Are the wheels on 2010 Prius alwaus driven by Electric Motor?

Good point. We don't want to confuse anyone. MG1 is locked by using a stationary field, not any sort of mechanical lock.

Another point to make is that MG1 standing still is not very common. It's only one possible point in the continuum from going fast in one direction to going fast in the other direction. MG1's speed is all over the map, depending on the desired virtual gear ratio. Starting from a dead stop, MG1 has to spin pretty fast to allow the ICE to run at a reasonable speed and to create the low virtual gearing needed at low speed.

Tom

 

The Prius does accelerate using the HV battery - at first. But if the demand is high OR the SOC is low, the ice will start shortly thereafter and provide juice via MG1.

I don't think it's possible to get max torque from MG2 using only the battery - I think you also need electrical power from MG1.

 

Correct. The HV battery isn't powerful enough to run MG2 at full power.

Tom

 

Max battery output is 27 kW, while MG2 max output is 60 kW: the difference needs to come from MG1, rated at max 42 kW.

So part of the ICE torque exert power to the wheels and another part to MG1, which power is electrically transferred to MG2 to add on ICE torque to the wheels. Power amount to each (MG2 and MG1) varies with rpm of the three planetary gears. Power = rpm x torque. So with MG2 at 0 rpm, coming from a full stop, all power goes to MG1, feeding MG2 a max of 42 kW and the HV battery contributing what it can (depends on SOC, temp, etc.). I guess the system has a preference for using MG1 power instead of battery power, to avoid having to run MG1 later to recharge the battery (inefficient).

(ref. http://priuschat.com/forums/gen-iii-2010-prius-main-forum/61868-battery-strength.html)and http://priuschat.com/forums/gen-iii-2010-prius-main-forum/59089-mg1-rating-2.html)

 

During battery charge mode at idle, the Prius hybrid control system commands MG2 to act as an electronic clutch while it commands the I.C. driving force to be transferred to MG1 which in turn is commanded to act as a generator to charge the battery.

During I.C. start mode at idle, the MG2 acts as an electronic clutch while MG1 acts as a starter.

During the I.C. start mode at idle, the vehicle can remain stationary because MG2 acts as an electronic clutch.

 

I don't think I would use the term "clutch". It would be better to say "electronic brake".

Tom

 

Tom, I agree with you.

But the term "electronic clutch" is a Toyota term from here:

greenpatentblog.com/__oneclick_uploads/2009/12/gardnercomplaint.pdf