This series of exceptionally light and compact engines, features very high reliability in every condition; furthermore, this specific project has been carried out in order to optimize durability and low fuel consumption without reducing the performance of the engine.

4 stroke marine diesel engines, fresh water cooled via heat exchanger with zinc anode protection, 4-5 cylinders in line, 16 - 20 valves driven by a twin overhead camshaft, turbocharged with intercooler, direct multiple injection with Common Rail system at 1600 Bar. Cast-iron engine block, hydraulic valve tappets, connecting rod and crankshaft steel made, water injected stainless steel exhaust elbow. Self priming sea water pump, air filter and special anti-corrosion treatment.

The Common Rail injection system makes it possible to use a high injection pressure and a fuel delivery method which are controlled by an electronic control unit through electro-injectors (rather than by injection pumps as in traditional direct injection engines). The high injection pressure is the fundamental tool for optimising torque delivery, fuel consumption and amount of exhaust smoke. The injection pressure is adjustable thanks to the constructional features of the system that is equipped with pressure pump and independent electro- injectors, all governed by a control unit. In this way, the injection pressure is independent of the engine rotation speed. The principal characteristics of the fuel delivery system are:

- high injection pressure (up to 1600 bar);

- injection pressure adjustable from 150 to 1600 bar under any operating condition of the engine;

- injection control precision both in terms of advance and duration.


Multiple Injection Common Rail

High pressure injection and electronic control of the injectors, with one additional characteristic: for every cycle of the engine, the number of injections increases, up to 5 per cycle. The quantity of diesel burnt is the same, but it is divided into more parts, resulting in a more gradual combustion and a better performance. The reduction in start-up time and amount of exhaust smoke, an amazing torque even from 1700 rpm, noise damping and emission reduction, are the advantages provided by the Common Rail JMT

The electronic control unit can manage, within the same combustion cycle, an advanced Pilot injection, a main injection consisting of a sequence of three close injections (Pre, Main, After) and a delayed Post injection, for the treatment of exhaust gases: this is made possible by varying timing depending on load output. The EDC16 control unit also enables a more precise control over the pressures and the temperatures developed inside the combustion chamber, as well as better usage of the air fed into the cylinders. In this way other objectives can be attained: control of combustion noise, lower emissions and better performance.

The electro-injectors are fitted on the cylinder head and controlled by the injection control unit. The single fuel manifold (rail) is mounted on the cylinder head suction side and allows to limit the fuel pressure oscillations caused by the pressure pump operation and the opening of the electro-injectors.

The cylinders are formed directly in the block, which is in ductile cast iron, and are available in three dimensional classes plus oversize. The cylinder head is a monoblock in aluminium and silicon alloy. There are four valves for each cylinder, two for the inlet and two for the exhaust. Parallel and vertical, they are mounted in their respective valve guides and controlled by two camshafts whose eccentric cams actuate the hydraulic valve tappets.
To ensure reliability and long-life in the demanding marine environment, and to avoid costly maintenance activities, a special fixed geometry Garrett turbine is fitted onto JMT engines, which combined with a wastegate valve for the control of the turbocharging pressure, provides excellent performance.

A heat exchanger on the diesel oil circuit enables fuel temperature fluctuations to be contained during operation of the engine, ensuring ideal safety conditions even in the presence of tanks with reduced capacity or which are partially empty.
To recharge the batteries, 105-A alternators have been installed on the LDW 194 JMT engine and 120 A alternators have been installed on the LDW 245 JMT engine, both at 14 V.
The innovative engine flywheel is the double mass type. The first mass is integral with the drive shaft, the second with the gearbox, connected by an elastic torsional damping system.