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Would this work for a hybrid vehicle?
patrickl:
--- Quote from: danny_galaga on July 02, 2008, 06:40:23 am ---i mention all this because it turns out that the current generation has pretty much ignored the great ideas of the past when it comes to hybrids. apparently the toyota hybrids for instance only use the electric motor right at the start of takeoff, and at say 5kph its all petrol motor. almost pointless. instead of using a 150 hp motor, maybe they use a 140 hp motor :dunno
--- End quote ---
You're way off on the engine specs in the Prius. The Prius has a 1.5l 70hp engine. The electric motor adds another 30 or 40hp or so.
In your comparison with the 70s also remember that cars have doubled in weight. People expect a different level of comfort and safety from their cars and that makes them a lot heavier.
Also, the Prius gets energy from braking. This means it doesn't have to run the engine to charge the batteries. Charging the batteries by running the engine is actually quite inefficient, which is why Toyota tries to avoid that.
Ed_McCarron:
--- Quote from: danny_galaga on July 02, 2008, 06:40:23 am ---yep, in the realm of newtonian physics, of which all of which describe is a part, you can't get something for nothing.
--- End quote ---
Careful Danny, you're within spitting distance of PnR there...
Gourami: simple rule to tell what will work and what won't - if it sounds too good to be true, it probably is.
Hoagie_one:
http://en.wikipedia.org/wiki/Conservation_of_energy
RayB:
BMW M3 vs Toyota Prius:
[youtube]http://www.youtube.com/watch?v=wq9ilgw1plc[/youtube]
danny_galaga:
--- Quote from: patrickl on July 02, 2008, 02:13:32 pm ---
--- Quote from: danny_galaga on July 02, 2008, 06:40:23 am ---i mention all this because it turns out that the current generation has pretty much ignored the great ideas of the past when it comes to hybrids. apparently the toyota hybrids for instance only use the electric motor right at the start of takeoff, and at say 5kph its all petrol motor. almost pointless. instead of using a 150 hp motor, maybe they use a 140 hp motor :dunno
--- End quote ---
You're way off on the engine specs in the Prius. The Prius has a 1.5l 70hp engine. The electric motor adds another 30 or 40hp or so.
In your comparison with the 70s also remember that cars have doubled in weight. People expect a different level of comfort and safety from their cars and that makes them a lot heavier.
Also, the Prius gets energy from braking. This means it doesn't have to run the engine to charge the batteries. Charging the batteries by running the engine is actually quite inefficient, which is why Toyota tries to avoid that.
--- End quote ---
i was quoting very rough figures. im going to check it out now, but id be very surprised if the prius is both 1.5L AND 70HP. thats a very inefficient sounding motor.
regenerative braking is great. but pretty useless if you arent moving ;) if this is what the prius does (no engine generating electricity for the batteries) then its no wonder the electric motor only drives it up to 5km/h or so! i think someone else mentioned in another thread that the prius doesnt get much more milage than their diesel car (although im not for diesel cars).
charging the batteries via a petrol motor is actually quite efficient. this is because, yes there are some losses involved because of the conversion of one type of energy into another, BUT the net effect is a lot less petrol used (and thus much higher MPG) because the engine isnt always running. and when it is, it runs at a constant speed rather than accelerating and decelerating all the time.
just checked the toyota prius wiki. good god! youre right about that motor! i guess its a whole different ball game. those specs are more like light aircraft engines. which now i think about it makes sense since both the electric motors AND the engine in the prius are running when accelerating. the electric helps pull the revs of the petrol engine quickly, actually starting it, it seems to me. also from the toyota prius wiki:
"Auto Express magazine performed independent fuel efficiency tests, on public roads, on a number of hatchbacks, and in August 2007 published their list of the ten most efficient. The Prius achieved 10th place in the list, returning 41.5 mpg–imp (6.81 L/100 km / 34.6 mpg–U.S.). A Citroën C4 Coupé 1.6 HDi got 1st place with 49.6 mpg–imp (5.7 L/100 km / 41.3 mpg–U.S.).[41]"
and it also mentions the top gear episode that im guessing rayb has youtubed for us (im guessing because i have teh sux innernets and cant wait an hour or so to look at the clip!)
i dont know why you mentioned cars doubling in weight? my 70s model cars were/are about 1000 kg. the equivalent kind of car now is not 2000 kg!
anyway, gourami thanks for the thread. its got me thinking about hybrids a bit more (",)
also from toyota prius wiki:
"The engine is used both to propel the vehicle and to recharge the batteries. Because of the availability of extra power from the electric motors for rapid acceleration the engine is sized smaller than usual for increased fuel efficiency and lowered emissions with acceptable acceleration;"
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