IDLE SPEED CONTROL [SKYACTIV-D 2.2]

id0140z7952300

Outline

• The PCM controls the fuel injection amount so that the target idle speed according to the engine operation conditions is obtained

Block diagram

ac5wzn00004995

Operation

• The fuel injection amount is controlled so that the actual idle speed is close to the target idle speed.

• The target idle speed is set under various conditions and consists mainly of the following control items.

Fuel injector (2pin type)

Item	Control description	Target idle speed
Feedback Control	The actual idle speed conforms to the target idle speed during normal idling.	800 rpm
Speed control during fast idle increase	The target engine speed is increased for early activation of the catalytic converter after a cold engine start.	1,750 rpm
Engine Speed Control During Warm-up	Approaches the target engine speed during warm-up based on the input signal from engine coolant temperature sensor and intake air temperature sensor.	750―1,500 rpm
Engine speed control during fuel injection amount learning	During fuel injection amount learning, the engine speed is controlled so that it matches the target engine speed.	During auto-learning control 775 rpm During manual learning control 775―2,000 rpm
DPF regeneration control	Controls the engine speed during DPF regeneration control so that it matches the target engine speed.	Auto DPF regeneration 775―925 rpm Compulsory DPF regeneration 1,750 rpm^*

* :If there is incorrect combustion of soot during diesel particulate filter regeneration, the exhaust gas temperature increases which may cause damage to the diesel particulate filter. In this case, post injection is stopped and the engine speed increases to 2,500 rpm. Due to this, low temperature exhaust gas is sent to the oxidation catalytic converter at high speed and the diesel particulate filter is cooled to prevent damage.

Fuel injector (6pin type)

Item	Control description	Target idle speed
Feedback Control	The actual idle speed conforms to the target idle speed during normal idling.	800 rpm
Engine speed control during fuel injection cleaning^*1	While in the P/N position during fuel injection cleaning, controls the engine speed so that it matches the target engine speed.	1,500 rpm
Engine speed control during fuel injection amount learning	During fuel injection amount learning, the engine speed is controlled so that it matches the target engine speed.	During manual learning control 2,000 rpm
DPF regeneration control	Controls the engine speed during DPF regeneration control so that it matches the target engine speed.	Auto DPF regeneration 780―875 rpm Compulsory DPF regeneration 1,750 rpm^*2

*1 :The PCM implements fuel injection control when it determines that the ignition switch is being switched OFF repeatedly while the engine has not been warmed up sufficiently. The accumulation of condensation in the fuel injection system is prevented by increasing the idle speed under no-load conditions and the temperature in the combustion chamber. When the temperature in the combustion chamber increases to the specified temperature, idle speed increase is automatically canceled.

*2 :If there is incorrect combustion of soot during diesel particulate filter regeneration, the exhaust gas temperature increases which may cause damage to the diesel particulate filter. In this case, post injection is stopped and the engine speed increases to 2,500 rpm. Due to this, low temperature exhaust gas is sent to the oxidation catalytic converter at high speed and the diesel particulate filter is cooled to prevent damage.

• The A/C operation information from the A/C pressure sensor is input to prevent the idle speed from decreasing by A/C load. The fuel injection amount is corrected to maintain idle speed when the A/C load is applied.

In addition, the fuel injection amount is corrected to prevent a decrease in speed when the electrical load is applied.