drive trails fast & try to slide over things to keep from getting stuck. Yet they're barrles of fun.

Hitchhikkr

I understood what you meant, but the way you said it sounded wrong. Using more fuel cant be for all intents "economical" in the sense of the word because you are infact using more total volume of fuel.
^^^my point.

[quote=Toysrme ]
*How people like Toyota have been getting around it is via direct injection + alot of in-cylinder exhaust gas dilution of the mixture (making it effectively much richer than the fuel you put in it) and relatively high peak compression to try to make-up for a power loss.
[quote]

Most of what your talking about here has to do with how they handle their varible valve timing, to create an "EGR effect" and what it boils down to is that your still only getting a 15:1 afr despite how much fuel the injectors spray. Trust me, I could damn near write a paper on Direct Injection at this point.

What do you consider an "old honda" btw? are you talking about the failed flame front ignition ----?

+100

Tom-Guy

Search for "Mean Gringo Bob" and dark side tuning. He ranted several dozen different places about it. MGB is what happens when people like you and I don't get our pee pees sucked regular-like.




That's a pretty broad statement. I disagree.


Agree.


If you mean closed loop operation, no. If you mean the CVCC aka stratified combustion head design that various other automakers copied, yes.



















Disagree. Stealth316 has a lot of tech I disagree with.

HondaTuner

*machine

Toysrme

jd I've seen similar charts in automotive textbooks. In my old T-Ten books, and a generic automotive book downstairs. that's simply the first one google image threw at me that looked about right.

ya i had to look it up, but that economy vtech d15b did the lean burn. http://en.wikipedia.org/wiki/Lean_burn

jinxy

all i found was him ranting about guns and ranting about some Turkish kid. everything else is dead.