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1 : : /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2 : :
3 : : Header: FGPiston.h
4 : : Author: Jon S. Berndt
5 : : Date started: 09/12/2000
6 : :
7 : : ------------- Copyright (C) 2000 Jon S. Berndt (jon@jsbsim.org) --------------
8 : :
9 : : This program is free software; you can redistribute it and/or modify it under
10 : : the terms of the GNU Lesser General Public License as published by the Free Software
11 : : Foundation; either version 2 of the License, or (at your option) any later
12 : : version.
13 : :
14 : : This program is distributed in the hope that it will be useful, but WITHOUT
15 : : ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
16 : : FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
17 : : details.
18 : :
19 : : You should have received a copy of the GNU Lesser General Public License along with
20 : : this program; if not, write to the Free Software Foundation, Inc., 59 Temple
21 : : Place - Suite 330, Boston, MA 02111-1307, USA.
22 : :
23 : : Further information about the GNU Lesser General Public License can also be found on
24 : : the world wide web at http://www.gnu.org.
25 : :
26 : : HISTORY
27 : : --------------------------------------------------------------------------------
28 : : 09/12/2000 JSB Created
29 : : 10/01/2001 DPM Modified to use equations from Dave Luff's piston model.
30 : : 11/01/2008 RKJ Modified piston engine model for more general use.
31 : : %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
32 : : SENTRY
33 : : %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
34 : :
35 : : #ifndef FGPISTON_H
36 : : #define FGPISTON_H
37 : :
38 : : /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
39 : : INCLUDES
40 : : %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
41 : :
42 : : #include "FGEngine.h"
43 : : #include "math/FGTable.h"
44 : :
45 : : /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
46 : : DEFINITIONS
47 : : %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
48 : :
49 : : #define ID_PISTON "$Id: FGPiston.h,v 1.24 2010/08/21 18:08:13 jberndt Exp $";
50 : : #define FG_MAX_BOOST_SPEEDS 3
51 : :
52 : : /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
53 : : FORWARD DECLARATIONS
54 : : %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
55 : :
56 : : namespace JSBSim {
57 : :
58 : : /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
59 : : CLASS DOCUMENTATION
60 : : %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
61 : :
62 : : /** Models Dave Luff's Turbo/Supercharged Piston engine model.
63 : :
64 : : <h3>Configuration File Format:</h3>
65 : :
66 : : @code
67 : : <piston_engine name="{string}">
68 : : <minmp unit="{INHG | PA | ATM}"> {number} </minmp>
69 : : <maxmp unit="{INHG | PA | ATM}"> {number} </maxmp>
70 : : <displacement unit="{IN3 | LTR | CC}"> {number} </displacement>
71 : : <bore unit="{IN | M}"> {number} </bore>
72 : : <stroke unit="{IN | M}"> {number} </stroke>
73 : : <cylinders> {number} </cylinders>
74 : : <compression-ratio> {number} </compression-ratio>
75 : : <sparkfaildrop> {number} </sparkfaildrop>
76 : : <maxhp unit="{HP | WATTS}"> {number} </maxhp>
77 : : <cycles> {number} </cycles>
78 : : <idlerpm> {number} </idlerpm>
79 : : <maxrpm> {number} </maxrpm>
80 : : <maxthrottle> {number} </maxthrottle>
81 : : <minthrottle> {number} </minthrottle>
82 : : <bsfc unit="{LBS/HP*HR | "KG/KW*HR"}"> {number} </bsfc>
83 : : <volumetric-efficiency> {number} </volumetric-efficiency>
84 : : <dynamic-fmep unit="{INHG | PA | ATM}"> {number} </dynamic-fmep>
85 : : <static-fmep unit="{INHG | PA | ATM}"> {number} </static-fmep>
86 : : <numboostspeeds> {number} </numboostspeeds>
87 : : <boostoverride> {0 | 1} </boostoverride>
88 : : <boostmanual> {0 | 1} </boostmanual>
89 : : <ratedboost1 unit="{INHG | PA | ATM}"> {number} </ratedboost1>
90 : : <ratedpower1 unit="{HP | WATTS}"> {number} </ratedpower1>
91 : : <ratedrpm1> {number} </ratedrpm1>
92 : : <ratedaltitude1 unit="{FT | M}"> {number} </ratedaltitude1>
93 : : <ratedboost2 unit="{INHG | PA | ATM}"> {number} </ratedboost2>
94 : : <ratedpower2 unit="{HP | WATTS}"> {number} </ratedpower2>
95 : : <ratedrpm2> {number} </ratedrpm2>
96 : : <ratedaltitude2 unit="{FT | M}"> {number} </ratedaltitude2>
97 : : <ratedboost3 unit="{INHG | PA | ATM}"> {number} </ratedboost3>
98 : : <ratedpower3 unit="{HP | WATTS}"> {number} </ratedpower3>
99 : : <ratedrpm3> {number} </ratedrpm3>
100 : : <ratedaltitude3 unit="{FT | M}"> {number} </ratedaltitude3>
101 : : <takeoffboost unit="{INHG | PA | ATM}"> {number} </takeoffboost>
102 : : <air-intake-impedance-factor> {number} </air-intake-impedance-factor>
103 : : <ram-air-factor> {number} </ram-air-factor>
104 : : </piston_engine>
105 : : @endcode
106 : :
107 : : <pre>
108 : : Additional elements are required for a supercharged engine. These can be
109 : : left off a non-supercharged engine, ie. the changes are all backward
110 : : compatible at present.
111 : :
112 : : - NUMBOOSTSPEEDS - zero (or not present) for a naturally-aspirated engine,
113 : : either 1, 2 or 3 for a boosted engine. This corresponds to the number of
114 : : supercharger speeds. Merlin XII had 1 speed, Merlin 61 had 2, a late
115 : : Griffon engine apparently had 3. No known engine more than 3, although
116 : : some German engines apparently had a continuously variable-speed
117 : : supercharger.
118 : :
119 : : - BOOSTOVERRIDE - whether the boost pressure control system (either a boost
120 : : control valve for superchargers or wastegate for turbochargers) can be
121 : : overriden by the pilot. During wartime this was commonly possible, and
122 : : known as "War Emergency Power" by the Brits. 1 or 0 in the config file.
123 : : This isn't implemented in the model yet though, there would need to be
124 : : some way of getting the boost control cutout lever position (on or off)
125 : : from FlightGear first.
126 : :
127 : : - BOOSTMANUAL - whether a multispeed supercharger will manually or
128 : : automatically shift boost speeds. On manual shifting the boost speeds
129 : : is accomplished by controling propulsion/engine/boostspeed
130 : :
131 : : - The next items are all appended with either 1, 2 or 3 depending on which
132 : : boost speed they refer to, eg RATEDBOOST1. The rated values seems to have
133 : : been a common convention at the time to express the maximum continuously
134 : : available power, and the conditions to attain that power.
135 : :
136 : : - RATEDBOOST[123] - the absolute rated boost above sea level ambient for a
137 : : given boost speed, in psi. Eg the Merlin XII had a rated boost of 9psi,
138 : : giving approximately 42inHg manifold pressure up to the rated altitude.
139 : :
140 : : - RATEDALTITUDE[123] - The altitude up to which rated boost can be
141 : : maintained. Up to this altitude the boost is maintained constant for a
142 : : given throttle position by the BCV or wastegate. Beyond this altitude the
143 : : manifold pressure must drop, since the supercharger is now at maximum
144 : : unregulated output. The actual pressure multiplier of the supercharger
145 : : system is calculated at initialisation from this value.
146 : :
147 : : - RATEDPOWER[123] - The power developed at rated boost at rated altitude at
148 : : rated rpm.
149 : :
150 : : - RATEDRPM[123] - The rpm at which rated power is developed.
151 : :
152 : : - TAKEOFFBOOST - Takeoff boost in psi above ambient. Many aircraft had an
153 : : extra boost setting beyond rated boost, but not totally uncontrolled as in
154 : : the already mentioned boost-control-cutout, typically attained by pushing
155 : : the throttle past a mechanical 'gate' preventing its inadvertant use. This
156 : : was typically used for takeoff, and emergency situations, generally for
157 : : not more than five minutes. This is a change in the boost control
158 : : setting, not the actual supercharger speed, and so would only give extra
159 : : power below the rated altitude. When TAKEOFFBOOST is specified in the
160 : : config file (and is above RATEDBOOST1), then the throttle position is
161 : : interpreted as:
162 : :
163 : : - 0 to 0.95 : idle manifold pressure to rated boost (where attainable)
164 : : - 0.96, 0.97, 0.98 : rated boost (where attainable).
165 : : - 0.99, 1.0 : takeoff boost (where attainable).
166 : :
167 : : A typical takeoff boost for an earlyish Merlin was about 12psi, compared
168 : : with a rated boost of 9psi.
169 : :
170 : : It is quite possible that other boost control settings could have been used
171 : : on some aircraft, or that takeoff/extra boost could have activated by other
172 : : means than pushing the throttle full forward through a gate, but this will
173 : : suffice for now.
174 : :
175 : : Note that MAXMP is still the non-boosted max manifold pressure even for
176 : : boosted engines - effectively this is simply a measure of the pressure drop
177 : : through the fully open throttle.
178 : : </pre>
179 : :
180 : : @author Jon S. Berndt (Engine framework code and framework-related mods)
181 : : @author Dave Luff (engine operational code)
182 : : @author David Megginson (initial porting and additional code)
183 : : @author Ron Jensen (additional engine code)
184 : : @version $Id: FGPiston.h,v 1.24 2010/08/21 18:08:13 jberndt Exp $
185 : : */
186 : :
187 : : /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
188 : : CLASS DECLARATION
189 : : %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
190 : :
191 : : class FGPiston : public FGEngine
192 : : {
193 : : public:
194 : : /// Constructor
195 : : FGPiston(FGFDMExec* exec, Element* el, int engine_number);
196 : : /// Destructor
197 : : ~FGPiston();
198 : :
199 : : std::string GetEngineLabels(const std::string& delimiter);
200 : : std::string GetEngineValues(const std::string& delimiter);
201 : :
202 : : void Calculate(void);
203 : 0 : double GetPowerAvailable(void) {return PowerAvailable;}
204 : : double CalcFuelNeed(void);
205 : :
206 : : void ResetToIC(void);
207 : 0 : void SetMagnetos(int magnetos) {Magnetos = magnetos;}
208 : :
209 : 0 : double GetEGT(void) { return EGT_degC; }
210 : : int GetMagnetos(void) {return Magnetos;}
211 : :
212 : : double getExhaustGasTemp_degF(void) {return KelvinToFahrenheit(ExhaustGasTemp_degK);}
213 : 0 : double getManifoldPressure_inHg(void) const {return ManifoldPressure_inHg;}
214 : 0 : double getCylinderHeadTemp_degF(void) {return KelvinToFahrenheit(CylinderHeadTemp_degK);}
215 : 0 : double getOilPressure_psi(void) const {return OilPressure_psi;}
216 : 0 : double getOilTemp_degF (void) {return KelvinToFahrenheit(OilTemp_degK);}
217 : 0 : double getRPM(void) {return RPM;}
218 : :
219 : : protected:
220 : :
221 : : private:
222 : : int crank_counter;
223 : :
224 : : double IndicatedHorsePower;
225 : : double PMEP;
226 : : double FMEP;
227 : : double FMEPDynamic;
228 : : double FMEPStatic;
229 : : double PowerAvailable;
230 : :
231 : : // timestep
232 : : double dt;
233 : :
234 : : void doEngineStartup(void);
235 : : void doBoostControl(void);
236 : : void doMAP(void);
237 : : void doAirFlow(void);
238 : : void doFuelFlow(void);
239 : : void doEnginePower(void);
240 : : void doEGT(void);
241 : : void doCHT(void);
242 : : void doOilPressure(void);
243 : : void doOilTemperature(void);
244 : :
245 : : int InitRunning(void);
246 : :
247 : : //
248 : : // constants
249 : : //
250 : :
251 : : const double R_air;
252 : : const double rho_fuel; // kg/m^3
253 : : const double calorific_value_fuel; // W/Kg (approximate)
254 : : const double Cp_air; // J/KgK
255 : : const double Cp_fuel; // J/KgK
256 : : const double standard_pressure; //Pa
257 : :
258 : :
259 : : FGTable *Lookup_Combustion_Efficiency;
260 : : FGTable *Mixture_Efficiency_Correlation;
261 : :
262 : : //
263 : : // Configuration
264 : : //
265 : : double MinManifoldPressure_inHg; // Inches Hg
266 : : double MaxManifoldPressure_inHg; // Inches Hg
267 : : double MaxManifoldPressure_Percent; // MaxManifoldPressure / 29.92
268 : : double Displacement; // cubic inches
269 : : double displacement_SI; // cubic meters
270 : : double MaxHP; // horsepower
271 : : double SparkFailDrop; // drop of power due to spark failure
272 : : double Cycles; // cycles/power stroke
273 : : double IdleRPM; // revolutions per minute
274 : : double MaxRPM; // revolutions per minute
275 : : double Bore; // inches
276 : : double Stroke; // inches
277 : : double Cylinders; // number
278 : : double CompressionRatio; // number
279 : : double Z_airbox; // number representing intake impediance before the throttle
280 : : double Z_throttle; // number representing slope of throttle impediance
281 : : double PeakMeanPistonSpeed_fps; // ft/sec speed where intake valves begin to choke. Typically 33-50 fps
282 : : double RatedMeanPistonSpeed_fps; // ft/sec derived from MaxRPM and stroke.
283 : : double Ram_Air_Factor; // number
284 : :
285 : : double StarterHP; // initial horsepower of starter motor
286 : : int BoostSpeeds; // Number of super/turbocharger boost speeds - zero implies no turbo/supercharging.
287 : : int BoostSpeed; // The current boost-speed (zero-based).
288 : : bool Boosted; // Set true for boosted engine.
289 : : int BoostManual; // The raw value read in from the config file - should be 1 or 0 - see description below.
290 : : bool bBoostManual; // Set true if pilot must manually control the boost speed.
291 : : int BoostOverride; // The raw value read in from the config file - should be 1 or 0 - see description below.
292 : : bool bBoostOverride; // Set true if pilot override of the boost regulator was fitted.
293 : : // (Typically called 'war emergency power').
294 : : bool bTakeoffBoost; // Set true if extra takeoff / emergency boost above rated boost could be attained.
295 : : // (Typically by extra throttle movement past a mechanical 'gate').
296 : : double TakeoffBoost; // Sea-level takeoff boost in psi. (if fitted).
297 : : double RatedBoost[FG_MAX_BOOST_SPEEDS]; // Sea-level rated boost in psi.
298 : : double RatedAltitude[FG_MAX_BOOST_SPEEDS]; // Altitude at which full boost is reached (boost regulation ends)
299 : : // and at which power starts to fall with altitude [ft].
300 : : double RatedRPM[FG_MAX_BOOST_SPEEDS]; // Engine speed at which the rated power for each boost speed is delivered [rpm].
301 : : double RatedPower[FG_MAX_BOOST_SPEEDS]; // Power at rated throttle position at rated altitude [HP].
302 : : double BoostSwitchAltitude[FG_MAX_BOOST_SPEEDS - 1]; // Altitude at which switchover (currently assumed automatic)
303 : : // from one boost speed to next occurs [ft].
304 : : double BoostSwitchPressure[FG_MAX_BOOST_SPEEDS - 1]; // Pressure at which boost speed switchover occurs [Pa]
305 : : double BoostMul[FG_MAX_BOOST_SPEEDS]; // Pressure multipier of unregulated supercharger
306 : : double RatedMAP[FG_MAX_BOOST_SPEEDS]; // Rated manifold absolute pressure [Pa] (BCV clamp)
307 : : double TakeoffMAP[FG_MAX_BOOST_SPEEDS]; // Takeoff setting manifold absolute pressure [Pa] (BCV clamp)
308 : : double BoostSwitchHysteresis; // Pa.
309 : :
310 : : double minMAP; // Pa
311 : : double maxMAP; // Pa
312 : : double MAP; // Pa
313 : : double TMAP; // Pa - throttle manifold pressure e.g. before the supercharger boost
314 : : double ISFC; // Indicated specific fuel consumption [lbs/horsepower*hour
315 : :
316 : : //
317 : : // Inputs (in addition to those in FGEngine).
318 : : //
319 : : double p_amb; // Pascals
320 : : double p_ram; // Pascals
321 : : double T_amb; // degrees Kelvin
322 : : double RPM; // revolutions per minute
323 : : double IAS; // knots
324 : : bool Magneto_Left;
325 : : bool Magneto_Right;
326 : : int Magnetos;
327 : :
328 : : //
329 : : // Outputs (in addition to those in FGEngine).
330 : : //
331 : : double rho_air;
332 : : double volumetric_efficiency;
333 : : double map_coefficient;
334 : : double m_dot_air;
335 : : double equivalence_ratio;
336 : : double m_dot_fuel;
337 : : double HP;
338 : : double combustion_efficiency;
339 : : double ExhaustGasTemp_degK;
340 : : double EGT_degC;
341 : : double ManifoldPressure_inHg;
342 : : double CylinderHeadTemp_degK;
343 : : double OilPressure_psi;
344 : : double OilTemp_degK;
345 : : double MeanPistonSpeed_fps;
346 : :
347 : : void Debug(int from);
348 : : };
349 : : }
350 : : //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
351 : : #endif
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