What is difference between two stroke and four stroke diesel engine?

engine is a type of internal combustion engine which completes a power cycle with two strokes (up and down movements) of the piston during only one crankshaft revolution. This is in contrast to a "four-stroke engine", which requires four strokes of the piston to complete a power cycle.

The engine operates in 4 phases: (aspiration, compression, burst, exhaust).The 4-stroke makes one at a time, so: the aspiration valve opens and with the 1st downhill to the Lower Dead Point (PMI) the vacuum created sucks air and gasoline inside the cylinder (this is the aspiration ), then the piston starts to ascend to the Upper Dead Point (PMS) and with the intake valves and closed valves compresses the mixture (compression), the spark blast occurs immediately and then the mixture burns increases by volume pushing again the piston to the PMI (outbreak), the piston once reached the PMI starts to rise and at this point opens the exhaust valve that evacuates the exhaust gases from the cylinder (exhaust) ...these are the four phases that make a 4-stroke .. so the 4t engine has 1 useful phase and 3 phases where the piston drags, losing a lot of energy.The 2times instead of these four phases group them into two groups (aspiration-compression, expansion-exhaust).the two times have no suction valves, but the slots on the cylinder walls (not on the head as in the 4t) and the piston is the same to open and close these slits

two stroke are those engine  which are completed their  every stroke in to a powr stroke but in four syroke every second stroke is powr stroke