X Mini Gasoline 70 cc Engine Prototype

LiquidPiston is currently developing and testing the X Mini, a power-dense, low-vibration, quiet,
70 cubic centimeter gasoline powered rotary four-stroke engine prototype. The compact engine
(4-pound core) has only two primary moving parts.
Download X Mini Brochure with Specifications

The X Mini is based on LiquidPiston’s patented thermodynamic cycle and engine architecture. To date, the X Mini prototype has demonstrated 3.5 horsepower (net indicated) at 10,000 RPM and the ability to run steady state with air-cooling.

When mature, the engine is expected to weigh 3 pounds, produce over 5 horsepower at up to 15,000 RPM, and be over 30 percent smaller and lighter than comparable four-stroke piston engines.

The X Mini prototype demonstrates that LiquidPiston’s innovative engine technology can scale down in size – prior prototypes focused on 40 and 70 HP designs – and is multi-fuel capable – able to run on gasoline (spark ignition), in addition to previously demonstrated diesel and JP-8 (compression ignition).

The X Mini will enable many small engine applications to be smaller, lighter, and quieter, including hand-held power equipment, lawn and garden equipment, portable generators, mopeds, unmanned aerial vehicles, robotics, marine power, range extenders, and auxiliary power units for boats, aviation and other vehicles. The engine’s improved noise, vibration and harshness (NVH) characteristics will also increase product performance, enhance operator comfort and prolong application life.

Prototype Demo Video

This video shows an early X Mini prototype running, in a speed sweep from 1000 to 6,000 RPM.

Combustion Demo Video – X Mini 70cc Gasoline Powered Prototype

This high speed video taken at 20,000 frames per second shows the combustion happening inside a LiquidPiston X Mini engine prototype. The engine cover was replaced with a special quartz cover in order to take the video. A spark plug is blocking part of the combustion chamber, but the remainder of the chamber is visible as the rotor expands, and it is clear how the spark-ignited flame propagates in this chamber.

LiquidPiston X Mini 70cc SI engine animation

This engine is the size of a grapefruit, weighs 4 pounds, and produces 3+ HP ! This video shows the internals of the engine, demonstrates the gas flow and implementation of the SI version of the High Efficiency Hybrid Cycle (HEHC)

LiquidPiston X-mini Powered Go-Kart

This video shows LiquidPiston’s novel 3-chambered rotary engine powering a small vehicle demonstrator (go-kart). This marks the first time an engine has been run outside of the lab, and is a big milestone for the company, as this engine required integrated cooling and control systems.