 MAN B&W Diesel A/S holds a leading position world wide in diesel engine technology. With a view to consolidating this position, the company invests substantial amounts in diesel engine technology R&D. The P/M HIP fuel nozzle is an example of that work.
The P/M HIP nozzle gives superior engineering properties, compared with the former cast stellite version.
The Metal Powder Industries Federation (MPIF) awarded the nozzle the grand prize in the overseas category in the 1999 Powder Metallurgy Design Competition.
Diesel engines run at 94-104 rpm in tankers, large container ships and fishing trawlers, and in land-based electric power generation installations. The nozzle, weighing only about 100 g, atomizes 120°C heavy fuel oil injected by fuel valves at an injection pressure of 600-800 bars. The maximum surface temperature of the nozzle during operation is 500-650°C. Three fuel valves are mounted on the cylinder head.
The P/M alloy microstructure has a fine grain size with a very low level of non-metallic inclusions. This is required for adequate fatigue life at high operating temperatures while maintaining high temperature corrosion resistance.
For MAN B&W, the P/M HIP fuel nozzle is an outstanding part because:
- The increased mechanical properties (fatigue limit) allow for a special design with improved combustion control.
- The improved Hot Corrosion-resistance allows for a shorter mounting distance between fuel valves (which means a higher heat load on the nozzle tip). As a consequence, it is possible to place three fuel valves per cylinder head instead of two, resulting in a more even heat distribution and reduced heat load of the combustion chamber components facilitating high reliability.
- The improved machinability of the P/M nozzle assures reproducibility of close dimensional tolerances and geometrical requirements, which are vital for the performance of the nozzle.
- The outstanding wear resistance of the P/M material ensures that close tolerances and dimensional requirements will be maintained during an increased lifetime of the nozzle.
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