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added two stroke scenario with vehicle

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max
2026-06-09 21:35:48 +02:00
parent ac2eab6f83
commit 1240ebc33d
8 changed files with 901 additions and 232 deletions
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212
Components/Cylinder.cs
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@@ -1,99 +1,25 @@
using System;
using System.Collections.Generic;
using FluidSim.Interfaces;
using FluidSim.Components; // if needed
namespace FluidSim.Components
{
public class Cylinder : IComponent
public class Cylinder : EngineCylinder
{
public Port IntakePort { get; }
public Port ExhaustPort { get; }
public Crankshaft Crankshaft { get; }
public float IVO, IVC, EVO, EVC; // degrees in a 720° cycle
private readonly Port[] _ports;
IReadOnlyList<Port> IComponent.Ports => _ports;
protected override float CycleLengthRad => 4f * MathF.PI;
protected override float MaxCycleDeg => 720f;
public float Bore { get; }
public float Stroke { get; }
public float ConRodLength { get; }
public float CompressionRatio { get; }
public float IVO, IVC, EVO, EVC; // degrees
public float IntakeValveDiameter = 0.03f;
public float ExhaustValveDiameter = 0.028f;
public float IntakeValveLift = 0.005f;
public float ExhaustValveLift = 0.005f;
public float IntakeValveMaxArea => MathF.PI * IntakeValveDiameter * IntakeValveLift;
public float ExhaustValveMaxArea => MathF.PI * ExhaustValveDiameter * ExhaustValveLift;
public float SparkAdvance = 20f;
public float WiebeA = 5f, WiebeM = 2f, WiebeDuration = 60f, WiebeStart = 5f;
public float StoichiometricAFR = 14.7f;
public float FuelLowerHeatingValue = 44e6f;
public float EnergyVariationFraction = 0.05f;
public float MisfireProbability = 0.0f;
public float CylinderWallArea = 0.02f;
public float HeatTransferCoefficient = 100f;
public float AmbientTemperature = 300f;
public float PhaseOffset; // rad
public float Volume => cylinderVolume;
public float Pressure => (Gamma - 1f) * cylinderEnergy / MathF.Max(cylinderVolume, 1e-12f);
public float Temperature => Pressure / MathF.Max(Density * GasConstant, 1e-12f);
public float Density => Mass / MathF.Max(cylinderVolume, 1e-12f);
public float Mass => _airMass + _exhaustMass;
public float AirFraction => _airMass / MathF.Max(Mass, 1e-12f);
public float PistonFraction => (cylinderVolume - clearanceVolume) / SweptVolume;
private float cylinderVolume, cylinderEnergy;
private float _airMass, _exhaustMass;
private float trappedAirMass, fuelMass, burnFraction;
private bool combustionActive, fuelInjected;
private float _energyFactor = 1f;
private readonly Random _random = new Random();
private const float Gamma = 1.4f;
private const float GasConstant = 287f;
private const float MaxPressurePa = 200e5f;
private const float MaxTemperatureK = 3500f;
public override float IntakeValveArea =>
MathF.PI * IntakeValveDiameter * ValveLift(CrankDeg, IVO, IVC, IntakeValveLift);
public override float ExhaustValveArea =>
MathF.PI * ExhaustValveDiameter * ValveLift(CrankDeg, EVO, EVC, ExhaustValveLift);
public Cylinder(float bore, float stroke, float conRodLength, float compressionRatio,
float ivo, float ivc, float evo, float evc, Crankshaft crankshaft)
: base(bore, stroke, conRodLength, compressionRatio, crankshaft)
{
Bore = bore; Stroke = stroke; ConRodLength = conRodLength;
CompressionRatio = compressionRatio;
IVO = ivo; IVC = ivc; EVO = evo; EVC = evc;
Crankshaft = crankshaft ?? throw new ArgumentNullException(nameof(crankshaft));
cylinderVolume = clearanceVolume;
float initRho = 1.225f;
_airMass = initRho * clearanceVolume;
_exhaustMass = 0f;
cylinderEnergy = 101325f * clearanceVolume / (Gamma - 1f);
IntakePort = new Port { Owner = this };
ExhaustPort = new Port { Owner = this };
_ports = new[] { IntakePort, ExhaustPort };
}
private float SweptVolume => MathF.PI * 0.25f * Bore * Bore * Stroke;
private float clearanceVolume => SweptVolume / (CompressionRatio - 1f);
private float CrankRadius => Stroke * 0.5f;
private float Obliquity => CrankRadius / ConRodLength;
private float CrankDeg =>
((Crankshaft.CrankAngle + PhaseOffset) % (4f * MathF.PI)) * 180f / MathF.PI % 720f;
public float ComputeVolume(float thetaRad)
{
float r = CrankRadius, l = ConRodLength;
float cosTh = MathF.Cos(thetaRad), sinTh = MathF.Sin(thetaRad);
float term = MathF.Sqrt(1f - Obliquity * Obliquity * sinTh * sinTh);
float x = r * (1f - cosTh) + l * (1f - term);
float area = MathF.PI * 0.25f * Bore * Bore;
return clearanceVolume + area * x;
}
private float ValveLift(float thetaDeg, float opens, float closes, float peakLift)
@@ -101,15 +27,10 @@ namespace FluidSim.Components
float deg = thetaDeg % 720f;
if (deg < 0f) deg += 720f;
float duration;
float effectiveOpen = opens;
float effectiveClose = closes;
if (closes < opens)
{
effectiveClose += 720f;
}
duration = effectiveClose - effectiveOpen;
if (closes < opens) effectiveClose += 720f;
float duration = effectiveClose - effectiveOpen;
if (duration <= 0f) return 0f;
float mapped = deg;
@@ -136,43 +57,9 @@ namespace FluidSim.Components
return 0f;
}
public float IntakeValveArea =>
MathF.PI * IntakeValveDiameter * ValveLift(CrankDeg, IVO, IVC, IntakeValveLift);
public float ExhaustValveArea =>
MathF.PI * ExhaustValveDiameter * ValveLift(CrankDeg, EVO, EVC, ExhaustValveLift);
private float Wiebe(float angleSinceSpark)
protected override void HandleCycleEvents(float prevDeg, float currDeg, float dt)
{
if (angleSinceSpark < WiebeStart) return 0f;
float phi = (angleSinceSpark - WiebeStart) / WiebeDuration;
if (phi <= 0f) return 0f;
return 1f - MathF.Exp(-WiebeA * MathF.Pow(phi, WiebeM + 1f));
}
public void PreStep(float dt)
{
// Speed‑dependent spark advance (simple linear)
float rpm = Crankshaft.AngularVelocity * 60f / (2f * MathF.PI);
SparkAdvance = Math.Clamp(10f + rpm * 0.002f, 5f, 40f); // 10° at idle, ~30° at 10k rpm
float prevVolume = cylinderVolume;
float crankAngleRad = Crankshaft.CrankAngle + PhaseOffset;
cylinderVolume = ComputeVolume(crankAngleRad);
float dV = cylinderVolume - prevVolume;
float pRel = Pressure - 101325f;
float sinTh = MathF.Sin(crankAngleRad), cosTh = MathF.Cos(crankAngleRad);
float term = MathF.Sqrt(1f - Obliquity * Obliquity * sinTh * sinTh);
float dxdtheta = CrankRadius * sinTh * (1f + Obliquity * cosTh / term);
float pistonArea = MathF.PI * 0.25f * Bore * Bore;
Crankshaft.AddTorque(pRel * pistonArea * dxdtheta);
cylinderEnergy -= Pressure * dV;
float prevDeg = (Crankshaft.PreviousAngle + PhaseOffset) * 180f / MathF.PI % 720f;
float currDeg = crankAngleRad * 180f / MathF.PI % 720f;
// Intake closing – triggers fuel injection
// Intake closing → fuel injection
if (prevDeg >= IVO && prevDeg < IVC && currDeg >= IVC)
{
trappedAirMass = _airMass;
@@ -180,11 +67,14 @@ namespace FluidSim.Components
fuelInjected = true;
}
// Spark
float sparkAngle = 0f - SparkAdvance;
if (sparkAngle < 0f) sparkAngle += 720f;
bool crossedSpark = (prevDeg < sparkAngle && currDeg >= sparkAngle) ||
(prevDeg > sparkAngle + 360f && currDeg < sparkAngle);
// Spark – occurs at TDC (0°) minus advance, every 720°
float sparkAngle = (0f - SparkAdvance + 720f) % 720f;
bool crossedSpark = false;
if (prevDeg < sparkAngle && currDeg >= sparkAngle)
crossedSpark = true;
else if (prevDeg > sparkAngle && currDeg < sparkAngle)
crossedSpark = true;
if (crossedSpark && !combustionActive && fuelInjected)
{
if (_random.NextDouble() < MisfireProbability)
@@ -199,7 +89,7 @@ namespace FluidSim.Components
}
}
// Combustion
// Combustion progression
if (combustionActive)
{
float angleSinceSpark = currDeg - sparkAngle;
@@ -222,62 +112,6 @@ namespace FluidSim.Components
burnFraction = newFraction;
}
}
// Heat loss
float dQ_loss = HeatTransferCoefficient * CylinderWallArea *
(Temperature - AmbientTemperature) * dt;
cylinderEnergy -= dQ_loss;
// Update port states
float p = Pressure, rho = Density, T = Temperature;
float h = Gamma / (Gamma - 1f) * p / MathF.Max(rho, 1e-12f);
float af = AirFraction;
IntakePort.Pressure = p; IntakePort.Density = rho;
IntakePort.Temperature = T; IntakePort.SpecificEnthalpy = h; IntakePort.AirFraction = af;
ExhaustPort.Pressure = p; ExhaustPort.Density = rho;
ExhaustPort.Temperature = T; ExhaustPort.SpecificEnthalpy = h; ExhaustPort.AirFraction = af;
}
public void UpdateState(float dt)
{
float dmAir = 0f, dmExhaust = 0f, dE = 0f;
foreach (var port in _ports)
{
float mdot = port.MassFlowRate;
float af = mdot >= 0f ? port.AirFraction : AirFraction;
dmAir += mdot * af * dt;
dmExhaust += mdot * (1f - af) * dt;
dE += mdot * port.SpecificEnthalpy * dt;
}
_airMass += dmAir; _exhaustMass += dmExhaust;
cylinderEnergy += dE;
float V = MathF.Max(cylinderVolume, 1e-12f);
float currentP = (Gamma - 1f) * cylinderEnergy / V;
if (currentP > MaxPressurePa) cylinderEnergy = MaxPressurePa * V / (Gamma - 1f);
float currentRho = (_airMass + _exhaustMass) / V;
float currentT = currentP / MathF.Max(currentRho * GasConstant, 1e-12f);
if (currentT > MaxTemperatureK)
{
float pAtTlimit = currentRho * GasConstant * MaxTemperatureK;
cylinderEnergy = pAtTlimit * V / (Gamma - 1f);
}
float totalMass = _airMass + _exhaustMass;
if (totalMass < 1e-9f)
{
_airMass = 1e-9f; _exhaustMass = 0f;
cylinderEnergy = 101325f * V / (Gamma - 1f);
}
else if (cylinderEnergy < 0f)
{
cylinderEnergy = 101325f * V / (Gamma - 1f);
}
if (_airMass < 0f) _airMass = 0f;
if (_exhaustMass < 0f) _exhaustMass = 0f;
}
}
}