HV mode Prime vs 'vanilla' Gen4

1. I've seen HV mode consume traction battery

2. I believe the Prime has a more powerful MG2 (or is it MG1?) so it can accelerate faster without the ICE than the Prius.

3. The ICE is a little buzzy sometimes. Also, the throttle response seems slower when the ICE is running.

4. It's flat where I live and I can easily get 60-70 mpg (according to the car) with suburban driving in HV mode (mostly staying under 45 mph). It's way better than I expected.

 

#1 Yes, but only a little (2-3% SoC) during the time the engine goes through a warm-up cycle. Otherwise, it will maintain the SoC level. Or it can even gain SoC while in HV mode if there is substantial regen.

#4 Beating EPA number is easy on PP. I don't know if it is harder on Gen4 or not. Some people claim PP with charge left in the traction battery gets better mpg on pure HV mode. I tried comparing it under my own driving condition for my commuting. For small numbers of trials, I did not see a noticeable difference.

I have never driven Gen4, so I can't comment on #2 and #3.

 

For more details to Q #1 - if you were in EV and had 10% SoC and switched to HV, the car will maintain that SoC +/- a couple percent.
If you go down a long hill and regen a significant amount, say 30% SoC, the car will run in EV mode until you're back to 10%. Or you can switch to EV mode, then back to HV, and your new "equilibrium" SoC would be 30%. "banking" the regen for later use

HV mode tries to maintain whatever SoC you were at when HV mode is started.

 

As has already been well answered, whatever the SOC when you enter HV mode, that's the SOC the car will use for its baseline. In HV, the Prime will make good use of the battery at speeds under 60 mph as it alternates between ICE on and ICE off. That will cause the SOC to vary as it goes above and below the original level.

We have a regular Gen 4 with a NiMH battery as well as the Prime. I don't drive the regular Prius all that much, but as I recall, it will let the HSI indicator go above the middle line before the ICE comes on, but it's not as "athletic" as the Prime. (We never put it into EV mode with the button unless we're just moving it a few feet.)

My Prime almost always has a smooth transition when the ICE comes on or shuts off. I'll notice it if I pay attention, but it's pretty slight. As for EV Auto, I can't answer since I never use it.

My Prime gets considerably better hybrid mileage than my wife's Prius. It's flat where we live, but it does even better when we visit places with mountains. Not that I get much chance for hybrid mode. I'm over 1,100 miles so far on this tank and still have over 7/8 of a tank. (I need a road trip!!)

 

Apparently, you'll need to buy a new display from Canada.
Anyway to change outside temperature from Fahrenheit to Celsius? | PriusChat

 

Just remember the displayed mpg on all Prius is inflated. I get a feeling that PP's display is inflated more than Gen3 which was 5-10% higher than calculated. I believe the EPA number is based on the real value under testing conditions used. When I do a full tank of HV only drive (no charge for the entire tank) with PP, the calculated mpg by a full tank method which is the golden standard of mpg calculation gives the mpg very close to the EPA number.

 

Toyota gets free fake news from owners, who tire of converting the inflated mpg numbers, or were unaware, or favour the rose-tinted view.

CleanMPG owner (I think) Wayne Gerdes test-drove a pre-production 4th gen, and noted displayed mpg was spot-on. Presumably the 7%~ “tweak” comes later in the development process.

 

So far for three brands Toyota, Nissan, and Honda all hybrid, Honda gives the most honest mpg display. Nissan's display is just as inflated as Toyota's.

 

That was my experience with 06 civic hybrid: the cars foibles aside, the mpg was accurate.

It’s funny how Prius owners will try to rationalize the “error”, saying its gas pump variations, or whatever. The smoking gun though, is the consistency of the error.

 

Actually, they are thermistors that change electrical resistance according to the temperature. Thermistors are accurate, but they need to be properly located. When you see 107F on your car's dash, that IS the temperature at the sensor. (And not far off from what you'd feel if you got out of the car at a traffic light.) Locating the sensor two feet above screaming hot asphalt that's re-radiating heat is not a good place. So, they are pretty accurate when it's cool, but when the road surface gets hot, the sensors don't tell you the temperature over in the shade under a tree; they tell you the temperature where they are which is practically on a frying pan. If anyone comes up with a way for the car to know how much to compensate for that radiated heat, they will become very rich.

I understand that some cars have better locations for the sensors, but the best location would be under a shade tree somewhere and about six feet above the ground as opposed to two feet above the pavement.

 

They have to find somewhere to spend all the money they saved taking away the illuminated lock and window buttons on the driver's door. It wouldn't feel quite like Toyota if they didn't cost cut driver conveniences while ignoring cost-cutting opportunities that would add convenience.

Both of my Prime's outside temperature displays have been nearly always the same reading as my Davis weather station, sometimes being off by a degree.

You can get sensors that are very accurate and inexpensive. For example, the Sensirion SHT30 is accurate to ±0.2°C and can be purchased retail for as little as $1.90 each.

 

A note on point 2, for the gen 3 prius. My experience with the gen 3 prius is that the system will keep the car in EV, even after first half of the HSI, when the SOC is full. In these conditions, it seems to favor draining the SOC fast, by maximizing the use of the traction battery. I've even seen it go up to 85 km/hr in pure EV (and my pure astonishment as well).