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 Potential live diesel project

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cooperised



Location : York, UK

PostSubject: Potential live diesel project   Sun May 19, 2013 5:01 pm

Hello all,

I'm new to this forum, and reasonably new to garden railways, and I've not yet tried building a live diesel - but I've been 'armchair planning' for a while. Smile

I'm located in the UK and modelling UK narrow gauge, so in some ways I'm a bit of an outsider here at cgtrains, but this seems to be where the live diesel action is!

I have a wish list of features for my live diesel project, and it's quite possible that I won't be able to achieve all of them:

  • I'd like to build something compact. Like, Baguley Drewry or smaller (with scale body). No concessions to the IC monster within, if I can get away with it.
  • I want as good a noise as I can get, so I'm thinking of going down the 4-stroke route.
  • If I can get realistic(ish) diesel-electric controls, I'd like to do so, with independent control of throttle and 'notch'.
I'm an electronic engineer by day, so I'm interested in how electronics might be used to make certain aspects of the design and build easier. In particular, I'd like to investigate new ways to interact with a BLDC (brushless) starter/generator.

Firstly, I reckon that by using a DC-DC (buck-boost) converter it would be possible to increase or decrease the voltage generated by the BLDC, with a corresponding decrease or increase in available current. (A DC-DC converter is like a gearbox for electricity, trading voltage for current or vice-versa.) This would have the same effect as changing the kv of the motor, or of changing the gearing between the engine and the motor. I like this idea partly because it would let me choose a BLDC motor solely on the basis of its size and shape, and not on its kv value, and then not to worry about gearing but just to go for direct drive.

Secondly I'd like to develop a circuit that can switch the BLDC between starter and generator modes. I've seen Carl Hibbs's video on YouTube showing a BLDC turning over a Kyosho 2-stroke with apparent ease. Carl, if you're reading, what kind of motor was that? How many LiPo cells were you using?

Thirdly, and partly to make the previous idea simpler, I'd like to convert the BLDC to 'sensored' operation by adding three Hall effect sensors around the rotor and building a new controller. This would give much better stall torque and low-speed running, so it would probably improve starting performance. I could even use it to turn the engine very slowly for a few turns to clear any 'vapour lock' prior to starting. A fully automated start would be super cool. Cool

And last but not least I've been wondering about a spark ignition conversion for the engine, as offered by a number of companies these days - basically it's a Hall effect sensor, a magnet that gets glued into the prop driver (or equivalent), a small box of electronics and a spark plug. Some people then shim the head and run on petrol (with oil of course), but others leave it running on glow fuel (no need for nitro), to keep the temperatures down, and I'd probably follow this route I think. The main advantage should be a much smoother, slower idle because the ignition timing is much more precise and reliable at those slow speeds.

Sorry for the long post! I guess I'd like to know if anyone has tried any of this before? Am I suggesting things that have been tried and found to be useless, or should I shut up and get on with ordering some bits and trying things out? Very Happy

Cheers,
Andy
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KleineDicke



Location : Deep in the Heart of Texas (Houston)

PostSubject: Re: Potential live diesel project   Sun May 19, 2013 6:50 pm

Hello, Andy. Welcome to CGT. Don't worry about being an outsider-- we have a broad spectrum of interests and locations. As you can see, I am in Texas, building my first true garden layout, sort of a Franco-German railway (Alsatian?), mostly remote control battery powered.

Sounds like you've got some big plans laid; it will be interesting to see them come to life. I've not built a live diesel myself, but I do enjoy reading about the projects (something about being an engineer myself, I guess). I look forward to reading about yours.

One other thing - we love photos. The more the merrier.

_________________
Bill Wray

"It is one of the happiest characteristics
of this glorious country that official utterances are invariably
regarded as unanswerable."
-Sir Joseph Porter, First Lord of the Admiralty (HMS Pinafore)
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Carl Hibbs
Admin


Location : Haute Normandie - visitors welcome

PostSubject: Re: Potential live diesel project   Sun May 19, 2013 7:13 pm

Hello Andy and welcome to the forum.

It is not important what trains you model or what you want to model. People here model trains from many countries and even those with no railway at all. Wink
Just share your development with photos where possible.

For the diesel project good luck and ask as many questions as you wish. Most of us probably do not have your electrical engineering knowledge and have done things from a more straightforward modelling aspect.

I have played around with starting quite easily a Kyosho GX12 with a 790KV motor. This was powered by a 6 amp 12volt lead acid battery through a standard blushless ESC and radio control set.
I haven't really pursued this any further up to now as I'm quite happy with pull starting and keeping things basic and simple which is the way I'm continuing for the moment. One day I may build something more complex.

The abounding technology and range availability with brushless motors means that just about every configuration is possible and at attractive prices reducing the need for additional work.
For example I've just ordered 2 motors from HobbyKing rated at 630KV with 5 mm shafts in an 18mm can package at 10 each. It is cheaper to change the motor for a different KV value than buy different gears, and make up a new mounting. scratch
It may even be possible to put 2 lightweight BLDC motors on the same shaft (engine crankshaft even) with different KV values and tap off each one as required. Shocked

The sound issue is so subjective. What sounds like a real diesel?
4 strokes can have a different sound to 2 strokes but it's not always obvious. The small 2 strokes like the GX12 do rev high and sound whiney in their raw state. The bigger machines with better carbs and idle mixture control can be made to sound much deeper.
All sorts can be done to muffle the sound and noise enhancements like a whistling cooling fan which sounds like a turbo charger.

At the end of the day everyone has their own aims, ideas and skillset which makes this an interesting topic.

If you try things just let us know and I will add it to the Live Diesel web page.


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cooperised



Location : York, UK

PostSubject: Re: Potential live diesel project   Mon May 20, 2013 10:21 am

KleineDicke wrote:
Hello, Andy. Welcome to CGT. Don't worry about being an outsider-- we have a broad spectrum of interests and locations.
Carl Hibbs wrote:
Hello Andy and welcome to the forum. It is not important what trains you model or what you want to model. People here model trains from many countries and even those with no railway at all. Wink
Thanks both! I don't feel so out-of-place now. Smile

Carl Hibbs wrote:
I have played around with starting quite easily a Kyosho GX12 with a 790KV motor. This was powered by a 6 amp 12volt lead acid battery through a standard brushless ESC and radio control set.
Thank you Carl. Do you remember the power rating of the motor? (Or just its make and model?) I'm trying to get a handle on how much 'grunt' is required to turn an engine over, and the kv value alone doesn't give me that.

Carl Hibbs wrote:
I haven't really pursued this any further up to now as I'm quite happy with pull starting and keeping things basic and simple which is the way I'm continuing for the moment. One day I may build something more complex.
Fair enough, though I've seen a few of your builds and they're really neat, I wouldn't call them simple. Laughing For me, I guess I'm more comfortable with electronics than mechanics so some of these 'complex' things are closer to my comfort zone than cutting and bending metal. For example, you mention mounting two BLDC motors on the same shaft and switching between them. Good idea - but I'd be more comfortable building a buck-boost converter to change the BLDC's kv value electronically than trying to mount two motors concentrically in a way that didn't just throw itself to pieces. Rolling Eyes

Carl Hibbs wrote:
At the end of the day everyone has their own aims, ideas and skillset which makes this an interesting topic.
Exactly!

Carl Hibbs wrote:
The sound issue is so subjective. What sounds like a real diesel?
...
All sorts can be done to muffle the sound and noise enhancements like a whistling cooling fan which sounds like a turbo charger.
You're quite right of course, it's entirely subjective and a matter of taste. And I don't want to try to recreate the sound of a full-size diesel; I could do that more realistically with an electric model and a decent sound card, but I'm not interested in that. Very Happy I want something that sounds like a model, but doesn't sound like an angry wasp and doesn't deafen me or my neighbours. I've always liked the 'putt putt' idle of a 4-stroke, and I think it might sound about right for a small industrial diesel.

The whistling cooling fan is a great idea. I've not yet decided whether I'll be modelling a turbocharged prototype, but I'll bear it in mind.

KleineDicke wrote:
One other thing - we love photos. The more the merrier.
Carl Hibbs wrote:
Just share your development with photos where possible.
I get the message. Wink Currently I'd only be able to share pictures of a small and fairly bare garden, but as soon as I have something worth photographing I promise I'll post pics of it here.

Cheers,
Andy
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Carl Hibbs
Admin


Location : Haute Normandie - visitors welcome

PostSubject: Re: Potential live diesel project   Mon May 20, 2013 10:38 am

This is the motor I used to start a Kyosho GX12
RC Timer BC3548
It's rated at 717 Watts but was ok on 6 Amps at 12 Volts.

I haven't tried any other motor/engine combinations.

The 'whistling fan' is someting that Jerry Hyde built and does indeed act as (a sort of) turbocharger.
Hyde Mountain Diesel.

You can make a 2 stroke go 'putt-putt'.....well maybe 'putt-putt-putt'..... Laughing
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cooperised



Location : York, UK

PostSubject: Re: Potential live diesel project   Tue May 21, 2013 11:10 am

Great, thanks Carl. I'll start speccing some components. study
One more question (for the moment): do you tend to use flywheels, or do you find the inertia of the BLDC is enough to get a smooth idle?
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Carl Hibbs
Admin


Location : Haute Normandie - visitors welcome

PostSubject: Re: Potential live diesel project   Tue May 21, 2013 11:48 am

I have tried running without flywheels on the Kyosho and other car type engines and found in both cases starting is difficult. Once started they seem to run ok.
However I have read on more than one RC forum about running 'no load' or an unbalanced load on the engine may cause damage.
I know others have tried without flywheels but I don't know of their experiences.
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Saint-Oblas



Location : Lyon, France

PostSubject: Re: Potential live diesel project   Thu Jul 31, 2014 6:01 am

Have you progressed through your project? I am very interested since I am on a similar one. I expect starting my OS 15LA 2 strokes engine with my BLDC but to have it turn around, I must connect a 4 elements LiPo battery to my BDLC which this one:
http://www.rctimer.com/product_575.html
the ESC, which is described as a 10A is becoming quickly hot. I also tried a 30A ESC but took the 10A for its size. I hope the engine will start rapidly.
I am presently on the exhaust design and have some difficulties. I do not expect a sound in any way similar to a real full size diesel, but I do not want to either since I do not think it would be realistic. One does not expect a violin to do the same sound as a double bass and the size ratio is musch less!

Hope to have news of this interesting project
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