Trying to predict the future is a tough business, but over the decades many a car maker has taken the bait. In 1981, Mercedes presented its Auto 2000 both as a way to meet a Government program, and to show its prowess in propulsion systems as well as aerodynamics. Fortunately, and perhaps Mercedes-typical for the times, they didn’t create a wild, spacey thing to predict future design whims. Instead, it was more an exercise in engineering than design, as that Plexiglass tail makes all too obvious. Under the hood were three different propulsion systems: Did any of them accurately predict the future?
Its aerodynamic CD of 0.28 was excellent for the times. Interestingly enough, the new-for 2001 W203 S-Class came in with a very similar CD of 0.27. Still, it didn’t exactly need such drastic measures as that aero-tail. Certainly, that wouldn’t fly on an S-Class in 2000.
One of the engine choices was a 3.8-liter V8 with cylinder deactivation. The 2001 W220-body S600’s V12 engine also offered that technology under the name of Active Cylinder Control (ACC). Other manufacturers have since taken up such technology, although not nearly so much as you might have expected.
The second engine was a 3.3-liter, dual-turbo diesel six whose horsepower figures are not given. Although not yet a direct-injection six, its performance was more than adequate, delivering7.5 L/100 km (31.3 mpg) at 120 kmh (75 mph). The W220 offered (but not in the U.S.) a 3.2-liter, 197-hp turbo-diesel six that probably yielded comparable fuel economy.
The third engine was a gas turbine about which little detailed information is available. As we know, turbines have not played any actual role in powering post-2000 cars. What Mercedes failed to predict were hybrid systems, as well as fuel cells which, of course, remain (perpetually) a few years off.
All in all, not a bad record for crystal balling.
Get rid of that hatchback kamback tail and it actually comes very close to the design of the late 80s early 90s Mercedes.
I like it just the way it is though. 😛
My guess is that the sheet metal was pretty closely based off of the W126, which had already been around for 2 years in 1979 (and influenced MB styling right up to the intro of the W140 and R129 in the early nineties. That’d explain the resemblance. Actually, it looks like the taillights were lifted directly from a W126 S-Class.
Lineage aside, I really like this design. Maybe it’s because I have a thing for full-size hatchbacks, but fix the C-pillar a little, adjust the ride height up a bit (is this on airbag suspension maybe), and it’s pretty near perfect.
Principaldan: at first sight, I thought you had someone Photoshop your early 80’s A body, then I saw the Mercedes back end…
Is there an engineering-based reason why cylinder deactivation never took off? Is it just an NVH issue? I’d love it if I could turn off 3 cylinders on a Civic and putter around at 35 hp/60 mph on my commute.
Now, I’m speaking as a former shade-tree mechanic, not as an engineer. But my educated guess is:
Vibration played a factor; but so too did the mechanical complexities of it all. It wasn’t the moving parts, but that moving parts had to be coupled and uncoupled deep in the engine, using electronic controls in an abusive environment. And do so regularly.
And what do you GET from that? Drag from moving parts, remains constant; all the pistons and associated engine systems keep on turning. And temperature suddenly becomes VERY unequal; there’s more metallurgical stress there. The block goes from being evenly heated one way to sudden UNEVEN temperature distribution; and BACK TO the original system.
And of course, as you note, the uneven running of a partly-inoperative engine.
I followed this concept from 1975 when Eaton first tried it with a Ford 300 six. Even at the beginning, although savings were noted, they were not spectacular. In the end, with Ford and then Cadillac giving up on it, it all suggests it was a dead-end concept with costs exceeding benefits.
Have you forgotten that variable displacement/displacement on demand has been used (is being used) extensively on GM V8s, the Chrysler Hemi V8 and Honda’s V6 in the past ten years??? Tell them it’s dead-end.
Wasn’t aware of that.
I quit reading the buff-books about fifteen or so years ago…not an excuse, just saying. I’m now more interested in automotive PAST than hype of the PRESENT.
As for the cylinder-decouplings: I thought the 8/6/4 buried that in the cesspool I thought it well belonged. How they’re doing it today…I do not know.
The obstacles still remain. Keep in mind, I’m not talking about varying valve timing; that’s another issue.
They never “decoupled and coupled moving parts deep in the engine”. That really would have been a nightmare. Sounds like you weren’t reading the buff books in 1981 either 🙂
The technology (from the beginning) depends on deactivating the valves, so that the “dead” cylinders aren’t working hard as air pumps. But the primary engine parts are still turning and reciprocating away. Deactivating valves really isn’t that hard (nowadays), as is deactivating the fuel injection to those cylinders. It’s actually a pretty simple technology; GM was very close then (as usual). It just needed a bit more refinement and reliability (as usual).
On the 300 six, IIRC, the lifters were modified at the hydraulic tappet. On the Ford 4-to-8 prototype, the exhaust rocker was lifted or disconnected by computer control.
Not “deep in the engine,” true; but immersed in hot oil; heat; all the good stuff that doesn’t bode well for soldiered joints or silicon chips.
By “decoupled” I meant “no longer part of the power source.” Of course the pistons went on boing-boing-boing…that was part of the difficulty of the concept.
Pistons in cylinders working as air springs pump no air and thus cost no energy; true; but they also retain all the drag, all the weight…and the cylinder walls rapidly cool to the temperature of the coolant, which is drastically cooler than the inner surface of a working cylinder. Which means contraction and changes in wear and friction.
As someone with an automotive background, I’ll add my ideas. Electronics can be a nightmare and I have consistently observed that the Consumer’s Reports ratings were almost exactly mirrored by what I saw driving in the door. In today’s market, for any car less than ten years old, just but something “better than average” and you’ll get yourself a very nice used ride indeed. A V-6 Fusion used, for example, would make a great daily driver for like $10k.
Any car made in the last ten years, although some brands are worse than others, is a very good car. They will reliably go 160,000 km without doing more than oil changes. They have loads of electronics and what is really surprising is how reliable most of this is. If good electrics are your priority, then Honda and Toyota are the way to go. They are amazingly robust cars, especially the higher end stuff like the Camry XLE.
Cylinder deactivation is old hat now and easy with modern PCMs which pack a lot of computing power. The only reason we don’t see more if it is cost; the call for better fuel consumption still isn’t loud enough to justify the expense. Of course it’s much preferable to get them into a four-banger which is by design cheaper to build. An inline four would to ultra-rough with two cylinders off and besides, the gain from going from a V-6 to a four-banger would more than make up for the more expensive engine, a V-6 with deactivation.
There is going to be loads of new engines in our market as the CAFE laws tighten up, such as the Ford Ecoboost series. Will be interesting to see how these things stand up. I am generallt rather wary of turbos and the transmission on the Fiesta is really weird.
Not sure what you mean by “decoupling” the 4-6-8 Cadillac just stopped delivering fuel and spark to the given cylinder, the cylinder just pumps air when its down.
That’s the easy part; the valves also had to be deactivated, and stay in a closed position, so that the piston in the cylinder would act as an “air spring”, which minimized losses. If the valves had continued to operate, the pumping losses would have been much greater than the efficiency benefits.
That’s the part that Cadillac didn’t quite nail down back with the V8-6-4; they were close, and a bit more work would have undoubtedly made it more reliable. They rushed it before it was fully developed, a hallmark of so many GM technologies: basically good, but rushed.
And – at least in the case of the Northstar, if it loses all of its coolant – the cylinders alternate in “live” or “dead” mode, to reduce the formation of hot spots in the engine. This allows the car to be driven in for service at a reducedvspped in a “limp home” mode, up to 250 miles if memory serves.
The Fail Safe cooling system modular displacement keeps the valves still opening as normal. The MDS systems that purport to save fuel deactivate the only certain cylinders IE those that have the valve control.
I know, but I was under the impression that he thought there was some sort of disconection of the piston from the rotating assembly or something.
The Cadillac V864 stopped opening the intake valve. That is why they tended to burn so much oil, the high vacuum in the deactivated cyl pulled oil past the rings. They used TBI and a distributor so they couldn’t shut off fuel or spark to a particular cylinder. The amount of fuel injected was reduced but the only reason it didn’t make it to a particular cyl was the fact that intake valve didn’t open.
Oops forgot to include the picture of the valve deactivation system.
We converted many 368 Caddys back to regular lifters as the V8-6-4 thing never really worked and the cars would buck and chug like the worst beaters you can imagine. The new for 1980 lock up torque converters made it even worse. By this point the gas price fears had disappeared anyway and I doubt the Caddy engine ever saved any fuel. Without the silly deactivation, a 368 ci Caddy was a very nice ride but not nearly as good a 425, which was one the best motors of the 1970s in my opinion. Loads of torque coupled with a THM400 makes a really nice ride.
Here is a picture of how Chyrsler does it. They deactivate the actual lifter.
Honda uses their version of “variable” valve timing. Honda doesn’t have variable valve timing like other mfgs they just choose between different cam lobes so in this it’s sort of a reverse of VTEC-e in that they switch to using a round lobe for all of the intake valves for a particular cylinder instead of just one.
As far as the uneven heating issue the pumping in the cylinder still creates some heat in that cylinder and with all the aluminum parts and the interconnected cooling passages there is not a significant difference in temps.
However there is another modular displacement system that does use that lack of combustion to it’s advantage. It is Ford’s fail safe cooling system. It just stops supplying fuel to half of the cylinders and alternating the cylinders that are deactivated. They essentially turn the engine into air cooling. The only other difference from the engines that preceded them is the switch to a cylinder head temp sensor instead of a coolant temp sensor. If the cyl head temp gets too high it shuts the engine down.
Thanks for the good explanation. I always mistakenly thought the V-8-6-4 was a similar design but marred by implementation. Good to know the details.
The first few years of GM’s DoD system had some growing pains. I’m guessing (?) they’ve worked the kinks out since then.
I don’t know much about the modern Chrysler or Honda system.
My understanding is that the main problems with the Caddy 8/6/4 system were 1)computer controlling it was too slow so the transition was very noticeable, 2)it was put in a big, heavy car so rarely had a chance to drop down to 4-cyl mode unless the car was stopped, 3)a V8 can still be balanced running with 4 cylinders but not 6 cylinders. In 6 cylinder mode the engine was unbalanced. Modern V8s such as the new Hemi only switch between 8 and 4 cylinders, not 6 cylinders.
When stopped, the 4-6-8 idled on all 8 cylinders. The modular displacement only worked when the car was moving and yeah, the 6 cylinder function was another monkey wrench for the computer.
I didn’t know that, and that seems dumb to me. Should have idled on 4 cylinders.
You’re writing your response as if it was 2005. Honda has been selling variable displacement V6’s since at least 2007. First V6-3 and now V6-4-3 are mounted in most Accord’s and Odyssey’s (Pilot’s too, I think).
My 1999 Subaru Legacy wagon with a 165hp Flat-4 seats 4 and gets around 25 mpg (or slightly less). My Dad’s 2007 Honda Odyssey has got 265hp, looks like a barn door, seats 7 and regularly gets 27mph.
Cruising at 65mph the Odyssey is in 3-cyl mode at least half the time.
Wouldn’t supercharging and or turbocharging a 1.2 liter 3 cylinder engine to the horsepower and torque level of a (for example) 2.4 liter four be easier than cylinder deactivating?
Looks like a DeLorean combined with a Citroen SM in the back, with a hint of the AMG CLK GTR in the nose. It also reminds me of the large number of Town Cars I have seen dragging their tails because of broken springs. Nothing about this really works for me, even acknowledging that it’s a 30-year-old concept car. It looks like they took every idea they could think of and threw it all together.
The front looks very close to the next S-class that came out around 1991.
Jeez, I always learn something on this site. Now I can mention cylinder de-activation without sounding like an idiot.
And I always love these kind of ‘practical’ future cars. Love the breadvan back end.
Without the hatchback kammback, from a sideview it look like a Dodge Dynasty/Chrysler New Yorker.
Barracuda! I’d like to meet the designers of this car (wagon?) and shoot them. A classic example of not taking car design seriously. OK, they’ll be built good, but being ugly has no justification. I think GM money-men erred on the side of superficial design and engineering stagnation, while Daimler money-men erred on the opposite side of engineering prowess but design stodginess. This is one of the big reasons the company is floundering now against BMW and even the upstart Audi. Once the Japanese closed the manufacturing gap, it was only a matter of time.
For a superbly designed car on the same concept done right, look no further than the Rover SD1:
Thats possibly the only time “superb” and “Rover SD1” were mentioned in the same sentence.
As with everything Rover, they were much better when actually running right and owned by somebody else. One of the main reasons for the horrible quality if these rolling disasters, other than the workers who built them didn’t give a crap, was most were company cars. A company car is a major tax break for British white collar workers and is thus a huge market. I’d wager most SD1’s went for company cars. They’d get drive a few years and given back and Rover would flog them onto their new victim, not caring too hoots that they thing was about to collapse into a rusty, non-driving heap soon after. They had their market and as long as the cars were nice new, they had the market sewn up.
This ended with the dastardly Honda (and a few others) set up shop in the UK and the leasing companies, big shock coming, bought up like four gadillion, thus busting the UK’s truly decrepit auto industry to the death it most definitely deserved.
Yeah, right. That probably explains why Honda has the UK top ten selling list covered.
Ford, Vauxhall, VW and even BMW(!). No Toyonda.
Either European buyers are really stupid, or EU has strange tariffs, or superior Japanese quality exists only in North America and Japan.
1. It’s a technical concept car, not a styling exercise – purely W126 below the belt-line, bar the front end.
2. The Rover SD1 had a cD of 0.40
All the same, it is `Auto 2000′ while the Rover is `Auto 1975′, having a cD of 0.36-0.39 in production (with poor Rover build quality of course). The M-B company was seriously lacking in vision when it put out the Auto 2000. Good engineering is not a substitute for good styling. I consider the period after W124/W126 till today as the long dark night of MB car design. Is it a wonder that polarising designs at BMW won that firm more sales than MB towards the end of this period (’81-2000), so much that now BMW is the standard others fail against? This `technical’ concept car shows the stagnation in Mercedes design more than engineering prowess.
Minor correction – the W220 is the 2000-2006 S-Class; the W203 is the 2001-2007 C-Class.
As for the “Auto 2000”, the first thing I thought of was the Honda Crosstour…
Methinks it looks like the result of unholy congress between a W126 and an ’80s Aston-Martin Lagonda.
It looks like a malformed Alfa 164.
From the side, I keep seeing a Jensen Interceptor that’s been stretched in the middle to make it a 4-door.
Am I really the only one seeing a proto-type Porsche Panamera here?
In terms of general ugliness, no.
Oh come now, it doesn’t come close to the Panamera for ugliness, but to my eye it definitely presages it form-wise
Is that one of those NASCAR Monte Carlo back windows? Did MB want to go stock car racin in the future?
I’d like to know more about whatever government program inspired these designs, since it seems that a lot of the elements found their way into production vehicles in the subsequent decades.