You talk about basically "common sense" when what you are really talking about is "assumption".
You're doing 40 mph down a straight road on a motorcycle, you want to turn right, which way do you turn the handlebars?
common sense, even from very experienced riders, will say "right"
the correct answer is "left"
motorcycles don't steer by changing the steering geometry and everything else follows suit, motorcycles steer by precessing the flywheel that is the front wheel, and allowing the reaction from that to change the steering geometry.
Just cos something looks like it makes sense doesn't mean you're right.
No amount of any mechanical experience in one field will make you an expert in any other, and your practical tractor glow plug example is a classic.
repeat after me, as many times as required, while slapping yourself in the face to help the lesson sink home.
CORRELATION DOES NOT EQUAL CAUSATION
you cannot build a logical argument upon a basis of correlation with a structure of supposition, that's called bullshitting.
start slapping yourself in the face again, and repeat the following.
COMPRESSION IGNITION ENGINE.
got that?
now I can tell FOR A FACT from what you've been saying that you do not understand even the basics of this, so, since your latest reply isn't so insulting, I'll explain in simple terms.
imagine a theoretical cylinder, made of a material that is 100% impervious to gas, is 100% friction free, is 100% super thermal insulator, is 100% super electrical insulator, and has a piston of the same properties, with a 100% perfect gas seal, we can add an equally impossible temperature probe that absorbs zero thermal energy, and a ditto pressure gauge, and a force transducer under the piston.
this 100% theoretical and 100% physically impossible device is your adiabatic cylinder / engine / compressor.
99.999% adiabatic is like being 99.999% not pregnant.
if you look at the (analogue) pressure gauge while you drive the piston up the cylinder you'll see the pressure rise, Boyle / Charles / Dalton et al, did a lot of work on this, and the gas will "heat up" which means the electrons move into higher orbits and thus you get more "energy" and more free electrons.
You will find that for each fuel, diesel in our case, there is a point at which the gas is just energetic enough to ignite the fuel and make it burn progressively, draw a line of the gauge, you'll also find that there is a point at which the gas is just energetic enough to ignite ALL of the fuel simultaneously, and you have an explosion, and you will find that these two lines are, compared to the angle the pointer on the gauge has swept through from atmospheric pressure, very, very, very close together.
COMPRESSION IGNITION ENGINE.
repeat our experiment, but move the piston up at twice the speed.
in our THEORETICAL adiabatic engine there is no change in pressures and temperatures, but the time interval between pressure hitting ignition point and explosion point just got cut in half.
COMPRESSION IGNITION ENGINE.
the trick is to have JUST ENOUGH compression cranking cold to cause ignition, because you need ALL the headroom you can get in the very small margin to run full load and max RPM without getting to the EXPLOSION point.
In a REAL engine you have the metal engine cylinder, piston and head absorbing free electrons, the slower the compression event duration, the more time there is to absorb them and the harder it is to get ignition. The colder the metal, the more free electrons it will absorb (and alloy absorbs a lot more than cast iron, hence alloy heads etc)
In a REAL engine you have coefficients of thermal expansion, so the slower the compression event the more blowby you get, plus the colder the metal the more blowby you get. The more blowby you get the less compression you get, and the less compression you get the less energetic the gas and less free electrons.
The faster you crank, the less time there is for blowby, and for absorbtion of free electrons, so anything that slows cranking, like a thick cold lube and a cold battery, gives you less compression and less free electrons.
(incidentally, de-compression most certainly DOES happen, big time, inside a compressor, why else do you thing diving compressors are three stage......)
also, you don't have to use heat of compression to heat the whole engine, iron, steel and alloy are not superconductors, it takes TIME for heat energy to flow through them, if it didn't, oxy acetylene cutting wouldn't work, fact is it does, so you CAN heat the few thou at the surface of a cylinder, piston and head, quite significantly..... don't believe me, get a bycicle pump, jam your thumb REAL hard over the end and give it one good fast pump.
only the surface, less than a thou, much much less than a thou, we are talking a square foot of kitchen foil mass of metal, has to be heated in order to raise it's electron / energy, thus creating a much shallower energy slope between it and our compressed and excited gas, this significantly reducing the energy transfer and loss to the gas. It doesn't take much energy, from compression, to flash heat that much metal, but crank slow enough and the heat will have dissipated by the next compression event.
the old rule of thumb was 75% of the energy in a starter motor went into compressing the gas, assuming a well serviced and within spec engine, and 3kw / 4 bhp is really a very very ordinary starter motor power, specced for car engines of about 500 cc per cylinder, not the 1400 of a lister cs 6/1
BTW, lit cigarettes will most definitely ignite gasoline, diesel not, not if it is cold and pooled, gasoline, yes....
==========================
back to your bloody tractor and hairdryer
CORRELATION DOES NOT EQUAL CAUSATION
4 fat bastards stood on the ice on a frozen pond, skinny ten year old kid walks up to them, ice breaks and all five go through.
the straw that broke the camel's back
that one skinny kid and that one straw did not do the trick, in both cases is was so close that it only took a tiny bit to trip over the tipping point into a different state.
the old saying "if it starts from cold there ain't much wrong with it" for a diesel understands all this, there is a VERY NARROW WINDOW of the actual time/duration of the compression event and losses due to blowby and free electron / energy absorbtion, which encompasses everything from just igniting the mixture to exploding it, there is a HUGE area BEFORE that window and a HUGE area AFTER that window, and neither one is any use.
I can cite you actual examples that I have witnessed, of HOT diesel engines that would not start, starting when a fine mist of water from a pressure washer was sprayed over the intake, by YOUR logic I should be claiming that water is what starts a diesel.
"A person can be very good at something still be wrong about why it works. "
Yeah, but I'm not wrong, cold steel is at the root of starting a diesel, everything, but everything, stems FROM the cold steel, the temperature of the ambient air is irellevant.........
standard diesel needs to be injected into air compressed to a temperature of 725 farenheit / 385 celcius, air at below freezing may SOUND like it puts the starting point further away, but cold air is denser, so you get roundabouts and swings, the real killer for REALLY cold air is when all the moisture has been frozen out of suspension, this very cold, very dry air, is less dense....
people also fuck up looking up the "flash point" of fuels, flash point is where you can get SOME combustion, for an engine to START you need to know the "fire point" of the fuel, which is nothing like the flash point.
so, one more time
COMPRESSION IGNITION ENGINE
and
CORRELATION DOES NOT EQUAL CAUSATION
just like turning the motorcycle bars left to go right, the cold steel is all that counts in starting a cold engine.
once you grep this you will never have a problem maintaining and engine in good order and thus starting "on the button"
until you grep this you will always be making excuses about why your engines do not start on the button 100% of the time.
