I searched for the engine briefly, and found no mention of anyone thinking of this.
This post comes from this comment of mine.
In my original comment, I note that I immediately think the strain would blow the entire thing a part.
What are your reasons of why you think would not work, or why no one has tried, or maybe you know someone who did try?
Note, Not the size of a car. More like the size of a cargo ships diesel engine. (“Wärtsilä-Sulzer RTA96-C” as an example)
Imagined design. Original Post
Get this if you put enough matter in one spot the mass of the matter acts as the piston compressing the material until it begins fusing enough to resist the inward pressure. This lasts as long as there are enough fuse-able materials in the mix, be aware they can get a little unstable when fuel gets low.