LiquidPiston has built functional proof-of-principle 70 and 40 hp diesel engineprototypes (x1, x2, and x4), which have demonstrated initial operatingcapabilities of the engine architecture.

These diesel engine prototypes, are capable of running for a short time at light load, and demonstrate compression ignition of diesel or JP-8 fuel, and net indicated efficiency of 33% (at light-load), which compares to ~30-40% efficiency in this size range of diesel engines at part-load. Intended as proof-of-principle demonstrators to show the engine is capable of running, X1 and X2 prototypes were designed without cooling systems. X4 improves prior designs by implementing a water-cooled engine block for extended operation and testing.

A standard 35 HP diesel engine (left)
next to LiquidPiston’s 40HP diesel engine (right)