PHV: Is "all-electric" the only mode?

no. there are plenty of write ups here from people who have driven them fairly extensively. you may use gas during the capacity of the batteries if the computer feels you need it. as with the prius, toyota sets up the computers for most efficient use of power with consideration to safety and protection of the battery etc. as it comes into use, people will figure out how to drive/hack it for best mpg's.

 

The PHV doesn't try to be an electric-only vehicle. It's a hybrid at heart. True, you'll find in a number of circumstances it will keep the engine off, but that's the result of that being the most efficient choice for those conditions.

My commute to work in the PHV was on a 70 mpg highway. Having used the battery entirely for that wouldn't have been the best use of the hybrid system. That's why the engine spins up for assisting opportunities then. That particular drive was 16.5 miles total, 9 of which were in the 70 mph range. The overall average for that was 166 MPG. Notice how a tiny bit of EV was still available right before I finished the drive:


The system seeks out and takes advantage... the best of both worlds. Then when the EV is depleted, you go back to regular Prius driving with the usual modes of choice.
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Evan

I watched the video of you driving the car. Please clear up a point in this regard. Were you able to operate in electric only for a few miles in city traffic without starting the ICE? Must you drive so gently to do that as to be a traffic hazard?

Allan

 

I accelerated from a dead stop at the bottom of a step hill, got to 40 mph, then continued the climb.... all using only electricity.... without any special effort. I just drove it as I normally do, which for perspective takes 2300 RPM to climb after accelerating.

In other words you'll notice a lot more power from the electric motor than with the cordless model.
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If you search Tony Schafers Post, he describes one week of typical driving with the PHV. He generally exceeded expected mpg by 10 to 30 mpg AFTER the battery was mostly depleted. I think one figure quoted was 80+ mpg. Makes for very interesting reading and a great contribution on his part.

 

My understanding was the test mules were set up that way (to minimize redesign of the HSD at that stage), but I suspect the PHV won't have two different large capacity batteries but make efficient use of one. Should save weight and space that way.

 

or ... put another way, there is no user selectable option for gas/electric DELIBERATELY built in to the PHEV Prius. On my test drive, I monkeyed with the notion that if I wanted to force the ICE on ... even on a warm drive, I could simply turn the heater on ... which fores the ICE to warm up to more efficiently provide heat. Of course you KNOW what the down side of THAT is.

Still, the fact that this command is part of the car's programming means there'll be a way to hack into the PHEV's programming so that you can turn the ICE on maybe in other ways too.

 

I hear gently stroking it while whispering into the intake helps.

 

Maybe they should make it an option like they did with the EV button. That way people who can plug-in when they get to their destination or just want to drive it don't have to pay for it.

 

Let's say that I was planning a drive from SF Bay Area to LA, about 400 miles (or anywhere that's all highway). If I had a PHV all charged up and gassed up, it would run in EV during my 1 mile trip to the on ramp of the local freeway.

While accelerating onto the freeway (going over about 62 MPH or maybe before that speed, not sure), the gas engine would come on and stay on. Assuming I stayed on the freeway at 65 MPH or so all the way to LA, I should still have all the EV range left after exiting freeway in LA, minus that used to get to the freeway in the beginning.

Correct if wrong, but above makes sense to me.

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In reality, you'd likely make a rest stop or hit slow traffic on way to LA and it would use more EV range under those conditions.

I'm sure the PHV does not use up your 13 mile range in the first portion of the trip - it cannot be using EV mode while your on the highway over 62 MPH IIRC.

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I mostly see the Prius PHV as a hybrid with much greater EV capability.

 

I do believe you are wrong. Even when the ICE comes on during the AER, the primary power source is depletion of the PHEV battery, supplemented by the ICE (or there is some conjecture on these forums the ICE will just spin without fuel going to it at all). The battery will still be depleting. Once the state of charge is sufficiently low to terminate "EV" mode, the algorithms will switch and the primary source of power will be the ICE supplemented by some electrical power from regen, etc...

The thing to remember is its never "all in" as it were. The ICE can run (or at least spin) at some times while in "EV" mode, at the same token there will be times in hybrid mode where the ICE does not run (stop and go, lots of regen, extended downhill, etc...). Whether the ICE is running or not does not determine what mode the car is in, what the primary energy source is does.

For instance in your example if you get on the highway in 1 mile of EV and run at 70+ mph until out of gas, you may get a couple miles of safety buffer out of the car before grinding to a stop, but its not going to be 10 miles.

 

Ok. Then as said before, PHV raises EV capability quite a bit, but car is still a hybrid.

 

That is the best way of thinking about the PHV, operating in two different hybrid modes, one primarily electric with some mechanical assist, and one primarily mechanical with some electrical assist.

I think the results will be quite extraordinary. In a few years I really don't see "conventional" hybrids being able to compete in the market place.

 

It was reported that the production version would have the HV button. That will allow you to save the EV miles and run on HV mode whenever you want.

 

The bottom line is the hybrid that runs with half the engine and another that uses both by blending the two. I think the hybrid that uses half the engine will extinct.

A well balanced vehicle at a reasonable price will get more sales. I don't think the ratio of power from the plug vs. the pump would matter much.

 

Charge Depletion (CD) and Charge Sustain (CS) modes can sum it up. The prototype Prius PHV starts in CD by default. It uses the PHV battery as a primary source until it runs out. It switches to CS mode after that. The production model is reported to have the HV button so you can override it into CS mode.

I noticed there was a transitional (T) mode that could be exploited. It can amplify the P&G efficiency boost, if you can maintain in that mode. You use the ICE to accelerate and you have a much powerful battery pack to maintain speed longer. Regen brakes capture more energy so you can stay in the T mode for a long time.

Using two engines makes Prius fun to drive, sort of like manual transmission. You can influence and control which engine to use. The computer ultimately decides the best for you so you don't stall the engine or kill the battery pack, etc..