2010 Prius 2ZR-FXE engine efficiency map

[donee]

Hi All,

It was mentioned that 220 g/kWh is 35 % effienciency.

I looked up this:

Brake specific fuel consumption - Wikipedia, the free encyclopedia

Brake_specific_fuel_consumption

,

Where it says for regular gasoline:

Regular gasoline = 18917 BTU/lb = 0.0122225 KW·h/g

Or, in other words 81.816 g/KWh.

So, 81.816/220 = .372 or 37.2 % efficiency.

And for 230 g/KWh - 35.6 % effiency.

[FireEngineer]

Can anyone identify where this chart came from. It doesn't seem to mesh with the others shown.



Wayne

[ken1784]

Originally Posted by donee

Hi Ken,
Wow, 45 km/h is only 28 mph. Just would not be practical here without driving the car for an hour before hand.

The speed limit on his training road is 40km/h and 30km/h, and the road is pretty empty at any time.
Therefore, it is very practical training road for him.

Ken@Japan

[ken1784]

Originally Posted by FireEngineer

Can anyone identify where this chart came from. It doesn't seem to mesh with the others shown.

It came from Japanese sales staff manual made by Toyota.
I agree the 1NZ-FXE line is too high.

Ken@Japan

[pulse]

Originally Posted by bwilson4web

-

Hobbit has done early work on intake valve timing but I didn't realize the importance until I went to the Detroit auto show in January and in April read another paper (1.) on adjustable valves. In my minds eye, I suddenly realized where the intake valve closes relative to the piston stroke becomes another throttle mechanism ... without the pumping loss of a throttle plate!

Actually the term 'pumping loss' that is found in engine papers and discussions describes an increase in entropy when a gas passes through a constriction or orifice. It takes work to move the gas but that isn't the case if the intake valve closing on the compression stroke changes angle and goes from OPEN to CLOSE without having a constrictor, an orifice, like the throttle plate.

1. "Newly Developed Inline 4 AR Series SI Engine," Tsuchiya, Hosoi, Hoshi, Shimamura, Hagiwara, Ito, Arai, Toyota Motor Corporation, SAE 2009-01-10048.

Toyota ZR engine - Wikipedia, the free encyclopedia

Toyota_ZR_engine

Thanks Bob - that's very helpful - I don't have access to the papers you quoted, but I was reading the Wiki above and wondering why Toyota would not have included their new "valvematic" technology on the new Prius if it would reduce pumping losses. (my assumption based on the Wiki's assertion that "...The Toyota 2ZR-FXE is a 1.8 L (1798 cc)

Atkinson cycle" target="_blank">Atkinson cycle

Atkinson_cycle

variant of the 2ZR-...", and not the 2ZR-FAE).

I don't see how late Intake valve closing reduces pumping losses? Does the 2ZR-FXE actually have valvematic? Not that I'm planning an engine swap or anything, I'm curious about just how much tech Toyota crammed into the ICE.

[ken1784]

Originally Posted by pulse

Does the 2ZR-FXE actually have valvematic?

No.
Instead of that, the 2ZR-FXE has the EGR system to reduce O2 intake air, then it runs wide open throttle for reducing the pumping loss.
The result is 220g/kWh very efficient gasoline engine.

Ken@Japan