Add machine workshop, typed logic, mechanics and sensor-driven ECUs

include/FluidSim/Engine.hpp

@@ -4,6 +4,8 @@
 #include "FluidSim/Constants.hpp"
 #include <array>
 #include <cstddef>
+#include <limits>
+#include <optional>
 #include <random>
 #include <vector>
 
@@ -25,6 +27,8 @@ public:
     float average_power{}, average_torque{};
 
     void add_torque(float torque);
+    float take_torque(); // Consume gas torque when an external shaft integrator owns motion.
+    void record_output(float torque,float power);
     void step(float dt);
 private:
     float external_torque_{};
@@ -51,6 +55,7 @@ public:
     float rev_limit_rpm{7500.0f}, rev_limit_cut_time{0.05f}, rev_limit_hysteresis{200.0f};
     float air_mass{}, exhaust_mass{}, energy{}, volume{}, pressure{101325.0f};
     float fuel_mass{}, burn_fraction{};
+    float fuel_equivalent_mass{}; // passive fuel-origin tracer, unaffected by combustion
     bool combustion_active{}, fuel_injected{}, rev_limit_active{};
     Port intake{}, exhaust{};
 
@@ -84,6 +89,14 @@ protected:
 
 class FourStrokeCylinder final : public EngineCylinder {
 public:
+    struct IgnitionCommand {bool fire{},cut{true};};
+    // Present selects external timing exclusively. A fire pulse is consumed
+    // once; missing subsequent commands cannot recreate internal timed sparks.
+    // Requires physically transported fuel, including carburetor operation.
+    std::optional<IgnitionCommand> ignition_command;
+    // Once per cycle, before ignition consumes fuel. Independent of spark cut.
+    float charge_afr{std::numeric_limits<float>::quiet_NaN()};
+    bool charge_sampled{};
     struct CamPoint { float angle_degrees{}, lift_metres{}; };
     struct ValveDynamics {
         float mass_kg{0.035f};
@@ -106,6 +119,8 @@ public:
     static float cam_lift_at(const CamProfile& profile,float degrees) { return sample_cam(profile,degrees).lift_metres; }
 
 private:
+    float external_burn_angle_{};
+    bool external_charge_ready_{};
     struct ValveState { float lift{},velocity{};bool floating{}; };
     const CamProfile* intake_cam_{};
     const CamProfile* exhaust_cam_{};