Model stationary diesel engine plans - a rare item indeed. It is not that difficult to build a self ignighting engine and model aero engines are a good example. Fine Hanson (Denmark) has built many fine examples however, he is not interested in sharing his designs or information. His engines are low pressure spray injection using I believe kero mixed with ether typically 30%. You may also note that the jerk pump used for the fuel is adjusted via a wedge which changes the stroke length. The problem is, it also changes the injection timing. His injector is of the popit type which has its limitations altho it works on engines with small diameter cylinders. Basically, if you can obtain reasonable cylinder pressure say 100psi and can inject (spray) a very small amount of voitile fuel then you can get the engine to run. Note, ether has the lowest self ignition point of all of the available (to the average person) types of fuel - just need to mix it with some kero.
I went down the path of designing a true diesel that is, one that will run on diesel. I started down the path of building a proof of type model that is, something that would go into the bin when I had finished with it.
Over a two year period, I made 12 fuel pumps and 8 injectors as well as rebuilding the engine twice. The poor thing now has so many holes where I changed things around it dosn't look the same as it once did.
Through this Forum, I was given good advice from several people and on that advice , I went back to basics. To run as a true diesel, you need approx. 500 psi to ignite the fuel. That means 20:1 minimum and no leaks. I set up a test and measured 300psi - not good enough so back to the drawing board. I made a blanking plate with commercial non return valves and a pressure gauge then ran the test again and was approaching 350psi. Made a new piston with additional rings and I now had well over 500psi and note, you could hardly turn the flywheel over. I reworked the valves and a further test provided an average of 500psi.
Then came the fuel pump problems. The best I could obtain from a conventional jerk pump was 1200 psi and you need a minimum of 1800 psi. In the end, I purchased a cheap small Chinese diesel engine fuel pump and removed the piston and its cylinder. This combination could produce over 4000psi so I now had a working pump.
My original injector was based on a pintal type which worked modestly well but was more of a spray rather than a mist and also dripped. I ended up purchasing the smallest pintel injector nozzle I could fine and made a new injector housing for it. The arrangement produced a very fine mist such that it was very difficult to see.
Except for some work on the timing, the engine ran reasonably well. This is a little long winded to get to the availably of suitable plans but note, you need to decide if you want a true diesel with all its problems or something simpler. What most people do not appreciate is, if you want to build a true diesel the pressures between the real thing and your model will need to be much the same. Basically you can't change the physics involved.
One engine I would recommend is the model of the Lister Diesel which was serialised in Model Engineer some time ago. A friend of mine purchased a complete engine and restored it as some of the components could have been better made. It now runs quite well on a 30% ether mix. I have included a photo of his engine which is running. I also have some info on it.
Other than that, you could take almost any four stroke engine design and modify it to run as a self igniting (diesel) engine. I am currently building a Fairbanks Morse three cylinder engine (photo included) which uses igniters. Also a work in progress, is a single cylinder vertical airblast diesel based on a 1904 engine located in Denmark.
I have acquired a wealth of information on these engines and if there is something in particular you are needing just send me a personal email.
Bruce W-S
Western Australia
Below is the part finished Fairbanks Morse engine
My proof of concept true diesel engine
