Lucas DPC Diesel Injection Pump: Technical Operation

Lucas DPC Diesel Pump: Technical Operation

Transfer Pump

The Lucas DPC diesel transfer pump introduces fuel into the rotor through a pressure-regulating valve. It receives and distributes fuel using two plungers that slide along a cam ring. The fuel quantity depends on the position of the metering valve, which is operated by the throttle and the regulator.

Transfer Pressure

The pump draws fuel and sends it to the pumping element. Transfer pressure is maintained from the transfer pump to the dispensing valves.

Pressure Control Valve

This component controls pressure and initiates the circuit. It consists of a piston and a regulation spring, which is adjusted by a locking screw nut.

Dosage, Pumping, and Distribution

These functions are performed by the hydraulic head, which is formed by the head, the rotor, and a metering valve that controls flow to the pistons.

Regulator

The regulator consists of centrifugal weights mounted on a support integral with the shaft.

Variable Advance

Located at the top of the cam ring, this system uses a piston within a sleeve that communicates with the cam ring via a ball joint. Two springs control the piston movement when subjected to transfer pressure.

Overload Mechanism

This increases fuel flow during initial engine revolutions to facilitate starting. When the engine is off, a spring pushes the brake shoes to increase the displacement of the plungers. Once running, a valve releases the pressure acting on the pistons, allowing the plungers to return to their normal position.

Light Load Advance

This adjusts the injection timing when the engine runs at idle. It consists of a pressure piston that receives input from the throttle valve. At idle, the piston is subjected to internal pressure, providing a slight advance in injection.

Electromagnetic Cold Start Advance

This system advances the injection timing during cold engine operation to reduce exhaust fumes. It consists of an electromagnet with a rod in contact with the advance piston. During the cold idle phase, the electromagnet is powered, driving the rod and the cam ring to the advance position.

Turbo Charger Connector

This adjusts fuel flow based on turbocharger pressure. It comprises a piston supported by a core with a membrane on each side, which receives boost pressure. It is mounted on the transfer pressure circuit between the valve and the overload device.

Electric Stopping Device

This device is threaded into the hydraulic head and is located in the channel that feeds the metering valve.