MPG gain over G2

Patience.

It will take an entire year to gather that real-world data.

Those of us in the north (like me!) will likely experience the greatest benefit, due to the heating improvements.
.

 

2010 Prius with 15" rims will gain 3 City MPG and 4 Highway MPG over the Iconic Prius. This is with 10mm wider tires.

 

What are the heating improvements? Do you mean bigger engine = more heat, or did I miss something?

 

There is a heat exchanger on the exhaust system. It is used to heat the engine coolant.

Tom

 

There is a Chief Engineer's interview article on Japanese site.
Chief Engineer's interview

• 2010 Prius improves aerodynamics
• The reason of using 1.8L engine from 1.5L is for increasing fuel economy
• We see 10% rpm down on highway, then it is very meaningful data
• Especially at 100km/h(62mph) to 120km(75mph) area, we expect big mpg gain

Because of weight increase, I predict we'll see more EPA highway mpg increasing than city, such as +9% highway and +7% city.
Unnamed source says +10% at around 70mph.

Ken@Japan

 

That's a devastating blow for the hybrid antagonist and Two-Mode supporters, since both argued highway efficiency wasn't enough. This improvement will definitely be enjoyed.

Dang! The next 4-5 months is going to be a looooong delivery wait.
.

 

I agree.
Another Japanese magazine wrote "One of Toyota's targets is beating European diesels on highway mileage number".

Ken@Japan

 

highway numbers are especially important for press and bragging rights... so when some smart butt decides to drive Prius vs 5 series diesel on long highway journey, Prius will win this time . Those very superficial comparos are really silly, but not many people understand how silly they are.

RX450h also got considerably better highway numbers than before.

I think better heat retention will help the most in europe as it will help a lot during our short city rides where prius previously wouldnt be able to heat up before we arrived at destination.

 

Does the new engine have direct injection? One of my previous cars (MazdaSpeed6) had that. It can boost HP for the same size engine, or keep the same HP but improve fuel economy (such as on the regular non-turbo Mini Cooper)
Not sure if/how direct injection would work on a Atkinson modified cycle though. That would mean a fuel/air mixture would go upstream as the intake valve stays open for a while during the piston-up movement.

 

I know
What I mean is that in a direct injection engine, there is no F/A mixture upstream of the intake valve. For this reason it might be impossible/difficult to implement a direct injection system in an Atkinson engine

 

Very interesting and challenging! Diesel fuel has ~15% more energy than 87 Oct gasoline to begin with. It will be an incredible achievement!

I can't wait to see the stunt highway MPG comparison of the 2010 Prius with the Jetta TDI. Will the diesel supporters have the balls to attempt another stunt?

 

Most of the improvement is in the vehicle. There is no single part or subsystem that by itself accounts for all of the performance improvement.

Understand that 'city' and 'highway' performance are not 'zero sum.' You don't get one by robbing the other. So let us look at the NHW20 model rating:

• 46 MPG Combined
• 48 MPG city (Combined + 2 MPG)
• 45 MPG highway (Combined -1 MPG)

Now Toyota projects a combined MPG for the 2010 model:

• 50 MPG Combined
• ? MPG city
• ? MPG highway

So let's just assume that 'city' and 'highway' mileage differs by the same values as the NHW20:

• 50 MPG Combined
• 52 MPG city (Combined +2 MPG)
• 49 MPG highway (Combined -1 MPG)

We could use a linear relationship but those numbers should come very close to the same result.

I was going to ask why knowing the 'city' and 'highway' mileage on Sunday, January 25, allows making a decision that can not be executed until April at the earliest and more likely June or July. But upon reflection, I prefer answers found in math and physics.

Bob Wilson

 

Bob,

We know the numbers already. See the picture I took from the chief engineer's notebook.

2009 with 15" = 48 / 45 MPG
2010 with 15" = 51 / 49 MPG
2010 with 17" = 49 / 46 MPG

 

never saw those pics, thanks a lot... as those are run under perfect conditions, there are defintly some differences between modes - keep in mind that during test cycles, cars are driven so they optimize mpg (so they always accelerate at slowest rate possible).

i think someone wrote some of the eco/power numbers wrongly .

is that 3.785 for european tests or?

 

1 gallon = 3.785 liter

Ken@Japan

 

Also improving the MPG is improved electronic controller efficiency. I think 5% came from the electronics. Before they needed to be water cooled because with 10,000 watts moving through even a small inefficiency makes heat. Now the electronics are air cooled.