Timing:

In the subsequent discussion of the diesel cycle it is significant to remember in mind the time frame in that each of the actions is needed to occur. Time is needed to move exhaust gas out of the cylinder and fresh air in to the cylinders, to compress the air, to inject fuel, and to burn the fuel. The crankshaft would be rotating at 35 revolutions, or 12,600 degrees, per second if a four-stroke diesel engine is running at a constant 2100 revolutions per minute (rpm). One stroke is finished in about 0.01429 seconds.