VP44 Electronic Inj Pump
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VP44 Injector Pump System
Visit Geno's Garage for Truck accessories. accessories. The VP44 injection pump pump was introduced on the Cummins ISB as a stop gap measure to meet 1998 emissions standards before a common rail fuel system was ready for production. For Dodge Ram pickups, the ISB engine was used in all trucks built after January 1, 1998. A common rail system is being road tested now, and reliable rumors say the the VP44 will be replaced by a common rail rail in 2003 models. models. For those with 1998-2002 Rams, here are some details about the VP44 pump. To meet environmental regulations regulations for a variety of engine applications, applications, Cummins designed an ECU to which they could download different engine control programs without making making any physical changes to the engine. This electronic engine control unit (ECU) is installed in a sealed box that that is mounted directly directly to the cylinder block of the engine. The
VP44 Electronic Inj Pump
needed for direct-injection, The VP44 uses an internal cam disk and radially opposed plungers to pressurize the fuel from two directions. The VP44 controls the injection rate and injection timing using two electromagnetic valves. Also, the electronic control unit is divided into two, with a compact control unit mounted directly on the pump and a larger Engine Control Module mounted on the engine block.
Fuel System - General Information from Cummins
The VP44 is an electronic fuel injection pump manufactured by Bosch®, that can vary fueling and injection timing based on input from the electronic control module (ECM). This pump has its own electronic control unit, the fuel pump control module (FPCM), which contains fueling, timing, and diagnostic data. The fuel pump control module (FPCM) communicates with the engine controller (ECM) to obtain information on desired fueling and timing. The fuel pump control module (FPCM) responds to the ECM's commands by consulting the fueling data and timing in its memory and actuating the fueling and timing solenoids. A fuel temperature sensor is located inside the VP44 pump to compensate for changes in the temperature of the fuel. The pump also contains a speed sensor (IAT) that gives the fuel pump control module (FPCM) data on the position and speed of the pump shaft. A reference pulse that marks top dead center (TDC) of cylinder No. 1 is sent from the ECM
VP44 Electronic Inj Pump
building injection pressure. By rotating the cam ring with the timing solenoid, the fuel pump control module (FPCM) is able to advance and retard the injection timing by making the rollers contact the cam lobes either earlier or later. The second solenoid in the pump is used to meter fuel to the injectors. The solenoid opens the fuel metering valve to allow fuel from the supply pump to flow into the pumping chamber. Once the pumping chamber is charged with fuel, the solenoid valve closes. This traps the fuel in the chamber and allows injection pressure to build. The fuel is routed to the correct injector by the pump distributor. The distribution port on the distributor aligns with one of the six outlet ports to distribute fuel to a given injector. Once the desired amount of fuel has been injected, the solenoid valve opens, causing the pressure in the pumping chamber to bleed down, which ends injection. The cycle then begins again for the next cylinder. The fuel injection pump (VP44) is an electronic rotary distributor pump. The pump performs four basic functions: 1. 2. 3. 4.
Producing the high fuel pressure required for injection Metering the exact amount of fuel for each injection cycle Distributing the high-pressure, metered fuel to each cylinder at the precise time Varying the timing relative to engine speed.
A cam ring with three plungers, a rotor, and an electronically controlled fueling solenoid valve is used to develop and distribute the high pressure required for injection. A worn or damaged internal transfer pump, plunger, or fueling valve can affect the pressure and the amount of fuel injected, thus reducing the power from the engine. Generally, if the fuel-injection pump is injecting fuel from one outlet, it will deliver from all outlets. VP44 Timing Principles
VP44 Electronic Inj Pump
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Subject: [TD] VP44 & P7100 Date: Fri, 11 Jun 1999 08:19:36 -0700 From: Josh Berman
[email protected] To: TurboDiesel, cummins > I was told the rotary pump on the ISB's does not have near the capacity of the > older in line pumps. One cylinder versus six. Just does not have the ability > to move as much fuel apparently.
The VP44 that we use actually has 3 pistons arranged in a radial pattern (think of the "star" logo on a line of German luxury cars :-). BOSCH makes VP44s with different #'s of pistons, depending on how many cylinders the engine has. The pistons ride inside a cam ring (think of a doughnut with a lumpy hole). As the pump shaft rotates, the pistons rotate inside the cam ring, and the ramps on the cam ring press the pistons inward, pressurizing the fuel (which is then directed through the fueling solenoid and distributor which sends the fuel to the correct cylinder). The P7100 can pump a lot of fuel: it went to 230 HP on the B-Series automotive engine, 325 on the C-Series automotive engine, even higher on the marine versions. Currently, the highest rating we sell the ISB (and thus the VP44) at is 275 HP. That rating is
