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

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

#71

Post by komali2 »

TomMarius wrote: post #60
komali2 wrote: post #56

Earlier quoted context omitted.

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).

We have the big and beautiful 280 between Mountain View and San Francisco, and I thank goodness every time I make my way to the city for it. I'd never go the speeds on my bike I do on 280 anywhere else, but it's just such a gosh darn huge road I get to make a 45-60 minute trip in like 30 minutes.

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

#72

Post by rm445 »

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…

You should have held out on the wait-and-see. The moderate-sized rear cabin with those little suicide doors (you are talking about the RX-8, aren't you?) is absolutely great for baby and child seats.

Also, yeah, I had my RX-8 tow started once. The recovery guy actually suggested I drive his truck while he sat in the car and tried to start it. So there I was with the new experience of driving an enormous full-size recovery vehicle, getting quite concerned as I looked in the mirror and saw clouds of white smoke pouring out of my car's exhaust! But, once properly wary of flooding, the car didn't give me any trouble before or since.

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

#73

Post by flamedoge »

busterarm wrote: post #51
mchannon wrote: post #31

Earlier quoted context omitted.

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. M…

They could've literally put this as a workaround

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

#74

Post by TomMarius »

komali2 wrote: post #71
TomMarius wrote: post #60

Earlier quoted context omitted.

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).

We have the big and beautiful 280 between Mountain View and San Francisco, and I thank goodness every time I make my way to the city for it. I'd never go the speeds on my bike I do on 280 anywhere else, but it's just such a gosh darn huge road I get to make a 45-60 minute trip in like 30 minutes.

I though you Americans have it pretty rough when you're caught going over speed limit?

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

#75

Post by flamedoge »

ddeck wrote: post #23
IgorPartola wrote: post #10

Earlier quoted context omitted.

I think you are misreading that. The increase of 10-30 percent is in torque, not MPG.

This is correct, but they're are also predicting an equivalent improvement in fuel consumption: "Compared to the current lineup of SkyActiv-G engines, the SkyActiv-X line should use between 20 and 30 percent less fuel." http://newatlas.com/mazda-skyactiv-x-compression-ignition/50...

more torque = less rpm @ same hp?

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

#76

Post by devy » 

   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?

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

#77

Post by komali2 »

TomMarius wrote: post #74
komali2 wrote: post #71

Earlier quoted context omitted.

We have the big and beautiful 280 between Mountain View and San Francisco, and I thank goodness every time I make my way to the city for it. I'd never go the speeds on my bike I do on 280 anywhere else, but it's just such a gosh darn huge road I get to make a 45-60 minute trip in like 30 minutes.

I though you Americans have it pretty rough when you're caught going over speed limit?

That's actually a big question I have as a new Californian. In Houston, you got caught, every time, if you sped on the freeways. The cops were everywhere.

Here not only do I rarely see cops, I've read in the local papers that cops can't pull people over for speeding if EVERYONE is speeding. You have to be speeding far above average. So everyone is actually incentivized to speed together.

When I first got here I saw comically low speed limit signs - as low as 55mph on freeways! And averages of 65! That's INSANELY slow for how big these freeways are! But apparently it doesn't matter in California, here everyone just speeds and is protected as a group.

I don't doubt that I'll pay my dues eventually. You don't get away with 95mph on a sportbike forever. We make targets of ourselves. That's fine, in Houston I got ticketed ~200USD every three years or so, that's a fair price to get to go above the speed limit for me.

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

#78

Post by cmrdporcupine »

bsdetector wrote: post #30
ChuckMcM wrote: post #18

A 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 Toyo…

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 bet on plugin hybrids, specifically ones with large batteries. This seems to be an unpopular opinion, but I think the Voltec drivetrain shows what's possible here. Pure EV purists dislike PHEVs because they have the complexity of an ICE car + an EV car, but I think there's some serious advantages. Like you say, Atkinson cycle for electricity generation for when the battery drains beyond smaller commute ranges. Something like this new Mazda engine in that context would make quite a bit of sense for overall fuel efficiency.

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

#79

Post by syphilis2 »

borski wrote: post #7
Danihan wrote: post #3

>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…

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."

I have a 2012 Mazda3 sedan with the 2.0L Skyactiv-G engine. I drive a daily commute on a 50-50 highway/stop-n-go mix. My average mpg has consistently been 35 mpg (40 highway, 32 off). The hatchback has slightly worse mpg, so does the manual transmission, but 29 mpg sounds more like the non-skyactiv 2.0L engine. The 2.5L sport engine would be closer to 25 mpg.

I'd check under the hood just to make sure :) then fill up the tires, reset the average fuel economy, and baby it on the highway to see if you can get around the expected 40 mpg.

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