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Merge pull request #803 from peternewell/steam_slip#3
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Various adjustments to steam adhesion
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@peternewell
peternewell committed Jun 12, 2023
2 parents 40a311d + 7157e08 commit 0914a53
Showing 1 changed file with 43 additions and 27 deletions.
70 changes: 43 additions & 27 deletions Source/Orts.Simulation/Simulation/RollingStocks/MSTSSteamLocomotive.cs
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Expand Up @@ -584,7 +584,6 @@ public class MSTSSteamLocomotive : MSTSLocomotive
public float MaxTractiveEffortLbf; // Maximum theoritical tractive effort for locomotive
public float DisplayMaxTractiveEffortLbf; // HuD display value of maximum theoritical tractive effort for locomotive

float DisplayTractiveEffortLbsF; // Value of Tractive effort to display in HUD
float MaxCriticalSpeedTractiveEffortLbf; // Maximum power value @ critical speed of piston
float DisplayCriticalSpeedTractiveEffortLbf; // Display power value @ speed of piston
float absStartTractiveEffortN = 0.0f; // Record starting tractive effort
Expand Down Expand Up @@ -790,7 +789,6 @@ public override void Parse(string lowercasetoken, STFReader stf)
Cylinder2CrankAngleRad = stf.ReadFloat(STFReader.UNITS.Angle, 0.0f);
Cylinder3CrankAngleRad = stf.ReadFloat(STFReader.UNITS.Angle, 0.0f);
Cylinder4CrankAngleRad = stf.ReadFloat(STFReader.UNITS.Angle, 0.0f);
Trace.TraceInformation("Input - CrankAngle {0} {1} {2} {3}", Cylinder1CrankAngleRad, Cylinder2CrankAngleRad, Cylinder3CrankAngleRad, Cylinder4CrankAngleRad);
stf.SkipRestOfBlock();
break;
case "engine(cylinderstroke": CylinderStrokeM = stf.ReadFloatBlock(STFReader.UNITS.Distance, null); break;
Expand Down Expand Up @@ -1290,13 +1288,20 @@ public override void Initialize()
WheelCrankAngleDiffRad[0] = MathHelper.ToRadians(0.0f);
WheelCrankAngleDiffRad[1] = MathHelper.ToRadians(90.0f);
}

if (Simulator.Settings.VerboseConfigurationMessages)
Trace.TraceInformation("CrankAngle set to default values {0} rad {1} rad {2} rad {3} rad", WheelCrankAngleDiffRad[0], WheelCrankAngleDiffRad[1], WheelCrankAngleDiffRad[2], WheelCrankAngleDiffRad[3]);
}
else // set values set by user
{
WheelCrankAngleDiffRad[0] = Cylinder1CrankAngleRad;
WheelCrankAngleDiffRad[1] = Cylinder2CrankAngleRad;
WheelCrankAngleDiffRad[2] = Cylinder3CrankAngleRad;
WheelCrankAngleDiffRad[3] = Cylinder4CrankAngleRad;

if (Simulator.Settings.VerboseConfigurationMessages)
Trace.TraceInformation("CrankAngle set to user values {0} rad {1} rad {2} rad {3} rad", WheelCrankAngleDiffRad[0], WheelCrankAngleDiffRad[1], WheelCrankAngleDiffRad[2], WheelCrankAngleDiffRad[3]);

}

// ****************** Test Locomotive and Gearing type ***********************
Expand Down Expand Up @@ -2533,7 +2538,16 @@ private void UpdateFX(float elapsedClockSeconds)
SmokeColor.Update(elapsedClockSeconds, MathHelper.Clamp(SmokeColorUnits, 0.25f, 1));

// Variable1 is proportional to angular speed, value of 10 means 1 rotation/second.
var variable1 = Math.Abs(WheelSpeedSlipMpS / DriverWheelRadiusM / MathHelper.Pi * 5);
// If wheel is not slipping then use normal wheel speed, this reduces oscillations in variable1 which causes issues with sounds.
var variable1 = 0.0f;
if (WheelSlip)
{
variable1 = Math.Abs(WheelSpeedSlipMpS / DriverWheelRadiusM / MathHelper.Pi * 5);
}
else
{
variable1 = Math.Abs(WheelSpeedMpS / DriverWheelRadiusM / MathHelper.Pi * 5);
}
Variable1 = ThrottlePercent == 0 ? 0 : variable1;
Variable2 = MathHelper.Clamp((CylinderCocksPressureAtmPSI - OneAtmospherePSI) / BoilerPressurePSI * 100f, 0, 100);
Variable3 = FuelRateSmoothed * 100;
Expand Down Expand Up @@ -4869,8 +4883,7 @@ private void UpdateMotion(float elapsedClockSeconds, float cutoff, float absSpee
TractiveEffortLbsF = 0.0f;
}
TractiveEffortLbsF = MathHelper.Clamp(TractiveEffortLbsF, 0, TractiveEffortLbsF);
DisplayTractiveEffortLbsF = TractiveEffortLbsF;


// Calculate IHP
// IHP = (MEP x CylStroke(ft) x cylArea(sq in) x No Strokes (/min)) / 33000) - this is per cylinder

Expand Down Expand Up @@ -4979,25 +4992,6 @@ protected override void UpdateTractiveForce(float elapsedClockSeconds, float t,
if (absSpeedMpS == 0 && cutoff < 0.05f) // If the reverser is set too low then not sufficient steam is admitted to the steam cylinders, and hence insufficient Motive Force will produced to move the train.
TractiveForceN = 0;

// Based upon max IHP, limit motive force.

if (IndicatedHorsePowerHP >= MaxIndicatedHorsePowerHP)
{
TractiveForceN = N.FromLbf((MaxIndicatedHorsePowerHP * 375.0f) / pS.TopH(Me.ToMi(SpeedMpS)));
IndicatedHorsePowerHP = MaxIndicatedHorsePowerHP; // Set IHP to maximum value
IsCritTELimit = true; // Flag if limiting TE
}
else
{
IsCritTELimit = false; // Reset flag if limiting TE
}

DrawBarPullLbsF = N.ToLbf(Math.Abs(TractiveForceN) - LocoTenderFrictionForceN); // Locomotive drawbar pull is equal to motive force of locomotive (+ tender) - friction forces of locomotive (+ tender)
DrawBarPullLbsF = MathHelper.Clamp(DrawBarPullLbsF, 0, DrawBarPullLbsF); // clamp value so it doesn't go negative

DrawbarHorsePowerHP = (DrawBarPullLbsF * MpS.ToMpH(absSpeedMpS)) / 375.0f; // TE in this instance is a maximum, and not at the wheel???
DrawbarHorsePowerHP = MathHelper.Clamp(DrawbarHorsePowerHP, 0, DrawbarHorsePowerHP); // clamp value so it doesn't go negative

#region - Steam Adhesion Model Input for Steam Locomotives

// Based upon information presented on pg 276 of "Locomotive Operation - A Technical and Practical Analysis" by G. R. Henderson -
Expand Down Expand Up @@ -5377,7 +5371,21 @@ protected override void UpdateTractiveForce(float elapsedClockSeconds, float t,
TractiveForceN = 0.5f;
}

#endregion
#endregion


// Based upon max IHP, limit motive force.

if (IndicatedHorsePowerHP >= MaxIndicatedHorsePowerHP)
{
TractiveForceN = N.FromLbf((MaxIndicatedHorsePowerHP * 375.0f) / pS.TopH(Me.ToMi(SpeedMpS)));
IndicatedHorsePowerHP = MaxIndicatedHorsePowerHP; // Set IHP to maximum value
IsCritTELimit = true; // Flag if limiting TE
}
else
{
IsCritTELimit = false; // Reset flag if limiting TE
}

// Find the maximum TE for debug i.e. @ start and full throttle
if (absSpeedMpS < 1.0)
Expand Down Expand Up @@ -6310,6 +6318,14 @@ public override string GetStatus()

public override string GetDebugStatus()
{


DrawBarPullLbsF = N.ToLbf(Math.Abs(MotiveForceN) - LocoTenderFrictionForceN); // Locomotive drawbar pull is equal to motive force of locomotive (+ tender) - friction forces of locomotive (+ tender)
DrawBarPullLbsF = MathHelper.Clamp(DrawBarPullLbsF, 0, DrawBarPullLbsF); // clamp value so it doesn't go negative

DrawbarHorsePowerHP = (DrawBarPullLbsF * MpS.ToMpH(absSpeedMpS)) / 375.0f; // TE in this instance is a maximum, and not at the wheel???
DrawbarHorsePowerHP = MathHelper.Clamp(DrawbarHorsePowerHP, 0, DrawbarHorsePowerHP); // clamp value so it doesn't go negative

var status = new StringBuilder(base.GetDebugStatus());

status.AppendFormat("\n\n\t\t === {0} === \t\t\n", Simulator.Catalog.GetString("Key Inputs"));
Expand Down Expand Up @@ -6752,7 +6768,7 @@ public override string GetDebugStatus()
Simulator.Catalog.GetString("StartTE"),
FormatStrings.FormatForce(absStartTractiveEffortN, IsMetric),
Simulator.Catalog.GetString("TE"),
FormatStrings.FormatForce(N.FromLbf(DisplayTractiveEffortLbsF), IsMetric),
FormatStrings.FormatForce(MotiveForceN, IsMetric),
Simulator.Catalog.GetString("Draw"),
FormatStrings.FormatForce(N.FromLbf(DrawBarPullLbsF), IsMetric),
Simulator.Catalog.GetString("CritSpeed"),
Expand Down Expand Up @@ -6797,7 +6813,7 @@ public override string GetDebugStatus()
Simulator.Catalog.GetString("StartTE"),
FormatStrings.FormatForce(absStartTractiveEffortN, IsMetric),
Simulator.Catalog.GetString("TE"),
FormatStrings.FormatForce(N.FromLbf(DisplayTractiveEffortLbsF), IsMetric),
FormatStrings.FormatForce(MotiveForceN, IsMetric),
Simulator.Catalog.GetString("Draw"),
FormatStrings.FormatForce(N.FromLbf(DrawBarPullLbsF), IsMetric),
Simulator.Catalog.GetString("CritSpeed"),
Expand Down

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