Planetary coupled diesel electric hybrid

[glfporsche]

I am tasked with desiging a test setup consisting of a 200 kw diesel engine, and a 90 kw (continuious) electric motor coupled through a planetary gear set.

The diesel will drive the ring, the motor will drive the sun, and the output will be taken off the carrier.

My concern is with the planet set:

1. Can it take speeds and torques?
2. How should it be lubricated?
3. How should it be supported?
4. How should it be sized?

One option is to use an existing planet set out of a large Allison automatic transmission and modify it to suit our needs, the other is to design and build one our selves.

Are there any resources available, specific to planet gear design?

 

[mloew]

How about the Epicyclic Gear Train page at Efunda.com(

http://www.efunda.com):

http://www.efunda.com/DesignStandards/gears/gears_epicyclic.cfm

Best regards,

Matthew Ian Loew
"Luck is the residue of design."
Branch Rickey

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[EdDanzer]

There are many manufactures of planetary reducers. Fairfield Manufacturing is one. It would be wise to purchase this rather then design to reduce cost. You didn’t state a reduction ratio, but commercially available units may not suit your needs.
There is software to do gear design, but the learning curve and cost make in unattractive to all but gear manufactures.
If it is a test setup, and the reduction ratios are not too large, a belt drive would be less expensive to use. The disadvantages are belt tension side load, and shaft center distances.

 

[amorrison]

Surely hybrid manufacturers have already developed test units for their systems.

Googling using "diesel electric hybrid bus" got lots of hits.

There are probably research papers on these test systems also (ASME ?).

 

[glfporsche]

The planetary gear is NOT being used as a speed reducer. It is being used as means to combine the two inputs of the engine and the motor. The ring and the sun are the two inputs for the engine and motor respectivly, and the carrier is the output into the transmission.

We are not developing a test unit for a system, we are developing THE system, and then testing it.

I am looking for information specfic to either; 1. planetary gear design. or 2. a good source for off the shelf planetary gear sets.

I can't use belts or chains any more than I can PUSH a car up a hill with a rope.

 

[Metalguy]

The first time you try to run both engine and motor you may get the surprise of your life! Depending on the actual gear ratios and RPM/torques, you may find that diesel ends up spinning the motor backwards, regardless of whether or not its plugged in.

 

[glfporsche]

It won't be a surprise, we are absoulutly counting on it!

 

[HarrisDE]

I understand what you are doing. As a warning, I seem to remember a Borg Warner patent protecting this very idea.

You may look into using in-production automatic transmission carriers that can be purchased from any auto dealer. For prototyping I think this is the only cost effective way to prove out an idea.

Off the cuff I would say that any of the larger rear wheel drive carriers should easily handle your torque and splash feed ATF is sufficient (at low speeds).

 

[EdDanzer]

Glfporsche,
You will get reduction between the three parts of a planetary drive. The Machinery’s Handbook has some information about ratios and direction of rotation. As to off shelf gearing, the best you can hope for is transmission or final drive parts from commercially built equipment. Back in the 1980’s we spent some time trying to build a steering differential for a tracked vehicle from these parts and found it not possible, wrong ratios, or incompatible gear teeth. In 2000 we spent some time looking at planetary drive again for a different application and found nothing different. If you contact people who make planetary final drives for construction equipment, they might be able to help you with design and manufacture.
If you are trying to have the armature concentric to the diesel motor shaft, the electrical components will have to be sealed from any oil in the gear train.
If you want to declutch the armature, this design will require even more work. You may be able to use clutch packs from power shift transmissions, but finding design information is difficult.

 

[GraviMan]

You might like to try Webster for such a specialised gear box design - can't think of a contact off hand. They specialise in small volume designs, deal much in epicyclics, and have a good range of off the sheft bits. My guess is that if you are asking these sorts of questions you're better of outsourcing the design.

I assume you are replacing a conventional auto transmission with a hybrid system? What motor technology are you using out of interest? Must be pretty chunky, acting as generator and motor. Will torque equal engine torque or are you using a several epicyclic stages and auto box style brakes?

I have wondered for yonks about combining auto boxes and motors...

Mart