Well, the engine is spun to 1,000 rpm before it's started (as opposed to 100rpm with an alternator on regular cars). Also, because of the CVT-like properties of the PSD, it seems it'll rev to about 3,000rpm immediately to provide power.
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2010 Prius Technology Package (Cdn)
OEM Cargo Mat, OEM All-Weather Mat, LED ext/int lights, 5000K HID, OEM Fogs, Euro Mudguards
Um, that dyno shows a 30% drivetrain loss. Anyone with a physics background knows hybrids are inherently inefficient, but 30%??? That's worse than I thought.
It looks like the 2 engine idea of the hybrid does nothing but compensate for it's own inefficiency. It's no wonder gas powered Euro's get the same mileage. I can't believe there are so many uneducated consumers buying into a completely useless technology like hybrids. It just shows the average person has no knowledge of science. We should be buying CNG, diesel, pure electric, and hydrogen cars instead.
Choosing fake environmental feel-good fantasies over real solutions FTL.
Last edited by fm.illuminatus; 06-23-2008 at 12:07 AM.
Science has not been a factor in car culture.People accept depreciation that does not make economic sense.Leasing every three years just creates demand for more new vehicles.
Environmentalism is quasi-religious not scientific.Religious people wear headscarves or crosses but that does not assure anything.When God is on the front door there is trouble out back.
Toxins are the new evil spirits so smoking is banned and carbon dioxide will lead to extinction.Purification from imaginary evils is the pursuit of religion.Religion is like ideology,mine is pure but yours is tainted.
One does not need to understand aerodynamics or navigation to sit in the back of the airplane.Religion has leaders and followers like hybrid owners.Owning a hybrid for ideological reasons is logical if your intent is to enforce belief.
Um, that dyno shows a 30% drivetrain loss. Anyone with a physics background knows hybrids are inherently inefficient, but 30%??? That's worse than I thought.
Drivetrain loss is one of the factors which determine overall system efficiency. Lots of people will consider real-life fuel efficiency (mpg) or CO2 emissions as the final criteria that matters.
The Atkinson-Miller cycle and the regenerative braking are the key to the Prius's efficiency. There aren't many vehicles on the market that implement those old, simple and yet effective technologies.
More importantly, you miscalculated the drivetrain loss. It's not 30%, it's 12-13%. The graphs show an average of peak 96HP, and the hybrid net system peak power rating is 110HP.
Quote:
Originally Posted by fm.illuminatus
We should be buying CNG, diesel, pure electric, and hydrogen cars instead.
Choosing fake environmental feel-good fantasies over real solutions FTL.
There are very few available cars on the market that obtain better fuel efficiency and lower emissions than the Prius. Although it's not the ideal solution, it's a much better solution that 99% of the available vehicles in North America.
I'd love to drive a diesel/hybrid that could run off biodesel made with organic waste (further reducing landfills) and lower our dependance on Middle East Oil.
Drivetrain loss is one of the factors which determine overall system efficiency. Lots of people will consider real-life fuel efficiency (mpg) or CO2 emissions as the final criteria that matters.
That's because people fundamentally misunderstand engineering. The significance of the 30% drive train loss number, is if you took a Prius's weight, speed, and drag CD, and applied it to pure gasoline car, the pure gasoline car would yield 10% to 15% better mileage than the Prius. The only reason the Prius is hailed as such an amazing car, is because no one has built a pure gasoline car (in the United States, at least) with a focus on pure fuel economy. The American consumer is apparently too uneducated to understand engineering (and the underlying physics), and in the absence of any equally fuel conscious pure gasoline car to compare against the Prius, isn't aware enough to realize that the Prius is in fact a step back.
On the other hand, the global (non-American) consumer doesn't have this myopic view, because they have access to more fuel efficient gas cars available around the world which we are not allowed to buy. All the Prius ends up being is a symbol of the ignorance of the American consumer; you should hear what the British think of it. The Prius is not a really a hot seller anywhere else in the world for good reason. And everyone else is more concerned about the environment than we are, if you believe the polls.
Quote:
Originally Posted by Stefx
The Atkinson-Miller cycle and the regenerative braking are the key to the Prius's efficiency. There aren't many vehicles on the market that implement those old, simple and yet effective technologies.
If the Atkinson-Miller cycle was such a forward thinking innovation, it wouldn't translate to such inefficiency. I suspect it sounds good on paper, but doesn't work in real life, just like perpetual motion machines.
Regenerative breaking is the only new technology that contributes to improving the Prius's efficiency. However, in a highway situation, it's almost useless. Around the city it's helpful, but the Prius still dips into the gas every time the driver pulls away from a stoplight, reducing the effect of brake recharge on mileage.
Quote:
Originally Posted by Stefx
There are very few available cars on the market that obtain better fuel efficiency and lower emissions than the Prius. Although it's not the ideal solution, it's a much better solution that 99% of the available vehicles in North America.
I'd love to drive a diesel/hybrid that could run off biodesel made with organic waste (further reducing landfills) and lower our dependence on Middle East Oil.
It is true that the American consumer has little to choose from in terms of getting good mileage. However, the Prius gets good gas mileage for every reason BUT the hybrid system (great drag cd, light weight materials, small gas engine). I'd rather not vote with my money for hybrid technology, which was ineffective from day one. It just encourages auto manufactures to try strapping hybrid systems on everything, including SUV's, which is absurd. Plus, I don't want to be bored to death when I drive.
The smartest thing we can do in the short term is what everyone else but China does, drill for oil in our own territory, then use it sparingly in the form of diesels and efficient gas cars. Somehow though, a sensible solution like that has been lost in the political noise and ultra-fanaticism surrounding saving the environment.
There are also other solutions to the gas problem. Honda makes a great new CNG car. Tesla is also developing a wicked electric roadster/coupe in cooperation with Lotus. Someone could also time the stoplights right, for once. That would save more gas than thousands of hybrids.
Last edited by fm.illuminatus; 06-24-2008 at 12:33 AM.
While your argument is valid, it falls short of addressing the real benefits of the Prius.
For example, I drive a Prius for work reasons in/for the City of Toronto. All trips are 90% city driving. Toronto City traffic is terrible just like any other major city. In fact I can Walk a city block faster than getting there in a car. But sometimes you need a vehicle to carry large items and other materials.
My argument is this; On a 1 hour drive in the city I am stopped more than 60% of the time. All this time there engine is COMPLETELY off. This means i'm cutting down my idling time to none.
So think of it this way, I can be siting in traffic all day long without emitting a single gram of pollutant. Doesn't that make sense? To achieve the same results in a gas car, you'd have to turn it off every-time you hit a light.
Gas powered cars had more than half a century to evolve, while the hybrid technology is just budding. Hydrogen powered/full electric cars are not viable, yet...Once we figure out how to supply hydrogen safely there will be no reason not to switch to Hydro-cars.
I dont know if you've driven the new Prius. It holds its own when it comes to performance, its in class of course. That electric motor/engine combination has so much torque when going up hills. (and its instant) On the hwy its not a slow poke and I pass semi's confidently.
In Europe they do not get nearly the amount of snow we see every winter here in Canada. I like to see a little 3 cylinder make it through a foot of snow everyday.
You can argue that most Prius purchases are because of the mee-too attitude, or pseudo environmentalism. And since you are coming from an "engineering" perspective, you can certainly appreciate the topics I've brought up.
Finally, if you dont want to be bored while driving take a look at the TCH. It is lots of fun to drive while still getting an average economy of 40+ MPG
OH: I forgot to say that the new Prius' have a electric AC compressor, so that it can run off the battery instead of the gas engine.
in the absence of any equally fuel conscious pure gasoline car to compare against the Prius
Agreed, in North America the Prius is one of the best choices among the available cars.
So your points:
1
There are better eco-friendly technologies than the Prius - I agree
2
Instead of the Prius you recommend the Tesla (a 100k car), hydrogen vehicles (not available yet) or European cars (not available in North America).
3
The Prius, although the best current eco-friendly choice in North America, isn't the best solution. I agree
4
You say that Prius purchasers are uneducated. I disagree
Point #4 : Prius purchasers are simply buying one of the best eco-friendly solutions available on the North American market. Hydrogen cars aren't available, all-electric are unaffordable (Tesla 100k USD) or too limited (Zenn).
If the Atkinson-Miller cycle was such a forward thinking innovation, it wouldn't translate to such inefficiency. I suspect it sounds good on paper, but doesn't work in real life, just like perpetual motion machines.
The Atkinson-Miller cycle works well in real life. You find it on most paralell-system hydrid propulsion solution. Your reference to inefficiency concerns the transmission, not the Atkinson-Miller combustion engine.
You don't find Atkinson-Miller cycle engines on non-hybrid for a simple reason. The Atkinson-Miller cycle engine gains in efficiency compared to an Otto cycle engine, however it lacks power/torque at low RPM, where an electric motor shines. Matching an Atkinson-Miller cycle engine with an electrical motor is a good match for city driving.
Quote:
Originally Posted by fm.illuminatus
Regenerative breaking is the only new technology that contributes to improving the Prius's efficiency. However, in a highway situation, it's almost useless. Around the city it's helpful, but the Prius still dips into the gas every time the driver pulls away from a stoplight, reducing the effect of brake recharge on mileage.
I agree with you that regenerative braking is a great way to improve a car's fuel efficiency in city driving. It goes without saying that regenerative braking was never designed to improve highway fuel efficiency.
For someone who mainly does highway mileage, he would be better off with a nice diesel reliable car.
Um, that dyno shows a 30% drivetrain loss. Anyone with a physics background knows hybrids are inherently inefficient, but 30%??? That's worse than I thought.
How do you get to 30% drivetrain loss?
The net max power of the hybrid propulsion system of the Prius is 110HP.
The five runs on the dyno's graph show an average max HP of 96.07.
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