A Hybrid Stirling Trike

Discussion in 'Motorized Tandems, Trikes and Recumbent Bicycles' started by Intrepid Wheelwoman, Feb 21, 2015.

  1. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    With work on my cyclecar held up while I search out more parts I thought I'd go ahead and get the Stirling trike into at least a rolling and pedal-able condition in the meantime. I first proposed the whole idea here ......http://motorbicycling.com/showthread.php?t=34913&page=161 ......Only I thought it would be more useful to give this project a thread of its own.

    The basic trike was purchased some time ago while I was still living in the Big Smoke and it's been hanging around my workshop ever since. I did start on turning it into a solo lowrider/cafe racer sort of thing by taking off the trike axle and installing a Villiers engine, but while everyone who saw it thought it was cute it was near impossible for me at my age to tuck all 5ft 10inches of my skinny self around the thing without risking doing myself a mischief. So it languished and got called names everytime I nearly fell over it.

    Putting the trike axle back onto it was definitely the way to go, but it was my daughter's influence as a keen electric vehicle tinkerer that made me decide to put the Villiers engine back on the shelf. Though with me being me I felt I needed some species of engine with a nice flywheel fitted to the trike or else I'd be left feeling all glum about the project.
    Essentially the trike is going to be propelled by a 24 volt DC electric motor and the Stirling engine will be used to charge the batteries.

    Being a velocar type I've decided that the trike will be getting a lightweight bodyshell too. As I am very much into recycling I'm going to be using a redundant clothes hanger wardrobe frame thingy as the main source of material for the body frame. As a rule I've found that tricycles, - especially the traditional type of tricycle, - are treated far more like a vehicle by other road users than they do a bicycle. With a bodyshell of vintage design on the trike I think I should have very few problems at all :)

    [​IMG]

    I've ordered some brazing rod and a pair of new welding glasses which will be here next week so once they arrive the fun will begin :D

    [​IMG]
     
  2. bluegoatwoods

    bluegoatwoods New Member

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    You'll have to help me. "Stirling engine" seems familiar. I think I've heard of it. But I'm not coming up with anything.

    What is it?
     
  3. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    A Stirling engine is an external combustion engine that works by heating and cooling air or other gases as they cycle through the engine. Their big advantage is that they will run off any source of heat.
    I'm going to be using what is called a 'gamma' Stirling engine which uses two separate cylinders, one for the displacer and the other is the power cylinder,

    [​IMG]

    https://www.youtube.com/watch?v=0t8LEKf04TA
     
    #3 Intrepid Wheelwoman, Feb 22, 2015
    Last edited: Feb 22, 2015
  4. wheelbender6

    wheelbender6 Active Member

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    Doesn't the Chevy Volt have a Stirling engine to charge the batteries?
     
  5. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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  6. silverbear

    silverbear The Boy Who Never Grew Up

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    Anne,
    I'm glad to see you're going ahead with this project as it is interesting. What do you envision as the heat source? In my part of the world wood is plentiful and free. What type of batteries do you plan to use? Lead acid? I'm guessing you may have some from a former build, as well as a controller and charger for them.

    I really shouldn't even be thinking about it, but I do have a 36V. front wheel pancake engine and still have the lead acid batteries and such. What will you use for generating the electrical charge, an automotive alternator or generator producing 12 volts? Will the sterling engine driving the charger be able to keep up with demand from the electric motor? Will this be pedal assist?

    Whatever you do it will be of great interest, so I'm signing on to your thread... carry on as soon as I get my popcorn and find a seat.
    SB
     
  7. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    To answer your questions Silverbear :) - Yes I'm going to set this trike up for pedal assist. Pedals are just too darn useful on low powered vehicles to go leaving them off. I'm going to install another bottom bracket and pedal shaft further forward as well as lowering the seat which should give me a semi-recumbent arrangement and the ability to give the pedals a bit more of a push.

    After a lot of discussion my daughter and I decided that the new calcium alloy SLAs would be the best choice for our pattern of use rather than get into the expense and esoteric strangeness of magic batteries full of noise and fire just waiting to burst out. I do have a pair of near new 20 amp hour SLAs already and a major benefit of selling our car is that we have the money in hand to buy more.
    While I do have a spare 24volt controller for brushed motors which may get used on my Hercules trike, my daughter is developing a programmable controller for light electric vehicle use which hopefully will become the standard fitting on our small fleet of electric bikes and trikes.
    [​IMG]
    It's awfully nice having a daughter who studied Computer Science and Electronics at university :D

    We're going to try using a modified car alternator for charging batteries first of all, but we also have a lovely French made DC motor in reserve which can be converted to a generator if we need to. I don't think I will be able to build something that will keep up with the motor output. The Stirling engine's job will be more about charging the batteries when the trike is stationary, but I guess that will be experiments and tinkering territory once everything is put together.

    As to fuel, I will be using the larger of the two vintage kerosene stoves that I have to provide the heat. The guys on the Stirling engine forum seem to think this will work Ok, but I will make a wood fired stove at some stage that can be retrofitted if I need to.

    As to various bits and bobs I still have some of the parts I used to build my previous trikes as well as a large pile of hoarded electronics and computer hardware which can be used as a source of parts during the prototyping stage.
    Selling the car has been the biggest boost to our plans though as it gave us an injection of cash which as enabled us to buy such things as a professional electronics soldering station, accurate measuring equipment and other expensive tools we couldn't ordinarily afford. It might seem odd to sell our car, but neither my daughter or I are medically able to drive safely anymore and the thing was just sitting on the driveway getting in the way and doing nothing. Being what is these days considered to be a classic Japanese car the best thing we could do was turn it into money.

    If you've got those electric bike parts to hand Silverbear it wouldn't be so difficult to put together a spare bike for getting about on. Or you could replace the front wheel on your sidecar outfit for a little extra boost should it be needed :)
     
    #7 Intrepid Wheelwoman, Feb 23, 2015
    Last edited: Feb 23, 2015
  8. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    My brazing rod and welding goggles arrived this morning. The brazing rod is the new fangled flux coated type and it's made by the same people who do the gas canisters I'm using so I would imagine my new torch should be able to melt the stuff.

    But shock horror, when I unpacked my new goggles one of the lenses was broken :eek:
    [​IMG]
    A quick email to the supplier and the situation was sorted. He's sending me a replacement pair tomorrow and he wasn't bothered about me sending the damaged ones back and said I could keep them. Now that's wot I call customer service!

    To celebrate I purchased a new hat for myself at the St. John's Ambulance Charity shop on the main street in our little town. It's a nice tweed cap with an 'Aerial' brand label and is just the sort of thing a Steampunk mechanic girl should be wearing.
    [​IMG]

    Another nice treasure I've found for this project is this wooden toolbox. It's beautifully made and has a lovely patina so it will be just the thing to help this project along. And no doubt wot I put in the toolbox will help the project along once we get to the road testing stage.
    [​IMG]
     
    #8 Intrepid Wheelwoman, Feb 23, 2015
    Last edited: Feb 23, 2015
  9. cannonball2

    cannonball2 Active Member

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    Is the Stirling/generator unit going to be a stationary charge station or is it going a long for the ride? A very interesting build either way! Don't have one of those hot springs that NZ is famous for near by do you? Could use them as a heat source for the Stirling?

    I saw one of those fans in an antique shop in Savannah(Ga.) and wondered if it blew anything but hot air, still it was a way "cool" contraption!
     
  10. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    The Stirling/generator will be coming along for the ride CB as the aim is to build a vehicle that's capable of extending its range by being able to charge its own batteries.

    We don't have any hot springs around here by the way. You have to go around 100 km further south to find those :)

    The gamma type of Stirling engine that was used in those antique fans is both mechanically simple and has the potential to be reasonably efficient too. This will be the same type of engine that I will be using.

    Have a look at this one if you want to see what sort of power they can output...... https://www.youtube.com/watch?v=9M-8qtIVHFg&index=20&list=LLUzQA-WUr47ci641J7iRD8w
     
  11. cannonball2

    cannonball2 Active Member

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    That's pretty impressive! The car alternator idea sounds a bit power hungry. Most Ebike chargers charge in 3/5amp range which sounds doable. Could an R/C brushless motor be converted? I know some of the gasoline powered helis at my club had on board charging systems using one of the type motors and a regulator. Seems the reduction of the mass turned even if the charge loading is the same would be easier on the Stirling. Unless you are looking for some flywheel effect once it gets rolling.

    Have you considered fuel pellets for pelletized stoves? I think for this usage they would be fairly economical.
    They would be very compact/freeform to carry and could be burned in a fairly small burner. Don't know how they "wood" compare to the cost kerosene but they are odorless and clean to handle. Ideally finding cast off materials for fuel is the best idea as they cost nothing and are just about everywhere. I had a newspaper roller that made logs from it, done right the logs burned a good while.

    Very interesting idea this build of yours!
     
    #11 cannonball2, Feb 24, 2015
    Last edited: Feb 24, 2015
  12. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    I'm looking at tracking down a source of wood pellets at the moment as I'm going to build a wood gasifier as well based on a no weld design on You Tube.

    https://www.youtube.com/watch?v=20RhuGSYN5Y&list=LLUzQA-WUr47ci641J7iRD8w&index=4

    I wanted to try the kerosene heaters because they are so wonderfully retro and also because that was what those vintage Stirling fan engines used as a fuel. The heater I'll be using has a seriously larger circular wick and it's capable of putting out a lot more heat. Wood fuel is going to be an option for the future though and when I make up the firebox I make it so it can be readily changed over for the kerosene heater with the minimum of fuss.

    Mockup to show heater placement..
    [​IMG]
     

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  13. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    Your point about the generator is a good one CB and I can foresee much experimentation before the ideal setup is found. One of the Stirling Forum guys used a car heater motor on his engine and I have other small motors I can try as well.
    The engine will have a fairly impressive flywheel, but of course not a particularly large power output so matching the load to the engine is important if I want to avoid frustration.
     
  14. Ludwig II

    Ludwig II Well-Known Member

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    Query: improve heat exchange efficiency of the engine by using ice as a heat sink?
     
  15. bluegoatwoods

    bluegoatwoods New Member

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    Just a guess here.

    Measurable results will likely require so much ice that it'll be impractical.
     
  16. Ludwig II

    Ludwig II Well-Known Member

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    It was just a thought, based on the engine requiring a temperture difference to operate.
     
  17. bluegoatwoods

    bluegoatwoods New Member

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    Sorry there, Ludwig. It's not like I really meant to shoot down your idea. And don't forget; I might be wrong.

    You know.....it wouldn't be all that hard to calculate how much ice could do how much cooling.

    Now all we'd need is the Calorie (or BTU) output of the engine in question.
     
  18. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    The usual trick is to water cool the cold end of the displacer cylinder. For maximum efficiency the ideal situation is to remove as much heat from the cold end as is being put into the hot end.
     
  19. bluegoatwoods

    bluegoatwoods New Member

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    If you cooled the displacer cylinder with water and then ran that water through a coil (radiator), it would seem as though that would displace calories into the atmosphere more efficiently than if this cylinder were merely being air-cooled.

    On the other hand.....this would mean that you now must install a coil and pump water.

    We'll have to keep on thinking and making suggestions. In the end you might just have a real Rube Goldberg machine. :)
     
  20. Intrepid Wheelwoman

    Intrepid Wheelwoman New Member

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    The guys who are really into Stirling engines end up with all manner of extras on the engines they build as they seek for greater efficiency. The really serious ones will even experiment with sealed systems running gases like Argon under pressure. I prefer a more middle of the road approach which means that a pump and a small radiator is fine, but anything else outside of sensible plain Victorian engineering will be banished from my gaze.

    [​IMG]
     

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