How to properly warm up the PIP ICE

This is what I have gathered from my 3 month experience.
EV back roads, enter highway ramp, toggle HV, and engine starts. During this time EV drops, and you accelerate. The engine seems to be in warm up mode for about 30 seconds. While this is happening, I am getting 80 MPG, so I know the battery is pushing the car. After the initial warmup, I can hear a change in the engine (I am sure a scanguard device sees the RPM changes). I then notice MPG drop to about 10-15, and the EV battery begins to recharge. The battery will charge to the point where the ICE was switched on. The time of recharge for me takes about 7-10 minutes, driving on the highway.

Today, after the initial 30 seconds I decided to toggle the HV switch, putting it into EV, and then toggled again back to HV. Once I did this, the engine stopped "recharging" the battery, and went back into normal hybrid mode. I basically saved the MPG or gasoline from recharging the engine and achieved 111 MPG which is normally 93-96.

There are many other posts about this topic, and am sure others have there own ideas. This is just my experience.

Mike

 

John has a lot of data with this, and I am sure he will respond at some point with your answer.

I have tried pulling over and letting the battery charge, increases roughly .6 mi.
I have tried warming one mile on the backroads before the highway.
I find it best to just turn the engine on when entering the highway, this is where i receive the best MPG. I also beleive the car protects itself during the warmup, which is why the batter is initially used.

Lets see what John and others think.
-Mike

 

i hit hv before reachung the ramp so the ice is warmed when i need it and i don't put a big drain on the battery. of course the time for warm up gets longer as ambient temps drop. now, i give it a minute acouple in the fall and 3-4 in winter if i don't have the heat on! a scangauge would give you the engine temp so you would know exactly when to do things.

 

I wouldn't worry about over-revving the engine. It's under computer control and there's very little, if anything, that you can do to it that would hurt the engine or the hybrid system in general. Just drive the car.

 

This might only relate to my limited experience with a GenII car, but the more I let the car use both the engine and the electric motors at the same time, the less gas I use to recharge the battery after the engine warms up. Overusing the battery in EV mode when the engine isn't warmed up in my GenII equates to really bad MPG mpg results... And of course with a PIP you can deal with that by plugging in your car, but not until the end of your journey.

And I know a plugin is entirely different than my GenII but one thing that isn't is that running a cold engine to accelerate onto a freeway is engine abuse. The first five minutes of warmup of a cold engine is where the majority of all the wear and tear happens... Also a cold engine means a cold catalytic converter and they don't work when they're cold (so you pollute more). And of course the PiP accounts for all this stuff so you don't have to but if you want your engine and battery pack to last as long as possible it's best not overuse or abuse either of them...

 

My understanding is that traditional ICE "cold start" wear is due to starting the engine at low RPM since starter motors are relatively small. The Prius Liftback/Plug-In avoids this wear, b/c it uses a much larger traction motor to get the engine to higher RPMs before the engine starts. You can feel the roughness of a traditional ICE start vs the much smoother engine start in a Prius. So I'm pretty sure engine wear due to cold starts in a Prius is a non-issue.

 

Also in the Gen II you have the thermos-type system which stores coolant from the hot engine for 72 hours to aid in faster warmup on the next cold start, in order to minimize pollution.

 

There is warm up of the cylinders which affects emmissions. The car handles this very automatically and very quickly, in just a few seconds.

There is warmup of the wearing surfaces like gears and bearings in the ICE. This include warmup of the coolant beyond the 130 degrees which is the cutoff for the ICE. This affects the viscosity of the lubricating oil and grease along with the operating clearances of metal to metal contact. This requires a much more thorough warmup. The best plan is not to accelerate hard for several minutes after the ICE comes on unless there is an emergency requiring that.

Actually, one of the best features of the PiP is that it comes close to eliminating the bad effects of driving with a cold ICE, especially on short trips. This is one of the main reasons I chose the car.

 

Interesting, I didn't know that... But it's just basic engineering that all of the parts in a cold ICE engine don't fit together very well and you get excessive wear and low MPG until the engine is at optimal operating temperature, which is when all the parts are at their optimal size and shape in relation to all the other parts of the engine, especially the piston rings. I assume Prius' still have piston rings?

Anyways, point being is that racing your engine at high RPM's when cold will always cause more wear and tear over time than waiting for the engine to warm up first before you do hard accelerations.

 

With a ScanGauge, it's easy to see how protective the system is of the gas engine, taking advantage of the robust nature of the electric motor. During warmup, the engine RPM is limited to 1500. That's the squeezing.

Once warmed up and still in HV mode, you'll see the RPM change. The engine will then run hybrid mode, but with a persistent charge approach to replenish some of the EV just consumed. Then later when you exit the highway, more will be restored.

If you press really hard on the pedal, the engine will be allowed to rev up to around 3000, which is well under the 5500 max.

If you switch back to EV mode prior to warmup completion, it will remain at 1500'ish, then drop to about 992 for super efficient engine-assisted driving at speeds faster than 62 mph. We've been referring to that as EV-BOOST mode, since the MPG is above 100 even at 70 mph.

Long story short, the engine is well protected.

Note that the regular model Prius does something similar in the winter, favoring the electric motor to allow the gas engine to warm up gracefully.

 

Of course. However, they (along with other components within) are lighter weight than usual. That's great, since it's more efficient and the engine is babied... never having to endure a full pounding like a traditional vehicle.

 

Wow!!! That's flipp'n amazing!!! I totally want one!!! Guess I better go buy another Lottery ticket so I can afford to buy one!!! ;-)

 

Also, the gasoline engine uses an Atkinson cycle, which trades off power for efficiency. The computer controls the engine; all you can do is ask more more power by pressing on the accelerator pedal, and the computer figures out the best way to honor your request.

In California we have to take our cars in for Smog Emissions checks as part of our annual registration renewal. But hybrids like the Prius are exempt from this hassle, since they are inherently so low emission.

 

Yes, in California the PiP is exempt from smog testing.

 

What about regular Gen3's?

 

My Gen I (2002) is exempt, so I can't imagine it would be different for any other Prius. Don't know if this reason still holds, but back when, they said that Prius was exempt because there was no way to execute the smog test scenario, which required running the gasoline engine at a certain RPM and measuring the emissions.

 

Concerning engine wear at startup, does anyone know if the PIP ahs an electric oil pump or an oil accumulator to pre-lube the engine before starting? And, I think California will start smogging older hybrids next year.