Engine Cycle, P-V Graph (OTTO Cycle)

[Electrius007]

P-V graph should be plotted as pairs of (Xi/V, Yi/P) where i=0...360 two cycle engine.

X-Y Graph didn't have a buffer, data flow 100Hz (100rot/sec where 1 rot = 360 data points or Pi)

[GerdW]

Hi Electrius,

P-V graph should be plotted as pairs of (Xi/V, Yi/P) where i=0...360 two cycle engine.

That's clear to me and no problem once you collected the data.

X-Y Graph didn't have a buffer, data flow 100Hz (100rot/sec where 1 rot = 360 data points or Pi)

What's your problem in building your own buffer holding data for the last (or current) cycle?

Btw. with 100rev/s and 360 S/rev you should get data at 36000 S/s = 36kHz!

[Electrius007]

To build a buffer @100Hz holding 360points (P-V) synchronous with data flow is an issues... How?

Take in consideration cannot display @100Hz only 3-4Hz to change graph (will appear clods of points).

[GerdW]

Hi Electrius,

to measure with respect to crank angle you should use those encoder pulses as external sample clock. Then you just read 360 samples from your analog inputs to get the reading for one revolution!

Using an external sample clock will be the easiest solution to get the sample with respect to position instead of time - and IMHO the most accurate…

[Electrius007]

Thank you for suggestion. One revolution is 360points but on Graph volume has two variation Vmin - VMax - Vmin... also consider to save and retrieve data ... and many ...