Comments by "Keit Hammleter" (@keithammleter3824) on "All about the Taurozzi Pendulum Engine 🧠 and what happend to it🤯" video.
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The fact that it was not put into production by anybody after the patent expired should tell you something.
The fact is - it is a dumb way to make an engine. It solves a problem that isn't a problem, and it can't be made on normal block boring and honing machinery.
Any one who has completed the first year of an engineering degree can tell you why. In my first year, we had to do assignments on the losses in gasoline engines. Mechanical friction losses (not counting things like water pumps) account for less than 5% of the total. Most of it is in the bearings - the friction loss between pistons and cylinder walls is just a part of the 5%. So there is not much scope for making a noticeable improvement.
There is a rule of thumb with modern car-type gasoline engines: 30% of the fuel energy is converted to mechanical energy available at the flywheel, 30% is lost to atmosphere via the exhaust, 30% is lost to atmosphere via the coolant and radiator (this includes bearing and piston friction loss), and the remaining 10% is lost in the oil pump, water pump, fan, and turning the alternator.
The lube oil isn't just for eliminating mechanical rubbing - it is for cooling the pistons as well. Clearly, combustion gasses are in contact with the piston - the piston must get rid of considerable heat somehow. It does so by conducting it to the cylinder walls via the oil film between the piston skirt and the cylinder wall and thus into the coolant. In turbo diesels, that is insufficient, so oil is sprayed upwards onto the underside of the piston as well.
So if this turkey thinks he can reduce oil supply to the piston he is deluding himself.
Anyone who rebuilds worn engines for a living can tell you that cylinder bore wear is mostly not due to mechanical wear. It is due to sulphur in the fuel being converted to sulphuric acid in the combustion process. It occurs fairly evenly around the cylinder. Since the advent of low sulphur fuels some years ago, cylinder bore wear has been markedly reduced.
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@keithpeterson6108 : My other post was in response to your post claiming the crank is past "TDC" when the piston is at TDC.
Offsetting the cylinder from the crankshaft centre line is sometimes done as it changes the percentage of time the cylinder is in power stroke, but it makes almost negligible difference to engine performance or friction.
You have a misconception about how the heat energy in the burnt gases is converted into mechanical energy. It is done by gas expansion as the piston goes down - the fact that the pressure cannot rotate the crankshaft at TDC is of no importance. You might like to look up the "standard air cycle" - a mathematical model taught to engineering students as it explains why raising the compression ratio improves performance. It assumes combustion occurs instantaneously at TDC and that no heat is lost during expansion. Neither is completely true of course, but are both approximately true.
The short combustion time (mostly within a few degrees of TDC) is analogous to the "cut off" in a reciprocating steam engine. In a steam engine you get maximum efficiency when the steam valve opening time is kept within a few degrees of TDC, so that power is produced by expansion and not boiler pressure. This is a fact not often known except by engineers, but you can look up "cut-off" for yourself, and if you do, you will understand why arranging for crank leverage at TDC is not a good idea.
(Actually, in steam railway engines, the cutoff (ie valve opening time) is made variable. On starting off, the driver lengthens the cutoff - this increases torque for starting due to the extension of time piston sees full boiler pressure, but it considerably reduces efficiency, so as the train builds up speed, the driver shortens the cutoff, reducing steam consumption and thus fuel.)
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