Option to disable closed loop idle when coasting in gear

firmware/controllers/actuators/idle_thread.cpp

@@ -57,7 +57,14 @@ IIdleController::Phase IdleController::determinePhase(float rpm, float targetRpm
 	float maximumIdleRpm = targetRpm + engineConfiguration->idlePidRpmUpperLimit;
 	looksLikeCoasting = rpm > maximumIdleRpm;
 	looksLikeCrankToIdle = crankingTaperFraction < 1;
-	if (looksLikeCoasting && !looksLikeCrankToIdle) {
+
+	// if car is gear, disable closed loop idle
+	// this applies to cars like NA/NB miatas where the clutch up switch only returns true if also in gear
+	bool transmissionInGear = engineConfiguration->disableIdleClutchUp 
+		&& isBrainPinValid(engineConfiguration->clutchUpPin)
+		&& engine->engineState.clutchUpState;
+
+	if ( (looksLikeCoasting || transmissionInGear) && !looksLikeCrankToIdle) {
 		return Phase::Coasting;
 	}
 

firmware/controllers/actuators/idle_thread_io.cpp

@@ -58,10 +58,9 @@ percent_t getIdlePosition() {
 
 void startPedalPins() {
 #if EFI_PROD_CODE
-	// this is neutral/no gear switch input. on Miata it's wired both to clutch pedal and neutral in gearbox
-	// this switch is not used yet
 	startInputPinIfValid("clutch down switch", engineConfiguration->clutchDownPin, engineConfiguration->clutchDownPinMode);
 
+	// this is neutral/no gear switch input. on Miata it's wired both to clutch pedal and neutral in gearbox
 	startInputPinIfValid("clutch up switch", engineConfiguration->clutchUpPin, engineConfiguration->clutchUpPinMode);
 
 	startInputPinIfValid("throttle pedal up switch", engineConfiguration->throttlePedalUpPin, engineConfiguration->throttlePedalUpPinMode);

firmware/integration/rusefi_config.txt

@@ -988,6 +988,7 @@ bit useSeparateAdvanceForCranking,"Table","Fixed (auto taper)";In Constant mode,
 bit useAdvanceCorrectionsForCranking;This enables the various ignition corrections during cranking (IAT, CLT, FSIO and PID idle).\nYou probably don't need this.
 bit flexCranking;Enable a second cranking table to use for E100 flex fuel, interpolating between the two based on flex fuel sensor.
 bit useIacPidMultTable;This flag allows to use a special 'PID Multiplier' table (0.0-1.0) to compensate for nonlinear nature of IAC-RPM controller
+bit disableIdleClutchUp;Disable closed loop idle if ClutchUp is true.  Only works for vehicles where the signal is only present when in gear, like NA/NB miatas.  This helps prevent integral saturation while coasting at low RPM
 bit isBoostControlEnabled
 bit launchSmoothRetard;Interpolates the Ignition Retard from 0 to 100% within the RPM Range
 bit isPhaseSyncRequiredForIgnition;Some engines are OK running semi-random sequential while other engine require phase synchronization

firmware/tunerstudio/tunerstudio.template.ini

@@ -3368,6 +3368,7 @@ cmd_set_engine_type_default					= "@@TS_IO_TEST_COMMAND_char@@@@ts_command_e_TS_
 		field = "RPM upper limit",	idlePidRpmUpperLimit
 		field = "RPM deadzone",	idlePidRpmDeadZone
 		field = "Max vehicle speed", maxIdleVss
+		field = "Disable Idle in Gear",		disableIdleClutchUp, {clutchUpPin != @@ADC_CHANNEL_NONE@@}
 
 	dialog = idleExtra, "Extra Idle Features"
 		field = "Use idle ignition table",	useSeparateAdvanceForIdle

unit_tests/tests/test_idle_controller.cpp

@@ -105,6 +105,26 @@ TEST(idle_v2, testDeterminePhase) {
 	// Below TPS but above RPM should be outside the zone
 	EXPECT_EQ(ICP::Coasting, dut.determinePhase(1101, 1000, 0, 0, 10));
 	EXPECT_EQ(ICP::Coasting, dut.determinePhase(5000, 1000, 0, 0, 10));
+
+	// enable feature to prevent idle state when coasting in gear
+	engineConfiguration->disableIdleClutchUp = true;
+	setMockState(engineConfiguration->clutchUpPin, false);
+	engineConfiguration->clutchUpPin = Gpio::G2;
+	engineConfiguration->clutchUpPinMode = PI_PULLDOWN;
+	engine->updateSwitchInputs();
+
+	// should be same behaviour as before when clutch is pressed/car in neutral
+	EXPECT_EQ(ICP::Idling, dut.determinePhase(1099, 1000, 0, 0, 10));
+	EXPECT_EQ(ICP::Coasting, dut.determinePhase(1101, 1000, 0, 0, 10));
+	EXPECT_EQ(ICP::CrankToIdleTaper, dut.determinePhase(1000, 1000, 0, 0, 0.5f));
+	EXPECT_EQ(ICP::Running, dut.determinePhase(1000, 1000, 10, 0, 10));
+
+	// clutchUp indicates car in gear with clutch not pressed, should recognize as coasting instead of idle now
+	setMockState(engineConfiguration->clutchUpPin, true);
+	engine->updateSwitchInputs();
+	EXPECT_EQ(ICP::Coasting, dut.determinePhase(1099, 1000, 0, 0, 10));
+	EXPECT_EQ(ICP::Coasting, dut.determinePhase(1101, 1000, 0, 0, 10));
+
 }
 
 TEST(idle_v2, crankingOpenLoop) {
@@ -528,4 +548,4 @@ TEST(idle_v2, IntegrationClamping) {
 
 	// Result would be 75 + 75 = 150, but it should clamp to 100
 	EXPECT_EQ(100, dut.getIdlePosition(950));
-}
+}