To be blunt, running gargantuan compression ratios, say 15 to 1, and stoichiometric mixtures that run incredibly lean would have previously generated unacceptable amounts of heat. Now that eenergy can be harnessed. So if anything, the hydrocarbon strokes could exist simply to create as much heat as possible, and the water strokes could exist to capture it (this by injecting a great deal of water into the cylinder).

Besides the obvious teething problems of any new technology, the real limit would the the integrity of the block and head, which would have to withstand the pressures of huge compression ratios. Additionally, once we see a maturation of direct injection technology, dual injectors could supply fuel and water. The only problem I see unaddressed here is how to capture and segregate the two different types of exhaust, particularly the capturing of steam for cabin heating purposes and condensation. This is, of course, wholly surmountable. Many applicable solutions exist; technologies from steam locomotives, turbines – very little will have to be conjured from scratch.

In short, the advantage we’re seeing here is that heat has now, in this engine design, become a desirable and beneficial characteristic of engines. Running 13, 14 to 1 compression ratios has always been possible, until the engine warms up and pinging begins, but now we’ve found a sustainable way to capture that power under running conditions. Ultra-lean mixtures and super-high compression ratios open new vistas of internal combustion engines.