I keep seeing small cars sold as semi-auto. Things like Clios, Micras, Corsas etc.
Which bit is semi?
What does the driver have to do that they don't have to do on a convential auto?
Can they be driven on an ordinary auto licence?
AFAIK Anything with a sequential box that's capable of being fully automatic, can.
I was told things like BMW's SMG boxes require a manual licence. Even although they have an auto function.
Strictly speaking a semi auto just dispenses with the clutch - you still have to select the gears manually.
Dunno.
Hmm, odd one that. I've had a few, therefore am unable to comprehend things properly. Perhaps someone ought to do some research.
I drive a Fiat Panda Dualogic which is a semi-automatic.
There is no clutch pedal and it has two modes.
a) Automatic - it changes up and down on its own just like a conventional automatic with a torgue convertor. On the Fiat some clever electronics do the gear change and operate the clutch.
b) Manual - as above but you move the lever forward to change up or back to change down with the electronics doing the clutch.
An yes it is great to drive especially in heavy traffic where I choose auto or on twisty A roads where manual is the way to go.
So how is that a semi-auto? Apart from marketing speak, obviously.
Conventional torque convertor autos are available with full manual override - think the first was Porsche with the Tiptronic, but BMW and Jag And others offer much the same.
What is being described in these ads are the ASM (Automatically Shifted Manual) gearboxes. If used in the fully automatic setting, it's pretty much just like driving any other automatic (except the gear changes do feel a bit different, as it does take longer to change between gears than a conventional automatic).
But most ASM boxes, also have the ability for the driver to select the gears manually (obviously it's programmed with defined limits to protect the mechanicals), in effect giving you a semi-automatic function. It does offer more gear choice than what you'd traditionally have on a conventional automatic, and ASMs are generally more effiecient due to generally being lighter, having more gears, and not relying on a torque converter.
If you take an test in one of these you'll only get an entitlement to drive autos but that doesn't necessarily mean that an auto licence will allow one to drive one normally.
To me "semi-automatic" means part (half) of the normal gearbox function is automatic and this usually means that there's no clutch. ..but is a semi-auto with a full auto mode the same as a full auto with a semi-auto mode???
The message from "Ian" contains these words:
Ah, that's the bit I need. The wife can't do manuals, and quite a few more recent second hand "automatics" say "semi-auto".
Are they all capable of full auto mode, anyone?
On 2007-02-04, Dave Plowman (News) wrote: [snip]
Aren't some of the BMW ones mechanically the same as manual transmissions, but with some kind of robotic shifting mechanism (complete with "throttle blipper" presumably)?
Tiptronic on the other hand is just an auto box (epicyclic gears), except they put some buttons on the steering wheel as well as that selector thing autos usually have-- which although it looks like a big lever, is basically just an electrical switch.
once again some are, but for instance in heavy traffic the system may stop working for a few minutes (basically to "stop the clutch burning out")
a proper auto you could leave in drive with the handbrake on for 15minutes ina big queue (I admit its not good for the auto g/box)
Also reversing into a tight parking space on an incline is the major test I find for these systems
Blimey, things ain't moved on much. The last time I used public transport was as a kid in the late 70's and the old double-decker bus I remember watching the driver flick a small lever to change gears with no clutch. I think there was about a 2 second delay in flicking the lever and the gears changing, so I guess that's probably been modified a bit.
And unless a twin clutch type rather rougher changes.
Exactly the same as the Steptronic on my 'normal' auto.
As I said in my earlier post, many TC autos have this facility these days. Nor is it new - the first Mini auto had this too - and I'll bet there are other examples. But it tends to be a 7 day wonder - autos being so good these days that you're usually best to just let them get on with it.
Eh? Depends on the auto. Most TC ones have 5 or more these days. Think 8 is the current maximum.
On many the TC is only used for starting off and to cushion changes after that it's locked.
I've a feeling the whole thing is market speak - 'I don't drive an auto, I have an SMG or DSG'...
Yes. And complete with rough gearchanges.
Audi and others use still a synchromesh box but with effectively two layshafts that the output is taken off. And two clutches. So say 1,3 and 5 are on one shaft and 2 and 3 on the other. A sequential change is done by swopping clutches as both gear trains are already engaged. So no gap in power delivery or jerk on a fast change.
As is the selector on an SMG transmission - the gears are swopped by servos.
On the pseudo-SMG yes but if you get a *real* SMG no.
Although almost everyone I know who has a Tiptronic type box soon gets tired of playing with the manual change and starts to use the box exclusively automatic.
I know it's horses for courses, and everyone has their own ideas, but having now owned four fully automatics I would never never ever go back to the hassle of a manual gearbox. On the odd occasion these days that I find myself driving a manual (usually hire cars), I find them a pain in the backside. Just *why* does anyone actually 'want' to constantly pump their left leg up and down and waggle a stick about when a modern auto box does it all for you? It's beyond me! Bit like someone preferring to wash clothes by hand instead of in the automatic washing machine!!
Uno-Hoo!
You mean a motorbike type box? Doubt many car makers would allow the crudeness of dog clutches instead of synchromesh, though.
From what I've heard, the ones that are a conventional clutch/manual box with electronics are horrid, the DSG (with two clutches but no TC) is very good (very fast changes), the Audi CVT-with-stepped manual is OK but not as reliable as one might hope. It seems the torque convertor will be with us for a while yet. I'm not convinced a conventional clutch with an auto/semiauto is such a good idea: a TC spends a lot of time slipping (which it can do without wear) when you're crawling in traffic, which is the time I always wish I had an auto.
Sounds like a bodge to me.
Opinions differ on that- is there more wear if you shift in and out of D? Dunno. Thing is, a coventional TC+Epicyclic box will just be stirring fluid, not burning a clutch plate.
Why? Is it that it's hard to control speed? I've never driven one.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.