How Rotary Engines Work

Overview

• Rotary engines are internal combustion engines.
• They differ from conventional piston engines in their operation.
• Each of the four engine jobs (intake, compression, combustion, exhaust) occurs in separate parts of the housing.
• Developed by Dr. Felix Wankel, hence sometimes called Wankel engines.

Principles of a Rotary Engine

• Utilizes pressure from burning air and fuel.
• Pressure in rotary engines is contained in chambers formed by the housing and rotor face.
• The rotor creates a path similar to a Spirograph, keeping contact with the housing.
• This movement allows gas volumes to expand and contract, facilitating the engine cycle.

Mazda RX-8

• Pioneer in rotary engine cars.
• Features RENESIS, an award-winning rotary engine.
• Produces about 250 horsepower.

Parts of a Rotary Engine

Rotor

• Acts like a piston with three convex faces.
• Has pockets to increase displacement and sealed by metal blades and rings.
• Contains internal gear teeth that interact with housing gears.

Housing

• Oval-shaped, called an epitrochoid.
• Contains different sections for each engine job: intake, compression, combustion, exhaust.
• Direct connection to exhaust and throttle, no valves.

Output Shaft

• Has eccentric lobes the rotors fit over.
• Similar function to a crankshaft, generating torque.

Rotary Engine Assembly

• Assembled in layers, held by long bolts.
• Layers include seals, bearings, and intake ports.
• Rotors have gears interacting with housing gears.

Rotary Engine Power

• Follows four-stroke combustion cycle like piston engines.
• The lobe on the output shaft rotates three times per rotor revolution.
• Rotor's motion changes chamber sizes, enabling the cycle phases:
  • Intake: Air/fuel drawn in as chamber expands.
  • Compression: Mixture compressed as rotor moves.
  • Combustion: Ignited by spark plugs, forcing rotor movement.
  • Exhaust: Gases exit as chamber contracts.

Differences and Challenges

Advantages

• Fewer moving parts than piston engines.
• Smoother operation with continuous directional spinning.
• Slower main moving parts, enhancing reliability.

Challenges

• Meeting emissions regulations is challenging.
• Higher manufacturing costs.
• Greater fuel consumption due to engine design.

Rotary Engine FAQ

• Function: Separates engine cycle into four distinct parts.
• Disadvantages: Difficult emissions compliance and higher fuel consumption.
• Advantages: Reliability, smooth operation, fewer parts.

Additional Information

• For more in-depth knowledge, explore additional resources on rotary engines.