Found: New Japanese Method for Measuring Hybrid Power

What is new here? Toyota used this method from the beginning, this is only standardisation of what is already practice.

I must check, but currently under EU regulations, there is no combined power rating in COC document, there is ICE power and electric motor power. My insurance (on kW) is based on the motor that has more power and not on combined power. With the introduction of HEV power standardisation this could change.

 

MG2 power was never part of calculation for NET horsepower, it was always ICE power + battery power.

GEN3: Prius ICE 74 kW + Battery 26 kW = 100 kW

But the devil is in the details (ICE power with accessories, restricted real life battery power ...)

 

That would imply no similar FWD car could ever be faster over that period. My Mazda is 3.5 seconds to 40.

This is likely the best the power system can do given constrained MG1 RPMs and MG2 currents.

I seriously doubt that. I suspect the traction battery is at near maximum during a portion of the time, constrained by PE or MG2 current during the lower end of the run.

I think that's a data or data fit anomaly, and doesn't actually exist.

 

I think the source in the first post is describing 'maximum system power' and not the new method of 'net system power' as Toyota calls it.
Peak engine power and peak battery power are not usually occurring simultaneously (at the same time), and I think the new method finds the max value of the graph representing total power vs. time in some standard testing method the Japs decided on.

 

On a car with a boundless CVT, they should. On a car with a limited CVT, they still should over the range that isn't at one of the CVT bounds.

 

Well, the battery is not boundless...it is exhausted very quickly.

 

indeed, and thats why they optimize its usage, so it is always able to give similar output... unlike phev's or ev's that can give a lot more power over longer time, and it not as if journos measure anything anyway. Most annoying thing in past years for me was absolutely no information on PHEV sports cars like i8 and others where journalists absolutely do not mention that those cars will not be able to provide peak hp forever, especially when driven fast on the track for instance.... what about providing MPG and power numbers before and after stored energy is depleted? Nope. I feel this is one of the largest deceptions in automotive history and nobody cares or understands.

 

Let's assume the battery peak power is 32 kW, @ 200 V this is 160 A or about 45C for the Li-Ion battery (about 24C for the Ni battery). I don"t think the BMS will allow these rates for more than few seconds.

 

We're only talking about 10-15 seconds. That battery should manage 45C for that short time without much of a problem. I have batteries at home that will manage 70C for 30 seconds without cooling.

 

As far as I know Prius battery works at max 20C (26 kW), but in reality it newer goes this far but it stays in 20 kW region (15C)

 

The question is, IMO, for how long the BMS allows the battery to stay in its peak power.
If the battery delivers its peak power same time with ICE peak power (5200 rpm) why there is a need for a new method? What is wrong with the current method (ICE peak + Battery peak)?

 

Agree.
I don't know if it is battery assembly limiting or some other component of the CVT limiting (MG1, MG2, inverter etc.) but it seems that in an open throttle acceleration test the ICE power and the battery power curves are not maximized at the same time, so there is a need to find the peak of the combined power curve which is the 'system net power'.

 

i think limiting factor is same as always, battery capacity and the fact that it is not a PHEV... it all comes from that. They have to make it so you wont have significantly slower car if you go at WOT for 15s and/or that engine does not have to recharge batteries more than needed.

Then again, Toyota could make PHEV model a lot faster in "power" mode by letting it output 70hp for long period of time, but thats simply not how they roll.

 

So if we applied this testing to Gen.III, I wonder if the numbers would be lower. I remember seeing some Dyno's of the Gen.III reading around 115 HP even though the system is rated for 134 maximum. So I wonder how many kW of power the new Prius can provide and for how long compared to the Gen.III, and maybe the Gen.IV actually has more power despite what it's lower HP number due to the new rating system would lead you to believe.

I'd like to know the Gen.IV's HP rating on the old engine + battery scheme.

 

i don't think toyota ever mentioned quicker acceleration as a goal, did they?