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Diesel Diagnosis (DDS)

Diesel Diagnosis Systems (DDS)

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Basics of Combustion Process Analysis

The modern combustion engine is a highly efficient, high performance machine. The Working Process characteristics depend on the quality of the combustion process inside the cylinders. Combustion Monitoring enables the operator to control the engine so that it runs under the best technical conditions.

What does the Monitoring System give to you?

By using the monitoring system, the operator will be able to:

  • Tune the engine for better performance, efficiency and pollution control, as the system presents tuning advice.
  • Avoid shutdown and emergency repair, as the system automatically protects the engine against dynamic and temperature overload.
  • Predict and schedule necessary maintenance, as the system tracks the engine’s work history.

Cylinder Working Process Parameter Definitions

Figure 2.1

What does the Monitoring System measure?

The Monitoring System initially takes 3 Fundamental Measurements (Figure 2.1):

  • Crankshaft position
  • Cylinder Gas Pressure
  • Fuel Pump or Injector Vibration

What does the Monitoring System calculate?

The system applies Combustion principles and derives all other relevant Working Process Parameters:

Parameter Symbol Unit of Measure
Engine Speed RPM 1/sec
Mean Indicator Pressure Pind Mpa
Cylinder and Engine Power Nind kWt
Maximum Combustion Pressure Pmax MPa
Compression Pressure Pc MPa
Start Injection Tinj dgr
Start Ignition Pign/Tign MPa/dgr

How does the system translate the cylinder pressure into Advice and Alerts?

  • The Measurement sub-System measures the Gas Pressure inside the cylinders. (Figure 2.1)
  • The Processor sub-System calculates the engine parameters such as Power, Maximum Combustion Pressure, etc. (Table 2.1, column 1)
  • The Analysis sub-System compares the calculated parameter values with preset limitations. (Table 2.1, column 2)
  • The Messaging sub-System sends Alerts about the current conditions and gives Advice for engine loading and tune-up. (Table 2.1, column 4)

Example of Engine Working Process Parameter’s Translation   Table 2.1

Parameter (Symbol) Above (+) Below (-) Preset Limit Conditions System Advice Unfollowed Advice Leads To
1 2 3 4 5
Engine Power (Nind) + Engine Overload Slow Down Emergency Stop
Cylinder Power (Nind) + Cylinder Overload Reduce Fuel Portion Emergency Stop
  + / -- Cylinder Power Distribution Imbalance Adjust Cylinder Fuel Portion Engine Power Limitation andHigh Vibration Level
Engine Speed  (RPM) + Engine Over Speed  Slow Down Emergency Stop
  - Engine Overload due to External Resistance Slow Down Emergency Stop
Mean Indicator Pressure (Pind) - Poor Overall Combustion Process Quality Engine Tune-up required Increased Fuel Consumption
MaximumCombustion Pressure (Pmax) + Cylinder Head Damage Late Injection Emergency Stop
  -   Early Injection Increased Fuel Consumption
Compression Pressure (Pc) - Cylinder Parts Degraded Cylinder Repair needed Increased Fuel Consumption
  - Turbo Charging System Degraded Turbo Charger Repair needed Engine Overheating
Dynamic  Pressure (Pmax - Pign) + Crankshaft Damage Late Injection Emergency Stop
Ignition Delay  (Tign - Tinj) + Poor Fuel orFuel Equipment Damage Fuel Equipment Repair Increased Fuel Consumption