Troubleshooting Emissions Faults in Kobelco SK350LC-10 with Hino Engine

[MikePhua]

The Kobelco SK350LC-10 is a highly efficient, technologically advanced tracked hydraulic excavator used in a variety of heavy-duty applications. It is powered by a Hino engine, known for its reliability and performance in demanding conditions. However, like many modern machines equipped with advanced emission systems, the SK350LC-10 is susceptible to emissions faults that can impair performance. This article will focus on diagnosing and solving emissions-related problems, particularly those related to the Hino engine found in the Kobelco SK350LC-10.
Overview of Kobelco SK350LC-10
The Kobelco SK350LC-10 is part of Kobelco’s 10th generation of excavators, designed to offer both power and fuel efficiency. This model features a 261-horsepower engine that delivers superior performance in a variety of tough environments, including construction, mining, and excavation.
One of the standout features of the SK350LC-10 is its compliance with stringent emissions regulations, which is made possible by advanced technology including the Diesel Particulate Filter (DPF) and Selective Catalytic Reduction (SCR) systems. These systems work together to reduce harmful emissions such as nitrogen oxides (NOx) and particulate matter (PM) that can negatively impact the environment and human health.
While these systems contribute to cleaner operations, they can sometimes lead to issues if not properly maintained, and troubleshooting emissions faults is critical for keeping the machine running smoothly.
Common Emissions Faults in the Kobelco SK350LC-10
The emissions system in modern excavators like the Kobelco SK350LC-10 is a complex setup that includes multiple components such as the DPF, SCR, and the engine control unit (ECU). These components are responsible for reducing harmful emissions and ensuring the engine operates efficiently. However, faults in the emissions system can cause significant issues, including loss of power, excessive fuel consumption, and even engine failure.
1. Diesel Particulate Filter (DPF) Blockage
The Diesel Particulate Filter (DPF) is responsible for trapping and storing particulate matter from the engine exhaust gases. Over time, as the DPF fills up with soot, it needs to be cleaned or "regenerated" to prevent it from becoming clogged. If the regeneration process is not carried out properly, the DPF can become blocked, leading to poor engine performance and increased emissions.
Symptoms of a blocked DPF include:

• Loss of engine power
  
• Increased fuel consumption
  
• Warning lights on the dashboard
  
• Abnormal engine temperatures
  

Solution:

• Perform a forced regeneration of the DPF using the excavator's diagnostic tool.
  
• If the DPF is too clogged to regenerate, it may need to be cleaned or replaced.
  

2. Selective Catalytic Reduction (SCR) Issues
The SCR system in the Kobelco SK350LC-10 is designed to reduce NOx emissions by injecting urea into the exhaust stream, which reacts with the NOx to produce nitrogen and water vapor. If the SCR system malfunctions, it can cause emissions faults and trigger warning lights on the dashboard. Common issues include urea injector failure, clogged SCR catalyst, or issues with the urea tank sensor.
Symptoms of SCR system failure include:

• Warning lights indicating SCR malfunction
  
• Reduced engine power or performance
  
• Increased exhaust temperatures
  

Solution:

• Inspect the urea injector and SCR catalyst for any blockages or damage.
  
• Ensure the urea tank is filled with the correct solution (typically, a 32.5% urea solution is required).
  
• Use diagnostic tools to check for faults in the SCR system and replace any malfunctioning components.
  

3. Exhaust Gas Recirculation (EGR) System Problems
The Exhaust Gas Recirculation (EGR) system is designed to recirculate a portion of the engine's exhaust gases back into the combustion chamber to reduce NOx emissions. Over time, the EGR valve or cooler can become clogged with carbon deposits, which can lead to poor engine performance and emissions faults.
Symptoms of EGR system failure include:

• Engine misfires or rough idling
  
• Increased exhaust smoke or emissions
  
• Reduced fuel efficiency
  

Solution:

• Clean or replace the EGR valve and cooler if necessary.
  
• Ensure the EGR system is operating within the parameters set by the manufacturer.
  

Engine Control Unit (ECU) and Sensor Failures
The ECU in the Kobelco SK350LC-10 controls the emissions systems, including the DPF, SCR, and EGR. If the ECU malfunctions or receives incorrect input from the sensors, it may trigger emissions faults. Common ECU issues can include faulty sensors, such as temperature, pressure, or oxygen sensors, which are vital for the proper operation of the emissions systems.
Symptoms of ECU or sensor failure include:

• Persistent warning lights indicating emissions issues
  
• Erratic engine performance or loss of power
  
• Inconsistent readings on the machine’s diagnostic screen
  

Solution:

• Perform a thorough diagnostic check using specialized software to detect sensor malfunctions.
  
• Replace any faulty sensors or the ECU if necessary.
  
• Reset the ECU to clear any erroneous fault codes.
  

Troubleshooting Process for Emissions Faults

1. Check for Fault Codes: The first step in diagnosing emissions faults in the Kobelco SK350LC-10 is to check the machine’s diagnostic system for any stored fault codes. Use the diagnostic tool to identify whether the fault is related to the DPF, SCR, EGR, or the ECU.
   
2. Inspect Emissions Components: Once a fault code is identified, inspect the relevant emissions components for any visible signs of damage or wear. This includes checking the DPF for soot buildup, the SCR for injector issues, and the EGR system for clogs.
   
3. Perform System Regeneration: If the fault is related to the DPF, attempt a forced regeneration to clear any soot buildup. If the SCR system is malfunctioning, check the urea solution and ensure the injectors are clean and functioning properly.
   
4. Test the Sensors and ECU: If no physical damage is found in the emissions components, check the sensors and ECU. Use diagnostic tools to test the sensors for correct operation and replace any faulty components.
   
5. Reset Fault Codes: After resolving the issue, reset the fault codes in the ECU and test the machine to ensure it is operating correctly.
   

Maintenance Tips for Preventing Emissions Faults
Preventative maintenance is key to avoiding emissions-related problems in the Kobelco SK350LC-10. By staying on top of routine maintenance and addressing issues as they arise, operators can keep their machines running smoothly and efficiently.

• Regularly check DPF condition: Perform periodic cleaning or regeneration of the DPF to prevent clogging.
  
• Use quality urea solution: Ensure that the correct concentration of urea solution is used in the SCR system.
  
• Monitor exhaust temperatures: Excessively high exhaust temperatures can indicate a problem with the SCR or DPF systems.
  
• Clean the EGR system: Periodically clean the EGR valve and cooler to prevent carbon buildup.
  
• Use proper fuel and oils: Always use the manufacturer-recommended fuel and lubricants to reduce the risk of damage to emissions systems.
  

Conclusion
The Komatsu SK350LC-10, with its Hino engine and advanced emissions systems, offers excellent performance and fuel efficiency. However, the complexity of these systems means that emissions faults can occur if proper maintenance is not carried out. By regularly checking components such as the DPF, SCR, and EGR system, and addressing faults early, operators can ensure that their machine continues to operate smoothly and in compliance with emissions standards. Understanding the troubleshooting process and implementing best maintenance practices will help keep the Kobelco SK350LC-10 running efficiently for years to come.