Benefits of MAN Marine Engines

Design Principles: MAN marine diesel engines are designed on modular principles. This allows for a large proportion of identical parts even in different engine models. Modern production facilities and the latest technology guarantee a high degree of precision in individual engine parts. The scene is thus set for reliable operation when the engines go into service, and for the outstanding quality and above-average service lives of marine siesel engines from MAN. The engines are designed for optimum economy and a large operating range and precise matching of engine output to propeller design. High-speed diesel engines are used as the main engines in a wide variety of ships ranging from tugs with slow propellers to hydroplanes with hydrojets. In the rating range covered by the MAN high-speed marine diesels, the propellers used are mainly of the fixed-pitch type. This makes it necessary to match the output characteristic of the engine closely to the power consumption of the propeller under acceleration. This, in principle, varies with the 3rd power of the engine speed. In other words, if the speed of the craft is to be doubled, the drive output has to increase eight fold. The optimum adaptation of the torque and output characteristics of the MAN marine diesel engine to the propeller curve is achieved by mechanical control devices in the injection pump. These devices intervene one after the other according to the engines speed and regulate the quantity of fuel injected.

The Wastegate - for optimizing output at low speeds: One way of ensuring that the engine will achieve maximum power in the lower speed range is to use special turbochargers which offer a large quantity of combustion air even at low engine speeds. Together, with a higher quantity of fuel injected, this results in better acceleration and in a better exhaust gas quality. A bypass control (wastegate) system for the exhaust gas flow guarantees that the charge air pressure does not rise too far at higher engine speeds.
MAN Marine Diesels, Perfected Technology: MAN engines combine cultured running with superb propulsion. Their low-vibration running means that they are also extremely quiet. Both white and black smoke are cut considerably. The small space required for the engine and auxiliaries and the very favorable power-to-weight ratio mean that space on board can be used to optimum effect. The robustness of the high-speed machines, their low maintenance requirement and their high durability guarantee maximum availability. MAN marine diesel engines work reliably and economically not only at full load, but also if loads are constantly changing. And, if a high load is placed on them immediately after starting , they will deal with that too, even after being out of use for a fairly long period. If a large operating radius is required, MAN marine diesels will, thanks to their low fuel consumption, satisfy the demands placed on them.

Cooling System With Heat-exchanger Circuit: In this system the coolant circulates through the engine block, cools the exhaust pipes and the turbocharger and is recooled in the heat exchanger. Here, the heat is transferred through a copper-alloy tube bundle to seawater which is drawn in by a separate raw-water pump.
In intercooled engines, the full raw-water flow passes first through the water-to-air intercooler and then via the heat exchanger before being discharged outboard. This results in the maximum cooling of the combustion air.
In the two-stage intercooler of the 6-cylinder in-line engine the combustion air is preheated in the first stage (idling and low-load range) to prevent formation of white smoke. Under full load the changeover is then made to the second raw-water-cooled stage depending on charge air pressure.

Cooling System With Skin or Keel Cooling: This type of cooling system works using direct re-cooling of the engine coolant at the skin or in the keel of the ship

Electrical System: Bosch Sliding-gear starter motor. V-belt-driven alternator with integrated transistor regulator.

Crankcase: The crankcase and cylinder block are cast in one piece in gray cast iron. Wet replaceable cylinder liners and generous wall thickness and functional ribbing ensure stability under the most rigorous testing conditions. Rear end of crankcase sealed off by flywheel housing with SAE #1 interface (CRM series), bottom by oil pan, front end by timing gear case . All are cast in aluminum to reduce weight

Cylinder head and valve train: The cylinder heads are of a cross-flow design for each cylinder with integral swirl intake and exhaust ducts on opposite sides. They also feature shrunk-fit intake and exhaust valve inserts, pressed-in replaceable valve guides and one intake and exhaust valve per cylinder, arranged in an overhead position. Valve actuation is performed via tappets, push rods and rocker arms. The valve train is supported by a 4-bearing forged camshaft with induction-hardened cam and bearing points.

Crankshaft Group: The crankshaft is of a 7-bearing type with forged-on balance weights, induction-hardened main bearing and conrod bearing journals and additional hardening of conrod journal radii. Main and conrod bearing journals are in ready-to-install three-layer bearings. 6-cylinder engines have a torsional vibration damper mounted at the front of the engine. Connecting rods are drop-forged, strait split, and removable through the top of the cylinder. The pistons are constructed of a special aluminum alloy with ring carrier for top piston ring. The piston head is cooled by a lubricating oil jet.

Lubrication: Forced feed lubrication is handled via a gear pump for the crankshaft, conrod and camshaft bearings, valve train and , with turbo-charged engines, for exhaust gas turbocharger. The oil cooler is a combined oil filter/cooler with flat tube bundles in engine cooling system. Engine oil is cleaned in full flow by easy maintenance screw-on disposable filters with fine filter cartridges of paper.

Fuel Injection: MAN engines use Bosch fuel injectors and injection pumps. The CRM series engines have a Bosch in-line injection pump with timing device, electrical engine speed governor. Engine shut-off is achieved via separate stop lever and solenoid. Fuel filter with screw on boxes are for easy maintenance (changeover-type oil filter optional).

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Designed and developed by MGC