Ah, I wasn't aware the allowable amounts had dropped that much.
Since the diesel guys have done a lot wiith PM by using those afterburn canisters, is something similar planned for gasoline engines? It seems to me that would be a lot simpler than trying to attack it from the combustion chamber end of things.
Lemme guess: if you tell me you gotta kill me.
Jensenman wrote:
Ah, I wasn't aware the allowable amounts had dropped that much.
Since the diesel guys have done a lot wiith PM by using those afterburn canisters, is something similar planned for gasoline engines? It seems to me that would be a lot simpler than trying to attack it from the combustion chamber end of things.
Lemme guess: if you tell me you gotta kill me.
No, not you specifically....
In terms of gas DI, no, afterburners are normally not needed. I'm well under the standard without any special hardware or compromise of performance. It's more about getting the basic design right. Really, in terms of the physics, if you get a lot of PM, you are not fully using the abilities of the DI- since smoke means droplet burning, and droplet burning means that you didn't fully evaporate the fuel, thus not getting all of the benefits of DI.
I've seen some SAE papers that are concerned, but as far as I can tell, it's either selling you an air conditioner for your igloo, or just not solid homework.
Diesels will ALWAYS have an issue, since that's the general physics they work on. But there are also tricks there, like UUBER high injection pressures (like 10-20x what I work with in DI).
While PM is an issue, the leading emissions issues continue to be the old stanbys- hydrocarbon and oxides of nitrogen.
Eric
what kind of pressures is ford using in their ecoboost engines? is it similar in design/setup to the 2.3l DISI in the mazdaspeed3/6 and cx7? or is the design more like that in the BMWs?
Strizzo wrote:
what kind of pressures is ford using in their ecoboost engines? is it similar in design/setup to the 2.3l DISI in the mazdaspeed3/6 and cx7? or is the design more like that in the BMWs?
For boost, it depends. But generally under one atm of boost. No real need to go more than that, and in this case, less is more.... If you get by drift.
Injection pressure up to 2100psi (or whatever was in the article- it was correct as quoted from my boss).
In terms of design/set up, what do you mean?
The I4 DI that Mazda uses is a top injector pointing striaght down. The Ecoboost is from the side, in between the intake valves. Not sure about the BMW.
So far, reading the papers, no real leader of the two schools has really emerged. Although, IMHO, the side is better as you can still have a centrally located spark plug, but there are always compromises. With good, capable software, some of these can be gotten around.
E-
as far as design, the mazda is a side injector, and maxes out at around 1700 psi. i guess its similar to the ecoboost design.
the bmw uses, from what i've heard (on the internet, so i know its true) a top injector design, which is supposed to be better because it gives a more even spread of fuel mixture throughout the chamber. also, apparently bmw runs in closed loop at all throttle positions and loads, and targets something way high like 13.5:1 afr under full boost. apparently they run much higher (like 3000+psi) fuel pressure which apparently helps them do this. the mazda stock tuning seems to keep in the mpi mindset, and targets single digit afrs under high boost and rpm. cobb's (aftermarket) tuning targets around 12-12.5:1 and increases power with seemingly no adverse effects (i haven't put an EGT gauge on it yet, but haven't seen any knock in my logs)
so i guess what i was getting at is: what afr do you target under high load/rpm and high boost? there is some speculation in the mazda community that people could target much higher afr's and still have a safe tune that produces more power due to the charge-cooling effects of the DI. are you using an all closed loop tuning like bmw, or does the ecu switch between closed and open loop like the mazda?
one of the big issues with the mazda DISI engine has been fuel dilution of the oil, has that been much of an issue that you guys have seen in your durability testing?
I really doubt the BMW is running at 3000psi. We use the same hardware, and Bosch has a safety valve at 2500psi...
Both designs are capable of good fuel mixture. Just have to have a good model, and figure out what you really want. Both rely heavily on the piston design for some special tuning one a cold start, too.
We run closed loop all the time, too- again, we use the same Bosch parts BMW does. I can't tell you how rich we run (although I do know it... ) but it is richer than 13.5:1. Again, I doubt that BMW is really running that all the time, as you actually get more power out of 12.5:1. A lot of the fuel you put in is very related to how much spark you can run, and more important, how hot the exhaust is. Outside of WOT first and part of second gear, most of the enrichment beyond that is to keep the exhaust temps from damaging the hardware- and that goes for pretty much any engine, not just turbo DI engines.
Perhaps at the start of an accel, BMW targets 13.5:1, but by the end, more than likely, they are closer to 11:1. Peak power 12.5:1. Turbos run ok down to 11.5:1 w/o much penalty, and it's good to keep components cool (relatively speaking- keep the exhaust under 1700F).
Can't say much about the oil dilution- didn't keep too much track of that part of the testing. I know it's a big concern, and a lot of people were working on it, though.
Eric
i know what the "generally accepted" afr ranges are, but supposedly the effects of DI bend the rules a bit.
i just went back and read a few of those links, so the 3.5l TT v6 in the new lincoln is going to make 355hp from a v6, while the mustang is still making 315 from a v8? how long till the mustang GT is a TT v6?
I think Isuzu's design was a side injector with a centrally mounted spark plug. All the injector tubing etc was inside the valve covers and I never had the chance to see the inside of one of the engines. I seem to recall that it operated somewhere around 1500 PSI.
Strizzo wrote:
i know what the "generally accepted" afr ranges are, but supposedly the effects of DI bend the rules a bit.
Not that I've seen. What DI does give you is better charge cooling, so you can run more optimum spark.
But the basic physics don't change. 12.5:1 is still best for power vs. up to stoich. And richer is still better for spark. There's no real advantage for running leaner at wide open, since it's such a rare operating point, except for racers (the ones on closed circuits, not us).
The main benefit for DI is better charge cooling- and that's the one everyone is using, especially with boosting. With a great system, you can run .85 lambda, and best spark, and still not overtemp the exhaust- but it's pretty darned hard to make this work on most production cars.
The next one is stratified mixture control. Which is cool if you can run lean (which most can't in the US) for fuel economy. But this isn't at all used for high speed, high load operations- just not enough time.
Jenesen- I didn't know Isuzu did a DISI- I know they are quite good at diesel. For the most part, the first to production was Mitsubishi.
E-
(as for the Mustang, that was effectively addressed in a previous post by someone else....)
RossD
New Reader
1/15/09 1:12 p.m.
I tried searching the press releases but came up nil; Can the EcoBoost run ethanol? If so do they modulate the boost pressure depending on the percentage of ethanol to gasoline present in the fuel? My view on flexfuel vehicles today is that their engines dont take advantage of either fuel very well, with regards to hp or fuel economy, but turbocharging could/can change that.
RossD wrote:
I tried searching the press releases but came up nil; Can the EcoBoost run ethanol? If so do they modulate the boost pressure depending on the percentage of ethanol to gasoline present in the fuel? My view on flexfuel vehicles today is that their engines dont take advantage of either fuel very well, with regards to hp or fuel economy, but turbocharging could/can change that.
No, not yet. And not due to not trying.
But there are some rather nagging technical problems with DI....
Your ideas about ethanol, DI, and boosting are spot on, though. And we know it.
E-
RossD
New Reader
1/15/09 1:36 p.m.
Well thats reassuring for me. Would you care to discuss said DI problems with regards to ethanol/gasoline blended fuel? Do those problems translate over to the "average" injection systems as well? (I am curious about E85, turbos, and megasquirt; if you catch my drift. In Wisconsin, you can find E85 station in about every third town with 10k+ people.)
RossD wrote:
Well thats reassuring for me. Would you care to discuss said DI problems with regards to ethanol/gasoline blended fuel? Do those problems translate over to the "average" injection systems as well? (I am curious about E85, turbos, and megasquirt; if you catch my drift. In Wisconsin, you can find E85 station in about every third town with 10k+ people.)
Not really, but it's not a wear or componet compatability problem. But it is unique to DI and how it works.
If you are interested in running E85 turbo, I'd say go for it. You can run a little higher compression OR more aggressive spark.
Spark has to be one of the more tricky issues for MS, since few, if any, tuners have cylinder pressure transducers- which would give you direct data where best spark timing is and where knock starts. There are ways of doing it, of course, but it's not nearly as accurate.
Eric
Any chance of finding more power for my '07 F-150 with the 4.6 since its a super dog?.
kevlarcorolla wrote:
Any chance of finding more power for my '07 F-150 with the 4.6 since its a super dog?.
It is planned. And I know it's been in the news.
E-
Since press is really getting out about this, here's one that might interest youall- they took our MKS and Flex do the drag strip- http://jalopnik.com/5264270/ecoboost-goes-drag-ford-flex-lincoln-mks-hit-the-strip
I'm not sure how to search jalopnik, but we've been getting links to other articles from them about the MKS, MKT, Flex, and SHO.
Feels good to work here, sometimes.
Eric
With the new 300-hp V6 Camaro, the Oval had better put this thing in the Mustang! Even a detuned version, anything has to be better than the boat anchor 4.0 truck motor that is still in use (I think, maybe I'm wrong).
fastEddie wrote:
With the new 300-hp V6 Camaro, the Oval had better put this thing in the Mustang! Even a detuned version, anything has to be better than the boat anchor 4.0 truck motor that is still in use (I think, maybe I'm wrong).
No, it uses the 275 hp version of the Duratec 35. Sweet motor- I've been working on it, and derivatives of it for 8 or so years.
E-