How will a PiP Perform in Hilly Terrain?

From someone who has taken his PiP to the top of Pikes Peak, I can tell you it will perform very well.

1) Regardless of the battery state of charge; you will always have ample power to get to the top. The only difference is how the car behaves while delivering the requested power.
a) Full battery- car will use the gas engine at a low to mid level of the rpm band. The battery will provide most of the power for the electric motor.
b) low battery- the car will increase the engines rpms to generate the power for the electric motor. The main difference is that the lower the battery pack the higher the engine's rpm will be.
2) If you are on a step freeway such as I-70 from Denver to the Eisenhower Tunnel (Continental Divide). The car's engine RPM will remain very constant and in some cases a bit high. Just understand that it is normal and will not harm the engine. This is a bit of an advantage over a regular car. The Prius can take the engine to the RPM that suits the particular situation and keep it there. A normal car has to upshift and downshift to keep you in the desired speed. In some cases it can result in a lot of gear hunting.
3) Going up I-70 or Pikes Peak, I depleted the charge on the way up; this was done intentionally to take advantage of the regenerative brakes on the way down. Coming down from Pikes Peak with the shifter on B-mode, I was able to fully charge the battery up to 13.6 miles of range. Once it was full, the engine was engage to provide engine braking. The engine can reach high RPMs during engine braking if your battery pack is full. This is to done to provide maximum engine braking while preventing the batteries from overcharging. Needless to say that as long as you use B-mode you will be fine. My brakes were very cool by the time I got to the bottom of Pikes Peak. We were the only car allowed to continue down the mountain after having a break temp check at the checkpoint. The rest of the cars in front of us had to pull over to the brake cooling area.
**BTW- B-mode can be modulated with the accelerator pedal. It goes into full engine brake when you lift your foot of the gas completely. However, as you apply the gas it will start to reduce the engine braking until you get to the point where it switches to gas and accelerates as normal. In a sense, you could drive all day long with B mode and not cause any issues to the car.

4) Engine and hybrid systems temperature- The hybrid system has a very good cooling system; like any other car it can get hot when going up steep inclines for extended periods of time. I experience this going up to the top of Pikes peak. The engine would not turn off and the cooling fan ran at a very high speed for most of the way up. We did turn the A/C off to ensure that maximum cooling was being provided by the radiators and fans. I would suggest leaving the car on for a few minutes before turning it off at your destination if you put it through a heavy work load.

 

I am not a PIP owner, just two 'normal' Prius.

1) yes, use EV mode
2) the PIP can use regenerative braking for over a 2000 foot descent, so it should recharge all it can. I find the cruise control works to avoid speeding up. If you DO 'fill' the battery, it will use engine braking to reduce friction braking.
3) yes, you have a 98 HP engine even without much battery power.
4) EV tries to use mostly Electric power, HV uses Hybrid power Within HV you have Eco, Normal and Power, but they may not effect electric usage.

Bring your commute, ask the salesman for a test drive of you commute. My salesman let me drive about 70 miles, overnight in my Gen 2 prius.

 

I think the main thing to remember is that it might get noisy with the engine staying at a high RPM. This is normal and the car is doing what it is supposed to do. When going down always use B-mode and use the gas pedal to modulate how much engine braking is being applied by the car. You will find yourself using the brake pedal on rare instances.

One advantage of the PiP is the Lithium-ion battery packs ability to hold more energy. It allows the car to run more smoothly on this type of terrain. My 2005 Prius was a lot noisier than the PiP since it would go through its battery pack a lot quicker. Both cars tackled hills like nothing thanks to the ample torque provided by the electric motors. It is just that the PiP handled that type of situation al lot smoother.

 

I can speak to running on hills in pure EV mode. I live in a hilly area, with a 4.2 mile route between my fiance's and my place. There's a 1 mile, 350 foot gain hill (along with some smaller, shorter hills). If I do a round trip, I start with around 12 miles of EV estimated. When I get to the destination at the bottom of the hill, I have about 7.5-8 miles left. Upon return at the top of the hill, I have about 1-2 estimated miles left. So there's a penalty for hills, but regen does capture a lot back if you're doing round trips.

 

Since the B mode uses engine braking you won't be getting as much recharge as is available for a given downhill. Stay in Drive, if engine braking is needed because you are going over 62 mph or the battery is fully charged the computer will manage that. Don't try to out think the computer

 

The plug-supplied electricity will be taken advantage of, even when the engine runs.

 

I am not sure exactly what advantage B mode would provide going down the mountain, that lightly "riding" the brakes wouldn't. Braking on the PiP uses regeneration as much as it can. Pressing the brake pedal doesn't necessarily activate the friction brakes, any more than pressing the throttle necessarily makes the gasoline engine run faster. Lots of computers at work.

 

Charles if he is descending farther than the capacity of his battery (600 feet in a normal Prius, 2000 feet in a PHV) then B mode allows him to use engine braking even before the battery fills. Also a plus if the descent is so steep he is looking for ways to slow the vehicle.

 

PiP would do full regen (without engine running) in EV mode B gear, until the battery is full. Only then, the engine braking would start.

So why not just brake until it is full? B gear does not cancel (perhaps it resumes) regen if you happen to run over a pot hole. That's the advantage I found.

 

I've driven my PiP over Patchen pass in the Santa Cruz mountains (California) a couple of times, and it performs well (albeit a bit noisier than my 6 cylinder Camry going up the hills) I usually leave from work with a full charge and leave it in EV going 50 or so up the hill. the car switches to HV mode about halfway up when the battery runs out, runs fine up the rest of the hill then charges back to 4-5 miles or EV by the time I'm down the backside of the hill.

 

I love the Pacheco, I drove the first generation Prius I tested over it like it was a '75 BMW 2002, so I know the road and my own 2005 has been through it and 377,000 more miles mostly Tejon pass 4144 climb.
A lot has been said here
So let me add my 2¢
Do use all the battery you can before your decent.
Do use your highly successful
regenerative breaking on the down hill. Engine breaking is just more friction ( I find as I descend the last 1000 feet of the 4000 that my battery is full and can take no more this is the only time I use the B drive mode to keep my from being worn, I've checked them with a IR thermometer after the decent. Here is what I learned:
In freeway driving my break pads are only used in emergency stopping ( this is why I get over 150,000 miles before I down to 10%) on long descents B mode causes a strange smell when the engine starts back up (I do not know why I expect vacuume draws oil into the cylinder with 0 combustion it waits till restart to burn) so I use it infrequently or only when battery if full and I need to slow it down (WAZE report police ahead)


iPhone ?

 

This has been discussed before in this forum, but I am afraid that I don't recall all the conclusions. The question is what exactly B mode does in a PiP. It's main behavior seems to be to cause more aggressive regeneration when your foot is off the throttle than in D mode, and thus simulating what B mode does in a conventional car with an automatic transmission: engine braking in a lower gear. Truck drivers downshift their manual transmissions to get the same effect; I think they call it a Jake Brake. I think the observation in the PiP was that compression braking (turning the engine without fuel, but with compression), was only observed after the battery is full and thus regeneration is not possible. In general, the friction brakes are the last resort, if regeneration and engine compression braking is not enough. With engine compression braking, energy is dissipated by compressing air, which gets hot, and just tossing it.

 

Charles, I can relate with your observation. Recently, I dropped into B gear around 50 mph and ICE Jake braked. Then I realized the battery was nearly full.

The behavior is due to the bigger battery ability to regen brake more power and longer storing more energy.

 

I drove my very overloaded PiP across West Virginia on scenic byways from northern Virginia to Kentucky this Memorial Weekend. "Overloaded" = 120+ cement patio pavers, plus other tool gear. Going up 7%, 8% and 9% grades with this heavy cargo load, the PiP pulled like a John Deere tractor. IMHO the PiPs' partly charged Li-Ion traction battery contributed the unexpected (and very welcome) gobs of instant torque, whatever the road speed. Note: I used the POWER Button extensively for better throttle response.

 

Bearing in mind that the process that converts rolling energy into electricity, then stores it in a battery, then converts it back to rolling energy again in a hybrid is only 31-33% efficient, it's unlikely that the mileage over rolling terrain would be as good as that on the flat-and level.

Still, a hybrid runs circles around a regular vehicle in hilly terrain, because all the energy acquired from climbing a hill is wasted on the descent as excess heat.

 

I always get better mileage in hilly terrain with my PiP. However, I suspect its a combination of much slower average speed (which is always better mpg) and the many regeneration opportunities.

 

Hmmm... I did a mountain pass last week for the first time with my PiP. When I made a stop on top of the mountain pass to let the traffic pass and get a stretch, I noticed a strong smell of something burning. No smell in the cabin. Only outsite.
I was too proud to lift the hood of my brand-new-PiP in public. So I just left the car in Ready to resume cooling on it's own.
The local Toyota dealer guessed it was probably only some residue from manufacturing process burning off. This was the first time the car actually drowe in PWR zone for ten minutes after all.

Other than that, the car did really well. I could drive faster up the hill, but with this car you start thinking more MPG-aware, want it or not.