This is a three cylinder version of my new engine design. It has a closed crank case and can be pressurized. Its coaxial body allows for lots of outer surface area which is ideal for cooling. The hot caps at one end and the shaft exiting from the other makes this design a very attractive and easy to implement alternative.
This single cylinder version below uses a flat cam. The cam, like the one shown above, has two cam grooves however in this engine the cam also acts as a flywheel. This single cylinder version is an atmospheric engine, (it has no sealed crankcase and cannot be pressurized). This engine is hooked to a small dynamo and can generate about 25 watts of shaft power and about 12 watts of electricity. This very simple design is easy to manufacture and is currently setup to produce a perfect sinusoidal motion. This engine has a 1 inch displacer stroke and a 3/4 inch compression piston stroke. The stroke, dwell and the phase angle can be infinitely set.
Below are the patent drawings.
This Stirling device patent covers the overall construction and drive mechanism of a compact Stirling cycle engine or heat pump.
The modern Stirling Engine is a clean running and efficient engine. This is because the heat fueling the device is supplied to the outer surface of a portion of the engine. Thus carbon contamination or other combustion contaminants can be eliminated in the engine because the combustion never enters the engine. Only heat enters the engine via the engines heat exchanger. The external combustion aspect enables a Stirling Engine to operate equally well on multiple types of fuel, such as natural gas, propane, gasoline, diesel, bio-fuels, or even heat from the sun. Also, because a Stirling engine operates with a closed cycle, a pressurized Stirling can perform well at any atmospheric pressure or even in a vacuum.
Quiet operation of the Stirling Engine is one of the engine's most valuable features. Many Stirling engines are balanced by their nature, and since the fuel is burned slowly and constantly outside of the engine, there are no loud explosions so no muffler is required and there are no harsh vibrations.
A Stirling cycle is truly reversable, and many engines can be used as a heat pump when driven by a motor or another Stirling engine. This allows them to be used for refrigeration and even cryo-cooling using absolutely no CFCs.
My patented Stirling design has the following advantages over other currently available Stirling cycle devices:
1. Very compact, light weight and rigid drive mechanism that is easy to encapsulate for pressurization.
2. Easy to manufacture, low cost parts. No forgings of crankshafts or expensive gear components.
3. Very well thought out, practical, and cost effective coaxial layout construction. As Stirlings go, this one is very easy to assemble and work on if needed. It is assembled somewhat like a flashlight where the components can be installed or removed from a single end.
4. Infinitely setable phase angle, dwell, slope and stroke of pistons. This allows the engine to take the most advantage of the Stirling Cycle. No compromising for less than optimum phase angle or crank limited sinusoidal piston control.
5. Accommodating to any number of cylinders from 1 to however many you cluster around the coaxial drive cam. 6 seems like a practical maximum number of cylinders for this engine design however more could be employed. Most multi cylinder engines rely on a square four configuration which also limits them to a 90 degree phase angle between cylinders. I believe one of the greatest advantages with my design is not that you can go with more cylinders, but that you can go with fewer. Imagine a perfectly well balanced 2 or 3 cylinder engine in a solar application. Fewer cylinders can provide for a light weight, lower cost to manufacture Stirling engine. Also, this design would allow a line of engines to be manufactured using common cylinder and piston components in whatever cylinder number is needed for a desired power output. Again, a cost savings.
6. Rotary to linear motion from the cam mechanism eliminates any side load forces on the pistons.
7. Mechanically counter balanced from 2 cylinders up.
8. When used in a single cylinder configuration the design can employ a face cam or a barrel cam to control piston motion. The face cam also functions as a flywheel in the single cylinder configuration and can be counter balanced if needed.
9. Great potential for use as a prime mover or in a heat pump application. The prototypes have been tested for use as both engines and heat pumps.
Here a view of the barrel cam drive and two pistons from a single cylinder of a two cylinder version of the engine. Note that the cam has two grooves. One for the displacer and the other for the compression piston. The radial positioning of the grooves in relation to one another will determine phase angle of the engine and can be infinitely set. The grooves radial positioning in relation to each other will also determine the direction in which the engine will operate. As can be seen in the pictures below the cam has been made from a plastic material. The use of plastics in this Stirling drive allows for greatly reduced manufacturing costs over other drive designs.
This drive design was meant to be used with a beta type Stirling engine however it could also be employed with an alpha or gamma type Stirling. The beta type Stirling is constructed with the power piston and the displacer residing in the same cylinder. I chose to work with the beta type of Stirling mostly due to the fact that is has a higher compression ratio than either the gamma or alpha type Stirlings which is better for power. I have also worked extensively on the air circuit portion of this engine and will make all of that information available to licensees of this patent. I am open to either exclusive or non exclusive licensing agreement. Please contact me for further details.
I have been developing Stirling engines for 20 years and have 3 patents pertaining to Stirling devices. It is my belief that this design, which I like to refer to as my "Double Cam Stirling" is my best work and has the greatest potential for success as a mass produced Stirling device. This engine has been prototyped in 1, 2 and 3 cylinder configurations. I have included a patent drawing elsewhere on this page of my engine design in a 2 cylinder configuration. Please see my patent linked elsewhere on this page or contact me for further information.
Here is a frost covered heat exchanger of my atmospheric Stirling, being driven by an electric motor and run as a heat pump.
Being able to frost up an atmospheric engine like this speaks very well for the engines air circuit and compression. My hot caps and cold volumes contain arrays of passages inside along with sufficient annular regenerators.
This page was last updated on: September 26, 2011
(if image is not clear for you click on image for larger view)