Hydraulic Propulsion AND Generator

Discussion in 'Diesel Engines' started by nkurb, Dec 24, 2013.

  1. nkurb
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    nkurb Junior Member

    Hi there,

    Just wondering if anyone has seen a hydraulically run gen set before. I'm in the process of designing a livaboard vessel and would like to provide the ability to run a generator and engine, without the need to have 2 diesel engines. I realize there is a loss of efficiency with such a setup, but I still think the potential benefits overcome that. I'm basically envisioning diversion valves that would decide if you're running the propeller or the generator.

    Any input on such a setup?

    Cheers
     
  2. nkurb
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    nkurb Junior Member

    Also, I realize that a diesel electric setup is probably better for such a setup, I'm just curious if a hydraulic system has ever been used with much success.
     
  3. BMcF
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    BMcF Senior Member

    I know of at least two marine hydraulics companies that delivered hydraulically driven generator packages as a "standard" product over the years. So its certainly been done. One of those companies is not longer in business and I'm not sure if the other still sells the units so I'll not post any links or name. An internet search might turn up something but, frankly, its not a particularly challenging design problem to make up what you specifically will need.



    The efficiency of modern hydraulic drives isn't that bad, really, but you do need to incorporate a heat exchanger in the drive loop.
     
  4. BerettaRacer
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    BerettaRacer New Member

    Years ago one of the major megayacht shore power converter companies was talking about building something like this. It was basically designed for long distance cruisers, to give the ability to bleed energy from the main engines and shut down the gen set to save operating that third engine while underway. But, since main engine speeds vary much more than electronically controlled gensets, a way had to be devised to regulate the output to the correct voltage and frequency. They achieved this by feeding the unregulated power into their own shorepower converter, and thus outputting the correct power to the vessel. In effect, the vessel thought it was on shore power. I believe that market was in the 75-150kw range. I do not know if they ever produced any/many of these.
     
  5. michael pierzga
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    michael pierzga Senior Member

    The big Wally Yacht built in the US early 1990s used hydraulic drive...for a few years till they threw it away. To complex. Noisey and unreliable.

    Normally hydraulic drives are for a special purpose of for short duration thrusting.

    It would be a poor and expensive way to go with a small yacht.



    The other solution would be diesel electric. It would be worth studying

    Some pre package systems are availble from Steyr diesel and are intended for lake operation in no pollution zones

    http://www.steyr-motors.com/marine-...hybrid-propulsion-system-diesel-and-electric/
     
  6. FAST FRED
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    FAST FRED Senior Member

    For most folks the simplicity and efficiency of a shaft to prop from the main engine to push the boat cant be bet.

    The main engine can easily power an hyd system that includes a hyd generator head for power while under way.

    A stand alone gen set can be used to power the same AC generator head , the windlass , the bow or stern thrusters ,water maker, refrigeration, deck crane , and perhaps a chain sprocket to the main shaft as a get home setup. Proper gen engine sizing would not allow ALL these items to be operated at the same time.

    This is a very versatile package for the genuine cruiser.

    And everything is OTS.
     
  7. gonzo
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    gonzo Senior Member

    The extra weight of the setup, the extra weight of the fuel (it will be very inefficient), hydraulics use high pressures which are inherently dangerous. It would be more efficient and cheaper to run everything on low voltage and use the main engine to charge batteries. For long distance cruising, either you change your way of life to be thrifty, or you have a load of cash to pay for energy.
     
  8. TeddyDiver
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    TeddyDiver Gollywobbler

    I studied few years back the same setup. Found it possible but didn't find perfect match for the hydraulic pumps and motors for my specs. Anything else would be waste of money...
    Now going for a setup with one main engine with two PTO's, one on the block for hydraulic pump for windlass and bow thruster, and other one on the gearbox (not many choices) having a big alternator inverter combo (6 to 8 kVA). And of course a CPP propulsion...
    BR Teddy
     
  9. FAST FRED
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    FAST FRED Senior Member

    Now going for a setup with one main engine with two PTO's, one on the block for hydraulic pump for windlass and bow thruster,

    The bow thruster is better powered by the gen set.

    Most maneuvering is with the main engine at near idle , so little power is available for a thruster.Ditto for windlass.

    The gen set can be at full rpm RPM while docking or lifting the ground tackle so plenty of power can be had.

    The big advantage of Hyd over battery power for may high power users (like a thruster) is there is no limit of ON time. Frequently a huge hassle with DC stuff.

    Always look in the users manual before any DC purchase to find operating limits.

    When a Hyd is overloaded , like a windlass, it simply stops working , till you increase the pressure or reduce the load.

    DC at best will pop a circuit breaker , at worst the White smoke escapes,,,,forever!
     
  10. BerettaRacer
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    BerettaRacer New Member

    Sorry, but I don't know where your getting the idea running a hyd gen from the M.E. would be inefficient. It now costs me about $1000/day in fuel and maint. to run a 100kw gen in EU waters. My M.E.'s are 2000hp each, if I can bleed 50hp from each M.E. they won't even notice the load. Also gives gen-set redundency so that I can legally leave port, or have peace of mind while one of the primary gensets is being serviced. And we absolouty do not get 100kw power from low voltage DC.
     
  11. BMcF
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    BMcF Senior Member

    The typical large bow thrusters (30-40kw.or more) in yachts are hydraulic. In many cases, the power for those is provided by large-displacement PTO-driven pumps; the displacement of the pump(s) is selected to be large enough that the full thruster power is available at ME idle.

    Underway, the same pump(s) will be taking care of the power required for stabilizer operation but with a huge power margin since the sizing of the pumps was dominated by the thruster requirement. So, a parasitic hydraulic gen set makes perfect sense...and is the reason there are many of them in service in that type of setting.
     
  12. nkurb
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    nkurb Junior Member

    For the system I was envisioning, the drive system would be similar to what is run in some of the narrowboats in Europe:

    http://www.betamarine.co.uk/inland/Beta_Hydraulic/hydraulic_propulsion.html

    The vessel is mainly meant as a live aboard. Travel would be infrequent, but obviously still required at times. Propulsion efficiency isn't a huge requirement. Although, I wonder how much loss there really is considering hydraulic systems provide the ability to run a 0 degree angle prop rather then the normal 8 degree +. I hear a lot about the problems with hydraulic leaks and such... but I feel like if you're running short runs with high quality equipment, it shouldnt be much of an issue. I've seen normal JIC based hydraulic systems on boat lifts and such run for ages with no sign of leaks.

    Maximizing living room in the boat means trying to limit the number of diesels to 1. Since propulsion is not a huge priority, some of the hybrid electric systems seem like overkill.

    I want to avoid the need for a second engine, but still provide the diesel with a proper 'load' when using it to generate power. I guess you would have to be sure to run the engine at a set RPM when using it as a generator...which might be difficult.
     
  13. TeddyDiver
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    TeddyDiver Gollywobbler

    I didn't take a closer look but reckon it's open circuit hydraulics so pretty simple but a unefficient setup, maybe 35% less compared to conventional gear-shaft-propeller setup (I won't buy their numbers). Should work quite ok in occasional use..
     
  14. Adler
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    Adler Senior Member

    Info

    A power plant concept near to your description had installed in several
    vessels since 2002 and are still running properly on heavy duty.
    See the attached files.
    The power pack mode designed to run the engine at 1500rpm controled by a
    Woodward speed controller size/type1724. The Hydraulic pumps are Sauer-Danfoss piston_closed cirquit or Denison vane_open cirquit with Danfoss
    Proportional Valves PVG-120.
     

    Attached Files:


  15. FAST FRED
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    I guess you would have to be sure to run the engine at a set RPM when using it as a generator...which might be difficult.

    Not with a hyd driven generator head , the controller will run it at the desired speed , as long as there is sufficient pressure/volume for the AC power required.

    With a liveaboard not much moving boat why have much of an electrical system?

    The big power hogs are heat and refrigeration , then cooking , all can be done silently with propane.
     
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