The Bosch injection system provides electronic control of the high pressure fuel pump and injection timing, as well as controls the operation of the exhaust gas reburning system (EGR) and glow plugs.
The system is controlled by an electronic control device (ECU), which receives signals from sensors that monitor engine load, engine speed, injector operation, and coolant temperature. The ECU controls the injection timing of the fuel pump and the operation of the EGR solenoid valve via the accelerator cable and vacuum diaphragm.
The Lucas EPIC injection system provides programmed electronic control of the high pressure fuel pump and electronic control of the exhaust gas reburning system through the electronic control unit (ECU).
The system is controlled by the ECU control unit from sensors for accelerator pedal position, intake manifold vacuum, engine speed and crankshaft position, coolant temperature and intake air temperature. The action of the EGR valve is also controlled by the ECU in conjunction with the solenoid valve.
A unique feature of this system is the accelerator control. Instead of an accelerator cable connected to a high pressure pump, the accelerator pedal is connected to a pedal position sensor. This sensor sends pedal position signals to the ECU, which in turn electronically controls the high pressure fuel pump.
Fuel system includes:
- fuel tank installed at the rear of the vehicle;
- fuel filter with separator;
- electronically controlled high pressure fuel pump;
- nozzles;
- connecting components.
Before fuel passes through the filter, the fuel is heated by coolant passing through the base of the fuel filter. A turbocharger and refrigerator are installed on all models.
Fuel from the fuel tank to the high pressure fuel pump is supplied by a centrifugal pump located in the high pressure fuel pump. A fuel filter is installed in front of the fuel pump, where the fuel is cleaned from foreign particles and water. Excess fuel lubricates the fuel pump and returns to the fuel tank through the pipeline.
The high pressure fuel pump rotates at half the speed of the crankshaft and is driven by a toothed belt from the crankshaft.
The amount of fuel supplied is controlled by a centrifugal governor, which responds to the position of the fuel control pedal and engine speed. The regulator is connected to a metering valve that increases or decreases the amount of fuel delivered for each pump cycle.
The moment of fuel injection is determined by the pump. When the engine is running, the fuel injection timing is changed automatically in the pump by the ECU system.
Four fuel injectors spray fuel into swirl chambers located in the cylinder head. The nozzles are calibrated in such a way that they open and close at a strictly defined pressure, which ensures efficient and complete combustion of the fuel. Each injector needle is lubricated with fuel that accumulates in the space near the spring and then flows to the return hose.
Starting a cold engine is facilitated by the presence of glow plugs installed in each swirl chamber. On the Bosch system, the idle speed of a cold engine is increased by vacuum acting through the diaphragm on the accelerator cable. On the Lucas system, idle speed is automatically controlled by the fuel pump. Both systems are controlled by the ECU.
The engine stop solenoid shuts off the fuel supply to the fuel pump rotor when the ignition is turned off. The Bosch high pressure fuel pump also has an engine stop lever.
A well-maintained fuel pump can last longer than an engine before repairs. The main cause of damage to the fuel pump and injectors is dirt or water in the fuel.
Maintenance of the fuel pump and injectors is very difficult. Therefore, it must be produced at the Peugeot station.
Additional precautions must be observed when working on the Lucas injection system:
- always disconnect the negative battery terminal before disconnecting any of the fuel system connectors;
- when installing the battery, do not reverse the poles;
- do not expose system components (especially the ECU) blows;
- do not open the ECU;
- prevent moisture from entering the electronic control system components (when washing the engine, protect the system from water ingress).