Although the technical code includes the checking procedures for both of the periodic survey and the intermediate survey, it does not include the definitions for the period between the periodic or intermediate survey and 30 days before the next survey.

　

Therefore in this technical code the definitions on NOx monitoring should be also limited for the periodic and intermediate surveys.

　

If necessary, the definitions on NOx monitoring for the period between the periodic or intermediate survey and 30 days before the next survey shall be investigated separately as additional items of the technical code.

　

　

1.	USA proposes the measurement at transient load as well. And USA insists the experiences on the land generating diesel engines will be effective for the measurement. However the actual situation on shipboard is not taken into considerations. The accurate measurement of output of engine at transient load is very difficult. And exact correspondence between varying load and measured NOx concentration is also difficult. Although it is certain both of load and NOx are measurable, it is nonsense to acquire data that cannot be related to each other.
2.	Annex VI as well as Technical Code and the proposal by USA seems to be the regulation for the regulation, and the actual situation on shipboard especially in service is not considered. If the convention is ratified, ships must continuously be kept its compliance with regulation for 15〜20 years. Consequently possible deterioration due to aging and the influences of season shall be considered.
3.	Under the condition the load is stable, NOx measurement can be thought to be practical technically. The greatest concern is how the measured data is dealt with. NOx emission that is determined by continuous monitoring method should at least be adjusted to an equivalent level to the measured value on the pre-certification survey or the initial survey. Consequently the influences of the following factors should be investigated sufficiently.

	・	Allowance of the applicable limit for NOx emission determined by continuous monitoring method
	・	Differences from the situation at the pre-certification survey or the initial survey
	・	Deterioration due to aging
	・	Fuel oil quality
	・	Season(temperature, humidity), ship route, kind of ship

4.	Regarding continuous NOx monitoring on board a ship, no technical verification on the following items has been done yet.

	・	Dealing with ambient condition and engine load
	・	Converting of the fuel bound nitrogen
	・	Reliability of the monitoring and recording devices

　

Therefore realistic long-term investigation on board a ship shall be necessary. Japan will proceed an on-board NOx monitoring test and an investigation of influences of fuel bound nitrogen on NOx emission for 2 years. Based on the results, Japan will propose the establishment of realistic specification for continuous monitoring.

　

　

Paragraph 6.4　- Direct measurement and monitoring method

　

6.4.1　General

　

6.4.1.1　Conditions for application

The direct measurement and monitoring method specified in this section shall be applied only for periodical and intermediate surveys when required. Corrections for ambient air temperature and humidity in accordance with the requirements in 5.12.3 are essential as ships are sailing in cold/hot and dry/humid climates, which may cause a difference in NOx emissions.

　

6.4.1.2　Monitoring and recording devices

Monitoring and recording devices, including the specifications, calibrations and method to ensure that the reliability of monitoring data is maintained during services, shall be complied with the requirements in the Guidelines for on-board NOx monitoring and recording devices based on the requirements in 2.4.5.

　

6.4.1.3　Engine load/interval for data sampling

The data for certification survey shall be taken at the most frequently operated load (one point) and for at least 30 minutes continuously. And the data shall be taken at least 5 times for the period within 30 days before the periodical or intermediate surveys. However, where there is special reason that the data cannot be taken within this 30 days, the data within 6 months may be accepted.

　

(Basic concept to Regulation 6.4.1.3)

　

The draft for NOx monitoring method useful for the rest of the above mentioned period is proposed below.

　

As a premise, it is necessary to confirm the development of the practical sensors (monitoring system). The following proposal is considered.

　

6.4.1.4　Monitoring records

The monitoring records shall be kept on board until the completion of periodical or intermediate surveys for the verification.

　

6.4.2　Analysis of the fuel

　

6.4.2.1　The sample of the fuel used for the direct measurement and monitoring method shall be analysed. The sample shall be kept on board until the completion of the periodical or intermediate surveys for the verification. The fuel sampling position is to be at a service tank or the down stream. The fuel sampling is to be carried out during the NOx measurement.

　

6.4.2.2　As the result of the fuel analysis, the value, N is to be added to the Bunkering Delivery Note. Where the blending fuel oil is used, the greater value is to be used.

　

6.4.3　Items to be measured

The exhaust components to be measured shall be NOx, O2, temperature and humidity of intake air. The necessary data such as exhaust flow and engine load etc, may be measured or estimated by the means recommended by the engine manufacturer and approved by the Administration. NOx value shall be corrected for intake air temperature and humidity by the appropriate formula.

　

6.4.4　Sampling for gaseous emissions

　

6.4.4.1　Sampling method of gaseous emissions

The sample for the exhaust components to be measured may be taken with one sampling probe or with two sampling probes located in close proximity. Care must be taken that no condensation of the exhaust components (including water and sulphuric acid) occurs at any point of the analytic system.

　

6.4.4.2　If the composition of the exhaust gas is influenced by any exhaust after treatment system, the exhaust sample must be taken downstream of this device.

　

6.4.5　Evaluation criteria

The monitoring and recording data shall be evaluated considering the data of engine's first certification survey (test data to be complied with the Chapter 5 in this code.) or the test data of the on board simplified measurement (if any). The fuel NOx shall be considered and the allowable limits by the code are to be adjusted according to the Nitrogen contents in the fuel.

(Note: It is to be determined by the result of the demonstration test (by Japan) relating to the NOx caused by the fuel.)

　

(Basic Concept to Regulation 6.4.5)

　

The draft for details of the evaluation is proposed below.

　

The graph like a following in which relation between engine load and NOx quantity in the exhaust gas is proven is to be made at the manufacturer's test bed testing. Based upon the value of the graph, the allowance of the NOx limit of the onboard test is to be determined taking into consideration of the allowable error caused by the environmental condition, fuel condition, measurement error etc.