I'm still puzzled why the Toyota & Lexus hybrids have combined drive.
Why not just use electric traction motors to drive the wheels, and have the engine running only to top up the batteries when they need it? That way you could have a much smaller engine, and smaller batteries because you've got charging on tap when its needed.
I thought the early 90s Volvo ECC gas-turbine hybrid was a great idea, the small turbine just drives a generator so it can run at optimum rpm at all times, for a clean exhaust.
Also, I really want a jet car :-D
|
>>Why not just use electric traction motors to drive the wheels, and have the engine running only to top up the batteries when they need it?
Sounds ideal doesn't it?
The problem is that you would have to size the traction motors to cope with worst case conditions, and so, for most driving, they would be seriously over-sized, and so, it wouldn't be as efficient a solution as you might first imagine.
A combined drive allows each drive to be sensibly sized, and when acting together can overcome worst cases conditions, like steep hill starts, long mountain climbs, etc, but, are efficiently sized when running alone propelling the vehicle under relatively lightly loaded cruise conditions.
|
|
|
Again not an expert on this, but I'd assume the batteries have a maximum charging current
which may mean unless you have many batteries in the car, that only a very small engine is needed and it may need to run for many hours to give you 1/2 hour of electric only driving.
Also you cannot charge a battery at the same time as drawing high currents from it, so you would need to have a bank of batteries on charge and another bank being used to supply power OR the batteries only recharge when not driving the wheels (ie downhill) which happens in current hybrids via the motors acting as generators. If going slow in a hybrid and batteries are weak, motor will fire up anyway from what I have read about them.
Gas - turbine - sounds great but would need batteries as well since Cars accelerate and decelerate all the time and gas turbines like to run at constant and high revs otherwise they become inefficient. Turbine - batteries - motors - generators all in one car sounds very expensive at the moment.
|
thanks both -- good points.
Although the ECC prototype was only 75kg heavier than the equivalent Volvo 850, and with advances in battery & electric motor technology over the last 16 years I bet it could be made a lot lighter!
|
|
|
I seem to recall recently about the development of flexible photo-voltaic solar panels.
A hybrid car covered in those would at least top up a little when parked in daylight away from base.
|
|
Has anyone worked out who is going to fix these things? Some garages cant even service or fix current cars properly.
|
|
Haynes have put out a manual for the Prius, I'd actually quite like to read it to see what the owner CAN actually do ...
|
|
Would any of the above buy a 3 year old, out of warranty, on board gas turbine charged, battery powered, electric motor driven, car? Fitted with electric brakes with regeneration, thermoelectric exhaust, photoelectric roof and bonnet and also fitted with a mains charging lead should there be a pressing need to transfer ones carbon output to a coal fired power station.
|
If it had a gas turbine, I would :)
I'd love to have a jet car!
|
We'll all be driving air powered cars one day anyway. I wonder where taxes will be applied to make up for the shortfall?
news.bbc.co.uk/1/hi/world/europe/2281011.stm
|
That's where your road pricing comes in.
Instead of paying 8p per mile in fuel tax you'll pay up to £1.30 per mile road charges.
|
|
I seem to recall recently about the development of flexible photo-voltaic solar panels.
Not that effective in the UK, especially Wales and Scotland ...
And, park it in Liverpool, and when you return not only is the car on bricks, but the valuable solar cells will have gone walkies down to the local pub ... [Runs for cover]
But seriously, the weight of a solar panel might offset any advantages.
|
I think hybrids are with us to stay and that when diesel/electric hybrids hit the market their real benefits will become apparent.
One disadvantage I've heard for hybrids is that once they are cruising along a motorway, they are less efficient than a car with mechanical drive. So why not have a diesel hybrid that normally works with electric drive but shifts to a mechanical 'lock-up' when cruising at over, say, 55 mph AND the battery is fully recharged?
|
Quote:.....>>>"I'm still puzzled why the Toyota & Lexus hybrids have combined drive. "
Am I right in thinking that thre regenerative braking system is able to recover about 50% of the energy used to accelerate the car, and that the petrol engine provides the other 50% to maintain the 'Synergy' drive? The key feature of their hybrid system is the regenerative braking and how best to integrate that with the power from the petrol engine.
Quote:.....>>> I seem to recall recently about the development of flexible photo-voltaic solar panels.
Photovoltaic 'tarmac' for car parks would be good - then you could plug the car in to recharge while parked.
Edited by Sofa Spud on 04/06/2008 at 17:10
|
Photo voltaics use Iridium which is an expensive and rare element. If there was a surge in demand for these devices the price would go higher and there is some question on whether all the demand could be met. Photocell manufacturers are looking at alternatives.
The best photocell is still a leaf...so perhaps one day we would have a leafy car charging the batteries..until autumn comes...umm Ford fOAKus and Lotus FLOWER. (sorry couldn't resist it!)
|
Photo voltaics use Iridium which is an expensive and rare element. If there was a surge in demand for these devices the price would go higher and there is some question on whether all the demand could be met.
I read that the cost of offshore windmills has sky rocketed due to increased demand allowing manufacturers to increase prices.
Regarding the Prius, by all accounts it is no more efficient in terms of mpg than a comparable diesel car. I would have thougt that removing the heavy batteries and wheel motors would remove so much weight that the performance on long journeys would skyrocket, and combined performance might well be just as good anyway. And the cost would be significantly less. And less to maintain too. I think a lot of the Prius appeal (to some) is that it is trendy.
|
|
Another advantage of the regenerative braking system is reduced brake and disk wear, especially for taxis where they get a hammering.
|
I think a lot of the Prius appeal (to some) is that it is trendy.
After all the technical ingenuity of the thing has a beguiling side. And running gently in town on a full battery it is absolutely silent, not just very quiet like many modern cars. Indeed that is what some people complain about, these things creeping up behind them when they are waddling about in the road without looking.
I'd like to try one although I don't want one, but I am told I shouldn't because I have a pacemaker. Apparently the Prius runs along generating sudden surges of magnetic flux, theoretically capable of making unwanted adjustments to that excellent device.
|
|
|
|
|
|
