JohnRoberts

Ford eco boost.. What's old is new again...
« on: July 17, 2009, 05:31:34 PM »
http://media.ford.com/article_display.cfm?article_id=27455

new Ford concept looks strangely similar to old Ford concept.   http://en.wikipedia.org/wiki/Ford_Mustang_SVO

FWIW the old version was complained about for lousy low RPM torque, so they have probably added some new tuning technology that has been figured out  in the decades since.

JR

It's nice to be nice....


SSLtech

Re: Ford eco boost.. What's old is new again...
« Reply #1 on: July 17, 2009, 09:26:42 PM »
Well...

Direct injection IS nice and efficient. (doesn't half make for some filthy valves after a few thousand miles though... but don't worry, that only usually happens with turbocharg.... oh... -wait... never mind, -as you were!)

The older turbos typically deployed by manufacturers in the 1980s were frequently high-flowing, but often 'cast-iron' (felt more like cast lead!) and slower to spool than who cares what. -Top end was nice and fast, but low end was woefully under-torqued. My own Porsche is a little like this, with the accompanying lowered compression ratio making the low end feel particularly gutless by comparison to an identical normally-aspirated Porsche. -People brought up on high-torque 'muscle' cars will HATE the experience... but the top end LIGHTS UP, and propels you towards the horizon in VERY short order. Track driving calls for a two-footed tap-dance, to build boost nice and early for corners with a quick apex; braking hard AND rolling-in the gas so that the turbine has a chance to shed some of its torpor in quicker order... FAR too much work if you're used to lots of cubic inches.

More modern tendencies are to use smaller, lighter turbines which flow a little less, but don't need homicidal amounts of 'right-foot-in-the-mat' to arouse from their slumber. -Net result is a car which 'feels' more lively, because it wakes up nice and early. -The trade-off is that it often 'bottlenecks' at high revs and high loads. My Audi is a little guilty of that. (Also direct injection, Fuel-stratified charge etc) Mind you, my lunchtime drive averaged 34MPG today, so it's nice and efficient, as well as lively.

Some Porsches are now using Variable turbine geometry to allow for a turbine which can boost effectively over a wider range from low speeds to high speeds, and still maintain a high throughput... Other manufacturers are doing it too (even American ones!), but with the twin-turbo 911, this does make for a pretty stunning engine. -The BMW 335 motor is a masterpiece of twin-turbo 'best-of-both-worlds motoring, but it comes at a premium of course.

Ford are doing the right thing in several ways... first they're using lots of twin-clutch dual-shift transmissions. They're also using turbocharged direct-injected gasoline motors. -Before long, they'll be part of Porsche/VolksWagon/Audi! (they already employ J. Mays; one of VW's most iconic designers...) I don't know much about the concept shown above, but my daily-drive Audi has much of that technology, and it's the reason WHY I bought it.

Ford may be a little later to the party than a few of the European and Japanese manufacturers, but GM and Chrysler are still in the shower and wondering how to get there.

Keith
« Last Edit: July 18, 2009, 12:42:50 PM by SSLtech »
"A waist is a terrible thing to mind"
Quote from: PRR
Ah, but that was 1999; we don't party like that any more.

JohnRoberts

Re: Ford eco boost.. What's old is new again...
« Reply #2 on: July 17, 2009, 10:48:33 PM »
Ford blew their opportunity in the '60's. I interviewed with them for a co-op job and they blew me off....  those losers. 8)

I am slowly coming around to turbocharging...  I put a Vortech blower on my mustang ('93 cobra)  and that was serious fun... but in the context of  economy "and" go fast, what is needed IMO is a turbo with a lossy profile at low rpm and a lot of mass (inertia).  At low RPM economy driving the turbo is pretty much out of the picture. At slightly higher rpm the turbo grips the exhaust flow and spins up... With enough inertia it will will hold pressure between gears...

Admittedly this doesn't deliver passing power without some anticipation, but for everything else good economy and good power when asked for. Emergency braking is  more often needed than emergency acceleration. Boys who want to go fast to impress can downshift and spin it up in a few seconds.

I notice that since I put a better rear end gear ratio in my current ride it has a lot more punch up around 100 MPH, but no noticeable difference in the lower gears.  The gear ratio will do enough of the work in lower gears. The turbo boost just needs to be really happening for the higher gears.

In any adequately over powered chassis we don't need more horsepower in low gears.

JR

It's nice to be nice....

PRR

Re: Ford eco boost.. What's old is new again...
« Reply #3 on: July 18, 2009, 03:03:54 AM »
> looks strangely similar to old

Uh.... "direct injection" on Ford spark-engines is NOT old, not trivial.

You try to force fuel against compression pressure.

Yeah, the Diesel boys have done it since Ford was young, but it nearly killed Rudolf, and is still a large part of the price-premium for a Diesel.

I'm not so sure what the advantage is, except that it reduces blow-over during valve overlap.

AHHH.... reduced pre-ignition, lower octane demand.

Fancy tricks can allow a turbo to build some boost at low RPM without blowing the heads off (or getting in the way) at high RPM. A lot of traditional turbo thinking can be bent if you design every part to work together, don't just turbo an existing mill without brains.

FWIW: in the 1960s I sketched engines of this HP/CID ratio, it's not hard to do at a single high RPM. But the low-end torque would either suffer or self-destruct... the controls were not there yet. I'm not -sure- they are here yet-- my 2002 gets into a mode where a relay in the footwell chatters and then the O2 sensor quits. The kind of odd bug that does not get found in testing.

we don't need more horsepower in low gears.

"at low MPH".

Up to ~~35MPH, my 2WD econo-sedan is entirely traction-limited. Blowing go-juice into it would not improve the 0-30 times.

First Gear is usually scaled for nearly 0.5Gee, roughly wheel-spin on a 2WD car. This is roughly true for any power/weight ratio car; all that higher Horsepower gives you is the ability to drag First to a higher MPH.

Re: Ford eco boost.. What's old is new again...
« Reply #4 on: July 18, 2009, 07:51:26 AM »
Lancia had a technique for obviating turbo lag on their '80s rally cars

Lag on a 930 is legendary. Is that what you drive, Keith?  

 ;D
Prepare yourself. You are about to become the voice of Interplanetary Parliament.

SSLtech

Re: Ford eco boost.. What's old is new again...
« Reply #5 on: July 18, 2009, 10:42:53 AM »
Super AND turbo? -That's not uncommon these days. -Volkswagon does it in tiny engines for cars like the Polo and lupo, I'm pretty sure. -It should be mentioned that we don't get the miniatures over here, where the smallest VW sold is the Golf, which is considered a 'small' car, (unlike Europe, where the 5-door Golf is seen as a perfectly acceptable full-size family vehicle). It's been out for a few years now, but -again- this year, won international engine of the year. It doesn't KEEP the turbo awake, so there's still a 'kink' in the boost profile, but it does squeeze prodigious numbers from an otherwise tiny lump.

My weekend toy isn't a 930, but instead the 'cup' version of the 951... a little quicker than the 930, but only marginally. Far better balanced however, although air-cooled purists sometimes scoff at them while they're parked (it's hard to scoff from the rear-view mirror, or -more commonly- a hedge! ;) ) . Lag is comparable, but the 'push' from the seatback once it wakes up (above 3200RPM) has to be felt to be appreciated. The slight 'gutlessness' below boost threshold (well, 'slight may be understating it!) makes the boost SO much more stunning by virtue of direct contrast! It's known as the '951S', which has a LARGER hotside on the turbo, resulting in even SLOWER wake-up, but even LARGER payoff at the top end. It runs at full boost for approx 80% pf the track distance at Sebring, and returns 5.5MPG on 105 octane [(R+M)/2].

The Audi motor is direct-injection spark, but they've had to sacrifice one valve per cylinder to make it happen. They grew it from their old 5-valve-per chamber motor (which flowed wonderfully, incidentally) and they gave the center-top 'nail-hole' over to the injection system.

My last car, I also bolted a blower on, but it was a positive-displacement type; Eaton (magnusson) as opposed to the 'nautilus' (vortech). My cousin has an Eaton on a C5 'Vette, and a colleague has the same vette with the Vortech on. Side-by-side comparison is revealing. The Vortech sound stirs the loins somewhat, and hints at what lurks beneath. At low revs, the torque from the Magnusson is the clear winner, but over 2500RPM, the Vortech blows the twin-screw completely out of the water. Driving style probably dictates which a person may prefer... a low-rev grumbler-potterer will enjoy the Magnusson, a high-rev, neck-wringing-screamer will likely prefer the Vortech. (Not that the 'Vette' is known as 'lacking' in low-grunt anyhow...)

Of course, to get the power out of the same engine block, with the same swept piston volume, the compression ratio has to be reduced, otherwise the amount of boost you can put on is seriouslty limited before detonation occurs (unless you replace the pump gasoline with a seriously expensive cocktail!) -whether by lifting the head, dropping the pistons, or some other method. This then means that at zero boost, the same volume of gasoline/air mixture gets squeezed rather less, and consequently yields rather less 'puff' after the flash.

With that in mind (and I'm certain I've sung this tune here before) I was really intrigued by SAAB's variable-displacement engine, since SAAB have been selling ONLY turbocharged cars for longer than anyone else I can think of in the US market, (i.e. a range of cars where EVERY engine is turbocharged) they chose to investigate their options. Of course, in the GM buyout 20 years ago, this was 'back-burnered' and the motor never came to fruition. -I understand that this complicates one of the simplest part of the engine equation -the block- and that the added expense is significant, but the improved economy of TRULY shrinking the engine, by both drawing in less air AND reducing the volume of the combustion chambers should be a real step forward.

Saab being sold to Koenigsegg... I still can't get my head around that. -That just sounds like the cart dragging the horse, and that never ends well... but GM would've possibly just killed it otherwise.

The direct-inject spark Audis (which I think at the moment  is ALL Audis -here in the US at least- but I'd have to research) are now sold almost exclusively in quattro (4WD with a Haldex controller and computer-intervention for distribution of torque wherever grip is highest) which helps address the grip-limits. If you're going to market yourself as a car which you can have fun in, then you have to start looking for ways to get that grip to the pavement. Combined with the DSG (torque-converter-less automatic) transmission, this means that you really can begin to speed-up the 'jackrabbit' starts, -and although these are (philosophically) the polar opposite of 'green' mentality, the fact that they have already invested that much into the technological side of the motor in the name of efficiency (stuff which Ford is announcing only now) is pretty necessary in (more politically-green) Europe, and Germany especially.

http://en.wikipedia.org/wiki/Audi_S3

Keith
« Last Edit: July 18, 2009, 08:40:55 PM by SSLtech »
"A waist is a terrible thing to mind"
Quote from: PRR
Ah, but that was 1999; we don't party like that any more.

JohnRoberts

Re: Ford eco boost.. What's old is new again...
« Reply #6 on: July 18, 2009, 11:19:30 AM »
I obviously missed the direct injection distinction.  Not sure I follow the press release explanation of benefit ("cooler/denser charge"?). I guess being able to make a lean charge locally dense will help the ignition, total cylinder temperature seems limited by same constraints, intake air, compression ratio, etc... perhaps a local temperature issue that affects flame propagation?  I guess there is a slight benefit to the fuel not picking up engine heat in the ports before the intake valves are closed.

Direct cylinder injection may be a stepping stone to next generation flex fuel diesel which may be one alternative to squeeze more life out of IC's remarkable run for general transportation, as we come full circle. 

JR
It's nice to be nice....

SSLtech

Re: Ford eco boost.. What's old is new again...
« Reply #7 on: July 18, 2009, 12:41:31 PM »
Well, direct injection allows control of charge density throughout the combustion chamber. Also, the fuel temperature itself can be controlled with things like a secondary HIGH-pressure fuel-pump, a heat exchange system, rather like the intercooler for the air part of the charge; -a primitive 'refrigerator' of sorts. -By 'pulsing' the injectors (particularly at lower revs) the fuel distribution can also be controlled throughout the chamber, which is the "stratified" part of the method. -Employing a quick computer, and applying whatever algorithms, feeding in the data from the various sensors which now thrive throughout the engine like so may parasites, significant increases in efficiency can be realized, and as a result, you can have more bounce to the ounce.

Whether you choose to enjoy more bouncing -or just use fewer ounces- is up to you, but in the end you'll likely put less Tiggers in your tank.

Don't forget also that in the past, detonation has been controlled by cooling with excess fuel, which then doesn't burn fully. It's a wasteful way to kill 'knock', but sometimes you do what you have to do. Distributed charge-density seems to be a neat tool, though many points are lost on me. You can't do it with port injection, is all I know for sure.

[Edit:] I learned a bit more here: http://en.wikipedia.org/wiki/Fuel_Stratified_Injection

What's interesting is that in super 'lean-burn' mode, it keeps the fuel charge close to the spark plug, which helps lower emissions, and keeps fuel away from the cylinder walls. -Well now I know more than I knew when I woke up this morning.

Keith
« Last Edit: July 18, 2009, 04:19:54 PM by SSLtech »
"A waist is a terrible thing to mind"
Quote from: PRR
Ah, but that was 1999; we don't party like that any more.

JohnRoberts

Re: Ford eco boost.. What's old is new again...
« Reply #8 on: July 18, 2009, 03:40:56 PM »
Yup.. I mentioned the benefit of locally dense charge to help with ignition. It's hard for the spark plug to light very lean mixes.

Another cooling consideration I didn't think of is the gas changing from liquid to vapor state "after" it's in the cylinder will absorb heat just like sweat evaporating cools our skin.

A second injector spraying some water into the combustion chamber after the fire, could mitigate detonation "and" extract a little more energy from extra steam pressure, while spraying water into the insides of an engine is fraught with reliability issues.

Detroit is much more comfortable with modest incremental changes...  From that wiki link it looks like ford developed a version of this direct injection back in the '70s, so I guess it is old again...

JR
It's nice to be nice....

SSLtech

Re: Ford eco boost.. What's old is new again...
« Reply #9 on: July 18, 2009, 04:22:03 PM »
Yes, water/methanol injection is used as a knock-suppressant for precisely that reason (latent energy removed by state-change). -It should be a gas by the time it reaches cylinder walls, never close to condensing.

Keith
"A waist is a terrible thing to mind"
Quote from: PRR
Ah, but that was 1999; we don't party like that any more.


PRR

Re: Ford eco boost.. What's old is new again...
« Reply #10 on: July 18, 2009, 09:43:54 PM »
> detonation has been controlled by cooling with excess fuel, which then doesn't burn fully. It's a wasteful way to kill 'knock', but

Historically, in sedans, it was a sweet trick. You spend 95% of time at much less than full power. For decent economy, you want a high CR; but at WOT, it knocks. But if you dump excess fuel for the 5% all-out periods, you can have your economic cruise plus good GO, and the average fuel economy for reasonable drivers averages-out decent.

Also the maximum power mixture is always over-rich. Combustion time is short. Engine air capacity is only so much. Not every glop of gas will find an air molecule. Lengthening time means fewer bangs per second and less power per pound. So where engine cost or weight is limited, as in self-propelled highway vehicles, and fuel economy is NOT profit-driven, and smoke/smog is not too strict, you always wanna run over-rich when asking for maximum power.

Note the serendipity between rich for knock-control and rich for best use of precious air capacity.

Emergency power on piston fighter aircraft could be 50% more fuel than "perfect". This is where you turn the boost up past "safe", inviting catastrophic detonation, because it seems a better bet than letting the enemy catch up with you. The engine is already as big as the airframe will stand, turning fairly high RPM (over-RPM is another path to short-term power). Boost is your only free variable, and excess fuel (or water) your main tool to avoid piston-shatter. (After such an event, the engine is supposed to be stripped and re-built; it is nearly the mode of top dragsters who must do a tear-down every 1/4 mile.)

The historic DISadvantage of direct injection is that passing a fuel/air mix over the tight turn around the valve-heads does a lot to break-up the clumps and mix air with liquid. No practical injector "atomizes" liquid fuel. And there is a balance: if fuel were truly well-mixed, it would detonate sooner. OTOH, since it is large droplets, a Diesel has "lag" which means the first part of the charge does not burn, then all burns at once. Since Diesel lag makes roughness, much work goes into better injectors for smooth sedans. Which -may- mean we no longer need to pass fuel/air mix over the valve-heads for good mixing.

> ford developed a version of this direct injection back in the '70s

Nearly everything was invented by 1920. Ford had enough cash to piddle with many different good ideas. Many of which turn out to not be so good. Or just-barely not-better.... how long did Sleeve Valves run side by side against poppet valves? The reasons the Sleeve died don't have much to do with how well it worked. The GM 2-stroke Diesel was very well developed, had a long broad production life, the concept is still common in other fields, but the GM 2-stroke has vanished from our trucks.

And every company has a comfort zone. Ford was comfortable with the shoddy MotoCrap carburetors, even as bad as they got under smog-control. When smog laws tightened, they put a solenoid on the metering pin and a relay-rack on the rocker cover... as comfortable as they could get away with.

SSLtech

Re: Ford eco boost.. What's old is new again...
« Reply #11 on: July 20, 2009, 02:12:31 PM »
@PRR:

-I think last time sleeve valves (or perhaps the 'silent knight' motor) were brought up by me, you ended up cursing my name...

-Maybe we should leave it here for now.  ;) -Although (as ever) I love reading the concise summaries. -Delicious!

Keith
« Last Edit: July 20, 2009, 02:14:13 PM by SSLtech »
"A waist is a terrible thing to mind"
Quote from: PRR
Ah, but that was 1999; we don't party like that any more.

PRR

Re: Ford eco boost.. What's old is new again...
« Reply #12 on: July 20, 2009, 02:42:58 PM »
you ended up cursing my name...

Won't happen again; not on this topic. The $23 is already gone, and not really regretted. The RR Crecy project and engine is a fascinating romp through tech-history.



 

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