Here’s the ultimate expression of engine downsizing: a single atom that generates the mass equivalent heat of a typical car engine.
According to an article in Science magazine and numerous news reports, German scientists have constructed single-atom heat engine that is believed to be the smallest ever on record. A heat engine is one that converts thermal energy into mechanical energy that can perform work.
This particular engine was achieved by subjecting a calcium ion to two different temperatures: heat from an electric field and cooling from a laser beam. The ion was trapped and could only move along one axis, and the temperature difference generated motion along that axis–similar to the motion of a piston.
One of the scientists explains the conditions necessary: “We need electronics with very low noise [interference], a camera with the shortest exposure times (700 nanoseconds), very good vacuum conditions, high control of the electric fields in the trap, and a high quality laser system,” says Dr. Johannes Robnagel.
Officials say the engine’s efficiency is only .28 percent, meaning that not even one percent of the total energy is converted to useful work. Average car engines are around 20 to 30 percent. Formula 1 engines are approaching 50 percent. The actual energy output of the single-atom engine was listed in watts at 3.4 multiplied by 10 to negative 22 power–which means there are a helluva lot of zeros after the decimal point, so the actual equivalent horsepower is hardly measurable. But if enough atom engines could be strung together to weigh the same as a typical aluminum V8 at around 400 pounds, then the power output would be comparable, say scientists.
The whole point of this exercise is to power possible nanotechnologies. An atom engine may be useful in applied and theoretical physics but it’s unlikely it will ever see consumer use. However, researchers may discover new thermodynamic principles that could advance other forms of heat engines.