EGR CONTROL [SKYACTIV-X 2.0]
id0140hf161400
Outline
• To recirculate an optimum amount of exhaust gas to the combustion chamber according to the engine operation conditions, the PCM controls the EGR valve to open and close the valve.
Block Diagram
Operation
Target EGR valve opening angle calculation method
1. The PCM determines the target EGR rate so that the EGR volume is optimized according to the engine operation conditions. The target EGR rate is calculated based on the basic EGR rate.
-
Basic EGR rate
-
• The EGR rate is calculated according to the engine speed and the charging efficiency*1.
*1 :Charging efficiency is the ratio of the actual amount of intake air to the maximum air charging amount (mass volume) of the cylinder. This value increases proportionately to the increase in engine load.
2. The PCM determines the target EGR flow amount so that the target EGR rate is achieved.
-
Target EGR flow amount
-
• Calculated based on the engine speed and intake air amount information.
-
• The PCM calculates the target EGR valve opening angle to achieve the target EGR flow amount, and then controls the DC motor output so that the target EGR valve opening angle and the actual EGR valve opening angle match.
Target EGR valve opening angle
-
― Calculated based on the information such as the barometric pressure sensor and the MAP sensor information.
Inhibition conditions
-
• To improve drive ability and ensure exhaust emission performance, the EGR valve fully closes when any of the following conditions is met.
-
― Ignition is switched OFF or ignition is switched to ACC or ON (engine off)
― During deceleration
― Idling at engine speed of 1,000 rpm or less
― There is a freezing concern with intake system (when driving in cold weather at extremely low temperatures)
