Why the timings of combustion are important in a four stroke engines?

If we take for example an internal combustion four stroke engine its basic design is almost the same as about a century ago since its invention but one thing is certain that the valve timing & ignition timing are extremely important for burning the fuel liquid or gas in an efficient manner.

Variable Valve Timing (V.V.T), Multi point electronic fuel injection( M.P.E.F.I) are few of the latest innovations but one thing is sure that the internal combustion engine efficiency did not ever went up the mark of45% maximum with respect to fuel spent and rest of about55% goes in a form of heat dissipation or a waste heat recovery system has to be installed to get an efficiency of86% to90% or even more in some cases.

The whole mechanism of engine lies on timing of combustion. The turning moment is maximum during the power stroke. The turning moment produced in this stroke is required to be distributed for the remaining strokes. For example:- The timing for a4 cylinder engine is 1-3-4-2.

It implies the power stroke will first happen in1st cylinder and then in3rd cylinder. After the power stroke happens in3rd cylinder, it moves to4th cylinder and then to2nd cylinder. If there is any delay in ignition timings, then it decreases the life of the engine.