Joule Thief 101

[SeaMonkey]

That statement is for the most part not true.  Particularly with regard to NOx  emissions. 

Very often efficiency and emission reduction are at complete odds with each other.

Oxidized Nitrogen by-products are the result of
very high temperature combustion.  The techniques
for reducing combustion temperature while at the
same time increasing gaseous reaction volume are
well known.  It is possible to eliminate NOx, reduce CO,
reduce fuel consumption and thereby enhance engine
power and efficiency quite easily.  Aviation has been
doing it for decades.  Savvy motorists have also been
doing it for decades.

[Magluvin]

Anyway....

Was looking into the battery oscillation more.  With the new circuit a relatively fresh AA battery is ringing at about 15mhz. The voltage swings seem quite high, so I put a white led across the battery. Circuit is running without load leds. Only the led across the battery.

Mags

[picowatt]

Oxidized Nitrogen by-products are the result of
very high temperature combustion.  The techniques
for reducing combustion temperature while at the
same time increasing gaseous reaction volume are
well known.  It is possible to eliminate NOx, reduce CO,
reduce fuel consumption and thereby enhance engine
power and efficiency quite easily.  Aviation has been
doing it for decades.  Savvy motorists have also been
doing it for decades.

I was with you up to "enhance engine power".  There was a time when EGR was used for purposes not related to intentionally reducing emissions.  However, replacing a lot of inlet air or air/fuel mix with EGR to reduce NOx is not going to "enhance power".  As well, adding extra fuel to to keep the cats lit off or just having to deal with their added back pressure is not going to improve fuel economy.

Look at VW's recent diesel emissions debacle.  They illegally chose performance over reduced NOx emissions when the vehicle's software detected no emissions test was underway (mostly by decreasing EGR).

It is quite easy to improve the fuel economy or performance of a modern auto engine.  Lose the emissions related hardware and reprogram the ECM.  There is an entire aftermarket devoted to doing just that.  While it is illegal to do so in the US, many do it anyway (often under the guise of claiming off road use).

I would not want to own a modern diesel with a DPF.  Another consumable (DEF), additional exhaust back pressure, and even more fuel needed to burn off captured particulates during the DPF purge.  Talk about reduced performance and economy for the sake of reduced emissions.  Aftermarket DPF and EGR delete kits abound... (and of course are installed and used illegally)

Some of the emissions related gear has gotten better (for example, modern cats need less fuel (EGT) to keep them "lit").  But for the most part my statement stands.  Reducing the emissions produced by an ICE almost always means having to reduce performance, efficiency, or more to the point, fuel economy.

PW

[picowatt]

Now we get into the meat of the matter.   

When the 1K resistor across the LED is removed, the LED goes out.

But when I replace the resistor with a 2.2 uH inductor (DC resistance about 0.8 ohm) , the LED comes back on.

Without the 1K resistor there is no path for current to flow when the applied waveform is a negative voltage.  Without that current flow, the 1N4007 diodes never turn on.  Because they never turn on, there is no turn off delay to power the LED when the waveform transitions to a positive voltage.

This supports 1N4007 turn off delay time as being the reason the LED lit (as opposed to junction capacitance).

PW

[SeaMonkey]

...
Some of the emissions related gear has gotten better (for example, modern cats need less fuel (EGT) to keep them "lit").  But for the most part my statement stands.  Reducing the emissions produced by an ICE almost always means having to reduce performance, efficiency, or more to the point, fuel economy.

Your thinking is too recent and too modern.
The techniques I hinted at go back a long
way and are completely "legal."  In fact,
they are still in use today by many.  The
aviation industry uses a variant to boost
aircraft power when it is most needed.

Rudolf Gunnerman has devoted many years
to his project of maximizing engine efficiency
while minimizing harmful emissions.

It is very unfortunate that Corporate Love of
Money (and individual Love of Money as well)
have proven to be a nearly insurmountable
obstacle to the manufacture of clean and efficient
engines for the masses.