Cleaner Technology Projects in Denmark 1997

Charting of the Air Pollution of Marine Engines

Kortlægning af marinemotorers luftforurening
Arbejdsrapport nr. 61, 1997, Miljøstyrelsen

Focus on environmental consciousness has spread to the marine-sector. For several years demands for reductions and emissions have been discussed. ISO has been working on standards for how the emissions of motors should be measured and IMO are stating the maximum value for the NOx-emission. This report describes the test and emission measurements that have been made on three marine engines.

The project was carried out by DTI Energi/Motorteknik i co-operation with MAN B & W Diesel A/S, Alpha Diesel (MBD-F) and MAN B & W Diesel A/S, Holeby Diesel (MBD-H).

MBD-F produces propelling motors and MBD-H produces generating motors. There are several technical differences depending on if the motors are used for propellant force or if they are used for generating force. In the report a motor type 28/32 H is measured as a generating motor and motors type 23/30A and type 28/32A are measured as propellant motors.

The emission measurements have been carried out on the three marine engines according to ISO 8178.

Measurements were carried out for three different values of the inlet air temperatures and for the inter-cooled air temperature in order to evaluate their influence on the emission. On this basis it was possible to compare the results with the formulas for NOx correction stated in ISO 8178. The conclusion drawn was that the influence depends on the engine and that the formulas in ISO 8178 are insufficient to compensate for the change.

The reference-measurements show that the IMO- (International Maritime Organisation) requirements concerning the emission of NOx is followed by the measured motors in the standard-versions, but the requirements of EPA (Environmental Protection Agency) about the emission of NOx cannot be kept. The EPA requirements of the CO emissions, HC and particles are kept. The requirements to the marine-sector that can be expected from EPA and from the EU, mean in particular a tightening of the NOx-emission. Single measurements with changed adjustment show that the engines have potential to meet the EPA demand for 1999-2000.

Based on the experience from this project, MAN B&W Diesel A/S, Alpha Diesel decreased the emission from the main engine in a local ferry in the Oslofjord. The main object was to reduce NOx emission without increasing fuel consumption. A NOx reduction of 18 % was achieved, measured and weighed with respect to the ISO 8178 loads without any increase in fuel consumption.

Author/ institution

Flemming Bak og Michael Grouleff Jensen, DTI Energi/ Motorteknik

This report is subsidised by the National Council for Recycling and Cleaner Technology

ISSN no. 0908-9195
ISBN no. 87-7810-850-0