Diesel engine

[Roger HartParticipant @rogerhart88496]

Is is practical to build a true diesel engine?

[Roger HartParticipant @rogerhart88496]

I have read ME off and on for many years but a cannot remember seeing a design for a diesel engine of the hot-bulb/injector or injector type.  Fuel to be conventional automobile diesel or possibly paraffin.

 

Is this a practical proposition?  Has it been done in model size?

 

Roger H

[JasonBModerator @jasonb]

Can’t help with any articles but I saw This Link to some hot bulb engines on another forum yesterday, worth a look, there are some videos of them running and construction details

 

Jason

[LADmachiningParticipant @ladmachining]

Strictly I.C magazine published a design for the 'Dux' 10cc miniature single cylinder diesel engine with working fuel injection.  It was designed by Martin Alewijn.

 

Back issues of the magazine are available still, according to the publisher's website.

http://www.strictlyic.com 

 

I have not heard of many being constructed, but I certainly intend to try and build an example one day!

 

Anthony

 

Edited By Katy Purvis on 01/06/2015 09:47:12

[Martin CottrellParticipant @martincottrell21329]

Hi Jason,

 

Thanks for the link to the hot bulb engines. This site is well worth a look as the chaps engines are absolutely exquisite and if you check out the videos you’ll see they run as good as they look!

 

Regards Martin.

[Roger HartParticipant @rogerhart88496]

Hi Jason and Anthony

 

Thanks for the links.  I checked out the hot bulb engines – beautiful – just what I had in mind.  The horizontal engine looks a lot like a Wyvern.

 

I may get the Dux info for a look at a more modern design.  Meanwhile I have to complete Dave Parkes’ 2 stroke job.

 

Thanks again.

Roger H

[David Clark 13Participant @davidclark13]

Hi Roger

How about letting us see some pictures of the two stroke job?

Dave is working on an Anzani at the moment.

Hopefully it will start in 4379.

Dave has had computer problems, hopefully sorted.

regards David

 

[Sub MandrelParticipant @submandrel]

A few years ago there was an article on a Lanz Bulldog tractor. If I recall correctly it didn’t use hot bulb ignition, although it had a working blowlamp!

 

The problem with hot bulb is scale effects I imagine. I can see no reason why injectors should not work, as long as you can meter small enough amounts of fuel accurately.

 

Neil

[Richard ParsonsParticipant @richardparsons61721]

In Mr Diesel’s original engine the fuel was mixed with the air before it entered the cylinder.  These are found amongst the Compression Ignition types used in model aeroplanes.

The engines you are looking at are the ‘solid injection’ type where fuel is injected into the cylinder at or about full compression.  The real problems are the injector, and the injector pump which contains fuel dosing control to get the fuel correct for the load.

Unless you are using a ‘common rail’ engine with electronic control, which is very different and uses a single pump.  The injector has to stay shut until the fuel reaches a certain pressure when it opens squirts in its load and snaps shut.  It has a ‘dribble pipe’ which then opens to overcome the ‘water hammer effect’ and return the surplus oil to the feed side of the pump.

The injector pump which is controlled by the governor has a rotating cylinder liner. This has a triangular hole in one side.  As the governor decides that more oil is needed it rotates the cylinder exposing a larger opening to the output slot and allowing more oil to be injected.  You needed one pump per cylinder.  These could be either on the cylinder head driven by individual cams or as a block of pumps driven by the camshaft and supplying the injectors by pipes.

By the way do not get confused by the direct/indirect injection systems devised by Ricardo and give better performance by better mixing.

[Sub MandrelParticipant @submandrel]

I was reading some MEs from the mid-1990s. There was an article about a 1/12 size working diesel, but it was a big marine engine! I also saw a single picture of amuch smallwer engine made by apprentices from a big German engineering firm.

 

I’ll try and spot the issue numbers.

 

Neil

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