viajero

Not with the power split device. It's not really a transmission, continuous or otherwise. No gear ratios ever change. As larryh has observed, whether in D, N, or even R the mechanical connections are the same. All the "shift lever" does is tell the computer what the driver wants to do. The computer then decides how much electrical load or power to apply to the motor/generators to make that happen. The MG2 can spin backwards to make the car go backwards, but the connection between the motor and the wheels is always the same. This has been linked a few times before, but a good animation to play around with and see how it works. http://eahart.com/prius/psd/

I've never seen mpg that low, unless going uphill and/or in a strong wind. I usually get mid 30s at 75 mph. Make sure to measure mpg on a round trip where you come back to the same starting point where you reset the trip meter. Even a seemingly small uphill can make a big difference in miles per gallon. Also check the SOC when you start and finish. Sometimes EV Later likes to add a bit of charge from where it starts, which will affect your mpg.

In my C-Max Energi, the ICE turns on and off during highway driving on flat ground up to speeds in the mid 60s. At 70 mph or more, the ICE just runs continuously, with a very slight charge or discharge from time to time, just as you described. My theory is that at this speed the engine is operating near its most efficient operating point, and there's nothing to be gained by using the hybrid system. Google "Brake Specific Fuel Consumption" (BSFC).

That's my understanding. Spinning the generator (MG1) and motor (MG2) in opposite directions at the same speed is what effectively "disengages" the ICE. The ICE can stay connected to the planet carrier and not turn or feel any (or at least not very much) torque. The trick to the whole thing is the computer adjusting the MG1 to take up the slack in rpm between the wheels and the ICE. That's how it emulates a CVT - you can run the ICE at any speed relative to the wheels. By either applying an electrical load to or forcing electrical power into the MG1, the computer can also make up the difference in torque between the traction motor (MG2) and the ICE, as well as the rpm. It can make the MG1 be a drag or a boost as necessary. Seeing that Prius animation years ago helped to sell me on a Ford Energi. I love that system; it's so simple and elegant mechanically. Of course the complexity is in the software which has to decide when to feed how much electrical power into or out of MG1 and MG2 to keep the whole thing turning smoothly.

The regen produces more power than the car's background usage, but its efficiency is less than 100%, so you get less energy when coasting to a stop on a level grade than it took to accelerate you up to speed from a stop. Otherwise we'd have a perpetual motion machine and we'd be rich! :) For an example with some made-up numbers, it might take 400 Watt-hours (0.4 kWh) to accelerate from 0 to 60. Then if you immediately let off the gas and coast to a stop, you only get 300 Watt-hours added to your battery because some energy is lost in the mechanical-electrical conversion and some in charging the battery. Then when you accelerate again you only get 270 Watt-hours out of the battery because its discharge isn't 100% efficient either. So, either the ICE has to start and add another 130 Wh, or your battery ends up 130 Wh lower than at the start of the coast. The good thing is that regen has saved you the 270 Wh that would otherwise have been lost to heating the brake pads, so the ICE only has to put in 130 into your next acceleration instead of 400.

This exact same thing happens to me when I start the car in L gear with a full charge. Others on the C-Max forum have seen it, too. Even if I'm accelerating away from the charger, the engine will rev wildly. If I start in D and don't shift to L until I get below 97% charge (on the Scangauge) this doesn't happen.

I like your graphs. Checking your numbers by comparing your end results to some researched numbers, it looks like your assumptions are pretty good. The FFE is rated at 43 mpg combined and 100 mpge, or 2.32 times more efficient using electricity. I think the EPA uses electrical energy from the wall, so allowing for 80% round trip charging efficiency, 100 mpge would be 125 mpge from the battery, or 2.91 times more than 43 mpg. That's awfully close to your 2.9. Looking at this web site with some BSFC graphs people have scrounged up, most gasoline engines can achieve between 215-250 g/kWh at their sweet spot. http://ecomodder.com/wiki/index.php/Brake_Specific_Fuel_Consumption_%28BSFC%29_Maps This Wikipedia article got some data from an SAE paper I'm not going to pay for, but they say the 2nd generation Prius engine, which should be similar to the Energi's Atkinson cycle 4-cylinder, does 225 g/kWh, for a peak efficiency of 37%. http://en.wikipedia.org/wiki/Brake_specific_fuel_consumption Of course they can't keep the ICE right at the sweet spot all the time, so average efficiency is lower.

Everything you have said is not true for me. In D I always have regen coasting. In L I always have even more regen coasting. The only exception is if the battery is full, in which case the ICE will do compression braking in L. In an earlier post you said that the car's onboard systems use more power than regen can provide. That is also not true. When coasting to a stop my battery SOC increases. Going down a big mountain I can fill up more than half an empty battery. If your Energi is behaving as you described, something is very wrong with it, and you should take it in.

Yes, heat. All the potential energy lost to going downhill, or kinetic energy lost to slowing down, ends up as heat if the battery can't store it. If using engine braking, the compression of the air in the cylinders heats up the engine block and the heat is dissipated through the radiator just like the heat from burning gas when driving. If using friction brakes, the brake discs and pads heat up and dissipate that heat into the air.

Even a little incline makes a big difference. To get a valid mpg number for the gas engine, you need to make a round trip so all the ups and downs even out.

On another thread someone made a handy observation which should have been obvious but I hadn't figured it out after driving the car for a year - the messages on the dashboard are color coded. Red for error, yellow for warning, and white for information. White is just an FYI, and nothing is broken when you get a white message.

They previously announced MFM used AT&T. This press release specifically mentioned Focus Electric, but it's pretty unlikely they'd use a different carrier for the Fusion and C-Max which were released about the same time. http://www.att.com/gen/press-room?pid=19386&cdvn=news&newsarticleid=31711&mapcode=

Around Austin I see this less than 10% of the time. And it always tends to be at certain places. Some spots I've never seen an ICE car there and others about half the time. It doesn't seem to correlate to how crowded the lot is, either.

The Energi battery is much smaller than the Focus. It might overheat if charged faster.