Control emissions at the cylinder level, with Zero CO, Zero HC and near zero NO

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Third-party testing report

A third-party CONVERGE CFD study (ARAI, India) started a simulation testing 2023 and reported a summary of ~40% torque/indicated-work improvement for an RME geometry vs. a conventional cylinder, driven by increased density/MEP from the floating-piston space-void effect

Study frozen halfway pending answer to design questions of practical lubrication solution and breathing capacity. Challanges were answered by a newly issued patent US 12372016

Oil lubrication solution solved an immediate and historical challenges of using skirts in a combustion engines, which proved preferred to manufacturing for all the other reason other than the oil challange issue.

Air inspiration capacity in the attached summary was lower than the base conventional engine, solved and patented promissing a much better resuts.

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The oil lubrication Challenge

1️ Why the 1950s Sleeve Designs Consumed So Much Oil

The Historical Problem

In older moving-sleeve engines:

The sleeve reciprocated at high speed against the cylinder wall, often with long travel.
Oil particles between the sleeve and the wall were repeatedly trapped and compressed at high frequency.
This constant mechanical “pumping” action broke down the oil film and subjected the oil particle to a continuous pressure more than 4 bars as a result of the high speed reciprocation of oil particle trapped in reciprocation.
The result: high oil consumption and reduced lubrication life.

2️ Relative Motion Engine’s Mechanical Layout

The primary historical failure mode for sleeve designs wasn’t only oil getting into the combustion chamber or being pumped out to drains — it was the mechanical compression / shearing of oil particles by the high-speed reciprocation of the sleeve.
Those repeated compression events easily produced local pressures > ~4 bar on oil droplets/films. That level of cyclic mechanical stress breaks down the lubricant film and forces oil out of the effective lubrication zone (and into places it shouldn’t be), which is what drove extremely high consumption in the old engines.
The Relative Motion approach avoids producing those damaging pressure spikes by three interlocking measures you confirmed with the team:

Integrated floating piston+sleeve assembly — removes relative sliding between sleeve and piston, drastically reducing shear cycles on oil.
Reduced sleeve stroke (~60% of the old designs) — less travel → smaller volumetric/pressure changes in the film per cycle.
Sleeve offset / clearance from cylinder wall — the sleeve does not trap or squeeze oil against the wall, so the transient local pressures that used to exceed ~4 bar are not generated.

As you also noted, strategies like controlled metering and oil circuits are modern best practices but are general improvements rather than the unique solution here.

Self‑Charging Cylinder Design

Custom Design and Prototyping

Self‑Charging Cylinder (Relative Motion Engine)

Plain summary
A two‑piston, pressure‑coupled cylinder that “self‑charges” the chamber each cycle. The floating piston shares the combustion space but is not crank‑driven; the same in‑cylinder pressure accelerates both pistons in the same direction, raising indicated work without crank back‑drive. Shaped timing/area of the floating piston produces unsteady in‑cylinder compression and scavenging—an internal, every‑cycle charging effect.

Why it matters

Conventional engines sacrifice efficiency to friction at high mean piston speed and to pumping/heat losses during gas exchange. By increasing indicated work at lower RPM while improving charge preparation, the Self‑Charging Cylinder targets lower fuel consumption and emissions—first in stationary power and heavy‑duty applications, then in broader ICE/hybrid use cases.

How it works (high level)

Decoupled floating piston. Shares the chamber but is not mechanically linked to the crankshaft; no shaft back‑drive.
Pressure‑driven motion. During combustion, the pressure field does work on both pistons, with the crank receiving torque only from the main piston.
Unsteady charging. The floating piston’s geometry and timing create cycle‑by‑cycle compression and enhanced airflow/scavenging inside the cylinder—an internal supercharging effect without external compressors.

Floating‑piston phasing & coupling

Phased coupling (overview). We start decoupled so in‑cylinder pressure drives the floating piston to co‑accelerate with the main piston in the same direction. After geometry/timing are validated, we link the floating piston to the crank via two rods to stabilize motion, capture a small net positive torque contribution (~3% historically observed from skirt‑effect data), and use the return portion of the power event to compress the air above the floating piston—replacing the separate compression stroke in a conventional cylinder.

Initial decoupled mode (technical). Combustion pressure first accelerates the floating piston toward the crank, aligning its motion with the main piston. As the pressure field evolves, the floating piston’s instantaneous acceleration can change sign, but its net displacement over the cycle remains co‑directed with the main piston. Any small pressure‑driven “shake” informs sizing/timing during this phase.

Stabilized linked mode (technical). Once validated, two connecting rods couple the floating piston to the crank. The crank then damps residual oscillation and harvests a small average positive driving force. During the return, the linkage provides the additional function of compressing the air pocket above the floating piston. This is not an added loss vs a conventional cylinder; it relocates compression work (done in a separate stroke in conventional cycles) into the return of the same cycle, while the Relative Motion Cylinder may employ a larger bore and shorter stroke.

What we learned (five‑year development)

Static Pascal assumptions fail in open, unsteady flow. Early concepts that treated the chamber like a closed hydraulic system (or added springs) under‑performed.
Co‑acceleration is key. Removing springs and shaping the floating piston to co‑accelerate with the main piston improved unsteady compressible‑flow coupling and charge handling.
Use standard engine metrics. Report IMEP/indicated work separately from PCP (peak cylinder pressure) and from brake metrics (BMEP/BSFC). Avoid nonstandard terms.

Simulation evidence (internal)

Indicated cycle work: ~30–40% increase vs a matched single‑piston baseline (ANSYS/CONVERGE studies, 2017–present).
Pressure capability: simulated PCP up to ~180 bar with acceptable pressure‑rise rates in tuned cases.
Charge enhancement: at selected operating points, simulations show up to ~2.6× airflow vs conventional naturally aspirated (NA) operation—comparable to strong turbocharging without external hardware.
Friction potential: operation at lower mean piston speed for a given brake load targets FMEP reductions (quantified by motored tests in hardware).

All figures above are simulation‑only until confirmed on an instrumented single‑cylinder test rig. Full model details (mesh, chemistry, turbulence, wall heat transfer, boundary/ICs, sensitivity) will accompany publication.

Clarifying language

“Space void.” In standard terms: transient gas displacement by the floating piston that raises local pressure and changes in‑cylinder flow. We describe this as a pressure‑wave/gas‑spring effect, not a literal void.
“Trapped mass phenomenon.” Certain CONVERGE post‑processing runs reported apparent trapped mass above the nominal input. We treat this as a modeling/recirculation and discretization artifact until verified experimentally. We continue to collaborate on diagnostics and mesh/solver sensitivity.

Engineering benefits (target outcomes)

Higher indicated work at lower RPM → potential BSFC gains after friction/pumping losses are measured.
Internal, every‑cycle charging → improved mixture preparation and scavenging without external compressors.
Friction reduction via lower mean piston speed for a given brake load (to be quantified as FMEP).
Diesel‑class power density at lower rated speed. Completing effective gas‑exchange every cycle can raise work per rev; goal: match gasoline‑class power density with diesel‑class speeds (hardware validation pending).
Materials & NVH potential. Concentrating peak combustion loads within the floating‑piston structure may enable aluminum blocks in diesel‑class applications and reduce block‑borne noise/vibration (to be tested).
Emissions levers in‑cylinder. Mixture/temperature control and pressure‑wave charging aim to reduce aftertreatment load; we will demonstrate NOx/CO/HC/PN vs baseline on a certified bench.
EGR conflict mitigation. Internal re‑breathing via exhaust valve sizing/position can decouple airflow enhancement from NOx control, targeting 30–40% internal exhaust fraction without intake‑path recirculation.
Oil consumption. A patented sleeve/sealing approach addresses historical sleeve‑engine oil usage (details under NDA).

What’s validated vs. what’s next

Validated in simulation

+30–40% indicated work (IMEP) at selected points.
PCP ~180 bar in tuned cases with acceptable PRR.
Up to ~2.6× airflow vs NA baseline at matched conditions.

To be validated in hardware

BSFC improvement at equal brake torque (target ≥10%).
FMEP reduction at matched load/speed.
Emissions: NOx/CO/HC/PN equal‑or‑better than baseline.
Durability, blow‑by, and NVH within design limits.

Comparison: Self‑Charging Cylinder vs advanced two‑stroke poppet‑valve concepts

Vibration management: pressure‑coupled floating piston reduces lateral forces and block‑borne excitation.
Friction: fewer high‑speed valvetrain events at a given output → lower FMEP potential.
Parts count: simplified external air‑handling; potential elimination of side camshafts in some architectures.
Gas exchange: no partial loss of compressed intake through early exhaust opening; longer effective scavenging window per cycle.
Scalability: internal charging can stand alone or stack with turbocharging if higher overall pressure ratio is required.

Implementation options

Naturally aspirated internal‑charging for simplicity and cost.
Hybrid with turbocharging where additional pressure ratio is needed.
Control strategy uses piston geometry/timing and conventional ECU maps for SoI/spark/EGR; no exotic hardware required.

Roadmap & proof

Phase 1: single‑cylinder rig with fast in‑cylinder pressure, torque, emissions bench; IMEP/BMEP/BSFC mapping and motored FMEP.
Phase 2: 25–100 kW pilot genset prototype with partner; third‑party validation.
Phase 3: certification pathway and OEM licensing/retrofit packages.

Can the RME run despite a high compression power penalty ?

Latest solved challange

can the engine run if we triple the floating piton surface, for a Diezel engine using 17:1 ratio.?

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Disclosed here is a comparison study with a conventional Naturally aspirated engine (NA) and with a conventional turbo charged.

Results were positive, as the compression power penalty, using triple the bore surface, was exatly similar to that of an equivalant turbcharged cyinder.

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Design models updates

updated design

A second shelfed design

When the occupying structure is mechanically connected to a crankshaft, the overall engine design will be similar in its industrial feasibility and parts requirements to opposed piston arrangements, however, the physics principles involved are completely different.

An opposed-piston engine physically represents motion as a function of position.

Relative Motion cylinder, having two pistons fired at the same direction, represents in physical terms, motion as a function of time, where the second piston creates a field of pressure that changes how the power output is calculated.

By using a skirt from the past century practice, we tried to solve the combustion and ports seeling challanges.

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Good results were accomplished by this design

superior sound and vibration insulation, known of using sleeves.

Failures Realized

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Inferior air flow management

inferior lubrication results

A First ShelfedDesign

Spring-support model

The idea of this assembly was to replace tradetional turbo & Super charge methods, by a control cylinder dedicated only for suction and compression to lower the cooling needs.

Failures Realized

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inferior in friction losses

inferior oil management

inferior air management

limited to a fixed speed applications like a generator

The Trap Mass reading by Coverge

Dynamics of Trap Mass and Density Increase

Dynamics of “Trapped Mass” and Effective Density (CONVERGE)

Plain summary
In our CONVERGE CFD studies of the Relative Motion Engine (RME), the solver sometimes reports trapped mass values that exceed the nominal air‑fuel mass at top‑dead‑center (TDC). This does not mean mass is created. It reflects a higher effective gas density inside the chamber caused by the floating piston reducing the available volume and by transient flow recirculation. Third‑party simulations (ARAI) reported ~40% higher indicated torque under matched conditions before any friction assessment. These results are simulation‑only and require hardware validation.

What “trapped mass” means here

Trapped mass (CFD post‑processing). A reporting quantity based on the mass of gas resident in the cylinder/control volume at a given crank angle. In unsteady conditions with internal volume modulation and back‑and‑forth flow, this number can appear larger than the nominal intake mass.
Effective density increase. The floating piston occupies part of the chamber, reducing instantaneous gas volume. For a given energy release, smaller volume → higher pressure and density. The solver reflects this as a higher in‑cylinder mass equivalent, not as real mass creation.
Not over‑unity. The effect is a pressure/density change from geometry and timing, consistent with mass and energy conservation.

Mechanism (RME geometry)

Two pistons, one pressure field. The floating piston shares the chamber but is not initially crank‑driven; during combustion, the same pressure acts on both pistons.
Volume occupation. The floating piston’s body reduces the gas space dynamically, acting like an internal constrainer/gas spring that raises local pressure and density for part of the cycle.
Unsteady compression & scavenging. The resulting pressure waves and recirculation alter the charge motion and can increase trapped mass readings and indicated work in simulation.

What the simulations reported

Indicated performance: ARAI’s CONVERGE runs (government‑affiliated third party) summarized ~+40% indicated torque vs a same‑size single‑piston case (prior to friction accounting).
Pressure levels: Cases with tuned timing/geometry produced higher peak cylinder pressure (PCP), on the order of ~180 bar in simulation, compared with ~90 bar for a comparable conventional case. (We report PCP separately from IMEP/BMEP to avoid confusion.)
Airflow/charging: At selected operating points, effective air utilization increased (reflected in trapped‑mass reporting and flow fields), consistent with stronger in‑cylinder compression effects.

All figures are CFD‑derived and subject to change after single‑cylinder hardware testing with fast in‑cylinder pressure and a full uncertainty budget.

Independence from decompression volumes & cam systems

The density increase arises inside the combustion chamber during the expansion/power event and is not caused by any auxiliary decompression pocket.
The phenomenon is not camshaft‑dependent: the floating piston’s motion is primarily pressure‑driven and later stabilized by crank linkage (dual rods) in the production intent design, reducing extra valvetrain work.

How CONVERGE can produce a higher trapped‑mass value

Conservation with moving boundaries. CONVERGE enforces mass/momentum/energy conservation with moving meshes and adaptive refinement. When internal geometry modulates volume and promotes recirculation/backflow through ports and crevices, the in‑cylinder control volume can momentarily retain more mass than the nominal intake charge—reported as higher trapped mass.
Interpretation. Treat this as a proxy for higher instantaneous density and residence due to geometry/flow timing—not as added substance.
Modeling note. Apparent mass elevation can be sensitive to mesh resolution, valve leakage models, and control‑volume definitions. We run mesh/physics sensitivity studies and correlate to test.

Physics translation (standard terms)

Compressible flow. Smaller instantaneous volume at similar heat release → higher p and ρ; work follows from the cycle integral Wi=∮p dVW_i = \oint p\,dVWi=∮pdV.
Momentum balance. Pressure‑field impulses transfer to piston force via Navier–Stokes; cycle‑integrated, this maps to IMEP and torque.
Thermal/chemical coupling. Higher density modifies flame speed and heat‑release phasing; benefits must be balanced against knock/NOx/temperature limits.

(We no longer present non‑standard energy formulas here; internal time‑based heuristics are moved to physics pages and retained only for design tuning and are not used for external claims.)

Design implications

Pressure shaping without external turbo. The floating piston provides an internal, every‑cycle charging effect, which can coexist with or reduce reliance on turbocharging.
Friction & parts. Operating at lower mean piston speed for a given brake load and simplifying external air‑handling can reduce FMEP and parts count.
Control. After sizing is validated in the decoupled phase, the floating piston is linked via two rods to stabilize motion and capture a small net positive torque contribution. On the return portion, the linkage performs compression of the pocket above the floating piston—replacing a separate compression stroke in conventional cycles.

What’s validated vs. next steps

Simulation‑supported observations

Apparent trapped‑mass elevation corresponds to effective density increase due to dynamic volume occupation/recirculation.
IMEP/indicated torque gains and elevated PCP in tuned cases.

To be proven in hardware

BSFC improvement at equal brake torque (target ≥10%).
FMEP reduction vs mean piston speed.
Emissions (NOx/CO/HC/PN) equal‑or‑better at matched conditions.
Robustness: blow‑by, oil control, and NVH.

Simplicity & scalability

Fewer external systems. Internal charging can reduce turbo/cooling dependencies at moderate boost levels; turbo can be added if higher overall pressure ratio is needed.
Architecture fit. Best suited for >1.5 L displacement classes where the dual‑rod linkage integrates cleanly; smaller engines may favor other architectures.
Diesel potential. By confining peak loads within the floating‑piston structure, aluminum blocks for diesel‑class duty may be feasible (subject to thermal/mechanical validation).

Notes & attribution

Third‑party CFD work referenced: ARAI summary indicating ~40% indicated torque gain prior to friction assessment (simulation; details under NDA).
All claims above are subject to experimental confirmation on an instrumented single‑cylinder rig with full data disclosure (p–θ, RoHR, PRR, uncertainty).