The 2.1 liter XUD11BTE/L3 engine is equipped with Lucas' EPIC fuel injection system. The injection pump of this engine has fuel control valves, a fuel injection timing adjustment solenoid valve, a fuel cut-off valve and various sensors, including a fuel temperature sensor, a distribution rotor and cam position sensor.
The letter L in the engine designation means that this engine does not have a catalyst, Y means a complete set with a catalyst, and L3 indicates the degree of harmful substances in the exhaust gas and compliance with the standards adopted in the EU.
Vehicles with a DK5ATE engine have a Bosch MSA 11 3 6 VP36 power system.
In diesel engines, air enters the combustion chambers of the cylinders and is highly compressed there. Because of this, the temperature in the cylinders becomes higher than the ignition temperature of diesel fuel. At the moment when the piston of the cylinder is almost at top dead center, diesel fuel is injected into the air, compressed and heated to +600-700°C. The fuel is self-igniting, so spark plugs are not needed.
With a very cold engine, compression alone will not reach the ignition temperature. In this case, the engine must be preheated. To do this, each combustion chamber has a glow plug that preheats the chamber. The warm-up time depends on the ambient temperature and is controlled by the engine control unit via the preheat relay.
Preheating and maintenance functions the same on all engines. The regulator that controls the operation of the preheating and tracking unit acts as a relay, from which power is supplied to the preheating candles. The glow plugs, as well as the control lamp of this device, are supplied with power at the moment the ignition is turned on, if the temperature of the coolant is below 60°C. After a while, the regulator cuts off the voltage supply to the pre-heating plugs. At the same time, in the engine start phase, power is supplied to the candles and their glow continues for some time after the start.
Accompanying preheating means that the plugs continue to be in the glow phase after the engine is started. Accompaniment begins immediately after the engine is started and the starter is turned off. During the first 15 seconds, the voltage supply to the glow plugs cannot be interrupted. After 15 seconds, the power supply may be cut off if the coolant temperature is above 60°C or if the accelerator pedal is in a certain position or pressed for more than a programmed time.
To reduce the content of harmful substances in the exhaust gases, a so-called unregulated catalyst is installed on modified engine models. A further reduction in the amount of nitrogen compounds in the exhaust gases is provided by the exhaust gas recirculation system by diverting part of the exhaust gases for re-burning and mixing it with the intake atmospheric air. The volume of exhaust gases returned for post-combustion needs to be dosed because their uncontrolled intake leads to the formation of soot and an increase in the content of particulate matter in the exhaust gases. All engines are equipped with an exhaust gas recirculation system, regardless of whether a catalytic converter is installed or not. The exhaust gas recirculation system reduces the emission of harmful substances into the atmosphere by directing part of the exhaust gas into the intake manifold. Exhaust gas recirculation only takes place under certain conditions, depending on the coolant temperature and the engine load. The coolant temperature sensor in the outlet pipe provides the appropriate signal for the coolant temperature. Exhaust gas recirculation occurs when the engine reaches a temperature above 60°C, and the load on the engine does not exceed the nominal load value set in the load sensor attached to the high-pressure fuel pump. The control unit opens the EGR solenoid valve, which regulates the operation of the entire EGR system. At the same time, the vacuum pressure generated by the vacuum pump located on the camshaft opens the mechanical exhaust gas valve installed on the exhaust manifold, and part of the exhaust gas is discharged into the intake manifold.
When the engine is running at low speeds, the low pressure generated by the vacuum pump reaches its maximum. The mechanical exhaust gas valve then remains open, diverting the exhaust gas to the intake manifold. Exhaust gas circulation is maintained by a pressure difference between the intake and exhaust manifolds, determined by the throttle valve, which closes almost completely.
As the engine accelerates and revs up, the low pressure generated by the vacuum pump drops and the mechanical exhaust gas valve is gradually closed by spring action, reducing the amount of exhaust gas sent to the intake manifold. At the same time, the throttle valve opens to let in more fresh air.
The diesel engine control unit recognizes faults and malfunctions in the power system and registers them, creating an error log, where faults are recorded in the form of codes. In the workshop, using a tester connected to the diagnostic socket, the log can be printed or read in order to purposefully eliminate the recorded malfunctions without wasting time and effort searching for them.
Before entering the high pressure fuel pump, the fuel passes through the fuel filter. Contaminants and condensate are retained in the filter, so it is extremely important to change the fuel filter or remove condensate from it in a timely manner. The injection pump does not require maintenance. All moving parts of the pump are lubricated with diesel fuel.
The required volume of injected fuel is determined and set by the microprocessor, which regulates the duration of the opening of the valve injectors. Electromagnetic fuel injectors are individually controlled by the electronic control unit, while the injectors inject fuel directly into the combustion chambers.
The crankshaft position sensor transmits signals to the electronic engine control unit, allowing you to correctly determine the moment of fuel injection.
The accelerator pedal position sensor potentiometer provides pedal position information to the engine control module.
To increase passive safety, cars are equipped with a safety sensor (switch), triggered in the event of a sudden forced stop of the car, as happens in a collision, and turns off the fuel pump. The switch can be returned to its working position by pressing its button.