The worlds smallest gasoline engine concept is 15 mm long, 5 mm wide and 3 mm tall, and is being developed at Cambridge and Birmingham Universities in the U.K. Below is an image of this micro engine taken whilst under development.

If this concept is successful, the micro engine is envisioned to be able to outlast today's NiCad and Li-ion battery cells by a proposed 20 times.  The power output of this engine is expected to be at  around eleven Watts, produced from  a speed of 50,000 r.p.m ( revolutions per minute)

At most, the engine could power and LCD watch for two years, from a single drop of lighter fuel...a thimble sized fuel cell could have it running for decades non stop.

It is thought that it would produce seven hundred times more energy than a conventional NiCad or Li-ion battery and could end up powering a laptop.

Scientists stated "We are looking at an industrial revolution happening in people's pockets. The breakthrough is an enormous step forward. Devices which need re- charging or new batteries are a problem but soon will be a thing of the past."

Of course, micro engines such as this could have a thousand and one applications for medical, military, robotic and general scientific research.  Micro engine research would probably be developed by large battery manufacturers as they would eventually replace cell batteries.

Charging today's batteries takes two thousand units of energy to produce one unit of power.  The micro gasoline engine would of course not need to be charged or recharged up with electricity...just a drop of gas.

Micro engines are not a new innovation, the  main problem with them is how to get rid of the heat that the little combustion engine would produce.  With the latest advances in thermo setting materials, such as poly carbon ceramics and silicon carbides, the heat can be dissipitated.

With the ongoing research by chemical. electrical and mechanical engineers these micro engines could soon be powering our devices in the not too distant future.


The worlds smallest working engine is currently a Wankel  type rotary engine, it was created at The College of Engineering, University of California, Berkeley, C.A, in the U.S.A. It is made from solid steel, with all steel working parts such as the piston and bearings. Below is an image of the engine with the side plate removed to show the rotary piston.


The engine runs on butane or propane and delivers power to light up a 2.5 watt light bulb, but the engineers at Berkeley Labs are working on a 'tuned-up' version to deliver an estimated 30 watts of electrical power. This would be ample to run moderate electrical appliances like a laptop computer.

This “mini engine” is also a prototype for a Berkeley labs proposal to create a microscopic engine chemically etched from silicon.

We are at the frontier of research into how to generate power using the smallest of components, ” said Carlos Fernandez-Pello, a mechanical engineering professor who developed the engine with the help of Kenji Miyaska of Fukui University in Japan, Berkeley post-doctoral researcher David Walther and graduate students Kelvin Fu, Aaron Knobloch and Fabian Martinez.


The worlds smallest steam engine is literally microscopic, built with nano technology or the ability to create objects at the atomic scale. The image above shows a steam engine built with nano technology, the engine is about five microns across. A human hair is about one hundred microns across, so this engine is very, very miniscule.

This steam engine was developed by Dr. Jeff Sniegowski at Sandia National Laboratories in Albuquerque, New Mexico, U.S.A.  It classes as the worlds smallest steam engine as it works like a full size one. There are three pistons that are run by steam created by water from a tiny reservoir.

A tiny electrical current boils the water in its tiny boiler to create steam which is then fed under pressure through the array of pistons which in turn push the pistons out.

When the electrical current is stopped the steam condenses back to its original state of water and the pistons retract. Repeating this process makes the engine run continually.

The engine has been built with the same technology that is used to build silicon chips and micro-processor components. This is basically done by photographing an image and etching the image onto photo sensitive material which is then reduced to a very small size on a silicon wafer.

The information on the photo-stat of course is still there, similar to micro-dots that the spies used to hide secret information.  These etchings are then done in layers to build up the device as a dimensional object.

When this is complete, the engine is a three dimensional working unit.  Its the appliance of science, but you need an electron microscope to see it!


Page created  August 24th 2007.   Updated January 11th 2013