Well, lets see how many "new" things that have come, I stated in the mechanics of the engine, and wasted sparkplugs, EFI, AND "the list goes on" is just not a mecanical part of the engine but ad ons as computer technolegy and electrics has evolved over the years. So READ what i write before you answer.

"I am a car mechanick and there have not been many new things to four strokes in the last 100 years, in the mechanic erea."

You say fuel injection= not a mecanical part in a 4-stroke engine. If we shall call it a mecanical part, i think that kugelfisher had a mecanical injection unit made in the 50`s. not 100 years old but not new. this was also used on aircrafts before the 50`s i think. It was modiefied slightly to be used in automobiles.

Forced induction of air= well again, turbo and compressor is about 90-100 years old. Roots made his compressor in abaout 1910 or so, turbos came around the same time and was used in WW 1 in aircrafts. When they reached high altitude they needed a way to get more air in to the sylinders because the density of air is less. Inventor of the turbocharger was someone cald bushi or buchi, something like that.

Adjsutable valvetiming been around for quite a while. They have even made camshafts with camlobes that are hydraulik adjusted. camlobes are not cast in the crankshaft but "loose" on an axle. how it works, i do not know. Ferrari has another system, they have cut different profile in the camshaftlobe and slides the camshaft axial to get different valve timing. how old this system am i am not shure of but it is not very new design. I think he variable valve timing is 30-40 years old. Maby not old enough or you.

Almoast evrything you find on a modern car engine, in the mechanical parts erea are old news, but "re-invented" or made a little diffrent to be of better use in our engines since it was not made for car engines in the begining.

and the list goes on!!!!