Is HSD a variable ratio transmission? - Page 3 - GreenHybrid

ken1784 · #21 (**permalink**) 06-30-2006, 01:09 PM

I'm second to Bob on this thread.
There was a discussion at PriusChat...
http://priuschat.com/index.php?showtopic=19543&st=120
I believe nbalthaser@Greenhybrid is same as nielb@PriusChat.

Quote:

Originally Posted by bwilson4web

But you raise an interesting question, how do we evaluate the ICE-to-wheel efficiency of other vehicles?

FYI...
Following is my collected data of NHW-20 Prius driving highway with CC set at 91km/h(actual was 85 km/h).

Code:

section km   mileage   alt change
  28km	 24.5km/L	 127m
  15km	 18.7km/L	 248m
  62km	 40.8km/L	-663m

Saw such various mileage results even on constant speed.
The reason was the altitude change on each sections.
If we use 0.106L/100m fuel to cover the potential energy, the table becomes as follows;

Code:

 section km  fuel used  fuel pot  fuel adj  mileage
 	28km 	 1.14L 	-0.13L    1.01L    27.8km/L
 	15km 	 0.80L 	-0.26L    0.54L    27.8km/L
 	62km 	 1.52L 	 0.70L    2.22L    27.9km/L

Now, we can see constant about 27.8km/L mileage number for a virtual flat road.
The 0.106L/100m means...
34.6MJ/L * 0.106L = 3.67MJ consumed.
The mgh = 1350kg * 9.8 * 100m / 1000000 = 1.32MJ potential energy.
The tank to wheel efficiency is (1.32/3.67)*100=36.1%

We have following data on another vehicle...
1300kg NHW-11 Prius consumes 0.125L/100m ... 29.5%
900kg Honda Insight MT5 consumes 0.0823L/100m ... 30.9%

Ken@Japan

bwilson4web · #22 (**permalink**) 06-30-2006, 02:35 PM

Quote:

Originally Posted by ken1784

I'm second to Bob on this thread.
There was a discussion at PriusChat...
http://priuschat.com/index.php?showtopic=19543&st=120
I believe nbalthaser@Greenhybrid is same as nielb@PriusChat.

FYI...
Following is my collected data of NHW-20 Prius driving highway with CC set at 91km/h(actual was 85 km/h).

Code:

section km   mileage   alt change
  28km	 24.5km/L	 127m
  15km	 18.7km/L	 248m
  62km	 40.8km/L	-663m

Saw such various mileage results even on constant speed.
The reason was the altitude change on each sections.
If we use 0.106L/100m fuel to cover the potential energy, the table becomes as follows;

Code:

 section km  fuel used  fuel pot  fuel adj  mileage
 	28km 	 1.14L 	-0.13L    1.01L    27.8km/L
 	15km 	 0.80L 	-0.26L    0.54L    27.8km/L
 	62km 	 1.52L 	 0.70L    2.22L    27.9km/L

Now, we can see constant about 27.8km/L mileage number for a virtual flat road.
The 0.106L/100m means...
34.6MJ/L * 0.106L = 3.67MJ consumed.
The mgh = 1350kg * 9.8 * 100m / 1000000 = 1.32MJ potential energy.
The tank to wheel efficiency is (1.32/3.67)*100=36.1%

We have following data on another vehicle...
1300kg NHW-11 Prius consumes 0.125L/100m ... 29.5%
900kg Honda Insight MT5 consumes 0.0823L/100m ... 30.9%

This is brilliant! I would never have thought to approach the problem this way! Very, very clever!

Please correct me if I'm wrong but what Ken is showing is how to use the altitude changes and fuel consumed to figure out the fuel-to-wheel efficiency. So let me explain the approach.

1) Take at least three benchmark measurements with altitude changes at a constant speed to measure the fuel consumption.
2) Solve the simultanious equations to find the fuel consumption per altitude change (100 m)
3) Based upon the energy per unit of fuel, calculate the chemical energy per (100 m) of altitude change.
4) Based upon the vehicle weight, calculate the potential energy per (100 m) of altitude change.
5) The ratio of the two is the vehicle tank-to-wheel efficiency.

For my fellow Marines, he is measuring how much grunt it takes to go up a hill versus how much it should take.

Bob Wilson

ken1784 · #23 (**permalink**) 07-02-2006, 01:15 AM

Hi Bob,

Thank you for your comments.

The data for NHW-11 Prius was a single experiment.
Please try to do your own experiment with your Prius if you have time.

Ken@Japan

khalamri · #24 (**permalink**) 02-27-2008, 03:35 PM

Hello,

I have a small question: where can i find this article?

"Development of New-Generation Hybrid System THS II - Drastic Improvement of Power Performance and Fuel Economy" 2004-01-0064<

Thanks a lot for helping me.

ken1784 · #25 (**permalink**) 02-29-2008, 06:42 AM

Google is your friend...
http://www.sae.org/technical/papers/2004-01-0064
It is not free though.

Ken@Japan