Intro to marine engineering DA taylor 2e (1996)

[...]... using a torsionmeter or with a brake The engine indicator An engine indicator is shown in Figure 2.8 It is made up of a small piston of known size which operates in a cylinder against a specially 16 Diesel engines Piston rod Calibrated spring Drum Linkage to provide straight line movement of stylus Piston Cylinder Indicator piston Section showing indicator piston ^vindicator cord —I Coupling *—' nut to. .. system Fuel injector HTuel pumps eated filter 22 Diesel engines After passing through centrifuges the cleaned, heated oil is pumped to a daily service tank From the daily service tank the oil flows through a three-way valve to a mixing tank A flow meter is fitted into the system to indicate fuel consumption Booster pumps are used to pump the oil through heaters and a viscosity regulator to the engine-driven... strokes of the piston, or two revolutions of the crankshaft In order to operate this cycle the engine requires a mechanism to open and close the inlet and exhaust valves Consider the piston at the top of its stroke, a position known as top dead centre (TDC) The inlet valve opens and fresh air is drawn in as the piston moves down (Figure 2.1 (a)) At the bottom of the stroke, i.e bottom dead centre (BDC),... Adjustments may then be made to the fuel supply in order to balance the cylinder loads Torsionmeter If the torque transmitted by a shaft is known, together with the angular velocity, then the power can be measured, i.e shaft power = torque x angular velocity The torque on a shaft can be found by measuring the shear stress or angle of twist with a torsionmeter A number of different types of torsionmeter are described... temperature) as the piston rises (Figure 2.1(b)) Fuel is injected as the piston reaches top dead centre and combustion takes place, producing very high pressure in the gases (Figure 2 l(c)) The piston is now forced down by these gases and at bottom dead centre the exhaust valve opens The final stroke is the exhausting of the burnt gases as the piston rises to top dead centre to complete the cycle (Figure... into a manifold or rail which is maintained at high pressure From this common rail fuel is supplied to all the injectors in the various cylinders Between the rail and the injector or injectors for a particular cylinder is a timing valve which determines the timing and extent of fuel delivery Spill valves are connected to the manifold or rail to release excess pressure and accumulator bottles which dampen... up, the ports at B are closed and the fuel is pressurised and delivered to the injector nozzle at very high pressure When the edge of the helix at C uncovers the spill port D pressure is lost and fuel delivery to the injector stops A non-return valve on the delivery side of the pump closes to stop fuel oil returning from the injector Fuel will again be drawn in on the plunger downstroke and the process... high-pressure fuel to their respective injectors The viscosity regulator controls the fuel oil temperature in order to provide the correct viscosity for combustion A pressure regulating valve ensures a constant-pressure supply to the engine-driven pumps, and a pre-warming bypass is used to heat up the fuel before starting the engine A diesel oil daily service tank may be installed and is connected to the system... port (Figure 2.3(b)) The burnt gases then begin to exhaust and the piston continues down until it opens the inlet or scavenge port (Figure 2.3(c)) Pressurised air then enters and drives out the remaining exhaust gas The piston, on its return stroke, closes the inlet and exhaust ports The air is then compressed as the piston moves to the top of its stroke to complete the cycle (Figure 2.3(d)) A timing... Coupling *—' nut to fasten onto indicator cock Figure 2.8 Engine indicator calibrated spring A magnifying linkage transfers the piston movement to a drum on which is mounted a piece of paper or card The drum oscillates (moves backwards and forwards) under the pull of the cord The cord is moved by a reciprocating (up and down) mechanism which is proportional to the engine piston movement in the cylinder . h1" alt="" Introduction to Marine Engineering This page intentionally left blank Second Edition Introduction to Marine Engineering D. A. Taylor, MSc, . 1946- Introduction to marine engineering 2nd ed. 1. Marine engineering I. Title 623.87 Library of Congress Cataloguing in Publication Data Taylor,