By-pass valve inside the filter support/heat exchanger assembly
This is a new generation of filters that permit much more thorough filtration as they are able to holder back a greater amount of particles of smaller dimensions than those held back by conventional filters with a paper filtering element. These high-filtration devices, to date used only in industrial processes, make it possible to:
- reduce the wear of engine components over time
- maintain the performance/specifications of the oil and thereby lengthen the time intervals between changes.
Iveco CURSOR EURO 4 ENGINES Service Manual
The filtering elements are closely wound by a spiral so that each fold is firmly anchored to the spiral with respect to the others. This produces a uniform use of the element even in the worst conditions such as cold starting with fluids with a high viscosity and peaks of flow. In addition, it ensures uniform distribution of the flow over the entire length of the filtering element, with consequent optimization of the loss of load and of its working life.
Mount upstream
To optimize flow distribution and the rigidity of the filtering element, this has an exclusive mount composed of a strong mesh made of nylon and an extremely strong synthetic material.
Filtering element
Composed of inert inorganic fibres bound with an exclusive resin to a structure with graded holes, the element is manufactured exclusively to precise procedures and strict quality control.
Mount downstream
A mount for the filtering element and a strong nylon mesh make it even stronger, which is especially helpful during cold starts and long periods of use. The performance of the filter remains constant and reliable throughout its working life and from one element to another, irrespective of the changes in working conditions.
Structural parts
The o-rings equipping the filtering element ensure a perfect seal between it and the container, eliminating by-pass risks and keeping filter performance constant. Strong corrosion-proof bottoms and a sturdy internal metal core complete the structure of the filtering element.
VGT TURBOCHARGER
Operating principle: The variable geometry turbocharger (VGT) consists of a centrifugal compressor and a turbine, equipped with a mobile device which adjusts the speed by changing the area of the passing section of exhaust gases to the turbine. Thanks to this solution, gas velocity and turbine speed can be high even when the engine is idling. If the gas is made to go through a narrow passage, in fact, it flows faster, so that the turbine rotates more quickly.
The movement of the device, choking the exhaust gas flowing section, is carried out by a mechanism, activated by a pneumatic actuator. This actuator is directly controlled by the electronic control unit by a proportional solenoid valve. The device is in maximum closing condition at idle speed. At high engine operating speed, the electronic control system is activated and increases the passing section, in order to allow the in-coming gases to flow without increasing their speed. A toroidal chamber is obtained during the casting process in the central body for the passage of the coolant.
Working principle (See Figure 19) The actuator piston, connected to the drive rod, is controlled with the compressed air introduced through the air inlet (1) on the top of the actuator.
Modulating the air pressure varies the movement of the piston and turbine control rod. As the piston moves, it progressively compresses the external spring (4) until the base of the piston reaches the disc (5) controlling the internal spring (6). On further increasing the pressure, the piston, via the disc (5), interferes with the bottom limit stop (10). Using two springs makes it possible to vary the ratio between the piston stroke and the pressure. Approximately 85% of the stroke of the rod is opposed by the external spring and 15% by the internal one.
Solenoid valve for VGT control
This N.C. proportional solenoid valve is located on the left-hand side of the crankcase under the turbine. The electronic control unit, via a PWM signal, controls the solenoid valve, governing the supply pressure of the turbine actuator, which, on changing its position, modifies the cross-section of the flow of exhaust gases onto the blades of the impeller and therefore its speed. The resistance of the coil is approx. 20-30 Ohms.
DeNOx SYSTEM 2
General remarks
In order to keep the exhaust emission values of nitric oxides (NOx) within the limits prescribed by the Euro 4 standard, with low fuel consumption, a system for post-processing of the above substances found in exhaust gas has been fitted to the vehicles. This system essentially consists of an electronic-control oxidizing catalyst. The system converts, through the SCR (Selective Catalytic Reduction) process, nitric oxides (NOx) into inert compounds: free nitrogen (N2) and water vapour (H2O). The SCR process is based on a series of chemical reactions, which leads, due to ammonia reacting with exhaust gas oxygen, to a reduction of nitric oxides (NOx) found in exhaust gas.
FUNCTIONAL WIRING DIAGRAM
The AdBlue fluid level gauge control consists of a device made up of a set of resistors, a float, a NTC temperature sensor, and a coil used to heat the fluid under low temperature conditions. It informs the control unit of any current change due to the resistor determined by the float position with respect to the AdBlue fluid level.
Nozzle
Garages are authorized to perform fault diagnosis solely on the entire injection system and may not work inside the injector-pump, which must only be replaced. A specific fault-diagnosis program, included in the control unit, is able to check the operation of each injector (it deactivates one at a time and checks the delivery of the other five).
Fault diagnosis makes it possible to distinguish errors of an electrical origin from ones of a mechanical/hydraulic origin. It indicates broken pump-injectors. It is therefore necessary to interpret all the control unit error messages correctly. Any defects in the injectors are to be resolved by replacing them.