Best Driving strategy?

What's it called when you maintain a relatively constant speed for a a mile or two and the ICE is off? I thought that was gliding.

 

I think that would require a complete redesign of the system. My limited understanding is that you can't run "electric only" at speeds much greater than 45 mph or so because it would overspeed MG1. I beleive MG1 and the ICE turn in the same direction so their speeds add in the planetary gear set. The ICE starts so it's speed will add to that of MG1 and prevent it from going too fast.

Please correct me if I am wrong.

 

In the Yahoo groups it was usually called "stealth mode", although I haven't seen that term so much recently

 

I believe on the Classic (00-03) Prius you CAN run on electric at higher speeds, although above 42 mph the ICE is turning (as you say to protect the MG) but not burning petrol (gas). I thought this was true of the 04+ model too.

Regards

PeteB - 02 Silver 'Classic' - 71k miles
Luton UK
Life mpg 51.41 ~ 42.81 ~ 5.49 ~ 18.20
(UK ~ US gal ~ I/100Km ~ Km/I)

 

That is how it works and you can see it if you have a scanner of some sort. Over 42 the ICE runs all be it at low to moderate RPMs. You will see on the MFD with the same light pressure on the accelerator that you use to glide at low speed 99.9 MPG or some lesser number. This of course discounts any changes in incline.

 

Other than occasional manual EV mode, I use the Nike Driving Method:

JUST DRIVE IT!

 

Windstrings,

I agree with some of what you are saying. I manipulate the car all the time a bit like you describe and it does boost my mpg.

I think you need to consider what you are doing from a different perspective though, and do what makes logical sense on it's own. Don't just try to make the battery stay low or high. Ultimately the car will resist you on that and you'll lose.

But there are situations where some of what you say makes sense. The Marathoners did talk about makiing sure the battery stayed high enough in their pulse and glide thing to cut down on unnecessary start and stop of engine.

And an extra low battery clearly is good if you are about to go down a mountain and want to have max room for the regen.

I also agree it would be nice to be able to go a bit faster for pulse and glide with engine off. The rpm limits are not a problem. I don't need a top speed over 90 mph and the Highlander hybrid has already proved they can design a generator that goes faster. I think being able to get to 50 before engine spins would be possible and reasonable. Maybe on the 2008?

For highway cruising I find little affects my mpg that I have control over. But for slow back roads going under 42 I generally maximize my engine off mode and that works great for me long as I don't hit too many lights wrong.

But I concentrate on a few other things too:

Run the engine going up most hills with some battery charging, if only to prevent a low battery at a traffic light, which would keep the car engine on. Also caused if it cools too much.

After that I try to maximize the distance I can go on battery power and keep the engine off. I especially try to prevent short start stop cycles that aren't needed.
And I help force battery mode mainly for down hill sections not steep enough to just coast on. By letting the battery charge on the uphill parts I can do all this and still the battery stays near it's normal set point. On level roads I find the car switches modes just fine by itself and I see no reason to force it except to feather when done accelearating so it knows I am ready for constant speed.

Finally I just use battery mode when needed for whenever torque needs are too low for efficient engine use and I can hold ht engine off without serious battery discharge. Traffic jams are a very effective use here which luckily for me are mostly on downhill sections.

If your battery goes too high the car may use electric mode in places where it shouldn't to dump charge. Such as driving up hill where engine could be more efficient.

Likewise if bettery is kept low, assuming you can do it, you won't have a reserve for accelerating when you need it, and there is the problem of power waste at traffic lights mentioned, or engine charging the batttery on a nice downhill stretch.

 

Is 40 MPH the definite cut-off? I'm almost positive I've coasted/glided/whatever the term is without the use of the ICE at speeds above 45 MPH.

 

I too have see brief gilding at 75 mph on a major down hill over the Rockies. The commuter does what it need to do. I have had momentary gilding over 42 but nothing I can do consistently.

 

what is ice?

 

can you direct me to a forum that teaches teriving techniques on optimizing milage. I just joined this chat (my first ever!) and I have my prius only 1 1/2 months. I am getting low 40's mpg around town and am quite disappointed; I was expecping around 50 mpg acfcording to the toyota dealer and "word on the stret" thank you

 

If the MFD is to be believed, I regularly enter into warp stealth as well as gliding at over 40+ mph.

Using stealth, the ICE appears to ALWAYS come on at about 40-45 mph. After that, conditions permitting, warp stealth is possible as is gliding. It's easier to do with a battery in the green, sometimes in the blue it appears that the car simply won't allow it; any throttle at all and the ICE comes on. Hilly terrain favors it also. I never thought I'd see it but even in cruise control I've seen both gliding and warp stealth.

Drive to maximize MPG, not to keep the battery full. Use the MFD for this.

OK, for normal driving to maximize MPG (no marathon, and others are on the road), drive as though you have an underpowered engine. Accelerate moderately going down hill to gain momentum if there is an uphill coming up. Then use that momentum to carry you, backing off on the throttle as needed to keep the mpg up and to stay in EV or gliding mode. It helps to not pay attention to the speed limit, you're on your own there. Easy here in Maine harder elsewhere. With practice and by looking ahead you can exactly balance the equation of losing the gained downhill momentum by climbing the hill, so that you have to add very little energy on the climb. Recently on a 100+ mile trip to the coast, on secondary roads, we averaged 58.9 mpg using that technique. Understand that your speed will fluctuate by quite a bit. Obviously you want to use regen braking as much as possible to keep the battery charged, not the engine.

FWIW, and this is really off the topic of the post, well, maybe not. We met 2 Prius owners a few weeks ago and asked them the question I'm pretty sure we all ask each other, "Do you like yours as much as we like ours?". It turned out that they weren't getting the mileage they thought they should, in the mid 40s was their average. It turns out they were using the "B" setting for braking down hills, at stop lights, etc.. The gent couldn't understand to leave "B" alone. Couldn't understand that if the engine is doing the braking, that kinetic energy lost that way isn't going to the battery and he didn't want to "wear out the brake linings" by feathering the brakes. Have no fear, after the battery is truly full, after the top bar has been lit for awhile and you're still charging, the car will automatically revert to "B" all by itself. You'll know when it happens, there will be no doubt about it. To stay out of "B" mode, if it's hot out, open the windows and turn the A/C to max, anything to drain the traction battery. This only needs to be done on long descents, like Mt Washington or something similar to keep regen braking active. Under those conditions you NEVER put into storage all the energy you put into the climb, the battery simply isn't big enough. You must squander juice to stay out of "B" mode. Only under the conditions of long or extreme descent use "B", you'll fill your battery anyway, other than that, forget it's there.

 

situations of maxing the charge on the traction battery is a pretty rare. i have seen all green several times for long periods of time on some pretty good hills and the only time i have ever seen the "overcharge" thing was the decent from Mt. Saint Helens. (this was after 20 miles of coasting in drive with occasional braking to regulate speed on corners)

 

I should have read your post further before posting, Evan.

I didn't know that about the ICE spinning.

Come to think of it, the MFD doesn't always tell when the ICE is running. I've heard it run simply for engine heat, without driving the vehicle.

 

i think the MFD isnt supposed to represent the ICE "spinning. it is an energy flow diagram. that is why it only has arrows going when there is gas flow. if no gas is being used, then no flow no matter what the speed. that would explain when stopped and the ICE is on to maintain charge and support other accessories