Who needs diesel? SkyActiv-X HCCI sounds awesome

[Laconian]

http://www2.mazda.com/en/publicity/release/2017/201708/170808a.html

[shp4man]

http://www2.mazda.com/en/publicity/release/2017/201708/170808a.html

Nice. Hope they're successful.

[12,000 RPM]

Big stuff. I hear the supercharger will be powered electrically too. Just in time too, because Skyactiv-G engines are no good in their mainstreamers. Too effing slow, same gas mileage as VW's punchier TSI lumps.

[RomanChariot]

Spark Controlled Compression Ignition overcomes two issues that had impeded commercialization of compression ignition gasoline engines: maximizing the zone in which compression ignition is possible and achieving a seamless transition between compression ignition and spark ignition.

So a compression ignition engine with a spark plug? I don't really care if it gives the gains they are claiming.

[Laconian]

Big stuff. I hear the supercharger will be powered electrically too. Just in time too, because Skyactiv-G engines are no good in their mainstreamers. Too effing slow, same gas mileage as VW's punchier TSI lumps.

That's kind of surprising. IIRC supercharging has pretty high parasitic losses (on the order of tens of HPs?). An electric supercharger would presumably necessitate a beefier/higher voltage electrical system to handle the beefier charging, storage, and output loads.

I'm betting they use a regular supercharger, with automatic clutches for disengaging the unit when not desired.

[MrH]

Yesssss. I've been crossing my fingers for this for ages.

If this is dropping into the current mazda3, I hope it comes to a face lifted Miata.

[93JC]

Just in time too, because Skyactiv-G engines are no good in their mainstreamers. Too effing slow, same gas mileage as VW's punchier TSI lumps.

wat

Mazda 3 2.0 L = 155 hp, 7.9 s 0-60, 28/37 city/hwy
VW Golf TSI = 170 hp, 7.3 s, 25/35
Mazda 3 2.5 L = 185 hp, 6.8 s, 27/36

(0-60 times from C&D, EPA mileage ratings)

[Laconian]

I don't know where you get some of this shit from, Sporty. The current SkyActiv engines are very nice. Just not as nice as the Honda turbo 4s.

[Soup DeVille]

That's kind of surprising. IIRC supercharging has pretty high parasitic losses (on the order of tens of HPs?). An electric supercharger would presumably necessitate a beefier/higher voltage electrical system to handle the beefier charging, storage, and output loads.

I'm betting they use a regular supercharger, with automatic clutches for disengaging the unit when not desired.

An electric supercharger could also be nearly infinitely variable. It would however, unless there was a relatively large bypass plenum, need to be moving at all speeds and could never actually shut off, otherwise it would starve the engine.

Electric super chargers have been used before, but usually as short term power boosters.

[cawimmer430]

Isn't it also the characteristics of the fuel that play an important role in how and when it combusts?

[r0tor]

An electric supercharger could also be nearly infinitely variable. It would however, unless there was a relatively large bypass plenum, need to be moving at all speeds and could never actually shut off, otherwise it would starve the engine.

Electric super chargers have been used before, but usually as short term power boosters.

Unless it's an electric centrifugal supercharger


Anyways, mazda is dead to me until they can manage to build something with a 0-60 time at least in the low 5 sec range

[Soup DeVille]

Unless it's an electric centrifugal supercharger


Anyways, mazda is dead to me until they can manage to build something with a 0-60 time at least in the low 5 sec range

It would still have to rotate, wouldn't it?

[giant_mtb]

Isn't it also the characteristics of the fuel that play an important role in how and when it combusts?

Yeah, and now that gasoline and diesel are so highly standardized and widely available, they have to design the engine around the fuel instead of the other way around.

[12,000 RPM]

wat

Mazda 3 2.0 L = 155 hp, 7.9 s 0-60, 28/37 city/hwy
VW Golf TSI = 170 hp, 7.3 s, 25/35
Mazda 3 2.5 L = 185 hp, 6.8 s, 27/36

(0-60 times from C&D, EPA mileage ratings)

I don't know where you get some of this shit from, Sporty. The current SkyActiv engines are very nice. Just not as nice as the Honda turbo 4s.

All I know is the 3 2.0L I rented felt like it was down 100HP vs the Golf TSI. I'm sure with 700lb less curb weight that 2.0L would feel great.... but in the 3 it was a dog. I'm still reeling from disappointment with how that thing drove.

[r0tor]

It would still have to rotate, wouldn't it?

Centrifugal pumps are not positive displacement... They will allow flow through the pump even if it's not moving

[MX793]

All I know is the 3 2.0L I rented felt like it was down 100HP vs the Golf TSI. I'm sure with 700lb less curb weight that 2.0L would feel great.... but in the 3 it was a dog. I'm still reeling from disappointment with how that thing drove.

Different type of power delivery.  The TSI makes all of its power in the low to midrange.  At 4000 RPM, it's making 25% more power than the Mazda. 

And that's not accounting for differences in how the throttle pedals are calibrated.  It's easy to make a car "feel" quicker simply by calibrating the pedal more aggressively (e.g., open the throttle by 40 or 50% when the pedal is only depressed 1/4 of its stroke).

[MX793]

Centrifugal pumps are not positive displacement... They will allow flow through the pump even if it's not moving

True, but it will still result in a restriction in the intake path.  While it won't necessarily starve the engine, it would be like running with a clogged air filter.

[Soup DeVille]

Centrifugal pumps are not positive displacement... They will allow flow through the pump even if it's not moving

I know that, but there has to be a pretty big restriction involved.

[GoCougs]

That's kind of surprising. IIRC supercharging has pretty high parasitic losses (on the order of tens of HPs?). An electric supercharger would presumably necessitate a beefier/higher voltage electrical system to handle the beefier charging, storage, and output loads.

I'm betting they use a regular supercharger, with automatic clutches for disengaging the unit when not desired.

Well, those parasitic losses are there whether belt or electric motor driven . But as we're seeing in the real world, turbos have no mpg advantage over S/C (but turbos are cheaper to make).

Could be there is a hybrid system that powers the S/C drive motor for intermittent use (I mean, how often would a econobox need continuous max power?).

[Laconian]

Right, my point is that it will take many watts to drive an electric S/C, more than a regular 12v lead acid can provide.

[12,000 RPM]

Right, my point is that it will take many watts to drive an electric S/C, more than a regular 12v lead acid can provide.

I think they are jumping on the 48V mild hybrid wave.

Well, those parasitic losses are there whether belt or electric motor driven

Are they losses if the power comes from regenerative braking?

Different type of power delivery.  The TSI makes all of its power in the low to midrange.  At 4000 RPM, it's making 25% more power than the Mazda. 

I mean, that's where you spend your time on the street. The TSI was faster short shifting at ~4K than the Mazda 2.0 was to redline... which makes sense as the TSI is rated for like 15% more power (but really makes like 30% more). But they got the same exact gas mileage over the same commutes within weeks of each other.

[MrH]

Right, my point is that it will take many watts to drive an electric S/C, more than a regular 12v lead acid can provide.

Mazda has been using that i-Loop capacitor system to improve fuel economy for awhile....  That's what immediately comes to mind when I hear electric supercharger.

[cawimmer430]

Yeah, and now that gasoline and diesel are so highly standardized and widely available, they have to design the engine around the fuel instead of the other way around.

And this means this engine can only be sold in certain shall we say "developed" markets where the fuel quality can be guaranteed.

[Laconian]

And this means this engine can only be sold in certain shall we say "developed" markets where the fuel quality can be guaranteed.

True, diesel engines are really good at burning low quality fuel oil.

[giant_mtb]

And this means this engine can only be sold in certain shall we say "developed" markets where the fuel quality can be guaranteed.

...just like every other gasoline car sold today...?

[cawimmer430]

...just like every other gasoline car sold today...?

I believe some makes sell newer cars with older low-tech engines in some markets, like in most of Africa for example because of their poor or fluctuating fuel quality (and general lack of care about emissions).

[giant_mtb]

I believe some makes sell newer cars with older low-tech engines in some markets, like in most of Africa for example because of their poor or fluctuating fuel quality (and general lack of care about emissions).

I doubt Mazda gives a shit about that market.

[cawimmer430]

I doubt Mazda gives a shit about that market.

They should. They can sell all the Wankel engines they want over there and nobody will piss on them about something so trivial like emissions!

[12,000 RPM]

I believe some makes sell newer cars with older low-tech engines in some markets, like in most of Africa for example because of their poor or fluctuating fuel quality (and general lack of care about emissions).

They sell new Benzes in Ghana

http://mercedes-benz.com.gh/

Mazda is not a huge volume player anyway and developing markets have zero profit. So even without those issues they are probably sticking to the developing world.

Plus the way this thing works should be able to run on shit gas. It's basically controlled knock

[Laconian]

Our hypothetical implementation would definitely be much pricier than what people from developing countries can afford.