Toyota to release 2 different Prius-es to US & Europe

[bob_ninja]

The 1.5L engine seems to lose efficiency above 2,600 rpm and really tanks above 4,100 rpm (NHW11 testing.)

The engine's top revolution rate has been increased from the 4,500 rpm in conventional engines to 5,000 rpm

Ahhh, I assumed max 8K RPM ... although red section starts around 7K RPM, at least in my conventional cars. So Prius has a smaller RPM range and 3K RPM is already more than half way to max. Now I see why a bigger ICE is needed. You are saying that already after 3K RPM efficiency has peaked whereas in my mind I always picture peak efficiency in the 4K-5K range.

I'll have to reconsider this .. looking forward to actual real data once it comes out.

Sorry Bob, post #24 is from another thread, here: Leaked document reveals Honda Insight mpg & CO2

Oh I missed this one.Thanks.

In fact thanks to all for the great info and patience. I am happy to learn about new developments and adjust my thinking accordingly.

[jprates]

Originally Posted by spwolf

you guys need to read about gas recirculation in new RX450h, where they managed to cut off warm up by 15 minutes in -5C

Indeed, thanks for the hint, I will search the net for more info!

Originally Posted by spwolf

Also, I am pretty sure that ECE tests do not test vehicle in cold conditions?

You would be wrong here. Since 2000 the test cycle has a cold start. Well, to be honest the first 10 seconds are idle time, not that it makes much of a diference. You can find hundreds of references to this on the internet.

[JSH]

Originally Posted by jprates

You would be wrong here. Since 2000 the test cycle has a cold start. Well, to be honest the first 10 seconds are idle time, not that it makes much of a diference. You can find hundreds of references to this on the internet.

I think the two of you are talking about different things.

I suspect spwolf is taking about ambient temperature. (Air temperature)
jprates is talking about engine temperature. (The engine is not warmed up to full operating temperature = cold start)

Here is a link to the entire ECE procedure: Emission Test Cycles: ECE 15 + EUDC / NEDC

Ambient temperature is not cold: 20C to 30 C (68F - 86F)
However the engine is not allowed to warm up to operating temperature before the test. (Operating temperature is ~ 190F or 88C)

[Patrick Wong]

Originally Posted by bwilson4web

Looking at the patents, the computer controlled, variable intake and exhaust valves should have both duration and phase control and eliminate the throttle plate while optimizing efficiency across a broader range of speeds and power settings...

Since Bob mentioned the Valvematic patents, here's a link for serious students to study prior to the Monday 2010 Prius announcement.
http://paultan.org/valvematic.htm

Elimination of the throttle plate would be a big improvement.

Regarding the discussion about 1.5 liter vs. 1.8 liter, its not necessarily a given that a new 1.8L engine has greater mass compared to the old 1.5L. We'll have to compare the specs of the two engines to see.

[spwolf]

Originally Posted by Patrick Wong

Since Bob mentioned the Valvematic patents, here's a link for serious students to study prior to the Monday 2010 Prius announcement.
http://paultan.org/valvematic.htm

Elimination of the throttle plate would be a big improvement.

Regarding the discussion about 1.5 liter vs. 1.8 liter, its not necessarily a given that a new 1.8L engine has greater mass compared to the old 1.5L. We'll have to compare the specs of the two engines to see.

thats true too - i dont think that new 1.8l ZR engine will be significantly heavier than old NZ engine... BUT, it will still be heavier than 1.5l NR that will be in Prius :-) (if that happens). Still, i dont think that we are talking about more than 10-15kg.

[bwilson4web]

Originally Posted by bob_ninja

Ahhh, I assumed max 8K RPM ... although red section starts around 7K RPM, at least in my conventional cars. So Prius has a smaller RPM range and 3K RPM is already more than half way to max. Now I see why a bigger ICE is needed. You are saying that already after 3K RPM efficiency has peaked whereas in my mind I always picture peak efficiency in the 4K-5K range.

I'll have to reconsider this .. looking forward to actual real data once it comes out.

Oh I missed this one.Thanks.

In fact thanks to all for the great info and patience. I am happy to learn about new developments and adjust my thinking accordingly.

No problem since many of us had to pass through the same learning experience. If you'll ignore the 'outlier' data below the zero line, you'll notice how the ICE shaft power begins to fall off around 2,600 rpm really falls off above 4,000 rpm. But in a traditional Otto engine, peak brake specific fuel efficiency occurs at a higher rpm:

Speculation on my part but I believe the variable valve timing and other engine controls in our current engines moves towards an Otto cycle to get a larger charge in and thus moves away from Atkinson cycle efficiencies. To get peak power out of the 1.5L engine, I suspect Toyota engineering had to sacrifice thermodynamic efficiency. My hope is the larger displacement will allow the new 1.8L engine to preserve thermodynamic efficiency across a broader power range.

I'd also like to see an electric water pump with elimination of the belt and coolant thermostat. If some of the exhaust gas can be used for engine block warm-up to eliminate the North American coolant thermos and use exhaust heat for cabin heating.

Bob Wilson

[Jared]

I am very happy that the new Prius will have a more powerful engine. I have always thought my 2005 Prius was underpowered off the line, and when I got a Camry the difference in power was striking. I like to get excellent mileage, but you have to like the way the car feels too. I hope the new Prius will have softer seats. My 1995 Tercel has more comfortable seats and this is not acceptable. I have also had issues with traction control. I could not climb a snowy hill a few weeks ago - the traction control just shuts off the power as soon as the wheels start slipping. Aside from these issues, I love my Prius and hope for a better one.

By the way, does the sun roof have any advantages or is it just for show?

[spwolf]

Originally Posted by Jared

I am very happy that the new Prius will have a more powerful engine. I have always thought my 2005 Prius was underpowered off the line, and when I got a Camry the difference in power was striking. I like to get excellent mileage, but you have to like the way the car feels too. I hope the new Prius will have softer seats. My 1995 Tercel has more comfortable seats and this is not acceptable. I have also had issues with traction control. I could not climb a snowy hill a few weeks ago - the traction control just shuts off the power as soon as the wheels start slipping. Aside from these issues, I love my Prius and hope for a better one.

By the way, does the sun roof have any advantages or is it just for show?

thing is that in Europe, Prius will cost same money as Avensis.... For it to have only smaller engine, it makes no sense, because it is in price range of more powerful vehicle.

If Prius was priced as Auris/Corolla, it would be different... but it is not (although i do expect cheaper base version, even significantly cheaper than before).

So I fully expect 1.8l version in Europe as well, even if optional. It would let Prius compete well with vehicles that are in its price class (Avensis, Passat, Mondeo, etc).

[jprates]

Originally Posted by spwolf

thing is that in Europe, Prius will cost same money as Avensis....

How do you know that?

Originally Posted by spwolf

So I fully expect 1.8l version in Europe as well, even if optional.

It's not optional, it's the only one you'll ever get.
Just like today, the future Prius will use the same ICE worldwide, I've got full confirmation from Toyota here.

I had already said it in this very same thread: Toyota to release 2 different Prius-es to US & Europe

[ggarb]

I would be perfectly happy with the larger engine, and more power, as long as the total fuel economy is also measurably better than my Gen 2. As long as it's better in every way, I won't be upset that it wasn't optimized just for fuel economy.

For the past few years I've driven from the Bay Area to Tucson over the holiday break. It's about 14 hours of total driving time, with two or three minor mountain passes. It's mostly Interstate highways, speed limit 70 in California, 75 in Arizona.

My current Prius is happy to zoom along with the bulk of the traffic at 70-80 mph, while giving me between 42-46 mpg. I focus on driving, not on maximizing my mileage - I don't pulse and glide or do any other hypermiling techniques. I'm not criticizing them, but I don't choose to do them.

There are a few places, like heading up the Grapevine into LA, where I reach the limits of what the current car can give me. I'd like to have a bit more power in reserve. I'd like larger battery capacity, so I can store more regenerated power on the long downhill sections. I would enjoy a slightly larger passenger compartment. And I really would like better seats, with more lumbar support, more adjustments. My dog is okay with the passenger seat, since I lay it flat and put her bed onto it, so she doesn't sit on the stock seat anyway.