hybrid drive train - Transfer case backwards ok?

[ccanuk]

ok... I've been doing a lot of research on converting my XLT into a hybrid vehicle.

I'm favoring the gas powered (eventually convert to diesel), electric assist theory, and want to make the explorer AWD/4WD...

This is a pic of what I think I have and what I want to do.
http://ccanuk.brinkster.net/hybrid/hybrid.jpg

to accomplish the AWD/4WD I would first either convert to manual hubs and leave them locked all the time, or have them welded/replaced.

the second is to set up a second transfer case between the front diff and the original tcase, but backwards and always in 4wd mode, so that the input shaft is the output shaft and the two output shafts are input shafts. one input shaft for the original tcase for when I put the original in 4wd, and one for the electric assist motor

this way I could have AWD for normal driving, and when I need the extra traction I can put the original into 4wd, and the electric motor's power will be distributred throughout because the front and back will be locked together.

to recharge the electric assists powerpack I would either use a dual shaft motor and add a generator, or use a motor that will work as a generator(reverse connections to windings)

does anyone see a problem with this?

 

[Brain]

A few...
The t-cases (at least the older ones like we have) are meant to have one input and two outputs - one that is always engaged (the rear), and one that is selectively applied (to the front). The one that goes to the front is driven by a chain, and that is it's weak point as the chain stretches with use/abuse and starts to eat up the sprockets (gears). So simply saying that you are going to use the input as an output and two outputs as inputs makes me think you might get 1,000 miles and then have total system failue. It might work for a while, but I don't think it would be reliable in this configuration.

Another issue is the whole concept of HEV vehicles is to lessen the consumption of gas by putting a smaller motor in place and having an electric motor to add torque to the system when it needs more torque. The batteries are charged with excess motor power and by rgenerative braking (so that when the motor is running it is always operating at it's most efficient point on the RPM/torque curve). I'm just not seeing where this is going to be more efficient.

If you are just looking for some more torque at certain times (while accelerating from a dead stop for example) there are aftermarket systems that use a belt-drive hooked up between an electric motor and your crankshaft (in front) for torque boosts.

Neither one of these will give you extra traction, but will give you extra torque if/when you need it. It could save some on gas because accelerating from a dead stop seems to be waht sucks up the most gas in the Explorers (because they are heavy).

Having 4WD engaged all the time will eat up your tires and t-case...it says in the manual that 4WD shouldn't be engaged for normal driving. The front wheels are supposed to turn slightly faster than the rear tires, and if it isn't slippery, you have a situation where you are dragging the back wheels by the front wheels (which is driven through a chain).

 

[smiley1]

Unless gas prices skyrocket I dont think you will ever recover the money you are looking at investing in the vehicle. It can work but I think you will be disappointed.

Very interesting concept though.

 

[ccanuk]

"So simply saying that you are going to use the input as an output and two outputs as inputs makes me think you might get 1,000 miles and then have total system failue. It might work for a while, but I don't think it would be reliable in this configuration."

ok... so if I attach the output(that I want to use as input) that is chain driven on the reversed TC to the front output on the original, I can get around the issue of wearing that part out. thanks that is a good thing to know.

"I'm just not seeing where this is going to be more efficient."

ok, there is going to be a computer taking wheel speed inputs from the ABS sensors, and an electronic throttle control.

The computer will determine when you are pressing the accelerator, and instead of throttling up the engine, throttle up the electric motor and leave the engine at say 2000 rpm. This will allow the engine to stay within it's peak efficiency range or close to it until the electric motor is at full throttle, then it will increase engine throttle. As long as the front and rear wheels are not spinning more than 5% faster than eachother, in that case if the front tires spin, electric motor throttle will drop and engine throttle will increase until they are within 5% or vice versa.

When breaking, on slight pressure of the brake peddle, regenerative breaking will begin, and the engine throttle will release so the engine can idle. further pushing will engage the hydralic brakes. When maintaining a constant speed, the motor will go into a trickle regen mode recharging the batteries at a slight load on the engine over many minutes instead of full load for a few seconds for acceleration or hill climbing


"Having 4WD engaged all the time will eat up your tires and t-case"
I wouldn't leave the original in 4WD, just the second, and if there is no resistance on the secondary output shaft until the original is put into 4wd would there be a problem? if so I could simply wire the two cases together so that when I push the 4WD button it engages both at the same time.

"Having 4WD engaged all the time will eat up your tires and t-case...it says in the manual that 4WD shouldn't be engaged for normal driving. The front wheels are supposed to turn slightly faster than the rear tires, and if it isn't slippery, you have a situation where you are dragging the back wheels by the front wheels (which is driven through a chain)."

in AWD mode the electric motor would drive the front tires, and the engine would drive the rear tires, as long as both TCs are in 2wd mode they will not be linked, so it shouldn't be a problem.

I think I should be able to see 20mpg awd in city and 30mpg highway, then once I switch to Diesel I should see 30city/45 highway

The benifits I see would be increased handling, at aprox a 10mpg increase in city, somewhat less on the highway, and a 50hp more to work with on the trail.

 

[ccanuk]

"Unless gas prices skyrocket I dont think you will ever recover the money you are looking at investing in the vehicle. It can work but I think you will be disappointed."

well gas is 0.92 CAD a liter here, thats 2.95 a gallon USD

if I double my city mileage I will save $80 per month(spending 160 now) thats 960 per year... so if I spend $5000 I should break even in 5 years assuming gas prices don't continue to climb (HAH!!!)... not including savings from reduction of wear and tear on the engine and transmission as well as the benifit to upgrading from 2wd/4wd to AWD/4WD and another 50hp to draw on. what would it cost to put a 50hp supercharger on my truck which would actually decrease my mpg?

 

[smiley1]

Pioneered projects usually cost twice the anticipated/estimated cost. Also keep in mind that unproven projects or prototypes have unforeseen bugs that reduce reliability and increase cost over completion costs.

I think this is a great project and would love to see your progress. As stated I think this is a very interesting. I just want you to be prepaired to be buried.

 

[mikesparky]

I've been thinking of something similar, but agree that it'd prob be very expensive and have reliability issues. Did you go through with the project?

 

[gijoecam]

It's not a new concept, just a (relatively) rudimentary approach to the way some of the OEMs started the R&D on hybrids 10 years ago.

IMHO, it's seriously not going to be worth the effort. Parts will be one-offs, the control system will need to be designed, engineered, tested, redesigned, and re-tested over and over again, and it'll take an electrical engineer with a pretty solid electronics background hundreds of hours to get it to play nicely with the OEM components.

SAE used to sponsor a collegiate competition to create just such a monster. It generally takes teams of senior college engineering students a year or more to secure the funding, R&D resources, and components, engineer the system, install it, test it, and compete with it. (Ford sponsored the event as recently as '03)

It's not a small task that anyone can do in a few weekends in their garage and see any worthwhile benefits... it's gonna be a nightmare!!

-Joe

edit: Just hit me: It was called the FutureTruck Competition. Search the 'net or the SAE.org web site for more info.

 

[Curtis]

well gas is 0.92 CAD a liter here, thats 2.95 a gallon USD

Im in Orlando and paying the same price.
yesterday was $2.93
I'm thinking they wont go over the $3.00 mark as that seems way more expensive and people just wont do any extra driving if they can help it.
Back home in NF they are paying 1.18 a L....thats more like $4.07 US for a gallon.

 

[BrooklynBay]

There is a Prius forum which Dogfriend is a member of. People are always doing tinkering on those things to increase its efficiency (like the plug in hybrid).

 

[gijoecam]

$3.07-$3.45 here in deetroit. It jumeped up 20-30 cents in the last three days. Not happy...

 

[Silver X]

Cheapest I've saw today was $3.29 for reg. Its outta control! Goes up 15 to 20 cents every couple of days.

I just moved 20 miles farther from work too...

Wife and I are looking for a cheap lease car for me to drive to work.



This is a really old thread. Did the OP ever get started on this project?

We have a few hybrids, electric fuel cells, LPG, and CNG vehicles in our prototype shop. I know they cost us a ton of money and time for R&D. I couldn't imagine trying to do them at home on your own dime. Actually, the LPG/CNG stuff could be retrofit at home relatively cheaply and easily if you have room for the tanks. Then you need access to filling stations with the correct fuels.

 

[BrooklynBay]

Did those LPG, and CNG conversions use multiport fuel injected engines, or did you use those special carburetors which are made specifically for them?

 

[Silver X]

Did those LPG, and CNG conversions use multiport fuel injected engines, or did you use those special carburetors which are made specifically for them?

We used additional fuel rails on a modified stock intake. Some also had the gasoline fuel system to use when the alt fuels aren't available.

I can't say much about them except the configuration is basically a tank in the bed or cargo area (high pressure tank for CNG or a low pressure one for LPG), with fuel lines going to the front to the fuel rails and controllers on the engine. This setup is all computer controlled and can be switched back and forth between gasoline and the alt fuel at any time. You lose some power and fuel mileage with the other fuels, but burn cleaner and lessen the reliance on gasoline. Ours were specifically for state fleet and maintenance vehicles. They were designed to be partially built in the factory then completed at a conversion center.

We also did a few prototype cars and trucks that were only CNG powered and some only LPG. Those had a large tank(s) underneath and another one or two in the cargo area. They still had less range per fill up than the gasoline or diesel versions, so they needed the extra tanks. They were great for local fleet use where you could fill up at the headquarters and not have to look for another filling station on the road somewhere.

 

[BrooklynBay]

They have this kind of stuff everywhere out of the US (UK, Australia, Canada, etc). It's scarce in the US. Have you or anybody else in your company converted a daily driver with this technology (not a prototype or a commercial delivery vehicle)?

 

[Silver X]

No.

There aren't any convenient refilling stations around here yet. I'd consider it if there was one nearby. The way the gasoline prices are going these days, you might see more alt fuels heading to the conventional gas stations sooner than expected. Regular gas is supposed to go up another 10 cents today according to our local news. So it'll be up to $3.39/gal for reg at the cheaper stations.

Time to take out my "Premium/Performance" program and return to the 87 octane one.