[quote=PineywoodsPete;156940]
Quote:
Originally Posted by Don R
Unless I am very mistaken, MG1's AC output is connected electrically only to the traction battery through the inverter, not directly to MG2&R also. If you have different info, I'd appreciate a reference!
I don't believe you will get - in a steady state - more than 45KW electrical power however it is split between the three (or two) motors, though brief spikes could exceed that. If more sustained power was actually available on maximum demand, why would the total 268 HP spec be the same for the two versions?
ICE generated electrical energy is very inefficient, on the order of only 20% of input energy (ICE thermodynamic efficiency of 30% or less, times mechanical to electrical generator efficiency of about 70%) as I recall. So using MG1 generated power under max power situations going forward would be grossly inefficient, actually subtracting from performance due to the mechanical>electrical> mechanical energy conversion losses.
Pete
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Please recheck your source. See the diagrams below from Toyota. MG1 and MGR can receive power directly from MG1 through the inverter while completely bypassing the battery.
The thermal to mechanical efficiency of an engine is typically less than 30% but all gasoline engine powered vehicles suffer from this loss so this isn't considered in the hybrid/non-hybrid efficiency comparisons.
Hybrid motor/generator mechanical/electrical conversion efficiency is much better than 70%.
Study the Toyota power split device. The engine, MG1 and MG2 and the front wheels are all mechanically connected by gears in a 4-way planetary gear set.
If any input/output to a planetary gear set is left open (freewheeling), no power can be transmitted between the other input/outputs.
In order for the engine to be able to turn the wheels, MG1 must be able to apply an engine-opposing force to the gear set which in turn generates electricity which in turn is sent to MG2 which in turn contributes positive motive force to the gear set. If MG2 could only supply 45KW of power, the engine could easily overpower MG2 and spin it backward in a partial freewheel mode preventing much power from being sent to the front wheels from the engine.
The total power sent to the front wheels equals sum total of
1) the engine power
2) less the power used by MG1 to generate electricity
3) plus the power from MG2 supplied electrically by MG1
4) plus the power from MG2 supplied by the battery
5) less the power from MG1 sent to charge the battery
6) less conversion efficiency and friction losses.
