add fuel computer

firmware/controllers/algo/algo.mk

@@ -16,3 +16,4 @@ CONTROLLERS_ALGO_SRC_CPP = $(PROJECT_DIR)/controllers/algo/advance_map.cpp \
 	$(PROJECT_DIR)/controllers/algo/airmass/maf_airmass.cpp \
 	$(PROJECT_DIR)/controllers/algo/airmass/speed_density_airmass.cpp \
 	$(PROJECT_DIR)/controllers/algo/airmass/speed_density_base.cpp \
+	$(PROJECT_DIR)/controllers/algo/fuel/fuel_computer.cpp \

firmware/controllers/algo/fuel/fuel_computer.cpp

@@ -0,0 +1,27 @@
+#include "fuel_computer.h"
+
+EXTERN_ENGINE;
+
+mass_t FuelComputerBase::getCycleFuel(mass_t airmass, int rpm, float load) const {
+	float stoich = getStoichiometricRatio();
+	float lambda = getTargetLambda(rpm, load);
+	float afr = stoich * lambda;
+
+	ENGINE(engineState.targetAFR) = afr;
+
+	return airmass / afr;
+}
+
+FuelComputer::FuelComputer(const ValueProvider3D& afrTable) : m_afrTable(&afrTable) {}
+
+float FuelComputer::getStoichiometricRatio() const {
+	// TODO: vary this with ethanol content/configured setting/whatever
+	return 14.7f;
+}
+
+float FuelComputer::getTargetLambda(int rpm, float load) const {
+	efiAssert(OBD_PCM_Processor_Fault, m_afrTable != nullptr, "AFR table null", 0);
+
+	// TODO: set the table value in lambda instead of afr
+	return m_afrTable->getValue(rpm, load) / getStoichiometricRatio();
+};

firmware/controllers/algo/fuel/fuel_computer.h

@@ -0,0 +1,36 @@
+#pragma once
+
+#include "engine.h"
+
+class ValueProvider3D;
+
+using mass_t = float;
+
+struct IFuelComputer {
+	virtual mass_t getCycleFuel(mass_t airmass, int rpm, float load) const = 0;
+};
+
+// This contains the math of the fuel model, but doesn't actually read any configuration
+class FuelComputerBase : public IFuelComputer {
+public:
+	mass_t getCycleFuel(mass_t airmass, int rpm, float load) const override;
+
+protected:
+	virtual float getStoichiometricRatio() const = 0;
+	virtual float getTargetLambda(int rpm, float load) const = 0;
+};
+
+// This class is a usable implemenation of a fuel model that reads real configuration
+class FuelComputer final : public FuelComputerBase {
+	DECLARE_ENGINE_PTR;
+
+public:
+	FuelComputer(const ValueProvider3D& afrTable);
+
+protected:
+	float getStoichiometricRatio() const override;
+	float getTargetLambda(int rpm, float load) const override;
+
+private:
+	const ValueProvider3D* const m_afrTable;
+};

firmware/controllers/controllers.mk

@@ -56,6 +56,7 @@ CONTROLLERS_INC=\
 	$(CONTROLLERS_DIR)/system/timer \
 	$(CONTROLLERS_DIR)/algo \
 	$(CONTROLLERS_DIR)/algo/airmass \
+	$(CONTROLLERS_DIR)/algo/fuel \
 	$(CONTROLLERS_DIR)/engine_cycle \
 	$(CONTROLLERS_DIR)/trigger/decoders \
 	$(CONTROLLERS_DIR)/trigger \