Zero Speed Automatics

[70cuda88]

I heard this term today and wondered what it meant. does it mean there are no gears? i thought all engines had gears?

[Ferrer]

I heard this term today and wondered what it meant. does it mean there are no gears? i thought all engines had gears?

I guess they were refering to CVT gearboxes. Which means continously variable transmision. The were invented by the dutchies, and from here someone with more technical knowledge than I will be able to explain how they work.

[taz_rocks_miami]

I heard this term today and wondered what it meant. does it mean there are no gears?

Here is an article on CVT transmissions: http://auto.howstuffworks.com/cvt1.htm

i thought all engines had gears?

It's the transmition that has the gears, not the engine.

[70cuda88]

engines and trani's as a whole is what i was reffering too

[Matra et Alpine]

Never heard the term.

But taking the semantics of the phrase then I woudl suspect it refers to a transmission capable of providing torque at zero speed.

So "old style" autos get it with a slush-box (torque convertor).
Modern computer controlled autos manage slip of clutch plates.
Not sure how modern CVTs behave in engaging drive from standing start.

[The_Canuck]

But taking the semantics of the phrase then I woudl suspect it refers to a transmission capable of providing torque at zero speed.

I think it refers to it having no gears. You know how 6speeds, 5 speeds and so on all have different numbers of gears...a cvt wouldn't have any, hence, Zero.

[Matra et Alpine]

I think it refers to it having no gears. You know how 6speeds, 5 speeds and so on all have different numbers of gears...a cvt wouldn't have any, hence, Zero.

IN reality a proper CVT has infinite gears.
So if someone is calling it "zero" then they're dumb

[Waugh-terfall]

So, if you're driving a car with a CVT gearbox, such as an Audi A6 Avant or MG F do you feel a gearchange or does it just feel like one long gear as it were?

[Dino Scuderia]

Zero-speed is a term used for transmissions describing points at which synchronizing takes place, also there are zero-speed sensors. I don't believe there is a 'zero-speed automatic transmission' per se.

[Matra et Alpine]

So, if you're driving a car with a CVT gearbox, such as an Audi A6 Avant or MG F do you feel a gearchange or does it just feel like one long gear as it were?

NO in todays CVTs you feel gears.
But that's because of DAF's Variomatic experiences
People didn't feel comfortable with the way a CVT drives when "optimal".
ie the engine revs to peak torque and then stays there while the car accelerates !!! All the way to max speed NO perceptible gear change.
Also, people associate the kick when changing gear with "speed"

SO in the dumbing down of CVT we have infintely variable transmissions which the computer will only place into 5 or 6 positions and use the engine revs in that posisiton before "changing" up/down.

[Ferrer]

So, if you're driving a car with a CVT gearbox, such as an Audi A6 Avant or MG F do you feel a gearchange or does it just feel like one long gear as it were?

The MGF was available with a CVT gearbox?

[Knuto]

Maybe you meam seamless shift from f1. Those boxes operate with zero (almost zero) shift time so there is a constant flow of torque. Zeroshift makes gearboxes like that, and as you can see on the graph below there is zero shift time. First graph is standard Cerbera and second is Zeroshift equipped Cerbera

[IWantAnAudiRS6]

The MGF was available with a CVT gearbox?

Er... not entirely sure on this, but the TF for sure was offered with the Stepspeed, also available on the ZR, ZS and ZT...

[Ferrer]

Er... not entirely sure on this, but the TF for sure was offered with the Stepspeed, also available on the ZR, ZS and ZT...

But wasn't Stepspeed a conventional torque converter auto?

[IWantAnAudiRS6]

But wasn't Stepspeed a conventional torque converter auto?

I think it was a semi-auto or something. Either way, not only was it pointless (on an MG, for God's sake), it was also crap.