DIESEL FUELS & DIESEL FUEL SYSTEMS

Application and Installation GuideDiesel Fuels & Diesel Fuel SystemsIn many cases, the auxiliary pumpwill be driven by an electric motorand therefore needs a regulatorvalve so that the fuel flow canmatch the engine speed.Example:A power plant with one (1) 3516Bdiesel generator set, rated for 1145bkW (1560 bhp) at 100% load. Thefuel rate for the engine is 284 L/hr(75 G/hr) as found in TMI.The time between tank refills isbased on weekly fuel tanker truckdeliveries, so refill time is 168 hours.The fuel tank for this genset islocated 22 m (72.2 ft) horizontallyand 2.5 m (8.2 ft) vertically (below)from the engine. This situationexceeds the fuel systemrequirements discussed in AuxiliaryFuel Tanks, therefore, an auxiliarypump is needed.Solution:TMI indicates that the fuel flow atrated speed is 1260 L/hr (333 G/hr)@ 1200 rpm.The auxiliary transfer pumprequired for this sample installationmust be able to deliver fuel at 1260L/hr (333 G/hr) at a pressure of 34.5kPa (5 psi).EmergencyMany marine applications requirethe capability to connect anemergency fuel oil transfer pumpinto the engine’s fuel oil system.Caterpillar engines can be providedwith these optional connectionswhen necessary.This is a specific requirement ofmarine classification societies forseagoing single propulsion engineapplications. The purpose is toensure fuel oil supply in the event ofan engine fuel oil pump failure. Theemergency fuel oil pump allows thesingle propulsion engine to operateand the ship to reach port for enginerepairs.Guidelines for emergency fuel oilsystem operation:1. Keep pressure drops to aminimum by using short, lowrestrictionlines.2. Use a line size at least aslarge as the engine connectionpoint.3. Install a low-restrictionstrainer in front of the emergencyoil pump.4. Install a low-restriction checkvalve between the emergencypump discharge and the engineinlet connection.5. Use a pressure-limiting valvein the emergency system set atthe maximum oil pressure limit ofthe engine.6. TMI contains flow rates andpressure limits to fulfill minimumengine requirements for fullpower at rated speeds forCaterpillar engines.Fuel Piping DesignConsiderationsFuel Supply PipingUsing shutoff valves in the deliveryline may pull air into the systemduring shutdown and cause hardstarting. The engine control systemprovides adequate shutdownoptions, but, if a shutdown solenoidis specified in the supply line, it©2005 Caterpillar®All rights reserved. Page 21