ICE Questions

Michigan's still cold, right? You've got the heat at 68... try
going to the climate screen and hitting fan "OFF", then see if
anything's different.
.
_H*

 

<div class='quotetop'>QUOTE(efrench515 @ Apr 4 2006, 03:36 PM) [snapback]234944[/snapback]</div>

I generally have my AC on pretty cold and don't have any problems on Auto A/C, I get up to about 30-40 MPH, depending on flat roads without the ICE kicking on and I was running down a long hill at 75+ MPH without the ICE Running at all. The Idle is also the smoothest I have ever seen in any care.

 

Once the engine is completely warmed up, if you drive relatively gently, the engine should shut off a fair amount when conditions are as follows:

Speed under 42 mph.
Level or downhill road.
Accelerator pressed very gently (as when maintaining a steady speed).

If you accelerate hard, then brake, alternately, the engine will run more.

If it is very cold out and you have the heater on, it will take a long time to warm up enough. If you have a short commute, it may never warm up enough. I hardly ever saw electric mode in winter in Fargo, with my very short commute, though john1701a, who drove many miles in weather almost as cold in Minneapolis, saw electric mode a lot. His car had time to warm up.

My engine runs very smoothly. If your is running rough I'd take it in to the dealer to be checked. You say if it was a Civic you'd say a cylinder was missing. Maybe that's what's happening. Loose spark plug wire?

One difference: The engine rpm on the Prius is almost completely decoupled from wheel speed. When there is a high demand on the engine it may run fast at slow vehicle speed. This is normal and allows the Prius to be more efficient. So don't worry about apparent engine racing at slow speed (or high speed, for that matter).

 

<div class='quotetop'>QUOTE(efrench515 @ Apr 4 2006, 04:40 PM) [snapback]234967[/snapback]</div>

OK let us hone in a bit not cold by "northern" Michigan standards. 32 is cold and your baby is cold! Buy her a block heater. Tire pressure?? Consider a radiator blocker, of course my solution is the very best, even natty, but there are a number of others. I lived in lower, like way lower, Michigan for 4 years and I have no knowledge of cold. You could really spiff up your numbers if you want to! First the radiator blocker then the block heater. Mobile one minor. Tire pressure major. After that technique and the sky is the limit!! I my hart I wish I had a bit of the snow you got this year. The only really bad thing about the climate in the PNW is that I miss winter. I however do not in any way miss a Midwest summer!

 

I would guess and as it's a 2k6 and you can't get a CAN-view for it to check, that the HV battery is still to cold to have the HV (hybrid vehicle) computer let it go into stealth. If you park outside and let it sit over night at freezing that the battery never gets warm enought to allow it to stealth with your short commute. As for the low fuel mileage there could be several reasons for it but a block heater would help. You would have to weigh the $ for electricity vs. gasoline but I would suspect that it'd pay back in a year or two, less if you can do the install yourself.

 

<div class='quotetop'>QUOTE(Frank Hudon @ Apr 4 2006, 07:41 PM) [snapback]235044[/snapback]</div>

Listen to Frank!

 

<div class='quotetop'>QUOTE(efrench515 @ Apr 4 2006, 08:40 PM) [snapback]234967[/snapback]</div>

I am from NE Wisconsin. At temps above 25 deg. F I do not use my heater - unless the windows fog. Then I operate W/S heat long enough to clear the screen. Turning off the w/s heat leaves the A/C AUTO lite illuminated, so I turn the A/C off simultaneously.

When I operate that way the engine warms up relatively quickly and will soon shutoff after the vehicle is braked to a stop.

I too notice a roughness in the engine - but, only when it is coming to a complete shutdown. Toyota's design ensures the the engine comes to a stopped position (crankshaft) so that subsequent restarting will be quick and efficient. Sometimes there's no noticable effect, and other times the engine seems to be shaking like a wet junkyard dog, but only very briefly, as the crank is being moved to the ready position.

I've averaged (Dec-to-Mar) 40.3 MPG. Jan was unusually warm, but then Dec was unusually cold.

 

<div class='quotetop'>QUOTE(Frank Hudon @ Apr 4 2006, 10:41 PM) [snapback]235044[/snapback]</div>

I think you are all missing the point. When it's cold, the ICE will run much more frequently to keep the catalytic converter at its high operating temperature. Toyota’s priorities are to lower emissions, and then superb gas mileage. Using your heater has practically zip to do with how much the ICE runs.

 

"Using your heater has practically zip to do with how much the ICE runs."

In my 40,000 mile experience I've been able to turn the engine on/off by turning the heater on/off.

If the SOC of the big battery is too high, the engine will be turned by the smaller electric motor, thus draining a little charge from the big battery, and appearing (feeling) like the engine is misfiring. In all I've read, this is normal and no gasoline is being burned.

 

<div class='quotetop'>QUOTE(Frank Hudon @ Apr 4 2006, 06:41 PM) [snapback]235044[/snapback]</div>

Ah, yes! The battery temperature!

Given the relatively short length of your commute, I think your mpg is in the ballpark.

One thing to note: With an EV switch, you can force the car into EV mode (providing your speed is under 34 mph) sooner than the car will go into electric mode on its own. This will allow you to draw off some of that charge when the battery icon turns green, improving your mileage a bit. But this only works below 34 mph because that's the upper limit for EV mode. (By contrast, the car will stay in electric mode, if it initiated it itself, up to 42 mph.)


<div class='quotetop'>QUOTE(itstwowords @ Apr 5 2006, 02:34 AM) [snapback]235191[/snapback]</div>

This is absoluetly wrong!!! While the car does indeed need to keep the cat warm, and will run the engine to do so, the engine will run almost continuously if the heater is on and the cabin is much colder than the set temperature. Like Finman, I too can turn the engine on and off by turning the heater on and off, during a fairly lengthy period between the initial warm-up and when the cabin has fully warmed up. In Fargo, in winter, this was my entire commute.

 

Lots of opinions here. I operate by the set it and forget it standard. I also consider that in order for the battery to be operaing efficiently the cabin has to be at a comfortable temp for you. The battery uses cabin air to control its own temperature.

I wish I could convince you that 1. 32 is cold by the car's standards, and 2. you can toggle the engine from running or not running with the auto A/C button, however that prevents the cabing from attaining a comfortable temp in a short period of time. FE on the Prius doesn't get really great until you get up past about 50 degrees ambient outside temp. And then it improves markedly as you get closer and closer to 80 degrees outside.

Make your cold weather heating setpoint about 68 and forget it. Most of us can't outthink the car in terms of efficiency and the car is taking into consideration factors that we often times ignore or are unaware of, specifically in this instance ambient temperature for the battery and its most efficient operating point.

The onboard computers are taking into consideration hundreds if not thousands of different states in the vehicle and then optimizing performance for those conditions. As those conditions change the vehicle adjusts to meet those needs. The vehicle is always looking to operate as efficiently as possible when certain operating conditions are met.

As for engine roughness, I cannot compare yours to mine so I cannot give a good answer about your observation. I think you are still suffering from cold weather. The engine will exhibit much more shudder when it shuts off during the winter, or when the weather is cold and the engine is coming up to temp. No engine will run smoothly when cold, especially when the fuel control system is having to adjust mixture for weather conditions which are not good for overall vehicle efficiency.

And one last word about cold weather FE. You may think yours is bad, however everyone else who is driving anything buy a hybrid is doing much worse.

 

Just to add my 2 cents:
My commute is 48 mi along the foothills of the Rockies. I keep my car garaged.
This winter I got an average of 43mpg with the heater on the whole way when the outside temp was between -10 and +15. I didn't see mpg above 25 untill I had driven for 15 min or so.

Once it warmed up a bit to 20's an 30's, my average improved to 48 or so. heater on 70%.

Now that the temps are in the 60's I'm getting around 54 to 55 mpg on average.

Because many things effect your mpg, there is no one answer to poor mpg. In no special order, some are;

Engine/Cat/Batt temp
Cabin heater or A/C use
Tire pressure
Driving habits
Road conditions (that affect the rolling resistance of the tires, like rain or snow pack)
Road terrain (hills, curves, etc)
Stop and go traffic
Speed
The 1k and 10k mile mpg boosts from engin break in
Passenger/cargo weight

 

OK, I'm only on my second tank of gas, so I'm not an expert.

But here's what I've experienced....

I have a 3.5 mile commute. Takes about 10 minutes. My ICE hardly ever shuts off if the outside temp is below 50 deg. If I go for a 15+ minute drive it shuts down more often. The longer the drive and the warmer the engine and outside temp, then the more it shuts off.

Ditto except from a dead stop. Warmer and longer drives = more battery. The other day, it was about 75 deg and I'd been driving for 20+ minutes. I got up to about 45 mph only on battery with a very light touch on the "gas" pedal.

Mine runs VERY rough on some days too. It doesn't seem temperature dependent. Today was about 65 deg and at a stop light one block away from my parking lot, the car bucked and jerked while the ICE shut down. It was so bad that it lurched forward with my foot seriously on the brake and with the car at a dead stop. It is particularly noticeable when the engine is cold. The rough running is almost always when coming to a stop or when the ICE shuts down at a light. No rough running while in motion over 5mph.

My first tank I averaged 42mpg. I'm almost at the end of my second tank. It started out VERY badly, I quickly went down to 36. Now I'm back up to 40. I attribute this to two things: 1) I wasn't driving "nice". 2) The outside temp went from 50's to 30's and now back to 50's+. My mpg followed the outside temp.

 

Just had a thought: When you say your engine runs rough, do you mean steadily? Or do you mean an occasional shudder? During the first 5 or 10 minutes of driving, when the engine is still cold (maybe longer in very cold ambient temps) the engine will shudder as it shuts off, or even as it starts. This is perfectly normal. But if you mean it is always running rough, I'd have it checked.

The car may be sending some cabin heat to the battery compartment, but it is NOT principally cabin heat that warms up the battery: it is the battery's own internal resistance. This can be seen if you monitor the battery temperature: it rises as you drive the car, whether you are using the heater or not.