I've seen some reports say the generator size is about 43HP, but other information says the traction motor is also the generator, so same size of 70kW (93HP).

So what is the re-gen generator size? Also is it a DC or AC, if it is AC it should be synchrounous instead of induction...

 

There are two AC motor/generators in the eCVT

36 kW Permanent Magnet AC Generator Motor
65 kW Permanent Magnet AC Traction Motor

They both can operate as a electric motor or a generator and are referred to as MG1 and MG2. MG1 is also the engine starter motor and MG2 is is also referred to as the traction motor connected directly to the drive wheels. MG1 is also called the small generator and supplies power to MG2 and charges the battery. MG2 is the regen motor that take energy from the wheels to also charge the battery. There is no reverse gear in the eCVT but MG2 operates in the reverse direction to drive the vehicle backwards.

GaryG

 

Thanks Gary.

For starting, there are actually two kinds of starting. Cold start and Hot Start. For example, in the morning you put key in and start the SUV, that is cold start. But during the driving if you step gas pedal very hard, the gas engine will be started from EV mode, that is hot start.

When you say MG1 is the engine starter, do you mean the cold hot or both?

Also for a 2008 Escape Hybrid, the published motor size is 70kW, does the motor size changed? So both MG1 and MG2 can take the braking kinetic energy?

 

The engine can only be started with MG1 no mater if is a cold start or hot start. Ford has a Cold Start Strategy programmed in the PCM which retards the ignition spark to heat up the engine quicker. You will notice the engine will idle and the electric motors will provide acceleration during this Strategy. This was done to reduce emissions from a cold engine. If the engine is keyed off for over ~5 minutes, this Strategy will be repeated each time no matter how hot the engine already is. The HV battery is allowed to drop below its lower limits of 40% to as much as 32% during the Warm-up Strategy. The battery will take more time to reach the ~42% required to go EV again so fuel efficiency is reduced during the Warn-up Strategy.

The motor size is always the same, 36KW is rounded up to 40KW and 65KW is rounded up to 70kw in some articles. Kinetic energy comes from the wheels during deceleration and braking which only turns the directy connected MG2. I have not read that MG1 also provides kinetic energy.

Here is one article that refers to 36KW and 65KW:
http://www.motorcraftservice.com/vdi...DSM500_HEV.pdf

GaryG

 

Thank you Gary. That is a great detailed PDF file.

The system works more complicated than I thought. The small 36kW generator is powered by engine to charge the battery, and only operates in generator mode, but the 65kW operates in both modes, I thought the smaller one were to be powered by braking energy.

And I found out all two electric machines are AC instead of DC, I would think they are synchronous AC instead of induction AC. In that case there should be also rectifier system, SFC(static frequency converter) system since NiH battery is DC, it is very complicated, more than GM Volt....

 

Your welcome

MG1 means Motor/Generator 1 just like MG2 and not only is a engine generator, but can also drive the wheels through the planetary gears in EV. Yes, they both are synchronous and the system is very complicated to figure out.

It sounds like you want to learn more about the EV system like many of us did and continue to do with any changes. The '05 FWD FEH I still own had become a hobby to increase MPG and share my experiences here and other forums. The Big changes in my '09 FWD FEHL drivetrain and new Variable Voltage Converter (VVC) has created a new interest for me to figure out. This is the new technology Ford is using in the prototype FEH Plug-In models being tested today.

Here are some other good information on the FEH/MMH:
http://www.gulfcoastnews.com/RT2005FordEscapeHybrid.htm

http://deepblue.lib.umich.edu/bitstr...jinmingl_1.pdf

http://alexandria.tue.nl/extra2/200142094.pdf
http://www.ece.eng.wayne.edu/~hying/...ogy%202006.pdf

http://uvic.commonenergy.org/w/image...!IDETC2007.pdf

Read which ones you like.

GaryG

 

Wow, you really have great information!

I am an electrical power engineer and very interested in the system design and operation of Ford Escape Hybrid. I am impressed by the 2nd link, in the end of the book he calculated all the different sizes of MG1 and MG2 for fuel consumption. So Escape Hybrid had been carefully sized to maximimze the fuel efficiency....thanks!