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Four Stroke Dryer

Like a retirement home for the noble internal combustion engine...
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It has come to my attention that the days of the internal combustion engine are numbered. The number is more than say,three, but it's not forty one million nine hundred thousand and eleven. The electric motor, being a British invention, is finally coming to be appreciated by the wider world as a superior way of creating movement. It's simple, elegant, and goes about its business with the calm authority of an object that really knows what it's doing. As a contrasting example, I submit the Harley Davidson V-twin motorcycle engine. Essentially this is some low-grade pig iron that produces a little useful rotation before the combination of wasted heat and vibration destroys the structurally-critical chrome plating.

People still buy these things however, not with their brains, but because they're high on a mix of gasoline vapor, expensive marketing and nostalgia. I fear the electric motor will never provide the same experience so the lumpen V twin may continue unchanged for another 97 years until it is outlawed and another way to scratch that itch must be found.

How about a new market? The humble clothes dryer is ripe for some Harley style. Right now, the typical dryer uses an electric motor to spin a drum, a fan to blow air through the drum and because the motor and fan are so efficient, a heating element to heat the air. That's dreadful. Lets replace the electric motor with a 750cc Harley V twin. Now, a normal dryer gets to about 5 kW. The Harley engine idles at around 10kW at the output shaft, that's at least 10x too much power. BUT the horrifically inefficient engine is producing around 15kW heat. Now, just route the air past the air-cooled engine into the drum and you have solved the heating and rotation requirements of the dryer. In fact it's over spec. No problem, we can probably put a generator on the shaft too, get some useful electricity, feed it back into the grid. Best of all, it can probably be made to run on natural gas, like a gas dryer only instead of just burning the gas to make heat, you make it do all the physical work first, and use the same amount of heat anyway.

And who wouldn't want a sweet V-twin idling in their basement for hours at a time?

bs0u0155, Jun 22 2016

Harley 750 twin dyno graph http://www.cyclewor...-on-cw-dynojet-dyno
[bs0u0155, Jun 22 2016]

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       " sweet V-twin idling in their basement for hours at a time "   

       You must be kidding, referring to that irregular plodding as "idling" - but at least the appliances would have a broad dealer support network, lots of aftermarket accessories, and you could identify the users by the colorful clothing.   

       Make mine Moto Guzzi.
normzone, Jun 22 2016
  

       Can I straddle it?
bungston, Jun 22 2016
  

       //Make mine Moto Guzzi//   

       I'm sure various manufacturers will all get in on the action when they realize how many dryers are sold compared to motorbikes. A Triumph triple for me, or possibly one of the desmodromic Ducati engines from the 90s.   

       //Can I straddle it?//   

       You wouldn't be the first, although watch out if a cam chain goes.
bs0u0155, Jun 22 2016
  

       // The Harley engine idles at around 10kW at the output shaft, //   

       Are you sure about that?   

       Harley starters are about 1.5kW - and that's enough to overcome inertia, cylinder compression, and friction in a cold engine. Once the engine is at working temerature, with the oil a little thinner and some clearances increased, 2kW should keep it ticking over.   

       Even with th gears in neutral and the clutch in, that's only going to add 10-15%.   

       If the engine is developing more energy at the output shaft than required by installation losses, its speed will increase from idle. Durrrr...   

       So, by definition, an idling engine isn't producing any output power, otherwise it wouldn't be idling. Loading an idling engine will just stall it.   

       So where does the 10kW come from ? Show your working. Write on both sides of the paper, in ink. You may open your question book now.
8th of 7, Jun 22 2016
  

       Re <link>, still not convinced. Those graphs only start at around 2000 rpm - idle speed is a lot lower than that, 1000 rpm or even less.
8th of 7, Jun 22 2016
  

       I didn't realize Anyos Jedlik was British. Maybe Britain thought they ruled Hungary at the time?
RayfordSteele, Jun 22 2016
  

       //Are you sure about that? //   

       I just took the bottom end of the dyno graph <link> and converted it to kW. Idling isn't exactly as you describe, even with constant fuel and air input there's a little energy to be had. In fact look into full and part load efficiency.
bs0u0155, Jun 22 2016
  

       We have, and it's no-load efficiency which is the issue; it's very poor.   

       It's not possible just to extrapolate those graphs to the point where the process is only just self-sustaining.
8th of 7, Jun 22 2016
  

       Whatever happens, the engine has to move the drum, that's a tiny load, 1/3rd of a horsepower or so. I mentioned a supplementary generator, make that 5kW, then maybe add an automotive style A/C compressor arrangement and use it to condense the dryer exhaust. Call that another 5kW. Then just run the engine at whatever level of throttle is needed. The dryer is arranged to intake the air past all the air cooling fins and possibly some form of exhaust heat exchanger. Efficiency doesn't matter much, you're burning domestic natural gas to make heat in a slightly more convoluted way than a regular gas dryer... only you don't need electricity anymore.
bs0u0155, Jun 22 2016
  

       And you get to change the oil and gap the spark plugs on more things.... I think that's good.
bs0u0155, Jun 22 2016
  

       //a British invention// Sp.: "English".
MaxwellBuchanan, Jun 22 2016
  

       Could there be a Wankel Washing-machine?
Ian Tindale, Jun 22 2016
  

       Would a jet engine not work better?
MaxwellBuchanan, Jun 22 2016
  

       Automotive a/c units have horrid torque loads at low rpms and definitely play with idling behavior.
RayfordSteele, Jun 23 2016
  

       Gee Your Clothes Smell Like Gasoline   

       Follow on to: "Gee your Hair Smells Terrific"   

       YOUR underwear smells like JP4, Max ?
popbottle, Jun 24 2016
  


 

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