32e9505eed
Replace include <iostream> with istream, ostream and/or iosfwd as appropriate. Remove using namespace std and using std::foo from header files.
240 lines
9.6 KiB
C++
240 lines
9.6 KiB
C++
// IO360.hxx - a piston engine model currently for the IO360 engine fitted to the C172
|
|
// but with the potential to model other naturally aspirated piston engines
|
|
// given appropriate config input.
|
|
//
|
|
// Written by David Luff, started 2000.
|
|
// Based on code by Phil Schubert, started 1999.
|
|
//
|
|
// This program is free software; you can redistribute it and/or
|
|
// modify it under the terms of the GNU General Public License as
|
|
// published by the Free Software Foundation; either version 2 of the
|
|
// License, or (at your option) any later version.
|
|
//
|
|
// This program is distributed in the hope that it will be useful, but
|
|
// WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
// General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU General Public License
|
|
// along with this program; if not, write to the Free Software
|
|
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
|
|
|
|
|
#ifndef _IO360_HXX_
|
|
#define _IO360_HXX_
|
|
|
|
#include <simgear/compiler.h>
|
|
|
|
#include <math.h>
|
|
|
|
class FGNewEngine {
|
|
|
|
private:
|
|
|
|
// These constants should probably be moved eventually
|
|
float CONVERT_CUBIC_INCHES_TO_METERS_CUBED;
|
|
float CONVERT_HP_TO_WATTS;
|
|
|
|
// Properties of working fluids
|
|
float Cp_air; // J/KgK
|
|
float Cp_fuel; // J/KgK
|
|
float calorific_value_fuel; // W/Kg
|
|
float rho_fuel; // kg/m^3
|
|
float rho_air; // kg/m^3
|
|
|
|
// environment inputs
|
|
float p_amb_sea_level; // Sea level ambient pressure in Pascals
|
|
float p_amb; // Ambient pressure at current altitude in Pascals
|
|
float T_amb; // ditto deg Kelvin
|
|
|
|
// Control inputs
|
|
float Throttle_Lever_Pos; // 0 = Closed, 100 = Fully Open
|
|
float Propeller_Lever_Pos; // 0 = Full Course 100 = Full Fine
|
|
float Mixture_Lever_Pos; // 0 = Idle Cut Off 100 = Full Rich
|
|
int mag_pos; // 0=off, 1=left, 2=right, 3=both.
|
|
bool starter;
|
|
|
|
//misc
|
|
float IAS;
|
|
double time_step;
|
|
|
|
// Engine Specific Variables that should be read in from a config file
|
|
float MaxHP; // Horsepower
|
|
float displacement; // Cubic inches
|
|
float displacement_SI; //m^3 (derived from above rather than read in)
|
|
float engine_inertia; //kg.m^2
|
|
float prop_inertia; //kg.m^2
|
|
float Max_Fuel_Flow; // Units??? Do we need this variable any more??
|
|
|
|
// Engine specific variables that maybe should be read in from config but are pretty generic and won't vary much for a naturally aspirated piston engine.
|
|
float Max_Manifold_Pressure; // inches Hg - typical manifold pressure at full throttle and typical max rpm
|
|
float Min_Manifold_Pressure; // inches Hg - typical manifold pressure at idle (closed throttle)
|
|
float Max_RPM; // rpm - this is really a bit of a hack and could be make redundant if the prop model works properly and takes tips at speed of sound into account.
|
|
float Min_RPM; // rpm - possibly redundant ???
|
|
float Mag_Derate_Percent; // Percentage reduction in power when mags are switched from 'both' to either 'L' or 'R'
|
|
float Gear_Ratio; // Gearing between engine and propellor
|
|
float n_R; // Number of cycles per power stroke - 2 for a 4 stroke engine.
|
|
|
|
// Engine Variables not read in from config file
|
|
float RPM; // rpm
|
|
float Percentage_Power; // Power output as percentage of maximum power output
|
|
float Manifold_Pressure; // Inches Hg
|
|
float Fuel_Flow_gals_hr; // USgals/hour
|
|
float Torque_lbft; // lb-ft
|
|
float Torque_SI; // Nm
|
|
float CHT; // Cylinder head temperature deg K
|
|
float CHT_degF; // Ditto in deg Fahrenheit
|
|
float Mixture;
|
|
float Oil_Pressure; // PSI
|
|
float Oil_Temp; // Deg C
|
|
float current_oil_temp; // deg K
|
|
/**** one of these is superfluous !!!!***/
|
|
float HP; // Current power output in HP
|
|
float Power_SI; // Current power output in Watts
|
|
float RPS;
|
|
float angular_velocity_SI; // rad/s
|
|
float Torque_FMEP; // The component of Engine torque due to FMEP (Nm)
|
|
float Torque_Imbalance; // difference between engine and prop torque
|
|
float EGT; // Exhaust gas temperature deg K
|
|
float EGT_degF; // Exhaust gas temperature deg Fahrenheit
|
|
float volumetric_efficiency;
|
|
float combustion_efficiency;
|
|
float equivalence_ratio; // ratio of stoichiometric AFR over actual AFR
|
|
float thi_sea_level; // the equivalence ratio we would be running at assuming sea level air denisity in the manifold
|
|
float v_dot_air; // volume flow rate of air into engine - m^3/s
|
|
float m_dot_air; // mass flow rate of air into engine - kg/s
|
|
float m_dot_fuel; // mass flow rate of fuel into engine - kg/s
|
|
float swept_volume; // total engine swept volume - m^3
|
|
/********* swept volume or the geometry used to calculate it should be in the config read section surely ??? ******/
|
|
float True_Manifold_Pressure; //in Hg - actual manifold gauge pressure
|
|
float rho_air_manifold; // denisty of air in the manifold - kg/m^3
|
|
float R_air; // Gas constant of air (287) UNITS???
|
|
float delta_T_exhaust; // Temperature change of exhaust this time step - degK
|
|
float heat_capacity_exhaust; // exhaust gas specific heat capacity - J/kgK
|
|
float enthalpy_exhaust; // Enthalpy at current exhaust gas conditions - UNITS???
|
|
float Percentage_of_best_power_mixture_power; // Current power as a percentage of what power we would have at the same conditions but at best power mixture
|
|
float abstract_mixture; //temporary hack
|
|
float angular_acceleration; //rad/s^2
|
|
float FMEP; //Friction Mean Effective Pressure (Pa)
|
|
|
|
// Various bits of housekeeping describing the engines state.
|
|
bool running; // flag to indicate the engine is running self sustaining
|
|
bool cranking; // flag to indicate the engine is being cranked
|
|
int crank_counter; // Number of iterations that the engine has been cranked non-stop
|
|
bool spark; // flag to indicate a spark is available
|
|
bool fuel; // flag to indicate fuel is available
|
|
|
|
// Propellor Variables
|
|
float FGProp1_RPS; // rps
|
|
float prop_torque; // Nm
|
|
float prop_thrust; // Newtons
|
|
double prop_diameter; // meters
|
|
double blade_angle; // degrees
|
|
|
|
|
|
// MEMBER FUNCTIONS
|
|
|
|
// Calculate Engine RPM based on Propellor Lever Position
|
|
float Calc_Engine_RPM(float Position);
|
|
|
|
// Calculate Manifold Pressure based on throttle lever position
|
|
// Note that this is simplistic and needs altering to include engine speed effects
|
|
float Calc_Manifold_Pressure( float LeverPosn, float MaxMan, float MinMan);
|
|
|
|
// Calculate combustion efficiency based on equivalence ratio
|
|
float Lookup_Combustion_Efficiency(float thi_actual);
|
|
|
|
// Calculate percentage of best power mixture power based on equivalence ratio
|
|
float Power_Mixture_Correlation(float thi_actual);
|
|
|
|
// Calculate exhaust gas temperature change
|
|
float Calculate_Delta_T_Exhaust(void);
|
|
|
|
// Calculate cylinder head temperature
|
|
void Calc_CHT(void);
|
|
|
|
// Calculate exhaust gas temperature
|
|
void Calc_EGT(void);
|
|
|
|
// Calculate fuel flow in gals/hr
|
|
void Calc_Fuel_Flow_Gals_Hr(void);
|
|
|
|
// Calculate current percentage power
|
|
void Calc_Percentage_Power(bool mag_left, bool mag_right);
|
|
|
|
// Calculate Oil Temperature
|
|
float Calc_Oil_Temp (float oil_temp);
|
|
|
|
// Calculate Oil Pressure
|
|
float Calc_Oil_Press (float Oil_Temp, float Engine_RPM);
|
|
|
|
// Propeller calculations.
|
|
void Do_Prop_Calcs(void);
|
|
|
|
public:
|
|
|
|
// ofstream outfile;
|
|
|
|
//constructor
|
|
FGNewEngine() {
|
|
// outfile.open("FGNewEngine.dat", ios::out|ios::trunc);
|
|
}
|
|
|
|
//destructor
|
|
~FGNewEngine() {
|
|
// outfile.close();
|
|
}
|
|
|
|
// set initial default values
|
|
void init(double dt);
|
|
|
|
// update the engine model based on current control positions
|
|
void update();
|
|
|
|
inline void set_IAS( float value ) { IAS = value; }
|
|
inline void set_Throttle_Lever_Pos( float value ) {
|
|
Throttle_Lever_Pos = value;
|
|
}
|
|
inline void set_Propeller_Lever_Pos( float value ) {
|
|
Propeller_Lever_Pos = value;
|
|
}
|
|
inline void set_Mixture_Lever_Pos( float value ) {
|
|
Mixture_Lever_Pos = value;
|
|
}
|
|
// set the magneto switch position
|
|
inline void set_Magneto_Switch_Pos( int value ) {
|
|
mag_pos = value;
|
|
}
|
|
inline void setStarterFlag( bool flag ) {
|
|
starter = flag;
|
|
}
|
|
// set ambient pressure - takes pounds per square foot
|
|
inline void set_p_amb( float value ) {
|
|
p_amb = value * 47.88026;
|
|
// Convert to Pascals
|
|
}
|
|
// set ambient temperature - takes degrees Rankine
|
|
inline void set_T_amb( float value ) {
|
|
T_amb = value * 0.555555555556;
|
|
// Convert to degrees Kelvin
|
|
}
|
|
|
|
// accessors
|
|
inline float get_RPM() const { return RPM; }
|
|
inline float get_Manifold_Pressure() const { return True_Manifold_Pressure; }
|
|
// inline float get_Rho() const { return Rho; }
|
|
inline float get_MaxHP() const { return MaxHP; }
|
|
inline float get_Percentage_Power() const { return Percentage_Power; }
|
|
inline float get_EGT() const { return EGT_degF; } // Returns EGT in Fahrenheit
|
|
inline float get_CHT() const { return CHT_degF; } // Note this returns CHT in Fahrenheit
|
|
inline float get_prop_thrust_SI() const { return prop_thrust; }
|
|
inline float get_prop_thrust_lbs() const { return (prop_thrust * 0.2248); }
|
|
inline float get_fuel_flow_gals_hr() const { return (Fuel_Flow_gals_hr); }
|
|
inline float get_oil_temp() const { return ((current_oil_temp * 1.8) - 459.67); }
|
|
inline bool getRunningFlag() const { return running; }
|
|
inline bool getCrankingFlag() const { return cranking; }
|
|
inline bool getStarterFlag() const { return starter; }
|
|
};
|
|
|
|
|
|
#endif // _IO360_HXX_
|