European "Prime" has different EV mode names

I don't think it does. EV Auto will turn on the ICE for full acceleration. If the system used dual motor before engaging the ICE, it would have to stop MG1, and then start it up in the other direction to start the ICE. This can be done quickly, but likely would still result with a delay in acceleration perceptive to the driver; like a shift point.

 

Quite clear, EV city - no dual motors. EU EV mode - dual motors engaged (not clear if always or at high power demands only).

 

It's clear comparing the MG2 rating which one has dual motor or not. It isn't clear if the modes just have different names, or are actually different.

I'm working on the presumption that NA EV Auto doesn't have dual motor operation. From the info released, Toyota applies the same logic to EV Auto that they did to the PiP's EV mode. The energy carried in the battery is far less than what can be carried in the gas tank. If an action starts using up that battery energy too quickly, whether heavy throttle, high speed, or heating for example, it is better to go into hybrid mode. Having two motors supplying power doesn't change the fact that heavy acceleration uses up energy quickly. So I think EV Auto doesn't use dual motors.

Now, there might be times when dual motors might be more efficient than MG2 alone. EV Auto could have dual motors if that is the case, but it means comparing MG2's power rating to the Mode's for determining if dual motors is possible is useless.

From Toyota UK's clarification that @GT4Prius posted, "EV mode – Primarily uses the electric motors, delivering a 68 kW electric drive for up to 39 miles. In certain conditions the engine will kick in and support where necessary, mainly in aggressive throttle use or speed greater than 83mph." That sounds just like NA's EV Mode. It has dual motor operation, and while many may not experience it, the manual does have a list of times in which the ICE could come on while EV Mode.

"EV-city mode – Provides a greater restriction on engine intervention and therefore uses the electric motors only, for up to 53 kW. This was designed to suit usage within stricter European city emission zones. The engine will only be activated if you kick down the throttle fully," doesn't sound like NA's EV Auto mode though. At least, from how it has been presented. I've taken it to be an EV mode that would allow more hybrid blending than the default EV mode. Perhaps I'm mistaken on that. If NA EV Auto works the same as EV City, that would explain posts by drivers not seeing ICE operation with EV Auto use.

Then there is this:
View attachment 125308
The same phrasing is used to describe the NA EV Auto and EU EV Modes, and different is used for the NA EV Mode and EV City. So it sounds like we have three different modes from this.

EU EV Mode and EV Auto are one and the same. The control algorithms could be close to what the PiP used with the improvements in the gen4 and Prime allowing much more EV only use. It has dual motor operation. Confusion about dual motor being EV Mode(NA) only arises from Toyota's mode nomenclature. I suspect that this is the default EV Mode as intended by Toyota.

NA EV Mode(EV-NA) is for satisfying the demand for the EV experience in the US. It stays entirely in EV operation up to the top EV speed or the battery can't take much more. Dual motor of course.

EV City is essentially the EV City that the European PiP had for ICE exclusion zones. No dual motor, but that isn't needed on the streets that made this mode a necessity for the market. The lower EV power output means lower acceleration and top EV speed, but again, that shouldn't be an issue in a city heart, and it maximizes the EV range. I don't know if the PiP EV City had ICE on with a floored accelerator, but it makes sense to have in case of emergencies.

 

??
EU EV mode uses dual motors up to 68kW. We do not know about EV auto. I suspect (like you) it doesn't.

 

That's what I thought until we saw that clarification Toyota UK using the exact same phrases to describe EV Auto and EU EV Mode. EV-EU has to have dual motor based upon its power output. So EV Auto could too at this point. Has anyone seen the power specification for EV Auto? My previous suspicions could have been in error based upon the lack of info.

Also, if the original Prime design did use a smaller battery pack, the default EV mode being closer to what the PiP had would make sense.

 

The fact is that for EV auto we do not know because they did not tell us. I still believe it is using MG2 only up to 53kW, makes sense to me for 'best of both sources' and more protection of battery (using up to 53/68 of its capability) and differentiation from NA EV mode.

 

I had agreed up until that clarification from Toyota UK describing EV-EU and EV Auto with exactly the same wording. Can't rule out it simply being a case of lazy copy and pasting, or that they copy and pasted the wrong section. If that is wrong, then the stated EV mode power ratings could be wrong?

"The engine will not start regardless of throttle opening angle," is enough differentiation to satisfy the typical PHEV buyer here looking to minimize ICE use.

 

It shouldn't create a delay over single motor propulsion. In both cases, for a given vehicle speed MG1 spins at the same speed (same goes to MG2), only in dual motors drive it is doing work while in single motor drive it spins freely. All it takes (in both cases) is to slow it down causing the ICE to spin forward ready for firing.

Maybe @Prius Team can chime in and tell us the max EV power in EV auto and is it dual motors drive or not?

 

Finally took a look at the PSD diagrams.
Graham's Toyota Prius
It might still result to a delay sensation to perceptive drivers if ICE start up happens under heavy, dual motor operation. The force input of MG1 to acceleration has to stop for the ICE to start and then take over.

I knew there something else I meant to add in the last post.

 

I don't think so.
Think of a regular (induction) motor: once you stop stator winding excitation (shut-off power), the motor instantly looses its torque to free spinning, from here on it is the same as single motor propulsion.
We have not heard from Prime owners of any delay (when switching from EV mode to HV mode).

 

Yes, it loses its torque, which means a car in dual motor operation loses that power to the wheels.
Starting the ICE is going to be as mechanically seemless as it is in the Prius, but it isn't a truly instant operation. If the ICE does need to start while dual motor operation is providing more power than MG2 could alone, there is going to be a dip in power going to the wheels as MG1 stops helping and the ICE starts.

I can entertain that dip in power output could be only detected by a perceptive driver, and perhaps only under circumstances. A detectable sensation would be along the lines of what could be felt when there is a fraction of a second delay between regen braking stoped and friction braking starts that sometimes happens. A pause in the acceleration or deceleration.

As for no reports on such a pause happening, I suspect most Prius drivers don't drive their car hard enough for the ICE to start while in dual motor acceleration. Without knowing if dual motor is available in EV Auto or not for certain, testing would be pointless at this time. The system is monitoring battery temp and SOC. So in EV-NA, the decision to fire up the ICE is made before going into dual motor operation, if it was deemed dual motor would be unsafe for the battery.

 

You are putting your thoughts as facts, how do you know this? Why would it be unsafe for the battery? What in your opinion is happening when exceeding 84 mph?

 

I do not see how MG1 dropping out of dual motor operation to start the ICE can be definitely seemless.

Wasn't saying sual motor was unsafe for the battery. There are conditions in which the system will switch to hybrid to protect the battery. One of those is when the battery temp is too high. Dual motor draws more energy from the pack; this generates more heat. If the pack is approaching the too hot point when the driver calls for heavy acceleration, it could turn on the ICE instead of dual motor. Low SOC is a similar case in which the system can decide to use ICE instead of dual motor.

In EV-NA, I believe the system can be 'smart' enough to predict when a high torques demand could result in needing the ICE. At those times, it doesn't bother with dual motor at all, and goes straight to ICE, so any dual motor to ICE issue doesn't arise.

Depends on what the car was doing before exceeding 84mph. Cruising wouldn't require dual motor operation, and any calls for heavy acceleration at those speeds will start the ICE. Starting the acceleration at a lower speed will have dual motor. When 84mph is reached while still accelerating, the hesitation or lag I think might occur when switching from dual motor to ICE will occur.

 

These are a collection of presumptions with no real backup source of any kind.
To conclude, here is what we know:
EV mode (NA or EU) engages dual motors drive, we do not know if MG1 always join or only at higher power demand.
Transition from dual motors EV mode to HV mode is seamless as reported by owners, no felt or detected delay (if a "delay" cannot be detected then...there is no delay).
EV city mode does not use dual motors drive.
We do not know if EV auto uses dual motors or not. It makes sense to me it doesn't.

 

How do the owners reporting know they were actually in dual motor operation before switching to hybrid?

Toyota UK's description of EV-EU and EV Auto is exactly the same. Without further info, it is a safe assumption that they are the same mode. So EV Auto will have dual motor also.

 

I don't have any info to share on that right now...but there is a white paper coming out soon which should answer most of these questions. Stay tuned.

 

My new Prius PHV arrived at the dealer and I can collect it tomorrow (Thursday)

 

When have you ordered it?
Here in Germany, it will take a few more weeks for me ...