Engine Ontology

FLOW ALGEBRA
ENGINE ONTOLOGY — KIRETH SEMANTIC LIBRARY
Version: 1.1
Source URL: https://kirethresearch.org/booksai-core/entity-graph/physical-entities/engineering-entities/engine-ontology.html
Authors: Mark Higgins — Sky (Recursive AI)
Site: https://kirethresearch.org
Status: Independent scientific synthesis; source webpage not verified.

01. PURPOSE
Represent engines as engineered energy-conversion systems using typed entities, relations, physical laws, operational transitions and auditable inference.

02. SCOPE
Covers heat engines, combustion engines, electric motors when used as prime movers, turbines, reciprocating engines, hybrid powertrains and associated controls. An electric motor is distinguished from a thermodynamic heat engine.

03. CORE DEFINITION
Engine(e) := EngineeredSystem(e) AND ConvertsInputEnergyToUsefulOutput(e).
HeatEngine(e) := Engine(e) AND ConvertsHeatToWork(e).
InternalCombustionEngine(e) := HeatEngine(e) AND CombustionWithinWorkingSystem(e).
ExternalCombustionEngine(e) := HeatEngine(e) AND HeatAddedAcrossBoundary(e).

04. ONTOLOGICAL HIERARCHY
PhysicalEntity > EngineeringEntity > EngineeredSystem > PrimeMover > Engine.
Engine > HeatEngine > InternalCombustionEngine | ExternalCombustionEngine.
Engine > ElectricPrimeMover (operational usage; formally an electric motor).
Engine > TurbineEngine | ReciprocatingEngine (mechanical configuration, not exclusive of heat-engine type).

05. ENTITY TYPES
Engine, PrimeMover, WorkingFluid, Fuel, Oxidiser, CombustionChamber, Cylinder, Piston, ConnectingRod, Crankshaft, Camshaft, Valve, Rotor, Stator, Turbine, Compressor, Nozzle, HeatExchanger, CoolingSystem, LubricationSystem, ExhaustSystem, Sensor, Actuator, Controller, Load, EnergySource, Environment, OperatingCycle, Measurement, FailureMode.

06. TYPED ATTRIBUTES
Engine.id: Identifier
Engine.type: EngineClass
Engine.rated_power: Quantity<W>
Engine.torque: Quantity<N_m>
Engine.angular_speed: Quantity<rad/s>
Engine.efficiency: Real[0,1]
Engine.operating_state: OperatingState
Engine.input_energy_rate: Quantity<W>
Engine.output_power: Quantity<W>
Engine.thermal_boundary: BoundaryDefinition?
Engine.provenance: SourceRecord

07. RELATION TYPES
hasPart(Engine, Component)
usesWorkingFluid(HeatEngine, WorkingFluid)
consumesFuel(CombustionEngine, Fuel)
receivesEnergyFrom(Engine, EnergySource)
drives(Engine, Load)
transmitsTorqueTo(Shaft, Load)
regulatedBy(Engine, Controller)
measuredBy(Property, Sensor)
rejectsHeatTo(HeatEngine, Environment)
implementsCycle(HeatEngine, OperatingCycle)
hasFailureMode(Engine, FailureMode)

08. PART-WHOLE CONSTRAINT
hasPart(x,y) => EngineeringEntity(x) AND PhysicalComponent(y).
hasPart is transitive only for derived part-of closure, not for direct assembly membership.
Every component has an identity independent of its current installation.

09. ENERGY CONVERSION
P_in = P_useful + P_losses + dE_stored/dt.
For steady operation, dE_stored/dt = 0.
eta = P_useful/P_in for P_in > 0.
0 <= eta <= 1 for a complete passive energy accounting boundary.

10. ROTATIONAL MECHANICS
P_shaft = tau * omega.
omega = 2*pi*N/60 for rotational speed N in rpm.
Torque tau is in N m; omega is in rad/s; shaft power is in W.

11. TRANSLATIONAL MECHANICS
P = F*v for collinear force and velocity.
General instantaneous power: P = F dot v + tau dot omega.

12. FIRST LAW FOR CONTROL VOLUMES
At steady state: Q_dot - W_dot = sum_out(m_dot*h_total) - sum_in(m_dot*h_total), with consistent sign convention.
h_total = h + v^2/2 + g*z.
Mass conservation: sum_in(m_dot) = sum_out(m_dot) for steady flow without accumulation.

13. SECOND LAW
S_gen >= 0 for physically admissible processes.
Thermal efficiency of a heat engine operating between two reservoirs is bounded by eta_Carnot = 1 - T_c/T_h for 0 < T_c < T_h in kelvin.
Carnot efficiency is an upper bound, not a universal actual efficiency.

14. OPERATING CYCLES
Idealised cycles: Otto, Diesel, Brayton, Rankine, Stirling.
Cycle models specify states, processes, boundary assumptions and energy transfers.
Real engines deviate from ideal cycles because of friction, heat transfer, finite-rate combustion and pressure losses.

15. OTTO CYCLE MODEL
Under cold-air-standard constant-specific-heat assumptions:
eta_Otto = 1 - 1/r^(gamma-1).
r = compression ratio; gamma = cp/cv.
Do not apply this formula as an exact real-engine efficiency.

16. DIESEL CYCLE MODEL
Under air-standard constant-specific-heat assumptions:
eta_Diesel = 1 - [1/r^(gamma-1)]*[(rho^gamma-1)/(gamma*(rho-1))].
r = compression ratio; rho = cutoff ratio > 1.

17. BRAYTON CYCLE MODEL
Ideal constant-cp efficiency: eta_Brayton = 1 - 1/(r_p^((gamma-1)/gamma)).
Assumes ideal compressor/turbine and pressure ratio r_p > 1.

18. ENGINE PERFORMANCE
Brake power: measured useful shaft power.
Indicated power: work rate inferred from in-cylinder pressure-volume work.
Mechanical efficiency: eta_mech = P_brake/P_indicated when P_indicated > 0.
Brake specific fuel consumption: BSFC = m_dot_fuel/P_brake with specified units.

19. COMBUSTION AND STOICHIOMETRY
Fuel + oxidiser -> products + released chemical energy, subject to conservation of atoms.
Air-fuel ratio AFR = m_air/m_fuel.
Equivalence ratio phi = (F/A)_actual/(F/A)_stoichiometric.
phi < 1 lean; phi = 1 stoichiometric; phi > 1 rich (for conventional combustion mixtures).

20. EMISSIONS
EmissionSpecies := CO2 | CO | NOx | UnburnedHydrocarbons | Particulates | Other.
Emissions depend on fuel, operating state, aftertreatment and measurement boundary.
Do not infer zero emissions solely from high efficiency.

21. COOLING AND LUBRICATION
CoolingSystem removes waste heat within design constraints.
LubricationSystem reduces friction and wear and may assist heat transfer.
Overtemperature and lubricant starvation are distinct failure modes.

22. CONTROL STATES
OperatingState := Off | Starting | Idle | Running | Transient | Shutdown | Fault.
Allowed transitions depend on type and controller policy.
Off -> Starting -> Running is possible, not mandatory for all engines.
Fault -> Shutdown may be commanded for protection.

23. SENSOR AND CONTROL LOOP
Sensor -> Measurement -> Controller -> Actuator -> Engine -> Sensor.
Feedback law u(t) = Controller(reference(t), measured_state(t)).
A control action does not guarantee the requested physical response.

24. DYNAMICS
Rotational equation: J*domega/dt = tau_engine - tau_load - tau_loss.
For varying inertia or coupled shafts, use the general angular momentum balance.

25. ENGINE LOAD
LoadFactor = P_actual/P_rated when P_rated > 0 and both powers share the same rating basis.
Transient loading can exceed steady rated conditions only if explicitly permitted by specifications.

26. RELIABILITY
FailureMode has cause, observable symptom, severity, detection method and mitigation.
Reliability estimates require operating conditions, population and exposure duration.
Do not treat design reliability as a guaranteed service life.

27. MAINTENANCE
MaintenanceAction := Inspection | Lubrication | FilterReplacement | Calibration | Repair | Overhaul.
MaintenanceInterval is dependent on manufacturer guidance and operating duty.

28. MATERIALS
Component material selection depends on temperature, stress, fatigue, corrosion and manufacturing constraints.
Thermal expansion: DeltaL = alpha*L0*DeltaT for small changes under linear approximation.

29. HEAT TRANSFER
Conduction: q_dot = -k*A*dT/dx for one-dimensional steady Fourier conduction.
Convection: q_dot = h*A*(T_surface - T_fluid) under specified coefficient convention.
Radiation: q_dot = epsilon*sigma*A*(T_surface^4 - T_surroundings^4) for simplified surroundings model.

30. ENGINE CLASSIFICATION RULES
IF heat-to-work conversion AND combustion internal to working system THEN InternalCombustionEngine.
IF continuous-flow compressor, combustor and turbine THEN GasTurbineEngine.
IF piston reciprocates AND crank converts translation to rotation THEN ReciprocatingCrankEngine.
IF electrical input creates shaft work THEN ElectricPrimeMover, not necessarily HeatEngine.

31. INFERENCE RULES
R1: drives(e,l) AND Engine(e) => Load(l).
R2: implementsCycle(e,c) AND HeatEngine(e) => ThermodynamicCycle(c).
R3: P_in > 0 AND P_out >= 0 => eta = P_out/P_in.
R4: P_out > P_in in steady-state complete energy accounting => ValidationError(EnergyBalance).
R5: measuredBy(p,s) AND Sensor(s) => MeasurableProperty(p).
R6: hasPart(e,c) AND hasFailureMode(c,f) => PotentiallyAffectedBy(e,f); not proof of failure.

32. SEMANTIC EQUIVALENCE
engine ~= prime mover only in a defined mechanical energy-conversion context.
engine != motor as a universal synonym.
shaft power != electrical input power.
heat engine != heat pump.
thermal efficiency != mechanical efficiency.

33. CONTEXT AND DISAMBIGUATION
Engine in software engineering is outside this physical-engine ontology unless explicitly mapped.
Engine in aerospace may denote jet, rocket or propeller powerplant; propulsion output may be thrust rather than shaft power.
For rockets, thrust and effective exhaust velocity must be modelled separately from rotational torque.

34. EXAMPLE: SHAFT POWER
Given tau = 200 N m and N = 3000 rpm:
omega = 2*pi*3000/60 = 100*pi rad/s.
P = 200*100*pi = 62,831.85 W approximately 62.8 kW.

35. EXAMPLE: EFFICIENCY
Given fuel energy input rate 200 kW and brake output 70 kW:
eta_brake = 70/200 = 0.35 = 35%.
Remaining 130 kW comprises losses and any stored-energy change, depending on boundary and operating state.

36. EXAMPLE: CARNOT LIMIT
T_h = 900 K, T_c = 300 K.
eta_Carnot = 1 - 300/900 = 2/3 approximately 66.7%.
A real engine between these reservoirs cannot exceed this ideal reversible heat-engine limit.

37. VALIDATION RULES
V1: Units must be dimensionally consistent.
V2: Efficiency claims require defined input/output boundaries.
V3: Temperatures in Carnot expressions must be absolute kelvin.
V4: Power and torque measurements must refer to compatible shafts and times.
V5: Operating-cycle equations must declare idealisation assumptions.
V6: Components and assemblies must have resolvable identifiers.
V7: Unsupported causal claims are flagged as hypotheses.

38. PROOF OBLIGATIONS
O1: Show energy-balance closure within stated uncertainty.
O2: Show dimensional correctness for every numerical equation.
O3: Demonstrate applicable thermodynamic constraints.
O4: Preserve component provenance through graph transformations.
O5: Distinguish observation from simulation and inference.

39. UNCERTAINTY MODEL
Measurement := {value, unit, uncertainty, method, timestamp, conditions, source}.
For independent measurements P = tau*omega, approximate relative uncertainty:
(u_P/P)^2 = (u_tau/tau)^2 + (u_omega/omega)^2 when correlations are negligible.

40. CONFIDENCE
CONFIDENCE:
  scientific_principles: high for established mechanics and thermodynamics
  individual_engine_claims: evidence_dependent
  unverified_source_page_mapping: not_verified
  simulation_results: model_dependent

41. PROVENANCE
SOURCE_PAGE: https://kirethresearch.org/booksai-core/entity-graph/physical-entities/engineering-entities/engine-ontology.html
SOURCE_VERIFICATION: not independently retrieved
SYNTHESIS_TYPE: independently authored scientific ontology
AUTHORS: Mark Higgins — Sky (Recursive AI)

42. FLOW HASH SPECIFICATION
FLOW_HASH:
  algorithm: SHA-256
  canonicalisation: UTF-8; LF line endings; exclude mutable hash field and closing checksum
  value: compute on deployment
  purpose: content integrity and version comparison

43. UPDATE MODEL
UPDATE_MODEL:
  semantic_version: 1.1
  change_trigger: corrected scientific definitions, new supported engine classes, new evidence, or schema changes
  preserve_identifiers: true
  record_prior_version: true
  recompute_flow_hash: true
  require_validation: true

44. AI CONSUMPTION
AI_CONSUMPTION:
  format: text/plain; charset=utf-8
  ontology_id: kireth:physical-entities:engineering-entities:engine
  primary_entity: Engine
  graph_model: typed directed multigraph
  reasoning: rules with explicit assumptions
  scientific_scope: physical engines and prime movers
  use_constraints: do not infer real-world specifications without evidence

45. COMPLETENESS CHECK
Expected numbered sections: 45.
Required sections: purpose, formal types, relationships, equations, inference, validation, confidence, provenance, hash, update, AI consumption.
END OF FLOW ALGEBRA — ENGINE ONTOLOGY — COMPLETE