Achates Power Heavy Duty Diesel Program Review

[RodRico]

Not a lot of detail, but more than I've seen anywhere else to date...

https://youtu.be/Az16WAfzZbI

 

[gruntguru]

Impressive. The combination of 50% TE and ultra low emissions is unprecedented in an engine this size.
Seems Hugo Junkers was on the right track 100 years ago.

je suis charlie

 

[enginesrus]

Yes all the good old school stuff works great, nothing new in this design.

 

[TugboatEng]

That's what they want you to believe, engines. They want their competition barking up the wrong tree.

 

[gruntguru]

The uniflow scavenged OP 2 stroke was always known to have numerous thermodynamic advantages.

According to Achates, they have discovered other ideal characteristics, in particular ready control of excess air and internal EGR. As a result, combined with modern external EGR, exhaust aftertreatment and turbo/mechanical supercharging/scavenging, Achates are achieving very good results across the emissions drive cycle with minimal compromise to TE (and therefore CO2).

je suis charlie

 

[RodRico]

I heard they put a lot of work into oil control to overcome the tendency to shed oil out ports (a well known issue with opposed-piston two-strokes), but it turns out they weren't all that clever... at 57:50 in the video, they mention they're using "Oerlikon Likon spray bore coating" which sounds just like the technique used by Mann and Wärtsilä in their big marine engines.

 

[TugboatEng]

Man and Wartsila have OP engines?

Are coated bores a band-aid?

 

[RodRico]

Man and Wartsila have OP engines?

No, I got opposed-piston happy. It's been corrected.

Bore spray isn't a band-aid, it's just complex and seldom used in small engines AFAIK.
I thought Achates was injecting oil through micro-passages between the ports when the ports are open and letting the pistons drag it down the bore. That's what I do.

Interestingly, Volvo cut a patent in 2017 for an opposed piston. I wonder what they plan.
See

https://worldwide.espacenet.com/pat...ublication/US2017122199A1?q=pn=US2017122199A1