Answer
NOx measurement methods:-
1. Engine parameter method
2. Simplified measurement method
3. Direct measurement method
Among these methods engine parameter method is widely used.
Onboard verification includes:-
1.Review of all engine certificates (EIPPC) and NOx technical file and ensuring these are approved.
2.To verify “engine parameter book” for each engine exist and they are updated.
3.Relevant entries are correctly completed. It shall contain records of work carried out on the engine, such as modification, setting of adjustments, components replacement which are properly entered and signed either by chief engg or 2nd engineer or manufacturer’s representative with appropriate date.
4.To verify any modification, adjustments or replaced parts confirm to engine specification and parameters in NOx technical file.
5.Verify data logging systems are operational and records are current.
6.Review engine data for trends, which may indicate possible engine problems relating to NOx emission noncompliance.
7.Verify the engine components and settings are as detailed in NOx technical file i.e. no modification or adjustments have been made other than approved by a survey in accordance with on board engine verification method specified in the approved NOx technical file for the engine.
8.If fitted, the direct NOx reduction method, calibration is verified, and operation in accordance to manufacturer’s. Same applies to exhaust cleaning or other NOx reduction system if they are fitted.
ENGINE is NOx compliant Can be verified by // Applicable NOx limit can be verified by: :-
·Engine Name Plate
·NOx Tech. File
·IAPP Certificate (Contains only Applicable e TIER but not NOx value)
·EIAPP Certificate
PARAMETERS MEASURED FOR NOX CALCULATION / NOX PARAMETERS FROM LOGBOOK
The table 1 shows a list of the measured standard performance parameters at testbed. And the allowable ranges for some of the parameters are given in Chapter D.
Table 1. Measured Performance Parameaters at testbed
·Rated power (kW)
·Rated speed (rpm)
·Mean effective pressure (bar)
·Cylinder maximum pressure (bar)
·Fuel injection timing (deg. CA LTDC)
·Fuel consumption (kg/h)
·Turbocharger speed (rpm)
·Exhaust g as temperature after Turbocharger (C).
·Exhaust g as flow (kg/h) * *
·Air consumption (kg/h) * *
·Exhaust g as emissions - Exhaust gas back pressure (mmWC)
·Atmospheric pressure (kPa) - Intake air humidity (%) - Intake air temperature (°C)
·Charge air pressure (kg/cm)
·Charge air temperature (°C) ,
·Charge air cooling water inlet/outlet te emperature (°C)
·Fuel oil inlet temperature (°C)