As research and development has progressed the ideal configuration of the flash steam engine has evolved. Although the primary focus has been based on the Four Cycle Steam Engine (Otto Steam Engine). Direct Injection is the preferred method used to run these types of engines. The DI valve that's used in the applications features a variable lift mechanism, this is necessary in order to throttle such engines.

Initially very high pressure and or supercritical steam/water was injected into the engines. Even though high pressures are still used, the water does not contain super-critical energies, but is heated somewhat. As development has progressed a so-called "cold" water injection system is preferred. All of the original problems still apply, such as limited heating surface area of the piston cylinder and latent heat absorption barriers to the injected water.

With the first successful experimental engine running events, a densification factor was discovered. This is inherent to the four-cycle steam-engine configuration. So the 4-cycle engine aspired air and compressed it as the engines were run.

With this mechanism it is very easy to pull exhaust steam thru a super-heater on its way back to the intake port of the engine. Remember this is not a closed cycle, some of the exhaust steam escapes to a condenser that is open to atmosphere, the engine only draws as much steam as needed to achieve conservation, so this is not a regenerative concept. Regeneration would be the case, if the exhaust steam was heating a feed water circuit and this is not happening. Instead, the exhaust steam that's conserved by the process, remains steam and is not condensed. Alternately the steam is superheated by the external combustion chamber before its re-introduced to the engine thru the 4-cycle aspiration. Very similar in nature to a re-heating stage, but different since the steam technically returns to the primary expander, there is no secondary expander with this configuration.

In addition to classifying the engine as an Otto Cycle Steam Engine or a Flash Steam Engine, It may accurately be classified as a Desuperheating Engine as well. This because the injected water is intended to flash into steam, in the cylinder, as a result of several inherent mechanisms the engine system employs, this injected water comes into direct contact with superheated steam compressed inside the engine cylinder, where the injected water de-superheats such steam, and may do so with high frequency intervals continuously overtime. This is possible because upon every intake stroke a fresh supply of superheated steam is provided for that interval, enabling the power-pulse to occur once every 720° of crankshaft rotation for its required duration, generally 95° crank rotation, depending on the expansion factor. <>