hello everyone and welcome i recently
saw a jalopnik article about an auto car
article from the 1970s that was talking
about a rolls-royce wankel diesel engine
and this was so fascinating that i
thought i had to make a video about it
so that's what we're going to be talking
about here and basically uh this engine
the goal of it was back in the 1970s
rolls-royce wanted to make this as a
military engine for use in the military
and their goal was high power high
efficiency in a very compact size wankel
engines of course
have the benefit of being small and
power dense diesel engines have the
benefit of being efficient so kind of
combining all of that into this one
amazing engine well the challenge that
they ran into is that wankel engines are
hard to design with a high compression
ratio and their solution you could
supercharge it you could turbo charge it
they decided to add a whole nother
wankel engine rotary in there basically
in order to use that as a supercharger
or as a compressor this is just a
positive displacement compressor that
forces more air into this combustion
chamber right here so this one is just
for transferring air this one is
actually where combustion is occurring
and so basically how this works is the
ratio of the displacement of this rotary
right here versus this one right here is
going to give you your increase a
multiplier for your compression ratio so
this lower stage is
3250cc cubic centimeters versus this
upper stage is 1265cc
you divide those two and that means your
compression ratio is effectively being
multiplied by 2.57 now you may be
thinking wow this is huge why would they
use something so big to compress air for
that other stage but actually they
looked into just doing a single rotor
with a high compression ratio simply by
using the geometry of how it's designed
and in order to do that it requires a
really large footprint so a single rotor
with a high compression ratio would be
very similar in size to these two rotors
using this to increase your effective
compression ratio so overall the size is
actually pretty compact even though it
looks like it's basically enormous now
another challenge they ran into is they
decided to use direct injection but
there wasn't too much research out there
on using direct injection in diesel
ankle engines so they ended up trying 30
different combinations for combustion
chambers they tried six different
injector positions uh basically over a
hundred different combinations that they
tried out and settled on one that worked
best
you know much easier in a piston
cylinder device to just have that
injector directly on top as that piston
comes up right in the middle of that
circle perfectly distributes the fuel
versus you know having that winkle sweep
by is much more challenging
in order to have that perfect air fuel
mixture and then have that ignite when
you inject that fuel
so how does this thing work well
basically you have your air intake down
here at the bottom so this bottom rotor
rotates about this blue eccentric shaft
right here as that rotates it compresses
that air into this stage right here so
then this rotor then rotates and
compresses that air then you inject that
fuel you have combustion occur the rotor
continues to rotate about that separate
its centric shaft right there in blue as
it rotates uh the exhaust is then pushed
out you know the that's the power stroke
right there is rotating that then the
exhaust is then pushed out and actually
continues to do useful work rotating
that second compressor with that exhaust
and then finally dumped out this exhaust
right here so that cycle just basically
continues and you know both of these are
rotating about and you're creating a
good power within a pretty good
footprint
so the rolls engine is the 2-r6 engine
and basically it was set up with two
banks on two stages uh so overall this
was basically a four rotor engine uh you
know sorry rob dom they were doing this
back in the 1970s producing 350
horsepower at 4 500 rpm and only
weighing 939 pounds now 939 certainly
sounds like a lot but remember this is a
diesel engine and this is back in the
70s at the time it was way smaller and
way lighter than similar diesel v8s that
had similar output so the v8 you know
diesels were much bigger
similar much more weight a similar
output you know but of course that
drawback of their size and weight so
they did actually achieve their goal of
having something that you you know was
powerful efficient and in a much more
compact size it's unfortunate you know
that ultimately uh the research kind of
died out and so we don't have cool ankle
engines running around today perhaps you
know if more companies invested in it we
could have them but hopefully mazda does
come up with something in the near
future so that would be cool to see you
know this engine kind of live on but
really neat concept you know it was it
was fascinating to hear about this using
a separate basically rotary engine just
as an air compressor for the main rotor
so very cool to see if you guys have any
questions or comments feel free to leave
them below thanks for watching should
they keep watching more videos bucket
they should probably keep what oh god
hey
that's all right
it's not okay huh
okay i'll let you get back to your nap
you