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

www2.mazda.com

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

#51

Post by busterarm »

mchannon wrote: post #31
IgorPartola wrote: post #5

Earlier quoted context omitted.

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.

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…

> 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.

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

#52

Post by maxxxxx »

stirkac wrote: post #2

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

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.

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

#53

Post by busterarm »

quake wrote: post #16
IgorPartola wrote: post #5

Earlier quoted context omitted.

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.

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 t…

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.

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

#54

Post by busterarm »

ynniv wrote: post #25
quake wrote: post #16

Earlier quoted context omitted.

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 t…

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.

09-11 RX-8s are rock solid dependable.

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

#55

Post by komali2 »

mtgx wrote: post #33
bsdetector wrote: post #30

Earlier quoted context omitted.

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.

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.

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."

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

#56

Post by komali2 »

busterarm wrote: post #48
_ea1k wrote: post #47

Earlier quoted context omitted.

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.

Excluding the Miata, when are sports cars ever practical?

Anytime it is time to Go Fast.

So always.

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

#57

Post by Animats »

maxxxxx wrote: post #52
stirkac wrote: post #2

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

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.

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.

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

#58

Post by TomMarius »

robin_reala wrote: post #49
oatmealsnap wrote: post #35

Earlier quoted context omitted.

Gasoline engines aren't going away for a while; even when every self-driving car is electric, there will be a market for people who want gasoline engines. If it gives a bump in fuel economy to the next (last?) generation of gasoline and hybrid vehicles, great! I also wonder if the maintainability of these engines will be the same as with diesel. That would be another big benefit.

Outside of Europe maybe. Inside, well, UK and France have already said no more ICE vehicles to be sold past 2040, and other countries are planning the similar (including India). That’s a big loss of market and consequent economy of scale.

Politicians have said things, but no laws have been passed yet - and these laws can be (and have been in the past) changed.

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

#60

Post by TomMarius »

komali2 wrote: post #56
busterarm wrote: post #48

Earlier quoted context omitted.

Excluding the Miata, when are sports cars ever practical?

Anytime it is time to Go Fast. So always.

It's always nice to be home in Prague from Munich in 2.5 instead of 4.5 hours in exchange for just 1.5l/100km more consumption (and going 250 (155 miles per hour) instead of 130 km/h).
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