Encapsulate the interpolstion version of FGEnvironment and fix some bugs

[flightgear.git] / src / FDM / JSBSim / FGPiston.cpp

diff --git a/src/FDM/JSBSim/FGPiston.cpp b/src/FDM/JSBSim/FGPiston.cpp
index dbbc88588c904b7aecba63f3ac8047f6bb1f3a46..263591e48b7baeaab9843b5e9d1739a2a23ae316 100644 (file)
--- a/src/FDM/JSBSim/FGPiston.cpp
+++ b/src/FDM/JSBSim/FGPiston.cpp
@@ -60,33 +60,21 @@ FGPiston::FGPiston(FGFDMExec* exec, FGConfigFile* Eng_cfg) : FGEngine(exec),
 {
   string token;
 
+  Type = etPiston;
+  crank_counter = 0;
+  EngineNumber = 0;
+  OilTemp_degK = 298;
   MinManifoldPressure_inHg = 6.5;
   MaxManifoldPressure_inHg = 28.5;
+  ManifoldPressure_inHg = Atmosphere->GetPressure() * psftoinhg; // psf to in Hg
+  CylinderHeadTemp_degK = 0.0;
   Displacement = 360;
   MaxHP = 200;
   Cycles = 2;
   IdleRPM = 600;
-
-  Name = Eng_cfg->GetValue("NAME");
-  Eng_cfg->GetNextConfigLine();
-  while (Eng_cfg->GetValue() != string("/FG_PISTON")) {
-    *Eng_cfg >> token;
-    if      (token == "MINMP") *Eng_cfg >> MinManifoldPressure_inHg;
-    else if (token == "MAXMP") *Eng_cfg >> MaxManifoldPressure_inHg;
-    else if (token == "DISPLACEMENT") *Eng_cfg >> Displacement;
-    else if (token == "MAXHP") *Eng_cfg >> MaxHP;
-    else if (token == "CYCLES") *Eng_cfg >> Cycles;
-    else if (token == "IDLERPM") *Eng_cfg >> IdleRPM;
-    else if (token == "MAXTHROTTLE") *Eng_cfg >> MaxThrottle;
-    else if (token == "MINTHROTTLE") *Eng_cfg >> MinThrottle;
-    else cerr << "Unhandled token in Engine config file: " << token << endl;
-  }
-
-  Type = etPiston;
-  crank_counter = 0;
-  EngineNumber = 0;
-  OilTemp_degK = 298;
-  ManifoldPressure_inHg = Atmosphere->GetPressure() * psftoinhg; // psf to in Hg
+  Magnetos = 0;
+  ExhaustGasTemp_degK = 0.0;
+  EGT_degC = 0.0;
 
   dt = State->Getdt();
 
@@ -123,6 +111,21 @@ FGPiston::FGPiston(FGFDMExec* exec, FGConfigFile* Eng_cfg) : FGEngine(exec),
   *Power_Mixture_Correlation << 20 <<  74.0;
   *Power_Mixture_Correlation << (14.7/0.6) << 58;
 
+  Name = Eng_cfg->GetValue("NAME");
+  Eng_cfg->GetNextConfigLine();
+  while (Eng_cfg->GetValue() != string("/FG_PISTON")) {
+    *Eng_cfg >> token;
+    if      (token == "MINMP") *Eng_cfg >> MinManifoldPressure_inHg;
+    else if (token == "MAXMP") *Eng_cfg >> MaxManifoldPressure_inHg;
+    else if (token == "DISPLACEMENT") *Eng_cfg >> Displacement;
+    else if (token == "MAXHP") *Eng_cfg >> MaxHP;
+    else if (token == "CYCLES") *Eng_cfg >> Cycles;
+    else if (token == "IDLERPM") *Eng_cfg >> IdleRPM;
+    else if (token == "MAXTHROTTLE") *Eng_cfg >> MaxThrottle;
+    else if (token == "MINTHROTTLE") *Eng_cfg >> MinThrottle;
+    else cerr << "Unhandled token in Engine config file: " << token << endl;
+  }
+
   Debug(0); // Call Debug() routine from constructor if needed
 }
 
@@ -137,7 +140,7 @@ FGPiston::~FGPiston()
 
 double FGPiston::Calculate(double PowerRequired)
 {
-  ConsumeFuel();
+  if (FuelFlow_gph > 0.0) ConsumeFuel();
 
   Throttle = FCS->GetThrottlePos(EngineNumber);
   Mixture = FCS->GetMixturePos(EngineNumber);
@@ -150,7 +153,8 @@ double FGPiston::Calculate(double PowerRequired)
   p_amb_sea_level = Atmosphere->GetPressureSL() * 48;
   T_amb = Atmosphere->GetTemperature() * (5.0 / 9.0);  // convert from Rankine to Kelvin
 
-  RPM = Propulsion->GetThruster(EngineNumber)->GetRPM();
+  RPM = Propulsion->GetThruster(EngineNumber)->GetRPM() *
+        Propulsion->GetThruster(EngineNumber)->GetGearRatio();
     
   IAS = Auxiliary->GetVcalibratedKTS();
 
@@ -334,29 +338,34 @@ void FGPiston::doFuelFlow(void)
 void FGPiston::doEnginePower(void)
 {
   ManifoldPressure_inHg *= p_amb / p_amb_sea_level;
+
   if (Running) {       
     double ManXRPM = ManifoldPressure_inHg * RPM;
-        // FIXME: this needs to be generalized
+    double T_amb_degF = KelvinToFahrenheit(T_amb);
+    double T_amb_sea_lev_degF = KelvinToFahrenheit(288); 
+
+    // FIXME: this needs to be generalized
     Percentage_Power = (6e-9 * ManXRPM * ManXRPM) + (8e-4 * ManXRPM) - 1.0;
-    double T_amb_degF = (T_amb * 1.8) - 459.67;
-    double T_amb_sea_lev_degF = (288 * 1.8) - 459.67; 
-    Percentage_Power =
-      Percentage_Power + ((T_amb_sea_lev_degF - T_amb_degF) * 7 /120);
+    Percentage_Power += ((T_amb_sea_lev_degF - T_amb_degF) * 7 /120);
+
     double Percentage_of_best_power_mixture_power =
       Power_Mixture_Correlation->GetValue(14.7 / equivalence_ratio);
-    Percentage_Power =
-      Percentage_Power * Percentage_of_best_power_mixture_power / 100.0;
-    if (Percentage_Power < 0.0)
-      Percentage_Power = 0.0;
-    else if (Percentage_Power > 100.0)
-      Percentage_Power = 100.0;
+
+    Percentage_Power *= Percentage_of_best_power_mixture_power / 100.0;
+
+    if (Percentage_Power < 0.0) Percentage_Power = 0.0;
+    else if (Percentage_Power > 100.0) Percentage_Power = 100.0;
+    
     HP = Percentage_Power * MaxHP / 100.0;
-  } else {  
+
+  } else {
+
     // Power output when the engine is not running
     if (Cranking) {
       if (RPM < 10) {
-        HP = 3.0;      // This is a hack to prevent overshooting the idle rpm in the first time step
-                    // It may possibly need to be changed if the prop model is changed.
+        HP = 3.0;   // This is a hack to prevent overshooting the idle rpm in
+                    // the first time step. It may possibly need to be changed
+                    // if the prop model is changed.
       } else if (RPM < 480) {
         HP = 3.0 + ((480 - RPM) / 10.0);  
         // This is a guess - would be nice to find a proper starter moter torque curve