OTTO-LANGEN

ATMOSPHERIC ENGINE

Part one by Julius de Waal

In 1864 Otto and Eugen Langen set up the first internal combustion engine making company N A Otto & Cie and succeeded in creating a successful atmospheric engine that same year. The factory ran out of space and was moved to the town of Deutz, Germany in 1869 where the company was renamed to Gasmotoren-Fabrik Deutz. Gottlieb Daimler was technical director and Wilhelm Maybach was the head of engine design.

First version of the atmospheric engine had a fluted column design by Eugen Langen. The engine has its power stroke delivered upward using a rack and pinion to convert the piston's linear motion to rotary motion.

The engine ran at 12% efficiency and produced .5 hp at 80 RPM. It won the Gold Medal, at the 1867 World's Fair in Paris, paving the way for production and sales that funded additional research.

Notwithstanding its commercial success, the company produced 634 engines a year by 1875, the Otto and Langen engine was at a technical dead end. It produced only 3 hp, yet required 10–13 ft  headroom.

In 1882, after producing 2,649 engines, atmospheric engine production was discontinued. This was also the year that Gottlieb Daimler and Wilhelm Maybach left the company.

The engine makes a fascinating and most attractive model. A design by Emmett Lenaz in the US, and later research by Wayne Greening. set the ball rolling. MEWS showed drawings found on the internet to Julius, who took a break from his steam engine design work to produce metric drawings of the Otto-Langen. Anyone who is interested in building in imperial measurements can find drawings on the internet (which may need some revision), together with some building notes which we shall also include on MEWS (see below).

Click on drawings to download - for personal use only.

Part two here.

General machining information for key components:

  1. 1.The column – You will find it easier to drill and bore the column before turning the outside. If you plan on running the engine, you will need to have the bore honed/lapped. Use final bore diameter when turning the piston. The outside is finished by any method you prefer...However, do not drill and tap the 4 valve port stud holes until the port face  is soldered in place. The exhaust and port face are also spotted through port face. The 10-32 holes which are drilled and tapped in the top of the column must be centered on line with the bore.

  2. 2.The Rack - Can be made from scratch or from purchased standard rack stock. Be sure the centerline of the piston and the center of the rack are in line.

  3. 3.The Top Plate – The dimensions for the drilled/taped holes on the top plate are important in order to ensure proper alignment of the Rack Guide Assembly with the cylinder bore. The location of the bearing block holes is

  4. 4.critical to ensure proper meshing of gears and smooth running of the flywheel and eccentric shafts.

  5. 5.The Guide Rod shafts – Made from steel drill rod.

  6. 6.The Bearing Blocks/Pedestals – These can be made in one piece or two pieces. Drawings are provided for both. A two piece bearing block/pedestal will make for easier assembly and alignment of the flywheel and

  7. 7.eccentric shafts. You have artistic license to decorate the outside of these blocks as you wish.

  8. 8.The Levers – Made of steel and bent per drawings. Tweaking may be required during assembly. The dimensions on the levers are critical for operation.

  9. 9.The Gears – Can be machined from scratch or purchased from Boston Gear or MSC.

  10. 10.The Clutch – The flywheel clutch provides one-way rotation of the FlyWheel and is a purchased item (Torington Bearing RC812208). Can be purchased from MSC.

  11. 11.The FlyWheel – Machined from steel. A suitable casting maybe substituted.

  12. 12.The Pawl Eccentric and the Valve Eccentric Assemblies – Special attention is required on these assemblies. These assemblies drive the fuel and exhaust system of the engine. When assembling the two eccentrics together with the eccentric bushing, the pawl eccentric is placed on top of the valve eccentric. The pawl eccentric is rotated 90 degrees clockwise to the valve eccentric. Once these are properly aligned, drill through the pinhole in the pawl eccentric into the valve eccentric...use the pawl pin to lock these eccentrics together.


The Pawl and the Pawl Ratchet Wheel are made of steel and need to be case hardened due to heavy wear. The Pawl Spring is critical to operation. It must have enough tension to raise the pawl so pawl will engage the pawl ratchet wheel. The dimensions for the pawl (and the level it mates with) are critical to ensure proper timing and engagement of the pawl with the pawl ratchet wheel. This engagement drives the valve assembly at the base of the engine. The pawl must release from the lever when the piston hits bottom. This engages the spring loaded pawl on the pawl ratchet wheel which causes the whole Eccentric assembly to rotate around the valve shaft. This action results in the valve lifting and allowing fuel into the engine. The valve then closes... contact is made between the valve and the Ignition contact point... the piston is fired to the top of the column...the exhaust valve is open... the power stroke of the engine occurs as the column cools (creating a vacuum) and “atmospheric pressure” drives the piston back to the base of the cylinder. The speed of the engine is regulated by controlling the release of the exhaust gases.


The Carburetor/Exhaust Valve Assembly – These parts must be  machined accurately...edges must be sharp, square, and free of burs. Surfaces must be flat and parallel. The Slide Valve must move smoothly and freely. The Port Face is silver soldered to the base column. It is then used as a guide to drill/tap for the Valve Studs. Be sure not to drill through into the cylinder bore when drilling and taping for the Valve Studs. The intake and exhaust ports are drilled through the port face and into the bore of the column. De-bur these holes on the inside of the cylinder.


The setting of the Slide Valve is similar to timing the valves in a modern day engine. The valve must be set to allow fuel into the engine at the right time, trigger the ignition to fire the engine, and then allow for release of the exhaust gases. The engine should be fully assembled except for the Slide Valve and the valve cover. Lift the rack high enough to clear the levers so the pawl will unlatch from the Ratchet Wheel. This will allow the FlyWheel and the shafts to spin freely. The high point of the Slide Valve Eccentric should be in the horizontal position with the high point toward the rack. Hold the FlyWheel to prevent the rack from going down and the shafts from turning. Screw the Yoke with Slide Valve attached up or down on the Valve Rod so the exhaust hole in the Slide Valve and the Port Face are aligned. This may take a little fiddling and screwing the Valve Rod up or down in the Eccentric Valve Strap to have proper adjustment at the Yoke end of the Valve Rod. Now you can install the Valve Cover, Springs, and nuts. Tighten the nuts only enough to apply light pressure on the Slide Valve. Apply only enough pressure to  prevent the Slide Valve from leaving the the Port Face when the engine is running.

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