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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

#141

Post by kw71 »

paulirwin wrote: post #126
mohaine wrote: post #89

Earlier quoted context omitted.

I'm pretty sure "wear on the spark side" is an all but solved problem at this point. Most car engines made in the last 15 years have 100k mile lifetime on the entire spark system.

I know for more recent vehicles that is probably true, but as an owner of a 2006 F-150 with the 5.4L 3V Triton V8 that had the infamous spark plug issue, I had to lol with a tinge of sadness at your "last 15 years" comment. Backstory: Ford came out the gate with a new spark plug design for the 2004 F-150 3V Triton 5.4L V8 engine (after their previous spark plug design failure in the 2V Triton where the plugs would sh…

Well, that's sure unfortunate. I care for my father in law's focus, and the iridium plugs really were good for 100k miles. In 35 years of caring for cars I have never been so frightened by the sounds and feel of unscrewing a spark plug though.

This is the one with a "permanent air filter" so they were thinking about eliminating maintenance. Boy this is going to suck when it is clogged.

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

#142

Post by maxerickson »

teraflop wrote: post #120
fnj wrote: post #102

Earlier quoted context omitted.

> So this is ... diesel without the NOx NOx is not peculiar to diesel engines. Gasoline engines also generate NOx. All internal engines make NOx. As long as you burn fuel + atmospheric air you get NOx. The atmosphere is 78% nitrogen. Some of it gets oxidized.

This makes me wonder whether it would be theoretically possible to use some of the engine's power output to extract nitrogen from the incoming air. You'd effectively be trading more CO2 pollution (because of the reduced efficiency) for less NOx pollution. My back-of-the-envelope calculations suggest that off-the-shelf oxygen concentrators aren't efficient enough to make this practical, but I don't know whether there…

A typical NOx reduction is to feed some exhaust gas into the air intake to reduce the amount of oxygen in the chamber.

https://en.wikipedia.org/wiki/Exhaust_gas_recirculation

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

#143

Post by linksnapzz »

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.

In the 1990s, the CA state gov. wanted 10% of the cars on the road to be EVs by 2000.

Wow, was that ever effective.

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

#144

Post by oh_sigh »

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…

I don't necessarily see this as a don't pass. There are some questions to the jerkiness of the power supplied, so perhaps this kind of engine would couple nicely in a hybrid design - it can charge the batteries 30% more efficiently than the closest hybrid, and the user isn't getting power to the drivetrain directly from the engine, eliminating any jerkiness.

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

#145

Post by Govindae »

fnj wrote: post #102
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…

> So this is ... diesel without the NOx NOx is not peculiar to diesel engines. Gasoline engines also generate NOx. All internal engines make NOx. As long as you burn fuel + atmospheric air you get NOx. The atmosphere is 78% nitrogen. Some of it gets oxidized.

Yes, but stratified charge combustion produces significantly more NOx in cylinder because of the excess oxygen.

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

#146

Post by oh_sigh »

ouid wrote: post #140
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.

I visited a Tesla store once in mountain view, and they have a great little demo where you can check the cost of charging your car in various states. Washington DC, for whatever reason, gets its electricity from a gasoline power plant. In Washington, the Model S gets 28 MPG. This happened a while ago so I could be misremembering, but regardless I don't believe that the environmental value of electric vehicles has bee…

That is wrong. Almost all of the energy DC uses comes from its interconnect to the RFC grid. Locally, it does look like 2/3rd of the power DC generates is nat gas, and 1/3rd gas or gas-like, but it doesn't make sense in a grid structure to assume that the energy produced near you is the energy you use.

https://www.eia.gov/state/?sid=DC#tabs-1

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

#147

Post by linksnapzz »

rsync wrote: post #123

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.

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.

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

#148

Post by pkulak »

ouid wrote: post #140
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.

I visited a Tesla store once in mountain view, and they have a great little demo where you can check the cost of charging your car in various states. Washington DC, for whatever reason, gets its electricity from a gasoline power plant. In Washington, the Model S gets 28 MPG. This happened a while ago so I could be misremembering, but regardless I don't believe that the environmental value of electric vehicles has bee…

https://en.wikipedia.org/wiki/The_long_tailpipe#Criticism

The biggest nail in the coffin of the long tailpipe fallacy is that you can drive an EV farther on the power needed to refine a gallon of gas than you can drive a ICE car on that same gallon. So, even if you built a gasoline engine that had absolutely no emissions, and oil bubbled up into crude lakes right next to every refinery, EVs would still be more efficient.

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

#149

Post by YSFEJ4SWJUVU6 »

cromulent wrote: post #131
fnj wrote: post #110

Earlier quoted context omitted.

- over 40% thermal efficiency - significant reduction in CO2 CO2 production is directly inverse-linearly related to thermal eficiency. It is silly to list both.

Would you mind explaining why (to a layman)? The Wikipedia page on thermal efficiency makes no mention of the CO2 relationship.

Thermal efficiency basically refers to just the efficiency of an ICE (or any heat engine for that matter) – i.e. how much of the chemical energy of the fuel you manage to convert into mechanical energy in the drive train. The better the efficiency, the less fuel you need to produce the same power output, obviously producing less CO2 in the process.

(To be more specific, the terms are often used interchangeably. Thermal efficiency has an exact definition in an ideal heat engine and even ways of calculating the theoretical maximum for given conditions – but CO2 or chemical reactions have nothing to do with an ideal heat engine to start with. I'd personally perhaps prefer to talk about just the efficiency in an actual ICE – even if just to be clear none of the losses are conveniently left outside the calculation.)

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

#150

Post by pkulak »

ClassyJacket wrote: post #82
komali2 wrote: post #55

Earlier quoted context omitted.

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."

I believe that's also how diesel trains work.

And submarines.
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