ICE in Reverse?

The ICE turns on to warm itself up. This happens whether you want it to or not, unless you hit the EV button and EV mode is available.

EV mode won't be available dependent on some conditions such as if the ICE is below a certain temperature, the HV battery is above a certain temperature, the heat is on, etc. In that situation, the ICE will always start regardless of your preference.

 

The ICE is used to generate electric power using one of the MGs to drive the other MG in reverse. Your Prius is a serial hybrid when going backwards.

JeffD

 

Mine doesn't. The only time that the engine runs when I am in reverse is when it is warming up. Otherwise reverse is electric only. It is my understanding is that this is how it is designed.

 

Yeah, I agree with Corwyn. When you're in reverse, MG2 (the main electric motor) moves the car. If the ICE is on when reversing, it's usually because you just turned on the car, so the car runs the ICE to warm up everything up, assuming you'll continue your voyage longer than a few seconds. The ICE does not at all power the car in this case.

That's why if I have to move the car to the driveway, I throw it in neutral the second the "ready" light pops up, and a few nice gravity-aided swoops later, I'm parked in a new location without the engine having to turn on. Now moving it out of the driveway is another matter...

 

This depends on how far you need to back up, and how much charge you have in the HV battery. If the HV battery SOC is high enough, the Prius won't start the ICE unless it does so for heat. However, once the SOC gets low the ICE comes on to supply power. In this case it is indeed a serial hybrid.

Backing up, the serial hybrid mode of the Prius is not very efficient. Since the torque split through the PSD is fixed, the ICE tries to move the car forward while MG2 moves it backward. MG2 wins, but it's not very elegant. Fortunately, backing is not a common form of travel.

Tom

 

It is my understanding that when the hybrid system is turned on, the ICE runs as soon as the coolant has been pumped from the thermos into the engine, for as long as it takes to bring the catalytic converter up to operating temperature. Backing up is often the first maneuver of a trip, so it appears to start when backing up. It starts at about the same time after power-up, even if the car is moving forward, or if it's not yet moving at all.

 

If you back into your parking spot at the end of your trip, you'll avoid the need to back out at the beginning of your next trip. It's a double win:

1. the warmed up car is more fuel-efficient backing up than the cold car,
2. less likely to get in a collision backing into a spot than backing out of a spot.

 

it's for emmisions, it tries to warm itself up before you take off onto the roadway. It's preventing a cold ICE start when someone may leave their driveway and have to start going 50mph on a cold ICE.

 

The -correct- answer is buried up there in all those messages.

First, it's a GIII so no pumping of coolant.
Whether the A/C system is demanding heat or not and whether the ICE is warm or not, AND whether the cat is warm or not, the ICE will run to warm up the cat, for a minimum of about 20 sec. EVERY TIME you shut down the car (go from "ready" to off) and start back up (put the car in "ready").
Yup, it could be considered "a waste". But it's required to meet the EPA rating Prius has earned.

So just tell yourself "It's all good!"

 

i seem to remember that the ICE has to reach 100 deg F before it shuts down.
mine also want to run for abt one mile after i start it up from a short stop.

 

Don't see that. It's timed or cat. sensor defined, not temperature of the ICE. Pearl shuts off the ICE even if the ICE is still at 45C or lower, for example.

Also note that the car is rather "limp" for about a minute, perhaps less, from a cold start. This to keep the ICE from running at power to keep emissions down while cold. I suspect this is why many reviewers think the Prius is gutless. It isn't, it just has certain "different" operating methods, such as a slight delay when you floor it. It WILL "scat" very well. I often leave traffic behind at lights.

 

FWIW, I see with my SG that the engine will shutdown, if it can, @ 103 degrees every time in ECO mode.

 

Picking up on an old thread but, I wish this was something better explained to new Prius owners. I almost got stuck in a driveway with a very steep grade, when I had to back out of it. I did not realize the ICE cannot assist in backing up. I had to wait for the battery to charge and the ICE to shut down before I could back out.