EMISSION CONTROL SYSTEM

PM Reduction Control

1. In order to regenerate the DPNR, the temperature of the DPNR is increased to combust the accumulated PM in the DPNR, expelling it as CO2 and H2O.

2. The ECM monitors the engine condition and calculates the total amount of accumulated PM. In addition, the ECM calculates the amount of combusted PM according to the engine speed, fuel injection volume and the injection volume of the exhaust fuel addition injector assembly. The amount of accumulated PM in the DPNR is calculated based on the calculated total amount of accumulated PM and the amount of combusted PM. The ECM urges the driver to perform PM automatic or manual regeneration according to the level of accumulated PM.

3. When automatic or manual regeneration is performed, the injection of the exhaust fuel addition injector assembly and the engine combustion condition are controlled, increasing the temperature of the DPNR. As a result, the temperature of the DPNR becomes approximately 600°C to 700°C and PM is combusted.

4. When the vehicle is continuously driven with a high exhaust temperature such as at high speeds, the temperature of the DPNR is sufficiently increased and PM is spontaneously combusted. At this time, no special control such as exhaust fuel addition injector assembly control, etc. is performed.

5. When the vehicle is continuously driven while the temperature of the DPNR is not high enough for PM combustion such as when driving for a short distance or driving for a short time, catalyst performance is decreased. As a result, PM is accumulated in the DPNR. When the amount of accumulated PM exceeds the threshold (for automatic regeneration), the ECM performs automatic regeneration until the amount of PM reaches zero.

6. If the vehicle continues to be driven for a short distance even after automatic regeneration is performed, more PM is accumulated. When the amount of accumulated PM exceeds the threshold (for manual regeneration), a message is displayed on the multi-information display to urge the driver to perform manual regeneration.

7. Automatic Regeneration

   
   

   • When automatic regeneration is being performed, the ECM controls the fuel injection of the exhaust fuel addition injector assembly and the engine combustion condition, increasing the temperature of the DPNR to combust the PM. Idle up is performed while the vehicle is stopped.

     Tech Tips

     The end of automatic regeneration is calculated by the ECM according to the amount of accumulated PM.

8. Manual Regeneration

   
   

   1. Drive for 20 to 30 minutes at 65 km/h or higher to perform manual regeneration. For details of manual regeneration operation, refer to the Repair Manual.

   2. When manual regeneration is being performed, the ECM controls the fuel injection of the exhaust fuel addition injector assembly and the engine combustion condition, increasing the temperature of the DPNR to combust the PM.

9. Fail-safe

   
   

   • If manual regeneration is performed when the amount of accumulated PM is beyond the threshold, the DPNR may get damaged. Therefore, when the amount of accumulated PM exceeds the threshold (for the fail-safe function), the injection volume is controlled to a minimum level to cancel regeneration control. As a result, manual regeneration cannot be performed properly. At the same time, the MIL illuminates and a message is displayed on the multi-information display to notify the driver of a malfunction.

     Figure 1. Relationship between MIL, Message on Multi-information Display and Regeneration Control (Conceptual Diagram)

     

     Text in Illustration	MIL	Massage on Multi-information Display
     A	-	-
     B	-	-
     C	-	DPF FULL SEE OWNER'S MANUAL
     D	Illuminate	DPF FULL ENGINE SERVICE REQUIRED

     

     *1

     MIL

     *2

     Multi-information Display