So how are pedestrians wanting to cross the road distracted by seeing a car approaching them on a dull cloudy day with two little lights on? Perhaps you would like to provide a link to a list of those EU countries which have banned them.
I-MIEV were the cheapest on the market when I bought mine.
Actually you want a nice wide curve, not a narrow peak. It doesn't matter too much if that's power or torque.
Think about it. What you want is thrust on the road. Your gearbox is a multiplier; it gives you more thrust for a given torque by gearing down the engine. Until you run out of revs, and you have to change up.
An ideal gearbox would allow the engine to stay exactly on its best speed for any given load. For efficiency you want something close to peak torque, and for a petrol, something close to wide open throttle. (Diesels are better at part load). You want the gearbox to keep the engine right on that ideal engine speed, which is probably close to peak torque.
For acceleration you want the maximum thrust possible. You get that by keeping the engine on maximum power.
Try doing some sums. Assume I want 10kN of thrust (about a ton) at 10m/s (22MPH). You'll be able to work out how much power that is, but in order to work out how much torque you'll also need to know wheel sizes and gearbox ratios.
Andy.
I don't think enough design has gone into the lamp housings in all cases now many have gone LED. Similar now many indicators have a yellow lamp behind a clear lens. When the lamps were clear and the lenses yellow, the hole surface area of the lens would tend to light up yellow.
And as NT says, this can be made worse when they try to combine lamps with some fancy / clever styling when the focus should really *always* be clarity to the observer.
How many of us have nearly gone straight across a small roundabout when the oncoming car has been indicating right but we couldn't see it because of the sun or whatever? I suggest that has been more common for me when the indicator is behind a clear lens or combined in one unit.
You can't generally mistake them when they are like the old Landrover single beehive type units because you also get the position of the lamp as another clue. ;-)
Cheers, T i m
That's what a flat curve means.
The two are intrinsically linked. BHP is simply a function of torque and engine speed.
Daf used to make such cars.
Only neccessary for ICE engine.
My first girlfriends Dad restored a Daffodil and I got one ride in it before it was written off by a lorry when he stopped to pick someone up.
My Yamaha YP250 'Majesty' scooter engine / transmission sound reminds me very much of the Daffodil as they both seem to bare little relationship to the actual road speed (as they would as they both share a constant velocity infinitely variable belt driven transmission (CVT)). ;-)
Cheers, T i m
The Daf (and later Volvo) transmission was a great idea in theory, but it suffered from three problems: firstly its belts were prone to cracking, warping and snapping, and sudden loss of transmission belts (leading to freewheeling) is not something you want to happen at high levels of torque when you are climbing a steep hill; secondly it was large and therefore couldn't be included in the engine compartment, so all Daf/Volvo cars were rear wheel drive; thirdly (in my experience) it was too inclined to change down at the least provocation or the slightest increase in accelerator position, so you had the ridiculous situation where the car hardly accelerated at all when you pressed the throttle and instead the engine got faster and faster in a lower and lower ratio. It's the last thing which to some extent makes all automatic cars more difficult to drive until you get used to them, because the driver is only in control of the engine speed and not the road speed, whereas in a manual car the two are always proportional (no vagueness of a torque converter) for any given gear.
I agree they (CVT's) do take a bit of getting used to and possibly more so than the direct drive of an EV.
On my Yamaha scooter ... you sit at the lights with it ticking over (it's a 250cc single 4/ so it sounds like a 'engine' and not a wasp). ;-)
The lights change and you twist the throttle slightly. The revs lift straight away and the bike starts off (smoothly) and whilst the revs stay the same, the speedo is climbing quickly from 0 to about 40 (not really looked) where the CVT reaches the end of it's range and from then on you are just in 'top' as such (so direct drive to the engine).
Back off the throttle from speed and the engine brakes the transmission till you get quite slow where the transmission drops out and you tend to coast.
Whilst it does require a very different use of the throttle compared with a conventional gear / clutch machine, it is 'fun' because of the linearity of the acceleration throughout the CVT range.
A 650cc scooter (with CVT) would probably give most std road machines a run for their money and I see they are doing an 850 motorbike with CVT now:
Cheers, T i m
ISTR there was a trick you had to learn, to back off the throttle slightly when you wanted higher gearing. That triggered a microswitch somewhere, and the system then started to "change up"...
(a common failure mode was the microswitch would fail, and then you could not get out of the lower gearing range)
Modern ones are much better - firstly by sensing and selecting more sensible gears in the first place, and also by virtue of often having "tiptronic" style manual override so you can override the silicon overload when you want.
Have you not found the brake pedal on your car? That is the ultimate way to control the road speed. ;-)
A manual transmission car will 'run away' on a hill if in a high gear, unless you brake or change down. A decent auto will change down itself to prevent this.
CVTs are the spawn of the devil.
Ford and Fiat tried CV transmissions them for a while but they weren't popular
ISTR someone was making one with steel belts.
Yes I was referring to acceleration under engine power; obviously when slowing down you can use the brakes if simply lifting off the power doesn't slow you sufficiently quickly.
The last auto that I drove extensively, in hilly country, was my dad's Honda Accord in the early 90s. Although I've had a few automatic hire or loan cars, I've not driven down any hills that are steep enough that I'd change down significantly in a manual. The Accord had a separate selector position L (low) which was the only way of forcing it to go into a lower gear for engine braking, but I'm sure modern autos manage without this because they sense when the engine is working in overrun and is being driven by the wheels while the throttle is closed.
As a matter of interest, does a decent auto choose roughly the same gear as you would in a manual when going down a steep hill? I find that autos generally are too inclined to change down when you make the slightest acceleration (*), and I wondered if they were the same when you went down a steep hill, to the extent that you had to brake to prevent the engine over-revving.
(*) In a situation where in a manual I'd stay in the same gear and press the accelerator a bit further.
Driving on twisty single-track roads, I have found that when cars have some form of DRLs or dipped headlights, a) I see cars round corners earlier (because the DRLs are visible through gaps in hedges, walls, gateways even before the car has turned the last corner) and brake sooner; and b) cars see me and brake sooner, for the same reasons.
Even where walls/fences are so high that you don't get any warning of the car before it is facing you, I still find I brake sooner if I see its bright DRLs than if it has no lights.
All this is during the day; at night, dipped/full beam headlights on oncoming cars allow you to see them before they come round the corner.
I would always drive with DRLs in a car that had them, and on narrow roads where there is a risk of meeting someone head-on, I'd use sidelights (or maybe even dipped headlights) during the day if my car didn't have DRLs. Anything that makes my car more conspicuous to an oncoming car, to allow him to brake sooner, has got to be a good thing; and anything on his car which makes him more conspicuous to me and allows me to brake sooner, is a good thing too.
The only lights which I find really dazzling are *rear* fog lights when I'm sat behind a car in non-foggy conditions or when I'm close behind another car in moderate fog. I tend to put my rear foglights on when I can't see any headlights behind, and then turn them off when I judge that a car is close enough behind me that he can see me clearly by my tail lights alone. I wish other drivers would extend the same courtesy.
The same applies to brake lights - I hate drivers who sit with their foot permanently on the footbrake at junctions, especially at night, because when you are right behind, you are blinded by them and need to screw up your eyes to preserve a bit of night vision for when the car in front sets off again. Even in an automatic I would always put the car into neutral and use the handbrake or else into park, so I can take my foot of the brake as soon as I've come to rest. I remember the motto my driving instructor drummed into me: "footbrake to stop the car; handbrake to stay stopped; no exceptions".
They've come on an awfully long way since then. Many more ratios, things like locking the torque convertor after a gear change so it only is really used for starting off and smoothing the change. All down to clever electronics. And if it was a Honda box, they were hardly state of the art even then.
I think anything that isn't 'traditional' and feels different (where different could actually be better once you got used to it) is going to have an uphill struggle but as full autos have got better, then CVT is of less use in cars (where space and weight isn't such an issue as on a motor-bike/scooter).
My first Mrs had a Honda C50LA and that was a full 3 speed automatic (not CVT) 50cc motorbike and it rode just like a car auto. Instead of a fluid clutch it's was a centripetal one (well, 3) but in use it felt the same.
Honda offered a recall on a couple of tiny gearbox components (one being a one-way friction clutch on a layshaft) and because I knew just how 'fine' the engineering was in there, I elected to do the job myself so the local bike shop just supplied me the parts. ;-)
Cheers, T i m
The snag with CVTs was getting a reasonable life from them. Most of the Fords with them were scrapped long before their due date due to 'box failures.
Their only real advantage was they were slightly more efficient than the conventional autos of the day - but those have now been vastly improved. And of course the robotised synchro boxes are the most efficient of all.
I bet. I don't think the (rubber) 'V' belts typically used on motor scooters (inc my 250) don't last 'very long'. Luckily they aren't very expensive, relatively easy to change and don't tend to do any damage if / when they fail.
I remember the auto box on our Mk1 1300 Escort was reasonably 'keen', as was the one on our 2000E Corsair before that. The box on our 1800 Victor was quite 'slushy', as was the box on Uncles 1500 Allegro VDP. ;-)
I bet (I read about the locked clutches).
Cheers, T i m
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