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peternewellpeternewell
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Adjust counter pressure braking system
1 parent 2ef7f37 commit bed8323

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3 files changed

+88
-70
lines changed

3 files changed

+88
-70
lines changed

‎Source/Orts.Simulation/Simulation/RollingStocks/MSTSSteamLocomotive.cs‎

Lines changed: 83 additions & 69 deletions
Original file line numberDiff line numberDiff line change
@@ -171,8 +171,8 @@ public class MSTSSteamLocomotive : MSTSLocomotive
171171
float BoosterEngineSpeedRpM;
172172
bool BoosterAirisLow = false;
173173
int BoosterEngineNumber;
174-
175-
float SteamLocomotiveRetardingDynamicBrakeForceN = 0;
174+
175+
bool CounterPressureBrakingFitted = false;
176176

177177
/// <summary>
178178
/// Grate limit of locomotive exceedeed?
@@ -1059,6 +1059,10 @@ public override void Parse(string lowercasetoken, STFReader stf)
10591059
IsSelectGeared = String.Compare(typeString2, "Select") == 0;
10601060
break;
10611061

1062+
case "engine(ortscounterpressurebraking":
1063+
CounterPressureBrakingFitted = stf.ReadBoolBlock(false);
1064+
break;
1065+
10621066
case "engine(ortsbattery(mode":
10631067
case "engine(ortsbattery(delay":
10641068
case "engine(ortsbattery(defaulton":
@@ -1107,6 +1111,7 @@ public override void Copy(MSTSWagon copy)
11071111
EjectorLargeSteamConsumptionLbpS = locoCopy.EjectorLargeSteamConsumptionLbpS;
11081112
ShovelMassKG = locoCopy.ShovelMassKG;
11091113
GearedTractiveEffortFactor = locoCopy.GearedTractiveEffortFactor;
1114+
CounterPressureBrakingFitted = locoCopy.CounterPressureBrakingFitted;
11101115
TractiveEffortFactor = locoCopy.TractiveEffortFactor;
11111116
MaxTenderFuelMassKG = locoCopy.MaxTenderFuelMassKG;
11121117
MaxLocoTenderWaterMassKG = locoCopy.MaxLocoTenderWaterMassKG;
@@ -2523,7 +2528,6 @@ public override void Update(float elapsedClockSeconds)
25232528

25242529
if (SteamEngines[i].AuxiliarySteamEngineType != SteamEngine.AuxiliarySteamEngineTypes.Booster)
25252530
{
2526-
UpdateCounterPressure(elapsedClockSeconds, cutoff, i);
25272531
UpdateCylinders(elapsedClockSeconds, throttle, cutoff, absSpeedMpS, i);
25282532
}
25292533
else if (SteamEngines[i].AuxiliarySteamEngineType == SteamEngine.AuxiliarySteamEngineTypes.Booster) // Booster Engine
@@ -4876,58 +4880,9 @@ private void UpdateSuperHeat()
48764880
}
48774881

48784882
SuperheaterSteamUsageFactor = MathHelper.Clamp(SuperheaterSteamUsageFactor, 0.60f, SuperheaterSteamUsageFactor); // ensure factor does not go below 0.6, as this represents base steam consumption by the cylinders.
4879-
4880-
}
4881-
4882-
/// <summary>
4883-
/// Calculate the counter pressure to be used by a locomotive as a braking effect
4884-
/// To do this we first calculate the MEP air pressure of compressed air with each stroke, then we calculate the resulting "resisting" tractive force
4885-
/// </summary>
4886-
private void UpdateCounterPressure(float elapsedClockSeconds, float cutoff, int numberofengine)
4887-
{
4888-
SteamLocomotiveRetardingDynamicBrakeForceN = 0;
4889-
4890-
float currentDynamicBrakeFraction = DynamicBrakePercent / 100;
4891-
4892-
if (currentDynamicBrakeFraction > 0 && absSpeedMpS >0)
4893-
{
4894-
float CylinderVolumePoint_compression = (currentDynamicBrakeFraction * Me.ToIn(SteamEngines[numberofengine].CylindersStrokeM)) + CylinderClearancePC;
4895-
float CylinderVolumePoint_release = (Me.ToIn(SteamEngines[numberofengine].CylindersStrokeM) + 2 * CylinderClearancePC) - CylinderVolumePoint_compression;
4896-
4897-
// Trace.TraceInformation("Vol-release {0} Vol-compression {1} Stroke {2}", CylinderVolumePoint_release, CylinderVolumePoint_compression, Me.ToIn(SteamEngines[numberofengine].CylindersStrokeM));
4898-
4899-
// Ratio of compression = stroke during compression = stroke @ start of compression / stroke and end of compression
4900-
float CylinderRatio_compression = CylinderVolumePoint_compression / CylinderClearancePC;
4901-
float CylinderRatio_release = CylinderVolumePoint_compression / (Me.ToIn(SteamEngines[numberofengine].CylindersStrokeM) + 2 * CylinderClearancePC);
4902-
4903-
float CompMeanPressure_compressionAtmPSI = OneAtmospherePSI * CylinderRatio_compression * ((float)Math.Log(CylinderRatio_compression, 10) / (CylinderRatio_compression - 1.0f));
4904-
float CompMeanPressure_releaseAtmPSI = CompMeanPressure_compressionAtmPSI * CylinderRatio_release * ((float)Math.Log(CylinderRatio_release) / (CylinderRatio_release - 1.0f));
4905-
4906-
// Trace.TraceInformation("MEPcomp {0} Log {1} CompRatio {2}", CompMeanPressure_compressionAtmPSI, (float)Math.Log(CylinderRatio_compression), CylinderRatio_compression);
4907-
4908-
float CylinderWork_compression_InLbs = CompMeanPressure_compressionAtmPSI * CylinderVolumePoint_compression;
4909-
float CylinderWork_release_InLbs = CompMeanPressure_releaseAtmPSI * CylinderVolumePoint_release;
4910-
4911-
// Trace.TraceInformation("Workc {0} Workr {1} Pc {2} Pr {3}", CylinderWork_compression_InLbs, CylinderWork_release_InLbs, CompMeanPressure_compressionAtmPSI, CompMeanPressure_releaseAtmPSI);
4912-
4913-
float TotalWorkCounterPressure = CylinderWork_compression_InLbs + CylinderWork_release_InLbs;
4914-
4915-
float CounterPressureMEP = TotalWorkCounterPressure / Me.ToIn(SteamEngines[numberofengine].CylindersStrokeM);
4916-
4917-
// Calculate tractive retarding force
4918-
SteamLocomotiveRetardingDynamicBrakeForceN = N.FromLbf(CounterPressureMEP * Me.ToIn(SteamEngines[numberofengine].CylindersDiameterM) * Me.ToIn(SteamEngines[numberofengine].CylindersDiameterM) * Me.ToIn(SteamEngines[numberofengine].CylindersStrokeM) / Me.ToIn(SteamEngines[numberofengine].AttachedAxle.CogWheelRadiusM));
4919-
4920-
// Trace.TraceInformation("CogRetardForce {0} throttle {1} MEP {2} Ratio-Comp {3} Ratio-Rel {4}", N.ToLbf(SteamLocomotiveRetardingDynamicBrakeForceN), throttle, CounterPressureMEP, CylinderRatio_compression, CylinderRatio_release);
4921-
}
4922-
else
4923-
{
4924-
SteamLocomotiveRetardingDynamicBrakeForceN = 0;
4925-
}
4926-
4927-
49284883
}
49294884

4930-
private void UpdateCylinders(float elapsedClockSeconds, float throttle, float cutoff, float absSpeedMpS, int numberofengine)
4885+
private void UpdateCylinders(float elapsedClockSeconds, float throttle, float cutoff, float absSpeedMpS, int numberofengine)
49314886
{
49324887
// Calculate speed of locomotive in wheel rpm - used to determine changes in performance based upon speed.
49334888
SteamEngines[numberofengine].DriveWheelRevRpS = absSpeedMpS / (2.0f * MathHelper.Pi * SteamEngines[numberofengine].AttachedAxle.WheelRadiusM);
@@ -6043,6 +5998,58 @@ private void UpdateCylinders(float elapsedClockSeconds, float throttle, float cu
60435998

60445999
SteamReleasePressure_AtmPSI = SteamEngines[numberofengine].Pressure_c_AtmPSI; // for steam and smoke effects
60456000

6001+
6002+
// Calculate the counter pressure to be used by a locomotive as a braking effect
6003+
// To do this we first calculate the MEP air pressure of compressed air with each stroke, then we calculate the resulting "resisting" tractive force
6004+
6005+
SteamEngines[numberofengine].CylinderCounterPressureBrakeForceN = 0;
6006+
6007+
float currentDynamicBrakeFraction = DynamicBrakePercent / 100;
6008+
6009+
if (currentDynamicBrakeFraction > 0 && absSpeedMpS > 0)
6010+
{
6011+
float CylinderVolumePoint_compression = (currentDynamicBrakeFraction * Me.ToIn(SteamEngines[numberofengine].CylindersStrokeM)) + CylinderClearancePC;
6012+
float CylinderVolumePoint_release = (Me.ToIn(SteamEngines[numberofengine].CylindersStrokeM) + 2 * CylinderClearancePC) - CylinderVolumePoint_compression;
6013+
6014+
// Trace.TraceInformation("Vol-release {0} Vol-compression {1} Stroke {2}", CylinderVolumePoint_release, CylinderVolumePoint_compression, Me.ToIn(SteamEngines[numberofengine].CylindersStrokeM));
6015+
6016+
// Ratio of compression = stroke during compression = stroke @ start of compression / stroke and end of compression
6017+
float CylinderRatio_compression = CylinderVolumePoint_compression / CylinderClearancePC;
6018+
float CylinderRatio_release = CylinderVolumePoint_compression / (Me.ToIn(SteamEngines[numberofengine].CylindersStrokeM) + 2 * CylinderClearancePC);
6019+
6020+
float CompMeanPressure_compressionAtmPSI = OneAtmospherePSI * CylinderRatio_compression * ((float)Math.Log(CylinderRatio_compression, 10) / (CylinderRatio_compression - 1.0f));
6021+
float CompMeanPressure_releaseAtmPSI = CompMeanPressure_compressionAtmPSI * CylinderRatio_release * ((float)Math.Log(CylinderRatio_release) / (CylinderRatio_release - 1.0f));
6022+
6023+
// Trace.TraceInformation("MEPcomp {0} Log {1} CompRatio {2}", CompMeanPressure_compressionAtmPSI, (float)Math.Log(CylinderRatio_compression), CylinderRatio_compression);
6024+
6025+
float CylinderWork_compression_InLbs = CompMeanPressure_compressionAtmPSI * CylinderVolumePoint_compression;
6026+
float CylinderWork_release_InLbs = CompMeanPressure_releaseAtmPSI * CylinderVolumePoint_release;
6027+
6028+
// Trace.TraceInformation("Workc {0} Workr {1} Pc {2} Pr {3}", CylinderWork_compression_InLbs, CylinderWork_release_InLbs, CompMeanPressure_compressionAtmPSI, CompMeanPressure_releaseAtmPSI);
6029+
6030+
float TotalWorkCounterPressure = CylinderWork_compression_InLbs + CylinderWork_release_InLbs;
6031+
6032+
float CounterPressureMEP = TotalWorkCounterPressure / Me.ToIn(SteamEngines[numberofengine].CylindersStrokeM);
6033+
6034+
// Assume no impact of "return" stroke as air is being drawn into cylinder
6035+
6036+
// Calculate tractive retarding force
6037+
SteamEngines[numberofengine].CylinderCounterPressureBrakeForceN = N.FromLbf(CounterPressureMEP * Me.ToIn(SteamEngines[numberofengine].CylindersDiameterM) * Me.ToIn(SteamEngines[numberofengine].CylindersDiameterM) * Me.ToIn(SteamEngines[numberofengine].CylindersStrokeM) / Me.ToIn(SteamEngines[numberofengine].AttachedAxle.CogWheelRadiusM));
6038+
6039+
// Trace.TraceInformation("CogRetardForce {0} throttle {1} MEP {2} Ratio-Comp {3} Ratio-Rel {4}", N.ToLbf(SteamLocomotiveRetardingDynamicBrakeForceN), throttle, CounterPressureMEP, CylinderRatio_compression, CylinderRatio_release);
6040+
}
6041+
else
6042+
{
6043+
SteamEngines[numberofengine].CylinderCounterPressureBrakeForceN = 0;
6044+
}
6045+
6046+
6047+
6048+
6049+
6050+
6051+
6052+
60466053
}
60476054

60486055

@@ -6562,6 +6569,7 @@ private void UpdateSteamTractiveForce(float elapsedClockSeconds, float locomotiv
65626569
protected override void UpdateTractiveForce(float elapsedClockSeconds, float locomotivethrottle, float AbsSpeedMpS, float AbsWheelSpeedMpS)
65636570
{
65646571
TractiveForceN = 0; // reset tractiveforceN in preparation to calculating a new value
6572+
DynamicBrakeForceN = 0;
65656573
if (!Simulator.UseAdvancedAdhesion && Simulator.Settings.SimpleControlPhysics)
65666574
{
65676575
// Simple adhesion
@@ -6587,11 +6595,31 @@ protected override void UpdateTractiveForce(float elapsedClockSeconds, float loc
65876595
{
65886596
ApplyDirectionToTractiveForce(ref SteamEngines[i].RealTractiveForceN, i);
65896597

6590-
TractiveForceN += SteamEngines[i].RealTractiveForceN;
6598+
TractiveForceN += SteamEngines[i].RealTractiveForceN + DynamicBrakeForceN;
65916599

65926600
if (Simulator.UseAdvancedAdhesion && !Simulator.Settings.SimpleControlPhysics)
65936601
{
65946602
SteamEngines[i].AttachedAxle.DriveForceN = SteamEngines[i].RealTractiveForceN;
6603+
6604+
// Counter Pressure braking system
6605+
6606+
if (DynamicBrakePercent > 0 && CounterPressureBrakingFitted && absSpeedMpS > 0.1)
6607+
{
6608+
DynamicBrakeForceN += SteamEngines[i].CylinderCounterPressureBrakeForceN;
6609+
TractiveForceN -= (SpeedMpS > 0 ? 1 : SpeedMpS < 0 ? -1 : Direction == Direction.Reverse ? -1 : 1) * DynamicBrakeForceN;
6610+
SteamEngines[i].AttachedAxle.DriveForceN = SteamEngines[i].RealTractiveForceN;
6611+
}
6612+
else
6613+
{
6614+
DynamicBrakeForceN = 0;
6615+
}
6616+
6617+
if (DynamicBrakeForceN > 0)
6618+
{
6619+
6620+
SteamEngines[i].AttachedAxle.DriveForceN = DynamicBrakeForceN;
6621+
}
6622+
65956623
UpdateAxleDriveForce();
65966624

65976625
SteamEngines[i].DisplayTractiveForceN = SteamEngines[i].AverageTractiveForceN;
@@ -6641,25 +6669,12 @@ protected override void UpdateTractiveForce(float elapsedClockSeconds, float loc
66416669
MaxSpeedMpS = Me.FromMi(pS.FrompH(MaxLocoSpeedMpH)); // Note this is not the true max velocity of the locomotive, but the speed at which max HP is reached
66426670

66436671
// Set tractive force to zero if throttle is closed
6644-
if (locomotivethrottle < 0.001)
6672+
if (locomotivethrottle < 0.001 && !CounterPressureBrakingFitted)
66456673
{
66466674
TractiveForceN = 0;
66476675
}
6648-
6649-
// if (DynamicBrakePercent > 0 && DynamicBrake)
6650-
6651-
if (DynamicBrakePercent > 0)
6652-
{
6653-
DynamicBrakeForceN = SteamLocomotiveRetardingDynamicBrakeForceN;
6654-
}
6655-
else
6656-
{
6657-
DynamicBrakeForceN = 0;
6658-
}
6659-
66606676
}
66616677

6662-
66636678
/// <summary>
66646679
/// This function applies a sign to the motive force as a function of the direction of the train.
66656680
/// </summary>
@@ -8443,7 +8458,6 @@ public override string GetDebugStatus()
84438458
FormatStrings.mm);
84448459
}
84458460

8446-
84478461
if (SteamIsAuxTenderCoupled)
84488462
{
84498463
status.AppendFormat("{0}\t{1}\t{2}\t{3:N0}%\t{4}\t{5}\t\t{6:N0}%\t{7}\t{8}\t\t{9}\t{10}\t\t{11}\t{12:N0}\t{13}\t{14:N0}\n",

‎Source/Orts.Simulation/Simulation/RollingStocks/SubSystems/PowerSupplies/SteamEngine.cs‎

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -361,6 +361,11 @@ public enum AuxiliarySteamEngineTypes
361361
/// </summary>
362362
public float DisplayTractiveForceN;
363363

364+
/// <summary>
365+
/// Steam Engine counter pressure barking force
366+
/// </summary>
367+
public float CylinderCounterPressureBrakeForceN;
368+
364369
/// <summary>
365370
/// Steam Engine maximum indicated horsepower
366371
/// </summary>

‎Source/Orts.Simulation/Simulation/RollingStocks/SubSystems/PowerTransmissions/Axle.cs‎

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -912,7 +912,6 @@ public void Parse(STFReader stf)
912912
break;
913913
case "cogwheelfitted":
914914
CogWheelFitted = stf.ReadBoolBlock(false);
915-
Trace.TraceInformation("CogWheel - {0}", CogWheelFitted);
916915
break;
917916
case "cogwheelradius":
918917
CogWheelRadiusM = stf.ReadFloatBlock(STFReader.UNITS.Distance, null);

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