DRIVE-BY-WIRE CONTROL OPERATION [LF, L3]

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Idle Speed Control

• In order to ensure idling stability, the PCM controls the throttle valve and sets an optimal throttle valve opening angle based on the engine operating conditions.

Target throttle valve opening angle determination

• The PCM calculates the intake airflow amount required to provide idling stability (IAC target airflow amount), and according to that, determines the target throttle valve opening angle.

• When the engine is cranking, the PCM sets the IAC target airflow amount according to the engine coolant temperature, and opens the throttle valve to that set value.

IAC target airflow amount

• The IAC target airflow amount is calculated by the PCM by subtracting the estimated value for the intake airflow amount which does not pass through the throttle valve from the calculated intake airflow amount required for idling stability (required volume weight).

Required volumetric airflow amount

― The required volumetric airflow amount is calculated from the target charging efficiency as corrected by the changes in intake airflow amount (due to the difference in vacuum pressure in the areas before and after the throttle valve) and in intake airflow density (which changes according to intake airflow temperature change).

Target charging efficiency

― The target charging efficiency is the charging efficiency* required to match engine operating conditions.

― The target charging efficiency is calculated by adding all necessary corrections matching engine operating conditions to the basic charging efficiency as determined according to engine coolant temperature.

* :Charging efficiency is the ratio of the actual intake airflow amount over the maximum amount of airflow (mass) which can fill a cylinder. This figure grows larger in proportion to the increase in engine load.

Correction

Target

Conditions

Correction amount

A/C load correction

Prevents decrease in idle speed due to A/C operation.

A/C is operating.

A/C operation time→correction

Electrical load correction

Prevents decrease in idle speed due to electrical load operation.

Idle speed during electrical load operation and under any condition during driving

High electrical load→large correction

D-range correction

Prevents decrease in idle speed due to shifting into D-range.

D-range signal is input.

P/S operation→correction

Dashpot correction

Prevents decrease in idle speed due to insufficient intake air amount during deceleration.

Decelerated

Low idle speed when shifted to D range→large correction

Correction at engine start

Prevents decrease in idle speed after engine start.

After cranking and engine start

Low ECT→large correction

Hot engine restart correction

Prevents decrease in idle speed from hot engine restart.

Just after cranking and engine start when the ECT is 60 °C {140 °F} or more the IAT is 40 °C {104 °F} or more

High intake airflow temperature→large correction

Feedback correction A

Sets idle speed to target engine speed.

Idle speed during idling (vehicle is stopped) is over or under the target engine speed (except during test mode).

Actual idle speed

Target engine speed or less→volume increase correction

Target engine speed or more→volume decrease correction

Feedback correction B

Sets to the target engine speed when the idle speed has decreased in the range not corrected by feedback correction A, and prevents a decrease in idle speed.

During deceleration at fully closed throttle, the engine speed is the target engine speed or more and when the feedback correction A is not performed (except during test mode).

Large difference between actual idle speed and target engine speed→large correction

Learning correction

Stores intake air volume changes based on differences between engines and changes due to aged deterioration, and feedback.

During feedback correction A when ECT is 85 °C {185 °F} or more.

During idling→average value of feedback correction A

Volume increase correction at vehicle start

Ensures driveability just after vehicle start.

When the accelerator pedal is depressed while the clutch pedal is kept depressing.

Large APP→large correction

Correction	Target	Conditions	Correction amount
A/C load correction	Prevents decrease in idle speed due to A/C operation.	A/C is operating.	A/C operation time→correction
Electrical load correction	Prevents decrease in idle speed due to electrical load operation.	Idle speed during electrical load operation and under any condition during driving	High electrical load→large correction
D-range correction	Prevents decrease in idle speed due to shifting into D-range.	D-range signal is input.	P/S operation→correction
Dashpot correction	Prevents decrease in idle speed due to insufficient intake air amount during deceleration.	Decelerated	Low idle speed when shifted to D range→large correction
Correction at engine start	Prevents decrease in idle speed after engine start.	After cranking and engine start	Low ECT→large correction
Hot engine restart correction	Prevents decrease in idle speed from hot engine restart.	Just after cranking and engine start when the ECT is 60 °C {140 °F} or more the IAT is 40 °C {104 °F} or more	High intake airflow temperature→large correction
Feedback correction A	Sets idle speed to target engine speed.	Idle speed during idling (vehicle is stopped) is over or under the target engine speed (except during test mode).	Actual idle speed Target engine speed or less→volume increase correction Target engine speed or more→volume decrease correction
Feedback correction B	Sets to the target engine speed when the idle speed has decreased in the range not corrected by feedback correction A, and prevents a decrease in idle speed.	During deceleration at fully closed throttle, the engine speed is the target engine speed or more and when the feedback correction A is not performed (except during test mode).	Large difference between actual idle speed and target engine speed→large correction
Learning correction	Stores intake air volume changes based on differences between engines and changes due to aged deterioration, and feedback.	During feedback correction A when ECT is 85 °C {185 °F} or more.	During idling→average value of feedback correction A
Volume increase correction at vehicle start	Ensures driveability just after vehicle start.	When the accelerator pedal is depressed while the clutch pedal is kept depressing.	Large APP→large correction

Target idle speed

• The target idle speed for various engine operation conditions are as follows:

Idle speed

MTX (Neutral position)	No load: 600—700 rpm Electrical loads¹ ON (38—48 A): 650—750 rpm Electrical loads¹ ON (more than 48 A): 700—800 rpm A/C ON and refrigerant pressure switch (middle) OFF: 700—800 rpm A/C ON and refrigerant pressure switch (middle) ON: 700—800 rpm
ATX (P or N position)	No load: 650—750 rpm Electrical loads¹ ON (38—48 A): 650—750 rpm Electrical loads¹ ON (more than 48 A): 700—800 rpm A/C ON and refrigerant pressure switch (middle) OFF: 650—750 rpm A/C ON and refrigerant pressure switch (middle) ON: 670—770 rpm

*1 :Generator generating current value.

Accelerator Control

• Feedback control has been adopted to the throttle actuator and it is monitored by the TP sensor so that it reaches the target throttle opening angle.

Target throttle opening angle

• Throttle opening angle according to the engine speed and target charging efficiency table has been set.

Target charging efficiency table

• This table has been created by assuming a target charging efficiency according to the engine speed and virtual accelerator opening angle.

Virtual accelerator opening angle

• The virtual accelerator opening angle has been set according to the gear position, vehicle speed, accelerator opening angle, and accelerator opening change rate to improve driveability.

Traction Control

• The PCM calculates the target throttle valve opening angle by the torque up/down request signal from the DSC HU/CM and TCM and the engine speed.

Cruise Control

• Calculates the throttle valve opening angle based on the deviation of the actual vehicle speed from the set vehicle speed which was set with the cruise control switch and sends a duty signal to the throttle valve actuator.

• The PCM controls the actual vehicle speed so that it is close to the set vehicle speed.

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1

Standby

2

Vehicle speed setting

3

Acceleration

4

Deceleration

5

Standby

6

Resume

7

Set vehicle speed

8

Vehicle speed 0 km/h {0 mph}

9

ON/OFF

10

RES ACCEL

11

SET COAST

12

CANCEL

13

ON

14

OFF

15

ACCEL

16

TAP UP

17

RES

18

SET

19

COAST

20

TAP DOWN

21

CANCEL

22

Actual vehicle speed

23

Set vehicle speed

• The cruise control includes the cruise control operation condition and the cruise control stop condition.

Cruise control operation condition

• When all of the following conditions are met, execution of the cruise control system is enabled (cruise control standby status).

― Cruise control main switch: ON

― Vehicle speed: Exceeds 30 km/h {18.6 mph}

Cruise control stop condition

• When any of the following conditions are met even while in cruise control, the PCM stops the cruise control and clears the set vehicle speed.

― Ignition switch: OFF

― Cruise control main switch: OFF

― Cruise control related DTCs (P0564, P0571) detected

• When any of the following conditions are met even while in cruise control, the PCM stops the cruise control while storing the set vehicle speed.

― Cancel switch: ON

― TR switch: P/N position switch: ON

― Vehicle speed: Less than 22.5 km/h {13.9 mph}

― Brake switch: ON

― The actual vehicle speed is 15 km/h {9.3 mph} or more lower than the set vehicle speed during cruise control (ascending).

― Condition where actual vehicle speed is 15 km/h {9.3 mph} or more lower than the set vehicle speed continues for 60 s or more even when the RESUME/ACCEL switch is on.

Cruise control function

• The cruise control includes accelerating, coasting, resume, tap-down, tap-up and downshift functions.

Function List

Function	Contents
Accelerating	• When any of the following conditions are met while driving in cruise control and when the RESUME/ACCEL switch is continuously pressed, the PCM gradually increases the set vehicle speed. ― Except during resume operation ― The RESUME/ACCEL switch is on one time or more during resume operation.
Coasting	• When the SET/COAST switch is continuously pressed, the PCM gradually decreases the set vehicle speed.
Resume	• When the RESUME/ACCEL switch signal is input to the PCM during regular driving (cruise control is stopped) and the previously set vehicle speed is stored in the PCM, the PCM sets the set vehicle speed to the previously set vehicle speed and begins control.
Tap down	• When all of the following conditions are met while driving in cruise control, the PCM decreases the set vehicle speed by 1.6 km/h {1 mph} and controls the throttle valve actuator. ― During cruise control ― RESUME/ACCEL switch off ― The RESUME/ACCEL switch switches from off to on ― When actual vehicle speed is lower (set vehicle speed −2 km/h {-1.2 mph})
Tap-up	• When all of the following conditions are met, the PCM increases the set vehicle speed by 1.6 km/h {1 mph} and controls the throttle valve actuator so that the vehicle speed is close to the set vehicle speed. ― During cruise control ― The RESUME/ACCEL switch switches from off to on
Downshift	• When the following conditions are met, a downshift signal is sent to the TCM via CAN. ― RESUME/ACCEL switch on ― Target vehicle acceleration is not reached

1	Standby
2	Vehicle speed setting
3	Acceleration
4	Deceleration
5	Standby
6	Resume
7	Set vehicle speed
8	Vehicle speed 0 km/h {0 mph}
9	ON/OFF
10	RES ACCEL
11	SET COAST
12	CANCEL
13	ON
14	OFF
15	ACCEL
16	TAP UP
17	RES
18	SET
19	COAST
20	TAP DOWN
21	CANCEL
22	Actual vehicle speed
23	Set vehicle speed