Greets; I have read a few speculations.., so here are some thoughts, and some facts, in brief, based on my personal experience(s).
1) Diesel engines can be run on propane, i.e., C3H8, or even better yet, scrubbed natural gas, i.e., CH4, (methane).., with some head changes, etc. Not something I have done to a diesel engine. However, I have adapted a gasoline engine to propane. C3H8, which at it's heart contains CH4 which means that the CH4 is the absolute base fuel. It/they; are under either low, or high pressure storage, and/or usage.
2) In regards to ignition under high heat, and/or pressures, I can only speak about CH4, which may indicate similar clues as to how C3H8 behaves in either a diesel, or gasoline engine. The cleaner CH4, (with less C's, and H's), will explode when pressurized into a containment containing any O2 at about 1,600 psi., "The Flash Point". Therefore CH4 introduced into say a oxy/ace, (O2/C2H2). tank must have the tank vacuumed firstly, meaning absolutely no other gas inside, i.e., regular atmosphere, i.e., air before attempting to fill with CH4 beyond the flash point pressures. None, nada, nyet.., or boom! The reason to go beyond the 1,600 psi, is in order to 'help' the methane to liquify, a process using extreme refrigeration, and or using another chemical liquid as a one tenth of volume sponge. This allows the gas to become a liquid, therefore more btu's can be stored. There are less BTU's in propane, than in gasoline. Thus, there is a 5% power reduction from the 'git-go. However, on the time line chart, the propane powered gasoline engine will last as long as a diesel, which is about 3 times longer in hours, or miles than a gasoline engine's internal combustion's excess of incomplete burn by-products, and carbon wash down.., all combining to more quickly break down the oil lubricant viscosity, and the carbon sanding down of bearing surfaces.
3) Propane runs as smooth as silk. At a 100k, propane will maintain a higher HP over the declining gasoline engine, as the propane engine is like new. It is simpler to convert a gasoline engine to propane, than a diesel, IMHO. However, as there are conversion kits available for gasoline/propane dual-fuel systems, (both carburetion/fuel-rail-throttle bodies), there may be some kits now available for the diesel/propane systems.., 'dunno.., lol, haven't 'googled' yet. Overall, I found the smoothness to further reduce downstream mechanical roughness, i.e., easier on drive train parts too. Just 2c.
