Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Car work for quantum mechanics

30.01.2002


A quantum afterburner extracts laser light from vehicle exhaust.


The last leap forward: Otto’s first four stroke engine of 1876.
Courtesy of Deutz Canada Inc.



The hot gases belching out of your car’s exhaust are not just useless waste. They are a laser waiting to happen, says physicist Marlan Scully1.

All you need to harness this potential, suggests Scully, of Texas A&M University in College Station, is a quantum afterburner. This hypothetical modification would use quantum mechanics to boost the engine’s efficiency by clawing back waste heat and turning it into useful energy - laser light.


Scully’s quantum soup-up would involve adding two new parts to an exhaust pipe: a laser and a maser (a kind of laser that emits microwaves rather than visible light). Both would produce radiation as soon as the number of high-energy molecules in the hot gas became abnormally large.

Normally, the higher the energy of excited molecules, the fewer of them there are. But in lasers, there is a population inversion - the gas becomes rich in excited molecules. Excited molecules then lose their energy by emitting it as light.

The quantum afterburner would rely on exhaust molecules being in three different states, like three rungs on an energy ladder. The maser would wring out energy from excited molecules on the second rung, sending them to the bottom rung. This depletion of the second rung would create a population inversion between it and the first rung that would produce laser emission.

In effect, says Scully, the maser would drain some heat from the exhaust gas so that the remainder could be extracted as useful laser emission. In a normal engine, all the heat in the exhaust is disregarded as useless.

Scully and others are now trying to build a real quantum engine, to probe the feasibility of his idea.

Work it

Engine efficiency is an old problem. The scientists who investigated it during the Industrial Revolution created the discipline called thermodynamics, which describes how heat flows from place to place.

In the early nineteenth century, the French engineer Nicholas Léonard Sadi Carnot calculated the maximum work available from an engine in which heating a gas through a cycle of expansion and contraction drives the motion of a piston.

Scully has taken a fresh look at the efficiency of such a cyclical process, not in a Carnot engine, but in an Otto engine. Devised in 1876 by Nikolaus Otto, this system forms the basis of today’s four-stroke internal-combustion engine.

In the Otto engine, a moving piston sucks fuel into a cylinder and then compresses it. The fuel is ignited and expands, pushing the piston outwards. The piston then expels the spent exhaust gases.

References

  1. Scully, M.O.Quantum afterburner: improving the efficiency of an ideal heat engine. Physical Review Letters, 88, 050602, (2002).


PHILIP BALL | © Nature News Service

More articles from Power and Electrical Engineering:

nachricht The role of Sodium for the Enhancement of Solar Cells
17.07.2018 | Max-Planck-Institut für Eisenforschung GmbH

nachricht Behavior-influencing policies are critical for mass market success of low carbon vehicles
17.07.2018 | International Institute for Applied Systems Analysis (IIASA)

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>