What is the purpose of safety air in main engine?

This is done as a precautionary measure to prevent damage to the engine while starting, if there were an oil or water leakage. Interlocks are the blocking devices which ensure that the engine is started or reversed only when some conditions are fulfilled or satisfied.

What is the function of air starting system?

An air-start system is a power source used to provide the initial rotation to start large diesel and gas turbine engines.

What is NCR in marine engine?

NCR Normal Continous Revolution. Both Of Them Discribes Capacity/rating Of Main Engine Of Ships.

What is starting control pressure?

When the engine is required to start, a low pressure air signal is sent to the air start control valve (which can also be hand operated in an emergency). The air pushes a piston down which opens the valve and allows high pressure air to flow to the pilot valve and the automatic valve operating pistons.

What controls the starting air valves on the cylinder of the main engine?

The opening of the main air start valves is controlled by a set of pilot valves located in the air start distributor, which in turn are timed to operate by a drive linked to the main camshaft. In the example shown, a small camshaft is used to control the opening and closing of the air start pilot valves.

How much air pressure does a marine diesel engine need?

Air starting system for marine diesel engine. Air at a pressure of 20 to 30 bar is required for starting main and auxiliary diesel engines in motorships and for the auxiliary diesels of steamships.

Why compressed air is used for starting the marine diesel engines?

Air Starting System Working Principle A Compressed air of 20 to 30 bar is required to start an engine by providing enough force to turn the engine at speed suitable to reach the combustion temperature and pressure.

What is MCR speed?

MCR is maximum continuous rating and is used for describing the specific fuel consumption or the daily fuel consumption when the ship is cruising at maximum speed. For the propulsion engine the speed and engine load are same or corresponding and hence these ratings. The ship is always operating at service speed.

What is MCR in engine?

Maximum Continuous Rating or MCR: It is the maximum power output engine can produce while running continuously at safe limits and conditions. It is specified on the engine nameplate and in the Technical File of the marine diesel engine.

What is the safety system in air starting line of main engine?

Different safety devices are installed on starting air line, inorder to prevent explosion. Bursting Disc It is installed on starting air pipe, between the manifold and the air starting valve. Flame Arrestor Flame arrestor helps to arrest any flame coming out of the cylinder through leaking start air valve.

What is the function of the air distributor?

What is the starting air distributor? It is the part of the starting air system responsible for providing pilot air to starting an air valve as per the correct starting order. For an idle six-cylinder engine; the injection timing of all cylinders is timed according to the firing order.

How do you start a marine diesel engine with starting air?

When the air start lever is operated in the ECR, the pilot valve shifts and blocks the air on top of automatic valve. It vents the line and there is no more positive closing. Air passed from turning gear interlock pushes the spring, opens the valve and closes the vent.

What is the function of control air in ship engines?

Control air plays a vital role in propulsion of ship and it is used for controlling the function of ship engines including

What is the function of the air control valve?

The idle air control valve (IAC) is usually connected to the throttle body next to the intake manifold. Consequently, it is the engine control unit (ECU) that manages all the functions of the valve. Based on the information it receives like engine load and temperature, it will change the speed of the idle accordingly.

What is the starting air in a marine diesel engine?

Starting Air System in Marine Diesel Engine. Normally, compressed air at 20 to 30 bar pressure is required to start an engine in a certain direction. The compressed air which is inserted to the cylinder is also termed as “starting air”. This starting air is inserted to a cylinder when it is just past the TDC; and end when the exhaust opens.

How does the pilot valve start the main engine?

To start the main engine, control air is given to the control valve which then sends air signals to the automatic valve to open. This leads compress air to the pilot and starting air valve. Now the pilot valve is under equilibrium by control and starting air at different sides of the piston in the pilot valve.