5.2.1
Test condition parameter and test validity for engine family approval
5.2.1.1 The absolute temperature Ta of
the engine intake air expressed in Kelvin shall be measured, and the
dry atmospheric pressure p
s, expressed in
kPa, shall be measured or calculated as follows:
- p
a according to formula (10)
5.2.1.2 For naturally aspirated and mechanically pressure
charged engines operating on liquid or dual fuel the parameter f
a shall be determined according to the following:
5.2.1.3.1 For turbocharged engines operating on liquid or
dual fuel with or without cooling of the intake air the parameter fa
shall be determined according to the following:
5.2.1.3.2 For engines to be tested with gas fuel only with
or without cooling of the intake air the parameter fa shall be
determined according to the following:
5.2.1.4 For a test to be recognized as valid for engine
family approval, the parameter fa shall be such that:
5.2.2
Engines with charge air cooling
5.2.2.1 The temperature of the cooling medium and the
charge air temperature shall be recorded.
5.2.2.2 All engines when equipped as intended for
installation on board ships must be capable of operating within the applicable
NOx emission limit of regulation 13 at
an ambient seawater temperature of 25°C. This reference temperature shall be considered
in accordance with the charge air cooling arrangement applicable to the individual
installation as follows:
-
.1 Direct seawater cooling to engine charge air
coolers. Compliance with the applicable NOx limit shall be demonstrated
with a charge air cooler coolant inlet temperature of 25°C.
-
.2 Intermediate freshwater cooling to engine charge
air coolers. Compliance with the applicable NOx limit shall be
demonstrated with the charge air cooling system operating with the designed in
service coolant inlet temperature regime corresponding to an ambient seawater
temperature of 25°C.
-
Note:
Demonstration of compliance at a parent engine test for a direct seawater
cooled system, as given by (.1) above, does not demonstrate compliance in
accordance with the higher charge air temperature regime inherent with an
intermediate freshwater cooling arrangement as required by this section.
-
.3 For those installations incorporating no seawater
cooling, either direct or indirect, to the charge air coolers, e.g.,
radiator-cooled freshwater systems, air/air charge air coolers, compliance with
the applicable NOx limit shall be demonstrated with the engine and
charge air cooling systems operating as specified by the manufacturer with 25°C
air temperature.
5.2.2.3 Compliance with the applicable NOx
emission limit as defined by regulation 13 shall be demonstrated either by testing or by
calculation using the charge air reference temperatures (TSCRef) specified
and justified by the manufacturer, if applicable.
5.2.3.1 The basis of specific emissions measurement is
uncorrected brake power as defined in 1.3.11 and
1.3.13.The engine shall be submitted with auxiliaries needed for operating the
engine (e.g., fan, water pump, etc.). If it is impossible or inappropriate to install
the auxiliaries on the test bench, the power absorbed by them shall be determined and
subtracted from the measured engine power.
5.2.3.2 Auxiliaries not necessary for the operation of the
engine and that may be mounted on the engine may be removed for the test. See also 5.1.5 and 5.1.6.
5.2.3.3 Where auxiliaries have not been removed, the power
absorbed by them at the test speeds shall be determined in order to calculate the
dynamometer settings, except for engines where such auxiliaries form an integral part of
the engine (e.g., cooling fans for air cooled engines).
5.2.4
Engine air inlet system
5.2.4.1 An engine air intake system or a test shop system
shall be used presenting an air intake restriction within ± 300 Pa of the maximum value
specified by the manufacturer for a clean air cleaner at the speed of rated power and
full-load.
5.2.4.2 If the engine is equipped with an integral air
inlet system, it shall be used for testing.
5.2.5
Engine exhaust system
5.2.5.1 An engine exhaust system or a test shop system
shall be used that presents an exhaust backpressure within ± 650 Pa of the maximum value
specified by the manufacturer at the speed of rated power and full load. The exhaust
system shall conform to the requirements for exhaust gas sampling, as set out in 5.9.3.
5.2.5.2 If the engine is equipped with an integral exhaust
system, it shall be used for testing.
5.2.5.3 If the engine is equipped with an exhaust
after-treatment device, the exhaust pipe shall have the same diameter as found in-use
for at least 4 pipe diameters upstream to the inlet of the beginning of the expansion
section containing the after-treatment device. The distance from the exhaust manifold
flange or turbocharger outlet to the exhaust after-treatment device shall be the same as
in the onboard configuration or within the distance specifications of the manufacturer.
The exhaust backpressure or restriction shall follow the same criteria as above, and may
be set with a valve.
5.2.5.4 Where test-bed installation prevents adjustment to
the exhaust gas backpressure as required, the effect on the NOx emissions
shall be demonstrated by the engine builder and, with the approval of the
Administration, the emission value duly corrected as necessary.
5.2.6.1 An engine cooling system with sufficient capacity
to maintain the engine at normal operating temperatures prescribed by the manufacturer
shall be used.