Finally had some time to work on this power meter idea.
I removed the (cracked) front engine mount today and took a 5min drive to see what would happen...
Nothing
I'll try this for a while now to see if any vibrations or noises will develop over time. If successful, I believe it's possible to replace the two engine mounts with only one. My plan is to replace the front engine mount with a load cell equipped "copy" and at the same time remove the rear mount.
Now, regarding instrumentation, I read up a little bit on the MPGuino project and realized what I want: The MPGuino to measure speed, injector pulsewidth AND propulsion force and keep at least one hour of data sampled at 1Hz in memory for later off-loading to a PC. That would be some 10kB of 8bit samples, within reach of the 32kB of flash memory in the ATmega328P chip (?). This sampling would take place "behind" the normal functionality of the MPGuino.
Does anyone know if this is possible? How would the PC software make contact with the MPGuino and download the data over the USB?
I see great potential in this.
- More accurate Crr and CdA measurements.
- Engine efficiency could be calculated from fuel consumption AND mechanical power production.
- Throttle opening and engine temp are next in line to be measured
- For even more accuracy in the CdA measurements, one could put a load cell equipped "aero dummy" on a boom into clean air. This would be measuring the "0.5 x rho x windspeed^2" part of the equation and be used as a "dynamic pressure reference"
- More nerdy stuff...