I wonder why all engines today use the standard 4 bar linkage when there is a really good option available in the "cartwright straight line mechanism" also know as the double crank mechanism. Refer to
for details on the mechanism.
I have also prepared a simple CAD based animation of the mechanism. This is given below.
What you can see here is a possible mechanism for an engine that is conveniently conventional & at the same time, there is no side thrust between the piston & the cylinder liner.
This will have good benefits in terms of
1) Mechanical efficiency
2) Good durability at very high speeds & loads
I believe that this will be the configuration of engines in the future.
Already, a couple of people have built such engines.
So what do you think of this system?