Mazda may have found the apex in ICE design with the Skyactiv-Z

https://newatlas.com/automotive/mazda-skyactiv-z/

Comments

bob1029Mar 26, 2026, 1:20 PM
> No turbocharger is used, but a small Roots-type supercharger expands the compression ignition window by adding more air to the engine to allow leaner fuel mixes – especially at higher speeds where avoiding knock is more problematic.

This is a surprising engineering decision considering the efficiency goals. I'd be curious to see how they managed to offset the parasitic losses. In a hellcat engine, the supercharger consumes anywhere from 10 to 100hp depending on engine load. You can never turn it off.

shmeeedMar 26, 2026, 2:32 PM
The Hellcat uses a massive twin-screw compressor. A Roots type supercharger is a blower, that is, a positive displacement pump with no internal compression that can run pretty efficient. Mazda's unit is comparatively small and clutched, so they can turn it off when not needed.
fxtentacleMar 26, 2026, 2:12 PM
“the apex of internal combustion engines means they’re doing more than just propelling a vehicle around roads and highways. They’d also be air purifiers, removing CO2 as they go.”

which sounds amazing, but is followed by 0 facts or information on how that might work.

advisedwangMar 26, 2026, 4:58 PM
They are putting Carbon Capture into some concept cars and a race car [1]. Some more info in the system at [2]. I don't see any benefit for this technology being in a car vs at a stationary large scale facility.

[1] https://www.hagerty.com/media/news/future-mazdas-to-capture-...

[2] https://www.carboncapturejournal.com/news/mazda-unveils-mobi...

shmeeedMar 26, 2026, 2:43 PM
This is annoying marketing bs that the motor press has been touting for decades with every new generation of efficient engines. An ICE (that's not running on H2) always generates CO2.

If it did the reverse, it would be a Fischer-Tropsch reactor. /s

linksnapzzMar 26, 2026, 4:42 PM
At operating temperatures, a modern ICE w/ a 3-way catalytic converter driving at highway speeds through the right environment (L.A. on a bad smog day) could easily have NOx and VOC levels at the tailpipe that are lower than what's going into the intake manifold.
7v3x3n3sem9vvMar 26, 2026, 4:55 PM
this is literally how Ford marketed their PZEV (practically zero emissions vehicle) cars around 2003. https://www.latimes.com/archives/la-xpm-2004-jun-09-hy-neil9...
shmeeedMar 26, 2026, 6:32 PM
That's true, and has been for quite some time. Still: NOx and VOC, but not CO2.
testing22321Mar 26, 2026, 2:58 PM
I believe there are quite a few Volvos that, when used in dense urban environments, emit cleaner air from the exhaust than they ingest.

https://www.volvocarsmississauga.com/en/news/view/how-does-t...

shmeeedMar 26, 2026, 3:52 PM
I'm sure they love people believing that, but it's a cabin air purification system, and it's about PM 2.5 particles, not CO2.

There was a dutch EV prototype a few years ago that did include an active CO2 capture system as a proof of concept.