Thanks Gary, I forgot about that change with model year. I like the feel of the heavy regen in L.

I had my brake pads checked recently and at 63k miles the pads are down by 10%, I think largely due to my avoiding mechanical braking whenever possible.

 

As Gary reminds us, the '08 is different from the '09. Having the '09, my explanation and understanding of what's going on applies to it. When I use the phrase "shut off", I mean the gas engine is not running. I do not mean that I've actually turned the ignition key off.

There are four situations that need to be described:

Shifting into "L" is different if the '09 is above or below the maximum speed for ev-only operation. That limit is 63kph, or about 40mph.

Below that speed, and for the purpose of the discussion, reducing speed can be done by using the brake pedal or shifting into "L". Using just the brake pedal, and nothing special going on (like a panic stop, and above 3mph), all braking is done with the regeneration system. The engine (given it has no reason to be running such as warming up or a/c full on) will be shut off.

If, below the ev speed limit, you reduce speed by shifting into "L", and given all the caveats mentioned above etc., the engine will start up. Although it won't be using any gas, it takes some energy for all those mechanical parts to be moving around. This absorbs energy and so there will not be as much left over to send to the hybrid battery.

Now, turning to reducing speed above the ev maximum speed. Whatever else is going on, such as a/c on or off, the engine will be running above that speed. When you're coasting, it isn't consuming gas, but again having all those parts moving around requires energy that isn't going to the hybrid battery. If you use the brakes, the engine will keep turning over, at an rpm that's higher the faster you're going. Applying the brakes won't change the rpm. You'll get regeneration from using the brake pedal, but very little from the engine.

If, instead, above the ev speed limit, you shift to "L" to reduce speed, everything is the same except the engine turns over at a higher rpm. This is how the '09 simulates the engine braking of a non-hybrid. The higher the rpm, the more energy is wasted moving engine parts. I think this is why the hypermilers shift into N in this situation. So to maximize the energy available to the hybrid battery, you want to lower engine rpm, which is "D" instead of "L".

Taking these ideas on the road, I regularly drive roads with such long steepish climbs that on the way down, the hybrid battery gets filled up and I have to keep the speed under control using the brakes and/or shifting into "L".

I can compare at what point during the descents the charge gauge shows that regeneration has ended. At those points, the speed starts to build and I have to use the brakes and, if I'm not already in "L", then also shift into "L" to regulate the speed.

If I have been using "L" from the start of the descent, the point where regeneration ends is lower on the hill. This means there has been less energy being put back into the hybrid battery. It also means I have to use the mechanical brakes less, which is a good thing. Actually, I never come down the hill in "D" because the speed gets out of control right away, and using the brake pedal means I lose regeneration fairly quickly because the battery reaches capacity sooner.

I used to use "L" often to reduce speed, because I was still thinking like a non-hybrid driver. Using the transmission puts more load on the transmission and less on the brakes, and some say: "transmissions are cheaper than brakes". It's also a sign of driver skill to slow without using the brakes, as shown by slowing without the brake lights lit up. However, the hybrid is the opposite of that, and by stopping using "L", I have upped the mileage a notch.

On occasion, below the ev speed with the engine shut off, applying the brakes will cause the engine to start up. I don't know why this happens, but it's pretty rare.

Lately I've tried using the a/c to see what effect it has on the descent. I thought perhaps the FEH would just run the engine more or harder to run the a/c. In fact, doing the descent with a/c turned on, and in "L", I can get farthest down the descent without needing to use the mechanical brakes. Maybe I should try it with all the lights on and blowing the horn:-)

Now, few people with FEH's live in places where the hills are so large they will exceed the hybrid battery capacity. What matters is that it's a convenient way to test what operating mode enhances regeneration.

 

The OP has an 06 and you quoted his post. Your suggestion of not using low is at best confusing since that is a viable strategy for his/her model year.

 

Ok, I'd be very interested to know how the pre-'09's behave in the four situations in question: above and below the top speed for ev operation, and reducing speed by using the brake pedal or shifting into "L".

 

Pre-'09's can use L to separate regen from the friction brakes at any speed. For instance, coming off the highway at 70mph, I just time L to reduce my speed. You can slow down to 6mph without using the brake pedal. Below 6mph, regen is cancelled and you are using the brake pads to stop.

Programming changed in the '09 and newer Ford Hybrids where you must use the brake pedal and judge the point between using the friction brakes and regen.

Ford went back to the old way of L programming in the '13 Energi. Ford added a new mode for downhills by controlling regen to maintain your speed. For instance, if the speed limit is 35mph, you can change to this mode at 35mph, and the computer will regulate the speed by using regen on the downhill when required.

Just be aware that programming changes all the time in Ford Hybrids, so be careful giving advise.

Gary

 

I also use "L" frequently in my 06 when I'm in stop and go rush hour traffic.

Was unaware of the 8 mph thing....good to know.

 

Would it be fair to say you had no problems with the other content of my post?

 

Rather than further derail this topic, I'll start a new one on this subject.

 

I have been doing pretty well with it so far getting 34.1 MPG over the past 2 weeks and about the only thing I have done differently than my Jeep is I have not used A/C much at all, but it was pretty limited in my Jeep too

 

My oil was filled above the Max line. I took out about half a quart, and it's between the lines now and the car seems to be getting better mileage. This also jives with what I believe to be true about the oil - that my FEH has a 4.5 qt capacity and most cars use 5 qts...maybe?

Also noticed that my mileage ended up being 24.6 - not too bad afterall, especially since I was figuring something was wrong and I'd be down at 17-20 mpg. Turns out, my guage may be a little off, or perhaps I just need some time to learn how it works. It was showing half empty and I only put in 5.6 gallons. I was expecting 7.5, or so, for half of a 15 gallon tank.

The Escape seems to be on a better track, having removed some oil.