Add American V8 preset, carb fuel transport, and adaptive desktop audio

include/FluidSim/Engine.hpp

@@ -31,6 +31,7 @@ private:
 class EngineCylinder : public Component {
 public:
     Ecu* ecu{}; // Optional ideal electronic fuel/ignition controller.
+    bool transported_fuel{}; // Upstream carb meters the fuel species.
     float bore{0.075f}, stroke{0.068f}, rod{0.112f}, compression{11.5f};
     float intake_valve_diameter{0.030f}, exhaust_valve_diameter{0.028f};
     int intake_valve_count{1}, exhaust_valve_count{1};
@@ -60,6 +61,7 @@ public:
 
 protected:
     float energy_factor_{1.0f};
+    float active_fuel_mass_{};
     float rev_limit_timer_{};
     std::mt19937 random_{0xF17D51u};
     std::uniform_real_distribution<float> unit_{0.0f, 1.0f};