86 lines
3.3 KiB
C++
86 lines
3.3 KiB
C++
#pragma once
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#include "FluidSim/Component.hpp"
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#include "FluidSim/Constants.hpp"
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#include <array>
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#include <cstddef>
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#include <random>
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namespace fluidsim::port {
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class Ecu;
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class Crankshaft {
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public:
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float omega{400.0f * 2.0f * pi / 60.0f};
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float angle{}, previous_angle{}, inertia{0.2f};
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float friction_constant{}, friction_viscous{};
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float friction_quadratic{}; // Nm / (rad/s)^2, dissipative windage term
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float load_torque{}, drivetrain_torque{};
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float average_power{}, average_torque{};
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void add_torque(float torque);
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void step(float dt);
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private:
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float external_torque_{};
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std::array<float, 16384> power_buffer_{}, torque_buffer_{};
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std::size_t power_index_{}, power_count_{}, torque_index_{}, torque_count_{};
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float power_sum_{}, torque_sum_{};
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};
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class EngineCylinder : public Component {
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public:
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Ecu* ecu{}; // Optional ideal electronic fuel/ignition controller.
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bool transported_fuel{}; // Upstream carb meters the fuel species.
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float bore{0.075f}, stroke{0.068f}, rod{0.112f}, compression{11.5f};
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float intake_valve_diameter{0.030f}, exhaust_valve_diameter{0.028f};
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int intake_valve_count{1}, exhaust_valve_count{1};
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float intake_valve_lift{0.005f}, exhaust_valve_lift{0.005f};
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float phase{};
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float spark_advance{20.0f}, wiebe_a{5.0f}, wiebe_m{2.0f}, burn_duration{60.0f}, burn_start{5.0f};
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float afr{14.7f}, fuel_lhv{44.0e6f}, energy_variation{0.05f}, misfire_probability{};
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float wall_area{0.02f}, heat_transfer{100.0f}, ambient_temperature{300.0f};
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bool rev_limit_enabled{};
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float rev_limit_rpm{7500.0f}, rev_limit_cut_time{0.05f}, rev_limit_hysteresis{200.0f};
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float air_mass{}, exhaust_mass{}, energy{}, volume{}, pressure{101325.0f};
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float fuel_mass{}, burn_fraction{};
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bool combustion_active{}, fuel_injected{}, rev_limit_active{};
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Port intake{}, exhaust{};
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std::vector<Port*> ports() override { return {&intake, &exhaust}; }
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float swept_volume() const;
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float clearance_volume() const;
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float total_mass() const;
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float temperature() const;
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float air_fraction() const;
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float compute_volume(float theta) const;
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void initialize(const Crankshaft& crank);
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virtual float valve_area(float cycle_degrees, bool inlet) const = 0;
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virtual void pre_step(Crankshaft& crank, float dt, float throttle) = 0;
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void update_state(float dt) override;
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protected:
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float energy_factor_{1.0f};
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float active_fuel_mass_{};
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float rev_limit_timer_{};
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std::mt19937 random_{0xF17D51u};
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std::uniform_real_distribution<float> unit_{0.0f, 1.0f};
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float random_unit();
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static float wrap_degrees(float value, float cycle_degrees = 720.0f);
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static bool crossed_angle(float previous, float current, float event) {
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return current >= previous ? previous < event && current >= event : event > previous || event <= current;
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}
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static bool crossed_window_close(float previous, float current, float open, float close);
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void update_rev_limiter(float rpm, float dt);
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void sync_ports();
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};
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class FourStrokeCylinder final : public EngineCylinder {
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public:
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float intake_open{340.0f}, intake_close{590.0f}, exhaust_open{130.0f}, exhaust_close{390.0f};
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float valve_area(float cycle_degrees, bool inlet) const override;
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void pre_step(Crankshaft& crank, float dt, float throttle) override;
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};
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} // namespace fluidsim::port
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