gearheads, talk to me.
DI is a clear winner in the fuel delivery category.
Sincerely doubt the existing system could even remotely handle the pressures involved...
Quote from: Artful on May 16, 2011, 10:00:48 AM
Sincerely doubt the existing system could even remotely handle the pressures involved...
the cylinders? sure they could. of course the EFI system wont, but no reason the valves and cylinders couldn't
stop trying to apply automotive technology in a motorcycle....what the hell do you think your Duc is, a VW or a Honda or something?!?!?!
I'm just thinking...
If you can drill a hole for a second plug, then why not an injector?
The only reason why not (aftermarket) DI is the development cost.
With throttle body or port injection the timing of the injector pulse is not terribly important. You can just throw the appropriate amount of fuel in the hole (at least once per combustion cycle) and it will go in the cylinder at the right time (when the valve opens). (There are efficiencies available by getting the timing correct.)
With DI the timing is very important to avoid undesirable combustion events (detonation and/or compression ignition). DI did not become economically feasible for gasoline engines until some massive improvement was mandated by increasing emissions and fuel mileage requirements.
At this time, to my somewhat limited knowledge, there are no programmable standalone ECUs that will run DI. If you just want to control fuel and spark in some way not allowed by the plug and play options, http://www.microsquirt.info/ (http://www.microsquirt.info/)
That site and the associated megasquirt site will tell you more than you ever thought you needed to know about fuel injection.
If I were to attempt it, I would probably try to adapt a mechanical injection pump from a two-cylnder diesel (as found in chinese generators). (Note: I am not a professional mechanic, just a guy with too much time on his hands)
DI would be awesome! Its a bit expensive to implement, but is getting more common all the time. To me one of the biggest advantages is being able to have huge compression without preignition (see e.g., Hyundai Sonnata with 11.3:1 or 9.5:1 and a bunch of boost). I'd guesstimate that the 1100 desmo would happily burble along at 11.5-12:1 with direct injection without troubles on regular fuel.
The biggest annoyance with a mechanical injection pump is you can't easily vary the injection timing via software. Also, at least some if not most or all diesel injection pumps rely partially on diesel fuel for lubrication. I know the Standyne pump in my old Ford relies mostly on diesel fuel for lubrication and now that the EPA has yanked the slippery stuff from the diesel its pump will die very prematurely if I don't run additive for it. Short of it is to pump gas you'd probably need to run two-stroke premix or find a pump that has its own lubrication source. I know some folks who had a small gas four stroke running direct injection and compression ignition with gasoline at a very high compression ratio (and extremely lean like a diesel). Last I heard it was far from operational, but was sorta promising in terms of hp and efficiency.
Seems like you could upgrade the timing and use a CRD-like setup. If I understand the issue correctly, the problem would be ensuring the injector timing is right. Anyone?
Nothing wrong with a little two-stroke oil... some of the good stuff even comes with soda pop mixed in! [evil]
Agreed that the lack of programmability is a drawback, but... [shiny object] Hilborn, anyone?
All right, so the trouble is not really one of practicality, it is one of expense... find someone to reverse engineer a miller-cycle ecu, and adapt the programming to two cylinders... 15:1 compression... E85...
Fuel pump
http://thmotorsports.com/apr_tuned/apr_tuned_fuel_pump/ms100017/i-222610.aspx?googlebase=MS100017-08-2007 (http://thmotorsports.com/apr_tuned/apr_tuned_fuel_pump/ms100017/i-222610.aspx?googlebase=MS100017-08-2007)
Fuel injector
http://compare.ebay.com/like/330424271714?var=bingv<yp=AllFixedPriceItemTypes&var=sbar&rvr_id=232826754631&clk_rvr_id=232826754631&crlp=1_263602_325002&UA=WVF%3F&GUID=633ff20d12a0a0e203128722fe72c762&itemid=330424271714&ff4=263602_325002 (http://compare.ebay.com/like/330424271714?var=bingv<yp=AllFixedPriceItemTypes&var=sbar&rvr_id=232826754631&clk_rvr_id=232826754631&crlp=1_263602_325002&UA=WVF%3F&GUID=633ff20d12a0a0e203128722fe72c762&itemid=330424271714&ff4=263602_325002)
Some custom fuel line
and a Bosch HPI 1.1
http://www.bosch-motorsport.de/content/language2/html/3676.htm (http://www.bosch-motorsport.de/content/language2/html/3676.htm) (which should also be able to do the ignition).
Some way of driving the fuel pump. (Add a external lobes to the camshaft drive gear and fab a mount?)
So that's an easy $3k in parts.
Plus tuning and install. It's do-able. :)
Quote from: ducatiz on May 16, 2011, 02:29:25 PM
Seems like you could upgrade the timing and use a CRD-like setup. If I understand the issue correctly, the problem would be ensuring the injector timing is right. Anyone?
The big issue with why it wouldn't work (without a lot, and I mean a lot, of tuning time) is cylinder/combustion chamber design (and cams - cam timing plays a vital role as well).
In all direct injection engines, Diesel or Otto/Carnot cycle, the piston dome, ring land are, cylinder head, and even the intake ports are all very carefully designed to get the correct flame front propagation to occur in the cylinder during a combustion event. Thousands of hours worth of simulation work, and then a ton more of dyno/vehicle work is done.
Would it be sweet? Yes. But for it to be a true direct injection engine, the fuel would have to spray directly into the cylinder - not the intake runner. I'm not a combustion engineer, but I can't imagine this working very well with the standard Ducati pistons. Additionally, that's an extra hole that's got to be drilled into the cylinder head/cylinder to allow the injector to pass through. I doubt the configuration of the engine (IE intake/exhaust port location, ring land depth, etc.) would work well with this in stock form, so plan on copious amounts of grinding/custom piston modeling as well.
Can it be done? Sure. Anything can be done with infinite $$$ and time. Practical? No. Really, power mods to our bikes aren't practical anyhow. However, I'd venture to say Ducati's working on this as we type this...it's going to become far more prevalent on OEM automobiles over the next 5 years or so, which means it's only time before it trickles down into bikes.
If someone has a spare "junker" (aka old 900??) engine lying around, you could rig something up to work...HP pump off an auto engine would likely be too heavy and need more torque to run properly at low RPM's (dunno, just saying).
Chris, that's for direct injection, compression ignition motors right? Wouldn't a direct injection spark ignition motor (like virtually all new cages and many sleds use) be considerably simpler? Also, JE will make a set of pistons to spec for a pretty reasonable cost.
The Motus motorcycle is direct injection [thumbsup]
I know a bunch of two stroke sleds and skis are direct injection, I wonder if any of the four strokes have gone that route yet? Many if not most cages are now directly injected (pretty much everything from Germany and Korea anyway and almost all of the smaller stuff from the U.S. and a hodge-podge from japan).
I think for proof of concept the special head design isn't necessary. The key to the lean burn is to spray the atomized fuel at the spark plug just before the spark event (and probably just after TDC)... which can be done if you replace one spark plug in a DS head with a high pressure injector (I think).
To answer the injection pump concern: the cam-driven pump from the VAG 2.0 shouldn't take too much torque.
I still see the actual problem not so much as a lack of parts or design, but a lack of a flexible enough ECU for a reasonable price (and a budget for R&D).
Quote from: mergatroyd on May 17, 2011, 08:44:51 AM
I still see the actual problem not so much as a lack of parts or design, but a lack of a flexible enough ECU for a reasonable price (and a budget for R&D).
.. for a one-off maybe. But if this was part of the design by the factory, there is no reason it would be significantly more expensive. Is there?
I shouldn't think so.
See bikepilot's ref to MOTUS.
I can think of no reason not to do it except for the natural conservatism in the motorcycle community. Maybe a cost-benefit analysis hasn't been done, or maybe it was done and it isn't worth the trouble until regulations and the market demand it.
Quote from: mergatroyd on May 17, 2011, 08:57:20 AM
I shouldn't think so.
See bikepilot's ref to MOTUS.
isn't the motus liquid cooled? i wonder if it's been done on an air/oil cooled engine or if that presents an issue?
There are air-cooled diesels and a diesel combustion event is much hotter than a gasoline combustion event.
It's all physics and metallurgy.
Although you never specified air-cooled desmodue :P
and it would allow a useful turbocharger (as opposed to a gargantuan one that piles on the power at 6k, a nice little one that spools early and maybe has variable vanes to maintain boost throughout the RPM range a la BMW).
Quote from: mergatroyd on May 17, 2011, 09:09:49 AM
Although you never specified air-cooled desmodue :P
and it would allow a useful turbocharger (as opposed to a gargantuan one that piles on the power at 6k, a nice little one that spools early and maybe has variable vanes to maintain boost throughout the RPM range a la BMW).
i don't know of any desmodue except the ST2 that is not air or air/oil cooled, do you? and there were only about 10,000 st2's on the road to my knowledge, in the whole world.
i think most ppl assumed it was the commoner air cooled, no?
Yeah, I know... damn lack of written tone!
I was referring to the ST2. 10k built, ever? hmmm... I like things that are rare. Is there a reference for that?
Quote from: mergatroyd on May 17, 2011, 09:15:43 AM
Yeah, I know... damn lack of written tone!
I was referring to the ST2. 10k built, ever? hmmm... I like things that are rare. Is there a reference for that?
Ducati apparently released it:
http://eastcoastducaticlub.sslpowered.com/eastcoastducaticlub.com/Forumbb3/phpBB3/viewtopic.php?f=2&t=310 (http://eastcoastducaticlub.sslpowered.com/eastcoastducaticlub.com/Forumbb3/phpBB3/viewtopic.php?f=2&t=310)
Very cool.
Now I just have to unload my other "collector" item.
Quote from: mergatroyd on May 17, 2011, 09:23:33 AM
Very cool.
Now I just have to unload my other "collector" item.
welll.. rarity doesn't make it a collector item... my 500 GTL only had about 5000 worldwide with 1400 imported to the USA. likewise, my Alazzurra is more common, but still rare.. I wouldn't call them collector items. maybe in 50 years.
More accurately, they are accumulator items.
Value is in the eye of the beholder. I wouldn't pay Barrett-Jackson prices for an ST, especially as I tend to use my cool stuff as it was intended. Cars should be driven, motorcycles should be ridden.
I just like the "one of XX with XXX,XXX miles on it and still running" concept. [moto]
I think the DI Porsche's run something insane like 1500psi for the fuel...
PM DesmoPorsche. He's wrenched on them.
Quote from: Duck-Stew on May 17, 2011, 09:53:31 AM
I think the DI Porsche's run something insane like 1500psi for the fuel...
PM DesmoPorsche. He's wrenched on them.
chresus jist, what kind of pump do they have?!
You have to run high pressure to overcome the pressure inside the cylinder, and to spray all that fuel in the much shorter time.
Quote from: mergatroyd on May 17, 2011, 09:59:28 AM
You have to run high pressure to overcome the pressure inside the cylinder, and to spray all that fuel in the much shorter time.
sure, but Porsches don't have THAT much chamber pressure.
I don't think cooling is a major issue - and it hasn't been done on liquid cooled bikes (other than Motus) either. Motos generally lag about a decade behind mainstream cages in engine technologies, especially ones of this type. With less stringent environmental regulations, smaller production volumes and much higher requirements for performance and response it makes sense. I suspect we'll gradually start to see direct injection bikes, but I don't think its going to happen quickly or anytime soon. The R&D costs will be significant and the manufacturing costs are higher as well. Not a huge amount higher, but still more and margins on bikes are extremely thin already. (ford reportedly left standard injection on the new 5.0 v8 because DI would have added $200 to production costs - dunno if its true or not, think I saw that on autoblogg, but could have been somewhere else). I think dialing in the throttle response so its just right will be more difficult, though certainly not impossible, with DI.
I don't know what sort of pressures most DI engines run, but its pretty high. I know diesels run around 2,000 psi. Pump tech varies. My old ford uses a positive-displacement rotory pump. My dad's powerstroke uses engine oil as a hydrolic fluid that's pumped to injectors. the injectors use a solinoid to pump the engine oil which acts in a compound way to squirt the fuel (so more volume of engine oil moves in an injector than fuel).
Quote from: ducatiz on May 17, 2011, 08:46:30 AM
.. for a one-off maybe. But if this was part of the design by the factory, there is no reason it would be significantly more expensive. Is there?
As discussed, the required injection pump pressure is very high. I think MotoGP rules limit the max fuel system pressure to 10 bar (very roughly 150 psi) which is way to low for direct injection. I don't know if this rule is based on legitimate technical or safety reasons or politics.
It could be that the factory does not want to mess with the high fuel pressure for safety/liability reasons. This is pure conjecture on my part though.
You've been on a roll lately with your posts - could it be that we have our own budding Erik Buell/John Britten right here on the DMF?
Bob
According to some people http://www.hcs.harvard.edu/~jus/0303/kuo.pdf (http://www.hcs.harvard.edu/~jus/0303/kuo.pdf) compression ratio of 9.8 is good for ~200 psi at 16 degrees ATDC at full load (measured at the spark event).
Plus, as you have a very small window to get fuel into the chamber...
SBK rules state the fuel pressure can be no more than .5 bar above homologated pressure.
Quote from: ducatiz on May 17, 2011, 10:03:43 AM
sure, but Porsches don't have THAT much chamber pressure.
but they run the pump off of the cam and the system does require to be at a minimum of 1100psi IIRC...
Quote from: bikepilot on May 17, 2011, 05:17:11 AM
Chris, that's for direct injection, compression ignition motors right? Wouldn't a direct injection spark ignition motor (like virtually all new cages and many sleds use) be considerably simpler? Also, JE will make a set of pistons to spec for a pretty reasonable cost.
The Motus motorcycle is direct injection [thumbsup]
I know a bunch of two stroke sleds and skis are direct injection, I wonder if any of the four strokes have gone that route yet? Many if not most cages are now directly injected (pretty much everything from Germany and Korea anyway and almost all of the smaller stuff from the U.S. and a hodge-podge from japan).
No, not just for HCCI (direct injection compression ignition otto cycle engines). This holds very true for spark ignition motors as well.
The motus motorcycle is DI because that's what the engine was designed as. Taking a non-DI engine and simply converting it isn't as simple as some are making it out to be on here. So we're all on the same page, Direct injection is the technology that sprays the fuel directly into the cylinder, unlike port injection which sprays it onto the back of the intake valve.
When an engine is designed, port or direct injection, the combustion chamber is designed to work with the fuel atomization that is going to occur because of the injector location/engine air flow/etc. The cylinder swirl/tumble is something that is carefully designed into an engine and helps assist fuel atomization on port injection engines. With direct injection you don't have that luxury, so the injector spray pattern becomes far more crucial. This is part of the reason injection pressures are so high, but it's also the reason why the injector location/combustion chamber design becomes so crucial - to ensure you get the correct flame fromt propegation across the cylinder during a combustion event.
Additional issues arise when trying to adapt this to an air-cooled engine (assuming that's what the original post was intended for). For starters, you're removing metal from the cylinder head, which acts as a crucial heat-sink for cylinder cooling. Next, injector location may be ideal in a location that has oil flowing through it, or very close to a valve which can negate cooling of that valve. There are all kinds of other things that should be considered with something like this....and again, IMO it's not worth the time unless you've got parts/$$ lying around to throw away, essentially.
Both MotoGP and WSBK rules don't allow for DI (either through limits on fuel pressure, or actually saying 'no DI allowed') , so that's one problem.
The combustion chamber shape is another.
The final one is I don't think DI actually gets you much in the way of additional performance when you ignore emissions.
Basically it's great if you want a high perf engine that still passes emissions tests. But if you don't care about emissions (coughLikeMecough) you can get high power by simply tuning your engine to be 'dirtier'.
These guys will supply OEM systems (no sales to the public), using Siemens ECUs. http://www.synerject.com/di.html (http://www.synerject.com/di.html)
After looking at some other DI engines, I don't think that the Ducati combustion chamber is inappropriately shaped (Mazda is a pent-roof shape, Ducs are hemi-ish). It might not be optimized, but it should work.
I do agree that on a naturally aspirated Otto-cycle engine, DI does not do much (if anything) for performance. It should improve efficiency (mpg) and other changes then available could improve performance.
I didn't see in the SBK rules where DI was banned, nor did I see a maximum fuel pressure like in MotoGP ???
Even a significant improvement in mpgs is a performance improvement in my book 'cause it means you can carry less fuel for the same range = less weight and more compact bike. Seems you might also be able to get some added protection from pre-ignition withing having to use crazy cams (not that I've anything against really pointy cams) or run high octane - for example the Hyndai at 11.3:1 compression runs on 87 octane and has fairly large bores and, I assume, very mild cams.
Maybe I'll do some research and write a short article on the topic or something - if anyone happens to nail down the superbike/moto gp rules as they apply to DI that'd be a great start :P
MotoGP does limit fuel pressure to 150psi, and I guess for SBK it depends on interpretation of a couple of lines from the 2011 rule book (in bold in context):
2.4.8.1 Carburation Instruments / Fuel Injection System
2.4.8.1.2 Carburation Instruments
Carburation instruments refers to throttle bodies and variable length intake tract
devices.
• The original homologated carburation instruments must be used unmodified.
• The use of optional homologated carburation instruments is not
allowed.
• The fuel injectors must be stock and unaltered from the original
specification and manufacture.
• The carburation instruments intake insulators may be modified.
• Bell mouths (including their fixing points) may be altered or replaced.
• Vacuum slides may be fixed in the open position
• Secondary throttle valves and shafts may be removed or fixed in the
open position and the electronics may be disconnected or removed
• Air and air/fuel mixture can go to the combustion chamber exclusively
through the throttle body butterflies.
Only for motorcycles homologated after the 1st of January 2010
• Electronically controlled throttle valves, known as 'ride-by-wire'
systems, may be used exclusively if the homologated model is
equipped with this system. Software may be modified but all safety
systems and procedures designed by the original manufacturer must
be maintained.
2.4.8.1.3 Air restrictors for 1200cc 2 cylinders
Definition : An air restrictor is a metallic device with a tract of constant controlled
section and which is placed in the induction duct between the carburation
instrument (throttle body) and the cylinder head. The length of the controlled
tract must be at least 3 mm. No air and/or air-fuel mixture to the engine must bypass
the restrictor. No carburation part (injector, needle, slide, etc) must extend
through the restrictor.
SBK rules:
http://www.fim-live.com/fileadmin/alfresco/Codes_et_reglements/SBK_en.pdf (http://www.fim-live.com/fileadmin/alfresco/Codes_et_reglements/SBK_en.pdf)
MotoGP rules:
http://www.fim-live.com/fileadmin/alfresco/Codes_et_reglements/6510002_GP_Regulations-Reglements_GP_4.pdf (http://www.fim-live.com/fileadmin/alfresco/Codes_et_reglements/6510002_GP_Regulations-Reglements_GP_4.pdf)