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Why Pistons Are Poor Expanders

The illustration above highlights the benefits of the Vengeance Vane & Rotor expander design over the traditional piston & crank design. For simplicity, a piston expander with a 1:1 bore-to-stroke ratio (bore diameter = vertical stroke length) is used as a benchmark. Modern piston engines/expanders may vary slightly from this ratio but can never come close to the incredible torque of the Vengeance design with the same pressure input.

If you study the difference between the forces acting on the Piston and on the Vanes under equal pressure, you will notice there is much more force acting on the piston and crank while providing much less torque. This is a major flaw in the piston & crank expander design and a tremendous waste of energy.

The Vengeance engine size depicted above is less than 1/2 the size of an equal displacement V-8 Piston 4-stroke internal combustion engine and smaller than an equal displacement 4-cylinder 2-stroke engine or expander. Other Vengeance designs can deliver more than double the torque.

More Advantages Over Pistons

  • High power-to-weight ratio
  • Less friction
  • Low operating and maintenance costs
  • Low part count
  • Low manufacturing costs
  • Low noise & vibration
  • Higher efficiency
  • Multi-fuel capability
  • Does not require oil for lubrication

Advantages Over Conventional Gas & Steam Turbines

Conventional Rankine cycle/steam turbines are designed to run at maximum efficiency at speeds so high that any condensate droplets forming downstream in the exhaust section can lead to erosion and catastrophic damage to the blades. For this reason, more heat is added to ensure the vapor remains above 90% dryness. Some turbines add more than one re-heat stage to “zig-zag” to the right of the Dry Saturated Vapor Line. The extra heat and equipment added for superheating comes with a heavy price tag. Furthermore, in a closed-loop system, any residual superheat will have to be dealt with in the condenser. This also increases the size, cost and loading of the condensing unit.

The Vengeance Expander design allows more expansion, going deeper into the wet vapor region as it can tolerate high condensate formation. In fact, the Vengeance design can operate as an excellent hydraulic motor or pump. Allowing more expansion decreases exhaust pressure and temperature, putting less strain on the condensers and increases net system efficiency. It also allows for more efficient use of low heat and low pressure “wet steam” boilers and pressurized refrigerant-driven Organic Rankine Cycle (ORC) heat exchanger/evaporator systems.

More Advantages Over Turbines

  • Comparatively high electric efficiency for small-scale CHP units (up to 1Megawatt range)
  • Excellent partial-load efficiency over a wide range of load conditions
  • Runs efficiently in both back-pressure and condensing turbine modes
  • Load fluctuations between 10% and 100% of nominal electric power production are no problem
  • Not sensitive to steam quality or flow fluctuations
  • No high velocity steam nozzles to clog or clean periodically
  • Rapid stop and start times
  • Water droplets in steam from boiler malfunctions or fuel quality changes pose no threat
  • Fully automatic operation and easy handling saves staff costs
  • Compact size, rugged construction, easy setup, low maintenance costs
  • No isolated anti-vibration concrete pad needed
  • Does not require oil for lubrication

Limitless Applications

  • Automotive: Cars, Trucks, Vans, Motorcycles, SUVs
  • Marine: Powerboats, Pleasure Boats, Super Yachts, Cruise Ships, Ocean Freighters
  • Aerospace: Propeller Driven Aircraft, Helicopters, Heavy Lifting
  • Military: All Terrain Vehicles, Trucks, Tanks, Utility Vehicles, Amphibious Vehicles, UAVs, Combat Boats
  • Public: Freight and Passenger Trains, Busses
  • Recreational: Snowmobiles, Jet Skis, All Terrain Vehicles, Motor Homes, Go Carts
  • Domestic: Lawn & Garden Equipment, Pumps, Generators, Compressors
  • Industrial: Construction, Agriculture, Forestry, Mining, Drilling, Portable & Stationary Power Generation
  • Environmental: Waste Heat Recovery, Green Power Generation