I’ve had my 2010 for 9 months. Love it. I have a 2 questions regarding the electric motor. I see that: The gas engine is rated at 98 horsepower. The electric motor is rated at 80 horsepower. Total net horsepower is rated at 134. 1. Anyone care to fill in the details, in plane language for common folk like myself if possible, on how the net horsepower is calculated? I imagine there must be a complex equation to describe the contribution of electic and gas motors to produce total horsepower. 2. Though I see that the electric motor in the current model is rated at 80hp, and that in 2004-09 models it was rated at 67hp (according to Wikipedia), I’ve read in other reports that the electric motor in the 2010 Prius is smaller than in previous year models. Is that true? Is it physically smaller but more powerful? Is the horsepower output for electric motors in the 2010 models actually more than in previous year models?
The gas engine is rated at 98 horsepower. The HV battery is rated at 36 horsepower. Total net horsepower is rated at 134 horsepower. There is a generator that steals gas engine horsepower and send it to the 80 hp traction motor. That's why you need to sum the power from the power sources.
Put in different words, the HV battery is not powerful enough to drive MG2 at full power. At full power, part of the power for MG2 comes from the engine through MG1. MG1 is used as a generator which is driven by the engine. The electricity from MG1 powers MG2. MG2 in the 2010 is physically smaller than MG2 in the Gen II Prius. It also has lower torque. However, MG2 in the 2010 is geared so that it can spin faster, which is how it develops more power. MG2 in the Gen II is direct drive. Tom
For parallel hybrids, you can pretty much add the power from the gas engine and the electric motor to get the combined horsepower (assuming both engines peak at the same RPM). For series hybrids like the Volt, you can't add 71hp gas engine to the 149hp electric motor. That's because all the power from the gas engine goes to the generator which in turn power the 149hp electric motor. Prius is a split hybrid. It is geared to be 72% parallel and 28% series. The power from gas engine is split into two paths. The actual ratio of the power between both paths are controlled by the generator. The faster the generator spin, more power goes into the series path (and less into the parallel path). All of this appears to be complex but this was done with a simple PSD.
