18.104.22.168 The following simplified test and measurement procedure specified in this section shall be applied only for on-board confirmation tests and periodical and intermediate surveys when required. Every first engine testing on a test bed shall be carried out in accordance with the procedure specified in chapter 5 using a DM-grade marine diesel fuel. Corrections for ambient air temperature and humidity in accordance with 5.12.3 are essential as ships are sailing in cold/hot and dry/humid climates, which may cause a difference in NOX emissions.
22.214.171.124 To gain meaningful results for on-board confirmation tests and on-board periodical and intermediate surveys, as an absolute minimum, the gaseous emission concentrations of NOX , together with O2
and CO, shall be measured in accordance with the appropriate test cycle. The weighting factors (WF
) and the number of modes (n) used in the calculation shall be in accordance with 3.2.
126.96.36.199 The engine torque and engine speed shall be measured but, to simplify the procedure, the permissible deviations of instruments (see 6.3.7) for measurement of engine-related parameters for on board verification purposes is different than from those permissible deviations allowed under the test bed testing method. If it is difficult to measure the torque directly, the brake power may be estimated by any other means recommended by the engine manufacturer and approved by the Administration.
188.8.131.52 In practical cases, it is often impossible to measure the fuel consumption once an engine has been installed on board a ship. To simplify the procedure on board, the results of the measurement of the fuel consumption from an engine's pre-certification test bed testing may be accepted. In such cases, especially concerning heavy fuel operation, an estimation with a corresponding estimated error shall be made. Since the oil fuel flow rate used in the calculation ( GFUEL
) must relate to the oil fuel composition determined in respect of the fuel sample drawn during the test, the measurement of GFUEL
from the test bed testing shall be corrected for any difference in net calorific values between the test bed and test oil fuels. The consequences of such an error on the final emissions shall be calculated and reported with the results of the emission measurement.
184.108.40.206 Except as otherwise specified, all results of measurements, test data or calculations required by this chapter shall be recorded in the engine's test report in accordance with 5.10.
6.3.2Engine parameters to be measured and recorded
Table 6 lists the engine parameters that shall be measured and recorded during on-board verification procedures.
Table 6. Engine parameters to be measured and recorded
|bx,i||specific fuel consumption (if possible) (at the ith mode during the cycle)||kg/kW h|
|Ha||absolute humidity (mass of engine intake air water content related to mass of dry air)||g/kg|
|nd,i ||engine speed (at the ith mode during the cycle)||min-1|
|nturb,i||turbocharger speed (if applicable)(at the ith mode during the cycle)||min-1|
|pB||total barometric pressure (in ISO 3046-1, 1995: px = PX = site ambient total pressure)||kPa|
|pbe,i||air pressure after the charge air cooler (at the ith mode during the cycle)||kPa|
|Pi||brake power (at the i th mode during the cycle) ||kW|
|si||fuel rack position (of each cylinder, if applicable)(at the ith mode during the cycle)|
|Ta||temperature at air inlet (in ISO 3046-1, 1995: Tx = TTX = site ambient thermodynamic air temperature)||K|
|Tba,i||air temperature after the charge air cooler (if applicable)(at the ith mode during the cycle)||K|
|Tclin||Coolant temperature inlet ||K|
|Tclout||Coolant temperature outlet ||K|
|TExh,i||Exhaust Gas Temperature at the sampling point(at the ith mode during the cycle)||K|
|TFuel||Fuel oil temperature before the engine ||K|
|Tsea||Sea water temperature ||K|
|Toil out/in||Lubricating oil temperature, outlet/inlet ||K|
220.127.116.11 The point regarding the ability to obtain the required data during on-board NOX testing is particularly relevant to brake power. Although the case of directly coupled gearboxes is considered in chapter 5, the engines, as may be presented on board, could in many applications, be arranged such that the measurements of torque (as obtained from a specially installed strain gauge) may not be possible due to the absence of a clear shaft. Principal in this group would be generators, but engines may also be coupled to pumps. hydraulic units. compressors, etc.
18.104.22.168 The engines driving such machinery would typically have been tested against a water brake at the manufacture stage prior to the permanent connection of the power consuming unit when installed on board. For generators this should not pose a problem to use voltage and amperage measurements together with a manufacturer's declared generator efficiency. For propeller law governed equipment, a declared speed power curve may be applied together with ensured capability to measure engine speed, either from the free end or by ratio of, for example, the camshaft speed.
22.214.171.124 Generally all emission measurements shall be carried out with the engine running on marine diesel fuel oil of an ISO 8217, 1996, DM-grade.
126.96.36.199 To avoid an unacceptable burden to the shipowner, the measurements for confirmation tests or re-surveys may, based on the recommendation of the engine manufacturer and the approval of the Administration, be allowed with an engine running on heavy fuel oil of an ISO 8217, 1996, RM-grade. In such a case the fuel bound nitrogen and the ignition quality of the fuel may have an influence on the NOX emissions of the engine.
6.3.5Sampling for gaseous emissions
188.8.131.52 The general requirements described in 5.9.3 shall be applied for on-board measurements as well.
184.108.40.206 The installation on board of all engines shall be such that these tests may be performed safely and with minimal interference to the engine. Adequate arrangements for the sampling of the exhaust gas and the ability to obtain the required data shall be provided on board a ship. The uptakes of all engines shall be fitted with an accessible standard sampling point.
6.3.6Measurement equipment and data to be measured
The emission of gaseous pollutants shall be measured by the methods described in chapter 5.
6.3.7Permissible deviation of instruments for engine related parameters and other essential parameters
Tables 3 and 4 contained in paragraph 1.3.2 of appendix 4 of this Code list the permissible deviation of instruments to be used in the measurement of engine-related parameters and other essential parameters during on-board verification procedures.
6.3.8Determination of the gaseous components
The analytical measuring equipment and the methods described in chapter 5 shall be applied.
220.127.116.11 Test cycles used on board shall conform to the applicable test cycles specified in 3.2.
18.104.22.168 Engine operation on board under a test cycle specified in 3.2 may not always be possible, but the test procedure shall, based on the recommendation of the engine manufacturer and approval by the Administration, be as close as possible to the procedure defined in 3.2. Therefore, values measured in this case may not be directly comparable with test bed results because measured values are very much dependent on the test cycles.
22.214.171.124 If the number of measuring points on board is different than those on the test bed, the measuring points and the weighting factors shall be in accordance with the recommendations of the engine manufacturer and approved by the Administration.
6.3.10Calculation of gaseous emissions
The calculation procedure specified in chapter 5 shall be applied, taking into account the special requirements of this simplified measurement procedure.
126.96.36.199 Due to the possible deviations when applying the simplified measurement procedures of this chapter on board a ship, an allowance of 10% of the applicable limit value may be accepted for confirmation tests and periodical and intermediate surveys only.
188.8.131.52 The NOX emission of an engine may vary depending on the ignition quality of the fuel and the fuel bound nitrogen. If there is insufficient information available on the influence of the ignition quality on the NOX formation during the combustion process and the fuel bound nitrogen conversion rate also depends on the engine efficiency, an allowance of 10% may be granted for an on-board test run carried out on a RM-grade fuel (ISO 8217, 1996) except that there will be no allowance for the pre-certification test on board. The fuel oil used shall be analysed for its composition of carbon, hydrogen, nitrogen, sulphur and, to the extent given in ISO 8217, 1996, any additional components necessary for a clear specification of the fuel.
184.108.40.206 In no case shall the total granted allowance for both the simplification of measurements on board and the use of heavy fuel oil of an ISO 8217, 1996, RM-grade fuel, exceed 15% of the applicable limit value.