Patent Portfolio for License:

Miniature Internal Combustion Engine Generator Patents for Sale    

Innovative motor-generator consists of a miniature linear engine coupled with a linear alternator.


The company has been developing its Miniature Internal Combustion Engine (MICE) generator technology to address the need for high energy density portable electric power. The MICE generator offers energy densities that are five to ten times higher than current rechargeable batteries, and therefore is an enabling technology for powered prostheses and other high power portable devices such as power tools. The company has demonstrated the ability to achieve very low levels of acoustic emissions and vibration from a packaged system.

This innovative motor-generator consists of a miniature linear engine coupled with a linear alternator. It takes advantage of the high energy content of hydrocarbon fuels while eliminating most of the parts found in a standard internal combustion engine-generator set. The basic MICE generator design, shown in the adjacent figure, consists of a two-stroke engine, a spring, and an alternator in a linearly oscillating configuration. MICE is inherently an electric power generator, since there is no mechanical linkage with which to extract power. Pure linear motion is ensured by the use of a unique double helix or multiple helix spring. The pure linear oscillation provides sliding motion with no side forces. The piston does not use rings to seal the combustion chamber, using instead a close fit between the piston and cylinder to hold the leakage to a small enough level that essentially no cycle penalty is incurred. The small amount of leakage, in fact, provides a hydrostatic bearing force to center the piston in the cylinder. Thus, the MICE generator has low frictional losses since there are no bearing surfaces having a direct load. The low friction characteristics and absence of stress generated by direct loads allow the MICE generator to operate at very high cycle speeds, leading to high energy and power density, particularly at smaller size scales. The pure linear motion, in addition to having low frictional losses, allows operation with a solid film lubricant alone in other words, no oil with a pressure-balanced cylinder design.

Primary Application of the Technology

The suitability of any power generation device for applications depends critically on factors beyond weight, energy density, cost, and such. Factors such as noise and vibration could render any power generating technology unusable if these were not reduced to a level compatible with the specific application. The company has identified effective approaches to manage all of the side effects issues of the MICE generator.

Competitive Advantage

Major differences exist, between the MICE generator and conventional engines. One key difference is that MICE is a free piston design that uses a spring for energy storage. A second major difference is that the MICE two stroke engine is designed to operate with a scavenging ratio less than unity, using HCCI (Homogeneous Charge Compression Ignition) combustion with glow plug assist as the mode of combustion. This gives the MICE generator its low emissions and high efficiency characteristics. Also, the MICE generator is a high Q system, operating at the resonant frequency of the spring-mass system with very low frictional losses.

The company has developed the MICE generator in three power ranges. The adjacent figure shows the 5 10 W MICE generator next to the 300 500 W MICE generator which is designed to use both light (propane, butane) and heavy (JP-8, diesel) fuels. An AA battery and ruler provide a dimensional reference. Extensive testing has been performed on the 300-500 W MICE generator using both propane and JP-8 fuels. The third size range, a 100 W MICE generator, has recently developed specifically for the powered prosthesis applications. The 100 W MICE generator was designed to operate with a butane or propane fuel cartridge.

Frequently Asked Questions

Technology Readiness Level: The technology is at the proof-of-concept for this powered prosthesis application at the 100 W level, and at the lab-prototype for general 300-500 W portable power applications. Commercialization funding is needed to take the MICE generator technology from proof-of-concept/lab prototype to a commercial product.

Additional Information

The company holds three US patents on the Miniature Internal Combustion Engine generator technology and application, and an additional patent is pending. In addition, the European patent on the MICE generator technology has been approved and is about to be issued.

Patent Summary

U.S. Patent Classes & Classifications Covered in this listing:

Class 290: Prime-Mover Dynamo Plants

Production and transmission of electric power and does not include any specific use to which the power is put.

Subclass 1A: Unitary plant

Class 123: Internal-Combustion Engines

Inventions relating to prime movers or engines in which a combustible material is burned within an inc losed space or chamber and the heat energy thus developed converted into work by permitting the resulting products of combustion to act upon and through mechanical powers, the engine in question including suitable mechanism whereby the functions above enumerated are continually and automatically carried out, and such engine being designed to communicate power to some machine or device exterior to itself. This class also includes separate parts of engines coming within the above definition and also subordinate elements designed for use with such engines, and incapable of use in the manner contemplated with other devices or in other relations.

Subclass 3: Generating plants
Subclass 46E: Electric generating means