INVESTIGATION AND CAUSE OF ENGINE BLACK SMOKING

INVESTIGATION AND CAUSE OF ENGINE BLACK SMOKING

When we start investigating this situation due to drifting of wind from one  exhaust pipe over another causing difficulty in locating which engine is smoking  if offending engine is identified then again it is trouble to identify which unit is faulty or the whole unit is faulty .

 Plug or Cocks of exhaust elbow leading to manifold should opened individually and  condition of exhaust gas should be examined with the help of   light reflecting surface . If all the cylinders are found to be smoky then following points to be checked as given below -

1. Engines operating on heavy fuel oil hence fuel TEMPERATURE is checked and correction is made if necessary because we require proper viscosity to the fuel pump , injector and to the combustion space (around 13 cst for HFO to the  fuel injector).
2. If temperature is correct then  check the RPM of the blower in case of supercharging system.  
3. If scavenging pressure is high means scavenging port has fouled or there is fouling of air filter of the compression side of turbocharger .
4. INDICATOR CARD (LIGHT SPRING CARD) is taken to ensure the variation of scavenging air and exhaust gas if the engine is not having indicator cock then temporary remove the air filter and check the condition of the exhaust.

If a single unit is SMOKY it is usually due to dirtiness of INJECTOR (FUEL VALVE) ,if it has changed then monitor the condition of FUEL PUMP DELIVERY PRESSURE , EXHAUST TEMPERATURE, MAXIMUM FIRING PRESSURE. if every thing is normal then take DRAW CARD (out of phase diagram ), COMPRESSION CARD so that the compression pressure and maximum pressure can be found .

In case injector is to be checked for leakage, setting pressure and lift . Condition of spray holes , diameter and holes edges should be examined and overhauled otherwise it can be possible cause of black smoking.