Quote:
Originally Posted by bwilson4web
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Also today, I reinstalled the Graham miniscanner and programmed it to record: - MG1 torque - that is 28% of the ICE torque and used to calculate energy flow
- MG2 torque - used to calculate MG2 energy flow
- ICE MAF flow - used to calculate fuel flow to calculate BSFC in operation and indicated and true MPG
- MG1 rpm - used to calculate MG1 power
- MG2 rpm - used to calculate MG2 power and in combination with MG1 rpm, the ICE rpm and power
- traction battery current - used to calculate traction battery energy flow
- parallel GPS tracking - recording true velocity and altitude, total mechanical energy
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I was thinking about this and decided to modify the test configuration:
- MG1 torque - is 28% of the ICE torque
- MG2 torque - energy flow via electrical paths from MG1 and traction battery
- MG1 rpm - used for MG1 power
- MG2 rpm - gives indicated speed and with MG1 rpm, gives ICE rpm
- traction battery volt - provides part of power measure
- traction battery current - with voltage, provides exact energy flow
- GPS - provides true velocity and altitude, the kinetic energy state
This drops the ICE fuel consumption for a more accurate traction battery power measurement. In the past, I've used the rated traction battery voltage for energy flow which was close enough but not exact. The new data will be as accurate as possible.
With this new setup, I'll be able to record and calculate:
- ICE power
- MG1 power
- MG2 power
- traction battery power
- vehicle kinetic energy
- vehicle potential energy
I just don't have enough fields to include fuel-flow but the operational BSFC can be done in a separate study.
I can replace the traction battery metrics with ICE metrics to remap the BSFC 'in operation.' This will also improve the accuracy of my mph vs MPG charts based upon an NHW11 with 138,000 miles. In particular, using GPS true velocity will be a great improvement as past measurements used just the indicated mph.
So I'll return to the lab, the experimental method, and measure with more accuracy what is going on in the Prius drive-train. Found my serial cable so should start data collecting early in the morning to get the lowest possible temperature. Will also add a short post-test set to measure traction battery electrical consumption with engine off and engine on. We'll average these short tests and take them out of the energy flow.
Bob Wilson