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Rotapower - The engine of the future

Rotary principle

How does a Rotapower rotary engine work?

In the traditional reciprocating piston engine, which has between 25 and 32 critical parts, the cylinder performs all four tasks: intake, compression, combustion and exhaust. In the Rotapower engine, the same four tasks are performed but by a triangular rotor fixed on its crankshaft in such a way that as it revolves inside its oval housing it describes a figure of 8 movement. The same four tasks happen in their own part of the cylinder housing but the rotor functions as both the piston and valves. With only 3 moving parts. no valves and no reciprocating parts, there is no vibration.

Fundamental hardware differences between a 4-stroke piston and a Wankel rotary

  • The Rotor replaces the piston engine's piston.
  • The Eccentric Shaft replaces the piston engine's crankshaft and connecting rods.
  • The Rotor Housing replaces the piston engine's cylinder.

Intake and Exhaust Ports in the housings replace valves, camshafts, rocker arms, springs, lifter rods, and timing belts.

4-Stroke Piston vs. 4-Stroke Rotary


Freedom's Rotapower engine has all the inherent advantages of existing Wankel-type rotary engines. In addition, it improves the Wankel-type engine performance as follows:

Emissions and fuel consumption
Uses our proprietary low cost lean burn combustion process together with our patented combustion surface coating and pre-heated incoming fuel-air charge to greatly reduce both emissions and fuel consumption. This technology has the potential to eliminate both the lubrication and cooling systems.

Long engine life in a low-cost design
Uses a new proprietary rotor and rotor cooling technology to reduce rotor weight and related mechanical stresses throughout the engine. Uses new apex seal material and proprietary plasma sprayed internal coatings.

Maximum power with minimum weight and size
Uses our proprietary porting design and advanced component development to generate twice as much power for its weight as most four-stroke competitors.

Modular design allows low cost power growth
One- and two-rotor versions of the Rotapower 650 Series engine provide scalable power for applications with requirements from 75 to 150 horsepower.

Ability to operate on any fuel
Proprietary technology developed to lower emissions and fuel consumption also allows the use of any type fuel with modest changes in the fuel injection system for operation with diesel fuel.

While all of the above advantages make the rotapower engine attractive, the ultimate advantage of this engine is its ability to generate very low emissions.



Simple - with only two or three moving parts
      - Low part count means less cost
      - Few moving parts means less to wear out

Powerful for their size
      - Efficient packaging

Uses the efficient four-stroke combustion process
      - Solid fuel economy
      - Low emissions

      - Engine can be hard mounted
      - Smooth operation at high RPM

      - Reduces the cost of maintenance


The main historical disadvantage

Poor sealing Mazda did have a sealing problem early in their product lifecycle. This was quickly and easily solved by going to a harder material for the apex seals.

Poor emissions performance The high surface to volume ratio of the combustion chamber can lead to more quenching and higher emissions. The Rotapower's charge cooled configuration increases the rotor face and incoming charge temperature which results in less quenching and better combustion.

Poor fuel economy In oil cooled rotary engines, fuel consumption suffers at low power due to oil sloshing losses. In the Rotapower, charge cooling eliminates this source of lost efficiency.


Freedom Rotapower Engine Performance Advantages

High power to weight ratio
- More than 2 HP per pound of installed weight in high-performance versions.
- Compares with 0.6 HP/lb. to 1 HP/lb for 2-strokes and 0.3 HP/lb to 0.65 HP/lb for 4-stroke pistons.

High power to volume ratio
- (Power Output / Volume) > 100 HP per cubic foot of installed volume.
- Compares with 36 HP/ft³ to 50 HP/ft³ for 2-strokes and 10 HP/ft³ to 20 HP/ft³ for 4-stroke piston engines.

Few moving parts
- Moving Parts - only 2 for single rotor engine.
- Compares to 7 parts for 2-stroke and 25 parts for 4-stroke piston with same instantaneous output torque.

Solid fuel economy
- Specific Fuel Consumption < 0.45 lb/HP-hr ~ (stratified charge). Expect <0.4 lb/HP-hr when both stratified charged and turbo-charged.
- Compares to 0.65 lb/HP-hr for 2-strokes and ~ 0.4 lb/HP-hr for the best 4-stroke piston.

Proven multi-fuel performer
- Demonstrated on gasoline, natural gas, alcohol and propane.
- Spark-ignited diesel, kerosine and jet fuel.

Very low emissions levels
See Emissions Performance.

Enhanced energy at exhaust
- Exhaust temperatures > 1500 °F.
- Acts like a naturally occuring thermal reactor.
- Ideal for turbocharge/co-generation applications.

Low vibration levels
Hard mounted engine can be used as part of the structure.

Modular design
Stacking of rotors easily extends range of available power.


Proprietary Technolgy

Rotapower Engine Technology
(Acquired or Developed)

Patented intake and porting arrangement increases power by 50% versus OMC rotary engine of the same displacement.

Low cost patented approach to insulating the rotor bearing from the rotor.

Proprietary tip seals and rotor housing coating provides projected seal life of over 10,000 hours.

Tuned intake and exhaust system to achieve over 100% volumetric efficiency (using SuperTrapp technology).

Patented composite coating has the following advantages
1, Lowers specific fuel consumption by over 16%.
2, Reduces rotor housing cooling load by 25%.
3, Reduces rotor cooling air requirements by over 40%.
4, Reduces emissions to near zero with charge cooling.
5, Provides solid lubrication at very elevated temperatures (600° F)

State-of-the-art fuel injection system

Operated Freedom Motors developed engines on diesel, alcohol and kerosene as fuels

Patented lubrication system eliminates either mixing oil with fuel (OMC), or injecting oil into incoming air stream (Mazda)

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