table for tcharge interpolation (#3855)

* extract getTChargeCoefficient

* new table

firmware/controllers/algo/rusefi_enums.h

@@ -534,6 +534,7 @@ typedef enum {
 typedef enum {
 	TCHARGE_MODE_RPM_TPS = 0,
 	TCHARGE_MODE_AIR_INTERP = 1,
+	TCHARGE_MODE_AIR_INTERP_TABLE = 2,
 	Force_4bytes_size_tChargeMode_e = ENUM_32_BITS,
 } tChargeMode_e;
 

firmware/controllers/math/speed_density.cpp

@@ -23,6 +23,48 @@ lambda_Map3D_t lambdaMap;
 
 #define tpMin 0
 #define tpMax 100
+
+static float getTChargeCoefficient(int rpm, float tps) {
+	engine->engineState.sd.isTChargeAirModel = engineConfiguration->tChargeMode == TCHARGE_MODE_AIR_INTERP;
+
+	// First, do TPS mode since it doesn't need any of the airflow math.
+	if (engineConfiguration->tChargeMode == TCHARGE_MODE_RPM_TPS) {
+		float minRpmKcurrentTPS = interpolateMsg("minRpm", tpMin,
+				engineConfiguration->tChargeMinRpmMinTps, tpMax,
+				engineConfiguration->tChargeMinRpmMaxTps, tps);
+		float maxRpmKcurrentTPS = interpolateMsg("maxRpm", tpMin,
+				engineConfiguration->tChargeMaxRpmMinTps, tpMax,
+				engineConfiguration->tChargeMaxRpmMaxTps, tps);
+
+		return interpolateMsg("Kcurr", rpmMin, minRpmKcurrentTPS, rpmMax, maxRpmKcurrentTPS, rpm);
+	}
+
+	constexpr floatms_t gramsPerMsToKgPerHour = (3600.0f * 1000.0f) / 1000.0f;
+	// We're actually using an 'old' airMass calculated for the previous cycle, but it's ok, we're not having any self-excitaton issues
+	floatms_t airMassForEngine = engine->engineState.sd.airMassInOneCylinder * engineConfiguration->specs.cylindersCount;
+	// airMass is in grams per 1 cycle for 1 cyl. Convert it to airFlow in kg/h for the engine.
+	// And if the engine is stopped (0 rpm), then airFlow is also zero (avoiding NaN division)
+	floatms_t airFlow = (rpm == 0) ? 0 : airMassForEngine * gramsPerMsToKgPerHour / getEngineCycleDuration(rpm);
+
+	if (engineConfiguration->tChargeMode == TCHARGE_MODE_AIR_INTERP) {
+		// just interpolate between user-specified min and max coefs, based on the max airFlow value
+		return interpolateClamped(
+			0.0, engineConfiguration->tChargeAirCoefMin,
+			engineConfiguration->tChargeAirFlowMax, engineConfiguration->tChargeAirCoefMax,
+			airFlow
+		);
+	} else if (engineConfiguration->tChargeMode == TCHARGE_MODE_AIR_INTERP_TABLE) {
+		return interpolate2d(
+			airFlow,
+			engineConfiguration->tchargeBins,
+			engineConfiguration->tchargeValues
+		);
+	} else {
+		firmwareError(OBD_PCM_Processor_Fault, "Unexpected tChargeMode: %d", engineConfiguration->tChargeMode);
+		return 0;
+	}
+}
+
 //  http://rusefi.com/math/t_charge.html
 /***panel:Charge Temperature*/
 temperature_t getTCharge(int rpm, float tps) {
@@ -47,37 +89,18 @@ temperature_t getTCharge(int rpm, float tps) {
 
 	float coolantTemp = clt.Value;
 
-	if ((engine->engineState.sd.isTChargeAirModel = (engineConfiguration->tChargeMode == TCHARGE_MODE_AIR_INTERP))) {
+	auto coefficient = getTChargeCoefficient(rpm, tps);
-		const floatms_t gramsPerMsToKgPerHour = (3600.0f * 1000.0f) / 1000.0f;
+	engine->engineState.sd.Tcharge_coff = coefficient;
-		// We're actually using an 'old' airMass calculated for the previous cycle, but it's ok, we're not having any self-excitaton issues
-		floatms_t airMassForEngine = engine->engineState.sd.airMassInOneCylinder * engineConfiguration->specs.cylindersCount;
-		// airMass is in grams per 1 cycle for 1 cyl. Convert it to airFlow in kg/h for the engine.
-		// And if the engine is stopped (0 rpm), then airFlow is also zero (avoiding NaN division)
-		floatms_t airFlow = (rpm == 0) ? 0 : airMassForEngine * gramsPerMsToKgPerHour / getEngineCycleDuration(rpm);
-		// just interpolate between user-specified min and max coefs, based on the max airFlow value
-		engine->engineState.sd.Tcharge_coff = interpolateClamped(0.0,
-				engineConfiguration->tChargeAirCoefMin,
-				engineConfiguration->tChargeAirFlowMax,
-				engineConfiguration->tChargeAirCoefMax, airFlow);
-		// save it for console output (instead of MAF massAirFlow)
-	} else {
-		float minRpmKcurrentTPS = interpolateMsg("minRpm", tpMin,
-				engineConfiguration->tChargeMinRpmMinTps, tpMax,
-				engineConfiguration->tChargeMinRpmMaxTps, tps);
-		float maxRpmKcurrentTPS = interpolateMsg("maxRpm", tpMin,
-				engineConfiguration->tChargeMaxRpmMinTps, tpMax,
-				engineConfiguration->tChargeMaxRpmMaxTps, tps);
 
-		engine->engineState.sd.Tcharge_coff = interpolateMsg("Kcurr", rpmMin, minRpmKcurrentTPS, rpmMax, maxRpmKcurrentTPS, rpm);
+	if (cisnan(coefficient)) {
-	}
-
-	if (cisnan(engine->engineState.sd.Tcharge_coff)) {
 		warning(CUSTOM_ERR_T2_CHARGE, "t2-getTCharge NaN");
 		return coolantTemp;
 	}
 
-	// We use a robust interp. function for proper tcharge_coff clamping.
+	// Interpolate between CLT and IAT:
-	float Tcharge = interpolateClamped(0.0f, coolantTemp, 1.0f, airTemp, engine->engineState.sd.Tcharge_coff);
+	// 0.0 coefficient -> use CLT (full heat transfer)
+	// 1.0 coefficient -> use IAT (no heat transfer)
+	float Tcharge = interpolateClamped(0.0f, coolantTemp, 1.0f, airTemp, coefficient);
 
 	if (cisnan(Tcharge)) {
 		// we can probably end up here while resetting engine state - interpolation would fail

firmware/integration/rusefi_config.txt

@@ -1237,7 +1237,10 @@ int16_t tps2Max;Full throttle#2. tpsMax value as 10 bit ADC value. Not Voltage!\
 
 	float boostCutPressure;+MAP value above which fuel is cut in case of overboost.\nSet to 0 to disable overboost cut.;"kPa (absolute)", 1, 0, 0, 500, 0
 
-float[16] unusedMapAccelTaperBins;;"counter", 1, 0, 0, 300, 0
+	uint8_t[16] tchargeBins;;"kg/h", 5, 0, 0, 1200, 0
+	uint8_t[16] tchargeValues;;"ratio", 0.01, 0, 0, 1, 2
+
+float[8] unusedMapAccelTaperBins;;"counter", 1, 0, 0, 300, 0
 
 	float fixedTiming;Fixed timing, useful for TDC testing;"deg", 1, 0, -720, 720, 2
 	float mapLowValueVoltage;MAP voltage for low point;"v", 1, 0, 0, 10, 2
@@ -1388,8 +1391,8 @@ float tChargeAirFlowMax;High flow point for heat transfer estimation.\nSet this
 float tChargeAirIncrLimit;Maximum allowed rate of increase allowed for the estimated charge temperature;"deg/sec", 1, 0, 0, 100, 1
 float tChargeAirDecrLimit;Maximum allowed rate of decrease allowed for the estimated charge temperature;"deg/sec", 1, 0, 0, 100, 1
 
-#define tChargeMode_e_enum "RPM+TPS (Default)", "Air Mass Interpolation"
+#define tChargeMode_e_enum "RPM+TPS (Default)", "Air Mass Interpolation", "Table"
-custom tChargeMode_e 4 bits, U32, @OFFSET@, [0:0], @@tChargeMode_e_enum@@
+custom tChargeMode_e 4 bits, U32, @OFFSET@, [0:1], @@tChargeMode_e_enum@@
 tChargeMode_e tChargeMode;
 
 		float[ETB_BIAS_CURVE_LENGTH] etbBiasBins;target TPS value, 0 to 100%\nTODO: use int8 data date once we template interpolation method;"target TPS position", 1, 0, 0, 100, 0

firmware/tunerstudio/rusefi.input

@@ -644,6 +644,14 @@ enable2ndByteCanID = false
 		yBins       = wwBetaMapValues
 		gauge       = MAPGauge
 
+	curve = tchargeCurve, "Charge temperature estimation coefficient"
+		columnLabel = "flow", "coefficient"
+		xAxis = 0, 500, 6
+		yAxis = 0, 100, 5
+		xBins = tchargeBins, mafEstimate
+		yBins = tchargeValues
+		gauge = tChargeGauge
+
 [TableEditor]
    ;       table_id,    map3d_id,    "title",      page
 
@@ -1829,6 +1837,7 @@ cmd_set_engine_type_default					= "@@TS_IO_TEST_COMMAND_char@@\x00\x31\x00\x00"
 		panel = tChargeGeneralSettings
 		panel = tChargeRpmTpsSettings, { tChargeMode == 0}
 		panel = tChargeAirInterpSettings, { tChargeMode == 1}
+		panel = tchargeCurve, { tChargeMode == 2 }
 
 	dialog = baseInjection, "General"
 		field = "Enabled",						isInjectionEnabled