"Relative-Motion” Racing Engine Design

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Modern series cap fuel load, fuel mass‑flow, and RPM. The Relative‑Motion Engine (RME) targets more work per unit fuel and usable torque at lower RPM, so teams can meet these caps without giving up lap performance. The trade is a gearing/shift‑strategy update rather than chasing extreme engine speeds.

• Higher indicated work at lower mean piston speed. Internal, every‑cycle charging (via the floating piston) increases indicated work potential without relying on high RPM.
• Pathway to better brake efficiency. By shifting work to lower RPM and reducing friction/pumping, RME aims to lower BSFC at target duty points (to be validated), extracting more shaft power from the same fuel mass‑flow cap.
• Torque where you race. A broader, lower‑speed torque curve supports taller gearing and fewer shifts—useful under flow/energy‑limited rules.

All benefits are established against a matched single‑piston baseline on an instrumented dyno before any track claims.

If the RME delivers ~2× the usable torque at a given operating point (illustrative), the same wheel power can be achieved at roughly half the crank speed, after adjusting final drive. In practice the ratio depends on: gearset choices, track demands, aero drag, and the verified torque curve. The point: speed from torque, not from ever‑higher RPM.

• Conventional cylinder. One cylinder with ≈1,000 cm³ displacement replenishes ~1,000 cm³ of fresh charge each cycle (at NA reference).
• RME concept. With two pistons moving in the same direction, the main crank piston can retain a similar bore (e.g., 100 mm class) while the effective replenishment volume per cycle is smaller (illustratively ~60% of displacement) because the floating piston occupies part of the chamber during filling.
• Implication under fuel‑flow caps. Less replenished fresh charge per cycle → less fuel per cycle at a given λ. If brake efficiency improves, power at the same mandated fuel flow can be maintained.

Note: the exact replenishment fraction is calibration‑dependent (valve timing, piston geometry, speed). We publish dyno maps with measured λ, trapped mass, and BSFC.

The floating piston acts as a timed occupying structure, letting the four processes complete within one cycle across two coupled spaces:

• Power and expansion dominate in the lower (crank) chamber.
• Compression/charging occurs in the upper pocket during the return of the power event.
  This consolidation reduces reliance on high RPM for gas exchange and can lower friction for the same wheel power.

• Gearing. Taller final drive or longer 3rd/4th to exploit low‑RPM torque; recalibrate shift points.
• Cooling & thermal. Lower piston speeds target lower friction heating; validate water/oil circuits for sustained stints.
• Fuel & air. Map for series‑legal fuel mass‑flow; log λ and rail pressure to document compliance.
• Controls. Torque shaping via piston timing/geometry and ECU (spark/SoI/EGR for SI/CI variants).
• NVH. Expect different harmonics due to reduced speed; retune mounts and exhaust.

• Operating at lower RPM for a given wheel power reduces peak inertial loads on rods, pins, and bearings, aiming for improved reliability under endurance cycles.
• Concentrating pressure loads within the floating‑piston structure helps manage block‑borne stress (subject to validation).
• Split‑chamber operation targets lower localized temperatures and controlled burn durations—good for detonation margin.

• Baseline: Single cylinder, 1,000 cm³ displacement, consumes fuel mass m˙f\dot m_fm˙f​ per cycle at λ=target, produces useful work WbW_bWb​.
• RME case: Main piston keeps similar bore; effective replenishment ~600 cm³; fuel per cycle scales accordingly. If dyno shows ≥\ge≥ similar WbW_bWb​ at the same regulated m˙f\dot m_fm˙f​ (due to better efficiency and torque shaping), the crank speed can be reduced with gearing while holding lap performance.
  Actual numbers are set by measured IMEP/BMEP/BSFC and certified fuel‑flow logs.

• Power/torque maps vs RPM and fuel mass‑flow (dyno).
• BSFC at mandated λ and fuel spec.
• Lambda control and instantaneous fuel‑flow trace (FIA‑style logging where applicable).
• Thermal & reliability: oil/water temps, bearing loads, PRR/PCP limits.
• Noise: on‑track dBA and spectral content.

RME reshapes how you meet fuel/flow/RPM caps: more torque, sooner and similar power at lower engine speed with a gearing update. The result is a package aimed at efficiency‑led speed—not headline RPM—while staying within standard physics and series rules.

• Conventional engines approach durability and friction limits as piston speeds rise (around 6,000 rpm in many platforms). Because the Relative-Motion Engine (RME) performs combustion and compression in separate, coupled spaces, it can deliver similar vehicle performance at roughly 3,000 rpm, reducing inertial stress and friction (with appropriate gearing and calibration).
   

Technical

• In many conventional designs, sustained operation near 6,000 rpm pushes rod bearings, wrist pins, and rings toward high inertial load and friction losses. The RME consolidates the four processes within one cycle across two compartments, enabling comparable wheel power at ~half the crank speed (≈3,000 rpm), contingent on gearing. Example: with a 100 mm stroke, mean piston speed drops from 20 m/s at 6,000 rpm to 10 m/s at 3,000 rpm, easing durability and heat-rejection demands.
   

Ultra-brief

• Same speed, lower revs: RME targets ~3,000 rpm for the wheel performance a conventional engine needs ~6,000 rpm to achieve, thanks to split-chamber combustion/compression and improved charge handling.