Improvements for air brakes #3 - Emergency valves

Source/Documentation/Manual/physics.rst

@@ -2944,6 +2944,8 @@ MaxAuxilaryChargingRate and EmergencyResChargingRate.
 .. index::
    single: BrakePipeVolume
    single: ORTSEmergencyValveActuationRate
+   single: ORTSEmergencyDumpValveRate
+   single: ORTSEmergencyDumpValveTimer
    single: ORTSMainResPipeAuxResCharging
    single: ORTSMainResChargingRate
    single: ORTSEngineBrakeReleaseRate
@@ -2972,6 +2974,11 @@ MaxAuxilaryChargingRate and EmergencyResChargingRate.
   brake actuation of the triple valve. If the pressure in the brake pipe
   decreases at a higher rate than specified, the triple valve will switch to
   emergency mode.
+- ``Wagon(ORTSEmergencyDumpValveRate)``-- Rate at which BP is locally discharged
+  at every wagon during an emergency brake application.
+- ``Wagon(ORTSEmergencyDumpValveTimer)``-- Timer for emergency dump valve to close
+  after it is activated. If set to 0, it will close as soon as BP is discharged.
+  Default value will prevent BP from being charged for 2 minutes.
 - ``Wagon(ORTSMainResPipeAuxResCharging`` -- Boolean value that indicates,
   for twin pipe systems, if the main reservoir pipe is used for charging the auxiliary
   reservoirs. If set to false, the main reservoir pipe will not be used

Source/Documentation/Manual/sound.rst

@@ -403,6 +403,9 @@ Trigger       Function
 243           GenericItem2Off
 =========     =====================================
 
+Trigger 252 is activated when the braking system detects an
+emergency brake application and starts venting air from the Brake Pipe.
+
 Variable Triggers
 -----------------
 

Source/Orts.Simulation/Common/Events.cs

@@ -255,6 +255,7 @@ public enum Event
 
         OverchargeBrakingOn,
         OverchargeBrakingOff,
+        EmergencyVentValveOn,
 
         // Cruise Control
         LeverFromZero,
@@ -523,6 +524,7 @@ public static Event From(Source source, int eventID)
 
                         case 250: return Event.OverchargeBrakingOn;
                         case 251: return Event.OverchargeBrakingOff;
+                        case 252: return Event.EmergencyVentValveOn;
 
                         // Cruise Control
                         case 298: return Event.LeverFromZero;

Source/Orts.Simulation/Simulation/RollingStocks/SubSystems/Brakes/MSTS/AirSinglePipe.cs

@@ -51,6 +51,9 @@ public class AirSinglePipe : MSTSBrakeSystem
         protected float MaxAuxilaryChargingRatePSIpS = 1.684f;
         protected float BrakeInsensitivityPSIpS = 0.07f;
         protected float EmergencyValveActuationRatePSIpS = 0;
+        protected float EmergencyDumpValveRatePSIpS = 0;
+        protected float EmergencyDumpValveTimerS = 120;
+        protected float? EmergencyDumpStartTime;
         protected float EmergResChargingRatePSIpS = 1.684f;
         protected float EmergAuxVolumeRatio = 1.4f;
         protected string DebugType = string.Empty;
@@ -116,6 +119,8 @@ public override void InitializeFromCopy(BrakeSystem copy)
             MaxAuxilaryChargingRatePSIpS = thiscopy.MaxAuxilaryChargingRatePSIpS;
             BrakeInsensitivityPSIpS = thiscopy.BrakeInsensitivityPSIpS;
             EmergencyValveActuationRatePSIpS = thiscopy.EmergencyValveActuationRatePSIpS;
+            EmergencyDumpValveRatePSIpS = thiscopy.EmergencyDumpValveRatePSIpS;
+            EmergencyDumpValveTimerS = thiscopy.EmergencyDumpValveTimerS;
             EmergResChargingRatePSIpS = thiscopy.EmergResChargingRatePSIpS;
             EmergAuxVolumeRatio = thiscopy.EmergAuxVolumeRatio;
             TwoPipes = thiscopy.TwoPipes;
@@ -232,6 +237,8 @@ public override void Parse(string lowercasetoken, STFReader stf)
                 case "wagon(brakepipevolume": BrakePipeVolumeM3 = Me3.FromFt3(stf.ReadFloatBlock(STFReader.UNITS.VolumeDefaultFT3, null)); break;
                 case "wagon(ortsbrakeinsensitivity": BrakeInsensitivityPSIpS = stf.ReadFloatBlock(STFReader.UNITS.PressureRateDefaultPSIpS, 0.07f); break;
                 case "wagon(ortsemergencyvalveactuationrate": EmergencyValveActuationRatePSIpS = stf.ReadFloatBlock(STFReader.UNITS.PressureRateDefaultPSIpS, 15f); break;
+                case "wagon(ortsemergencydumpvalverate": EmergencyDumpValveRatePSIpS = stf.ReadFloatBlock(STFReader.UNITS.PressureRateDefaultPSIpS, 15f); break;
+                case "wagon(ortsemergencydumpvalvetimer": EmergencyDumpValveTimerS = stf.ReadFloatBlock(STFReader.UNITS.Time, 120.0f); break;
                 case "wagon(ortsmainrespipeauxrescharging": MRPAuxResCharging = this is AirTwinPipe && stf.ReadBoolBlock(true); break;
             }
         }
@@ -307,7 +314,10 @@ public override void Initialize(bool handbrakeOn, float maxPressurePSI, float fu
             CylPressurePSI = AutoCylPressurePSI = immediateRelease ? 0 : Math.Min((maxPressurePSI - BrakeLine1PressurePSI) * AuxCylVolumeRatio, MaxCylPressurePSI);
             AuxResPressurePSI = Math.Max(TwoPipes ? maxPressurePSI : maxPressurePSI - AutoCylPressurePSI / AuxCylVolumeRatio, BrakeLine1PressurePSI);
             if ((Car as MSTSWagon).EmergencyReservoirPresent)
+            {
                 EmergResPressurePSI = Math.Max(AuxResPressurePSI, maxPressurePSI);
+                if (EmergencyValveActuationRatePSIpS == 0) EmergencyValveActuationRatePSIpS = 15;
+            }
             TripleValveState = AutoCylPressurePSI < 1 ? ValveState.Release : ValveState.Lap;
             HoldingValve = ValveState.Release;
             HandbrakePercent = handbrakeOn & (Car as MSTSWagon).HandBrakePresent ? 100 : 0;
@@ -340,23 +350,25 @@ public override void InitializeMoving ()
 
         public void UpdateTripleValveState(float elapsedClockSeconds)
         {
+            var prevState = TripleValveState;
             var valveType = (Car as MSTSWagon).BrakeValve;
+            bool disableGradient = !(Car.Train.LeadLocomotive is MSTSLocomotive) && Car.Train.TrainType != Orts.Simulation.Physics.Train.TRAINTYPE.STATIC;
             if (valveType == MSTSWagon.BrakeValveType.Distributor)
             {
                 float targetPressurePSI = (ControlResPressurePSI - BrakeLine1PressurePSI) * AuxCylVolumeRatio;
-                if (targetPressurePSI > AutoCylPressurePSI && EmergencyValveActuationRatePSIpS > 0 && (prevBrakePipePressurePSI - BrakeLine1PressurePSI) > Math.Max(elapsedClockSeconds, 0.0001f) * EmergencyValveActuationRatePSIpS)
+                if (!disableGradient && targetPressurePSI > AutoCylPressurePSI && EmergencyValveActuationRatePSIpS > 0 && (prevBrakePipePressurePSI - BrakeLine1PressurePSI) > Math.Max(elapsedClockSeconds, 0.0001f) * EmergencyValveActuationRatePSIpS)
                     TripleValveState = ValveState.Emergency;
                 else if (targetPressurePSI < AutoCylPressurePSI - (TripleValveState != ValveState.Release ? 2.2f : 0f)
                     || targetPressurePSI < 2.2f) // The latter is a UIC regulation (0.15 bar)
                     TripleValveState = ValveState.Release;
                 else if (TripleValveState != ValveState.Emergency && targetPressurePSI > AutoCylPressurePSI + (TripleValveState != ValveState.Apply ? 2.2f : 0f))
                     TripleValveState = ValveState.Apply;
-                else
+                else if (TripleValveState != ValveState.Emergency)
                     TripleValveState = ValveState.Lap;
             }
             else if (valveType == MSTSWagon.BrakeValveType.TripleValve || valveType == MSTSWagon.BrakeValveType.DistributingValve)
             {
-                if (BrakeLine1PressurePSI < AuxResPressurePSI - 1 && EmergencyValveActuationRatePSIpS > 0 && (prevBrakePipePressurePSI - BrakeLine1PressurePSI) > Math.Max(elapsedClockSeconds, 0.0001f) * EmergencyValveActuationRatePSIpS)
+                if (!disableGradient && BrakeLine1PressurePSI < AuxResPressurePSI - 1 && EmergencyValveActuationRatePSIpS > 0 && (prevBrakePipePressurePSI - BrakeLine1PressurePSI) > Math.Max(elapsedClockSeconds, 0.0001f) * EmergencyValveActuationRatePSIpS)
                     TripleValveState = ValveState.Emergency;
                 else if (BrakeLine1PressurePSI > AuxResPressurePSI + 1)
                     TripleValveState = ValveState.Release;
@@ -371,6 +383,15 @@ public void UpdateTripleValveState(float elapsedClockSeconds)
             {
                 TripleValveState = ValveState.Release;
             }
+            if (TripleValveState == ValveState.Emergency)
+            {
+                if (prevState != ValveState.Emergency)
+                {
+                    EmergencyDumpStartTime = (float)Car.Simulator.GameTime;
+                    Car.SignalEvent(Event.EmergencyVentValveOn);
+                }
+            }
+            else EmergencyDumpStartTime = null;
             prevBrakePipePressurePSI = BrakeLine1PressurePSI;
         }
 
@@ -440,6 +461,20 @@ public override void Update(float elapsedClockSeconds)
                         EmergResPressurePSI -= dp;
                         AuxResPressurePSI += dp * EmergAuxVolumeRatio;
                     }
+                    if (EmergencyDumpValveTimerS == 0)
+                    {
+                        if (BrakeLine1PressurePSI < 1) EmergencyDumpStartTime = null;
+                    }
+                    else if (Car.Simulator.GameTime - EmergencyDumpStartTime > EmergencyDumpValveTimerS)
+                    {
+                        EmergencyDumpStartTime = null;
+                    }
+                    if (EmergencyDumpValveRatePSIpS > 0 && EmergencyDumpStartTime != null)
+                    {
+                        BrakeLine1PressurePSI -= elapsedClockSeconds * EmergencyDumpValveRatePSIpS;
+                        if (BrakeLine1PressurePSI < 0)
+                            BrakeLine1PressurePSI = 0;
+                    }
                 }
             }