We find ourselves in the year 1882 and Otto's patents are still valid. Thus, the Atkinson-engine can be considered as a circumvention of these patents. If one demotes the crankshaft on the left to a to a back and forth moving linkage and then imagines this to be on the right, then in a round about way, one could arrive at the two-stroke engine, which completes a complete working cycle in one revolution.
It's very likely however, that by doing this, one would be doing James Atkinson an injustice, after all, he did achieve, shown here in a simplified form, that the intake- and compression stroke are a good deal shorter than the combustion- and exhaust stroke. The basic idea is, to be able to exploit the inherent energy in the combustion mixture more effectively.
So the compression period is shorter than the expension period. Thus, the combusting mixture can better transfer it's kinetic energy to the piston on it's way down to BDC. The result is a more effective exploitation of the fuel. There is however, one condition that must be given,a consistently high compression ratio. 12/13
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