4.3.8.3 If there are engines, which incorporate other features which could be considered to affect NOx exhaust emissions, these features must be identified and taken into account in the selection of the engines to be included in the family.
4.3.9 Guidelines for Selecting the Parent Engine of an Engine Family
4.3.9.1 The method of selection of the parent engine for NOx measurement shall be agreed to and approved by the Administration. The method shall be based upon selecting an engine which incorporates engine features and characteristics which, from experience, are known to produce the highest NOx emission expressed in grammes per kilowatt hour (g/k Wh). This requires detailed knowledge of the engines within the family. The option of choosing more than one engine to represent the family may be considered.
4.3.9.2 The following criteria for selecting the parent engine for NOx emission control shall be considered, but the selection process must take into account the combination of basic characteristics in the engine specification:
.1 main selection criteria
- higher fuel delivery rate
.2 supplementary selection criteria
- higher mean effective pressure
- higher maximum cylinder peak pressure
- higher charge air/ignition pressure ratio
- dp/dα, the lower slope of the combustion curve
- higher charge air pressure
- higher charge air temperature
4.3.9.3 If engines within the family incorporate other variable features which may affect the NOx emissions, these feature must also be identified and taken into account in the selection of the parent engine.
4.3.10Certification of an Engine Family
4.3.10.1 The certification shall include a list, to be prepared and maintained by the engine manufacturer and approved by the Administration, of all engines and their specifications accepted under the same engine family, the limits of their operating conditions and the details and limits of engine adjustments that may he permitted.
4.3.10.2 A pre-certificate, or EIAPP Certificate, should be issued for a member engine of an entire family in accordance with this Code which certifies that the parent engine meets the NOx levels specified in regulation 13 of Annex VI.
4.3.10.3 When the parent engine of art engine family is tested/measured under the most adverse conditions specified within this Code and confirmed as complying with the maximum allowable emission limits (see 3.1), the results of the test and NOx measurement shall be prescribed
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ANNEX
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in the EIAPP Certificate issued fur the particular parent engine and for all member engines of the engine Cannily.
4.3.10.4 If two or more Administrations agree to accept each other's EIAPP's, then an entire engine family, certified by one of these Administrations, shall be accepted by the other Administrations which entered into that agreement with the original certifying Administration.
Certificates issued under such agreements shall be acceptable as prima facie evidence that all engines included in the certification of the engine family comply with the specific NOx emission requirements. There is no need for further evidence of compliance with regulation 13 of Annex VI if it is verified that the installed engine has nut been modified and the engine adjustment is within the range permitted in the engine family certification.
4.3.10.5 An Administration may approach another Administration that issued an engine certificate and request further information if there is reason to question the validity of the issuing Administration 's certification process or whether an engine was in compliance at the time of certificate issuance. If an Administration can demonstrate to the satisfaction of the International Maritime Organization (IMO) than another Administration is not following the procedures outlined in this Code, then the Administration may be notified of non-acceptance of new certificates.
4.3.10.6 If the parent engine of an engine family is so be certified in accordance with an alternative standard or a different test cycle than allowed by shin Code, the manufacturer must prove to the Administration that the weighted average NOx emissions for the appropriate test cycles fall within the relevant limit values under regulation 13 of Annex VI and thin Code before the Administration may issue an HAPP Certificate.
4.3.10.7 A model form of an EIAPP Certificate is attached as appendix 1 to this Code.
4.4 APPLICATION OF THE ENGINE GROUP CONCEPT
4.4.1 These are engines used primarily for main propulsion. They normally require adjustment or modification to suit the on-board operating conditions but which should not result in NOx emissions exceeding the limits in 3.1 of this Code.
4.4.2 The engine group concept also provides the possibility for a reduction in approval tenting for modifications no engines in production or in service.
4.4.3 In general, the engine group concept may be applied to any engine type having the same design features as specified in 4.4.5. but individual engine adjustment or modification after test bed measurement is allowed. The range of engines in an engine group and choice of parent engine shall be agreed so and approved by the Administration.
4.4.4 The application for the engine group concept, if requested by the engine manufacturer another party, shall be considered for certification approval by the Administration. If the engine owner, with or without technical support from the engine manufacturer, decides to perform modifications on a number of similar engines in the owner's fleet, the owner may apply for an engine group certification. The engine group may include a teat engine on the tens bench. Typical applications are similar modifications of similar engines in service or similar engines in similar operational conditions.
