Ooooh...nice article Pale. Looks like I'll be adding IGN to my SGII display and will be P&G from 65 mph down to 50-55 mph and trying to keep it at 14 IGN along the way...nice 65-80 mpg runs from those guys! I should note this will be not using neutral while doing it...I'm convinced 62+ mph in neutral is a hazard to the MG1 in the Prius engine...not a good idea.
Got solid documentation from this guy...
There is plenty of documentation, in particular at Graham's Toyota Prius (
Graham's Toyota Prius), Graham Davies paper.
In the Prius trans-axle, the fixed gearing means that the rotational speeds of the ICE, MG1 and MG2 are in constant relationship to each other, according to the following equation:
MG1 = 3.6 x ICE - 2.6 x MG2.
In addition, MG2, the main traction motor is related to the road speed of the car by the following equation:
MG2 = 59.1 x V (mph) ... where V is the road speed in MPH. (It varies slightly as the rolling radius varies with tire pressure)
So when the ICE is off (=0), MG1 = -2.6 x MG2.
Thus at 62 mph, MG2 = 59.1 x 62 = 3664.2 rpm.
So MG1 = -2.6 x 3664.2 = - 9527 rpm (rounding the fraction), which is close to its' published limit speed of 10,000 rpm.
Note too that it is also rotating backwards and acting as a generator.