bobzilla
bobzilla MegaDork
2/19/20 3:00 p.m.

Rotary Diesel. Came up in conversation here at work where someone was intentionally adding oil to their diesel. Made me think about adding two cycle oil to a rotary for the apex seals..... so could you actually make/have a diesel with spinny triangles?

¯\_(ツ)_/¯
¯\_(ツ)_/¯ PowerDork
2/19/20 3:05 p.m.

Apparently it has been tried.

Short version- can't get enough compression ratio to make it work well.

Hungary Bill
Hungary Bill GRM+ Memberand PowerDork
2/19/20 3:06 p.m.

I think Mercedes made one actually...

 

 

Ooh!  https://en.m.wikipedia.org/wiki/Mercedes-Benz_C111

z31maniac
z31maniac MegaDork
2/19/20 3:10 p.m.

My first guess is "No," because I think it would be difficult to get the compression high enough?

Colin Wood
Colin Wood Associate Editor
2/19/20 3:10 p.m.

Rolls Royce apparently tried to make a four-rotor diesel wankel in the 1970s.

Autocar did a feature on it in their December 1970 issue.

jimbbski
jimbbski SuperDork
2/19/20 3:27 p.m.
Colin Wood said:

Rolls Royce apparently tried to make a four-rotor diesel wankel in the 1970s.

Autocar did a feature on it in their December 1970 issue.

I remeber reading about it as well.  I think they used a supercharger to first raise boost level  so that the rotory could compress the air enough for the diesel fuel to self ignite.

ebonyandivory
ebonyandivory PowerDork
2/19/20 3:33 p.m.

So crankshaft and piston is the high-water-mark of internal combustion engines?

bobzilla
bobzilla MegaDork
2/19/20 3:42 p.m.
ebonyandivory said:

So crankshaft and piston is the high-water-mark of internal combustion engines?

I thought we already knew that. 

ebonyandivory
ebonyandivory PowerDork
2/19/20 3:46 p.m.

In reply to bobzilla :

I figure someone will chime in with a differing opinion 

noddaz
noddaz GRM+ Memberand SuperDork
2/19/20 4:09 p.m.
ebonyandivory said:

So crankshaft and piston is the high-water-mark of internal combustion engines?

Diesel anyway.

ShawnG
ShawnG UltimaDork
2/19/20 4:19 p.m.

The runaway will be spectacular.

codrus
codrus GRM+ Memberand UberDork
2/19/20 4:22 p.m.

I suspect it would also be hard to make the seals sturdy enough to withstand compression ignition -- look at how quickly detonation kills it compared to a piston gas engine.

 

Driven5
Driven5 UltraDork
2/19/20 4:30 p.m.

Liquid Piston has built a running (proof of concept) diesel version of their rotary engine architecture.

j_tso
j_tso Reader
2/19/20 4:43 p.m.

The Rolls Royce engine sure looked cool though. 

Air comes in from the bottom and is compressed by the big rotor into the smaller chamber where diesel is injected.  

z31maniac
z31maniac MegaDork
2/19/20 4:49 p.m.
ebonyandivory said:

In reply to bobzilla :

I figure someone will chime in with a differing opinion 

I mean they are functionally the same. The compression force pushes the rotor, which turns the eccentric shaft, which delivers power to the flywheel. 

But there are also people who believe the Renesis, for example, is really 2.6L based on use, and then it's output and fuel economy really makes no sense. 

Toyman01
Toyman01 GRM+ Memberand MegaDork
2/19/20 5:58 p.m.

This was in the works in the before the company went out of business. They had a display at the International Boat Show in Fla. in 2002. Power ranges from 150 hp to 3000 hp and the ability burn just about anything. I don't think they every got beyond the prototype stage. They were supposed to have a boat and several engines at the show. 

Petrolburner
Petrolburner Dork
2/19/20 7:16 p.m.
ebonyandivory said:

In reply to bobzilla :

I figure someone will chime in with a differing opinion 

 

 

 

 

 

 

I saw this the other day, looks awesome!  I wonder how a 6 piston 3 cylinder supercharged turbo-diesel sounds?

 

 

 

https://www.youtube.com/watch?v=UF5j1DvC954

 

 

 

ebonyandivory
ebonyandivory PowerDork
2/19/20 8:32 p.m.

In reply to Petrolburner :

Didn't we have a thread about something like that here recently? If I remember correctly there was a company putting that type of engine in new F150s

Recon1342
Recon1342 HalfDork
2/19/20 9:16 p.m.

In reply to Petrolburner :

The opposed-piston engine design has been around since the '80s, so it ain't exactly new.

Oh, and by the way- that would be the 1880s, not the 1980s. 
 

I've had the pleasure of hearing an old Fairbanks-Morse locomotive crank up. They certainly sound unique. 

ShawnG
ShawnG UltimaDork
2/19/20 11:47 p.m.

Junkers had opposed-piston aero diesel engines pre-wwII

Napier built the Deltic: 

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