General Classification Rules
All marine engines shall have type approval certificate, i.e. the engine design is approved through a thorough type approval scheme including approval of drawings, data, specifications, calculation and other information specified in DNV-RU SHIP Pt.4 Ch.3 Sec.1. In addition, propulsion engines with rated power of 300 kW or above shall have product certificates issued by classification society. Turbochargers serving cylinder groups with rated power above 2500 kW shall have their own product certificates. For turbochargers serving power between 1000 kw and 2500 kW a product declaration is sufficient. // DNV-RU SHIP Pt.4 Ch.3 Sec.1.1 and Pt.4 Ch.3 Sec.1.11.1
The engines are through a thorough testing process both during the type approval and individually before getting product certificates. The test result for individual engines including alarm settings and testbed data at 110%, 100%, 90%, 75%, 50% and 25% load and are available on the engine manual for future monitoring of the engines. After installation onboard the engines shall also undergo a set of dock and sea trials. // DNV-RU SHIP Pt.4 Ch.3 Sec.1.4 and PT.4 Ch.3 Sec.1.9
Engines shall be designed such that their rated power when running at rated speed can be delivered as a continuous power. The maximum continuous power shall be specified in such a way that an overload power of 110% of the rated power can be achieved. Engines with cylinder bore of 200 mm or more shall be equipped with crankcase safety valves. Airing of crankcases and any arrangement which could produce air intake within the crankcase are not allowed excluding oil mist detectors. Engines shall be equipped with suitable self-locking type turning appliances, with an automatic interlock device ensuring that engine cannot start up while the turning gear is engaged.
Maximum allowed surface temperature on engines is 220 ⁰C. Surfaces which might reach higher temperatures shall be insulated with materials that have non-oil-absorbing surface or be equivalently protected so that flammable fluid spray potentially reaching the surfaces cannot be ignited. All pipe connections on fuel and lube oil piping with pressure above 1.8 bars shall be screened to prevent oil leakage or spray onto potentially hot surfaces. Only pipe connections with metal sealing surfaces or equivalent pipe connections of approved design may be used for fuel injection lines. All external high pressure fuel injection lines between injection pumps and injection valves shall be screened by jacket pipes in such a way, that any leaking fuel is safely collected and drained away unpressurized. A fuel oil leakage shall be drained efficiently, and the design shall be such that a fuel oil leakage cannot en-ter the engine lubrication oil system. There shall be an alarm upon fuel oil leakage. // DNV-RU SHIP Pt.4 Ch.3 Sec.1.2.6 and Pt.4 Ch.3 Sec.1.2.8
Means for regulating the charge air temperature, typically charge air cooler, shall be provided. Charge air lines and coolers shall be equipped with sufficient means of drainage. Turbochargers shall not exhibit critical speed ranges over the entire operating range of engine. The lubrication oil supply for turbochargers shall be ensured during start-up and run-down, including emergency conditions where loss of forced lubrication may occur during blackout. Emergency operation of single propulsion engines shall be possible in case of turbocharger failure. // DNV-RU SHIP Pt.4 Ch.3 Sec.1.2.10
Remote control of propulsion machinery shall be possible only from one location at the time. The transfer of control between machinery space and navigation bridge shall be possible only from the engine control room. Local control of propulsion machinery shall be possible in any case of failure of the remote-control system. All parameters triggering slow down or shutdown (excluding overspeed and oil mist) shall be arranged with an alarm occurring first. These alarms shall be indicated also on the bridge whenever the propulsion is controlled from that position. For single propulsion engine an override facility to manually intervene on all slowdowns and shutdowns (excluding low lubrication oil pressure, overspeed, oil mist and short-circuit conditions on electrical installations) shall be available. A complete list of required control and monitoring devices for propulsion engines is available in DNV-RU SHIP Pt.4 Ch.3 Sec.1.5.4 Table 10. There is some variation depending of the type of engine, rated output and intended fuel. For overspeed protection there shall always be two independent protection devices on engines with rated power above 220 kW, i.e. the normal governor and an additional device. // DNV-RU SHIP Pt.4 Ch.3 Sec.1.2.6 and Pt.4 Ch.3 Sec.1.5.3