5.3.2 The selection of the fuel for the test depends of the test. Unless otherwise agreed by the Administration and when a suitable reference fuel is not available, a DM-grade marine fuel specified in ISO 8217, 1996, with properties suitable for the engine type shall be used.
5.3.3 The fuel temperature shall be in accordance with the manufacturer's recommendations. The fuel temperature shall be measured at the inlet to the fuel injection pump or as specified by the manufacturer, and the temperature and location of measurement recorded.
5.4 MEASUREMENT EQUIPMENT
5.4.1 The emission of gaseous components the engine submitted for testing shall be measured by the methods as set out in appendix 5 of this Code, which describes the recommended analytical system for the gaseous emissions.
5.4.2 Other systems or analysers may, subject to the approval of the Administration, be accepted if they yield equivalent results to that of the equipment referenced in 5.4.1.
5.4.3 The Code does not contain details of flow, pressure, and temperature measuring equipment. Instead, only the accuracy requirements of such equipment necessary for conducting an emissions test are given in 1.3.1 of appendix 6 of this Code.
5.4.4 Dynamometer specification
5.4.4.1 An engine dynamometer with adequate characteristics to
perform the appropriate test cycle described in 3.2 shall be used.
5.4.4.2 The instrumentation for torque and speed measurement shall allow the measurement of the shaft power over the range of the test bed operations as specified by the manufacturer. If this is not the case, then additional calculations shall be required and recorded..
5.4.4.3 The accuracy of the measuring equipment shall be such that the maximum tolerances of the values given in 1.3.1 of appendix 6 of this Code are not exceeded.
5.5 DETERMINATION OF EXHAUST GAS FLOW
The exhaust gas flow shall be determined by one of the methods specified in 5.5.1, 5.5.2. or 5.5.3.
5.5.1 Direct measurement method
This method involves the direct measurement of the exhaust flows by flow nozzle or equivalent metering system and shall be in accordance with a recognized international standard.
Note: Direct gaseous flow measurement is a difficult task. Precaution should be taken to avoid measurement errors which will impact emission value errors.
5.5.2 Air and fuel measurement method
5.5.2.1 The method for determining exhaust flow using the air and fuel measurement method shall be conducted in accordance with a recognized international standard.
MEPC 39/6/1
ANNEX
Page 23
5.5.2.2 Air flowmeters and fuel flowmeters with an accuracy defined in 1.3.1 of appendix 6 of this Code shall be used.
5.5.2.3 The exhaust gas flow shall be calculated as follows:
.1 G EXHW = G AIRW + G FUEL (for wet exhaust mass)(4)
or
.2 V EXHD = V AIRD + F FD･GFUEL (for dry exhaust volume) (5)
or
.3 V EXHW = V AIRW + F FW･G FUEL (for wet exhaust volume) (6)
Note: Values for F FD and F FW vary with the fuel type (see table 1 of appendix 7 of this Code)
5.5.3 Carbon balance method
This method involves exhaust gas mass flow calculation from consumption and exhaust gas concentrations using the carbon and oxygen balance method as specified in appendix 7 of this Code.
5.6 PERMISSIBLE DEVIATIONS OF INSTRUMENTS FOR ENGINE RELATED PARAMETERS AND OTHER ESSENTIAL PARAMETERS
The calibration of all measuring instruments shall be traceable to recognized international standards and shall comply with the requirements as set out in 1.3.1 of appendix 6 of this Code.
5.7 ANALYSERS FOR DETERMINATION OF THE GASEOUS COMPONENTS
The analysers to determine the gaseous components shall meet the specifications as set out in appendix 5 of this Code.
5.8 CALIBRATiON OF THE ANALYTICAL INSTRUMENTS
Each analyser used for the measurement of an engine's parameters, as discussed in appendix 5 of this Code, shall be calibrated as often as necessary as set out in appendix 6 of this Code.
5.9 TEST RUN
5.9.1 General
5.9.1.1 Detailed descriptions of tire recommended sampling and analysing system are contained in 5.9.2 to 5.9.4. Since various configurations may produce equivalent results, exact conformance wish these figures is not required. Additional components, such as instruments, valves, solenoids, pumps, and switches, may be used so provide additional information and coordinate the functions of the component systems. Other components which are not needed so maintain the accuracy on some systems, may be excluded if their exclusion is based upon good engineering judgement.
