7 ms·

SKYACTIV-X: first commercial gasoline engine to use compression ignition

174 points by interconnector 9y ago

stirkac 9y ago
Mazda is one of those companies just don't stop revolutionizing. First they got rotary to be actually usable. Now this.
- IgorPartola 9y ago
  Did they get the rotary to be usable? I thought even at its best, it was finicky and temperamental. I have never owned or driven one, just doing some idle reading online, so asking this as a serious question.
  - quake 9y ago
    More or less usable. They did have a tendency to blow apex seals after 80k miles, which was could end up as a full rebuild of the engine. As far as how finicky a rotary can be, the biggest thing to do is let them warm up before driving, and let them cool right down after you're done. They were never an engine to replace the standard fourbanger, but they weren't any more finicky than say a BMW or Audi at the time of the RX-8
    - IgorPartola 9y ago
      Heh. I mean an engine rebuild at 80k seems kind of crazy. I am both continually amazed at the ICE and at the same time can't wait for it to die out. It's such an archaic technology. Hell, a turbine engine would be so much more fun to have in a car!
      - ynniv 9y ago
        ... as long as it isn't directly connected to the wheels? The rotational inertia would make for a very uncomfortable drive.
        linksnapzz 9y ago
        Chrysler made several generations of turbine cars in the '60s. http://www.allpar.com/mopar/turbine.html http://www.allpar.com/mopar/turbine.html It was not, in the end, a production car, but there was a lot of data gathered as to performance and reliability in real-world settings. Not too long ago, Jaguar had a concept CX-75, which was a hybrid mid-engined supercar where the piston engine was replaced with two Bladon Jets micro gas turbines. After 2008, they didn't want to commit to an expensive limited production vehicle, too bad. https://www.theengineer.co.uk/issues/18-october-2010/jet-power-bladons-microjets-enable-jaguar-turbine-hybrid/ https://www.theengineer.co.uk/issues/18-october-2010/jet-pow...
        IgorPartola 9y ago
        Damn. That sounds like they almost made it work. I wonder how those cars would have done with corn ethanol. Electric boost for initial acceleration and better heat exchangers would have probably completely eliminated the remaining problems with them. Thanks for the link!
        linksnapzz 9y ago
        Dunno about corn ethanol, but agave worked: http://www.roadandtrack.com/car-culture/a33239/that-time-the-president-of-mexico-rode-in-a-turbine-chrysler-fueled-by-tequila/ http://www.roadandtrack.com/car-culture/a33239/that-time-the...
        kalleboo 9y ago
        If anyone wants to see a turbine car in action, Jay Leno owns one and has a YouTube video on it https://www.youtube.com/watch?v=b2A5ijU3Ivs https://www.youtube.com/watch?v=b2A5ijU3Ivs
      - quake 9y ago
        Turbos are definitely taking hold in the American auto industry as well, with stuff like the Chevy Sonic and Fiesta/Focus really making good use of them with tiny engines. The 2015 Focus had an option for a 1L, 3 cylinder engine with a turbo for commuters. Great stuff.
    - ynniv 9y ago
      weren't any more finicky than say a BMW or Audi at the time of the RX-8 YMMV, but my E46 BMW has been very reliable compared to an RX-8 bought at the same time. Audi was still in the process of applying the lessons of the RS4 to their everyday cars, but I still wouldn't call the RX-8 reliable compared to its peers. As you hinted, there are a couple of problems that lead to full rebuilds before 150k miles.
      - busterarm 9y ago
        09-11 RX-8s are rock solid dependable.
      - _archon_ 9y ago
        Mazda shot themselves in the foot reliability-wise with the first generation RX-8 because they: * Underspec'd the ignition coils * Didn't do enough on-road reliability testing * Lowered the oil pressure and removed OMP ports * Designed the oil filler breather in a way that allowed oil into the intake In '04, the first wave of RX8s were coming in to the dealerships after 30k with severe misfire from the coils going bad. Mazda didn't have this failure mode in their factory service manual, so the cars got replacement engines (poorly reman'd in Mexico, not made on the Mazda Japan line). These didn't last because of poor manufacturing. Once the coil issue was figured out, the 8 became much more predictable and reliable. As noted by Busterarm, they fully got their act together with the series 2 update. [I own an '04 RX8 with ~130k miles)
    - busterarm 9y ago
      My FC has 112k miles on the engine without a rebuild. Still has good compression, but on the low side of good. Pull and rebuild is pretty easy though.
      - _archon_ 9y ago
        My 8 made it to 127k before compression mandated a rebuild, and one of the previous owners is a documented idiot. Been solid ever since.
  - mchannon 9y ago
    Owned one. Enjoyed the heck out of it. Lots of torque, lots of pep, though from what I heard, the US version (mine) had substantial increases in pollution controls which hobbled the car. Always first off the line when I wanted to be. Yes, it burned oil by design. I'd add a half-quart of non synthetic 5W-20 maybe every 1000 miles. The rear bumper required additional car washes, as it'd get a black film, no doubt from cold starts. That wasn't much of a problem. The big issue it had was flooding the engine. To trigger the condition, turn on engine, let it run for less than 1 minute, and turn it off (like pulling it in or out of a garage). Unless you floored it in neutral before shutting it off, the car would end up near-bricked. The fix was to have it towed to the dealer where they'd clean out the engine for a few hundred dollars. Later I learned you could tow-start it if you could get it up past 20mph. It'd put all kinds of foul smoke out the back when you did that but in terms of hassle, it was much better. The car had a POS OEM fuel pump under the rear seat. On hot days you'd get a vapor lock. Not the rotary's fault. Took years to find that problem, and didn't get very long with the fixed version before the stork came and the rotary had to leave.
    - toast0 9y ago
      > before the stork came and the rotary had to leave One of my friends had an rx-8, the backseats were useless for adults, but glorious for car seats.
      - _archon_ 9y ago
        I have an 8 (and am involved in sports car things as a hobby) and I find the back seats to be superior to almost all sports cars and most mid-sized normal cars for seating adults.
    - busterarm 9y ago
      > The fix was to have it towed to the dealer where they'd clean out the engine for a few hundred dollars. Later I learned you could tow-start it if you could get it up past 20mph. It'd put all kinds of foul smoke out the back when you did that but in terms of hassle, it was much better. You don't need to do all that. You can just pull the EGI INJ & EGI COMP fuse, crank it for a few seconds, replace and start it up. Many folks put a bypass switch inside the car so they don't have to get out and do it. Works great.
- mikestew 9y ago
  The rotaries leaked oil and got terrible mileage, and good luck finding someone to work on them. Other than that, they were zippy. "Usable" they might have been if you keep a low bar, but "practical" they were not.
  - deleted 9y ago
    [deleted]
  - clone1018 9y ago
    They didn't leak oil did they? They burned oil as part of the strokes right?
  - busterarm 9y ago
    Huh? My rotary doesn't leak oil. Mileage is an issue but not significantly worse than other sports cars of that era or even today. I also could probably connect you with a good rotary mechanic (or several) in all 50 states plus Puerto Rico (hell, especially Puerto Rico) The biggest issue with the FCs isn't the engine, it's the reliability of the electric systems and heat (as a distant second). With the FDs it pretty much the twin turbos. And with early RX-8s (04-early09) it's a lack of proper engine lubrication due to a design flaw.
    - deleted 9y ago
      [deleted]
  - jsight 9y ago
    Rotary engines do not "leak oil", they burn oil a modest amount of oil by design. If you think about it, there really wasn't another way to lubricate them. Practicality was pretty low, though, as you rightly point out.
    - busterarm 9y ago
      Excluding the Miata, when are sports cars ever practical?
- maxxxxx 9y ago
  Rotary is actually a good example for "revolutions" that turned out to be inferior compared to existing solutions. We will see how the new engine will perform in the real world.
  - Animats 9y ago
    Wankel engines work fairly well, but the geometry is so constraining that they can't be improved much. Can't change the shape of the cylinder head. Can't change the valve timing dynamically. That's all fixed by the geometry. They got as good as they were going to get decades ago.
    - maxxxxx 9y ago
      Wankels are cool but they really don't have an advantage over regular engines other than vibrating less as far I know. And they have a few distinct disadvantages.
      - sliverstorm 9y ago
        Better power curves & higher RPM capability, so you can use a smaller, more underpowered engine for the same application. But that never overcame their mediocre gas mileage (lack of compression/poor combustion chamber shape), oil burning (oil-lubricated apex seals), and need for frequent rebuilds.
- flavio81 9y ago
  The rotary was never invented by Mazda, it was invented in germany and applied first by NSU. Then it was licensed to many manufacturers, among which there was Mercedes-Benz, which was the manufacturer who got solved first the apex seal problem, and in the late 70s with the C111 prototype car, the first manufacturer to create a side port wankel engine (which mazda would only show on the RX8 decades later) and a 4-rotor engine (which mazda would only show on the 787 racing car in 1991. Then MB ditched the wankel engine because of low fuel efficience, something that ultimately led to mazda doing the same... in the 2000s.
- twblalock 9y ago
  Compression ignition is more an evolution than a revolution -- it's an iterative improvement on an existing technology. Skyactiv exists in the first place because Mazda does not have the money or engineering resources to build a hybrid or electric car by themselves. I suspect that in a decade or two, Mazda's decision not to start building hybrids and electric cars when the other major brands were doing so will be regarded as a serious mistake.
  - calafrax 9y ago
    investing in high efficiency gasoline engines is a much better bet. the world will be running on gasoline for decades at least. even if europe (doubtful) or US (very doubtful) pull out of gasoline there will still be billions of potential customers around the world.
Danihan 9y ago
>Compression ignition and a supercharger fitted to improve fuel economy together deliver unprecedented engine response and increase torque 10-30 percent over the current SKYACTIV-G gasoline engine.*3 Wow. I already have a 2016 Mazda 3 that gets around 40MPG (even though it's not a hybrid) and it's already pretty peppy. Probably the best car I've owned, and I've owned several nice sports sedans. Getting 40MPG is too convenient when you make longer commutes, not to mention the thing cost ~20k at 0% APR. Blows any hybrid out of the water for total COO.
- coherentpony 9y ago
  Are those imperial gallons or US gallons?
  - Danihan 9y ago
    US gallons
  - greggyb 9y ago
    I can get 40MPG (US) highway with a 2015 Mazda3 and a somewhat aggressive driving style. City is usually low 30s. The manual transmission is also one of the nicest I've ever driven. These are great cars.
    - prodikl 9y ago
      loved my 6-speed 2015 mazda 6. highway miles were truly amazing for a full sized sedan. like others said i'm glad to see mazda continuously innovating. it's paying off
    - aidenn0 9y ago
      I only wish you could get the 2.5L in a manual with no moonroof. That would probably get me to buy a new car. I have an 07 Mazdaspeed3 that is getting long-in-the-tooth, and it gets terrible mileage (19 in town, high 20s on the freeway). The best I can say about the shifter is that you get used to it. I don't think I need quite as much pep as my current car (plus all current hatchbacks that are comparable performance are north of $30k), and the 2.5L engine in the Mazda3 is nice. I like the Mazda3 better than the Focus, but if I had to get a car today it would probably be the Focus ST.
rbanffy 9y ago
How much more R&D can the internal combustion engine pay for?
- _archon_ 9y ago
  How fancy are modern cars compared to the original cars?
IgorPartola 9y ago
So how exactly does this work? And why is it more effective and how does it allow you to run super lean while producing the same amount of power? Also, presumably running lean would mean lower emissions, but is that really true?
- philipkglass 9y ago
  Running lean, highly compressed, and highly efficient reduces expected production of carbon monoxide and residual hydrocarbons. But it significantly increases nitrogen oxide formation, as in diesel engines. So I wonder how the emissions control system deals with the extra NOx -- that has (see Dieselgate and continuing related fallout) proven quite a sticky problem for high efficiency diesel engines in passenger vehicles. The cheap "solutions" were mostly cheats and the actual solutions cost more.
ajross 9y ago
Gah, terribly confusing terminology. This is a Diesel engine. "Compression ignition" is what the Diesel cycle is all about. It's just carefully tuned such that it can run on gasoline instead of kerosene (i.e. "diesel fuel"). And mostly I don't get it. This is just a convenience factor. If you want a high-efficiency diesel right now you can buy one already. Low-volatility fuels are already more energy-dense (i.e. fewer losses carrying the stuff around in the tank) and require less energy to refine. This gives you the advantage of being able to pull into a gas station without diesel available, but otherwise doesn't seem to add much.
- dagw 9y ago
  Diesel seems to be very much on the way out, with several cities discussing diesel bans. If I was to buy a new car today I certainly wouldn't consider a diesel (as opposed to two or three years ago when diesel was the future)
- vvanders 9y ago
  Yes, however common diesel fuels tend to be higher in NOx and particulates. My understanding is that because gasoline is refined to a higher degree it burns a fair bit cleaner in similar environments(and also makes it a PITA to store for more than a few months). [edit] We've got a pair of tractors around the house here, '81 diesel(pre-emissions), and '47 gasser. I can tell you which one I prefer to run from an exhaust perspective, the diesel may have torque and is a dead-simple engine but you don't want to be downwind of it when cutting heavy brush.
  - toast0 9y ago
    NOx emissions from a diesel engine are from atmospheric nitrogen and oxygen, not from the fuel. I welcome further clarifications, but my understanding is that this engine will not produce NOx like a standard diesel because the fuel/air mix will be tightly controlled like in a gasoline engine, and temperature and pressure will be significantly less than a standard diesel. Additionally, it seems the timing of the fuel injection will be much earlier than a diesel, resulting in more complete air/fuel mixture; this is possible because gasoline has a higher ignition temperature, so fuel can be injected early and ignition won't happen until the compression stroke; diesel fuel would ignite during injection regardless of where in the cycle.
ChuckMcM 9y ago
A reuters story on how it works: https://www.reuters.com/article/us-mazda-strategy-idUSKBN1AO0E7 https://www.reuters.com/article/us-mazda-strategy-idUSKBN1AO... So this is 'gasoline' diesel. Or diesel without the NOx. Which, in theory, would give better fuel economy and possibly better torque. And it will ship in cars in the 2019 model year (so possibly as early as late next year). To me, it sounds like a "Don't pass"[1] bet on electric cars. Which they also are working with Toyota on electric cars so perhaps it is a fall back plan. It will be interesting to see how it fares. There are a lot of products that are built as the other side of an industry change bet. Sun created a workstation on the 68040 in case the SPARCStation didn't meet expectations as an example. [1] In the dice game Craps, the "Don't Pass" bet is against the current player 'winning.'
- bsdetector 9y ago
  Or a bet on hybrids. Hybrids enable new types of engines that for instance operate at constant rate or that are under-powered for acceleration from a stop or going uphill.
  - mtgx 9y ago
    I don't think hybrids have any future except in the heaviest of vehicles, where batteries won't make sense for another few decades. We're already seeing companies being interested in making battery-only buses, tractors, semis, and even airplanes. Not all models of those types of vehicles may work with batteries, but it's a sign of what the future could bring.
    - komali2 9y ago
      Total individual perspective here, but my dad took me on his worksite like 15 years ago to see the big super gorram awesome trucks (seriously those things are HUGE). When I asked about the engines, he said the trucks had massive diesel generators that powered motors, that in turn powered the wheels and hydraulics. So in a way, lots of construction equipment has kind of already been "hybrid."
maerF0x0 9y ago
I think this is a great step forward for ICE . Combining this technology into generators (and cars like chevy volt) will make an extremely convenient and fuel efficient vehicle.
elihu 9y ago
Maybe this is old news to people who pay attention to car news, but the most interesting thing to me is this line from the press release: > From 2019, start introducing electric vehicles and other electric drive technologies in regions that use a high ratio of clean energy for power generation or restrict certain vehicles to reduce air pollution I've been kind of disappointed that Mazda hasn't gotten into the electric car market yet; I'm glad to see they're coming around.
- seanmcdirmid 9y ago
  Mazda is kind of small, it would be like expecting an electric vehicle from Subaru. Ya, it will happen eventually, but the big guys are going to have the resources to go first (well, and startups built on the concept itself). Also, hydrogen was supposed to be the big clean fuel in Japan, but that fell by the wayside when the bigger Chinese market decided it would be electric.
- 33W 9y ago
  They have an interesting somewhat-hybrid called i-eloop that uses regenerative braking and a capacitor to power auxiliary systems: http://www.mazda.com/en/innovation/technology/env/i-eloop/ http://www.mazda.com/en/innovation/technology/env/i-eloop/
- btian 9y ago
  Mazda is a small company. They don't have the kind of R&D budget to make EVs.
- skgoa 9y ago
  Keep in mind that the electric section of the overall car marjket is just 1-1.5% right now. It's just not a significant market right now. Making an electric car is only good for building know-how. In the industry, the Chevy Bolt is expected to be the first electric car to end up being profitable. Next year's Audi Q6 e-tron quattro (what a name...) is expected to be the second. They are the first specimen of a new generate of electric cars that are for-profit mass production products from the ground up. By 2025 virtually every car manufacturer will be competing seriously in the electric market. This generational change is happening because as batteries and fuel cells are getting cheaper rapidly. We are coming up on the cross-over point where an electric car can be made profitably right now. But this also means that there was no point for the likes of Mazda to even work on electric cars before now.
pedrocr 9y ago
Technologies are always at their best when they're already being obsoleted. Just as electric cars become practical ICEs are getting great and so are the transmissions, making for great modern powertrains. There were rumors last year in F1 that one of the manufacturers was doing HCCI for it's engine (the same that Mazda has done here). I don't think any actually did but Ferrari did introduce a jet ignition system[1] that allows them to run much leaner. I wonder if anyone is thinking of adapting that to normal road cars. [1] http://www.motorsportmagazine.com/opinion/f1/ferraris-formula-1-jet-ignition http://www.motorsportmagazine.com/opinion/f1/ferraris-formul...
devy 9y ago
SKYACTIV-X is the world's first commercial gasoline engine to use compression ignition, in which the fuel-air mixture ignites spontaneously when compressed by the piston. Just pure curiosity, I wonder if SKYACTIV-X engine would also also consume diesel or gasoline/diesel mixtures?
- aidenn0 9y ago
  Almost certainly not, as diesel and gasoline have very different self-ignition properties.
  - ticklemyelmo 9y ago
    I wonder whether this engine will specifically require you to fill up with NON-premium gas.
    - tcdent 9y ago
      To elaborate, higher octane fuel exists solely to prevent self-detonation in higher compression engines by slowing the fuel's burn rate.
    - aidenn0 9y ago
      I suspect that when operation in compression-detonation mode, it will inject the fuel late enough into the compression stroke that the difference between 87 and 97 octane fuel won't be that big of a deal. If it does make a difference then I would expect they would design for the higher octane rating gas to prevent user-error.
    - _archon_ 9y ago
      I anticipate the engine's control computer will be able to adapt in any case. It's like the Mercedes driver who puts in 87... it'll work, and the gas is cheaper, but the tradeoff is the engine runs in "poor fuel" mode and is less efficient, eliminating any savings.
lini 9y ago
Mercedes Benz introduced something very similar to this ten years ago[1]. The engine was using HCCI at low RPM and conventional spark-plug ignition at higher RPM. [1] https://en.wikipedia.org/wiki/DiesOtto https://en.wikipedia.org/wiki/DiesOtto
- Neil44 9y ago
  That was purely experimental though - Mazda's is going on sale to the public which indicates that this is a much more evolved product. Whilst most other manufacturers have persued downsizing and turbos to get efficciency on paper (at the expense of real world emmissions) Mazda have gone another road with their SkyActiv technology and it seems to be paying off for them.
rsync 9y ago
Can we please get somebody to create: blahblah-notelectric-blahblah.blogspot.com ? Then you can just collect all of these late stage ICE optimization press releases in one place. And we can ignore them.
- linksnapzz 9y ago
  I'd like a similar repository, for all the predictions made by electric-car proponents about when all ICE units will be phased out, and by what date. Especially when predictions are made regarding the viability of this or that gascar company who is seen as being insufficiently hitched to the electric bandwagon, as though powertrain technology was the alpha-and-omega of carmaking.
userbinator 9y ago
I consider the headline slightly misleading, since compression ignition engines that run on a variety of fuels, including gasoline, were relatively popular around the turn of the century: https://en.wikipedia.org/wiki/Hot-bulb_engine#Advantages https://en.wikipedia.org/wiki/Hot-bulb_engine#Advantages Another big attraction with the hot-bulb engine was its ability to run on a wide range of fuels. Even poorly combustible fuels could be used, since a combination of vaporiser- and compression ignition meant that such fuels could be made to burn. The usual fuel was fuel oil, similar to modern-day diesel fuel, but natural gas, kerosene, crude oil, vegetable oil or creosote could also be used. Also known as "semidiesels".
grondilu 9y ago
A nice YouTube video about what this is about: https://www.youtube.com/watch?v=OVWZFdb_AGc https://www.youtube.com/watch?v=OVWZFdb_AGc

Mazda is one of those companies just don't stop revolutionizing. First they got rotary to be actually usable. Now this.

IgorPartola 9y ago
Did they get the rotary to be usable? I thought even at its best, it was finicky and temperamental. I have never owned or driven one, just doing some idle reading online, so asking this as a serious question.
- quake 9y ago
  More or less usable. They did have a tendency to blow apex seals after 80k miles, which was could end up as a full rebuild of the engine. As far as how finicky a rotary can be, the biggest thing to do is let them warm up before driving, and let them cool right down after you're done. They were never an engine to replace the standard fourbanger, but they weren't any more finicky than say a BMW or Audi at the time of the RX-8
  - IgorPartola 9y ago
    Heh. I mean an engine rebuild at 80k seems kind of crazy. I am both continually amazed at the ICE and at the same time can't wait for it to die out. It's such an archaic technology. Hell, a turbine engine would be so much more fun to have in a car!
    - ynniv 9y ago
      ... as long as it isn't directly connected to the wheels? The rotational inertia would make for a very uncomfortable drive.
      - linksnapzz 9y ago
        Chrysler made several generations of turbine cars in the '60s. http://www.allpar.com/mopar/turbine.html http://www.allpar.com/mopar/turbine.html It was not, in the end, a production car, but there was a lot of data gathered as to performance and reliability in real-world settings. Not too long ago, Jaguar had a concept CX-75, which was a hybrid mid-engined supercar where the piston engine was replaced with two Bladon Jets micro gas turbines. After 2008, they didn't want to commit to an expensive limited production vehicle, too bad. https://www.theengineer.co.uk/issues/18-october-2010/jet-power-bladons-microjets-enable-jaguar-turbine-hybrid/ https://www.theengineer.co.uk/issues/18-october-2010/jet-pow...
        IgorPartola 9y ago
        Damn. That sounds like they almost made it work. I wonder how those cars would have done with corn ethanol. Electric boost for initial acceleration and better heat exchangers would have probably completely eliminated the remaining problems with them. Thanks for the link!
        linksnapzz 9y ago
        Dunno about corn ethanol, but agave worked: http://www.roadandtrack.com/car-culture/a33239/that-time-the-president-of-mexico-rode-in-a-turbine-chrysler-fueled-by-tequila/ http://www.roadandtrack.com/car-culture/a33239/that-time-the...
        kalleboo 9y ago
        If anyone wants to see a turbine car in action, Jay Leno owns one and has a YouTube video on it https://www.youtube.com/watch?v=b2A5ijU3Ivs https://www.youtube.com/watch?v=b2A5ijU3Ivs
    - quake 9y ago
      Turbos are definitely taking hold in the American auto industry as well, with stuff like the Chevy Sonic and Fiesta/Focus really making good use of them with tiny engines. The 2015 Focus had an option for a 1L, 3 cylinder engine with a turbo for commuters. Great stuff.
  - ynniv 9y ago
    weren't any more finicky than say a BMW or Audi at the time of the RX-8 YMMV, but my E46 BMW has been very reliable compared to an RX-8 bought at the same time. Audi was still in the process of applying the lessons of the RS4 to their everyday cars, but I still wouldn't call the RX-8 reliable compared to its peers. As you hinted, there are a couple of problems that lead to full rebuilds before 150k miles.
    - busterarm 9y ago
      09-11 RX-8s are rock solid dependable.
    - _archon_ 9y ago
      Mazda shot themselves in the foot reliability-wise with the first generation RX-8 because they: * Underspec'd the ignition coils * Didn't do enough on-road reliability testing * Lowered the oil pressure and removed OMP ports * Designed the oil filler breather in a way that allowed oil into the intake In '04, the first wave of RX8s were coming in to the dealerships after 30k with severe misfire from the coils going bad. Mazda didn't have this failure mode in their factory service manual, so the cars got replacement engines (poorly reman'd in Mexico, not made on the Mazda Japan line). These didn't last because of poor manufacturing. Once the coil issue was figured out, the 8 became much more predictable and reliable. As noted by Busterarm, they fully got their act together with the series 2 update. [I own an '04 RX8 with ~130k miles)
  - busterarm 9y ago
    My FC has 112k miles on the engine without a rebuild. Still has good compression, but on the low side of good. Pull and rebuild is pretty easy though.
    - _archon_ 9y ago
      My 8 made it to 127k before compression mandated a rebuild, and one of the previous owners is a documented idiot. Been solid ever since.
- mchannon 9y ago
  Owned one. Enjoyed the heck out of it. Lots of torque, lots of pep, though from what I heard, the US version (mine) had substantial increases in pollution controls which hobbled the car. Always first off the line when I wanted to be. Yes, it burned oil by design. I'd add a half-quart of non synthetic 5W-20 maybe every 1000 miles. The rear bumper required additional car washes, as it'd get a black film, no doubt from cold starts. That wasn't much of a problem. The big issue it had was flooding the engine. To trigger the condition, turn on engine, let it run for less than 1 minute, and turn it off (like pulling it in or out of a garage). Unless you floored it in neutral before shutting it off, the car would end up near-bricked. The fix was to have it towed to the dealer where they'd clean out the engine for a few hundred dollars. Later I learned you could tow-start it if you could get it up past 20mph. It'd put all kinds of foul smoke out the back when you did that but in terms of hassle, it was much better. The car had a POS OEM fuel pump under the rear seat. On hot days you'd get a vapor lock. Not the rotary's fault. Took years to find that problem, and didn't get very long with the fixed version before the stork came and the rotary had to leave.
  - toast0 9y ago
    > before the stork came and the rotary had to leave One of my friends had an rx-8, the backseats were useless for adults, but glorious for car seats.
    - _archon_ 9y ago
      I have an 8 (and am involved in sports car things as a hobby) and I find the back seats to be superior to almost all sports cars and most mid-sized normal cars for seating adults.
  - busterarm 9y ago
    > The fix was to have it towed to the dealer where they'd clean out the engine for a few hundred dollars. Later I learned you could tow-start it if you could get it up past 20mph. It'd put all kinds of foul smoke out the back when you did that but in terms of hassle, it was much better. You don't need to do all that. You can just pull the EGI INJ & EGI COMP fuse, crank it for a few seconds, replace and start it up. Many folks put a bypass switch inside the car so they don't have to get out and do it. Works great.
mikestew 9y ago
The rotaries leaked oil and got terrible mileage, and good luck finding someone to work on them. Other than that, they were zippy. "Usable" they might have been if you keep a low bar, but "practical" they were not.
- deleted 9y ago
  [deleted]
- clone1018 9y ago
  They didn't leak oil did they? They burned oil as part of the strokes right?
- busterarm 9y ago
  Huh? My rotary doesn't leak oil. Mileage is an issue but not significantly worse than other sports cars of that era or even today. I also could probably connect you with a good rotary mechanic (or several) in all 50 states plus Puerto Rico (hell, especially Puerto Rico) The biggest issue with the FCs isn't the engine, it's the reliability of the electric systems and heat (as a distant second). With the FDs it pretty much the twin turbos. And with early RX-8s (04-early09) it's a lack of proper engine lubrication due to a design flaw.
  - deleted 9y ago
    [deleted]
- jsight 9y ago
  Rotary engines do not "leak oil", they burn oil a modest amount of oil by design. If you think about it, there really wasn't another way to lubricate them. Practicality was pretty low, though, as you rightly point out.
  - busterarm 9y ago
    Excluding the Miata, when are sports cars ever practical?
maxxxxx 9y ago
Rotary is actually a good example for "revolutions" that turned out to be inferior compared to existing solutions. We will see how the new engine will perform in the real world.
- Animats 9y ago
  Wankel engines work fairly well, but the geometry is so constraining that they can't be improved much. Can't change the shape of the cylinder head. Can't change the valve timing dynamically. That's all fixed by the geometry. They got as good as they were going to get decades ago.
  - maxxxxx 9y ago
    Wankels are cool but they really don't have an advantage over regular engines other than vibrating less as far I know. And they have a few distinct disadvantages.
    - sliverstorm 9y ago
      Better power curves & higher RPM capability, so you can use a smaller, more underpowered engine for the same application. But that never overcame their mediocre gas mileage (lack of compression/poor combustion chamber shape), oil burning (oil-lubricated apex seals), and need for frequent rebuilds.
flavio81 9y ago
The rotary was never invented by Mazda, it was invented in germany and applied first by NSU. Then it was licensed to many manufacturers, among which there was Mercedes-Benz, which was the manufacturer who got solved first the apex seal problem, and in the late 70s with the C111 prototype car, the first manufacturer to create a side port wankel engine (which mazda would only show on the RX8 decades later) and a 4-rotor engine (which mazda would only show on the 787 racing car in 1991. Then MB ditched the wankel engine because of low fuel efficience, something that ultimately led to mazda doing the same... in the 2000s.
twblalock 9y ago
Compression ignition is more an evolution than a revolution -- it's an iterative improvement on an existing technology. Skyactiv exists in the first place because Mazda does not have the money or engineering resources to build a hybrid or electric car by themselves. I suspect that in a decade or two, Mazda's decision not to start building hybrids and electric cars when the other major brands were doing so will be regarded as a serious mistake.
- calafrax 9y ago
  investing in high efficiency gasoline engines is a much better bet. the world will be running on gasoline for decades at least. even if europe (doubtful) or US (very doubtful) pull out of gasoline there will still be billions of potential customers around the world.

>Compression ignition and a supercharger fitted to improve fuel economy together deliver unprecedented engine response and increase torque 10-30 percent over the current SKYACTIV-G gasoline engine.*3 Wow. I already have a 2016 Mazda 3 that gets around 40MPG (even though it's not a hybrid) and it's already pretty peppy. Probably the best car I've owned, and I've owned several nice sports sedans. Getting 40MPG is too convenient when you make longer commutes, not to mention the thing cost ~20k at 0% APR. Blows any hybrid out of the water for total COO.

coherentpony 9y ago
Are those imperial gallons or US gallons?
- Danihan 9y ago
  US gallons
- greggyb 9y ago
  I can get 40MPG (US) highway with a 2015 Mazda3 and a somewhat aggressive driving style. City is usually low 30s. The manual transmission is also one of the nicest I've ever driven. These are great cars.
  - prodikl 9y ago
    loved my 6-speed 2015 mazda 6. highway miles were truly amazing for a full sized sedan. like others said i'm glad to see mazda continuously innovating. it's paying off
  - aidenn0 9y ago
    I only wish you could get the 2.5L in a manual with no moonroof. That would probably get me to buy a new car. I have an 07 Mazdaspeed3 that is getting long-in-the-tooth, and it gets terrible mileage (19 in town, high 20s on the freeway). The best I can say about the shifter is that you get used to it. I don't think I need quite as much pep as my current car (plus all current hatchbacks that are comparable performance are north of $30k), and the 2.5L engine in the Mazda3 is nice. I like the Mazda3 better than the Focus, but if I had to get a car today it would probably be the Focus ST.

rbanffy 9y ago

How much more R&D can the internal combustion engine pay for?

_archon_ 9y ago
How fancy are modern cars compared to the original cars?

IgorPartola 9y ago

So how exactly does this work? And why is it more effective and how does it allow you to run super lean while producing the same amount of power? Also, presumably running lean would mean lower emissions, but is that really true?

philipkglass 9y ago
Running lean, highly compressed, and highly efficient reduces expected production of carbon monoxide and residual hydrocarbons. But it significantly increases nitrogen oxide formation, as in diesel engines. So I wonder how the emissions control system deals with the extra NOx -- that has (see Dieselgate and continuing related fallout) proven quite a sticky problem for high efficiency diesel engines in passenger vehicles. The cheap "solutions" were mostly cheats and the actual solutions cost more.

ajross 9y ago

Gah, terribly confusing terminology. This is a Diesel engine. "Compression ignition" is what the Diesel cycle is all about. It's just carefully tuned such that it can run on gasoline instead of kerosene (i.e. "diesel fuel"). And mostly I don't get it. This is just a convenience factor. If you want a high-efficiency diesel right now you can buy one already. Low-volatility fuels are already more energy-dense (i.e. fewer losses carrying the stuff around in the tank) and require less energy to refine. This gives you the advantage of being able to pull into a gas station without diesel available, but otherwise doesn't seem to add much.

dagw 9y ago
Diesel seems to be very much on the way out, with several cities discussing diesel bans. If I was to buy a new car today I certainly wouldn't consider a diesel (as opposed to two or three years ago when diesel was the future)
vvanders 9y ago
Yes, however common diesel fuels tend to be higher in NOx and particulates. My understanding is that because gasoline is refined to a higher degree it burns a fair bit cleaner in similar environments(and also makes it a PITA to store for more than a few months). [edit] We've got a pair of tractors around the house here, '81 diesel(pre-emissions), and '47 gasser. I can tell you which one I prefer to run from an exhaust perspective, the diesel may have torque and is a dead-simple engine but you don't want to be downwind of it when cutting heavy brush.
- toast0 9y ago
  NOx emissions from a diesel engine are from atmospheric nitrogen and oxygen, not from the fuel. I welcome further clarifications, but my understanding is that this engine will not produce NOx like a standard diesel because the fuel/air mix will be tightly controlled like in a gasoline engine, and temperature and pressure will be significantly less than a standard diesel. Additionally, it seems the timing of the fuel injection will be much earlier than a diesel, resulting in more complete air/fuel mixture; this is possible because gasoline has a higher ignition temperature, so fuel can be injected early and ignition won't happen until the compression stroke; diesel fuel would ignite during injection regardless of where in the cycle.

ChuckMcM 9y ago

A reuters story on how it works: https://www.reuters.com/article/us-mazda-strategy-idUSKBN1AO0E7 https://www.reuters.com/article/us-mazda-strategy-idUSKBN1AO... So this is 'gasoline' diesel. Or diesel without the NOx. Which, in theory, would give better fuel economy and possibly better torque. And it will ship in cars in the 2019 model year (so possibly as early as late next year). To me, it sounds like a "Don't pass"[1] bet on electric cars. Which they also are working with Toyota on electric cars so perhaps it is a fall back plan. It will be interesting to see how it fares. There are a lot of products that are built as the other side of an industry change bet. Sun created a workstation on the 68040 in case the SPARCStation didn't meet expectations as an example. [1] In the dice game Craps, the "Don't Pass" bet is against the current player 'winning.'

bsdetector 9y ago
Or a bet on hybrids. Hybrids enable new types of engines that for instance operate at constant rate or that are under-powered for acceleration from a stop or going uphill.
- mtgx 9y ago
  I don't think hybrids have any future except in the heaviest of vehicles, where batteries won't make sense for another few decades. We're already seeing companies being interested in making battery-only buses, tractors, semis, and even airplanes. Not all models of those types of vehicles may work with batteries, but it's a sign of what the future could bring.
  - komali2 9y ago
    Total individual perspective here, but my dad took me on his worksite like 15 years ago to see the big super gorram awesome trucks (seriously those things are HUGE). When I asked about the engines, he said the trucks had massive diesel generators that powered motors, that in turn powered the wheels and hydraulics. So in a way, lots of construction equipment has kind of already been "hybrid."

maerF0x0 9y ago

I think this is a great step forward for ICE . Combining this technology into generators (and cars like chevy volt) will make an extremely convenient and fuel efficient vehicle.

elihu 9y ago

Maybe this is old news to people who pay attention to car news, but the most interesting thing to me is this line from the press release: > From 2019, start introducing electric vehicles and other electric drive technologies in regions that use a high ratio of clean energy for power generation or restrict certain vehicles to reduce air pollution I've been kind of disappointed that Mazda hasn't gotten into the electric car market yet; I'm glad to see they're coming around.

seanmcdirmid 9y ago
Mazda is kind of small, it would be like expecting an electric vehicle from Subaru. Ya, it will happen eventually, but the big guys are going to have the resources to go first (well, and startups built on the concept itself). Also, hydrogen was supposed to be the big clean fuel in Japan, but that fell by the wayside when the bigger Chinese market decided it would be electric.
33W 9y ago
They have an interesting somewhat-hybrid called i-eloop that uses regenerative braking and a capacitor to power auxiliary systems: http://www.mazda.com/en/innovation/technology/env/i-eloop/ http://www.mazda.com/en/innovation/technology/env/i-eloop/
btian 9y ago
Mazda is a small company. They don't have the kind of R&D budget to make EVs.
skgoa 9y ago
Keep in mind that the electric section of the overall car marjket is just 1-1.5% right now. It's just not a significant market right now. Making an electric car is only good for building know-how. In the industry, the Chevy Bolt is expected to be the first electric car to end up being profitable. Next year's Audi Q6 e-tron quattro (what a name...) is expected to be the second. They are the first specimen of a new generate of electric cars that are for-profit mass production products from the ground up. By 2025 virtually every car manufacturer will be competing seriously in the electric market. This generational change is happening because as batteries and fuel cells are getting cheaper rapidly. We are coming up on the cross-over point where an electric car can be made profitably right now. But this also means that there was no point for the likes of Mazda to even work on electric cars before now.

pedrocr 9y ago

Technologies are always at their best when they're already being obsoleted. Just as electric cars become practical ICEs are getting great and so are the transmissions, making for great modern powertrains. There were rumors last year in F1 that one of the manufacturers was doing HCCI for it's engine (the same that Mazda has done here). I don't think any actually did but Ferrari did introduce a jet ignition system[1] that allows them to run much leaner. I wonder if anyone is thinking of adapting that to normal road cars. [1] http://www.motorsportmagazine.com/opinion/f1/ferraris-formula-1-jet-ignition http://www.motorsportmagazine.com/opinion/f1/ferraris-formul...

devy 9y ago

SKYACTIV-X is the world's first commercial gasoline engine to use compression ignition, in which the fuel-air mixture ignites spontaneously when compressed by the piston. Just pure curiosity, I wonder if SKYACTIV-X engine would also also consume diesel or gasoline/diesel mixtures?

aidenn0 9y ago
Almost certainly not, as diesel and gasoline have very different self-ignition properties.
- ticklemyelmo 9y ago
  I wonder whether this engine will specifically require you to fill up with NON-premium gas.
  - tcdent 9y ago
    To elaborate, higher octane fuel exists solely to prevent self-detonation in higher compression engines by slowing the fuel's burn rate.
  - aidenn0 9y ago
    I suspect that when operation in compression-detonation mode, it will inject the fuel late enough into the compression stroke that the difference between 87 and 97 octane fuel won't be that big of a deal. If it does make a difference then I would expect they would design for the higher octane rating gas to prevent user-error.
  - _archon_ 9y ago
    I anticipate the engine's control computer will be able to adapt in any case. It's like the Mercedes driver who puts in 87... it'll work, and the gas is cheaper, but the tradeoff is the engine runs in "poor fuel" mode and is less efficient, eliminating any savings.

lini 9y ago

Mercedes Benz introduced something very similar to this ten years ago[1]. The engine was using HCCI at low RPM and conventional spark-plug ignition at higher RPM. [1] https://en.wikipedia.org/wiki/DiesOtto https://en.wikipedia.org/wiki/DiesOtto

Neil44 9y ago
That was purely experimental though - Mazda's is going on sale to the public which indicates that this is a much more evolved product. Whilst most other manufacturers have persued downsizing and turbos to get efficciency on paper (at the expense of real world emmissions) Mazda have gone another road with their SkyActiv technology and it seems to be paying off for them.

rsync 9y ago

Can we please get somebody to create: blahblah-notelectric-blahblah.blogspot.com ? Then you can just collect all of these late stage ICE optimization press releases in one place. And we can ignore them.

linksnapzz 9y ago
I'd like a similar repository, for all the predictions made by electric-car proponents about when all ICE units will be phased out, and by what date. Especially when predictions are made regarding the viability of this or that gascar company who is seen as being insufficiently hitched to the electric bandwagon, as though powertrain technology was the alpha-and-omega of carmaking.

userbinator 9y ago

I consider the headline slightly misleading, since compression ignition engines that run on a variety of fuels, including gasoline, were relatively popular around the turn of the century: https://en.wikipedia.org/wiki/Hot-bulb_engine#Advantages https://en.wikipedia.org/wiki/Hot-bulb_engine#Advantages Another big attraction with the hot-bulb engine was its ability to run on a wide range of fuels. Even poorly combustible fuels could be used, since a combination of vaporiser- and compression ignition meant that such fuels could be made to burn. The usual fuel was fuel oil, similar to modern-day diesel fuel, but natural gas, kerosene, crude oil, vegetable oil or creosote could also be used. Also known as "semidiesels".

grondilu 9y ago

A nice YouTube video about what this is about: https://www.youtube.com/watch?v=OVWZFdb_AGc https://www.youtube.com/watch?v=OVWZFdb_AGc