Marine Diesel Engine Components and Functions - Vocabulary Flashcards

A set of vocabulary-style flashcards covering key marine diesel engine components and their functions, drawn from the lecture notes.

Bedplate

The engine’s foundation that supports weight, provides crankshaft alignment, distributes loads, collects oil, and transfers thrust. Types include cast iron bedplates and welded steel bedplates.

A-frame and entablature

Structural supports for the engine: the A-frame holds the crankshaft and auxiliary components, while the entablature spans the top to mount and distribute weight, aiding vibration isolation.

Guides

Engine guides (2-stroke) that direct and constrain piston-rod movement to maintain alignment and reduce wear.

Cylinder block

The main housing that contains the cylinders; backbone of the engine providing mounting for crankshaft, connecting rods, and pistons.

Cylinder liner (wet)

A replaceable metal sleeve inserted into the bore and cooled by coolant, providing a wear surface.

Cylinder liner (dry)

A sleeve not in direct contact with coolant; cooled by lubricating oil rather than coolant.

Cylinder head

Top cover of the cylinder block that houses the valves, combustion chamber, and injectors, with passages for coolant and oil.

Turbocharger

Device that increases engine power by forcing more air into the cylinders via a turbine driven by exhaust gas.

Turbocharger arrangements

Different exhaust-turbine configurations: constant pressure, impulse, pulse converter, and multi-pulse to shape performance.

Scavenge trunk

In a two-stroke engine, passage directing exhaust out and drawing in fresh air/fuel into the cylinder.

Air cooler

Charge air cooler that lowers temperature of compressed air from the turbo to increase density and efficiency.

Air blower

Device that forces air around the engine; types include axial flow, airfoil centrifugal, and radial blowers.

Crankshaft

The engine’s rotating heart; converts linear piston motion to rotary motion and transmits power while supporting bearings.

Connected rod

Link between the piston and the crankshaft that transfers piston force to the crank.

Piston rod

Rod that connects the piston to the small end of the connecting rod, transmitting force.

Crosshead

Guide for large engines that provides linear motion for the piston rod and can transmit thrust.

Piston (Crosshead type)

A piston used with a separate piston rod and crosshead arrangement.

Piston (Trunk type)

A piston whose rod is integrated with the piston itself (trunk type).

Piston rings (Compression ring)

Seals combustion chamber by preventing gas leakage between piston and bore; usually tapered for a tight seal.

Piston rings (Scraper ring)

Wipes excess oil from the bore to control oil consumption and reduce oil-fouling of the combustion chamber.

Main bearing

Supports the crankshaft within the engine block and allows smooth rotational motion.

Crankpin bearing

Supports the connecting rods on the crankpin, transmitting force and enabling smooth rotation.

Crosshead bearing

Supports the crosshead on large engines, providing a low-friction sliding surface.

Thrust bearing

Resists axial movement (thrust) of the crankshaft, helping to control endplay.

Fully built crankshaft

Crankshaft assembled from multiple components for flexibility in construction and repair.

Semi-built crankshaft

Partially assembled crankshaft combining forged and cast components for balance of strength and cost.

One-piece crankshaft

Crankshaft forged from a single piece for maximum strength and rigidity.

Camshaft

Timing device that controls the opening/closing of intake and exhaust valves, coordinating with piston motion.

Push rod

Linkage in OHV engines that transmits camshaft motion to the rocker arm and valves.

Rocker

Rocker arm that transfers camshaft motion to the valve, providing motion amplification.

Intake valve

Valve that allows air/fuel into the combustion chamber.

Exhaust valve

Valve that allows exhaust gases to exit the combustion chamber.

Air inlet ports

Openings that admit air into the cylinder or intake manifold.

Stuffing box

Seal between the crankcase and scavenge space to prevent oil/gas mixing.

Chain/ Belt/ Gear drive

Different systems to transmit mechanical power between shafts; each has distinct advantages.

Fuel pump

High-pressure pump delivering fuel from tanks to cylinders with precise timing.

Fuel injector valve

Delivers a precise amount of fuel into the combustion chamber at the correct time.

Starting air valve

Valve that provides a burst of compressed air to cylinders during starting.

Cylinder relief valve

Safety valve protecting the cylinder from excessive pressure buildup.

Crankcase relief valve

Valve regulating pressure within the crankcase to prevent buildup.

Flywheel

Stores rotational energy to smooth engine speed and dampen fluctuations; attached to the crankshaft.

Vibration damper

Device that absorbs torsional vibrations to reduce noise and engine movement.

Exhaust gas manifold

Collects exhaust from cylinders and channels it into the exhaust system.

Air-inlet manifold

Distributes incoming air to the engine’s cylinders for combustion.

Air system

System for compressing, storing, and distributing high-pressure air (including starting air) in the engine.

Lubricating oil system

System that delivers lubrication to moving parts; includes pump, filters, coolers, and sumps.

Cooling water system

Circulates coolant to remove heat and prevent overheating.

Engine turning with turning gear

System used to rotate a stopped main engine for maintenance and positioning.

Slow turning on starting air

Slow rotation to distribute lubrication and remove fluids before starting, without fuel ignition.

Fuel oil system

System delivering fuel oil to the engine, including tanks, pumps, filters, and injectors.

Crankcase

Housing for the crankshaft and connecting rods; reservoir for lubricating oil and structural support.

Lubricating oil sump tank

Oil reservoir that ensures a constant oil supply to vital components.

Gudgeon pin

Pivotal connection between the piston and the connecting rod.

Governor

Speed-regulating device that adjusts fuel delivery to maintain target engine speed; mechanical or electronic.

Start Air System

System providing compressed air to start the engine, including receivers and compressors.

Piston crown

Top part of the piston forming the combustion chamber.

Piston skirt

Lower portion of the piston that guides within the bore and helps seal.

Piston pin

Connecting link (piston pin) between the piston and linking rod.

Piston (general)

Moving component inside the cylinder that transmits piston pressure via rings to the crankshaft.