Part of Phase 5: Rebuilding Technology. The overview is Internal Combustion; its sister domain is Refrigeration.
An engine is a refrigerator run backwards. It takes heat from a hot source, turns part of it into work and rejects the rest; a refrigerator is fed work and moves heat from cold to hot. The same kind of cylinder, piston and valves appear in both, and the temperature arithmetic of one carries over to the other, which is why the refrigeration domain’s compressor pages and this domain’s piston pages describe such similar parts.
The domain begins with the theory of the cycle and the spark-ignition and compression-ignition forms, then the parts that make up an engine: block, piston, crankshaft and valves. Fuels are a large part of the story for a settlement without petroleum: wood gas from a gasifier, ethanol from fermentation and distillation, and biodiesel from the neighbouring chemistry domain. Two standing warnings run through the fuel pages. Producer gas is about a fifth carbon monoxide, which has no smell and kills gasifier operators, and the gas is proved at a flare lit before it arrives and never with a flame at a pipe mouth. Fuel ethanol is not drink: methanol runs through the whole distillation, so a foreshots cut is a flavour step and no volume rule makes a home distillate safe to drink.
The rest of the domain covers the systems around the engine: carburetion, ignition, cooling, lubrication, and the clutch and gearbox that connect it to a load. Recalled figures that are not taken from the overview are marked as recalled in the pages that use them, and no tolerance or clearance is given where none is sourced.
Cycle Theory
How heat becomes work, and how the spark and compression forms differ.
Engine Parts
The casting, the moving parts in the bore, the shaft and the valves.
Fuels And Their Delivery
Making and metering the fuel, with the carbon monoxide and ethanol warnings.
Ignition
Producing the spark and timing it.
Cooling And Lubrication
Carrying off the heat and keeping the metal apart.
Drive To The Load
Connecting the engine to what it must turn.