alt.hn

3/26/2026 at 9:38:19 AM

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

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

by breve

3/26/2026 at 2:12:27 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.

by fxtentacle

3/26/2026 at 2:43:26 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

by shmeeed

3/26/2026 at 4:42:33 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.

by linksnapzz

3/26/2026 at 6:32:59 PM

That's true, and has been for quite some time. Still: NOx and VOC, but not CO2.

by shmeeed

3/26/2026 at 2:58:04 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...

by testing22321

3/26/2026 at 3:52:34 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.

by shmeeed

3/26/2026 at 1:20:57 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.

by bob1029

3/26/2026 at 2:32:30 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.

by shmeeed