Skip to content

Project-NIC/NIC-BumbleBee

Repository files navigation

English · Čeština · Русский

★ N.I.C. ★

NIC-FPLG

Free-Piston Linear Generator — Open Concept

License: MIT Status: Concept


What is FPLG?

NIC-FPLG is an open concept for a two-stroke two-cylinder linear engine with an integrated tubular linear generator. No crankshaft. No camshaft. No valvetrain. Two pistons share a single rod; a tubular generator sits at the rod's centre. The engine runs permanently at one operating point in mechanical resonance; power output is regulated by the battery, not the engine.

The project grew out of a simple observation: a crankshaft converts linear motion to rotary motion just to convert it back to linear in the generator. Every intermediate conversion has losses and complexity. FPLG cuts the middle out.


Why not a conventional crankshaft engine?

  • Operating point follows a full RPM map — every fuel, every load needs its own calibration
  • Crankshaft, camshaft, valvetrain, timing chain — every moving part is a failure mode
  • Resonance is impossible — frequency is locked to RPM, not to the physical system
  • Thermal expansion mismatch between dissimilar materials requires tight tolerances everywhere

Why not a rotary generator?

  • Linear motion converted to rotary and back — two mechanical conversions, two sets of losses
  • Crankshaft bearings carry the full combustion load at an angle
  • Multi-fuel operation requires a full RPM × load map per fuel

Why a free-piston linear design?

  • One permanent operating point — three numbers per fuel instead of a full map
  • Resonance frequency set by geometry: air spring (under-piston pre-compression ~1:2) plus rod mass form a resonator — tuned by design, not software
  • Matched alloy piston and sleeve — identical thermal expansion, constant clearance at all temperatures
  • Geometry does the work: drop-shaped pockets in the piston face direct flow and spin the charge without a camshaft; valve inertia delays transfer timing so the exhaust leaves first

How it works

One operating point

The engine never changes RPM. The battery absorbs all variable demand. Switching fuels (petrol / LPG / diesel+petrol) means changing three numbers — advance, mixture, oil dose — not remapping an entire table.

Mechanical resonance

Under-piston pre-compression (~1:2) forms an air spring. Air spring plus rod mass form a resonator. The operating frequency is set by the volume below the pistons and the rod mass — tuned by design, not by software. Running in resonance means the air spring returns reversal energy for free; the generator only takes useful work.

Charge transfer

No transfer ports in the cylinder wall. Transfer happens through valves in the piston face — racing motorcycle exhaust valves (~16 mm), running in a cold role (washed by fresh mixture from below). Drop-shaped pockets around each valve direct the charge toward the spark plug and impart rotation to the piston on every firing stroke. Valve inertia creates a natural phase delay — exhaust opens first, transfer follows.

Generator

Tubular flux-switching machine with hybrid excitation (~50 % permanent magnet / ~50 % field winding). Magnets and coils sit in the stator; the rod carries only passive laminated teeth — minimum moving mass, magnets in the cooled zone. Field can be reduced to near-zero for start-up and ramped up gradually to regulate output.


Documentation

Document Description
DESIGN-FPLG.md Full technical concept — 20 chapters
OPEN-QUESTIONS.md What we don't know — simulation and test tasks
SCHEMA-FPLG.svg Schematic cross-section (placeholder)
calc/ (planned) numerical models — resonance, cycle

Status

Concept stage. Core architecture and design philosophy are defined. Simulations, calculations, and a prototype are next.

Contributions welcome — simulation, dynamics, manufacturing, or anyone who finds a hole in the reasoning. A specific objection is worth more than applause.


License

MIT License — Copyright (c) 2026 NIC — Native Intellect Community


Acknowledgements

Brother for advice during the development of this project. For technical review during concept development, to AI assistant Claude (Anthropic).

★ Viva La Resistánce ★