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Steadily rising fuel prices are forcing ship operators and power plants to optimize their energy costs and keep them low. In the medium and long term, it is expected that fuel prices will increase and carbon di-oxide emission allowances will be introduced.
In addition to energy-saving initiatives on vessels, such as low-energy lighting and hull coating, significantly lower fuel consumption potential can be found in diesel engines. But due to a lack of appropriate monitoring devices this has not yet been realized.
Only a high-precision power balance allows controlled fuel savings. International Technology has ushered a new era of online multi-cylinder engine-monitoring systems for portable and permanent installations. For the first time, these systems can provide a power balance on diesel and gas engines with very high accuracy. They replace conventional measurement methods with single-cylinder systems known as peak meters.
New multi-cylinder online monitoring systems, such as DocHub e-932 and previously the DM 8-32 as well as the fixed online system DM 10-TP determine in real time and with high precision the exact performance differences between the cylinders in one cycle.
Such differences are caused if the cylinders brake against each other, which means that the engine is not perfectly balanced and this leads to a significant increase in fuel consumption. Crucial to this issue is Det Norske Veritas’ guidance, which states: “1% difference in performance is 1% higher fuel consumption.”
The efficiency of the new system has been proven on vessels of well-known cruise companies and container vessels with very effective power balancing. As expected, the multi-cylinder online monitoring systems identified additional fuel savings of up to 3%.
The test was performed on several cruise ships and container vessels having different two and four-stroke engines with 8 to 16 cylinders which had previously been monitored with the conventional peak-meter method. The average fuel savings on each ship accounted to five to seven tones of heavy fuel oil per day. This represents significant savings of between USD 700,000 and 1.2 million per ship per year, depending on engine performance and engine use.
The above test example shows a very effective power-balancing of a Wärtsilä 12V46CR engine with common rail injection.