added valves display

Components/EngineCylinder.cs

@@ -17,17 +17,19 @@ namespace FluidSim.Core
 
         // ---- Exhaust valve ----
         private double exhMaxOrificeArea;
-        private double exhValveOpenStart = 120.0 * Math.PI / 180.0;   // 120° (EVO)
+        private double exhValveOpenStart = 130.0 * Math.PI / 180.0;
-        private double exhValveOpenEnd   = 480.0 * Math.PI / 180.0;   // 480° (EVC)
+        private double exhValveOpenEnd   = 390.0 * Math.PI / 180.0;
         private double exhValveRampWidth = 30.0  * Math.PI / 180.0;
         public double ExhaustOrificeArea => ExhaustValveLift() * exhMaxOrificeArea;
+        public double ExhaustValveLiftCurrent => ExhaustValveLift();
 
         // ---- Intake valve ----
         private double intMaxOrificeArea;
-        private double intValveOpenStart = 380.0 * Math.PI / 180.0;   // 380° (IVO)
+        private double intValveOpenStart = 340.0 * Math.PI / 180.0;
-        private double intValveOpenEnd   = 560.0 * Math.PI / 180.0;   // 560° (IVC)
+        private double intValveOpenEnd   = 600.0 * Math.PI / 180.0;
         private double intValveRampWidth = 30.0  * Math.PI / 180.0;
         public double IntakeOrificeArea => IntakeValveLift() * intMaxOrificeArea;
+        public double IntakeValveLiftCurrent => IntakeValveLift();
 
         // ---- Combustion ----
         public double TargetPeakPressure { get; set; } = 50.0 * 101325.0;
@@ -70,8 +72,8 @@ namespace FluidSim.Core
             this.stroke = stroke;
             conRodLength = 2.0 * stroke;
             this.compressionRatio = compressionRatio;
-            exhMaxOrificeArea = exhPipeArea;
+            exhMaxOrificeArea = exhPipeArea * 0.5;
-            intMaxOrificeArea = intPipeArea;
+            intMaxOrificeArea = intPipeArea * 0.5;
             pistonArea = Math.PI / 4.0 * bore * bore;
 
             V_disp = pistonArea * stroke;

Components/Nozzleflow.cs

@@ -0,0 +1,46 @@
+using System;
+
+namespace FluidSim.Components
+{
+    public static class NozzleFlow
+    {
+        /// <summary>
+        /// Computes the nozzle‑exit primitive state and mass flow rate from a
+        /// volume to a pipe, using isentropic relations. Follows ensim4's flow() logic.
+        /// </summary>
+        public static void Compute(double Pt_high, double Tt_high,
+                                   double P_low, double gamma, double R, double area,
+                                   out double rhoExit, out double uExit,
+                                   out double pExit, out double mdot)
+        {
+            double gm1 = gamma - 1.0;
+            double Pt_over_Ps = Pt_high / P_low;
+
+            // Mach number (subsonic, clamped to 1)
+            double M = Math.Sqrt(Math.Max(0.0,
+                (2.0 / gm1) * (Math.Pow(Pt_over_Ps, gm1 / gamma) - 1.0)));
+            if (M > 1.0) M = 1.0;
+
+            double T_star = Tt_high / (1.0 + 0.5 * gm1 * M * M);
+            double a_star = Math.Sqrt(gamma * R * T_star);
+            double u_star = M * a_star;
+            pExit = Pt_high * Math.Pow(1.0 + 0.5 * gm1 * M * M, -gamma / gm1);
+            rhoExit = pExit / (R * T_star);
+            uExit = u_star;   // positive away from high‑pressure side
+            mdot = rhoExit * uExit * area;
+        }
+
+        /// <summary>
+        /// Ambient cell for non‑reflecting open end (ensim4 calc_ambient_cell).
+        /// </summary>
+        public static void ComputeAmbientCell(double rhoInt, double uInt, double pInt,
+                                               double pAmbient, double gamma,
+                                               out double rhoAmb, out double uAmb,
+                                               out double pAmb)
+        {
+            pAmb = pAmbient;
+            uAmb = uInt;
+            rhoAmb = rhoInt * Math.Pow(pAmb / pInt, 1.0 / gamma);
+        }
+    }
+}

Program.cs

@@ -25,7 +25,7 @@ public class Program
     // Throttle smoothing
     private static double targetThrottle = 0.0;   // 1.0 when W is pressed, 0.0 otherwise
     private static double currentThrottle = 0.0;
-    private const double ThrottleSmoothing = 40.0; // rate of change
+    private const double ThrottleSmoothing = 20.0; // rate of change
 
     private static volatile bool running = true;
 

Scenarios/EngineScenario.cs

@@ -31,7 +31,7 @@ namespace FluidSim.Core
         private const int LogInterval = 1000;
 
         public double Throttle { get; set; } = 0.15;
-        private const double FullLoadPeakPressure = 60.0 * Units.bar;
+        private const double FullLoadPeakPressure = 140.0 * Units.bar;
 
         public override void Initialize(int sampleRate)
         {
@@ -41,29 +41,29 @@ namespace FluidSim.Core
             crankshaft = new Crankshaft(initialRPM: 2000.0)
             {
                 Inertia = 0.05,
-                FrictionConstant = 0.5,
+                FrictionConstant = 0.2,
-                FrictionViscous = 0.01
+                FrictionViscous = 0.025
             };
 
             // Exhaust pipe (longer, larger)
-            double exhLength = 1;
+            double exhLength = 0.5;
-            double exhRadius = 0.02;
+            double exhRadius = 1.5 * Units.cm;
             exhPipeArea = Math.PI * exhRadius * exhRadius;
-            exhaustPipe = new Pipe1D(exhLength, exhPipeArea, sampleRate, forcedCellCount: 100);
+            exhaustPipe = new Pipe1D(exhLength, exhPipeArea, sampleRate, forcedCellCount: 30);
             exhaustPipe.SetUniformState(1.225, 0.0, AmbientPressure);
             exhaustPipe.DampingMultiplier = 0.0;
             exhaustPipe.EnergyRelaxationRate = 100.0f;
 
             // Intake pipe (shorter, narrower)
-            double intLength = 1;
+            double intLength = 0.1;
-            double intRadius = 0.01;
+            double intRadius = 1 * Units.cm;
             intPipeArea = Math.PI * intRadius * intRadius;
-            intakePipe = new Pipe1D(intLength, intPipeArea, sampleRate, forcedCellCount: 50);
+            intakePipe = new Pipe1D(intLength, intPipeArea, sampleRate, forcedCellCount: 10);
             intakePipe.SetUniformState(1.225, 0.0, AmbientPressure);
 
             // Cylinder (starts at BDC, fresh charge)
             engineCyl = new EngineCylinder(crankshaft,
-                bore: 0.065, stroke: 0.0565, compressionRatio: 8.0,
+                bore: 56 * Units.mm, stroke: 57 * Units.mm, compressionRatio: 9.5,
                 exhPipeArea: exhPipeArea, intPipeArea: intPipeArea, sampleRate: sampleRate);
             engineCyl.ignition = true;
 
@@ -107,7 +107,9 @@ namespace FluidSim.Core
 
         public override float Process()
         {
-            double throttle = Math.Clamp(Throttle, 0.2, 1.0);
+            double idleThrottle = 0.1;
+            if (crankshaft.AngularVelocity < 80) idleThrottle = 0.2;
+            double throttle = Math.Clamp(Throttle, idleThrottle, 1.0);
             double targetPressure = throttle * FullLoadPeakPressure;
             engineCyl.TargetPeakPressure = targetPressure;
 
@@ -251,12 +253,36 @@ namespace FluidSim.Core
             };
             target.Draw(pistonRect);
 
+            // ---------- NEW: Valve lift indicators ----------
+            float barWidth = 30f;
+            float barHeight = 10f;
+            float exhLift = (float)engineCyl.ExhaustValveLiftCurrent;
+            float intLift = (float)engineCyl.IntakeValveLiftCurrent;
+
+            // Exhaust valve indicator (right side of cylinder)
+            var exhBar = new RectangleShape(new Vector2f(barWidth, barHeight))
+            {
+                Position = new Vector2f(cylRect.Position.X + cylW - 10,
+                                         cylRect.Position.Y - 20 - exhLift * 20),
+                FillColor = new Color(200, 200, 200)
+            };
+            target.Draw(exhBar);
+
+            // Intake valve indicator (left side of cylinder)
+            var intBar = new RectangleShape(new Vector2f(barWidth, barHeight))
+            {
+                Position = new Vector2f(cylRect.Position.X - 20,
+                                         cylRect.Position.Y - 20 - intLift * 20),
+                FillColor = new Color(200, 200, 200)
+            };
+            target.Draw(intBar);
+
             // ---- Exhaust pipe (rightwards) ----
-            DrawPipe(target, exhaustPipe, startX: 280f, endX: winW - 60f, centerY,
+            DrawPipe(target, exhaustPipe, startX: 280f, endX: winW - 60f, centerY + 10 - cylRect.Size.Y / 2,
                      T_ambient, T_hot, T_cold, R, NormaliseTemperature, true);
 
             // ---- Intake pipe (leftwards) ----
-            DrawPipe(target, intakePipe, startX: 200f, endX: 20f, centerY,
+            DrawPipe(target, intakePipe, startX: 200f, endX: 20f, centerY + 10 - cylRect.Size.Y / 2,
                      T_ambient, T_hot, T_cold, R, NormaliseTemperature, false);
         }
 
@@ -280,7 +306,7 @@ namespace FluidSim.Core
                 double rho = pipe.GetCellDensity(i);
                 double T = p / (rho * R);
 
-                float r = baseRadius * 0.3f * (float)(1.0 + (p - ambPress) / ambPress);
+                float r = baseRadius * 0.2f * (float)(1.0 + (p - ambPress) / ambPress);
                 if (r < 2f) r = 2f;
 
                 float tn = normaliseTemp(T);