dfco delay (#4482)

* dfco delay

* config

* using a function that doesn't exist? who does that

* test new behavior

* clearer test

firmware/controllers/algo/fuel/dfco.cpp

@@ -51,13 +51,21 @@ void DfcoController::update() {
 	// If fuel is cut, reset the timer
 	if (newState) {
 		m_timeSinceCut.reset();
+	} else {
+		// If fuel is not cut, reset the not-cut timer
+		m_timeSinceNoCut.reset();
 	}
 
 	m_isDfco = newState;
 }
 
 bool DfcoController::cutFuel() const {
-	return m_isDfco;
+	float cutDelay = engineConfiguration->dfcoDelay;
+
+	// 0 delay means cut immediately, aka timer has always expired
+	bool hasBeenDelay = (cutDelay == 0) || m_timeSinceNoCut.hasElapsedSec(cutDelay);
+
+	return m_isDfco && hasBeenDelay;
 }
 
 float DfcoController::getTimeSinceCut() const {

firmware/controllers/algo/fuel/dfco.h

@@ -14,4 +14,5 @@ private:
 	bool m_isDfco = false;
 
 	Timer m_timeSinceCut;
+	Timer m_timeSinceNoCut;
 };

firmware/integration/rusefi_config.txt

@@ -1429,7 +1429,9 @@ tChargeMode_e tChargeMode;
 
 	uint8_t autoscale maxCamPhaseResolveRpm;Below this RPM, use camshaft information to synchronize the crank's position for full sequential operation. Use this if your cam sensor does weird things at high RPM. Set to 0 to disable, and always use cam to help sync crank.;"rpm", 50, 0, 0, 12500, 0
 
-	int8_t[11] unused4080;;"", 1, 0, 0, 0, 0
+	uint8_t autoscale dfcoDelay;Delay before cutting fuel. Set to 0 to cut immediately with no delay. May cause rumbles and pops out of your exhaust...;"sec", 0.1, 0, 0, 10, 1
+
+	int8_t[10] unused4080;;"", 1, 0, 0, 0, 0
 
 ! Someday there will be a 6th option for BMW S55 that uses a separate shaft just for HPFP
 #define hpfp_cam_e_enum "NONE", "Intake 1", "Exhaust 1", "Intake 2", "Exhaust 2"

firmware/tunerstudio/rusefi.input

@@ -3886,6 +3886,7 @@ dialog = tcuControls, "Transmission Settings"
 		field = "Vehicle speed restore below",	coastingFuelCutVssLow, {coastingFuelCutEnabled == 1}
 		field = "Cut fuel below TPS",			coastingFuelCutTps, {coastingFuelCutEnabled == 1}
 		field = "Cut fuel below MAP",      coastingFuelCutMap, {coastingFuelCutEnabled == 1}
+		field = "Fuel cut delay", dfcoDelay, {coastingFuelCutEnabled == 1}
 		field = "Inhibit closed loop fuel after cut", noFuelTrimAfterDfcoTime, {coastingFuelCutEnabled == 1}
 
     dialog = rotaryDialog, "Rotary"

unit_tests/tests/ignition_injection/test_fuelCut.cpp

@@ -11,6 +11,10 @@
 
 using ::testing::_;
 
+// Define some helpers for not-cut and cut
+#define EXPECT_NORMAL() EXPECT_FLOAT_EQ(normalInjDuration, engine->injectionDuration)
+#define EXPECT_CUT() EXPECT_FLOAT_EQ(0, engine->injectionDuration)
+
 TEST(fuelCut, coasting) {
 	EngineTestHelper eth(TEST_ENGINE);
 	EXPECT_CALL(*eth.mockAirmass, getAirmass(_))
@@ -49,10 +53,6 @@ TEST(fuelCut, coasting) {
 	// process
 	eth.engine.periodicFastCallback();
 
-	// Define some helpers for not-cut and cut
-	#define EXPECT_NORMAL() EXPECT_FLOAT_EQ(normalInjDuration, engine->injectionDuration)
-	#define EXPECT_CUT() EXPECT_FLOAT_EQ(0, engine->injectionDuration)
-
 	// this is normal injection mode (the throttle is opened), no fuel cut-off
 	EXPECT_NORMAL();
 
@@ -130,3 +130,73 @@ TEST(fuelCut, coasting) {
 	EXPECT_CUT();
 }
 
+TEST(fuelCut, delay) {
+	EngineTestHelper eth(TEST_ENGINE);
+	EXPECT_CALL(*eth.mockAirmass, getAirmass(_))
+		.WillRepeatedly(Return(AirmassResult{0.1008f, 50.0f}));
+
+	// configure coastingFuelCut
+	engineConfiguration->coastingFuelCutEnabled = true;
+	engineConfiguration->coastingFuelCutRpmLow = 1300;
+	engineConfiguration->coastingFuelCutRpmHigh = 1500;
+	engineConfiguration->coastingFuelCutTps = 2;
+	engineConfiguration->coastingFuelCutClt = 30;
+	engineConfiguration->coastingFuelCutMap = 100;
+	// set cranking threshold
+	engineConfiguration->cranking.rpm = 999;
+
+	// delay is 1 second
+	engineConfiguration->dfcoDelay = 1.0f;
+
+	// basic engine setup
+	setupSimpleTestEngineWithMafAndTT_ONE_trigger(&eth);
+
+	Sensor::setMockValue(SensorType::Map, 0);
+
+	// mock CLT - just above threshold ('hot engine')
+	float hotClt = engineConfiguration->coastingFuelCutClt + 1;
+	Sensor::setMockValue(SensorType::Clt, hotClt);
+	// mock TPS - throttle is opened
+	Sensor::setMockValue(SensorType::DriverThrottleIntent, 60);
+	// set 'running' RPM - just above RpmHigh threshold
+	Sensor::setMockValue(SensorType::Rpm, engineConfiguration->coastingFuelCutRpmHigh + 1);
+	// 'advance' time (amount doesn't matter)
+	eth.moveTimeForwardUs(1000);
+
+	const float normalInjDuration = 1.5f;
+
+	extern int timeNowUs;
+	timeNowUs = 1e6;
+
+	// process
+	eth.engine.periodicFastCallback();
+
+	// this is normal injection mode (the throttle is opened), no fuel cut-off
+	EXPECT_NORMAL();
+
+	// 'releasing' the throttle
+	Sensor::setMockValue(SensorType::DriverThrottleIntent, 0);
+	eth.engine.periodicFastCallback();
+
+	// Shouldn't cut yet, since not enough time has elapsed
+	EXPECT_NORMAL();
+
+	// Change nothing else, but advance time and update again
+	timeNowUs += 0.9e6;
+	eth.engine.periodicFastCallback();
+
+	// too soon, still no cut
+	EXPECT_NORMAL();
+
+	// Change nothing else, but advance time and update again
+	timeNowUs += 0.2e6;
+	eth.engine.periodicFastCallback();
+
+	// Should now be cut!
+	EXPECT_CUT();
+
+	// Put the throtle back, and it should come back instantly
+	Sensor::setMockValue(SensorType::DriverThrottleIntent, 30);
+	eth.engine.periodicFastCallback();
+	EXPECT_NORMAL();
+}