Why does the ICE turn on sometimes when I put it in Park?

The engine decided at that moment, by co-incidence, that it needed to warm itself up.

 

I notice that too; I don't think it's a bug; the HV ECU probably had wanted to start the ICE anyway, either to maintain temperature or state of charge, but hadn't wanted to badly enough to do so in gear (where no matter how well it coordinates MG1 with an opposing torque from MG2, you're still likely to feel a bit of a jolt). My guess is they gave it a lower threshold for deciding to start when in park, because then MG1 just acts against the parking pawl and the start won't jerk the car.

It does turn out to be pretty futile the way I drive anyway, since about the only time I shift into park is just before taking out the key.

-Chap

 

a lot of times, when i pull up to a light, my engine will continue to run. then, when the light turns green, as soon as i let off the brake and step on the gas, the engine shuts off for a second or two and then comes on again for power as i accellerate.

 

Unrelated vehicle, obviously, but my 2010 Honda Insight would always do that. It would run the engine constantly when in park, even if it was off before shifting to park. i found it highly irritating.

 

Honda Civic Hybrid tactic when parking: pull into spot, wait for AutoStop to initiate, turn key to kill ignition, then shift into Park. Other way 'round, shifting to Park first: it fires up again, for frustrating second or two.

 

I recall that the reason for the Classic gasoline engine spinning up when you shift to P is to help calibrate the engine ECU. 2G does not do this.

 

maybe if the gen III did it, it wouldn't have the crazy startups.

 

Hi there, I am just curious why this is of such concern? Are you a new owner? Don't get me wrong, I am not being mean in anyway, I am just curious and hope to change your mind as to why this is annoying when its actually a very cool thing about our cars! : )

My Prius almost never does this in summer. Mostly in winter. It will do this however, if the battery SOC is low enough in any weather, when shifting into park. However, just let the car do what it needs to do. It is doing its absolute best at all times to prolong battery life. My car has 200,000 kms on her and the battery is 100% perfect. Ask yourself, would you rather waste about $0.02 of fuel that it took to start you car for that small period of time to calibrate, or replacing a $2000 battery simply because you did not want to let it get calibrated? That is just my opinion. I find it in no way annoying, and in fact find it impressive that Toyota programmed such a contigency into a first generation car like the G1 Prius. The newer Prius's get away with such things due to superior advancements in battery and ecu design, but given the nature of the way our THS works, I think its pretty good.

 

There were actually multiple potential "housekeeping" tasks the Classic model would perform upon shifting to Park. That was totally normal... and yes, welcomed later when the redesign eliminated the need.
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Well, if you want the systems to do their "housekeeping" activities, then you will allow the engine to run until it decides to turn off on its own.

 

Well . . . I wouldn't go so far as to say the Gen2 eliminated ALL the housekeeping tasks. We DO have to deal with that whacky 8 seconds stopped, in order to permit stealth below 35mph . . . even though temps ought to permit S4 without you having to come to a stop. But each generation does seem to get a bit better.

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