Handle power limitation for diesels

Author: cesarBLG

Source/Orts.Simulation/Common/Scripting/PowerSupply/ElectricPowerSupply.cs

@@ -128,15 +128,6 @@ protected float PantographVoltageVDC
         /// </summary>
         protected void SetFilterVoltageV(float voltage) => EpsHost.FilterVoltageV = voltage;
 
-        /// <summary>
-        /// Maximum power of the locomotive
-        /// </summary>
-        protected float MaximumPowerW
-        {
-            get => EpsHost.MaximumPowerW;
-            set => EpsHost.MaximumPowerW = value;
-        }
-
         /// <summary>
         /// Sends an event to the circuit breaker
         /// </summary>

Source/Orts.Simulation/Common/Scripting/PowerSupply/LocomotivePowerSupply.cs

@@ -89,6 +89,15 @@ protected DieselEngineState CurrentHelperEnginesState()
             return state;
         }
 
+        /// <summary>
+        /// Power limit for traction motors
+        /// </summary>
+        protected float MaximumPowerW
+        {
+            get => LpsHost.MaximumPowerW;
+            set => LpsHost.MaximumPowerW = value;
+        }
+
         /// <summary>
         /// Current availability of the dynamic brake
         /// </summary>

Source/Orts.Simulation/Simulation/RollingStocks/MSTSDieselLocomotive.cs

@@ -685,27 +685,29 @@ protected override void UpdateTractiveForce(float elapsedClockSeconds, float t,
 
                 if (TractiveForceCurves == null)
                 {
-                    // This sets the maximum force of the locomotive, it will be adjusted down if it exceeds the max power of the locomotive.
-                    float maxForceN = Math.Min(t * MaxForceN * (1 - PowerReduction), AbsTractionSpeedMpS == 0.0f ? (t * MaxForceN * (1 - PowerReduction)) : (t * LocomotiveMaxRailOutputPowerW / AbsTractionSpeedMpS));
-
-                    // Maximum rail power is reduced by apparent throttle factor and the number of engines running (power ratio)
-                    float maxPowerW = LocomotiveMaxRailOutputPowerW * DieselEngineFractionPower * LocomotiveApparentThrottleSetting;
-
-                    // If unloading speed is in ENG file, and locomotive speed is greater then unloading speed, and less then max speed, then apply a decay factor to the power/force
-                    if (UnloadingSpeedMpS != 0 && AbsTractionSpeedMpS > UnloadingSpeedMpS && AbsTractionSpeedMpS < MaxSpeedMpS && !WheelSlip)
-                    {
-                        // use straight line curve to decay power to zero by 2 x unloading speed
-                        float unloadingspeeddecay = 1.0f - (1.0f / UnloadingSpeedMpS) * (AbsTractionSpeedMpS - UnloadingSpeedMpS);
-                        unloadingspeeddecay = MathHelper.Clamp(unloadingspeeddecay, 0.0f, 1.0f);  // Clamp decay within bounds
-                        maxPowerW *= unloadingspeeddecay;
-                    }
-
                     if (DieselEngines.HasGearBox)
                     {
                         TractiveForceN = DieselEngines.TractiveForceN;
                     }
                     else
                     {
+                        // This sets the maximum force of the locomotive, it will be adjusted down if it exceeds the max power of the locomotive.
+                        float maxForceN = Math.Min(t * MaxForceN * (1 - PowerReduction), AbsTractionSpeedMpS == 0.0f ? (t * MaxForceN * (1 - PowerReduction)) : (t * LocomotiveMaxRailOutputPowerW / AbsTractionSpeedMpS));
+
+                        // Maximum rail power is reduced by apparent throttle factor and the number of engines running (power ratio)
+                        float maxPowerW = LocomotiveMaxRailOutputPowerW * DieselEngineFractionPower * LocomotiveApparentThrottleSetting;
+
+                        if (DieselPowerSupply.MaximumPowerW > 0)
+                            maxPowerW = Math.Min(maxPowerW, DieselPowerSupply.MaximumPowerW * LocomotiveApparentThrottleSetting);
+
+                        // If unloading speed is in ENG file, and locomotive speed is greater then unloading speed, and less then max speed, then apply a decay factor to the power/force
+                        if (UnloadingSpeedMpS != 0 && AbsTractionSpeedMpS > UnloadingSpeedMpS && AbsTractionSpeedMpS < MaxSpeedMpS && !WheelSlip)
+                        {
+                            // use straight line curve to decay power to zero by 2 x unloading speed
+                            float unloadingspeeddecay = 1.0f - (1.0f / UnloadingSpeedMpS) * (AbsTractionSpeedMpS - UnloadingSpeedMpS);
+                            unloadingspeeddecay = MathHelper.Clamp(unloadingspeeddecay, 0.0f, 1.0f);  // Clamp decay within bounds
+                            maxPowerW *= unloadingspeeddecay;
+                        }
                         if (maxForceN * AbsSpeedMpS > maxPowerW)
                             maxForceN = maxPowerW / AbsTractionSpeedMpS;
 
@@ -725,6 +727,12 @@ protected override void UpdateTractiveForce(float elapsedClockSeconds, float t,
                     {
                         // Tractive force is read from Table using the apparent throttle setting, and then reduced by the number of engines running (power ratio)
                         TractiveForceN = TractiveForceCurves.Get(LocomotiveApparentThrottleSetting, AbsTractionSpeedMpS) * DieselEngineFractionPower * (1 - PowerReduction);
+                        if (DieselPowerSupply.MaximumPowerW > 0)
+                        {
+                            float maxPowerW = DieselPowerSupply.MaximumPowerW * t;
+                            if (TractiveForceN * AbsTractionSpeedMpS > maxPowerW)
+                                TractiveForceN = maxPowerW / AbsTractionSpeedMpS;
+                        }
                     }
 
                     if (TractiveForceN < 0 && !TractiveForceCurves.AcceptsNegativeValues())

Source/Orts.Simulation/Simulation/RollingStocks/MSTSLocomotive.cs

@@ -2513,9 +2513,9 @@ protected virtual void UpdateTractiveForce(float elapsedClockSeconds, float t, f
                 {
                     float maxForceN = MaxForceN * t * (1 - PowerReduction);
                     float maxPowerW = MaxPowerW;
-                    if (this is MSTSElectricLocomotive electric && electric.ElectricPowerSupply.MaximumPowerW > 0)
-                        maxPowerW = electric.ElectricPowerSupply.MaximumPowerW;
                     maxPowerW *= t * t * (1 - PowerReduction);
+                    if (this is MSTSElectricLocomotive electric && electric.ElectricPowerSupply.MaximumPowerW > 0)
+                        maxPowerW = Math.Min(maxPowerW, electric.ElectricPowerSupply.MaximumPowerW * t);
 
                     if (maxForceN * AbsTractionSpeedMpS > maxPowerW)
                         maxForceN = maxPowerW / AbsTractionSpeedMpS;
@@ -2532,7 +2532,7 @@ protected virtual void UpdateTractiveForce(float elapsedClockSeconds, float t, f
                     TractiveForceN = TractiveForceCurves.Get(t, AbsTractionSpeedMpS) * (1 - PowerReduction);
                     if (this is MSTSElectricLocomotive electric && electric.ElectricPowerSupply.MaximumPowerW > 0)
                     {
-                        float maxPowerW = electric.ElectricPowerSupply.MaximumPowerW * t * (1 - PowerReduction);
+                        float maxPowerW = electric.ElectricPowerSupply.MaximumPowerW * t;
                         if (TractiveForceN * AbsTractionSpeedMpS > maxPowerW)
                             TractiveForceN = maxPowerW / AbsTractionSpeedMpS;
                     }

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

@@ -42,8 +42,6 @@ public class ScriptedElectricPowerSupply : ScriptedLocomotivePowerSupply
         public float PantographVoltageVDC { get; set; }
         public float FilterVoltageV { get; set; } = 0;
 
-        public float MaximumPowerW;
-
         public ScriptedElectricPowerSupply(MSTSLocomotive locomotive) :
             base(locomotive)
         {

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

@@ -46,6 +46,7 @@ public abstract class ScriptedLocomotivePowerSupply : ILocomotivePowerSupply
 
         public PowerSupplyState MainPowerSupplyState { get; set; } = PowerSupplyState.PowerOff;
         public bool MainPowerSupplyOn => MainPowerSupplyState == PowerSupplyState.PowerOn;
+        public float MaximumPowerW;
         public bool DynamicBrakeAvailable { get; set; } = false;
         public float PowerSupplyDynamicBrakePercent { get; set; } = -1;
         public float MaximumDynamicBrakePowerW { get; set; } = 0;