Hydraulic Pump & Motor
Hydraulic Pump & Motor
(OP)
I am looking into using a hydraulic drive system in an electric motorcycle. My reason for doing this is that most braking force on a bike is in the front wheel, so that's the place to recover energy in a regenerative system. However, because of the way the front wheel must move, it's difficult to have a mechanical linkage to a generator (leaving aside the possibility of an electric hub motor, which I believe is heavier than a hydraulic motor of similar spec).
So, I'll need a hydraulic device that can be both driven as a motor (for going) and that can produce pressure as a pump (for stopping). (A similar device, run backwards, will be connected to the electric motor/generator.) My question is, what types of hydraulic pumps/motors have good characteristics when run "backwards?" I've found some motors on surpluscenter.com that say "can be run as pumps;" is there a particular type of motor or pump that works better one way, or about the same either way?
Thanks!
So, I'll need a hydraulic device that can be both driven as a motor (for going) and that can produce pressure as a pump (for stopping). (A similar device, run backwards, will be connected to the electric motor/generator.) My question is, what types of hydraulic pumps/motors have good characteristics when run "backwards?" I've found some motors on surpluscenter.com that say "can be run as pumps;" is there a particular type of motor or pump that works better one way, or about the same either way?
Thanks!





RE: Hydraulic Pump & Motor
Gear pumps generally have no issue running forwards, backwards, or with either side pressurized or not.
RE: Hydraulic Pump & Motor
I may end up putting together a test system, just to see how (in)efficient it is. If it's much worse than chain, then it probably won't recover enough via regeneration to make up for the expense, weight, etc.
RE: Hydraulic Pump & Motor
ISZ
RE: Hydraulic Pump & Motor
That doesn't sound so good...even assuming 90%, I'd be at 81% overall for going electric->hydraulic pump->hydraulic motor. The motor itself is probably no better than 95% or so. I suppose I'll have to go with chain and only the regen I get off the rear wheel.
RE: Hydraulic Pump & Motor
RE: Hydraulic Pump & Motor
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Hydraulic Pump & Motor
That's lower than I'd expected, but still, I don't want to choose a primary drive system that's down on efficiency, just so that I can have better regen. Maybe I can come up with a front-wheel system that <i>only</i> operates during braking (to drive the electric motor in generating mode). If it's got very low drag when not engaged, it might work.
Thanks for the help, everyone!
RE: Hydraulic Pump & Motor
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.