Shutting off the Prius

Good question. I've forgotten to select Park myself a few times (hey, I'm just now no longer grabbing for a key...). I surmise that the "Park" button is arguably superflous at shutdown, but is still useful/necessary for those times when you need to sit for an extended time, stationary, but with the car "ready".

Being relatively new to this, I would, of course, defer to the "gurus" as there may be something more subtle that I've missed.

Oh yeah, I have noticed that the car lurches a little when I shut down without selecting Park first. Might be a clue about better practice there...

 

<div class='quotetop'>QUOTE(mtsarpilot @ Aug 10 2006, 06:14 AM) [snapback]300743[/snapback]</div>

The only reason for pressing Park first would be to get yourself into the habit, so you don't one day forget to put it in park before getting out of the car with the car still in Ready. As far as the car itself goes, there is absolutely nothing wrong with just pressing Power to shut off the car. As you have noted, it puts itself into park.

But let's say you have the car in Ready and decide to get out for a moment. If you have not put it into Park it will roll away and probably bump into something. (This is why I don't let anyone drive my car but me, except at the dealership, where I have no choice but I presume the people at the Toyota service department know how to drive it.)

 

The answer is simple..... No, you do not have to put it in Park first, just turn it off with the READY button and the car goes into PARK automatically.

 

<div class='quotetop'>QUOTE(ekpolk @ Aug 10 2006, 09:28 AM) [snapback]300754[/snapback]</div>

Keep your foot on the brake until the car HAS put itself in Park. A horribly long wait: 2 seconds or so. You can avoid the long delay in exiting the car by starting to unbuckle your seat belt during that time. By the way, the car might roll a little until the parking pawl is seated in the gears if you don't use the parking brake. I always push in the parking brake at the same time I push Power. You still need to keep your foot on the brake until it is in Park.

 

I have trained myself to push park and the parking brake for EVERY stop (no, I don't mean at stop signs or traffic lights...like pulling over to answer a phone call...or read a map...or reprogram my gps... ) because I want to be SURE I haven't left it in gear once I take my foot off the brake. And yes, I am of the "disable the d**n backup beeper. The car supplies me with more than enough visual distractions--I can't deal with audible ones as well! :blink: The parking brake thing was a little difficult to start remembering...I used to get very peeved w/ dh when he, a stick driver, would drive my automatic Acura and set the brake. I didn't believe it was necessary in an automatic car. BUT, one day, not long after getting my Pri, I leaned against the back of the car and felt A LOT of "give," and I am NOT a large person, and the car was NOT on an incline. Made me worry a bit...so retraining began!

 

i think its pretty bad for the gears when u leave the car in Park without using the parking brake on a hill

but u dont need to press P before u press Power button, i believe i saw that somewhere in the manual

 

<div class='quotetop'>QUOTE(mtsarpilot @ Aug 10 2006, 06:14 AM) [snapback]300743[/snapback]</div>

All that the park button does is disengage the CVT and put the "parking pawl" (small metal pin) into one of the gears to prevent the car moving while stopped. Turning the car off with the Power button does exactly the same thing.

(You can check it if you want - when you start the car again, leave your window down, then put it in "D"rive mode before the internal combustion engine starts and you'll hear a faint "click" as you shift when the pin is withdrawn from the gear).

dave

 

<div class='quotetop'>QUOTE(Drift Motion @ Aug 11 2006, 09:40 AM) [snapback]301369[/snapback]</div>

Can anybody confirm this?

 

<div class='quotetop'>QUOTE(InfideNino @ Aug 11 2006, 04:38 AM) [snapback]301387[/snapback]</div>

What it can do is make it very difficult, if not impossible, to withdraw the parking pawl, which is just a small metal pin that moves forward and engages a gear in the transmission (I'm not sure exactly where in this CVT). In a traditional car, you could usually muscle the thing free with enough effort, but sometimes intervention (for example from a tow truck) would be necessary to relieve the pressure sufficiently to disengage the pawl. In the Prius, with the entire weight of the car jamming the pawl against a gear, it's conceivable that the withdrawal mechanism might not have enough "pull" to disengage Park. And since it's purely electronically controlled, you can't rely on the old "more muscle" method. You'd be literally stuck. Whether or not the Prius is actually vulnerable to this ages old auto trans issue is another matter, and as a "flatlander," I'll readily defer to the "hill people." Anyway, regardless of the incline, I always get my parking brake firmly ON before I put my car in park. Brake parts are cheap compared to the insides of a transmission, and I prefer to have the brake doing as much of the actual immobilization as possible. A good solid parking lot bump can be enough to shear or damage the pawl on a car left with the brake off. Food for thought.

 

One time, on a hill, it did seem to have trouble disengaging park - took a few seconds before I could drive. I think though that the car can move forwards or backwards even if the pawl is still in.. so the engine could move the car enough to take pressure off the pawl so it can be retracted.

I do like to use the parking brake on hills though, but I have to press it really quite hard to get it to bind enough to stop the car rolling that little bit in park. Maybe it's cos of my rear disc brakes

 

<div class='quotetop'>QUOTE(molgrips @ Aug 11 2006, 06:19 AM) [snapback]301400[/snapback]</div>

Remember of course, that I'm a new guy, and no Prius expert, but it would make sense that the car could actually have D or R engaged, with the pawl still stuck in, since the process is all electronic. OTOH, in a "traditional" design, you've got to get the lever free of Park (and thus the pawl out) before you can engage a drive gear. Maybe just another of the many Prius advantages. . .

 

<div class='quotetop'>QUOTE(DaveG @ Aug 11 2006, 01:13 AM) [snapback]301377[/snapback]</div>

Nothing in the HSD drive train is ever "disengaged." The PSD, sometimes refered to in Toyota literature as a "CVT," is not really a CVT at all. The computer mimics the operation of a CVT in order to give the driver the experience of driving a CVT automatic transmission car. The Prius has no clutch of any sort and the gear teeth of the PSD are never separated (disengaged).

Park engages the parking pawl, and probably tells the computer that the car is immobilized.

 

Neutral is a full disengage of the hybrid synergy drive system, not a physical disengage, but an electrical disengage. All the physical components of the HDS system are always "in gear" all the time. That is why the manual states that you should not leave the vehicle in neutral or else the vehicle may draw down the HV battery until the vehicle ends up doing a safety shutdown to protect the HV battery. Because in neutral the HSD system no longer electrically active and cannot provide any charging to the HV battery.

In park, the vehicle is programmed to provide no motive force along with the park pawl being engaged, however the HSD system is electrically active and can provide charging power to the HV battery. To fully understand this you have to be aware that the final drive on the vehicle is connected to the larger of the motor/generators (MG2). The park programming does not allow MG2 to spin, or rather will provide no electrical power to MG2. Therefore, the vehicle goes noplace in park, even though the ICE may run for charging, during startup self test, to warm itself up while the vehicle is not moving or if you invoke an ICE run bypressing on the accelerator.

It is a good habit to put the vehicle in park prior to powering down. Part of my choice to do so is to not develop bad habits, such as turning off a vehicle, any vehicle, without sticking the vehicle in gear or park. A conventional vehicle that is not in park when you turn it off can roll freely without the parking brake on. Toyota has programmed the park pawl to set at powerdown because they can and provide an extra margin of safety, not because they want that to be your customary way of parking the vehicle.

 

<div class='quotetop'>QUOTE(mtsarpilot @ Aug 10 2006, 09:14 AM) [snapback]300743[/snapback]</div>

NO. I just press the Power button and the car shuts off and goes into park.

 

<div class='quotetop'>QUOTE(jeromep @ Aug 11 2006, 02:35 PM) [snapback]301622[/snapback]</div>

I disagree. Pushing the Park button prior to the Power button is NOT using the features of the car as it was designed to be used. It is no different than having an SKS equipped car and getting the fob out of your pocket so you can push the lock/unlock button or putting the SKS fob in the dash slot if its battery hasn't died. There is NO difference in the end result if you put it in Park yourself or let the car do it.

Now, if you are concerned that you will get so used to turning off and leaving that you might forget to put a regular car in Park some day, then go ahead and push the Park button.

 

many times i have just hit the power button and started to get out only to find the car still running and moving forward.it dont always shut the car off.last time was 3 days ago and just missed hitting my water softener.
yesterday i started to push park 1st and so far it shut off every time.
this was also the case with my 2005 prius.

 

<div class='quotetop'>QUOTE(daniel @ Aug 11 2006, 07:12 AM) [snapback]301457[/snapback]</div>

Whoops, you misunderstood me - by "disengaged", what I meant was "no longer provides drive power to the wheels".

Dave

 

Another newbie question:

Do you think it's a good idea to turn off the air conditioing and/or radio before shutting off the Prius? The Toyota sales rep that test drove the Prius with me said it was okay to leave them on... when shutting down the car. In my previous vehicles (non-hybrid) I always used to turn off the a/c off right before turning off the car. I'd heard it was not good to start up the engine with the A/C in the on mode. Is it different with a hybrid vehicle? What do others here do?

 

<div class='quotetop'>QUOTE(riva @ Aug 17 2006, 02:29 AM) [snapback]304564[/snapback]</div>

In conventional cars, the AC compressor is coupled to the engine by mechanical means, and can add extra load to the engine particularly when starting up/warming up. I doubt it would cause an issue, but I suppose it makes some sense to let the engine warm up before adding extra load.

On the Prius it's an electric AC compressor which doesn't directly connect to the engine - there's nothing wrong with leaving it on all the time (I always leave the "auto climate" enabled in my car unless the weather is nice enough to cruise with the windows open).