[Music]
give it a little give a little
all right charles time to be serious
i'm jason with engineering explained and
hey i'm charles from humblemechanic.com
and in this video we're going to be
explaining how direct shift gearboxes
work and we're going to be starting with
the clutch two clutches in fact
oh and we're wearing gloves because
charles is going to get his hands dirty
and i wanted to feel included yeah we we
got to make sure jason fits in so
you're looking good in those gloves it's
a little dangerous usually i just deal
with white boards and they're very safe
do you need gloves for white boards
you get like a little
yeah i get a little little fade on my
hand and i have to take a shower
afterwards to clean up everything that
is too much i don't know that everyone's
a lot of work
all right anyways back to the clutch
all right so
this is actually the dual clutch pack
out of a volkswagen transmission this
particular one came out of a
i want to say a 2013 passat
normally this isn't something that i'm
able to keep um it has a core charge on
it but but you stole it but i did not
steal anything um nothing was stolen in
the making of this video sure okay uh
this actually the customer hit something
and uh i was able to the customer hit
something yeah i was able to keep this
so this is really cool we're excited to
kind of explain how this works and show
you guys all about the dual clutch so
this is the clutch housing and this is
going to be rotating with the flywheel
in this case it's a dual mass flywheel
that this bolts up to and both clutch
packs are inside of this so and these
are multi-plate clutches
so
i'll let charles explain what's going on
in the inside here so basically what
happens is
there's two like jason said there's two
clutches there's an inner and an outer
clutch volkswagen calls these k1
and k2
k1 controls the odd gears and k2
controls the even gears
now there's an electronic unit that
controls the fluid flow to this and what
it'll do even though this entire mass is
rotating with the flywheel it can lock
one or
either the inner clutch or the outer
clutch and rotate one of two
input shafts to the transmission
so we're looking at the overall gear set
of this transmission you can see it's
basically a manual transmission this is
our two input shafts you can see that
i'm rotating this one independent from
this one and that's where the that's
where the dual clutch comes in one
clutch controls one the other clutch
controls so this is two separate shafts
right here though they're concentric
they're one on top of the other if this
were a traditional manual transmission
this would all be one one piece okay so
this is the input shaft for the
transmission and it's actually two
shafts as we mentioned earlier so one is
around the other and basically what
happens is you've got these two clutches
here now this right here which splines
to one of the shafts this one
rotates the inner clutch as you can see
there
and then this outer
piece of housing here rotates the outer
clutch
so what happens is when you stick this
on here
you can see that it only rotates with
the upper shaft
and then as i take this and put that on
top
that rotates with the other shaft
so that's how you're controlling the odd
gears and even gears with these two
shafts so here's a more detailed look at
these multi-plate clutches now these are
wet clutches which means they are housed
in oil and as you can see here you've
got the alternating friction discs and
plates this is the inner clutch and then
you've got the same thing for the outer
clutch
so here you can see the outer shaft
which rotates with the inner clutch and
then the inner shaft
which rotates with the outer clutch
as we rotate it around we have the
output shaft number one and this has
gears one two three and four
these are the selectors that control the
collars
they sit in the tubes right over here
and for example
that would be first gear
we're already engaged in second gear so
how do you know which gear you're
looking at here so when it comes to a
manual transmission the bigger in size
the gear the lower the gear number so
this is going to be first gear
second gear is down at the bottom then
we go third fourth and five and six are
actually on output shaft number two okay
as we rotate this around we come around
to the differential and i set the uh
axle cup in here just to kind of give an
example of where the axle would be in
relation to this entire transmission now
we actually have the second half of the
case completely removed
just so you guys can see this obviously
it's all in case you wouldn't be able to
see anything
if we had both cases installed as we
come around here's output shaft number
two
this has reverse
five and six
and they're actually different size
collars so we engage this is actually a
broken transmission but we engage gears
this way
here's reverse engaged
down there uh this is your reversed
shaft remember we have to rotate the
gears the opposite way when we're going
backwards backwards
as we come back around one really cool
thing
is there's these wheels all throughout
these gear sets and this actually lets
the um the mechatronic unit know exactly
where
each position is and what's rotating at
what speed
and it's really fun to play with
this is the selector that's used to
select each gear
there's little pistons inside the case
one we'll move it up and then on the
corresponding side on the top we'll move
it down and this piece right here is
actually a
magnetic position sensor so the
mechatronic unit knows exactly where
each selector is throughout the process
so you can see here we have
first gear engaged i'm actually turning
the input shaft of the transmission
this is actually input shaft one
and so here's the output going to the
differential which will then send power
to the driven wheels right so power flow
is coming actually from the back here
up to this gear you can see at the very
top of your screen that i'm turning
to gear one
down to the differential and then out to
the wheels your wheels would actually be
here and then in the
opposite spot on the bottom of the
screen so if we're to run through if
we're to engage first gear so
everything's going to be nothing's going
to be selected when we're selecting
first gear this color here will engage
first gear and then you're sending power
to the wheels with first gear engage now
while you're doing this as you're
starting it to the higher rpms and the
clutch is anticipating you shifting the
second the second gear collar will
engage while the first gear is still
engaged but remember the clutch that
this second gear is engaged to
is disengaged from the engine whereas
this one is engaged
so once you actually do shift gears you
tell the computer hey switch gears you
press on a paddle shifter or whatever it
may be then this will disconnect
and all the while
your clutches are switching which one's
sending power to
this differential here so this one will
start receiving power while this one is
still receiving power and you'll kind of
have this overlap of where you're always
going to be getting torque but that
torque is going to decrease from this
one and increase this one and then send
power to the driven wheels through this
differential and that is why a dsg will
always shift faster
than most drivers definitely better than
a manual car or a automatic gearbox with
traditional planetary gears because
you're always going to have some torque
being delivered and you can pre-select
the next gear up or the next gear down
depending on what the computer thinks
you're going to be doing next and that
allows you to have a much quicker shift
so what i have in front of me here is
the mechatronics unit and basically what
this is responsible for is the logic for
the transmission so you may be wondering
how does it know which gear to
pre-select uh and there's some logic
that goes into that and basically some
simple examples are let's say you're in
second gear and you're flooring it the
rpms are increasing it's going to go
ahead and pre-select the higher gear
third gear so you can get into that one
very quickly let's say you're in fifth
gear and you're hard on the brakes well
then it knows to downshift for the next
one so it'll go ahead and pre-select
fourth gear and i think that really
explains why there's some sort of
misconceptions about you know this
transmission itself because
this is a manual transmission that just
happens to be automatically controlled
so that may explain why you know certain
criteria of driving may a driver may
experience you know a delay or a weird
shift because the computer brain right
here can really only predict a driver's
input to a certain point right so if it
pre-selects the wrong gear and you chose
to go the other direction with the gear
shift then you may feel you know a
slight delay because it has to
compensate for that change my experience
that really shows itself when you're
accelerating and let's say the light
turns red and you let off the gas and
you know magically the light turns green
really fast you hit the gas again that's
when you really experience that delay
because the the transmission computer
thinks you're going to do one thing
because it's seen you know a series of
seconds go by with this input from the
driver and now the driver flips that on
its head and matches the throttle now
the transmission has that split second
of uh i don't know what to do oh okay
now i'm good let's go and that's i think
where a lot of people sort of have this
conception of a dsg being you know jerky
or finicky or whatnot
so thank you guys for watching if you
have any questions or comments you know
what to do and thank you charles for
having me here i flew all the way from
oregon to north carolina just to check
this guy out this guy i love if you
haven't yet watched our video on the vr6
you should check that out that's a great
video i think it broke the internet by
the way broke the internet it's better
better
way better than that other yeah anyway
guys thanks for watching and we will see
you next time