Since there's no classifieds section, I didn't know where to post. I'll keep the post short, but feel free to ask anything.

I'm looking to build a hydraulic hybrid (probably gasoline) vehicle. We've built a few electric go-karts, and are presently working on a full-size car. This is something I've always wanted to do, and have been collecting parts for the last few months. I've been able to surplus almost everything else, but couldn't find a suitable motor. Had a few close calls on eBay, but no dice. Before I send of $2k+ to Rexroth and wait nine months, I'm giving this a shot.

I need a 80-150Hp, maybe 71cc, variable piston motor, like a Rexroth A6. If it'll go down to 0 displacement, that would be awesome. The accumulator is rated for 5000psi, I'd like to run the system up there if possible. It doesn't have to be pretty, so long as it'll spin for a hundred hours or so.

Thank you!

Sergey

If you need other miscellaneous parts, like crossover relief valves, or pressure reducing valves, we have a bunch of clearance items that are about 65% of the original cost (like our Hy-Spec pressure reducing valves on for $89.93). We don't have any variable displacement piston pumps hanging around, however.

I'm waiting on the pump to get some of the other components, but I'll definitely check it out. The motor will determine the operating pressure, and the overall system size.

Two of our local Salvage yard had a lot of hydraulic equipment the last time I was there checking a winch system. However, that was 15 years back. A lot of it was new equipment from some large local companies spare parts for machines that had been replaced or removed. They wanted it off hteir inventory list and only got scrap metal price for it.

You could possibly check your local scrap yard to see if they might have hydraulic stuff also.

That's a neat idea. There isn't much heavy industry around here, but I travel quite a bit.

Are you still in search of a motor? If so, I may be able to help...

Yes, very much so. What do you have?

It depends, what kind of mount, shaft and porting do you require?

I could probably get my hands on a max displacement of 3.34 in3/rev minimum .96 that will run at your 5100 PSI.

Everything will be custom built, so the physical dimensions aren't critical. The motor will be run in an open circuit. Direct displacement control is preferable, but I can make other methods fit. Displacement that can go all the way down to 0 would be awesome.

Do you have the model number for the unit?

What kind of pump are you using?

I have a Rexroth A10vso28 for the pump, and I *just found* a Rexroth A10VE55.

Now the fun begins. As soon as I'm convinced that the system works, I'll spring for a composite accumulator.

On that subject, I've been researching the safety/legality of having a charged accumulator in a vehicle. I realize that all cylinders must have caps, but how does that apply to accumulators? The gas end of the accumulator is sealed.

Accumulators gas end is basically a schrader valve close to a valve stem on a tire except once charged you tighten the nut on it which closes the valve off. As far as legality on highway use I am not an expert but here is a statment on Compressed Nitrogen transportation. Read the exemption part This is for Canada but I believe US laws are very close

http://www.transportation.alberta.ca/Content/docType272...duction/nitrogen.pdf

How do you plan on running the hydraulic pump? You trying for complete hydraulic drive? If so what kind of top speed are you looking for?

This is preliminary. I'm going to build a test rig to test a few ideas before we build the car...

The pump is connected directly to the front wheels. Its displacement is controlled by a pedal mounted directly in front of the brake pedal. This way hydraulic assist is applied first, and conventional brakes are seamlessly integrated. When the accumulator fills up (or something breaks), the car still stops when you step on the brakes.

The drive motor is attached to any pair of wheels, and its displacement is controlled by the throttle. If I can find a drive clutch, I'll use it to avoid spinning the motor the whole time (shock issues not withstanding).

The system will coast by reducing the displacement of both the pump and motor to zero. A small, fixed-displacement pump will recharge the accumulator by being placed in parallel with the main pump. Both pumps will be isolated with check valves, and both will work simultaneously if need be. The small pump will run from either an electric or gas/diesel motor, which can be activated by monitoring accumulator pressure and vehicle speed.

The drive motor is absolutely enormous; top speed will be limited by accumulator volume and auxiliary pump power.

There's a lot I didn't cover, but please feel free to comment or ask questions. I can't find any rules for transporting accumulators with an active hydraulic charge, no surprise there. I hope you don't read about me in a newspaper after an accident.