How does engine know when to spray fuel, let in air, compress air, and exhaust spent combustion product?
Obviously, there must be a certain timing for these processes to follow in order for diesel engine to work.
If fuel were to be injected when air inside cylinders is not sufficiently compressed, it will not ignite. Furthermore, if timing is not correct, some of unburned fuel may find their way out through exhaust and become lost.
Inefficient combustion takes place and power will be lost.
The many components of a diesel engine must work together properly, doing their function at correct sequence all time. If any component does not function as designed, engine will perform poorly or even stop completely.
The main moving components of a diesel engine, i.e. piston, connecting rod, crankshaft, fuel pump, exhaust valves and inlet valves are connected together through carefully designed gearing, cams, push rods, rocker arms, and sometimes drive chains.
Adjusting timing of various processes of a diesel combustion cycle involves adjustments to these linkages.
In small diesel engines, very little adjustments can be done. However in large diesel engines, each of these components can be adjusted for maximum efficiency.