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DIESEL PARTICULATE FILTER REGENERATION CONTROL OPERATION [MZR-CD (RF Turbo)]

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• The PCM estimates the particulate matter (PM) amount accumulated in the diesel particulate filter. Accuracy of the estimation is improved by adding the PM amount estimated based on the drive distance and estimated PM emission to the PM amount estimated based on the difference in exhaust gas pressures. The estimated PM accumulation amount is used for the illumination/flash control of the diesel particulate filter indicator light and MIL, and for diesel particulate filter regeneration control. Estimation methods for estimated PM amount based on the difference in the exhaust gas pressures and distance travelled, and for the estimated PM emission are as follows:

  1. Estimated PM amount based on the difference in the exhaust gas pressures: PM amount is estimated by comparing the exhaust gas pressures before and after the diesel particulate filter based on the signals from the exhaust gas pressure sensor.
  2. Estimated PM emission: Estimated PM emission is the difference between the following estimated soot emission and the estimated PM combustion amount.

  - Estimated soot emission: Soot emission is estimated by determining the customers driving conditions based on the engine speed, vehicle speed signal, intake air amount, and fuel injection amount.
  - Estimated PM combustion amount: PM combustion amount is estimated by storing the record of exhaust gas temperature based on the exhaust gas temperature sensor.

  3. Estimated PM amount based on the distance travelled: PM accumulation amount is estimated from the distance travelled.

• By the diesel particulate filter regeneration control, follow-up injection and post injection are performed to increase the exhaust gas temperature so that the exhaust gas temperature detected by the exhaust gas temperature sensor (middle) matches the target exhaust gas temperature (approx. 620 °C {1148 °F}). In addition, by disabling the EGR control and reducing the intake air amount using the intake shutter valve, the speed of the exhaust gas flow is slowed to increase exhaust gas temperature.

  Note

  • PM spontaneously combusts at approx. 600 °C {1112 °F} or more.

• The PCM suggests the implementation of diesel particulate filter regeneration by illuminating or flashing the diesel particulate filter indicator light or MIL as shown in the following table according to the PM accumulation amount (accumulation rate) in the diesel particulate filter.

Item | Diesel particulate filter accumulation
--- | ---
PM accumulation rate | 0-59 % | 60-79 % | 80-99 % | 100 (Full)-124 % | 125 (1.25 times)-139 % | 140 (1.4 times)-Approx. 200 % (Approx. double) | Approx. 200 % (Approx. double) or more
Diesel particulate filter indicator light | - | - | Illuminates (Informs user) | Flashes every 0.4 s (Warns user)
MIL | - | - | - | - | - | Illuminates (Warns user)
Output restriction | - | - | - | Gas temperature restriction | Gas temperature restriction and soot emission restriction
DTC recorded in PCM | - | - | - | P2458 | P242F
User action | - | - | Let vehicle warm up completely, drive vehicle at 40 km/h {22 mph} or more and engine speed of 2,000 rpm or more for 10 to 15 min, and perform auto regeneration | Bring the vehicle to a dealer
Diesel particulate filter auto regeneration range | - | Diesel particulate filter auto regeneration activates (Auto regeneration activates until PM accumulation rate decreases to 60 % or less) | Diesel particulate filter auto regeneration stops (Output is restricted if PM accumulation rate increases to 100 % or more and auto regeneration is disabled)
Dealer action | - | - | - | Diesel particulate filter manual regeneration (Normal mode) | Diesel particulate filter manual regeneration (Long mode) | Diesel particulate filter replacement

• The diesel particulate filter indicator light flashes when the PM accumulation rate in the diesel particulate filter reaches 100 % or more. In this case, it is indicated that the accumulation capacity of the diesel particulate filter is full, and to reduce the PM amount accumulating in the diesel particulate filter, the fuel injection amount is reduced and exhaust gas temperature restriction (output restriction) is performed. Due to this, soot generation is reduced and PM accumulating in the diesel particulate filter is reduced.
• If the PM accumulation rate reaches 140 % or more, MIL also illuminates. In this case, to restrict soot emission (output restriction), the EGR is controlled to lower the combustion temperature. Due to this, soot emission is further reduced, and PM accumulating in the diesel particulate filter is reduced.
• If the PM accumulation rate in the diesel particulate filter reaches 200 %, the diesel particulate filter has to be replaced.
• For diesel particulate filter regeneration control, auto regeneration in which regeneration is performed automatically based on the accumulation amount (accumulation rate) while the vehicle is driven, and manual regeneration in which regeneration is forcibly performed using the WDS or equivalent while idling are available.

## Diesel Particulate Filter Auto Regeneration Control

• When the PM accumulation rate in the diesel particulate filter is 80 % or more (less than 100 %), the diesel particulate filter indicator light illuminates. In this case, by driving the vehicle for 10 to 15 min. while the following auto regeneration control conditions are all met, PM is combusted and removed to regenerate the diesel particulate filter while the vehicle is driven.
Auto regeneration control condition

  - Engine is completely warmed up
  - Vehicle speed is 40 km/h {22 mph} or more
  - Engine speed is kept at 2,000 rpm or more

• Although the diesel particulate filter indicator light turns off when the diesel particulate filter auto regeneration is started, diesel particulate filter auto regeneration is continued until the PM accumulation rate decreases to 60 % or less.
• If the vehicle is driven at a low speed (low engine speed) for a short distance frequently as follows, it is difficult to combust the PM by the diesel particulate filter auto regeneration, and PM is easily accumulated in the diesel particulate filter. In this case, the diesel particulate filter indicator light illuminates frequently. Therefore, alert the customer to change the driving method such as by driving the vehicle at middle or high engine speeds for a longer distance.

  1. The vehicle is always driven at a speed of 15 km/h {9 mph} or less.
  2. The engine is turned on and off frequently (within 10 min.).
  3. Driving time per one drive is 10 min or less, and stop-and-go driving is frequent.
  4. The vehicle reaches the destination before the engine warms up.
  5. Idling for a long period.

• If the PM accumulation rate in the diesel particulate filter reaches 100 % or more, the fuel injection amount is reduced to restrict output, and the diesel particulate filter auto regeneration is disabled.

## Diesel Particulate Filter Manual Regeneration Control

  Caution

  • Driving the vehicle with the PM accumulation rate in the diesel particulate filter at 100 % or more may cause damage to the diesel particulate filter or the engine. If the PM accumulation rate in the diesel particulate filter is 100 % or more, perform manual regeneration as soon as possible.
  • When performing diesel particulate filter manual regeneration, inform the customer of the fact that PM is easily accumulated in the diesel particulate filter because the vehicle is being driven at a low speed (low engine speed) for a short distance and combustion of PM by diesel particulate filter auto regeneration is difficult. In addition, alert the customer to change the driving method such as by driving the vehicle at middle or high engine speeds for a longer distance.

• Perform diesel particulate filter manual regeneration using the WDS or equivalent.
• In the diesel particulate filter manual regeneration, idle speed is increased up to 1,750 rpm and follow-up injection and post injection are performed to combust the PM and regenerate the diesel particulate filter.

  Caution

  • If electrical load is applied during diesel particulate filter manual regeneration, post injection amount is changed and diesel particulate filter manual regeneration may not be performed correctly. Do not apply electrical load such as turning on the headlights or rear window defroster during diesel particulate filter manual regeneration. A/C is inoperable due to the A/C cut-off control.

• Normal and long modes are available for diesel particulate filter manual regeneration. When "Diesel particulate filter regeneration" is performed using the WDS or equivalent, the PCM automatically selects normal mode or long mode (60 min.) according to the amount of accumulated particulate matter and executes.

  Note

  • During diesel particulate filter manual regeneration, repeat "Diesel particulate filter regeneration" using the WDS or equivalent until the diesel particulate filter indicator light turns off. It may take a maximum of 94 min. until the diesel particulate filter indicator light goes out before the diesel particulate filter manual regeneration is finished.

• In the normal mode, 14 min. regeneration with an engine speed of 1,750 rpm and 3 min. of cooling are performed twice repeatedly.
• In the long mode, idle speed is increased up to 1,750 rpm the same as normal mode, however, regeneration is performed for 60 min. with a lower regeneration temperature due to the reduction in the post injection amount.
• If canceling diesel particulate filter manual regeneration, perform the following procedure:

  1. During diesel particulate filter manual regeneration, depress the clutch pedal and shift to 1st gear. (Keep depressing the clutch pedal.)
  2. Verify that the engine speed decreases from 1,750 to 775 rpm. (Manual regeneration is canceled.)
  3. To stabilize the exhaust gas temperature, shift to neutral soon after the engine speed decreases to 775 rpm, and keep the engine speed at 3,000 rpm for 1 min. (Finished)

  - If diesel particulate filter manual regeneration is to be performed again, leave the vehicle untouched for approx. 5 min. before starting the operation.