How much more R&D can the internal combustion engine pay for?
SKYACTIV-X: first commercial gasoline engine to use compression ignition
11–20 of 241 posts
Re: SKYACTIV-X: first commercial gasoline engine to use compression ignition
#12So 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?
Re: SKYACTIV-X: first commercial gasoline engine to use compression ignition
#13Gah, 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.
Re: SKYACTIV-X: first commercial gasoline engine to use compression ignition
#14Earlier quoted context omitted.
OK, so honest question: I have a 2012 Mazda 3 which, presumably, gets 40mpg. But I can't realistically get anything above 29mpg on average. Am I just an aggressive driver? :) [edit] I agree, by the way, that the cars are incredibly fun to drive, for being "fuel efficient."
2012 had half Skyactiv and half .. non-Skyactiv. The expected MPG on the non is around 30. You'd have a badge on the rear of the car (if sold in US, at least) that would indicate Skyactiv.
I have the badge.
Re: SKYACTIV-X: first commercial gasoline engine to use compression ignition
#15>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 c…
I think you are misreading that. The increase of 10-30 percent is in torque, not MPG.
Gah, you're right, thanks. Edited.
Re: SKYACTIV-X: first commercial gasoline engine to use compression ignition
#16Mazda is one of those companies just don't stop revolutionizing. First they got rotary to be actually usable. Now this.
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 the RX-8
Re: SKYACTIV-X: first commercial gasoline engine to use compression ignition
#17Earlier 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…
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!
Re: SKYACTIV-X: first commercial gasoline engine to use compression ignition
#18A reuters story on how it works: 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.'
Re: SKYACTIV-X: first commercial gasoline engine to use compression ignition
#19Mazda is one of those companies just don't stop revolutionizing. First they got rotary to be actually usable. Now this.
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.
Re: SKYACTIV-X: first commercial gasoline engine to use compression ignition
#20Gah, 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. few…
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)