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 Solar-to-fuel system recycles CO2 to make ethanol and ethylene
19.09.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht A simple additive to improve film quality
19.09.2017 | King Abdullah University of Science & Technology (KAUST)

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: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

Im Focus: Artificial Enzymes for Hydrogen Conversion

Scientists from the MPI for Chemical Energy Conversion report in the first issue of the new journal JOULE.

Cell Press has just released the first issue of Joule, a new journal dedicated to sustainable energy research. In this issue James Birrell, Olaf Rüdiger,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

New quantum phenomena in graphene superlattices

19.09.2017 | Physics and Astronomy

A simple additive to improve film quality

19.09.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>