Prius Prime hit piece on electrek.co

I refer you to pp 87 of the Owner's Manual:

■Gasoline engine operation in EV/EV auto mode
Even if there is a sufficient amount of electricity remaining in the hybrid battery
(traction battery) and EV driving range (→P. 199, 215, 222, 239) is being
displayed on the multi-information display etc., EV driving (driving using only
the electric motor) may be canceled and both gasoline engine and electric
motor are used depending on the situation (EV driving will be returned to
automatically after EV driving becomes possible again).
EV driving may be canceled automatically in the following circumstances:
●When vehicle speed is more than approximately 84 mph (135 km/h).
●When power is needed temporarily, for example when the accelerator pedal
is depressed firmly or when accelerating suddenly.*
●When the temperature of the hybrid system is high.
The vehicle has been left in the sun, driven on a hill, driven at high speeds,
etc.
●When the temperature of the hybrid system is low.
●When the heater is switched on when the outside temperature is below
about 14°F (-10°C).
●When the windshield defogger switch is pressed. (→P. 491, 501)
●When the system determines that the gasoline engine needs to be started.
The gasoline engine may also operate in circumstances other than those
listed above, depending on conditions.
*: When traveling in the EV auto mode only​

Accelerating up a hill is what triggered the engine coming on. There may have been other instances.

Bob Wilson

 

No, Bob...read the asterisk.

 

And just above the asterisk, "The gasoline engine may also operate in circumstances other than those listed above, depending on conditions." Granted this reads like a "Catch-22" clause but it highlights that the Prime is primarily an efficient hybrid car that has an EV capability. It is not like our BMW i3-REx that is primarily an EV car with a modest hybrid mode whose gasoline performance is more like a Volt.

It is common to find people have different requirements and it was dynamic cruise control and collision avoidance that once experienced with the BMW i3-REx led to replacing our Gen-3 with the Prime (Gen-5). In contrast, the Volt-2 as seen at our local Chevy dealer did not have dynamic cruise control, an extra cost option, and its highway MPG is distinctly worse than the Prime. So what could Chevy do to fix it?

• Put the Cruze diesel in the Volt-3 (since they can't make an efficient gas engine)
  
• Fix the lock-up in their automatic transmission (or put the EV motor in the manual transmission)
  
• Make the Chevy 'adaptive cruise control' and collision avoidance standard

Bob Wilson

 

My point is, the Prime is capable of operating in Ev mode with the pedal on the floor. It should only come out of Ev mode in edge-cases such as the timer, battery temperature issues, need for defrost or heat when below 14F, or when sufficient power isn't available at the very end of the charge. The pedal depression (i.e. accelerating on a hill) is in Ev auto mode, not Ev mode. The reviewer was in Ev mode.

I strongly suspect his test car had some sort of defect, and Toyota confirmed that.

Try it with your own car. You should be able to do a 0-84mph run (in a legal spot) all in Ev, and all with the pedal on the floor, hill or no.

 

It will have to wait until I finish my "EV Auto" test. So far, the car has turned on the engine under heavier loads but the trip meter is pegged at 199.9 MPG. I remember doing a hill climb test in EV but not trying to max it out. I did a maxed HV mode hill climb and it was nice. The problem is reaching the base of the hill is about 8-10 miles away. Also, I could not tell from the video what his cabin setting were.

Bob Wilson

 

does the asterisk matter when the first line says ev/ev auto?

 

Forgive my "newbieness"... but is there any reason to pick apart the minutia of EV operations?
Especially once they say "depending" it kind of gives them carte blanche.

 

I think that adding a couple small corrections to their documentation would have covered these cases:
When power draw from or power input to the system is high and sustained, the ICE may turn on to maintain battery health. (Such as climbing a steep incline while accelerating or descending a steep incline while using regenerative braking).

It is even possible that this is a known item that should have been in the documentation but when translating from Japanese to English the specification that was left out. You can find a lot of places in the documentation where the translations are just off. That said comparing a Volt to a Prime is a little silly because they are fundamentally different systems with different drivers. The Volt is an EV car with a range extender. It has a much larger extender than say the i3 does but that is because Chevy wasn't interested in the EV credits of doing what the i3 did which was to keep the EV range longer than the gas range. The original Volt very seldom powered the wheels from the engine, true that has changed in the second gen, but the main system is still the same, they retrofitted a Hybrid system into an EV versus an EV system into a Hybrid. So they are better at EV mode and the Prime is better at HV mode. Who is surprised?

 

Here is what I found:

• car heavily accelerates to 44 mph
• is in ECO mode
• line indicates "EV mode"
• 57F
• 5.8 mi @199.9 suggests has been in EV
• traction battery is low

• Owner's manual page describing EV mode "may be canceled and both gasoline engine and electric motor are used."

• Red circle is the area of interest:
  • 400 ft isobar to 450 ft isobar
• Blue "X" is where the accelerator was pushed heavily
• Fuschia line direction of travel

Bob Wilson

 

There's a long history of purists stirring the pot.

"Better" doesn't quite fit when you look at it in terms of electric efficiency. Prime earns a higher KWH/MILE rating.

 

Somehow I knew that statement was going to haunt me when someone pointed out the 133MPGe rating that the Prime got. The better in this case isn't about efficiency but maintaining EV only operation. The Volt is better at maintaining EV only operation, it isn't more efficient in EV mode. Part of the reason it likely isn't more efficient is because of the extra fringe cases where the Toyota abandons its EV only mode.

 

My daily drive to work is a 700 foot vertical climb, including one spot where I have to accelerate from 0 to 40 up a 12% grade and one where I have to accelerate from 0 to 50 up a 7% grade. This car should be able to do that all in Ev under all but the most extreme conditions. We'll see when I get it.

 

I have to get some stick time in a V2 and a Prime, but the Googles and Fanboyz seem to indicate that the Volt has a more robust EV mode.
Volt fanboys seem to like this feature, and they also REALLY like the regen-on-demand paddles.

Primers like to point out that the HSI is a more efficient (and integrated) platform, and that the vehicle now has an adult-sized 600+ mile range, which THEIR fanboys seem to like


meh.

From the outside looking in, it's a Coke-Pepsi argument.

 

people who's engine comes on when they don't think it should are disappointed. that's to be expected. picking apart minutia is what we do here, it's not 'stirring the pot'.
if toyota laid it out more succinctly, this wouldn't happen. everyone has different experiences, we went through the same thing 5 years ago with the pip, and there was never a conclusion.
toyota has hurt themselves by making statement's about the prime being a pure ev compared to the pip, so, cause for discussion and experimentation.
i'm sure if lee jay's prime doesn't go up a 700' hill at 84 mph without the ice coming on, we'll hear about it.

 

The zones are: 25, 35, 25, 40, 35, 50, 55, 35 stop. I keep close to to the limits.

 

I tried to replicate this report at lunch and no luck. I even enabled "EV Auto"; got the engine running, and; drove around long enough for the engine to stop so I could put it back in "EV" mode. The thought being perhaps something got 'latched'. Nope, accelerating up to fairly steep hills in Huntsville, the power bar never went into the red. This also includes turning on the 'heater' (heat pump.) But I had more charge in the battery.

It may be when closer to the limit, the engine kicks in by itself when under load.

Bob Wilson

 

There was some early information that dual-motor mode would only be available above a certain level of battery charge, and that the level itself might change with temperature.

I personally experienced this.

When I drove a Prime, it was out of Ev range when I got there. So, I put it in charge mode and delayed a little while. Then I started a test drive and, while on the highway part way through, put it in Ev mode. It went in fine. I'd estimate I had 3 miles or so of Ev range.

I got off the highway and started back. I took off from a light normally, all Ev. I took off from a light moderately hard, all Ev. I took off from the last light (probably down to about 1.5 miles of Ev range) really hard, and the ICE started up, just for a couple of seconds, and it stopped the instant I removed a bit of pressure from the pedal. It stayed in Ev the rest of the trip.

 

The best answer: Prius Prime hit piece on electrek.co | Page 2 | PriusChat

Enthusiasts are often very curious and sometimes about their rides.

Bob Wilson

 

I would disagree, I would say that if the intent of the car is that it should do this, then it definitely should, but if that isn't the design intent then no it shouldn't. Engineering involves compromises, there is no such thing as the perfect car or the perfect engine. I will agree that the documentation of the feature should be clear on these points so that it isn't something that surprises someone who has read the manual.

 

It's 11 miles, on normal, paved, city roads. It should be able to do that.

In my 2004, I hardly ever need to demand more than about 30kW. The Prime is supposedly capable of more than twice that in Ev mode.