Marking of marine diesel engines. Selection of the main engine and final drive Calculation of the energy balance of the gas turbine and centrifugal compressor

Odessa 2011

1. Description of the engine design.

2. The choice of fuel and oil with an analysis of the influence of their characteristics on the operation of the engine.

3. Calculation of the engine duty cycle.

4. Calculation of the energy balance of the gas turbine and centrifugal compressor.

5. Calculation of engine dynamics.

6. Calculation of gas exchange.

7. Rules for technical operation.

8. Key question.

9. List of sources used

Applicable oils

Choice of fuel and oils

Cause

Odessa National Maritime Academy

Bibliography

Choice of the number of shaft lines and the type of propulsion

Diesel engines type VTBF

Diesels type VT2BF

Diesels of types K-EF, K-FF.

Diesels type K-GF

L-GF series diesels

Diesel engines type L-GA

Diesels type L-GB

L-GBE series diesels

L-MC/MCE series diesels

03.09.2019

Engine

Ministry of Education and Science of Ukraine

Department of SEU

course project

By discipline: "Marine internal combustion engines"

Exercise :

L50MC/MCE "MAN-B&W DIESEL A/S"

Completed:

cadet gr2152.

Grigorenko I.A.

MAIN ENGINE DESCRIPTION

Marine diesel company "MAN - Burmeister and Wine" ( MAN B&W Diesel A/S), brand L 50 MC/MCE - two-stroke single-acting, reversible, crosshead with gas turbine pressurization (with constant gas pressure p e ed turbine) with integrated thrust bearing, cylinder arrangement d ditch row, vertical.

Cylinder diameter - 500 mm; piston stroke - 1620mm; purge system - direct-flow valve.

Diesel effective power: Ne = 1214 kW

Rated speed: n n \u003d 141 min -1.

Effective specific fuel consumption in nominal mode g e = 0.170 kg/kWh.

Diesel overall dimensions:

Length (along the fundamental frame), mm 6171

Width (along the fundamental frame), mm 3770

Height, mm. 10650

Weight, t 273

The cross section of the main engine is shown in fig. 1.1. Ohla and the giving liquid - fresh water (on the closed system). Temperature pre With water at the outlet of the diesel engine in the steady state of operation 80...82 °C. Per e temperature drop at the inlet and outlet of the diesel engine - no more than 8 ... 12 ° C.

The temperature of the lubricating oil at the diesel inlet is 40...50 °C, at the diesel outlet 50...60°C.

Average pressure: Indicator - 2.032 MPa; Effective -1.9 MPa; The maximum combustion pressure is 14.2 MPa; Purge air pressure - 0.33 MPa.

The assigned resource before overhaul is at least 120,000 hours. The service life of a diesel engine is at least 25 years.

The cylinder head is made of steel. An exhaust valve is attached to the central hole with four studs.

In addition, the cover is equipped with drillings for nozzles. Other lights R leniya are intended for indicator, safety and starting cl and gentlemen.

The upper part of the cylinder liner is surrounded by a cooling jacket installed between the cylinder head and the cylinder block. Cylinder O The wedge sleeve is attached to the top of the block with a cover and is centered in the bottom hole inside the block. Density from cooling water leaks and blowing h The air supply is provided by four rubber rings embedded in the grooves of the cylinder liner. On the lower part of the cylinder liner between the cavities of the cooling water and purge air there are 8 holes R styi for fittings for supplying lubricating oil to the cylinder.

The central part of the crosshead is connected to the neck of the head heel P Nika. The cross beam has a hole for the piston rod. The head bearing is equipped with liners that are filled with babbitt.

The crosshead is equipped with drillings for supplying oil from the e telescopic tube partly for piston cooling, partly for lubrication g O catch bearing and guide shoes, as well as through the hole in the sh A tun to lubricate the crank bearing. Central hole and two chips b the sliding surfaces of the crosshead shoes are filled with babbitt.

The crankshaft is semi-compound. Oil for ram soles P nikam comes from the main lube oil pipeline. Thrust on d The bearing is used to transfer the maximum thrust of the screw through the screw shaft and intermediate shafts. The thrust bearing is installed in the feed O howling section of the fundamental frame. The lubricating oil for lubricating the thrust bearing comes from the pressure lubrication system.

The camshaft consists of several sections. Sections I are used with flanged connections.

Each engine cylinder is equipped with a separate fuel pump in s juice pressure (TNVD). The operation of the fuel pump is carried out from the cooler h washers on the camshaft. The pressure is transmitted through the pusher to the fuel pump plunger, which is connected by means of a high pressure pipe and a junction box to the injectors mounted on the central And lind cover. Fuel pumps - spool type; nozzles - with n trawl fuel supply.

Air is supplied to the engine by two turbochargers. Turbo wheel And ny TC is set in motion from the exhaust gases. A compressor wheel is installed on the same shaft as the turbine wheel, which takes air from the machine. n leg compartment and supplies air to the cooler. Installed on the cooler housing V the dehumidifier is poured. Air from the cooler enters the receiver through T covered non-return valves located inside the charge air receiver. Auxiliary blowers are installed on both ends of the receiver, which supply air past the coolers in the receiver when the non-return valves are closed. valves.

Rice. Cross section of the engine L 50MS/MCE

The engine cylinder section consists of several cylinder blocks, which are attached to the base frame and crankcase by anchor bolts. I zyami. Between themselves, the blocks are connected along vertical planes. The block contains cylinder bushings.

Piston consists of two main parts of the head and skirt. The piston head is bolted to the top ring of the piston rod. The piston skirt is attached to the head with 18 bolts.

The piston rod has a through drilling for a pipe for a cooling ma With la. The latter is attached to the top of the piston rod. Further, the oil enters through a telescopic tube to the crosshead, passes through drilling in the base of the piston rod and piston rod to the piston head. Then the oil flows through the drilling to the bearing part of the piston head to the piston rod outlet pipe and then to the drain. The rod is attached to the crosshead with four bolts through the base of the piston rod.

Used grades of fuels and oils

Applied fuels

In recent years, there has been a steady deterioration in the quality of marine heavy fuels associated with deeper oil refining and an increase in the proportion of heavy residual fractions in the fuel.

Marine ships use three main groups of fuels: low-viscosity, medium-viscosity and high-viscosity. Of the low-viscosity domestic fuels, distillate diesel fuel L has received the greatest use on ships, in which the content of mechanical impurities, water, hydrogen sulfide, water-soluble acids and alkalis is not allowed. The sulfur limit for this fuel is 0.5%. However, for diesel fuels produced from high-sulfur oil according to specifications, the sulfur content is up to 1% and higher.

Medium-viscosity fuels used in marine diesel engines include diesel fuel and marine fuel oil grade F5.

The group of high-viscosity fuels includes the following grades of fuels: DM brand motor fuel, M-0.9 marine fuel oils; M-1.5; M-2.0; E-4.0; E-5.0; F-12. Until recently, the main criterion for ordering was its viscosity, by the value of which we roughly judge other important characteristics of the fuel: density, coking capacity, etc.

The viscosity of the fuel is one of the main characteristics of heavy fuels, since the processes of fuel combustion, the reliability of operation and durability of fuel equipment, and the possibility of using fuel at low temperatures depend on it. In the process of preparing the fuel, the required viscosity is ensured by its heating, since the quality of atomization and the efficiency of its combustion in the diesel cylinder depend on this parameter. The viscosity limit of the injected fuel is governed by the engine maintenance instructions. The rate of sedimentation of mechanical impurities, as well as the ability of the fuel to exfoliate from water, largely depends on the viscosity. With an increase in the viscosity of the fuel by a factor of 2, all other conditions being equal, the time of particle settling also increases by a factor of two. The viscosity of the fuel in the settling tank is reduced by heating it. For open systems, the fuel in the tank may be heated to a temperature not less than 15°C below its flash point and not higher than 90°C. Heating above 90°C is not allowed, as in this case it is easy to reach the boiling point of water. It should be noted that the emulsion water on the value of viscosity. With an emulsion water content of 10%, the viscosity can increase by 15-20%.

Density characterizes the fractional composition, volatility of the fuel and its chemical composition. High density means a relatively higher ratio of carbon to hydrogen. Density is of greater importance when refining fuels by separation. In a centrifugal fuel separator, the heavy phase is water. To obtain a stable interface between fuel and fresh water, the density should not exceed 0.992 g/cm 3 . The higher the density of the fuel, the more difficult it becomes to control the separator. A slight change in viscosity, temperature and density of the fuel leads to the loss of fuel with water or deterioration in fuel cleaning.

Mechanical impurities in fuel are of organic and inorganic origin. Mechanical impurities of organic origin can cause the plungers and nozzle needles to hang in the guides. Getting at the moment of planting valves or nozzle needle on the saddle, carbons and carboids stick to the ground surface, which also leads to disruption of their work. In addition, carbons and carboids get into diesel cylinders, contribute to the formation of deposits on the walls of the combustion chamber, piston and in the exhaust tract. Organic impurities have little effect on the wear of fuel equipment parts.

Mechanical impurities of inorganic origin are abrasive particles by their nature and, therefore, can cause not only freezing of moving parts of precision pairs, but also abrasive destruction of rubbing surfaces, seating lapped surfaces of valves, nozzle needle and atomizer, as well as nozzle holes.

Coke residue mass fraction of carbon residue formed after combustion in a standard instrument of the tested fuel or its 10% residue. The value of the coke residue characterizes the incomplete combustion of the fuel and the formation of soot.

The presence of these two elements in the fuel is of great importance as a cause of high temperature corrosion on the hottest metal surfaces, such as exhaust valve surfaces in diesel engines and superheater tubes in boilers.

With the simultaneous content of vanadium and sodium in the fuel, sodium vanadates are formed with a melting point of approximately 625 °C. These substances cause a softening of the oxide layer that normally protects the metal surface, this causes the destruction of grain boundaries and corrosion damage to most metals. Therefore, the sodium content should be less than 1/3 of the vanadium content.

Residues from the fluid catalytic cracking process may contain highly porous aluminosilicate compounds which can cause severe abrasion damage to fuel system components as well as pistons, piston rings and cylinder liners.

Among the problems of reducing the wear of internal combustion engines, the lubrication of the cylinders of marine low-speed engines occupies a special place. In the process of fuel combustion, the temperature of the gases in the cylinder reaches 1600 ˚С and almost a third of the heat is transferred to the colder walls of the cylinder, the piston head and the cylinder cover. The downward movement of the piston leaves the lubricating film unprotected and exposed to high temperatures.

The products of oil oxidation, being in the zone of high temperatures, turns into a sticky mass covering the surfaces of pistons, piston rings and cylinder liner like a varnish film. Lacquer deposits are poor thermal conductors, so heat dissipation from a varnished piston deteriorates and the piston overheats.

cylinder oilmust meet the following requirements:

Have the ability to neutralize acids resulting from fuel combustion and protect working surfaces from corrosion;

prevent the deposition of deposits on pistons, cylinders and windows;
have a high strength of the lubricating film at high pressures and temperatures;
do not give combustion products harmful to engine parts;
have ship storage stability and insensitivity to water

Lubricating oils must meet the following requirements:

have the optimum viscosity for this type;
have good lubricity;
be stable during operation and storage;
have, if possible, a minimal tendency to soot and varnish formation;
should not have a corrosive effect on parts;
should not foam or evaporate.

To lubricate the cylinders of crosshead diesel engines, special cylinder oils for sour fuels with detergent and neutralizing additives are produced.

Due to the significant forcing of diesel engines by supercharging, the problem of increasing the engine life can be solved only by choosing the optimal lubrication system and the most effective oils and their additives.

Indicators	Standards for stamps
		Main fuel		Reserve fuel
		Fuel oil 40	RMH 55	DMA	L (summer)
Viscosity at 80˚С kinematic
Viscosity at 80˚С conditional
				absence
				absence

low-sulphurous	0.5 1			0.2 0.5
sulphurous
Flash point, ˚С
Pour point, ˚С
Coking capacity, % mass

Density at 15˚С, g/mm 3		0,991	0,890
Viscosity at 50˚С, cst
Ash content, % mass		0,20	0,01
Viscosity at 20˚С, cst				3 6
Density at 20˚С, kg/m 3


TYPE	Circulating oil	Cylinder oil
Requirement	SAE 30TBN5-10	SAE 50 TBN70-80
oil company
Elf BP Castrol Chevron Exxon Mobile Shell Texaco	Atlanta Marine D3005 Energol OE-HT30 Marine CDX30 Veritas 800 M a rine Exxmar XA Alcano 308 Melina 30/305 Doro AR30	Talusia XT70 CLO 50-M S/DZ 70 cyl.

Technical use of marine diesel engines

1. Preparation of the diesel installation for operation and diesel start-up

1.1. Preparation of a diesel plant for operation should ensure that diesel engines, service mechanisms, devices, systems and pipelines are brought into a condition that guarantees their reliable start-up and subsequent operation.

1.2. Preparation of the diesel engine for operation after disassembly or repair should be carried out under the direct supervision of the mechanic in charge of the diesel engine. In doing so, you need to make sure that:

1. the weight of the disassembled connections are assembled and securely fastened; pay special attention to locking nuts;

2. the necessary adjustment work has been carried out; special attention should be paid to the installation of zero supply of high pressure fuel pumps;

3. all standard control and measuring devices are installed in place, connected to the controlled environment andhave no damage;

4. diesel systems are filled with working media (water, oil, fuel) of the appropriate quality;

5. fuel, oil, water and air filters are clean and in good condition;

6. when pumping oil with open crankcase shields, lubricant flows to bearings and other lubrication points;

7. protective covers, shields and casings are in place and securely fastened;

8. pipelines of the fuel, oil, water and air systems, as well as the working cavities of the diesel engine, heat exchangers and auxiliary mechanisms do not have gaps in working media; special attention should be paid to the possibility of leakage of cooling water through the seals of the cylinder bushings, as well as the possibility of fuel, oil and water getting into the working cylinders or into the diesel purge (suction) receiver;

9. The diesel injectors were checked for the density and quality of the fuel spray.

After performing the checks listed above, the operations provided for preparing the diesel installation for operation after a short stop (see paragraphs 1.31.9.11) must be performed.

1.3. The preparation of a diesel installation for operation after a short stop, during which work related to disassembly was not performed, should be carried out by the mechanic on duty (of the main installation under the supervision of a senior or second mechanic) and include the operations provided for in paragraphs. 1.4.11.9.11. It is recommended to combine various preparatory operations in time.

In case of an emergency start, the preparation time can only be shortened by warming up.

1.4. Oil system preparation

1.4.1. It is necessary to check the oil level in the waste tanks or in the crankcases of the diesel engine and gearbox, in the oil collectors of turbochargers, oil servomotors, lubricators, speed controller, thrust bearing housing, in the camshaft lubrication tank. Top up with oil if necessary. Drain the sludge from the lubricators and, if possible, from the oil sump tanks. Replenish manual and wick lubricators, cap lubricators.

1.4.2. You should make sure that the devices for automatic replenishment and maintenance of the oil level in tanks, lubricators are in good condition.

1.4.3. Before cranking the diesel engine, it is necessary to supply oil to the working cylinders, cylinders of scavenging (boost) pumps and other lubricating lubrication points, as well as to all manual lubrication points.

1.4.4. Oil filters and oil coolers should be prepared for operation, valves on the pipelines should be set to the working position. Starting a diesel engine and its operation with faulty oil filters is prohibited. Remote controlled valves must be tested in operation.

1.4.5. If the oil temperature is below the recommended operating instructions, it must be heated. In the absence of special heating devices, the oil is heated by pumping it through the system during the diesel engine warm-up (see clause 1.5.4); the oil temperature during heating should not exceed 45°C.

1.4.6 It is necessary to prepare for operation and start up independent oil pumps of the diesel engine, gearbox, turbochargers or pump the diesel engine with a hand pump. Check the operation of the means of automated (remote) control of the main and standby oil pumps, bleed air from the system. Bring the pressure in the lubrication and cooling systems of the pistons to the working pressure while turning the diesel engine with a barring device. Verify that all system gauges are reading and that there is flow in the sight glasses. Pumping with oil should be carried out during the entire time of diesel preparation (with manual pumping before cranking and immediately before starting).

1.4.7. It is necessary to make sure that the emergency light signals disappear when the controlled parameters reach the operating values.

1.5. Preparing the water cooling system

1.5.1. It is necessary to prepare coolers and water heaters for operation, install valves and taps on pipelines in the working position, test the operation of remotely controlled valves.

1.5.2. The water level in the expansion tank of the fresh water circuit and in the tanks of the independent piston and nozzle cooling systems must be checked. Top up the systems with water if necessary.

1.5.3. It is necessary to prepare for operation and start up independent or standby fresh water pumps for cooling cylinders, pistons, nozzles. Check the operation of the means of automated (remote) control of the main and standby pumps. Bring the water pressure to the working level, release air from the system. The diesel should be pumped with fresh water during the entire time of diesel preparation.

1.5.4. It is necessary to warm up the fresh cooling floor with available means to a temperature of about 45°C at the inlet. The rate of heating should be as slow as possible. For low-speed diesel engines, the warm-up rate should not exceed 10°C per hour, unless otherwise indicated in the operating instructions.

1.5.5. To check the sea water system, start the main sea water pumps, check the system, including the operation of the water and oil temperature regulators. Stop the pumps and restart them immediately before starting the diesel engine. Avoid prolonged pumping of oil and water coolers with outboard water.

1.5.6. Make sure the warning lights go out when n the monitored parameters have reached their operating values.

1.6. Fuel system preparation

1.6.1. Water sludge should be drained from service fuel tanks, etc. O check the fuel level and top up the tanks if necessary.

1.6.2. The fuel filters, the viscosity regulator must be prepared for operation. O sti, heaters and coolers of fuel.

1.6.3. It is necessary to set the valves on the fuel pipeline to the working position, to test the remotely controlled valves in operation. Prep O to put into operation and start up autonomous fuel priming and cooling pumps e nozzles. After raising the pressure to the working one, make sure that there is no air at haha the system. Check the operation of the means of automated (remote) control of the main and standby pumps.

If during the parking period work was carried out related to disassembly and maintenance O rupture of the fuel system, replacement or disassembly of fuel pumps O pressure, nozzles or nozzle pipes, it is necessary to remove air from the system e we high

pressure by pumping pumps with open deaeration valves force at nok or in another way.

1.6-4. For diesel engines with hydraulic shut-off nozzles, it is necessary to check the ur O slurry vein in the tank and bring the pressure of the slurry mixture in the system to the working one, e With whether it is provided for by the design of the system.

1.6-5. If the diesel engine is structurally adapted to work at high h fuel, including starting and maneuvering, and was stopped for a long time, it is necessary to ensure gradual heating of the fuel system (tanks, pipes O wires, high pressure fuel pumps, injectors) by turning on both G roaring devices and continuous circulation of heated fuel. Before trial runs of the diesel engine, the temperature of the fuel must be O brought to a value that provides the necessary for high-quality atomization h bone (915 cSt), the fuel heating rate should not exceed 2 ° C per minute, and the circulation time I fuel in the system must be at least 1 hour, if the operating instructions A tion does not contain other instructions.

1.6.6. When starting a diesel engine on low-viscosity fuel, it is necessary to d prepare for its transfer to high-viscosity fuel by turning on the heating of service and settling tanks. Maximum fuel temperature in tanks and to be not less than 10°C below the flash point of fuel vapors in a closed ti g le.

1.6.7. When replenishing service tanks, the fuel before the separator should be well but o warm up to a temperature not exceeding 90 ° C

Fuel heating to a higher temperature is allowed only when A There is a special regulator for precise temperature maintenance.

1.7. Preparation of the start-up, purge, pressurization, exhaust system

1.7.1. It is necessary to check the air pressure in the starting cylinders, etc. O blow condensate, oil from cylinders. Prepare for work and start up the compressor, convince b in his normal work. Check the operation of automated (di With station) control of compressors. Fill up the cylinders with air up to And pressure.

1.7.2. Stop valves on the way from the cylinders to the stop valve of the diesel engine should be opened smoothly. It is necessary to purge the starting pipeline when closing s tom st o diesel valve.

1.7.3. It is necessary to drain water, oil, fuel from the purge air receiver, intake and exhaust manifolds, under-piston cavities, h stuffy cavities of air coolers of gas and air cavities of boost turbochargers.

1.7.4. All locking devices of the diesel gas outlet must be open. Make sure the diesel exhaust pipe is open.

1.8. Shafting preparation

1.8.1. Make sure there are no foreign objects on the shaft O wire, and also that the brake of the shafting is released.

1.8.2. The stern tube bearing should be prepared for operation by providing it with lubrication and cooling with oil or water. For stern tube bearings with an oil lubrication and cooling system, check the oil level in the pressure tank. h ke (if necessary, fill it up to the recommended level), as well as the lack of O oil leaks through sealing glands (cuffs).

1.8.3. It is necessary to check the oil level in the thrust and thrust bearings. And kah, check the serviceability and prepare for operation the lubricating devices according to d shipnikov. Check and prepare for operation the bearing cooling system and kov.

1.8.4. After starting the gearbox lubrication pump, check the post at oil dripping to lubrication points.

1.8.5. It is necessary to check the operation of the disengaging couplings of the shafting, for which purpose it is necessary to make several switching on and off of the couplings from the control panel. Make sure that the operation of the on and off signaling, clutch is working properly. Leave the disengaging clutches in the off position.

1.8.6. In installations with controllable pitch propellers, the propeller pitch change system must be put into operation and the checks provided for in paragraph 4.8 of Part I of the Rules must be carried out.

1.9. Cranking and trial runs

1.9.1. When preparing a diesel engine for operation after parking, it is necessary:

crank the diesel engine with a barring device by 23 turns of the shaft with indicator cocks open;

crank the diesel engine forward or reverse with compressed air;

make test runs on fuel cha forward and reverse.

When turning the diesel engine with a barring device or air, the diesel engine and the gearbox must be pumped with lubricating oil, and during test runs also with cooling water.

1.9.2. Cranking and trial runs must be carried out in installations that do not have disengaging clutches between the diesel engine and the propeller, only with the permission of the captain on duty;

in installations powered by a propeller through a disengaging clutch, with the clutch disengaged.

Cranking and trial runs of the main diesel generators are carried out with the knowledge of the senior or watch electrician or the person responsible for the operation of electrical equipment.

1.9.3. Before connecting a turning device to a diesel engine, make sure that:

1. the lever (steering wheel) of the diesel control station is in the "Stop" position;

2. the valves on the starting cylinders and the starting air piping are closed;

3. at the control posts there are signs with the inscription: “The turning device is connected”;

4. indicator cocks (decompression valves) are open.

1.9.4. When turning the diesel engine with a barring device, it is necessary to carefully listen to the diesel engine, gearbox, hydraulic couplings. Make sure there is no water, oil or fuel in the cylinders.

During cranking, follow the readings of the ammeter for the load of the electric motor of the barring device. If the limit value of the current strength is exceeded or if it fluctuates sharply, immediately stop the barring device and eliminate the malfunction of the diesel engine or shafting. It is strictly forbidden to rotate until the malfunction is eliminated.

1.9.5. Turning the diesel engine with compressed air must be done with open indicator cocks (decompression valves), drain cocks of the purge air receiver and exhaust manifold. Make sure diesel Fine picks up speed, the turbocharger rotor rotates freely and evenly, and there are no abnormal noises when listening.

1.9.6. Before trial runs of the installation, operating on controllable pitch screw (CPP), it is necessary to check the operation of the CPP control system. At the same time, you should make sure that volume, that the propeller pitch indicators at all control stations are coordinated and the blade shifting time corresponds to that specified in the factory instructions. After checking the propeller blade, set the zero pitch position.

1.9.7. Trial starts of a diesel engine on fuel must be carried out with the indicator and drain valves closed. Make sure that the start and reverse systems are working, that all cylinders are working, that there are no extraneous noises and knocks, that oil is flowing to the turbocharger bearings.

1.9.8. In installations with remote control of main diesel engines, it is necessary to carry out test runs from all control stations (from the central control room, from the bridge), to make sure that the remote control system operates correctly.

1.9.9. If, due to the conditions of the vessel’s mooring, it is impossible to make trial starts of the main diesel engine on fuel, then such diesel engine is allowed to work, but at the same time a special entry must be made in the engine log, and the captain must take all necessary precautions in case it is impossible to start or reverse the diesel engine.

1.9.10. After the preparation of the diesel engine for start-up is completed, the pressure and temperature of water, lubricating and cooling oil, and the starting air pressure in the cylinders should be maintained within the limits recommended by the operating instructions. Shut off the sea water supply to the air coolers.

1.9.11. If the prepared engine is not put into operation for a long time and must be in a state of constant readiness, it is necessary every hour, in agreement with the captain on duty, to turn the engine with a turning device with open indicator valves.

1.10. Diesel engine start

1.10.1 Diesel start-up operations must be carried out in the sequence provided for in the operating instructions. In all cases, when it is technically possible, the diesel engine must be started without load.

1.10.2. When the main diesel engines are put into operation in 5 20 min. before moving (depending on the type of installation) from the navigation bridge to the engine room, be an appropriate warning has been sent. During this time, the final operations must be performed to prepare the installation for operation: diesel engines are started, working on the propeller through uncoupling devices, the necessary switching in the systems is performed. About readiness

installations to give a move, the engineer on duty reports to the bridge in the manner accepted on board.

1.10.3 After start-up, long-term operation of the diesel engine at idle and at the lowest load should be avoided, as this leads to increased deposits of contaminants in the cylinders and flow parts of the diesel engine.

1.10.4. After starting the diesel engine, it is necessary to check the readings of all instrumentation, paying special attention to the pressure of lubricating oil, coolants, fuel and hydraulic mixture in the injector hydraulic locking system. Make sure there are no abnormal noises, knocks or vibrations. Check the operation of the cylinder lubricators.

1.10.5 If there is an automated start-up system for diesel generators, it is necessary to periodically monitor the condition of the diesel engine in the “hot standby”. In case of an unexpected automatic start of the diesel engine, it is necessary to establish the cause of the start and check the values of the controlled parameters using the available means.

1.10.6 It is necessary to ensure constant readiness for starting diesel drives of emergency units and life-saving appliances. Checking the readiness of emergency diesel generators should be carried out in accordance with paragraphs. 13.4.4 and 13.14.1 of Part V of the Rules.

Checking the operability and readiness for starting the engines of life-saving appliances, emergency fire pumps and other emergency units must be carried out by a mechanic in charge at least once a month.

Typical malfunctions and malfunctions in the operation of diesel installations. Their causes and remedies.

1. Malfunctions and malfunctions during start-up and maneuvers

1.1 When starting a diesel engine with compressed air, the crankshaft does not move or, when starting, does not make a full turn.

Cause	Measures taken
1. Shut-off valves of starting cylinders or piping are closed	Open check valves
2. Starting air pressure not enough	Refill balloons with air
3. Air (oil) is not supplied to the launch control system or its pressure is insufficient	Open valves or adjust air pressure, oil pressure
4. The crankshaft is not set to the starting position (in diesel engines with a small number of cylinders)	Set crankshaft to starting position
5. Elements of the diesel starting system are faulty (the main starting valve or the air distributor valve is stuck, the pipes from the air distributor to the starting valves are damaged, clogged, etc.)	Repair or replace system components
6. The starting system is not adjusted (the air distributor valves do not open in time, the pipes from the air distributor are incorrectly connected to the starting valves)	Adjust starting system
7. DAU system elements are faulty	Troubleshoot
8. Disturbed gas distribution (opening and closing angles of starting, intake and exhaust valves)	Adjust gas distribution
9. Barring air lock valve closed	Turn off the barring device or troubleshoot the block valve
10. Shaft line brake stuck	Release the brake
11. Propeller hits an obstruction or propeller	Release propeller
12. Freezing of water in the stern device	Warm up the stern tube

1.2 The diesel engine develops a rotation speed sufficient for starting, but when switching to fuel, flashes in the cylinders do not occur, or they occur with gaps, or the diesel engine stops.

Cause	Measures taken
1. Fuel is not supplied to the fuel pumps or is supplied, but in insufficient quantity	Open the shut-off valves on the fuel line, troubleshoot the fuel priming pump, clean the filters
2. Air got into the fuel system	Eliminate leaks in the system, bleed the system and injectors with fuel
3. A lot of water got into the fuel	Switch the fuel system to another service tank. Drain the system and bleed the nozzles.
4. Individual fuel pumps are off or defective	Turn on or replace fuel pumps.
5. Fuel enters the cylinders with a large delay	Set the required fuel advance angle
6. Fuel pumps disabled by speed limit controller	Put the regulator into operation position
7. Stuck in the regulator mechanism or shut-off mechanism	Eliminate Jam
8. Excessively high fuel viscosity	Eliminate the malfunction in the fuel heating system, switch to diesel fuel.
9. The pressure of the end of the compression and the working cylinders is not enough	Eliminate leaky valves. Check and adjust gas distribution. Check the condition of the sealing rings.
10. Diesel not warmed up enough	Warm up diesel
11. Control valves for pumping nozzles are open or leak	Close control cocks or replace nozzles
12. Closed turbocharger filters	Open filters

1.3 During start-up undermine (“shoot”) safety valves

Cause	Measures taken
1. Excessive fuel supply at start	Reduce fuel supply at start
2. The tightening of the springs of the safety valves is incorrectly adjusted	Adjust spring tension

1.4. The diesel does not stop when the control lever is moved to the "Stop" position.

Measures taken

1.Zero supply fuel pumps set incorrectly

Set control levers to

“Start” position for reverse (air braking). After stopping the diesel engine, set the lever to the “Stop” position

On a non-reversible diesel engine, close the air inlet with improvised means, or manually turn off the fuel pumps, or close the fuel supply to the pumps. After stopping the diesel engine, adjust the zero flow of the pumps

1.1 Jamming (jamming) of rails of fuel pumps

Eliminate jamming (jamming)

2. Diesel engine speed is higher or lower than normal (set)

2.1. The diesel does not develop full speed with the normal position of the fuel controls.

Cause	Measures taken
1. Increased resistance to ship movement due to fouling, headwind, shallow water, etc.	Be guided by paragraphs. 2.3.2 and 2.3.3 of Part II of the Rules
2. Fuel filter dirty	for a clean filter
3.Fuel is poorly atomized due to malfunctioning injectors, fuel pumps, or high fuel viscosity	Faulty injectors and fuel replace pumps. Raise fuel temperature
4. The fuel supplied to the diesel pumps is overheated	Reduce fuel temperature
5.Low purge air pressure	See point 8.1
6. Insufficient fuel pressure in front of diesel fuel pumps	Increase fuel pressure
7. Faulty speed controller

2.2. The engine speed drops.

Cause	Measures taken
1. Piston seizing (jamming) has begun in one of the cylinders (a knock is heard with each change in the piston stroke)	Turn off the fuel immediately and increase oil supply n and emergency cylinder, reduce the load of the diesel engine.Then stop the diesel and inspect the cylinder
2. Fuel contains water	Switch fuel system to receive from another service tank, drain water from the service tank tanks and systems
3. Plungers are jammed or suction valves are stuck in one or more fuel pumps	Eliminate jamming or replace the plunger pair, valve
4. The needle stuck on one of the nozzles (for diesel engines, Not having non-return valves on injectors and delivery valves on fuel pumps)	Replace nozzle. Delete WHO spirit from the fuel system

2.3. Diesel suddenly stops.

Cause	Measures taken
1. Water got into the fuel system	See paragraph 1.2.3
2. Faulty speed controller	Troubleshoot the regulator
3. The diesel emergency protection system has been triggered due to the control parameters going beyond the permissible limits or due to a system malfunction	Check the values of monitored parameters. Eliminate neis correctness of the system
4. The quick-closing valve on the service tank has closed	Open quick shutoff valve
5. No fuel tank	Switch to another service tank. Remove air from the system
6, Fuel line clogged	Clean the pipeline.

2.4. The rotational speed increases sharply, the diesel engine goes "peddling".

immediate action.Reduce the speed or stop the diesel engine using the control lever. If the diesel engine does not stop, close the air inlets of the diesel engine using improvised means, stop the fuel supply to the diesel engine.

Cause	Measures taken
1. Abrupt loss of load from the diesel engine (loss of a propeller, disengagement of the coupling, abrupt loss of load from the diesel generator, etc.) with a simultaneous malfunction of the regulator moat speed (all-mode and limit) or their drives	Check, repair and from regulate the regulator and the drive from it to the shut-off mechanism of the fuel pumps. Eliminate the cause of load shedding
2. Incorrectly set zero fuel supply, the presence of fuel or oil in the purge receiver, a large drift of oil from the crankcase into the combustion chamber of a trunk diesel engine (the diesel engine accelerates after starting at idle or removing the load)	Load diesel immediately orstop air from entering the air intakes. After stopping, adjust the zero flow, inspect the diesel

Vanscheidt V.A., Design and strength calculations of marine diesel engines, L. "Shipbuilding" 1966

Samsonov V.I., Marine internal combustion engines, M "Transport" 1981

Handbook of ship mechanic. Volume 2. Under the general editorship of Gritsai L.L.

4. Fomin Yu.Ya., Marine internal combustion engines, L .: Shipbuilding, 1989

MAN and Burmeister and Wein-ME electronically controlled engines (2) >

The first electronically controlled motor by MAN was created on the basis of the MC model in 2003. In this engine, the company abandoned the camshaft with its drive and introduced electronic control: the fuel supply process, speed control, replacing the mechanical regulator with an electronic one, engine starting and reversing processes, exhaust valve and cylinder lubrication.

increase

Fuel injection and exhaust valves are controlled by hydraulic actuators. The oil used in the hydraulic system is taken from the circulating lubrication system, passed through a fine filter and compressed by engine-driven or electric pumps (at start-up) to a pressure of 200 bar. Next, the compressed oil flows to the diaphragm accumulators and from them to the fuel injection pressure boosters and exhaust valve hydraulic drive pumps. From the diaphragm accumulators, the oil enters the electronically controlled proportional valves ELFI and ELVA, which open under the influence of a signal from the electronic modules (CCU) installed for reliability on each cylinder.

increase

Injection pressure boosters are piston servomotors in which a large-diameter piston is exposed to oil at a pressure of 200 bar, and a small-diameter piston (plunger), which is an extension of the large-diameter piston, when it moves up, compresses the fuel to pressures of 1000 bar (ratio the area of the servo piston and plunger is 5). The moment when oil enters under the servomotor piston and the beginning of fuel compression is determined by the receipt of a control pulse from the CCU electronic module. When the fuel pressure reaches the opening pressure of the nozzle needle and injection stops when the fuel pressure drops, the latter is determined by the moment the control valve closes and the oil pressure in the servomotor is released.

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The choice of the type of main gear and the main engine will be made in the complex. The selection of options for the main engine will be made on the basis of the calculated effective power. Consider 3 diesels:

Characteristics of the received internal combustion engines.

Required power of one main engine = kW

The table shows that the MAN-Burmeister and Vine S60MC has the lowest specific fuel consumption, it is low-speed, which allows it to work on a propeller without using a reduction gear. These indicators increase the efficiency of the engine and simplify the operation process.

Summing up, we accept as a variant of the SPP installed on the designed vessel, SDU. As the main engine and transmission type, we accept the MAN-Burmeister and Vine MOD S60MC with direct transmission and VFS. To provide the required power, it is necessary to install two such engines.

Main characteristics of the MAN-Burmeister and Vine S60MC engine

The number of shaft lines is selected from the task for the course project in accordance with the number of propellers. The designed vessel should have two propellers. MODs with direct transmission are used as the main ones, so I decide to install two single-shaft SDUs. This scheme provides high survivability and maneuverability. When choosing the type of propulsion, the advantages and disadvantages of each type, the feasibility of its use on a given vessel, the initial cost of the vessel and operating costs are considered. Installation with VFSh is simpler and cheaper, more convenient to maintain, the most maintainable, in comparison with VFSh. Also, the CPP has a slightly lower efficiency (by 1-3%) than that of the VFS. due to the large diameter of the hub, which houses the turning mechanism. This determined the wide distribution of installations with VFS on ships of the transport marine fleet with established navigation regimes: oil tankers, dry cargo ships, timber carriers, coal carriers, transport refrigerators, and fishing fleet vessels.

The use of an adjustable pitch propeller makes it possible to quickly switch from forward to reverse and improves the maneuverability of the vessel.

From the above it follows that for this vessel it would be appropriate to use the VFS.

Since 1939, the Danish company Burmeister and Vine, together with licensees, has been producing low-speed marine engines with a direct-flow valve scavenging system, and since 1952 - with gas turbine supercharging.

The domestic fleet currently operates engines of the VTBF, VT2BF, K-EF, K-FF, K-GF, L-GF, L-GFCA series.

The general layout of the VTBF engines is shown in fig. 23 cross section of the 74VTBF-160 engine. (DKRN74/160), This is a two-stroke, crosshead, reversible engine with direct-flow valve scavenging and pulsed gas turbine supercharging.

The engine is supercharged by Burmeister and Wein gas turbochargers of the TL680 type, which are installed on every two to three or four cylinders, depending on the engine row.
Exhaust gases enter the turbine at a variable pressure with a temperature of about 450 ° C through individual pipes from each cylinder, which have protective grilles, which, in the event of a breakage of the piston rings, should protect the flow path of the gas turbine from debris.

The engine is provided with air in all modes from full speed to starts and maneuvers only by a gas turbocharger due to the early opening of the exhaust valve. The valve opens at 87° -p. q.v. to BDC, and closes at 54 ° p. to. after NMT.
Purge windows open and close at 38° sc. before and after BMT, respectively. The early opening of the valve makes it possible to obtain a powerful pressure impulse, which ensures the balance of power between the turbine and the compressor in all operating modes, however, the company additionally installed an emergency blower 9.

Direct-flow valve purge in Burmeister and Wein engines is traditionally carried out using a single large-diameter valve 1 located in the center of the cylinder cover 2.
For this reason, in order to evenly distribute the sprayed fuel throughout the volume of the combustion chamber, two or three nozzles with one-sided arrangement of nozzle holes are installed along the periphery of the cover 2, which previously had a conical shape, which made it possible to move the poorly cooled area of the junction of the cover with the cylinder sleeve 3 from the zone of the combustion chamber up .

The use of such a purge scheme made it possible to use a simple symmetrical design of a cylinder bushing, in the lower part of which purge windows 6 are located, evenly distributed around the entire circumference of the bushing. The axes of the channels forming the purge windows are directed tangentially to the circumference of the cylinder, which creates a swirling of the air flow when it enters the cylinder.
This ensures that the cylinder is cleaned of combustion products with minimal mixing of purge air and residual gases, and also improves mixture formation in the combustion chamber, since the rotation of the air charge is maintained at the time of fuel injection.
A simple configuration and the ability to ensure uniform temperature deformation of the sleeve along the length provide favorable operating conditions for the parts of the cylinder-piston group.

The piston 4 of the engine has a steel head made of molybdenum heat-resistant steel and a very short cast-iron trunk. Due to the peripheral arrangement of the nozzles, the piston crown has a hemispherical shape.
The uniform blowing of the piston crown with cold air during blowing allowed the company to maintain oil cooling of the piston in all models of its engines. The use of an oil cooling system greatly simplifies both the design and operation of the engine.
To improve the maintainability of the pistons, anti-wear cast iron rings are installed in the grooves of the piston rings of the VTBF engines and the two subsequent modifications. When worn or broken, they are replaced. This restores the original height of the groove.

Having carried out the welded construction of the foundation frame and crankcase struts, the company tried to use shortened anchor ties in these engines, passing from the upper plane of the cylinder block to the upper edge of the crankcase struts, instead of traditional long anchor ties.
However, operating experience has shown that with short anchor ties, the necessary rigidity of the skeleton is not provided, therefore, in subsequent models, they returned to long anchor ties.

VTBF engines have two camshafts. Their drive from the crankshaft 8 is carried out by a valuable transmission traditional for the MOD of the Burmeister and Wein company. The upper camshaft drives 5 exhaust valves and the lower camshaft drives 6 high pressure fuel pumps.

The reverse of the exhaust camshafts and fuel pumps is carried out using rocker servomotors with planetary gears mounted inside the drive sprockets. When reversing, each camshaft is locked by a brake valve and remains stationary for a predetermined angle as the crankshaft is rotated in the new direction.
In this case, the camshaft of the fuel pumps turns out to be deployed relative to the crankshaft by 130 ° c.c. In order to reduce the reverse angle, the camshafts are turned in different directions.

The crankshaft of the engines of this series is composite, i.e., both the crank and the frame journals are pressed into the cheeks. Crank bearings are lubricated through channels in the necks and cheeks.

From the crank bearing, oil flows through the holes in the connecting rod to the crosshead, then to the lubrication of the head bearings.

The supply of cooling oil to the piston is carried out through telescopic pipes through the crosshead, then the oil rises to the piston along the annular gap between the piston rod and the outlet pipe.
The used oil from the piston is drained through a pipe located inside the piston rod, then from the crosshead along a jib, the free end of which goes into the slots of the non-moving outlet pipe, and then the oil enters the waste tank through the pipe system.

On Burmeister and Wein engines, traditionally used high pressure fuel pump 7 spool type with regulation at the end of the feed. On VTBF engines, the lines to both injectors are connected directly to the fuel pump head.
The pump does not have delivery valves, and the fuel supply advance angle is controlled by turning the cam relative to the camshaft. The nozzles of these engines are of a closed type, cooled by diesel fuel, the injection start pressure is 30 MPa. A characteristic feature of the nozzles is the mechanical seal of the needle.

The experience of operating VTBF type diesel engines on ships of the domestic fleet has shown that they are characterized by the following defects and malfunctions: intensive wear of cylinder bushings, loosening of the pins for fastening the head and piston trunk, frequent breakdowns and intensive wear of piston rings, formation of cracks under the support collar of the cylinder bushing, failure of anti-wear rings, cracking and peeling of the babbitt of the head and crank bearings, burning of the exhaust valves, cracking of parts and freezing of the injection pump plungers, frequent nozzle failures due to hanging needles, cracking of sprayers, etc. However, in general, the engines showed sufficient reliability at a coefficient power use 0.8-0.9.

The next engine model, produced by the company since 1960, VT2BF, retained the main features of the previous model: pulse gas turbine pump 2, direct-flow valve purge, oil cooling of the piston, composite crankshaft 1, camshaft drive 4, etc. However, in new series, the average effective pressure increased from 0.7 to 0.85 MPa, by about 20%.
To increase the power of the turbine, the opening phase of the exhaust valve 3 was increased from 140 to 148 ° c.c. The exhaust valve now opened beyond 92° c.c. to BDC and closed at 56 ° p. to. after her.

In order to simplify the design and reduce the weight of the engine, the company abandoned the use of two camshafts. Starting with this model, a single camshaft is used to drive the injection pump and exhaust valves. To increase the rigidity of the engine frame, the company returned to long anchor ties 7 extending from the upper plane of the cylinder block 5 to the lower plane of the foundation frame 6.

The reverse of the camshaft is carried out by its turn by 130 ° c.c. towards the reverse of the exhaust valve cams, so the company was forced to use a cam with a negative profile to drive the injection pump.
In connection with a sharp reduction in the filling time of the pump, the company installed a suction valve in the injection pump head. In addition, the engines of this series use an eccentric mechanism for changing the fuel supply advance angle (Fig. 26), which regulates the maximum combustion pressure without stopping the engine, which is an undoubted advantage of this design.

From the injection pump, fuel is supplied through the discharge pipeline to the junction box, from which the pipelines go to the injectors. Having retained the mechanical seal of the needle with the sprayer, the company lowered the nozzle spring down, thereby reducing the mass of moving parts. The absence of a pressure valve in the injection system with a powerful cut-off of fuel at the end of the supply often led to the formation of vacuum cavities in the high-pressure fuel lines, causing uneven cycle feeds through the cylinders.

Diesels types K-EF, K-FF

The engines retain pulse gas turbine supercharging, direct-flow valve gas exchange, oil cooling of the piston and other characteristic features of the engines of the previous VT2BF model. The general layout of the engines of this series is shown in the cross section of the K84EF engine in fig. 27.
Some changes have been made to the engine design. First of all, this concerns the details of the combustion chamber. As can be seen from fig. 28, the combustion chamber of K98FF engines is placed in a cap-type cover.
This reduced the temperature of the cylinder mirror in the upper part of the bushing, which was facilitated by the cooling of the upper belt of the bushing with water supplied through drilled tangential channels in the support shoulder 4. The cap design provided sufficient rigidity and strength of the cover without increasing the thickness of the walls of the combustion chamber, despite the fact that the diameter of the cylinder and pressure Pz became more.
The thickness of the upper part of the sleeve was left unchanged due to its downward displacement to the region of lower gas pressures. With this arrangement of parts of the combustion chamber, the upper part of the piston protrudes from the cylinder liner when it is in the TDC position.
Therefore, it became possible to abandon the threaded holes for the frames in the piston bottom, which are stress concentrators, and to use a device for dismantling the piston, traditionally used in MAN engines, in the form of a clamp, the shoulder of which enters the annular recess in the upper part of the piston 5.

To ensure sufficient heat removal from the piston bottom and its mechanical strength, the company retained the previous thickness of the bottom, and to reduce deformations arising from gas pressure, used a support cup 3; whose diameter is 0.7 of the cylinder diameter.
This achieves a balance of gas pressure forces on the central and peripheral surfaces of the piston bottom, which makes it possible to reduce bending stresses at the transition point of the bottom to the side walls. Belleville spring ring 1 is used to fasten the piston to the rod.
Due to the elasticity of this ring, automatic wear compensation is provided for the bearing surfaces of the support cup, piston crown and rod. Thanks to these measures, it was possible to maintain an acceptable temperature level in the details of the cylinder-piston group, despite the increase in the average effective pressure due to supercharging by 10% compared to VT2BP diesels.

Significant changes have been made to the high-pressure fuel pump of engines of this series. The company abandoned the use of an eccentric mechanism with fuel advance angle adjustment and used a movable plunger sleeve, the position of which can be adjusted when the pump is turned off using a small gear drive. When the drive gear rotates, an intermediate sleeve is screwed onto the cover, which serves as a stop for the plunger sleeve.
The plunger sleeve itself is pressed against the intermediate one with the help of four pins. When adjusting the fuel injection advance angle while the engine is running, the fuel supply is turned off, the plunger sleeve fastening studs are loosened, and then, by rotating the toothed gear, the adjusting sleeve is screwed on or unscrewed onto the pump head, moving it to the desired height. In addition, the company used a plate suction valve located directly in the injection pump.

Fuel is supplied to the discharge cavity through the annular gap between the housing and the plunger bushing from the bottom up, which allows the pump to be heated evenly when operating on heavy fuel. A spring damper is used to dampen the pressure waves generated during cut-off.

The company implemented the improvement of the design of its engines in the process of fine-tuning the base engine K90GF, and then all other engines of this series. Due to supercharging, the engine power was increased by almost 30% compared to the K-EF models, the average effective pressure was 1.17-1.18 MPa with a maximum combustion pressure of 8.3 MPa. This led to a significant increase in loads on all parts of the engine frame.
Therefore, the company completely abandoned its previous design, formed by separate A-shaped racks, and switched to a more rational rigid welded box-shaped structure, in which the lower block 8, together with the foundation frame 9, forms the space of the connecting rod mechanism, and the upper block 7 forms the crosshead cavity along with parallels.

This option reduces the number of bolted connections, simplifies the processing of individual sections and facilitates the sealing of the seals. To improve the working conditions of the crosshead 6, the diameter of the necks of its cross member was significantly increased, which became approximately equal to the diameter of the cylinder, and their length was shortened (up to 0.3 of the neck diameter).
As a result, the deformation of the crosshead decreased, the pressure on the bearings decreased (up to 10 MPa), the circumferential speeds in the crosshead bearing increased somewhat, which contributes to the formation of an oil wedge. The symmetry of the crosshead assembly allows, in case of damage to the neck, to turn the cross member by 180 °.

Due to the high level of thermal and mechanical stresses in operation, failures of the combustion chamber parts were observed: covers, bushings and pistons. To eliminate these shortcomings and in connection with the need for further forcing the engine by supercharging, Burmeister and Wein decided to redesign the design of these parts.

The cast caps have been replaced by forged steel ones, they are of semi-cap type and have a reduced height. To intensify cooling, about 50 radial channels were drilled near the surface of the firing bottom, through which cooling water circulates.
A number of tangential holes are also made in the thickenings of the flange belts of the cover 2 and the bushing 5, forming circular channels for the passage of cooling water. Due to the intensive cooling of the upper belt of the sleeve, the temperature of the cylinder mirror at the level of the upper ring at the piston position at TDC does not exceed 160-180°C, which ensures reliable operation and increases the service life of the piston rings, as well as reduces wear of the sleeve.
At the same time, the company managed to keep the oil cooling of piston 3, the head of which remained approximately the same as in the previous series of K-EF engines, but without wear rings.

To increase the reliability of the exhaust valve (1), the mechanical drive of this valve was replaced with a hydraulic drive, and the large diameter concentric springs were replaced with a set of 8 springs.
The hydraulic drive transmits the forces of the piston pusher 6, driven from the camshaft cam, through the hydraulic system to the servomotor piston acting on the exhaust valve spindle. The oil pressure when the valve is opened is about 20 MPa.
The operation has shown that the hydraulic drive is more reliable in operation, makes less noise, provides less wear on the valve stem due to the absence of lateral forces, which increased the valve service life to 25-30 thousand hours.

Due to the fact that two to three injectors were installed on each cylinder of Burmeister and Wein engines with a direct-flow valve scavenging, their insufficient reliability seriously reduced the failure-free operation of the engines.
For this reason, the design of the nozzles has been completely redesigned (Fig. 33). In the new nozzle, fuel is supplied through a central channel formed by drillings in the nozzle head, in the rod, in the stop and in the non-return pressure valve. The discharge valve itself is located in the body of the nozzle needle. The sealing of all joints between the parts that form the central channel for supplying fuel is carried out only due to their mutual grinding and the force created as a result of interference during assembly of the nozzle. The removable nozzle is made of high quality steel.
This allows you to increase not only the reliability of the sprayers themselves, but also their maintainability. The nozzle does not have a device for regulating the opening pressure of the needle. Experimental testing of such injectors on engines showed their high reliability.

The intensification of cooling of the cylinder cover in the area of the nozzle hole made it possible to dispense with the cooling of the atomizer. The placement of the discharge valve in the needle in the immediate vicinity of the nozzle, on the one hand, completely eliminates the possibility of fuel injection, and on the other hand, guarantees the fuel system from gas breakthrough from the cylinder when the nozzle needle hangs. short and fit them into the holes drilled directly in the steel body of the cover.

On fig. 34 shows the top marvelous pump engine of this type. Its design preserves the supply of fuel to the pump along the annular gap between the plunger bushing and the body from the bottom up for uniform heating of the plunger pair when switching to heavy fuel, the same principle of regulating the start of supply by axial movement of the plunger bushing is used, the suction valve is located on the side of the discharge cavity, etc. d.
However, taking into account operating experience, a special seal has been introduced to reduce fuel leakage through the gap in the plunger pair. The cyclic feed control rail has been moved to the lower part of the pump housing.

Launched on the market in 1973, the K-GF engines were designed to meet the requirements of the shipbuilding industry, which was based on low fuel prices and high freight rates. Tendencies to increase aggregate capacities prevailed, which made it possible to reduce production costs per unit of power of produced diesel engines.

The energy crisis forced Burmeister & Wein, as well as other firms, to move to the creation of engines with a large ratio of S to D. The engines of this series were labeled L-GF. An increase in piston stroke compensated for a 20% reduction in rotational speed and allowed the cylinder power to be maintained at the same level.

Many components of the L-GF engines are completely identical to those of the K-GF engine (fig. 35): forged steel cover 2 with drillings for cooling water supply, hydraulic actuator of the exhaust valve 1, oil-cooled piston design 3, crosshead 5, engine frame etc. The upper part of the sleeve 4 was taken out of the cylinder block and made in the form of a thick support shoulder of considerable height, in which tangential channels were drilled for supplying cooling water.

Reducing the speed of long-stroke engines made it possible to increase the diameter of the propeller and, as a result, increase propulsion efficiency by approximately 5%. Tests of the built diesel engines showed that with a long-stroke design, the indicator efficiency of the diesel engine also increases by 2-3%, since the work of gas expansion is more fully used.
The advantages of a direct-flow-valve gas exchange scheme were confirmed, due to which an increase in the height of the cylinder did not lead to an increase in the mixing zone of air with residual gases, as happened in engines with scavenging circuits.

Diesels of the L-GFCA series. The preservation of pulsed gas turbine supercharging in L-GF engines did not allow obtaining the required level of efficiency in the conditions of the energy crisis. In this regard, at the end of 1978, Burmeister & Wein tested the first isobaric supercharged engine at the factory bench, in which a specific fuel consumption of about 190 g / (kWh) was achieved. The new series of engines received the designation L-GFCA.

The exhaust pipes of the cylinders are connected to the common exhaust manifold 3 of a large volume, therefore, almost constant gas parameters are set in front of the turbine 2. The transition to supercharging at a constant gas pressure in front of the turbine made it possible to increase the efficiency of the turbocharger by 8% and thereby improve the air supply to the engine in the main operating modes.
At the same time, at low loads and when starting the engine, the available gas energy in front of the turbine is not enough, so in these modes it was necessary to use two blowers with a capacity of 0.5% of the total diesel power.

In connection with the transition to constant boost, there was no need to open the exhaust valve 4 early, which ensured a powerful impulse of gases with a pulse boost system.
Instead of opening beyond 90 ° c. to BDC, the valve began to open at 17-20 ° c.c. later. The unchanged cam profile made it possible for the valve to close as much later, and its entire time-section diagram became more symmetrical with respect to BDC.
Apparently, the company went to increase the loss of charge during gas exchange, primarily to reduce the temperature of the piston and especially the exhaust valve, the temperature of which exceeded 500°C.
A slight decrease in pressure at the beginning of compression makes it possible to obtain an additional gain in power (zone //). Due to this, as well as due to an increase in the maximum combustion pressure from 8.55 to 9.02 MPa (zone ///) and an increase in the duration of the gas expansion process as a result of a later opening of the valve (zone /), the average indicator pressure in the engine L- GFCA increased compared to the L-GF engine from 1.26 to 1.40 MPa.

The increase in engine efficiency was achieved by reducing the specific fuel consumption by 7.5%, which was also facilitated by deep cooling of the purge air.
According to the company, every 10°C reduction in the scavenge air temperature allowed for a 0.8% reduction in fuel consumption. Deep air cooling is associated with the loss of water vapor condensate from it, which can cause wear of CPG parts. This difficulty was eliminated by installing moisture separators in air coolers 1 (see Fig. 36), consisting of a set of profiled plates. Condensate drops contained in the air stream are discharged from the plates into the drainage system.

The company has been researching the possibility of choosing between full use of built-in engine power and reducing the speed of the vessel for maximum fuel economy.

They showed that L-GFCA engines can operate at a constant value of maximum combustion pressure in the power variation range from 100 to 85% Nenom. (when the engine is running on the propeller).
The results of these studies are presented by the calculation diagram, a. The zone of modes, in which it is allowed to maintain the nominal values of Pz, is limited by the figure 1-2-3-4-5. Work in zone 1-6-2 is associated with the excess of the nominal values of the specific pressures on the bearings.

If it is necessary to fully use the building power (i.e., maintain maximum speed), the engine operating modes should be located near the 5-1-2-3 border.
The specific position of the regime point will depend on the location of the real helical characteristic. If it is necessary to move in an economical way, the regime point should be located closer to the border 3-4-5. Rice. 38.6 shows that. in this case, the hourly fuel consumption will decrease due to a decrease in both power and specific effective fuel consumption (points A to B).

The first model of the L-GA engine developed by the joint company MAN - "B and C" differed from the previous modification L-GFCA only in the use of the NA-70 turbocharger developed by MAN.
Increasing the efficiency of the turbocharger from 61 to 66% reduced the effective specific fuel consumption by 2 g/(kWh) at rated power and by 2.7 g/(kWh) at 76% Nenom. Since when equipping a diesel engine with a more efficient turbocharger, the task of increasing the average effective pressure was not set, an increase in its efficiency was used to reduce the available gas energy in front of the turbine due to the later opening of the exhaust valves. This made it possible to make fuller use of the expansion of gases in the diesel cylinders, which increased its efficiency. All other parameters of the L-GA engine remained the same as those of the L-GFCA.

The high efficiency of the new turbochargers and the later opening of the exhaust valves have reduced the temperature of the exhaust gases behind the turbine by 20-25°C. As a result, the steam output of the utilization boiler also decreased. In order to partially compensate for the decrease in gas temperature, it was decided to use turbochargers with uncooled housings of the NA-70 type from MAN.

The L-GA modification served as an intermediate model in the transition to diesel engines with increased boost and better efficiency of the L-GB series. In these engines, pe was increased to 1.5 MPa and the cylinder power of diesel engines was increased by 13% (compared to L-GFCA diesel engines). The specific fuel consumption was reduced by 4 g/(kWh) due to the use of more efficient turbochargers and an increase in Pz to 10.5 MPa. Due to the increase in the level of thermal and mechanical loads, all details of the movement and the CPG, as well as the skeleton, have been strengthened, although the overall layout has remained unchanged in relation to the L-GFCA engines.

To improve the reliability of the exhaust valve, its design has been redesigned: the springs have been replaced by a pneumatic piston operating at an air pressure of 0.5 MPa, a impeller is used to rotate the valve, and the valve seat is cooled through drilled channels.

New oil-cooled piston design.

To automatically maintain a constant pressure in the load range from 78 to 110%, a mixed-regulation spool pump was used. The special configuration of the cut-off edges 1 of the plunger provides an increase in injection advance with a decrease in engine load, maintaining the maximum combustion pressure at the nominal level.

When the load decreases below 75%, the moment of the beginning of the flow through the pump gradually begins to decrease, and at about 50% of the load, the pressure Pz becomes the same as with the pump of the previous design.

Simultaneously with the L-GB series, MAN B&V developed its improved L-GBE modification in terms of efficiency. The engines of this modification have the same speed dimensions as the L-GB engines, but the nominal mean effective pressure is reduced to the level of L-GFCA diesels while maintaining the maximum combustion pressure at a high level and a higher compression ratio.

To reduce the volume of the compression chamber, special gaskets are installed under the heel of the piston rod. Turbochargers of L-GBE diesel engines have different sizes of flow parts, respectively, the dimensions of the purge windows and the phase of the exhaust valve have been changed.
There are also differences in the design of nozzle sprayers and injection pump plungers. Due to the automatic increase in the advance angle of the fuel supply when the plunger turns with a decrease in power, the Load diagram at pz=const changes slightly: the line of the helical characteristic becomes the boundary of low speeds, i.e., the left generatrix of the zone of constant pz values. As a result, this zone expands significantly.

Small size model L35GB/GBE (see table 8). redesigned. In connection with the increase in combustion pressure to 12 MPa, the cast-iron cylinder block is made cast, the crankshaft is solid forged, the design of the reverse mechanism has been changed.

cylinder
power, kWt

The number of qi-

Effective
power, kWt

Specific
fuel consumption
VA, g/kWh

revolutions,

"MAN-Burmeister
and Vine S50MC-C"

"MAN-Burmeister

"MAN-Burmeister

The next model of the company MAN-"B and V" was an extra-long-stroke model with a ratio of S / D = 3.0 - 3.25, which received the L-MC / MCE marking. Due to a further increase in the piston stroke and a simultaneous increase in Pz, the specific effective fuel consumption in the L90MC/MCE engine was 163–171 g (kWh). In an effort to satisfy the needs of shipbuilding as fully as possible, the company MAN-"B and V" in 1985 announced the preparation for the production of two modifications of the MOD S-MC / MCE K-MS / MCE (Table 9). Models S-MC and S- MCE have an S/D=3.82 ratio and provide record low fuel consumption up to 156 g/(kWh),

The K-MS and K-MCE models with S/D=3 have a 10% higher rotational speed compared to similar engines of the L-MC/MCE models, as it is designed for container ships and other high-speed vessels with limited aft clearance space not, allows the use of low-speed propellers of large diameter.

In the 12K90MS engine, a rated power of 54 thousand kW can be provided.

The main design solutions used by the company in diesel engines of the latest modifications remained unchanged in relation to diesel engines of L-MC / MCE models. foundation frame 7 is welded, box-shaped with solid transverse beams, its height provides greater rigidity. A solid cast iron purge air receiver 1 is integrated with the cooling jackets of the cylinder blocks.

In cylinder bushings 6, the temperature is distributed evenly, wear at low consumption of cylinder lubrication is small. Cylinder cover 4-steel forged, has a system of drilled channels for cooling.

Spool-type fuel pumps with mixed flow control provide low fuel consumption. Exhaust valves 2 in the cylinder covers are hydraulically driven and have a turning device, which increases the reliability of their mating with cooled seats. Pistons 5 are oil cooled.

The efficiency of the engines has been improved by utilizing exhaust gas heat in a standardized turbocompound system 3, which is available in two versions: a turbocharger with an electric generator built into the air filter muffler, or a waste turbogenerator. In this case, additional energy can be given to the propeller or to the ship's electrical network.

Marine diesel of the company "MAN - Burmeister and Wein" (MAN B&W Diesel A / S), brand L50MC / MCE - two-stroke single-acting, reversible, crosshead with gas turbine pressurization (with constant gas pressure in front of the turbine) with built-in thrust bearing, cylinder arrangement in-line , vertical.

Cylinder diameter - 500 mm; piston stroke - 1620mm; purge system - direct-flow valve.

Diesel effective power: Ne = 1214 kW

Rated speed: n n \u003d 141 min -1.

Effective specific fuel consumption in nominal mode g e = 0.170 kg/kWh.

Diesel overall dimensions:

Length (along the fundamental frame), mm 6171

Width (along the fundamental frame), mm 3770

Height, mm. 10650

Weight, t 273

The cross section of the main engine is shown in fig. 1.1. Coolant - fresh water (in a closed system). The temperature of fresh water at the outlet of the diesel engine in the steady state of operation is 80...82 °C. The temperature difference at the inlet and outlet of the diesel engine is no more than 8...12°C.

The temperature of the lubricating oil at the diesel inlet is 40...50 °C, at the diesel outlet 50...60°C.

Average pressure: Indicator - 2.032 MPa; Effective -1.9 MPa; The maximum combustion pressure is 14.2 MPa; Purge air pressure - 0.33 MPa.

The assigned resource before overhaul is at least 120,000 hours. The service life of a diesel engine is at least 25 years.

The cylinder head is made of steel. An exhaust valve is attached to the central hole with four studs.

In addition, the cover is equipped with drillings for nozzles. Other drillings are for indicating, safety and starting valves.

The upper part of the cylinder liner is surrounded by a cooling jacket installed between the cylinder head and the cylinder block. The cylinder bushing is attached to the top of the block with a cover and centered in the bottom hole inside the block. The tightness against leakage of cooling water and scavenging air is ensured by four rubber rings embedded in the grooves of the cylinder liner. On the lower part of the cylinder liner between the cavities of the cooling water and scavenging air, there are 8 holes for fittings for supplying lubricating oil to the cylinder.

The central part of the crosshead is connected to the head bearing journal. The cross beam has a hole for the piston rod. The head bearing is equipped with liners that are filled with babbitt.

The crosshead is equipped with drillings for supplying oil supplied through a telescopic tube partly to cool the piston, partly to lubricate the head bearing and guide shoes, and also through the hole in the connecting rod to lubricate the crank bearing. The central hole and the two sliding surfaces of the crosshead shoes are filled with babbitt.

The crankshaft is semi-compound. The oil for the frame bearings comes from the main lube oil line. The thrust bearing is used to transfer the maximum thrust of the screw through the screw shaft and intermediate shafts. The thrust bearing is installed in the aft section of the fundamental frame. The lubricating oil for lubricating the thrust bearing comes from the pressure lubrication system.

The camshaft consists of several sections. Sections are connected by means of flange connections.

Each engine cylinder is equipped with a separate high pressure fuel pump (TNVD). The operation of the fuel pump is carried out from the cam washer on the camshaft. The pressure is transmitted through the pusher to the fuel pump plunger, which is connected to the injectors mounted on the cylinder head by means of a high pressure pipe and a junction box. Fuel pumps - spool type; nozzles - with a central supply of fuel.

Air is supplied to the engine by two turbochargers. The TC turbine wheel is driven by the exhaust gases. A compressor wheel is mounted on the same shaft as the turbine wheel, which takes air from the engine room and supplies air to the cooler. A moisture separator is installed on the cooler body. From the cooler, air enters the air receiver through open non-return valves located inside the charge air receiver. Auxiliary blowers are installed on both ends of the receiver, which supply air past the coolers in the receiver with non-return valves closed.

Rice.

The engine cylinder section consists of several cylinder blocks that are anchored to the base frame and crankcase. Between themselves, the blocks are connected along vertical planes. The block contains cylinder bushings.

The piston consists of two main parts, the head and the skirt. The piston head is bolted to the top ring of the piston rod. The piston skirt is attached to the head with 18 bolts.

The piston rod is drilled through for the cooling oil pipe. The latter is attached to the top of the piston rod. Further, the oil enters through a telescopic tube to the crosshead, passes through drilling in the base of the piston rod and piston rod to the piston head. Then the oil flows through the drilling to the bearing part of the piston head to the piston rod outlet pipe and then to the drain. The rod is attached to the crosshead with four bolts through the base of the piston rod.

Used grades of fuels and oils