Marine diesel engines and their repair. Fuel system of marine diesel engine

Ship diesel engines are the source of energy that drives the ship. The rotation of the crankshaft is transmitted to the transmission, consisting of a reducer, a complex web mechanism and a propeller propeller, which gives the turn to the ship. The larger the motor ship, the more developed should be its energy system, which should ensure the safety of the vessel in navigation. If the main engine fails, a standby is activated, since stopping a huge container ship or a multi-deck dry cargo ship in the middle of the ocean in storm conditions is tantamount to its death.

First Swallow

Ship diesel engines appeared in the early twentieth century and immediately declared themselves as reliable, efficient and, most importantly, compact units. The first ship with a diesel engine was the Danish "Zeeland", launched in 1912. Two engines of 200 liters were installed on the ship. With., Each of which propelled its propeller. The appearance of a vessel with an unusual motor made a furor and was the beginning of a new era of power diesel installations.

The development of power diesel installations in the Navy began at a rapid pace after the Second World War. The prospect of further use of unpretentious propulsors was obvious, and many machine-building firms around the world engaged in their production. As is usually the case, with the development of large-scale industrial production of any product that is in high demand, competition has begun. As a result, there were unique projects, during the implementation of which, powerful, super-reliable ship engines were created.

Layout

The diesel power plant on a large ship consists of one main engine and several auxiliary ones that work on the life support of the ship. These are generators, pumps, ventilation, compressors and many other mechanisms.

On particularly large ocean liners , several main engines and a number of auxiliary ones can be installed. All motors are diesel. They are serviced by a team of mechanics, fitters and repair engineers and test engineers.

Cyclicity

Ship diesel engines are divided into four-stroke and two-stroke. The difference between the two species is significant. The four-stroke principle of operation consists in the passage of a working cycle for two revolutions of the crankshaft or four strokes of the piston. Active action occurs only during one measure, the remaining three - preparatory.

A single cycle of a two-stroke engine is performed in one revolution. The principle of compression of the combustible mixture and subsequent ignition here is different. In the cylinder there are so-called scavenging windows, by means of which a forced purging of the combustion chamber takes place and, thus, there is no need to exhaust the exhaust gases through the valves. The number of cycles is reduced exactly twice.

Additional differences

There is also a classification according to the speed of rotation. Low-turn motors - up to 150 rpm and medium-speed motors - up to 600 rpm. High-speed engines for large and very large vessels do not exist due to the specificity of their operation, high load and long-term operating time.

Marine diesel engines for small craft

Small boats, boats and river class ships are equipped, as a rule, with one motor. The power of such a diesel engine may be different, depending on the purpose for which the vessel is intended. High-speed boats have pickup engines, and for walking, sightseeing and cruise, low-speed motors are installed. Ships of the patrol coastal service usually have two sufficiently powerful diesel engines, one of which is constantly engaged, and the second is activated as needed.

Marine diesel engines for small vessels are designed for stationary installation. They are usually compact and economical, with a high service life. Outboard motors are usually gasoline, because they have the ability to quickly launch.

Diesel fuel for marine engines

For the stable operation of the power plant on the ship, it is necessary to use high-quality fuel (diesel fuel). Its suitability is determined by the following criteria:

• octane number;
• Resistance to detonation;
• Cetane number;
• Composition fractional;
• Completeness of combustion, degree of smoke, toxicity;
• Viscosity and density, as a factor of normal supply to the system;
• Properties of low-temperature, determining the functioning;
• Level of purity;
• Flash point, from the point of view of safety of application;
• Presence of sulfur compounds, metals and unsaturated hydrocarbons, as stimulants of carbon formation.

Fuel Classification:

• International - FO, HFO, MGO, MDO, IFO 380, IFO 380LS;
• Russian analogue - L-62, SMT1, CMT2, F-5, DM, IFO 380;
• Russian standard for fractions - low viscosity, medium viscosity, high viscosity, light, heavy.

The main standards adopted in Russia, regulating the quality of diesel fuel for marine engines:

• Summer "L" - used at temperatures above zero degrees Celsius;
• Winter "Z" - is used at temperatures up to minus 20 degrees;
• Arctic "A" - the temperature to minus 50 degrees Celsius.
• Low-viscosity marine fuel - produced according to TU 38.10;
• DM brand - the highest category for ship small-turn engines;
• Fuel oil fleet F-5 - produced in accordance with GOST 10-5-85; Fuel oil fleet F-30, F-180, F-380 - are manufactured according to TU 0252-003-2905.

Fuel system of marine diesel engine

Fuel supply to the power ship installation is carried out by means of the fuel system to the main and auxiliary engines. Simultaneously with the main function, the system should provide:

• Loading of fuel into tanks at the base and its storage;
• Cleaning of fuel from foreign matter and water;
• If necessary, cooling of the injectors;
• Fuel separation.

Receiving fuel from shore-based devices is carried out by means of a deck pipeline, which has choke connections on both sides. On passenger ships, fuel reception takes place in separate isolated rooms. The received fuel is stored in the tanks below deck and onboard tanks that communicate with each other. All tanks are supplied with pumps for pumping, which duplicate each other, in case of failure of one of them. Before the vessel leaves for the flight on board, the fuel is separated and purified, after which the fuel is pumped into the consumable tanks.

Marine engine brands

Energy diesel installations are produced in such quantity that it is not possible to trace their nomenclature. Famous engine manufacturers for large marine and oceanic vessels are:

• Scan Diesel (Croatia).
• Mitsubishi (Japan).
• Hyundai (South Korea).
• Lombardini Marine (Italy).
• Wartsila (Finland).

A separate category includes marine diesel engines "YaMZ", produced by the Yaroslavl Motor Plant. Diesel engines "YAMZ" for marine vessels of average displacement are the most accessible to Russian shipbuilding enterprises both at price and quality.

Repair of power ship installations

Each engine, which operates under constant load conditions, gradually develops the friction surfaces of the mechanisms. Sooner or later, there is a need for ongoing or major repairs. Shipowners try to carry out repairs on site, on their own. However, this is not always possible, because often replacement of worn parts requires special equipment, as well as qualified specialists. In this case, the engine is dismantled and sent to the manufacturer.

Repair of marine diesel engines takes several months, the ships in this case are idle. However, the shipowner may have a backup engine, which is installed instead of removed. So you can avoid forced downtime, which is very costly.

Ship giants

Among the ship engines there are record-holders. The largest marine diesel engine is the Wartsila-Sulzer-RTA96-C model. Produced in the Finnish company. The model is designed taking into account the multivariance, the line includes several types. To order a super-engine it is possible in a format of 6 or 14 cylinders. The choice is made by the customer six months before the start of work.

The cylinder diameter of this giant is 960 mm. Engine power - 109 thousand liters. from. Ocean container ship with such a motor easily develops a speed of 46 kilometers per hour.