I posted this in the fuel economy forum but figured I'd post it here too. I drive a non-NAV version so I only have the watered down consumption display. I accelerate to just above 40 mph, let my foot off the gas and the ICE shuts down. I then try to glide to about 30 mph before doing the same.

1. If I'm doing the glide portion correctly how far on level roads should I be able to glide before having to accelerate again. I'm guessing that I'm getting about 1/4 to 1/2 mile.
2. I'm able to get it to glide fairly well below 35 mph. However when I first let off the gas the arrow will show regen. I then give it a little gas and the arrow will change direction showing EV mode. This will continue until about 35 mph, no matter how finely I control the gas pedal. I can't seem to get the arrow between battery and wheels to disappear until I'm close to 35 mph. Any suggestions.?

 

If I'm doing the glide portion correctly how far on level roads should I be able to glide before having to accelerate again. I'm guessing that I'm getting about 1/4 to 1/2 mile.
On level I would think that slight throttle pressure under 40 mph will keep you in the E mode until the battery discharges enough to make the ICE on. That could be several miles if it is indeed level.

In Nags Head I was doing a lot of gliding and averaging 45 mpg over a 300 mile drive over the couple of days there. The only time my ICE was on was to start out from a stop and when the battery got low.

 

That I can do, but if I'm not mistaken the idea of gliding is to drive with neither the batteries nor ICE driving the wheels, nor regen going on. In essense you're coasting with no power transfer and no drag from the electric motors. You'll have to use the ICE sooner than with EV mode, but since the battery is not being discharged then the ICE only stays on long enough to bring the car back to speed. The reason for not allowing regen is to avoid allowing the motor to slow down the car.

 

but if I'm not mistaken the idea of gliding is to drive with neither the batteries nor ICE driving the wheels, nor regen going on.

3 Comments:

1) Only on brief occasions have I seen the energy screen go blank (gliding?) where no ICE, no Battery AND no regen. Personally if the car is not accelerating I want it to regen. In this method of gliding you will constantly be speeding up and down and not maintaining speed. The car will slow down. A 3600# mass will slow down no matter how pumped the tires are. If this is "true gliding" then I don't practice it and I don't think it's actually possible for more than a second or so (at least keeping regen from occuring).

2) In the process of (let's call it) "assisted gliding" I believe this is all that is possible unless you're on full E mode, I speed up to or above speed, let off the throttle to either kill the ICE or drop it to the 60 FE mark and then gently apply the throttle to maintain speed or allow gentle but reasonable deacceleration. I get full benefit of battery usage with minimal ICE involvement. In this case the electric 40hp is adequate to maintain speed. As I slow or approach a hill the ICE will kick in (under 42) or gently assist, then as I level off or go down a grade the ICE backs off to stand by operation. I assume this is what you've practiced as well as most others. If it's not gliding, then I'm suggesting it's the only reasonable method of driving the TCH to maximize fuel effeciency.

3) What's the point of NOT using the batteries. In my 15 mile loop, I had stop signs, 25 mph, 35 mph, 45 mph and 55 mph limits. I had flat city streets and rolling rural roads. I watched the energy screen to see the effect on the battery. Only once did it get down to violet, and that was in town running on E mode. When I was doing that I was not getting my best milage of the loop as the ICE would kick on to charge the battery. Slow driving on E feels great, but you're not covering a lot of miles which in turn has little impact on overall tank FE unless that's all you're driving in. When I hit the rural roads, non stop, steady speeds, I was able to let my milage climb (to the above 50 range). It was interesting as I watched the gage drop up hills and rise on down hills, but the battery never got below 3 blue bars, and never got into the green (most of the time it will for me). The computer did an excellent job of keeping an adequate charge to assist when needed and I did the rest by practicing "gliding" when possible.

 

When I first found this board I found a link to an article on pulse and glide. It was written with the Prius in mind. It specifically stated gliding was the state where there were no arrows.

You didn't want the arrow from the wheels to the battery because the drag of the motor would slow you down quicker. Aside from which if you start pulse and glide with a high SOC then you don't need the regen.

You didn't want the arrows from the battery to the wheels because although you can go for a while using EV mode this would discharge the batteries and eventually cause the ICE to run to recharge them.

The idea behind pulse and glide is that there is no (or minimal) energy transfer between wheels and battery. The ICE only runs for about 4 seconds to increase your speed from 30 to 42 and then you glide for a while with the ICE off. If you can go 1/3 mile (just a guess) on glide you're only using about 12 seconds worth of gasoline to power the engine for each mile.

WVGasGuy, I appreciate your answers. I also have not been able to get all the arrows to stay off for more than a few seconds at a time. Because of this I have to look at the display so much that I don't think it's very safe. Since the ICE is off regardless of whether or not there is electrical power transfer you can't use your ears to tell whether your gliding. I was just posting this question because I couldn't get the car to do a long sustanined glide and was wondering if anyone else had.

 

This is a very interesting discussion you guys are having. These are the kinds of questions we can explore as a group. I'm looking forward to contributing, if my car ever comes.

 

I remember reading a lot about pulse and glide before my TCH arrived and was eager to try. But now I've pretty much written that off as a good strategy for the TCH in my case. I'm not at all concerned about using the battery up, in fact everytime I see the battery is providing power, with or without the ICE I feel mission accomplished. In my driving conditions, it is so rare for the battery charge to fall more than 3 bars from the top. The only time I've ever seen it get low enough to force an ICE start was in a long drive-thru at a coffee shop with the A/C running. Using the battery to max potential rather than avoiding it thru gliding is my goal. There are too many ICE required situations and regen opportunities for me to worry about pushing the battery too low.

 

My problem with pulse and glide is the traffic I have to keep in mind as I do this, and the highway speeds I go at make it difficult to stay legal and at the same time maintain speed with traffic. Thus I use the cruise control. A lot less work.

 

Any time the TCH is moving forward there are 6 modes of operation; 1. ICE, 2. EM, 3. Regen, 4. EM & ICE, 5. ICE & Regen, & 6. ICE, EM, & Regen. The time that you see no arrows on the display is called "deadband". This is a very short period of time during which the system is trying to determine the correct mode of operation for the system at this time. This "deadband" period is to prevent the system from rapidly switching been modes which could be damaging to the overall system.

 

There is an article about a competition in which some people, including one from this board, drove a Prius and averaged 109 mpg. This was over a full tank of gas, so it wasn't on a short trip going downhill with a tail wind. They did this explicitly using the pulse and glide method in which they described it as "no power transfer". I will have to try and find it and post the link.

Regarding your modes I don't understand several:

Number four - EV is defined as driving on electric power only (Electric Vehicle), so EV & ICE are mutually exclusive.

Number six - Same reason as above, but also regen only occurs when coasting or braking. EV and regen are also mutually exclusive.