Smithsonian museums continue to be closed to support the effort to contain the spread of COVID-19. Read a message from our director, and check our website and social media for updates.

Wiegand’s Patent Model of a Gas Engine – ca 1864

Wiegand’s Patent Model of a Gas Engine – ca 1864

<< >>
Usage conditions apply
This model was filed with the application to the U.S. Patent Office for Patent Number 44,572 issued to S. Lloyd Wiegand of Philadelphia, Pennsylvania on October 4, 1864. Mr. Wiegand’s patent was for improvements in gas engines. Claimed improvements included: protection against the buildup of carbon deposits on the piston and cylinder; more accurate and fuel-efficient speed control; and a lower cost and higher durability construction.
Mr. Wiegand’s engine was designed to use “illuminating gas” which was a coal based product used for gas lighting. Due to inefficiency in combining the gas and air, carbon deposits were left on the surfaces of the combustion chambers. This damaged the seals between the cylinders and pistons resulting in leakage and reduced power. The patent called for a fluid to be injected into the cylinders via channels near the seals. The fluid would loosen and eject the carbon through the exhaust.
To improve the speed regulation and fuel-efficiency of the engine, Mr. Wiegand varied the timing of the intake valves. A shaft governor was included in one of the engine’s two flywheels, and this was coupled to a mechanism that adjusted the angle of the cam which opened and closed the valve. If the engine exceeded its desired speed, the cam adjustment would shorten the time the intake valve was open. The reduction in the amount of fuel entering the engine soon slowed it.
A search of available literature did not reveal any practical use of the patent. Shortly after Mr. Wiegand’s patent, N. A. Otto and others patented advances in gas engine such as compressing the fuel-air mixture prior to combustion and the introduction of the four stroke engine design.
The model as shown in the image illustrates all of the key elements of the patent except for the internal details of the valves and cylinders. It is constructed of metal. Diagrams showing the complete design can be found in the patent document online (
Currently not on view
Object Name
gas engine, model
patent model, engine, gas
date made
patent date
Weigand, S. Lloyd
Wiegand, S. Lloyd
place made
United States: Pennsylvania, Philadelphia
associated place
United States: Pennsylvania, Philadelphia
overall - from catalog card: 72 in x 7 1/2 in x 10 in; 182.88 cm x 19.05 cm x 25.4 cm
flywheels - from catalog card: 7 1/2 in; x 19.05 cm
overall: 11 7/8 in x 11 in x 7 3/8 in; 30.1625 cm x 27.94 cm x 18.7325 cm
ID Number
accession number
catalog number
patent number
Patent Models
Internal Combustion
See more items in
Work and Industry: Mechanical and Civil Engineering
Patent Models
Engineering, Building, and Architecture
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.


Add a comment about this object