Single Stroke Engine Overview

Key Highlights

• Name: Single Stroke Engine, also known as the Innovation (IN) Engine
• Origin: Granada, Spain
• Installed & Tested in: Mazda MX-5
• Specifications:
  • Produces 120 horsepower
  • 500 cc displacement
  • Weighs 35 kg
  • Dimensions: 40 cm
• Unique Claims: Combines advancements from various engine types

How It Works

• Piston Arrangement: 8 pistons in an opposed position
• Key Component: Complex shaped wavy component instead of traditional cylinder head and crankshaft
• Operation:
  • Pistons rest on rollers riding along the wavy surface
  • Combustion force pushes pistons and rotates the wavy component
  • Shared shaft connects two wavy components generating a single torque output at both ends
  • No cylinder head, cams, or valves; no need for cam belt or cam chain
• Intake & Exhaust:
  • Operates like a two-stroke engine
  • Intake and exhaust ports are uncovered by piston movement
  • Fuel injection and spark plug located between pistons

Scavenging Process

• Mechanism: Similar to traditional engines
  • Exhaust Port releases gases creating a vacuum
  • Intake charge rushes into the combustion chamber
  • Compression begins after intake and exhaust ports seal
  • Combustion ignited by spark plug generates pressure driving pistons downward

Features & Advantages

• Direct Injection: Avoids traditional direct injection problems by eliminating intake valves
• Efficiency: Opposed piston design absorbs and extracts more combustion energy
• Variable Compression Ratio:
  • Mechanism to adjust compression using angled grooves
  • Allows combination with turbocharger for high boost at high RPM
• Engine Balance: Perfect primary and secondary balance due to opposed piston arrangement

Challenges & Skepticism

• Torque Output:
  • Likely low RPM torque due to small torque bursts from multiple pistons and their leverage
  • Claims of 150 Nm torque are impressive but RPM range is unclear
• Comparison with Conventional Engines: Lacks significant leverage present in crankshaft engines
• Performance Concerns:
  • Questionable performance without forced induction
  • Absence of full throttle acceleration footage adds to skepticism

Marketing and Claims Examination

• Misleading One-Stroke Claim: The IN Engine operates on a two-stroke cycle with two distinct strokes (combustion/exhaust and intake/compression)
• Combustion Events: True combustion pattern is akin to a conventional four-stroke, four-cylinder engine firing every 180 degrees
• Piston Ring Friction: Equivalent to conventional V8 engines potentially offsetting efficiency gains