Hi,
Yesterday I was doing more testing by recording my normal, morning commute route. Most of the data looks noisy as the Prius rapidly passes power between the ICE, MG1, MG2, and traction battery. But there is one segment where I got up to 55 mph (indicted) on a fairly flat section:
During this segment, the car actually achieved something that looked like a steady-state.
In this case, MG2 is working as a generator and passing power to MG1 which is working against the ICE to get it to run slower. That power then takes the mechanical path back towards MG2. So I took the data and calculated electrical path efficiency, MG1/MG2:
- ~70% - raw, not counting the vehicle overhead, ~500W, 44-78%
- ~82% - adding the vehicle overhead, ~500W, as an electrical path load with a range from 65-94%.
One lesson learned is the car has to be on a fairly flat section, otherwise altitude changes add and subtract to the load and makes steady-state measurements unusable. I am waiting on a GPS receiver but this may not be the best way to measure the small altitude changes that trigger rapid state changes in the Prius. So I may have to add vertical acceleration data to get an accurate, altitude change metric.
You'll also notice the ratio of power taking the electrical versus mechanical path changed substantially. It looks like the electrical path is favored as the engine power decreases. MG1 driving against the ICE is making it turn slower and like over-drive, into a potentially more efficient point on the operating line.
Bob Wilson