Gas engine not cycling on properly

[Psi296]

It also won't stay on when you let off the gas pedal while in park. It revs up but then shuts off quickly. THis cause my battery to run down to 2 bars and the gas engine still won't engage.

Has anyone heard about this?

[efusco]

Sounds like it's working fine. It's not supposed to come on unless the battery charge drops very low (1-2 bars depending upon whether the heat/AC is on etc.) or you're actually driving.

This is a good thing, burning gas when you're not moving is wasteful.

[Psi296]

But when the ICE does engage, it immediately shuts back off without even attempting to charge the battery...basically if I don't press and hold the gas pedal, the gas engine will not engage.

That can't be right.

[ghostofjk]

No, with two bars showing on the HV battery, something's not right. How many miles have you driven it?

[efusco]

<div class='quotetop'>QUOTE(Psi296 @ May 12 2006, 08:01 PM) [snapback]254459[/snapback]</div>

But when the ICE does engage, it immediately shuts back off without even attempting to charge the battery...basically if I don't press and hold the gas pedal, the gas engine will not engage.

That can't be right. [/b]

It is right. There is no reason it should/would "charge up" the HV battery. The ICE will run briefly to reestablish a reasonable SOC (1-2 bars) then shut off again in anticipation that you will start driving again soon. At that point it will engage its normal algorythms and get the SOC back up in the 4-6 bar range.

Don't get caught in the trap of thinking that the battery 'needs' to be at a certain SOC.

Your car is working fine. My suggestion to you is to avoid situations where you're just sitting with the car in READY mode and not moving or going anywhere.



<div class='quotetop'>QUOTE(ghostofjk @ May 12 2006, 08:09 PM) [snapback]254463[/snapback]</div>

No, with two bars showing on the HV battery, something's not right. How many miles have you driven it?

[/b]

Sorry, I think you're mistaken. If it only stayed at 2 bars even with normal driving I might agree, but he's talking about when the car is sitting going nowhere. The battery will, in those cases, drain down to 1-2 bars and go through the very brief ICE run, then shut down sequences until you get moving again and the SOC will not often go above 2 bars...I've rarely seen 3 in those occasions, but usually just 1-2.

[darelldd]

<div class='quotetop'>QUOTE(efusco @ May 12 2006, 06:51 PM) [snapback]254483[/snapback]</div>

It is right. There is no reason it should/would "charge up" the HV battery. The ICE will run briefly to reestablish a reasonable SOC (1-2 bars) then shut off again in anticipation that you will start driving again soon. At that point it will engage its normal algorythms and get the SOC back up in the 4-6 bar range.

Don't get caught in the trap of thinking that the battery 'needs' to be at a certain SOC.

Your car is working fine. My suggestion to you is to avoid situations where you're just sitting with the car in READY mode and not moving or going anywhere.
Sorry, I think you're mistaken. If it only stayed at 2 bars even with normal driving I might agree, but he's talking about when the car is sitting going nowhere. The battery will, in those cases, drain down to 1-2 bars and go through the very brief ICE run, then shut down sequences until you get moving again and the SOC will not often go above 2 bars...I've rarely seen 3 in those occasions, but usually just 1-2.
[/b]

Agreed! This is how it works by design, folks. Don't fight it. Be happy.

If you really WANT that ICE running all the time, you've purchased the wrong vehicle.

[TonyPSchaefer]

Some others have reported similar experiences. Some while driving, others while parked. I usually shrug it off as the car being indecisive (not technical, but people can understand it).

It's as though the car says, "my battery is low so I'll run the ICE but I'm not moving, so I'll turn it off but it's a bit chilly so I better turn on to heat up but we're in park so I'll turn off but the battery's low so I'll turn on..."

After almost two years of driving my Prius, I am certain that there's nothing wrong with your car. I have more of an issue with your car having only two bars remaining. Just how often do you have that situation and what are you doing to get to that state?

[qbee42]

Evan and Darell have it right. Your ICE is doing exactly what is supposed to do under those conditions. There is absolutely no reason it should charge the traction battery while you are just sitting there, unless the SOC gets very low.

Tom

[Psi296]

Thanks for the responses guys.

In response to your questions, I have 4700 miles on the car. Even though traffic here in Baton Rouge is usually a nightmare...I have never experienced the battery getting that low...or just haven't noticed it if it has.

Today was unusual, it was very hot so the A/C was on full and I was stuck in standstill traffic due to an accident, so I was just sitting there and noticed that only 2 bars on the battery were left and the ICE was doing nothing and I guess I just panicked.

Anyway, I am bringing the car in to have the oil changed tomorrow and they said they would take a look and see if anything is amiss.

Thanks again for the information, this site has once again proven to be a lifesaver.

[ghostofjk]

<div class='quotetop'>QUOTE(efusco @ May 12 2006, 06:51 PM) [snapback]254483[/snapback]</div>

It is right. There is no reason it should/would "charge up" the HV battery. The ICE will run briefly to reestablish a reasonable SOC (1-2 bars) then shut off again in anticipation that you will start driving again soon. At that point it will engage its normal algorythms and get the SOC back up in the 4-6 bar range.

Don't get caught in the trap of thinking that the battery 'needs' to be at a certain SOC.

Your car is working fine. My suggestion to you is to avoid situations where you're just sitting with the car in READY mode and not moving or going anywhere.
Sorry, I think you're mistaken. If it only stayed at 2 bars even with normal driving I might agree, but he's talking about when the car is sitting going nowhere. The battery will, in those cases, drain down to 1-2 bars and go through the very brief ICE run, then shut down sequences until you get moving again and the SOC will not often go above 2 bars...I've rarely seen 3 in those occasions, but usually just 1-2.
[/b]

I've had four Priuses and have driven a total of about 125K mi. in them. I've never seen a SOC under 3 bars, under any conditions. In fact, I think I remember Graham or someone saying the system would not allow the SOC to go below 3-4 bars, with the possible exception of limping toward a gas station having run out of gas. I suppose in an extreme case (AC on, gridlock) I can imagine it GOING down to 2 bars, but I can't imagine that not causing the ICE to cycle on. And I've been stuck in gridlock with the AC on several times.