Energy based changes

Car simulation/Car.cs

@@ -5,10 +5,11 @@ namespace Car_simulation
     public class Car
     {
         public Vector2 Position = new Vector2(0, 0);
-        public Vector2 Velocity = new Vector2(0, 0);
+        public Vector2 Velocity => new Vector2(WheelSystem.CarSpeed, 0); // Now directly from wheels
-        public float Speed => Velocity.Length;
 
-        public float Mass = 1500f; // kg
+        public float Speed => WheelSystem.CarSpeed;
+
+        public float Mass { get; set; } = 1500f; // kg
         public int WheelCount = 4;
         public int DrivenWheels = 2;
 
@@ -20,7 +21,7 @@ namespace Car_simulation
 
         // Aerodynamics
         private const float AirDensity = 1.225f;
-        public float DragCoefficient = 0.1f;
+        public float DragCoefficient = 0.3f;
         public float FrontalArea = 2.2f; // m²
         public float RollingResistanceCoefficient = 0.015f;
 
@@ -36,12 +37,14 @@ namespace Car_simulation
         {
             Engine = new Engine();
             WheelSystem = new WheelSystem();
-            Drivetrain = new Drivetrain(Engine, WheelSystem);
 
-            // Initial setup
+            // Set car mass in wheel system (so it's included in energy calculations)
+            WheelSystem.CarMass = Mass;
             WheelSystem.WheelCount = WheelCount;
             WheelSystem.DrivenWheels = DrivenWheels;
 
+            Drivetrain = new Drivetrain(Engine, WheelSystem);
+
             InitializeAudio();
         }
 
@@ -52,7 +55,6 @@ namespace Car_simulation
                 _engineSound = new EngineSound();
                 _engineSound.SetEngineState(Engine.IdleRPM, 0f);
                 _engineSound.StartSound();
-
             }
             catch (Exception ex)
             {
@@ -64,27 +66,30 @@ namespace Car_simulation
         public void Update(float deltaTime)
         {
             Engine.Throttle = ThrottleInput;
-            Drivetrain.ClutchEngagement = 1f - ClutchInput; // Convert: 0 input = 1 engagement
+            Drivetrain.ClutchEngagement = 1f - ClutchInput;
 
             if (ForceClutch)
                 Drivetrain.ClutchEngagement = 0f;
 
-            float resistanceTorque = CalculateResistanceTorque();
+            // Update engine
-            WheelSystem.ResistanceTorque = resistanceTorque;
+            Engine.Update(deltaTime);
 
+            // Update drivetrain (transfers energy between engine and wheels+car)
             Drivetrain.Update(deltaTime);
+
+            // Calculate and apply resistance
+            float resistanceForce = CalculateTotalResistanceForce();
+            WheelSystem.ResistanceTorque = resistanceForce * WheelSystem.Radius;
             WheelSystem.ApplyResistance(deltaTime);
 
-            float engineLoad = Drivetrain.CalculateEngineLoad(deltaTime);
+            // Apply braking
-            Engine.Update(deltaTime, engineLoad);
-
-            UpdateVehicleMotion(deltaTime);
             ApplyBraking(deltaTime);
 
+            // Update position based on velocity (which comes from WheelSystem)
+            Position += Velocity * deltaTime;
+
             if (_audioEnabled)
-            {
                 UpdateAudio();
-            }
         }
 
         private void UpdateAudio()
@@ -100,72 +105,11 @@ namespace Car_simulation
             }
         }
 
-        private void UpdateVehicleMotion(float deltaTime)
-        {
-            // Calculate net force
-            float tractiveForce = CalculateTractiveForce();
-            float resistanceForce = CalculateTotalResistanceForce();
-            float netForce = tractiveForce - resistanceForce;
-
-            // Calculate acceleration: a = F / m
-            float acceleration = netForce / Mass;
-
-            // Update velocity: v = v₀ + a·Δt
-            if (Velocity.Length > 0)
-            {
-                Vector2 direction = Velocity.Normalized();
-                float newSpeed = Velocity.Length + acceleration * deltaTime;
-                newSpeed = Math.Max(newSpeed, 0); // Don't go backwards without reverse gear
-                Velocity = direction * newSpeed;
-            }
-            else
-            {
-                // Starting from standstill
-                Velocity = new Vector2(acceleration * deltaTime, 0);
-            }
-
-            Position += Velocity * deltaTime;
-
-            // Sync wheel speed with actual vehicle speed (with slip allowance)
-            float currentWheelSpeed = Velocity.Length;
-            WheelSystem.SetSpeed(currentWheelSpeed);
-        }
-
-        private float CalculateTractiveForce()
-        {
-            // 1. Get the torque available at the wheels
-            float wheelTorque = Drivetrain.ClutchTorque * Drivetrain.Efficiency;
-
-            // 2. Convert torque to theoretical force: F = τ / r
-            float theoreticalForce = wheelTorque / WheelSystem.Radius;
-
-            // 3. Account for weight distribution and driven wheels
-            // Normal load on driven wheels = (DrivenWheels / WheelCount) * Weight
-            float drivenWheelNormalLoad = (DrivenWheels / (float)WheelCount) * Mass * 9.81f;
-
-            // 4. Calculate maximum tractive force based on friction (tire grip)
-            float frictionCoefficient = 1.2f; // Typical tire on dry asphalt
-            float maxTractiveForce = drivenWheelNormalLoad * frictionCoefficient;
-
-            // 5. Limit the force by what the tires can actually grip
-            // Also handle direction (forward/reverse)
-            if (theoreticalForce > 0)
-            {
-                return Math.Min(theoreticalForce, maxTractiveForce);
-            }
-            else
-            {
-                // For reverse or engine braking
-                return Math.Max(theoreticalForce, -maxTractiveForce);
-            }
-        }
-
         private void ApplyBraking(float deltaTime)
         {
             if (BrakeInput <= 0) return;
 
-            float brakeTorque = BrakeInput * 500f; // 500 Nm max brake torque
+            float brakeTorque = BrakeInput * 3000f;
-
             WheelSystem.ApplyTorque(-brakeTorque, deltaTime);
         }
 
@@ -178,40 +122,34 @@ namespace Car_simulation
 
         private float CalculateDragForce()
         {
-            // F_drag = 0.5 * ρ * Cd * A * v²
             float speed = Speed;
             return 0.5f * AirDensity * DragCoefficient * FrontalArea * speed * speed;
         }
 
         private float CalculateRollingResistanceForce()
         {
-            // F_rolling = C_r * m * g
             return RollingResistanceCoefficient * Mass * 9.81f;
         }
 
-        // Convert resistance force to wheel torque
-        public float CalculateResistanceTorque()
-        {
-            float totalForce = CalculateTotalResistanceForce();
-            return totalForce * WheelSystem.Radius;
-        }
-
         public void DisplayUpdate()
         {
             Console.SetCursorPosition(0, 0);
             Console.WriteLine($"Engine Energy: {Engine.FlywheelEnergy,7:F0} J");
             Console.WriteLine($"Engine Torque: {Engine.GetTorqueOutput(),7:F0} Nm");
             Console.WriteLine($"Engine RPM: {Engine.RPM,7:F0}");
-            Console.WriteLine($"Wheel Energy: {WheelSystem.WheelEnergy,7:F0} J");
+            Console.WriteLine($"Total Energy: {WheelSystem.TotalEnergy,7:F0} J");
+            Console.WriteLine($"  (Wheel Rot: {WheelSystem.GetRotationalEnergy(),7:F0} J)");
+            Console.WriteLine($"  (Car Trans: {WheelSystem.GetTranslationalEnergy(),7:F0} J)");
             Console.WriteLine($"Wheel RPM: {WheelSystem.RPM,7:F0}");
             Console.WriteLine($"Vehicle: {Speed * 3.6f,7:F1} km/h");
             Console.WriteLine($"Throttle: {Engine.GetActualThrottle() * 100,6:F1}%");
             Console.WriteLine($"Power: {Engine.CurrentPower / 1000,6:F1} kW");
             Console.WriteLine($"Transmitted: {Drivetrain.TransmittedPower / 1000,6:F1} kW");
             Console.WriteLine($"Brake: {BrakeInput * 100,6:F1}%");
-            Console.WriteLine($"Clutch: {ClutchInput * 100,6:F1}% disengaged");
             Console.WriteLine($"Speed Diff: {Drivetrain.GetSpeedDifferenceRPM(),6:F0} RPM");
+            Console.WriteLine($"Clutch: {ClutchInput * 100,6:F1}% disengaged");
             Console.WriteLine($"Clutch T: {Drivetrain.ClutchTorque,6:F0} Nm");
+            Console.WriteLine($"Clutch Slip: {Drivetrain.GetClutchSlipPercent(),6:F1}%");
             Console.WriteLine($"Resistance: {CalculateTotalResistanceForce(),6:F1} N");
             Console.WriteLine($"Drag: {CalculateDragForce(),6:F1} N");
             Console.WriteLine($"Rolling: {CalculateRollingResistanceForce(),6:F1} N");

Car simulation/Drivetrain.cs

@@ -9,188 +9,139 @@
         private int currentGear = 1;
         public float[] GearRatios { get; set; } =
         {
-            3.8f,   // 1st - Lower for better launch
+            3.8f,   // 1st
             2.5f,   // 2nd
             1.8f,   // 3rd
             1.3f,   // 4th
-            1.0f,   // 5th - Direct drive
+            1.0f,   // 5th
-            0.8f,   // 6th - Overdrive
+            0.8f,   // 6th
-            0.65f   // 7th - Double overdrive (optional)
+            0.65f   // 7th
         };
-        public float FinalDriveRatio { get; set; } = 5.0f;
+        public float FinalDriveRatio { get; set; } = 4.0f;
         public float Efficiency { get; set; } = 0.95f;
         public float ClutchEngagement { get; set; } = 0f; // 0 = disengaged, 1 = fully engaged
 
-        // Calculated
-        public float GearRatio => GetCurrentGearRatio();
-        public float TotalRatio => GearRatio * FinalDriveRatio;
-
         // Clutch properties
-        public float ClutchStiffness { get; set; } = 500f; // Nm/(rad/s) - how strongly clutch pulls speeds together
+        public float MaxClutchTorque { get; set; } = 450f;
-        public float MaxClutchTorque { get; set; } = 4500f; // Maximum torque clutch can transmit
+        public float ClutchStiffness { get; set; } = 20f; // Softer spring
 
         // State
-        public float SpeedDifference { get; private set; } // rad/s
         public float ClutchTorque { get; private set; }
         public float TransmittedPower { get; private set; }
-
+        public float ClutchSlipRatio { get; private set; }
-        private float previousWheelOmega = 0f;
 
         public Drivetrain(Engine engine, WheelSystem wheelSystem)
         {
             Engine = engine;
             WheelSystem = wheelSystem;
-            previousWheelOmega = wheelSystem.AngularVelocity;
         }
 
-        public void GearUp()
+        public void Update(float deltaTime)
-        {
-            if (currentGear < GearRatios.Length)
-            currentGear++;
-        }
-
-        public void GearDown()
-        {
-            if (currentGear > 1)
-            currentGear--;
-        }
-
-        private float GetCurrentGearRatio()
-        {
-            if (currentGear == 0) return 0f; // Neutral
-            if (currentGear == -1) return -3.5f; // Reverse (example ratio)
-            if (currentGear > 0 && currentGear <= GearRatios.Length)
-                return GearRatios[currentGear - 1];
-            return 0f; // Invalid gear
-        }
-
-        public float CalculateSpeedDifference()
-        {
-            if (TotalRatio == 0) return 0f;
-
-            float engineOmega = Engine.AngularVelocity;
-            float wheelOmega = WheelSystem.AngularVelocity;
-            float expectedWheelOmega = engineOmega / TotalRatio;
-
-            SpeedDifference = wheelOmega - expectedWheelOmega;
-            return SpeedDifference;
-        }
-
-        public float CalculateClutchTorque()
-        {
-            if (ClutchEngagement <= 0.01f)
-            {
-                ClutchTorque = 0;
-                return 0f;
-            }
-
-            CalculateSpeedDifference();
-
-            float torque = -SpeedDifference * ClutchStiffness * ClutchEngagement;
-            torque = Math.Clamp(torque, -MaxClutchTorque, MaxClutchTorque);
-
-            float actualThrottle = Engine.GetActualThrottle();
-            float availableEngineTorque = Engine.GetTorqueOutput();
-
-            float maxTorqueAtClutch = maxEngineTorque * TotalRatio * Efficiency;
-
-            torque = maxTorqueAtClutch;
-
-
-            ClutchTorque = torque;
-            return torque;
-        }
-
-        public void ApplyDrivetrainWork(float deltaTime)
         {
             if (ClutchEngagement <= 0.01f || TotalRatio == 0)
             {
                 ClutchTorque = 0;
                 TransmittedPower = 0;
+                ClutchSlipRatio = 1f;
                 return;
             }
 
-            CalculateSpeedDifference();
+            // Calculate expected vs actual wheel speeds
-            float clutchTorque = CalculateClutchTorque();
+            float expectedWheelOmega = Engine.AngularVelocity / TotalRatio;
+            float actualWheelOmega = WheelSystem.AngularVelocity;
+            float omegaDifference = actualWheelOmega - expectedWheelOmega;
 
-            bool engineDrivingWheels = clutchTorque > 0;
+            // Calculate max torque clutch can transmit
-            bool wheelsDrivingEngine = clutchTorque < 0;
+            float maxClutchTorque = MaxClutchTorque * ClutchEngagement;
 
-            if (engineDrivingWheels)
+            // Simple spring model: torque tries to sync speeds
+            float desiredTorque = -omegaDifference * ClutchStiffness;
+
+            // Clamp to clutch capacity
+            desiredTorque = Math.Clamp(desiredTorque, -maxClutchTorque, maxClutchTorque);
+
+            // Also limit by engine capability when accelerating
+            if (desiredTorque > 0)
             {
-                // Engine -> Wheels (normal driving)
+                float engineTorque = Engine.GetTorqueOutput() * Engine.GetActualThrottle();
-                ApplyEngineToWheels(clutchTorque, deltaTime);
+                float maxEngineTorqueAtWheels = engineTorque * TotalRatio * Efficiency;
-            }
+                desiredTorque = Math.Min(desiredTorque, maxEngineTorqueAtWheels);
-            else if (wheelsDrivingEngine)
-            {
-                // Wheels -> Engine (engine braking)
-                ApplyWheelsToEngine(clutchTorque, deltaTime);
             }
 
-            TransmittedPower = clutchTorque * SpeedDifference;
+            ClutchTorque = desiredTorque;
+
+            // Calculate energy transfer based on torque
+            float energyTransferred = 0f;
+
+            if (omegaDifference > 0.01f) // Wheels → Engine (engine braking)
+            {
+                // Power = torque × angular velocity (at slower side - engine)
+                float power = ClutchTorque * (Engine.AngularVelocity);
+                energyTransferred = power * deltaTime;
+
+                // Wheels lose energy, engine gains (minus efficiency losses)
+                float wheelEnergyLoss = Math.Abs(energyTransferred);
+                float engineEnergyGain = wheelEnergyLoss * Efficiency;
+
+                WheelSystem.TotalEnergy -= wheelEnergyLoss;
+                Engine.FlywheelEnergy += engineEnergyGain;
+            }
+            else if (omegaDifference < -0.01f) // Engine → Wheels (acceleration)
+            {
+                // Power = torque × angular velocity (at faster side - engine)
+                float power = -ClutchTorque * Engine.AngularVelocity; // Negative torque, positive power
+                energyTransferred = power * deltaTime;
+
+                // Engine loses energy, wheels gain
+                float engineEnergyLoss = Math.Abs(energyTransferred);
+                float wheelEnergyGain = engineEnergyLoss * Efficiency;
+
+                Engine.FlywheelEnergy -= engineEnergyLoss;
+                WheelSystem.TotalEnergy += wheelEnergyGain;
+            }
+            else
+            {
+                // Nearly synchronized
+                energyTransferred = 0;
+            }
+
+            // Calculate transmitted power
+            TransmittedPower = energyTransferred / deltaTime;
+
+            // Calculate clutch slip CORRECTLY:
+            // Slip = 0 when torque < max torque (clutch can handle it)
+            // Slip = 1 when torque = max torque (clutch is slipping)
+            if (maxClutchTorque > 0)
+            {
+                float torqueRatio = Math.Abs(ClutchTorque) / maxClutchTorque;
+                // If we're transmitting max torque, clutch is slipping
+                // If we're transmitting less, clutch is gripping
+                ClutchSlipRatio = torqueRatio; // 0 = no slip, 1 = full slip
+            }
+            else
+            {
+                ClutchSlipRatio = 1f;
+            }
         }
 
-        private void ApplyEngineToWheels(float clutchTorque, float deltaTime)
+        // Other methods...
+        public float GearRatio => GetCurrentGearRatio();
+        public float TotalRatio => GearRatio * FinalDriveRatio;
+
+        private float GetCurrentGearRatio()
         {
-            // Existing logic for engine driving wheels
+            if (currentGear == 0) return 0f;
-            float netWheelTorque = clutchTorque * Efficiency - WheelSystem.ResistanceTorque;
+            if (currentGear == -1) return -3.5f;
-            float netEngineTorque = -clutchTorque / TotalRatio;
+            if (currentGear > 0 && currentGear <= GearRatios.Length)
-
+                return GearRatios[currentGear - 1];
-            // Apply to both
+            return 0f;
-            Engine.ApplyTorque(netEngineTorque, deltaTime);
-            WheelSystem.ApplyTorque(netWheelTorque, deltaTime);
         }
 
-        private void ApplyWheelsToEngine(float clutchTorque, float deltaTime)
-        {
-            // Wheels driving engine (engine braking)
-            // Negative clutchTorque means wheels are trying to spin engine faster
-
-            float wheelTorque = clutchTorque; // Negative value
-            float engineTorque = -clutchTorque / TotalRatio; // Positive resistance
-
-            // Apply resistance to wheels
-            WheelSystem.ApplyTorque(wheelTorque, deltaTime);
-
-            Engine.ApplyTorque(-engineTorque, deltaTime); // Negative = slowing
-        }
-
-        public float GetEquivalentInertiaAtEngine()
-        {
-            float wheelInertia = WheelSystem.GetTotalInertia();
-            return Engine.MomentOfInertia + (wheelInertia * TotalRatio * TotalRatio);
-        }
-
-        public float CalculateEngineLoad(float deltaTime)
-        {
-            if (ClutchEngagement <= 0.01f) return 0f;
-
-            float wheelResistanceTorque = WheelSystem.ResistanceTorque;
-            float engineLoadTorque = wheelResistanceTorque / (TotalRatio * Efficiency);
-
-            float inertiaLoad = CalculateInertiaLoad(deltaTime);
-
-            return engineLoadTorque + inertiaLoad;
-        }
-
-        private float CalculateInertiaLoad(float deltaTime)
-        {
-            float wheelAlpha = (WheelSystem.AngularVelocity - previousWheelOmega) / deltaTime;
-            previousWheelOmega = WheelSystem.AngularVelocity;
-
-            float inertiaTorque = wheelAlpha * WheelSystem.GetTotalInertia();
-            return inertiaTorque / (TotalRatio * TotalRatio * Efficiency);
-        }
-
-        public void Update(float deltaTime)
-        {
-            ApplyDrivetrainWork(deltaTime);
-        }
-
-        // Helper methods
         public float GetSpeedDifferenceRPM()
         {
-            return SpeedDifference * PhysicsUtil.RAD_PER_SEC_TO_RPM;
+            float expectedWheelOmega = Engine.AngularVelocity / TotalRatio;
+            float actualWheelOmega = WheelSystem.AngularVelocity;
+            return (actualWheelOmega - expectedWheelOmega) * PhysicsUtil.RAD_PER_SEC_TO_RPM;
         }
 
         public string GetCurrentGearName()
@@ -202,5 +153,13 @@
                 _ => currentGear.ToString()
             };
         }
+
+        public float GetClutchSlipPercent()
+        {
+            return ClutchSlipRatio * 100f;
+        }
+
+        public void GearUp() { if (currentGear < GearRatios.Length) currentGear++; }
+        public void GearDown() { if (currentGear > 1) currentGear--; }
     }
 }

Car simulation/Engine.cs

@@ -3,7 +3,7 @@
     public class Engine
     {
         // Energy state
-        public float FlywheelEnergy { get; set; } // Joules
+        public float FlywheelEnergy { get; set; }
 
         // Values
         public float RPM => GetRPM();
@@ -11,40 +11,35 @@
         public float CurrentPower { get; private set; }
 
         // Physical properties
-        public float MomentOfInertia { get; set; } = 0.25f; // kg·m²
+        public float MomentOfInertia { get; set; } = 0.25f;
         public float IdleRPM { get; set; } = 800f;
         public float StallSpeed { get; set; } = 200f;
         public float Throttle { get; set; } = 0f;
         public bool IsRunning => RPM > StallSpeed;
 
-        // Torque characteristics
+        // Torque curve
         public Dictionary<float, float> TorqueCurve { get; set; } = new()
         {
-            // RPM - Torque Nm
             { 0f, 0f },
-            { 800f, 150f },   // Idle
+            { 800f, 150f },
-            { 2000f, 200f },  // Peak torque
+            { 2000f, 250 },
             { 4500f, 250f },
-            { 7200f, 250f },
+            { 6800f, 200f },
-            { 9200f, 250f },
+            { 7200f, 150 },
-            { 10000f, 200f },
+            { 7500f, 0f },
-            { 11000f, 0f }
         };
 
         public Engine()
         {
-            // Start with idle energy
             FlywheelEnergy = GetEnergyFromRPM(IdleRPM);
         }
 
-        // Calculations
+        public float CalculateFrictionLoss(float deltaTime)
-
-        public float CalculateFrictionEnergy(float deltaTime)
         {
-            // Real friction torque data for 2.0L engine (Nm)
             float frictionTorque;
 
-            if (RPM < 500) frictionTorque = 15f;  // Static/breakaway
+            // Realistic friction based on RPM
+            if (RPM < 500) frictionTorque = 15f;
             else if (RPM < 1000) frictionTorque = 14f;
             else if (RPM < 2000) frictionTorque = 16f;
             else if (RPM < 3000) frictionTorque = 18f;
@@ -58,29 +53,28 @@
             return frictionPower * deltaTime;
         }
 
-        private float CalculateCombustionEnergy(float deltaTime)
+        public float CalculateCombustionPower(float deltaTime)
         {
             float torque = GetTorqueOutput() * GetActualThrottle();
             return torque * AngularVelocity * deltaTime;
         }
 
-        private float CalculateLoadEnergy(float deltaTime, float loadTorque)
-        {
-            return loadTorque * AngularVelocity * deltaTime;
-        }
-
-        // Get
-
         public float GetActualThrottle()
         {
-            float idleThrottle = Math.Max((IdleRPM - RPM) / 10, 0);
+            // Idle control: maintain idle speed when throttle is low
-            return Math.Clamp(Throttle + idleThrottle, 0, 1);
+            if (RPM < IdleRPM && Throttle < 0.1f)
+            {
+                float idleThrottle = (IdleRPM - RPM) / 200f;
+                return Math.Clamp(idleThrottle, 0.1f, 0.3f);
+            }
+
+            return Throttle;
         }
 
         public float GetOmega()
         {
             if (FlywheelEnergy <= 0) return 0;
-                return MathF.Sqrt(2f * FlywheelEnergy / MomentOfInertia);
+            return MathF.Sqrt(2f * FlywheelEnergy / MomentOfInertia);
         }
 
         public float GetRPM()
@@ -88,15 +82,12 @@
             return GetOmega() * PhysicsUtil.RAD_PER_SEC_TO_RPM;
         }
 
-        // Set
-
         public float GetEnergyFromRPM(float rpm)
         {
             float omega = rpm * PhysicsUtil.RPM_TO_RAD_PER_SEC;
             return 0.5f * MomentOfInertia * omega * omega;
         }
 
-        // torque curve
         public float GetTorqueOutput()
         {
             if (RPM <= 0) return 0;
@@ -118,25 +109,28 @@
             return 0f;
         }
 
-        public void ApplyTorque(float torque, float deltaTime)
+        public void Update(float deltaTime)
         {
-            if (torque == 0) return;
+            // Combustion adds energy (if throttle > 0)
+            float combustionEnergy = CalculateCombustionPower(deltaTime);
 
-            float work = torque * AngularVelocity * deltaTime;
+            // Friction always removes energy
+            float frictionLoss = CalculateFrictionLoss(deltaTime);
 
-            FlywheelEnergy += work;
+            // Net energy change from combustion and friction ONLY
-            FlywheelEnergy = Math.Max(FlywheelEnergy, 0);
+            // Note: Drivetrain energy transfer happens separately in Drivetrain.Update()
-        }
+            float netEnergy = combustionEnergy - frictionLoss;
-
-        public void Update(float deltaTime, float loadTorque)
-        {
-            float combustionEnergy = CalculateCombustionEnergy(deltaTime);
-            float frictionEnergy = CalculateFrictionEnergy(deltaTime);
-            float loadEnergy = CalculateLoadEnergy(deltaTime, loadTorque);
-
-            float netEnergy = combustionEnergy - frictionEnergy - loadEnergy;
             CurrentPower = netEnergy / deltaTime;
+
             FlywheelEnergy += netEnergy;
+
+            // Stall protection - keep engine running if it has throttle
+            float stallEnergy = GetEnergyFromRPM(StallSpeed);
+            if (FlywheelEnergy < stallEnergy && Throttle > 0.1f)
+            {
+                FlywheelEnergy = stallEnergy * 1.2f;
+            }
+
             FlywheelEnergy = Math.Max(FlywheelEnergy, 0);
         }
     }

Car simulation/Program.cs

@@ -138,21 +138,21 @@ internal class Program
         // brake
         if (IsKeyDown(Keyboard.Key.B))
         {
-            car.BrakeInput = Math.Min(car.BrakeInput + 0.5f * deltaTime, 1.0f);
+            car.BrakeInput = Math.Min(car.BrakeInput + 1f * deltaTime, 1.0f);
         }
         else
         {
-            car.BrakeInput = Math.Max(car.BrakeInput - 1f * deltaTime, 0f);
+            car.BrakeInput = Math.Max(car.BrakeInput - 4f * deltaTime, 0f);
         }
 
         // clutch
         if (IsKeyDown(Keyboard.Key.Up))
         {
-            car.ClutchInput = Math.Min(car.ClutchInput + 1f * deltaTime, 1.0f);
+            car.ClutchInput = Math.Min(car.ClutchInput + 0.1f * deltaTime, 1.0f);
         }
         else if (IsKeyDown(Keyboard.Key.Down))
         {
-            car.ClutchInput = Math.Max(car.ClutchInput - 1f * deltaTime, 0f);
+            car.ClutchInput = Math.Max(car.ClutchInput - 0.1f * deltaTime, 0f);
         }
 
         // clutch

Car simulation/WheelSystem.cs

@@ -4,27 +4,43 @@
     {
         // Physical properties
         public float Radius { get; set; } = 0.3f; // meters
-        public float Inertia { get; set; } = 2.0f; // kg·m² per wheel
+        public float WheelInertia { get; set; } = 2.0f; // kg·m² per wheel
+        public float CarMass { get; set; } = 1500f; // kg - Car mass integrated into wheel system
+
         public int WheelCount { get; set; } = 4;
         public int DrivenWheels { get; set; } = 2; // 2WD
 
         // State
-        public float WheelEnergy { get; set; } = 0f; // Joules
+        public float TotalEnergy { get; set; } = 0f; // Joules (rotational + translational)
         public float AngularVelocity => GetOmega();
         public float RPM => GetRPM();
-        public float Speed => GetSpeed();
+        public float CarSpeed => GetCarSpeed(); // Now returns actual car speed
+
         public float ResistanceTorque { get; set; } = 0f;
 
         // Calculations
+        public float GetTotalRotationalInertia()
+        {
+            return WheelInertia * WheelCount;
+        }
+
+        public float GetEquivalentCarInertia()
+        {
+            // Convert car mass to equivalent rotational inertia at wheels
+            // I = m * r² (from v = ω * r, so KE_translational = 0.5 * m * v² = 0.5 * m * (ωr)² = 0.5 * m * r² * ω²)
+            return CarMass * Radius * Radius;
+        }
+
         public float GetTotalInertia()
         {
-            return Inertia * WheelCount;
+            // Total inertia = rotational inertia of wheels + equivalent inertia of car mass
+            return GetTotalRotationalInertia() + GetEquivalentCarInertia();
         }
 
         public float GetOmega()
         {
-            if (WheelEnergy <= 0 || GetTotalInertia() <= 0) return 0f;
+            if (TotalEnergy <= 0 || GetTotalInertia() <= 0) return 0f;
-            return MathF.Sqrt(2f * WheelEnergy / GetTotalInertia());
+            return MathF.Sqrt(2f * TotalEnergy / GetTotalInertia());
         }
 
         public float GetRPM()
@@ -32,27 +48,46 @@
             return AngularVelocity * PhysicsUtil.RAD_PER_SEC_TO_RPM;
         }
 
-        public float GetSpeed()
+        public float GetCarSpeed()
         {
+            // v = ω * r (no slip assumed for base calculation)
             return AngularVelocity * Radius;
         }
 
+        public float GetRotationalEnergy()
+        {
+            // Just the energy from wheel rotation
+            float omega = GetOmega();
+            return 0.5f * GetTotalRotationalInertia() * omega * omega;
+        }
+
+        public float GetTranslationalEnergy()
+        {
+            // Just the energy from car motion
+            float speed = GetCarSpeed();
+            return 0.5f * CarMass * speed * speed;
+        }
+
         public float GetEnergyFromSpeed(float speed)
         {
+            // Calculate total energy for given car speed
+            // Total energy = rotational energy of wheels + translational energy of car
             float omega = speed / Radius;
-            return 0.5f * GetTotalInertia() * omega * omega;
+            float rotationalEnergy = 0.5f * GetTotalRotationalInertia() * omega * omega;
+            float translationalEnergy = 0.5f * CarMass * speed * speed;
+            return rotationalEnergy + translationalEnergy;
         }
 
         public void SetSpeed(float speed)
         {
-            WheelEnergy = GetEnergyFromSpeed(speed);
+            TotalEnergy = GetEnergyFromSpeed(speed);
         }
 
-        // Apply work to the wheels
+        // Apply work to the entire system (wheels + car)
         public void ApplyWork(float work)
         {
-            WheelEnergy += work;
+            TotalEnergy += work;
-            WheelEnergy = Math.Max(WheelEnergy, 0);
+            TotalEnergy = Math.Max(TotalEnergy, 0);
         }
 
         public void ApplyTorque(float torque, float deltaTime)
@@ -70,8 +105,7 @@
 
             if (MathF.Abs(omega) < 0.1f)
             {
-                // Check if we have enough torque to overcome static friction
+                // Static friction - return without applying resistance to allow startup
-                // For now, just return without applying resistance to allow startup
                 return;
             }
 
@@ -86,7 +120,7 @@
             }
 
             float energyNew = 0.5f * GetTotalInertia() * omegaNew * omegaNew;
-            WheelEnergy = Math.Max(energyNew, 0);
+            TotalEnergy = Math.Max(energyNew, 0);
         }
     }
 }