I'm tempted to say six forward gears on the CC3 is one too many.
But I've not driven one with five forward gears, so it's difficult to judge.
|
I've had my 1.4 tsi Golf for around 6 months now, and am generally delighted with it.
However, the dsg auto box takes some getting used to. Not at speeds above about 20 mph when it is generally excellent but at low speeds and from rest.
For example, from rest you have to "squeeze" the throttle open in order to pull away without a jerk. If you just prod it you will need to collect your head from the back seat.
Also, if accelerating from the overun ( say when entering an island ) again it can be very jerky.
I find I even get occasional ankle ache due to having to provide precise throttle inputs.
Even SWMBO ( who has a 6 sp dsg Eos ) finds it a bit sudden.
My dealer has checked it out and decares that all is well.
Any other uses have similar thoughts ? ( hello Mr Tack )
|
The auto box in brother's Honda Civic behaves in a very similar way.
I don't drive the car a great deal, but I think some of the low speed jerkiness could be removed by judicious use of the steering wheel paddles.
|
My first Accord was a Hondamatic with a brilliant torque conversion system and just one gear that took it briskly from 0 to an indicated 110mph. It did also have a low hold and an optional overdrive that wasn't any faster but lopped off 500rpm. Nothing more seemed to be necessary.
I guess for today's deskbound generation, that does nothing in its spare time but watch TV, all that gearchanging between 5, 6, 7 or more speeds is useful exercise...
|
|
|
|
Not if you've got a flexible engine with a good spread of torque across a wide rev range - typically a turbo or large capacity petrol.
I've got a large capacity petrol, and for fuel economies sake, I'm glad it has a 6th gear. It can cruise at 60mph with just 2000rpm. And yet, knock it into 3rd and it flies. Good news all round!
But what I was particularly thinking of is modern diesel engines with relatively narrow power bands, they really do benefit from 6+ speeds. Especially since they are so responsive on lower revs, as long as the revs are high enough for the turbo to be kicking in.
|
|
Original 911 Turbo had only four gears when averything else with more than 100bhp had five. Just goes to show what you can do with oodles of torque.
|
|
If you don't want many gears, buy an electric car :o)
|
If you don't want many gears buy an electric car :o)
or even a small petrol engine, powering a generator which in turn powers an electric motor transmition which does away with clutch and gearbox.
|
or even a small petrol engine, powering a generator which in turn powers an electric motor
Dr Ferdinand Porsche had an idee fixe about that sort of hybrid drivetrain AE. Was designing military trucks and tanks with that system through both world wars, and some prototypes and a few production examples were made.
No one has made a viable car version yet as far as I know. They may be close by now, but we have yet to see the version that will make us think 'here, at last, is the real thing... or on reflection perhaps not'.
It's an attractive idea, a single-speed, super-economical oil-fired engine making just the right amount of electricity all the time. But you still have to store the juice, meaning batteries, heavy or expensive or both, and not everlasting. Nice idea but... if the Professor didn't manage it we need a, what do they call it, ah yes, 'technological breakthrough' before it will stand up and walk or better still run.
|
No one has made a viable car version yet as far as I know.
Apart from the Toyota Prius!
|
Apart from the Toyota Prius!
But on that the generator charges the batteries. On a diesel-electric train, the generator drives the motors directly; there are no heavy batteries.
Edited by Focus {P} on 22/09/2009 at 12:03
|
But on that the generator charges the batteries.
When running at low speeds, some of the energy from the petrol engine is diverted to the generator which drives the electric motor directly. Depending on how much torque is required in this driving mode, the vehicle is driven by either the electric motor alone or the petrol engine and the electric motor.
In the second case the electric motor supplies torque to support the petrol engine, which would otherwise not have the torque to drive the wheels, and thereby acts as a torque converter. This is how a Prius gets away without having a gearbox.
|
>> But on that the generator charges the batteries. When running at low speeds some of the energy from the petrol engine is diverted
I stand corrected :-)
The point is, why can't you have a Prius without the heavy/costly batteries?
|
The point is why can't you have a Prius without the heavy/costly batteries?
The batteries are used to store braking energy to power the electric motor without the engine running. One of the nicest features of the car is its ability to glide along at up to 50km/h in virtual silence - great for worrying pensioners in supermarket car parks!
The engine is also used to "top up" the battery so the electric motor can be used to overcome power spikes, such as additional acceleration for overtaking.
Damn clever piece of engineering the Prius.
|
either way, the point is we dont need a gearbox,gears, clutch or DMF. Its not such a radical leap to replace them all with an electric motor, powered by a diesel generator.
|
Damn clever piece of engineering the Prius.
No doubt, but does it actually give significant advantages over an economical diesel? Why not a reasonable size diesel (so no need for a power reserve) running at an efficient rpm driving a generator driving the motors directly? How impractical would that be?
|
No doubt but does it actually give significant advantages over an economical diesel?
1. Ability to store the braking energy that would otherwise be wasted and reuse it as kinetic energy in the electric motor. Improves economy, saves on brake pads;-)
2. No emissions or noise when the car is stationary (except from the occupants).
3. Mega starting torque from zero rpm and absolutely no turbo lag.
4. Ability to drive around in silence using only the motor.
5. No gearbox, clutch or torque converter.
6. No horrible diesel rattle.
7. Far nicer to drive around town than any "economical diesel" I know of, due mainly to the above points.
|
>> No doubt but does it actually give significant advantages over an economical diesel? 1. ...
Fair enough - I take it you like them :-)
|
>>>>This is how a Prius gets away without having a gearbox
I think you'll find that a Prius does indeed have a gearbox! Its a CVT
|
|
>powers an electric motor transmition..
It's used on heavy earthmoving equipment, particularly haul trucks.
Try changing a wheel on one of these beauties, those tyres are about 12ft in diameter and cost more than your average hatchback. The motors are in the rear wheels.
tinyurl.com/l48rle
The driver's cab is at the top of the RH stairway and he's blind to anything less than about 30ft infront of him so it's wise to keep out of his way.
Kevin...
|
IMHO cars are following pushbikes where number of gears is some sort of virility symbol. The 21 speed bike actually has very little more range then ten or twelve well chosen ratios, just too many duplications and overlaps.
Cannot see how the average family car needs more than five. Top might be an overdrive with smaller engines but six or even seven just add boggling complexity.
|
Cannot see how the average family car needs more than five. Top might be an overdrive with smaller engines but six or even seven just add boggling complexity.
Overdrive was magic on the Triumph 2000/2.5PI in the 1960s - much of the rest of the car was poor - the 2.5s were petrol injection from Lucas & went on fire fairly often!
For the youngsters of the BR
O/Drive needed about 25% less revs than the gear you were in, clutchless silky smooth up or down............magic.
|
>or even a small petrol engine, powering a generator which in turn powers an electric motor transmition which does away with clutch and gearbox<
There's nothing new, etc, etc. Tilling-Stevens was making petrol-electric trucks and London buses circa World War One, and went on making them into the 1930s, when the economics of diesel did for them.
They then designed a fantastic twin-supercharged horizontally-opposed three cylinder two-stroke diesel lorry and bus engine that made a noise that would shame a racing car. But that's another story...
|
They then designed a fantastic twin-supercharged horizontally-opposed three cylinder two-stroke diesel lorry and bus engine that made a noise that would shame a racing car. But that's another story...
Ahh, the old TS3 which graced so many Commers! Together with the Foden 2-stroke (I grew up next to Hoveringham Gravels' yard) one of the most evocative sounds of the 1960's commercial scene.
Now that was a motor where you DID need a double-figure set of cogs in the box!
|
For the youngsters of the BR O/Drive needed about 25% less revs than the gear you were in clutchless silky smooth up or down............magic.
You don't have to go back to the 1960s to find overdrive. I have it on both my vehicles (2004 Almera and 1997 Hiace), which use a 3-speed auto with overdrive. And I agree, it's very good.
|
On my MKII Mondeo automatic I only have a button to deselect "O/D" and a dash sign then says "Sport" but I guess this does not really count as overdrive.
IIRC later models dare not display "Sport" :-(
|
Overdrive on third and top on the Triumph 2.5 PI which gave it six forward gears, proving the old adage about there being nothing new under the sun.
Great fun too, with its James Bond-style switch on top of the gearstick.
The order of the ratios was third, overdrive third, fourth, overdrive fourth.
We described the gearchange sequence to customers as 'three, three-and-a-half, four, four-and-a-half'.
Similar set up in the TR6 (I think) sports car, but operated by a short column stalk.
|
Delightful to use... changing up to 4th as 100mph went by.
Allegedly.
|
Who knows where it will end?
One of the first vehicles I ever drove in the sixties was the old Ford Thames van which had three forward gears
....and then for years until late 80's 4 gears were the norm
...and then 5
...and now I have 6 forward gears on the Accord.
Returning to a 6 gear manual after an Automatic Accord Tourer took a bit of getting used to but when I test drove the car the slickness of the 6 speed Honda gearbox was one of the things which attracted me and I loved the response from 2.4 litres of iVTEC engine when the toe goes down ...
As another John H says above , changing up to 4th as 100mph goes by (and watching boy racers disappear in the rear view mirror ) is quite exhilarating ( allegedly) ....
|
I fondly recall driving my parent's 1953 Chevrolet BelAir to university in 1971 with its 2 speed Powerglide automatic transmission (the 1953 was the first year where it would automatically shift from low to high as you accelerated). As I recall, the back seat was another well loved feature.
Canuck
|
|
|
|
|
|
