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Print 20 comment(s) - last by phryguy.. on Aug 11 at 4:07 AM

Toyota plans to sell 1 million hybrids per year this decade

The first mass production hybrid vehicle, the Prius, came from Toyota in the late 1990s. The Prius was soon joined by several other hybrid vehicles in the Japanese market including larger SUVs and vehicles aimed at commercial use. Today, Toyota offers hybrid vehicles from its luxury brand Lexus in the U.S. along with the Prius, Camry Hybrid, and Highlander Hybrid.

Toyota Motor Company (TMC) has announced that in Japan the sales of hybrid vehicles have topped the million unit mark. The Prius was also the best selling vehicle in Japan in 2009.

Globally, Toyota has sold over 2.68 million hybrid vehicles as of July 31, 2010. The company currently sells eight hybrid vehicles outside Japan with overseas sales for TMC at 1.68 million units. According to Toyota, its hybrid vehicles have resulted in some significant savings in greenhouse gas emissions. TMC figures that since 1997, its hybrids have resulted in four million less tons of CO2 emissions in Japan alone and 15 million fewer tons of CO2 produced globally.

Toyota has bigger plans still for its hybrid vehicle sales. The company plans to sell a million hybrid vehicles per year during this decade and add hybrid models to every vehicle in its line as early as 2020. Toyota's iconic Prius hybrid was launched in 1997. More recently, Toyota and electric vehicle maker Tesla have worked together on a new plant and the development of hybrid and full-electric vehicles.

There were also reports in May that a minivan using Prius hybrid technology would be coming next spring.



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How does a Prius save petrol?
By yxalitis on 8/9/2010 8:27:35 PM , Rating: 2
I have a question,
How on Earth can a hybrid save petrol?

The Laws of Thermodynamics tell us that every system suffers a loss, so whenever I use the electric engine, a certain amount of power is drawn from the batteries. However, whatever amount is drawn out, MORE must be used to recharge it (or else we would have an infinite power generator!).
The source of this recharge power, is the engine.
How is this more efficient then just using the engine to directly power the drive shaft. I suffer a loss in the overall system as I have to lose energy recharging a battery
AND I have to lug around an extra engine, and a lot of heavy batteries.
Now I know SOME energy is derived from regenerative braking, but once again we hit the laws of thermodynamics, whatever energy is spent accelerating the car will be much greater then that recovered when braking. From my research, regenerative braking is about 5% efficient, so that is certainly not going to make up the difference!

Over the life of the car, I have to use more power to recharge that battery, then work I get from it, period, full stop, no question.

So how come the entire world thinks the Prius et al use less petrol?
I just don't see how a car carrying hundreds of kilos of extra mass, and losing energy recharging a battery (remember, this is a closed system) is more efficient!
My guess, is that all the trial runs measure petrol consumption over a set course, but do NOT take account of the fact that at the end of the test run, the batteries are not in fact fully charged.
If I ran a FULLY electric engine over the same course, I would achieve ZERO petrol consumption, but in that case, of course, everyone would nod sagely, and state "Yes, but we now have to recharge those batteries"

Am I wrong, is there something I'm, missing here? Have I misunderstood




By khadafito on 8/9/2010 10:22:38 PM , Rating: 2
Four ways the Prius saves gas:
1) It is incredibly aerodynamic. It has one of the lowest drag coefficients of any mass-produced car (almost the same coefficient as the sportsy-lookin Telsa Roadster). This is obviously not related to being a hybrid, but it helps a lot.
2) The car has regenerative breaking. When you break, the electric motor becomes a generator that converts part of the kinetic energy into electricity that charges the battery. Then you use that recovered energy when the battery discharges by running the electric motor, which means less gas consumption. In a regular car, every time you break you waste all the kinetic energy.
3) When the car stops, the gas engine stops. In stop and go traffic you are only consuming gas when the car is moving. A regular car would be consuming gas all the time, including on an idling engine by just sitting still at a red light or on a traffic jam. When the Prius starts moving again, if you don't push the throttle too much, the car will move on purely electric power until you hit a certain speed (using, in part, the power stored in the battery from the regenerative breaking). Then the gas engine comes on.
4) A very sophisticated system of gears connecting two electric motors and the gas engine (and controlled by a computer) keeps the RPMs of the gas engine at it's most efficient spot (where it consumes the least gas) for a wide range of car speeds. Essentially, the computer is constantly adjusting the fraction of power delivered by the gas engine to keep gas consumption to a minimum. In a regular car, most of the time the gas engine is running at RPM levels where it's highly inefficient.

By the way, when you are comparing gas and hybrid or electric cars, keep in mind that the internal combustion engine, especially a regular gas one (Otto cycle), is horribly inefficient (Diesel cycle is better). In any regular car, at most 25 to 30% of the energy in the gasoline actually gets converted into useful motion of the car. The rest is wasted as heat. An electric motor + battery power train is way more efficient than this, but the whole analysis would get too long for this post.


RE: How does a Prius save petrol?
By mmcdonalataocdotgov on 8/10/2010 11:32:12 AM , Rating: 2
I just wanted to add that in a regular gas only car, energy is lost to heat when the car brakes. It is gone. In a hybrid vehicle, that lost energy is turned into electric energy. That is where the hybrid gets the battery power (predominantly.) The only time it takes energy from the gas motor is when the battery gets very low, or when the gas motor is running anyway but there is no load on it (over 45 mph).

The upshot is that I get 50+ mpg in my hybrid where I would get about 30 in a regular ICE car of the same dimensions.

It is not tricky thermodynamics. The hybrid just recaptures energy that the gas engine was p*ssing away anyway. An elegant solution.


RE: How does a Prius save petrol?
By phryguy on 8/11/2010 4:07:26 AM , Rating: 2
The other replies covered it pretty well.

The person asking should also see these for reference:
http://www.consumerreports.org/cro/cars/new-cars/b...
http://www.consumerreports.org/cro/cars/new-cars/b...
http://www.consumerreports.org/cro/cars/new-cars/b...

These are in smaller US gallons in Consumer Reports testing and are not from our EPA test nor the are they comparable to that of European test driving cycles.

44 (miles per US gallon) = 52.8418186 miles per Imperial gallon
32 (miles per US gallon) = 38.4304135 miles per Imperial gallon
55 (miles per US gallon) = 66.0522732 miles per Imperial gallon
53 (miles per US gallon) = 63.6503724 miles per Imperial gallon

There are also not "hundreds of kilos of extra mass". The HV battery in the Prius only weighs 53.3 kg. See http://www.myprius.co.za/technical.htm.

My 06 Prius is only 2890 lbs. which is actually fairly light for car classified by the EPA as a medium sized car. Most non-hybrid 4-banger family sedans off that era weigh 3000+ lbs.

5% efficiency of regenerative braking sounds WAY off. Where is 95% of the energy lost? That makes no sense. Even internal combustion engines don't have such poor efficiency. Also, one might want to look at http://www.fueleconomy.gov/feg/atv.shtml.


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