Since the idea of economy started in humanity’s mind, everybody wants to reduce the expenses, mostly on energy dependence. Nowadays, when hybrid cars and, generally, electric vehicles are starting to play a huge role in car industry, and electric technology is starting to get cheaper yearly, there still are scientists that get inspired by the old explosion engine principles, albeit they are being used for more than a hundred years and their power source is mainly based on fossil fuel.
The “free piston” engines, invented in the 1920s, are much more simple than regular 4-stroke engines, consisting mainly of two pistons, and one large cylinder, as you can see in the picture above. The sparks are ignited when the piston is nearing the top dead center gaining precious wasted time and thus maximizing efficiency. Preliminary theoretical research and experiments say that this kind of engine has over 50% efficiency, which is more than double of gasoline engines, and much more efficient than diesel ones. The drawing presented is more than self-explanatory.
The center of the rod that unites the two pistons is surrounded by coils, itself having attached magnets, to create electricity. That’s why it’s said that if this kind of motor could prove itself feasible enough to be built in future cars, it could provide power for the electric motors they have onboard.
I partially agree to this idea, because fuel cell technology is still cheap, and people would rather buy something cheaper at first, but there’s a second part: if you don’t buy hydrogen fuel cells, they are going to evolve even harder, and their prices are likely to remain at the same stage they are now – as prototypes for “future” cars.
It’s now generally agreed that electric motors will be the future of car movement, but the transition is very disputed among energy experts and companies on the one hand, and the final users, on the other hand. I think the best idea is to make the future vehicles as flexible as possible regarding the fuel type and the energy generating source. Like it has been done in programming to make it efficient, modularization is the key to cheap future development. I guess you get the picture by now.