Thursday , February 22 2018
Home > Engines > New Project Plans: A Pressure Controlled 2-Stroke Engine by Jan Ridders

New Project Plans: A Pressure Controlled 2-Stroke Engine by Jan Ridders

This is the third and final engine contributed by Jan Ridders of the Netherlands, a pressure controlled 2-stroke engine.


I asked Jan to pick his most simple designs in each of 3 categories, Stirling, Flame Eater, and IC.  This set of plans is for his most simple IC design, a pressure controlled 2-stroke engine. If you’d like to see the other two designs shared by Jan, they can be found here: Jan’s Coffee Cup Stirling Engine and Jan’s Flame Sucker. And of course, all of Jan’s other engines can be found by visiting his site, which is written in both English and Dutch.

Here’s an animation and a description of the principle behind Jan’s masterpiece (excerpt from Jan’s site):


A ball valve only opens when the pressure below the ball is higher then above the ball. For the upper valve this is only the case, and for a very short time, when the piston reaches the exhaust port. The pressed gas mix below the piston and between the two ball valves is injected then, filling the cylinder and pushing out the remaining burned gases. Before and shortly after that moment the pressure above the ball in the upper valve is always higher then below the ball. When the piston is moving upwards there is an overpressure above the ball (gas mix compression) and a lower atmospheric pressure  of the sucked-in fresh gas mix below the ball. When the piston is moving downwards there is a high overpressure above the ball due to the combustion (power stroke) and a much lower overpressure of the compressed fresh gas mix below the ball. So also during that power stroke the upper ball valve keeps closed until the piston opens the exhaust port.

So the timing of the process is exactly right and automatically controlled by the alternating pressures in the system. That is why I called this engine the “Pressure controlled Two-stroke”.

Here’s a video of the engine in action:

For more information on this engine (including construction tips and trouble shooting) please visit Jan’s website. Jan also has many other engines on his site and he shares his plans freely with anyone by request.

I’d like to say Thank You one more time to Jan Ridders for sharing multiple sets of plans with this site. By sharing your plans you’ve helped this site grow.

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About Tyler

Tyler is a hobby machinist and 3D printing aficionado. He teaches computer programming and web development at Highline College near Seattle. Tyler founded Projects In Metal in 2008 because he was frustrated by the lack of free plans available for hobby machinists.

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  1. This engine  is great, a lot of time has been put in to that gem if i quit work for good i think i would try to build one of these one day.

  2. I'm working up to this engine. At this point it's a bit past my skill level. I could proably make it, but it might not run when I'm finished. So I know what you mean. However, I anticipate that this little engine will be a part of the family within the next two or three years. I just need to refine a few skills before I try to tackle it myself.

  3. I am also going to try and build this after I have finished the “simple air engine”.


    It looks like a lot of work!!!!


    Mtw fdu.



  4. I have built the coffee cup engine and it turned out real good, now I’d like to build this one. Would anyone have a detailed plan of the ignition circuit used in this engine? I am having trouble understanding what parts are used to make the spark.



  5. Indeed a beautiful engine.  I look forward to getting my mill running so I can do something like this.