refactor decel fuel cut (#3830)

* refactor dfco

* s

* output channel logs dfco

* slightly cheeky comment

firmware/console/binary/output_channels.txt

@@ -287,6 +287,7 @@ uint16_t rpmAcceleration;dRPM;"RPM/s",1, 0, 0, 0, 0
 	bit launchIsLaunchCondition;
 	bit launchCombinedConditions
 	bit launchActivatePinState
+	bit dfcoActive
 
     uint8_t TEMPLOG_MAP_AT_CYCLE_COUNT;;"", 1, 0, -10000, 10000, 3
     uint8_t boostControllerOutput;;"", 1, 0, -10000, 10000, 0

firmware/console/status_loop.cpp

@@ -661,6 +661,7 @@ static void updateFlags() {
 	engine->outputChannels.isIgnitionEnabledIndicator = engine->limpManager.allowIgnition().value;
 	engine->outputChannels.isInjectionEnabledIndicator = engine->limpManager.allowInjection().value;
 	engine->outputChannels.isCylinderCleanupActivated = engine->isCylinderCleanupMode;
+	engine->outputChannels.dfcoActive = engine->module<DfcoController>()->cutFuel();
 
 #if EFI_LAUNCH_CONTROL
 	engine->outputChannels.launchTriggered = engine->launchController.isLaunchCondition;

firmware/controllers/algo/algo.mk

@@ -22,6 +22,7 @@ CONTROLLERS_ALGO_SRC_CPP = $(PROJECT_DIR)/controllers/algo/advance_map.cpp \
 	$(PROJECT_DIR)/controllers/algo/airmass/speed_density_base.cpp \
 	$(PROJECT_DIR)/controllers/algo/fuel/fuel_computer.cpp \
 	$(PROJECT_DIR)/controllers/algo/fuel/injector_model.cpp \
+	$(PROJECT_DIR)/controllers/algo/fuel/dfco.cpp \
 	$(PROJECT_DIR)/controllers/algo/nmea.cpp \
 	$(PROJECT_DIR)/controllers/algo/defaults/default_base_engine.cpp \
 	$(PROJECT_DIR)/controllers/algo/defaults/default_cranking.cpp \

firmware/controllers/algo/engine.h

@@ -36,6 +36,7 @@
 #include "boost_control.h"
 #include "ignition_controller.h"
 #include "alternator_controller.h"
+#include "dfco.h"
 
 #ifndef EFI_UNIT_TEST
 #error EFI_UNIT_TEST must be defined!
@@ -182,6 +183,7 @@ public:
 		IgnitionController,
 		AcController,
 		PrimeController,
+		DfcoController,
 		EngineModule // dummy placeholder so the previous entries can all have commas
 		> engineModules;
 

firmware/controllers/algo/engine2.cpp

@@ -123,8 +123,7 @@ void EngineState::periodicFastCallback() {
 	// todo: move this into slow callback, no reason for CLT corr to be here
 	running.coolantTemperatureCoefficient = getCltFuelCorrection();
 
-	// Fuel cut-off isn't just 0 or 1, it can be tapered
-	fuelCutoffCorrection = getFuelCutOffCorrection(nowNt, rpm);
+	engine->module<DfcoController>()->update();
 
 	// post-cranking fuel enrichment.
 	// for compatibility reasons, apply only if the factor is greater than unity (only allow adding fuel)

firmware/controllers/algo/engine_state.h

@@ -59,10 +59,6 @@ public:
 	// Angle between firing the main (primary) spark and the secondary (trailing) spark
 	angle_t trailingSparkAngle = 0;
 
-	// fuel-related;
-	float fuelCutoffCorrection = 0;
-	efitick_t coastingFuelCutStartTime = 0;
-
 	efitick_t timeSinceLastTChargeK;
 
 	float currentVe = 0;

firmware/controllers/algo/fuel/dfco.cpp

@@ -0,0 +1,48 @@
+#include "pch.h"
+
+bool DfcoController::getState() const {
+	if (!engineConfiguration->coastingFuelCutEnabled) {
+		return false;
+	}
+
+	auto rpm = Sensor::getOrZero(SensorType::Rpm);
+	const auto [tpsValid, tpsPos] = Sensor::get(SensorType::Tps1);
+	const auto [cltValid, clt] = Sensor::get(SensorType::Clt);
+	const auto [mapValid, map] = Sensor::get(SensorType::Map);
+
+	// If some sensor is broken, inhibit DFCO
+	if (!tpsValid || !cltValid || !mapValid) {
+		return false;
+	}
+
+	bool mapActivate = map < engineConfiguration->coastingFuelCutMap;
+	bool tpsActivate = tpsPos < engineConfiguration->coastingFuelCutTps;
+	bool cltActivate = clt > engineConfiguration->coastingFuelCutClt;
+	// True if throttle, MAP, and CLT are all acceptable for DFCO to occur
+	bool dfcoAllowed = mapActivate && tpsActivate && cltActivate;
+
+	bool rpmActivate = (rpm > engineConfiguration->coastingFuelCutRpmHigh);
+	bool rpmDeactivate = (rpm < engineConfiguration->coastingFuelCutRpmLow);
+
+	// RPM is high enough, and DFCO allowed
+	if (dfcoAllowed && rpmActivate) {
+		return true;
+	}
+
+	// RPM too low, or DFCO not allowed
+	if (!dfcoAllowed || rpmDeactivate) {
+		return false;
+	}
+
+	// No conditions hit, no change to state (provides hysteresis)
+	return m_isDfco;
+}
+
+void DfcoController::update() {
+	// Run state machine
+	m_isDfco = getState();
+}
+
+bool DfcoController::cutFuel() const {
+	return m_isDfco;
+}

firmware/controllers/algo/fuel/dfco.h

@@ -0,0 +1,13 @@
+#pragma once
+
+// DFCO = deceleration fuel cut off, ie, save gas when your foot is off the pedal
+class DfcoController : public EngineModule {
+public:
+	void update();
+
+	bool cutFuel() const;
+
+private:
+	bool getState() const;
+	bool m_isDfco = false;
+};

firmware/controllers/algo/fuel_math.cpp

@@ -280,8 +280,10 @@ float getInjectionMass(int rpm) {
 	float cycleFuelMass = getCycleFuelMass(isCranking, baseFuelMass);
 	efiAssert(CUSTOM_ERR_ASSERT, !cisnan(cycleFuelMass), "NaN cycleFuelMass", 0);
 
-	// Fuel cut-off isn't just 0 or 1, it can be tapered
-	cycleFuelMass *= engine->engineState.fuelCutoffCorrection;
+	if (engine->module<DfcoController>()->cutFuel()) {
+		// If decel fuel cut, zero out fuel
+		cycleFuelMass = 0;
+	}
 
 	float durationMultiplier = getInjectionModeDurationMultiplier();
 	float injectionFuelMass = cycleFuelMass * durationMultiplier;
@@ -347,57 +349,6 @@ float getIatFuelCorrection() {
 	return interpolate2d(iat, config->iatFuelCorrBins, config->iatFuelCorr);
 }
 
-/**
- * @brief	Called from EngineState::periodicFastCallback to update the state.
- * @note The returned value is float, not boolean - to implement taper (smoothed correction).
- * @return	Fuel duration correction for fuel cut-off control (ex. if coasting). No correction if 1.0
- */
-float getFuelCutOffCorrection(efitick_t nowNt, int rpm) {
-	// no corrections by default
-	float fuelCorr = 1.0f;
-
-	// coasting fuel cut-off correction
-	if (engineConfiguration->coastingFuelCutEnabled) {
-		auto [tpsValid, tpsPos] = Sensor::get(SensorType::Tps1);
-		if (!tpsValid) {
-			return 1.0f;
-		}
-
-		const auto [cltValid, clt] = Sensor::get(SensorType::Clt);
-		if (!cltValid) {
-			return 1.0f;
-		}
-
-		const auto [mapValid, map] = Sensor::get(SensorType::Map);
-		if (!mapValid) {
-			return 1.0f;
-		}
-
-		// gather events
-		bool mapDeactivate = (map >= engineConfiguration->coastingFuelCutMap);
-		bool tpsDeactivate = (tpsPos >= engineConfiguration->coastingFuelCutTps);
-		// If no CLT sensor (or broken), don't allow DFCO
-		bool cltDeactivate = clt < (float)engineConfiguration->coastingFuelCutClt;
-		bool rpmDeactivate = (rpm < engineConfiguration->coastingFuelCutRpmLow);
-		bool rpmActivate = (rpm > engineConfiguration->coastingFuelCutRpmHigh);
-		
-		// state machine (coastingFuelCutStartTime is also used as a flag)
-		if (!mapDeactivate && !tpsDeactivate && !cltDeactivate && rpmActivate) {
-			engine->engineState.coastingFuelCutStartTime = nowNt;
-		} else if (mapDeactivate || tpsDeactivate || rpmDeactivate || cltDeactivate) {
-			engine->engineState.coastingFuelCutStartTime = 0;
-		}
-		// enable fuelcut?
-		if (engine->engineState.coastingFuelCutStartTime != 0) {
-			// todo: add taper - interpolate using (nowNt - coastingFuelCutStartTime)?
-			fuelCorr = 0.0f;
-		}
-	}
-	
-	// todo: add other fuel cut-off checks here (possibly cutFuelOnHardLimit?)
-	return fuelCorr;
-}
-
 float getBaroCorrection() {
 	if (Sensor::hasSensor(SensorType::BarometricPressure)) {
 		// Default to 1atm if failed

firmware/controllers/algo/fuel_math.h

@@ -22,7 +22,6 @@ angle_t getInjectionOffset(float rpm, float load);
 float getIatFuelCorrection();
 
 float getCltFuelCorrection();
-float getFuelCutOffCorrection(efitick_t nowNt, int rpm);
 angle_t getCltTimingCorrection();
 float getCrankingFuel(float baseFuel);
 float getCrankingFuel3(float baseFuel, uint32_t revolutionCounterSinceStart);

firmware/tunerstudio/rusefi.input

@@ -1235,6 +1235,7 @@ gaugeCategory = DynoView
 	indicator = { acState }, "AC off", "AC on", white, black, blue, white
 	indicator = { isIdleClosedLoop }, "not idling", "idling", white, black, green, black
 	indicator = { isIdleCoasting }, "not coasting", "coasting", white, black, green, black
+	indicator = { dfcoActive }, "no decel cut", "decel cut", white, black, yellow, black
 
     ; error codes
     indicator = { isTpsError}, "tps",   "tps error",   white, black, red,   black