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Channelling its inner Viking death metal chef spirit, Volvo has unleashed a concept 2-liter turbo-four delivering 450 horsepower with the help of three turbochargers.
Automotive News reports the concept Drive-E engine — developed with help from Volvo Polestar Racing — would deliver more punch per liter than other engines — such as the Bugatti Veyron’s 1,200-horsepower 8-liter quad-turbo — were it to go into production; Volvo says the engine is only a concept, and hasn’t said if it will build the engine.
Unlike old-school turbocharged engines that use exhaust to create power, the Drive-E “triple-boost” engine uses an electric turbo to drive compressed air into the other two turbos, quickly spooling up the power while eliminating lag.
49 Comments on “Volvo Goes Death Metal With Triple-Turbo Two-Liter Four...”
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I’m not an engineer, but it would seem that this configuration would potentially offer better long term reliability and performance since you could locate the electric turbos away from exhaust heat, etc.
It can’t possibly be more reliable. It sounds like the three turbos are in a series/parallel combination, the electric turbo in series with two “conventional” turbos in parallel. The electric turbo provides the motive force for the turbine sections of the conventional turbos which provide compressed air to the intake via their compressor sections. Neglecting the fact that there exist two (or possibly three) distinct turbos in the system – assuming all turbos are 99% reliable, I get that the three in series/parallel combination are 98.99% reliable. So, for this example we could easily say that there is no real-world difference in reliability to the user but I made up those reliability numbers.
The point is, three turbos in this configuration cannot be more reliable than one.
I vote to give the design to GM to get the kinks worked out first.
@Waterview,
It sounds like the electric “turbo” is actually a pump. It will be most likely an electrically driven centrifugal compressor supplying air to the turbine side of the other two compressors.
It would be quite simple. In aviation we have APUs or auxiliary power units. These are a small gas turbine that drives an air compressor to supply air to the starters, which are generally turbines as well.
The air flow is regulated through a modulating valve. This compressed air can then spin up the turbo’s compressors at when the vehicles engine exhaust flow is inadequate.
Good idea.
I agree with Al. Technically the first “turbo” is a compressor. A true turbocharger has two sections, a turbine and a compressor.
Despite what the article says, it looks like the true turbos will also be driven by exhaust gas. It’s not clear if the electric-driven compressor is then solely there to reduce turbo lag, or if those turbos will be driven by both systems sequentially or simultaneously, or will the compressor keep the turbos spinning constantly at some minimum RPM? There are a lot of unanswered design questions in my mind.
From the official release per Volvo (make of it what you will):
“The 450 hp High Performance Drive-E Powertrain Concept is based on a set of technologies not usually found in a four cylinder engine. The engine utilizes two parallel turbochargers, which are fed by an electrically powered turbo-compressor. The compressed air from this unit, rather than being fed to the cylinders, is instead used to spool up the two parallel turbochargers. Fuel is fed by a dual fuel pump working at 250 bar pressure. With this kind of power density, this triple boost installation and unique fuel system, enables a very dynamic drivability without any turbo lag, compared to a mono-turbo.”
Thanks, Cameron. That implies that the electric compressor will only be used to spool up the turbos and not drive them constantly.
The power demands of an electric turbo running continuously are way too high to support without a very big motor and battery (and of course an alternator to support it), especially with only a 12V system. At high loads for an engine this size, a ballpark number of 10 kW could be going into the compressor in a traditional turbo to provide enough air… this works out to over 700 amps with a properly functioning 12V system (actually ~14ish V in operation). You need a LOT of motor cooling and some huge copper wires for that load.
Electric turbo-compressors like this are used purely for transients, to not only force more air through the conventional turbos to help spin it up, but to get that air into the engine where it’s burned with more fuel to power the conventional turbos at a higher airflow and pressure ratio than they’d be able to achieve on their own. This way you can put a bigger conventional turbo (or set of turbos) on the engine for more peak power without losing out on responsiveness.
On the diesel side, especially heavy-duty and systems with mechanical fuel injection, these are still used in a similar way for transients, but the real benefit is to avoid the period of thick black smoke when the mechanical injection is dumping enough fuel for full boost but the turbos are still lagging.
http://www.cpowert.com/assets/CPT%20COBRA_4pp_APR2014_4print%20(2)-1.pdf
Awesome. Thanks for your post, it clears up a lot of my questions. Here’s another one, though. How quickly can the electric compressor spool up the turbos? Obviously, it must be faster than without and, as you mentioned, this system can allow running larger turbos.
I’m having a hard time thinking through the driving experience. From behind the wheel, I want more power so I depress the accelerator. Somehow that throttle deman has to map to electric compressor initiation, it has to generate enough air to spool the turbos to get air moving into the intake. It still intuitively seems like a laggy system to me. Although I can understand how it would be less laggy than the same system without the electric compressor.
Any insight? thanks again!
To 319583076:
Electric turbochargers can reach 120,000 RPM in less than .5 second, according to electric turbo manufacturer Aeristech (http://www.aeristech.co.uk/)
for 319583076
The electric motor driving the upstream turbo can spool up pretty fast having maximum torque at zero RPM.
It will spool quicker than normal turbochargers driven by exhaust whose spooling depends on an escalating exhaust/turbine/impeller/ignition/exhaust loop.
Thanks. I had assumed that all three turbos might be electric and that this would require much less cooling / lubrication than typical with traditional, exhaust-driven turbos (resulting in perhaps better performance and fewer maintenance issues).
Appreciate the insight into the APU concept – that was helpful.
Yeah, put them under the rear seat. That’s the ticket.
Yeah, it seems the author doesn’t know what a turbo is…. the electric compressor he refers to as turbo doesn’t have a…. turbine.
Makes me wonder what Immigrant Song sounds like in Chinese.
Considering Plant’s articulation, probably not that different.
Looks pretty production ready to me.Kind of shocked to see a timing belt used on a clean sheet design in this day and age, however.
Engines with timing belts run smoother than their chained counterparts, which is why Honda swears by them. When you’re working with a 4 cylinder, it needs to run as smooth as possible.
Honda dropped the timing belt from their 4 cylinders a decade ago.
This is true.
I have heard some companies are using belts submersed in oil to try to make them ‘lifetime’ timing belts, instead of using chains for NVH reasons. (Ford maybe on the 1.6 Sigma?)
Not only is a belt better for smoothness since it has a small amount of spring & dampening, but timing belts designed for wet, lubricated operation can last just as long as timing chains with lower friction & noise
I truly question whether this timing belt vs. chain thing is true. Is there honestly a noticeable difference in vibration between a chain and belt engine? I have had cars with both, and I don’t think I can tell. The 3.0VQ with chain was always smoother than my 2.8L in the Audi. My Subaru 2.2 had a belt and that was rough as hell, but my current 3.5VQ with chain is smooth. It’s louder (rev and exhaust note wise) than the 4.2 Audi or the 4.3 Lexus, but no rougher.
Edit: And the maintenance expense and worry that comes with a belt is an expensive PITA.
Not nearly as bad as having to replace a chain, and there are MANY cars out there where the chain turns out to NOT be a life of the engine part.
The trick is to at least put SOME thought into making the belt reasonably accessible, and specify realistic change intervals. Doing the belt on my Volvo 960 was a 30 minute task.
I figure that failed chain thing would be a systemic issue, where it would be well known (and I’d avoid the car used). BUT – most of my t-belt experience has been with Audis, where they do not consider the user in implementation of engine or any other design besides the interior.
Replacing a timing belt is something accepted as scheduled maintenance, while repairs to a timing chain or timing chain guide rails are a risk.
If you get hit with a failure in the chain system, you could have replaced a timing belt two or three times for what it is going to cost to make the chain right.
It’s scheduled unless it breaks inbetween intervals – which is an unlikely thing but is the same sort of risk. This is especially true when dealing with interference engines, as most are today. Not to mention you need to do the water pump with it. That service on an Audi or Lexus costs $1200 at an independent, and over $2000 at the dealer. And that’s every 60k miles.
I’ll take my chances on a chain engine, and check forums beforehand to see what sorts of problems can arise. I’ve heard of chain tensioner problems on certain 3.5 VQ engines (older) and also on Mercedes units (again, older).
But if it’s 3x the cost of the belt switch – we’re at $6000, and you then can just have a new engine.
Good point on the risk of the belt breaking between intervals. A coworker at a previous job had that happen on an Audi TT. It was a while back, but it might have even happened after he replaced the belt.
60k miles is a pretty short interval; I thought it was more like 110k. Maybe that’s only for 2.0L I4s.
The 3x cost of belt switch was admittedly for dramatic effect. I figured around $1k for a belt switch on most cars, with an Audi S4 (chain system on back of the engine) representing the $3k+ chain repair.
It’s mostly v8s where I hear of chain problems – BMW E38 and E39 V8s, Audi B6 and B7 S4 , Ford 4.6s, even the 5.7 hemi on automatic transmission Challengers.
I just feel the risk of “getting a bad belt” or some other small thing messing it up is higher than a failure of a chain or chain-related components.
Edit: Or the owner has -never- done the belt, and they’re at 98K miles just by pure luck.
However, 60K for sure is the recommended interval on those two engines which makes it quite a big expense. Buying them used, you’ll find they’re often for sale around the interval time, by an owner who would rather sell an 8 year old car than put $2k into a belt. The service is hard to do yourself, especially on the Audis. I’m guessing the 4.2 was in the B7 S4?
Yeah, the Audi 4.2 was in the B7 and I think B6.
CoreyDL
My experience with 2 A4 1.8Ts and 1 A6 2.7T has been pretty good. Cost to replace timing belt, water pump, tensioner and pulleys has been around $800. I have 430000 miles in total on them. Recommended interval A4s 70k miles, my interval 65k miles. A6 at 105K miles, looked new when it came out. Don’t have to do the water pumps, but with half the cost in labor, why not toss the pump, etc in?
I only see 2 turbos
Fitment and heat management will be pretty interesting. They should consult Turn One for engine note synthesizers… Forza game engine sounds are pretty good and theres no chance in hell this thing will do anything but wheeze and whistle.
I believe we’re seeing the two exhaust driven turbos in the front, and the electric turbo is somewhere out of view to the left feeding the black hoses. If you click though the Automotive News link, there’s a better picture.
The electric compressor is not a turbo……
A compressor drivrn by a turbine (you get the wording where turbo comes from?) I referred to as turbo. Thi here is a compressor driven by electric motor.
I would be deathly scared to own a car with that engine out of warranty.
On a certain level, I agree. I wonder, though, if many of us have a generational bias. To this day, my boomer dad won’t buy any turbocharged car based on his cousin’s experiences with an early Saab 99 Turbo. “Exotic” boost configurations are only going to become more and more common.
Three turbos combined with electric motors in a European car…that does not sound like a formula for low ownership costs, especially out of warranty. I think the depreciation curve on these would be very, very steep. Replacing the turbo system might cost more than a 6-8 year old car is worth, and turbos don’t last forever.
European turbos do seem to last, provided you maintain the car. In my experience, “turbo troubles” only happen to owners who tell you that “synthetic oil is a scam.”
Funny thing is, they’ll swear to never buy a turbo again (as if that was the root problem), then they’ll ruin their next non-turbo car just as fast, then they’ll come-up with a different excuse (never buy a Honda?), then they’ll ruin the next car after that.
I wouldn’t count on a used turbo lasting regardless of how you treat it if the previous owners didn’t treat it right. I wouldn’t trust such a car without full docs (carfax does wonders) and a reasonably good reason to believe that the car was often driven off boost.
Really? Why not just turbo-supercharge? No lag, instant boost, less heat, etc. Hey, and while we’re at it, let’s turbo-compound the engine for the highway, and sleeve valves so we can run it really, really hot.
This uses an electrical turbo assist like F1 cars these days to get zero lag & low(er) heat.
Moar boost makes everything better.
video from volvo on engine
All with parts made in China…nice, very nice….That’s exactly what Volvo needs. Extremely complicated engines using chinese made parts and metallurgy but assembled in Sweden (for now). That’s the recipe for future success in North America.
…..And targeting such notoriously high risk tolerance individuals as Volvo shoppers, to boot……
2025 Craigslist Ad:
4Sale 2018 Volvo S60 TTT4 (that’s the good triple-turbo one). Silver on black, 89K miles, has turbo problem. BLIS, pw, pl, pm, heated seats work great. Needs tires 2. EZ Fix. $9400 OBO.
I would amend that from “EZ fix.” To “Mechanic friend says ez fix, only needs $10 part.”
This article confirms the rumor that Volvo hired a bunch of ex-Saab engineers.
Let’s hope they got some chassis engineers as well. The recent (Ford-era) Volvos I’ve driven all had appallingly bad ride and handling. No feel, no feedback, and a stomach-raising front-back float (as opposed to up-down).
“Channeling its inner Viking death metal chef spirit”
So many places to go with this. Is there something we don’t know about the Swedish Chef? Is “Bork, bork, bork!” actually a battle song (he sings while wielding his cleaver)?
The last time I was in Norway, the taxi from the airport was driven by a little southeast Asian woman who was playing a Viking war metal CD. Breaking down stereotypes while simultaneously reinforcing them–well played.
Maybe this engine will be featured in a Swedish remake of the movie, “The Wraith.”