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If you have a ScanGauge, you can monitor the MG torques and RPM while you drive, and power = torque * rpm. Also note that since the ICE can't send torque to the wheels unless it's acting against MG1, MG1 torque and ICE torque are synonymous.

In practice, MG2 torque is usually pretty low (less than +/-20 lb-ft) except when running at low speeds with the ICE off, or under high acceleration in the PWR range of the HSI. When you're cruising at highway speed in the ECO range with the ICE running, MG1 torque is very consistently in the 15-25 lb-ft range (in the vicinity of 50 lb-ft to the final drive) as the ICE is generating a relatively constant torque and varying RPM to match power needs. However, the car is trying to optimize total system efficiency, so in heretical mode at low power levels it will reduce MG1/ICE torque (and somewhat reduce ICE efficiency) in order to avoid a big MG2->MG1 power flow and the corresponding large electrical losses.

The ScanGauge is truly fascinating to watch in a Prius. At a stop while the ICE is warming up, you can see MG1 producing a torque as it's charging the battery, and MG2 producing a counter torque so that little if any torque is sent to the wheels.

 

Torque output is fairly straightforward but can't be graphed without knowing speed. look at a bsfc diagram for the engine and normal operation, and follow that line, it should give you ranges of engine torque at rpm. The power split is 72% output shaft/ 28% mg1. If mg1 is acting as a generator then it will produce power of rpm (mg1) x 0.28/5252 engine torque. Now here is the tricky part, the battery can source or sink power so that power net of what ever the battery does feeds to mg2 which adds its torque to the output shaft. The complicated thing is mg2's rpm is determined by the speed of the car, so power split is speed dependant. That ratio has changed with the various generations of cars.

Much easier to think of conceptually is an eCVT with boost. When you press on the accelerator the software calculates what the battery and engine should supply in terms of power. The engines power determines its rpm and the cars speed determines the output shafts rpm. MG1 will turn to provide that gear ratio between the engine and output shaft, creating a eCVT. If it turns foward it produces power, which is fed to mg2 to provide torque (more power is equivalant to a lower gear). If it turns backwards it is supplied power from mg2 and/or the battery to provide overdrive gearing. The gear ratio between the engine and output shaft is countroled by software which controls mg1 creating an electronic CVT.

 

Each pri gen has different rpm levels for heretical mode - and if you don't find enough detail in the above link - this one gives even more detail as to the various mode going's on;
Whats Going On As I Drive?
Good "in motion" graphics to help comprehension for us folks who are a tad slow at grasping such things.
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You know, I've read that page before, and thought I had a good grasp on what was going on. Apparently I didn't read it carefully enough. I'm going to now have to configure my EngineLink setup to show torque values for MG1, MG2 and the ICE to see what is going on now. I don't believe that EngineLink (or Torque) can show actual electrical draw/generation individually for MG1 and MG2, but I suppose it could be derived from the torque values.

I always thought "heretical" mode was when the gas engine was running, but the car was in reverse. Shows what I thought I knew...

 

I suspect it'll be another learning curve once the Prime hits the road.
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