Fuel Pumps Repair and Service
Need a diesel fuel pump to be tested, repaired, or to have a new one supplied, Raglan Diesel Injection can help.
Rotary Distributor Pumps
Distributor pumps have provided the diesel engine with wider application in automotive, agriculture, and heavy-duty equipment application by significantly reducing the cost, size and weight of diesel engines.
Distributor pumps – although surpassed by electronic unit injection and common rail systems – are still very much in use in both on- and off-road applications.
Unlike inline pumps or unit injectors, which use a separate fuel pressurization element for each cylinder, distributor pumps make use of a single pumping element to deliver fuel to all cylinders.
This configuration greatly reduces the number of parts making for an economical, compact pump.
Other fuel components such as the governor, fuel transfer pump and injection timing mechanisms are built into the pump body, which allows for increased production efficiency.
For decades, the most popular diesel engine fuel injection system was the inline pump – also known as the multiple plunger fuel injection pump. This rugged, durable, compact fuel system enabled diesel engine design to transition from its original use in large stationary, applications to on-road and heavy-equipment service.
An inline pump is a fuel system configuration that uses a piston-like barrel and plunger assemblies that are actuated by a camshaft to pressurize fuel for injection. To vary the quantity of fuel required for injection, a port-helix metering system accurately meters the fuel used for each injection event. There is a pumping element, consisting of a barrel and plunger arranged inline in a pump housing, corresponding to each engine cylinder.
One of the smallest pumps, the flange pump uses the same principles as an inline pump, also delivering fuel by means of rollers compressing a spring and causing fuel to be delivered. Unlike an inline pump however, a flange pump is governed by a governor attached to the motor itself, which is linked to the flange pump via the flange pump's rack.
A unit pump system (UPS) combines elements of pump-line-nozzle (PLN) injection system and unit injectors. Each cylinder uses a separate camshaft-driven high-pressure pump to pressurize fuel for injection. Connecting the pump to the nozzle is a high-pressure fuel line. The pump operates using principles like the unit injector.
Unit pump injection systems have allowed for the adaptation of high-pressure electronically controlled injection systems to engines previously using inline pump injection systems without extensive engine modification. The supply fuel pump delivers fuel at low pressure to the fuel filter, then to the individual fuel injection pumps. A fuel return line collects unused fuel circulating through the pumps and empties it back into the fuel tank.
Common rail is the latest innovation in high-pressure injection systems and is currently used by the majority of diesel engines. Its concept is simple: supply fuel at injection pressure to a fuel nozzle that electrically controls the injection event. Its features and benefits have made it the injection system of choice for all light, medium, and even most heavy-duty on-road engines.
Common rail pumps are high pressure fuel pumps which develop the pressure required for injection under all engine operating conditions, including quick starting of the engine. Low cost single-plunger pumps are typically used in small displacement four-cylinder engines, while two, three, and even four-cylinder pumps are used in engines with higher fuel volume requirement. These pumps are cam actuated using inlet and outlet valves to control pump flow.
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