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Application Engineering Bulletin Subject: QST30 Electric Fuel Supply System This AEB is for the following applications: Automotive Industrial Power Generation Date: September, 2002 Page 1 of 12 AEB Number 70.30 Author: Curtis Kwasniewski Engine Models included: QST30 Fuel Systems included: Bosch P7100, Bosch P8500-LLA, Bosch RP39 Table of Contents: Section Page Purpose 2 Scope 2 Background 2 Construction 3 Electric Fuel Supply Pumps 3 Combo Fuel Filter Head & Pump Manifold 4 FS1006 Fuel Filter with Water Separator 4 Fuel Manifold with Integrated FSO Valve 5 Fuel Connections 5 Pre-filters 6 Wiring with EFS Power Relay 6 Pressure and Temperature Sensors 6 Operation 7 Advantages 8 Appendix 1 (System Specifications) 9 Appendix 2 (System Diagrams) 10 2 Purpose: The purpose of this document is to discuss the construction, operation, and advantages of the Electric Fuel Supply System. Scope: This document applies to QST30 engines, both Generator Drive and Industrial. Background: The QST30 fuel systems require small pumps to draw fuel from the fuel tank and deliver it through the fuel filters to the injection pumps at approximately 35psig. All engines built prior to March of 2002 included two mechanically driven plunger lift pumps that were attached to the sides of the Bosch fuel injection pumps. In March 2002 Cummins Inc. will introduce a new system that uses two electric roller-vane pumps that are integrated into the fuel filter head (see Figure 1) to replace the mechanically driven lift pumps. The new system is called the Electric Fuel Supply (EFS) system and it offers significant benefits for operation and service of the QST30 engine. The EFS will not entail any change in engine envelope. Figure 1: EFS system flow diagram 3 Construction: The EFS system consists of the following components: • Electric Fuel Supply Pumps • Combination Fuel Filter Head and Pump Manifold • FS1006 Fuel Filter with Water Separator • Fuel Manifolds with Integrated Fuel Shut-off (FSO) Valves • Fuel Fittings and Connections • Wiring with EFSS Power Relay • Pressure and Temperature Sensors System specifications are detailed in Appendix 1. Electric Fuel Supply Pumps Two electric pumps are used in parallel to deliver fuel from the fuel tank through the filter to the fuel injection pumps. The two pumps are mounted in the fuel filter head and they both discharge into a single fuel filter (see Figure 2). The pump set is capable of pumping 1000 lbs/hr (454 Kg/hr) of fuel at 40 psi (276 kPa). The two pumps are wired in series so that they can be powered by a 24V supply but each pump will operate at 12V. Please be aware that the electric fuel supply pumps will draw 6 to 8 amps from the batteries at all times while the engine is running. Figure 2: EFS Filter Head Top View 4 Combo Fuel Filter Head & Pump Manifold The fuel filter head for the EFS system holds the two electric fuel supply pumps as well as the FS1006 fuel filter (see Figure 3). The head also has ports to hold the fuel inlet fitting and the fuel pressure and temperature sensors (optional). FS1006 Fuel Filter with Water Separator The QST30 fuel supply system was originally designed to use two FF202 fuel filters. The FS1006 filter includes the Fleetguard StrataPoreTM synthetic media that improves filtration efficiency, contaminate capacity and media life. The FS1006 filter is efficient at removing contaminates as small as 10 micron which helps to protect the fuel injection pumps from wear. The StrataPoreTM media also provides 95% water separation efficiency. The excellent characteristics of the FS1006 filter and the steady pressure supply of the electric fuel pumps make it possible to achieve 500 hour change intervals with a single filter element compared to the two elements that were required for the original fuel supply system design. Figure 3: EFS Filter Head Assembly 5 Fuel Manifold with Integrated FSO Valve The EFS system includes a fuel manifold on each side of the engine. The fuel manifolds are used to distribute fuel to the injection pumps and direct overflow fuel back to the fuel tank (see Figure 4). Each manifold has a built-in fuel shut-off (FSO) valve. The FSO is a solenoid operated valve that prevents fuel flow to the injection pumps when the engine is not running or when a shutdown command is received. One of the two fuel manifolds contains a bypass valve that will relieve pressure in excess of 80 Psi (552 kPa) directly to the return line. The return fuel flow from the injectors passes through the manifold before returning to the fuel tank by a common header. Fuel Connections Fuel connections to the various components of the electric fuel system are made using banjo connectors. The connections have been sized to avoid confusion. All pressurized supply connections are M16 banjo connectors and all drain connections are M14 or M8 banjo connectors. Figure 4: Fuel Manifold Detail 6 Pre-filters The electric fuel system requires the use of a 140-Micron (maximum) pre-filter. This pre- filter should be installed prior to the fuel inlet to the filter-head. Option FS5033 or equivalent. Wiring with EFS Power Relay The power to the electric fuel supply pumps is supplied from the 24V batteries through a power relay (see Figure 6). The circuit for the EFS power relay may either be contained in an external jumper harness that is added to the engine (Part Number 4068049) or it may be integrated into the base-engine harness (3093696 for Generator Drive engines, 4067866 for Industrial engines). On industrial engines the signal for the power relay comes directly from the keyswitch so that whenever the keyswitch is “on” the electric pumps will also be “on”. For Generator Drive engines using the GCS controller and the INPOWER service tool, the signal to the power relay comes from the ECM, so the pumps are energized whenever the generator is commanded to start. Wiring for the EFS is built into the engine wiring harness for these engines. No additional customer interface is required for these engines. Corporate Generator Sets and Generator Drive engines using the INSITE service tool will use the jumper harness with the EFS. No interface changes will be required for Corporate Generator Sets. Engines using the INSITE service tool will require OEMs purchase and install the jumper harness to use the EFS. Power to the EFS relay, in jumper harness equipped engines, will be provided by the signal to the FSO valves. When the FSO valves are commanded to open the EFS will be energized. The fuel pumps are wired in series so that two 12V pumps can be powered from a 24V supply. Please be aware that the electric fuel supply pumps will draw 6 to 8 amps from the batteries at all times while the engine is running Pressure and Temperature Sensors Industrial and Generator Drive engines with the new version of the base-engine wiring harness (3093696 for Generator Drive engines, 4067866 for Industrial engines) will include a pressure sensor and a temperature sensor for the fuel supply. The sensors will be mounted into the fuel filter head (see Figure 7). The fuel supply temperature sensor will be in the flow path immediately after the fuel supply pumps and immediately before the fuel filter. The fuel supply pressure sensor will be in the flow path immediately after the fuel filter. This arrangement will allow the ECM to detect low system pressure due to plugged filters. Figure 6: EFS Power Relay Circuit 7 Operation When the ECM detects a start condition (for Generator Drive) or when the key switch is in the “on” position (for Industrial) the relay energizes. When the relay is energized the pumps are powered. With the relay energized the pump set delivers fuel to the injection pumps until the engine is shut down. In the event of short-circuit an integrated 20 amp fuse will open to prevent damage. If the ECM commands a shut down (either planned or unplanned) the power to the FSO solenoid is interrupted. On industrial engines the electric pumps will continue to pump until the keyswitch is turned “off” but with the FSO valves closed there will be no fuel flow to the injection pumps. On Generator Drive engines, when the power to the FSO valves is interrupted the power relay will also de-energize and the electric pumps will stop. Figure 7: Fuel Filter Head Detail 8 Advantages The Electric Fuel Supply System has the following advantages. • Less Complex Fuel Lines: Because the FSO valves are integrated into the fuel manifold and the lift pump and fuel filter are combined in a single filter head, the number of fuel lines is dramatically decreased and simplified. Fewer fuel lines will reduce the possibility of leaks and simplifies trouble-shooting and repair. • Consistent Fuel Flow at All Engine Speeds: Because the speed of the electric lift pump is independent of the engine speed it supplies a constant fuel flow to the injection pumps at all engine speeds. This results in higher fuel pressures at starting which leads to better starting characteristics and a smoother running engine at low speeds. • Improved Filtration: The FS1006 fuel filters offer superior protection for the engine. Use of the electric fuel supply pumps allows a single FS1006 filter to accommodate the entire fuel flow for the engine. The Stratapore media used in the FS1006 filters allows for extended filter service intervals. • Simplified Trouble-Shooting and Service: The electric lift pump has fewer parts and a much simpler design. With fuel line connections that are sized to minimize confusion and a single fuel filter the service of the system becomes greatly simplified. The electric pumps can be energized while the engine is not running so that problems with the fuel supply system can be diagnosed independently. • Provisions for Priming the Fuel System: The electric fuel supply pumps can be energized before the engine is started. This will fill the fuel system and bring it up to pressure before the engine is cranked. Priming the fuel system will improve the first injection events making the engine easier to start. Additionally, if the fuel system is drained for any reason (such as fuel filter change) purging air from the system is simplified by energizing the pumps. 9 Appendix 1: System Specifications Electrical: Operating Voltage: 24 VDC System (12VDC Individual Pumps) Current Draw: 6 Amps (Total) Fuse Rating: 20 Amps Pressures: Pump Suction: 20 “Hg max (381 mm Hg) Pump Discharge: 40 psi (276 kPa) Bypass Set Point: 80 psi (552 kPa) Maximum Static Head 14” Hg max (356 mm Hg) Flow of Pump Set: Mass Flow Rate: 1000 lbs/hr (454 kg/hr) Vol. Flow Rate: 140 gph (636 l/hr) Filtration: Filter media size: 10 micron Water Separation Efficiency: 95% Connections: Customer Fuel Inlet Connection: 1-1/16 inch (27 mm) Customer Fuel Outlet Connection: 7/8 inch (22 mm) Appendix 2: System Diagrams QST30 Electric Fuel Supply System System Detail 12 Fuel Filter Head Component Exploded View Pressure Sensor Temperature Sensor Filter Adapter Filter Head Pump Head Fuel Filter Fuel Inlet Fitting Fuel Pumps a temperature sensor for the fuel supply. The sensors will be mounted into the fuel filter head (see Figure 7). The fuel supply temperature sensor will be in the flow path immediately after the fuel supply pumps and immediately before the fuel filter. The fuel supply pressure sensor will be in the flow path immediately after the fuel filter. This arrangement will allow the ECM to detect low system pressure due to plugged filters. Figure 6: EFS Power Relay Circuit 7 Operation When the ECM detects a start condition (for Generator Drive) or when the key switch is in the “on” position (for Industrial) the relay energizes. When the relay is energized the pumps are powered. With the relay energized the pump set delivers fuel to the injection pumps until the engine is shut down. In the event of short-circuit an integrated 20 amp fuse will open to prevent damage. If the ECM commands a shut down (either planned or unplanned) the power to the FSO solenoid is interrupted. On industrial engines the electric pumps will continue to pump until the keyswitch is turned “off” but with the FSO valves closed there will be no fuel flow to the injection pumps. On Generator Drive