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Author Topic: Feedback and suggestions for some spreadsheets  (Read 3351 times)
vjborelli
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« on: February 03, 2015, 12:42:59 PM »

So I've been trying to teach myself a few complex subjects (Physics, Fluid Dynamics, Thermodynamics), and I'm looking for some feedback on some initial spreadsheets I've been working on. The overall layout isn't going to be nice, as I just threw them together to get the numbers I was looking for. Later versions will be a bit more clean, or I may end up making a program in C if I get the time.

Mainly I'm looking to see if anyone can take a look and verify that my calculations are correct; if I'm missing any variables; if there are more accurate formulas to use.


First up is a spreadsheet I have on my tablet right now, "Acceleration and Power". I will post my Air Density and Fueling" when I get a chance to get back to my home computer.

Notes:
- Final wheel radius is based on an unloaded tire
- Gross vehicle mass is based on curb weight plus any additional weight in the vehicle
- I think the acceleration and power values, calculated in the section that I pasted a WOT log into, should only be accurate for the gear the log was created using (3rd gear for the log here).
- Torque (lb-ft) values, in the section that I pasted a WOT log into, are only converted from the Torque (nm) values in the same row of the current gear. In a later version, I will be using all the imperial values to correctly calculate these values.

Please post your questions, feedback, and/or corrections here instead of messages. This not only will help me, but it will help anyone that wishes to learn.

(Can't seem to post the file from my laptop correctly right now, hope this link works)
https://docs.google.com/file/d/0B-xI0Z5veB9ESXlqTWQ3eXJmeEU/edit?usp=docslist_api
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nyet
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« Reply #1 on: February 03, 2015, 12:46:25 PM »

Later versions will be a bit more clean, or I may end up making a program in C if I get the time.

Or send me ecuxplot patches Smiley
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vjborelli
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« Reply #2 on: February 03, 2015, 02:34:21 PM »

Or send me ecuxplot patches Smiley

I would be more than happy to contribute to the ECUxPlot program Smiley

I just want to make sure all my formulas are correct first.
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vjborelli
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« Reply #3 on: February 03, 2015, 03:04:39 PM »

Here are some of the main formulas used in the "Acceleration and Power" spreadsheet

- Velocity -
V(m/s) = V(kph) * 0.2777777778
V(kph) = V(mph) * 0.00044704
V(ft/s) = V(mph) * 1.4666666667
V(mph) = V(kph) * 0.6213711922

Where:
V = Velocity
m/sec = meters per second
ft/sec = feet per second
kph = kilometers per hour
mph = miles per hour


- Acceleration using: Velocity; Time -
A = ( V2 - V2 ) / ( T1 - T2 )

Where:
A = Acceleration ( m/s^2, ft/s^2 )
V1 = Starting velocity ( m/s^2, ft/s^2 )
V2 = Ending velocity ( m/s^2, ft/s^2 )
T1 = Starting time, relative to V1 ( seconds )
T2 = Ending time, relative to V2 ( seconds )


- Wheel torque, using: Mass, Wheel radius, Acceleration, Gear ratio
T = A / ( G / ( M * W ) )

Where:
T = Wheel torque ( nm, lb-ft )
A = Acceleration ( m/s^2, ft/s^2 )
G = Gear ratio ( Gear * Final drive )
M = Gross mass ( kilonewton, slug )
W = Wheel radius ( m, ft )

Note: Gross mass is vehicle curb weight plus any additional weight in the vehicle (e.g. Driver/passengers )
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