2888243 - 1060G pressure pump electric control
The main characteristics of the Unijet system are:
- high injection pressure (up to 1350 bar);
- possibility of modulating the injection pressure under all engine working conditions between 150 and 1500 bar;
- introduction of fuel up to 100 mm3/cycle in a range between 100 and 6000 rpm .
- precise injection control, for both injection advance and duration of injection;
- pilot injection, before top dead centre, managed in relation to the engine rpm and load which allows the pressure derivative in the combustion chamber to be reduced, with a reduction in the noise level.
TECHNICAL ADVANTAGES
The advantages of the Unijet system are:
- it improves the formation of the air-fuel mixture;
- the injection pressure may be freely selected from within wide limits;
- the start of fuel injection and the amount of diesel injection can also be freely determined;
- it is more flexible when operating conditions vary, especially under cold conditions;
- ecological and economic combustion.
- requires less engine power for its operation;
- simplified system;
- modular system;
- better performance at lower cost.
The results obtained with the Unijet system are:
- increased torque and power delivered by the engine;
- reduction in fuel consumption;
- reduction in pollutant emissions;
- reduction in total engine noise;
- improvement in the driveability of the vehicle.
OPERATION
The main functions of the system are basically as follows:
- control of the fuel temperature
- control of the engine coolant temperature
- control of the quantity of fuel injected
- control of the idle speed
- fuel cut-off during overrunning
- control of the cylinder balance during idling
- control of irregular operation
- control of exhaust fumes during acceleration
- control of exhaust gas recirculation (E.G.R.)
- control of maximum torque restriction
- control of maximum speed restriction
- control of the heater plugs
- control of engagement of climate control system (where fitted)
- control of auxiliary fuel pump
- control of the position of the cylinders
- control of the main injection advance and operation
- control of the closed loop injection pressure
- control of the electrical balance
- control of the turbocharging pressure
- self diagnosis
- connection with the Fiat CODE control unit (Immobilizer)
INJECTION SYSTEM
The Common Rail system makes it possible to carry out a pre-injection before T.D.C. with the advantage of reducing the derivative of the pressure in the combustion chamber, reducing the value of the combustion noise, typical of direct injection engines. The control unit controls the quantity of fuel injected, regulating the line pressure and injection times.The control unit processes the following information to control the quantity of fuel to inject:
- engine rpm
- coolant temperature
- turbocharging pressure
- air temperature
- intake air quantity
- battery voltage
- diesel pressure
- accelerator pedal position.
DIAGRAM OF INPUT/OUTPUT INFORMATION TO/FROM THE CONTROL UNIT
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SYSTEM OPERATING LOGIC
Self-diagnosis
The control unit's self-test system checks the signals coming from the sensors, comparing them with the permitted limits:
- indication of faults upon start-up
- warning light on for 4 s indicates test stage
- warning light off after 4 secs indicates no faults in components that could affect the values established in emission control regulations
- warning light on after 4 s indicates fault.
- fault indication during operation
- warning light on indicates fault
- warning light off indicates no faults in components that could affect the values established by emission control regulations
- recovery
- the control unit defines as and when required the type of recovery depending on the faulty components
- the recovery parameters are managed by non-faulty components.
Recognition of fiat code
When the control unit receives the ignition 'ON' signal, it dialogues with the Fiat CODE control unit to obtain starting enablement.
Control of the fuel temperature
When the temperature of the fuel is 110°C, measured by the sensor at the recirculation manifold, the control unit operates the pressure regulator to reduce the line pressure (it does not modify the injection times).
Control of the engine coolant temperature
With the temperature of the engine coolant greater than 105°C, the control unit:
- reduces the quantity of fuel injected (reduces the engine power)
- operates the cooling fans
- lights up the coolant overheating warning light.
Control of the quantity of fuel injected
On the basis of the signals coming from the sensors and the values in the map, the control unit:
- operates the pressure regulator
- varies the injection time up to 3000 rpm
- varies the 'main' injection time.
Control of the idle speed
The control unit processes the signals coming from the various sensors and regulates the quantity of fuel injected:
- operates the pressure regulator
- varies the injector injection times.
Fuel cut-off during overrunning
When the accelerator pedal is released the following logics are implemented:
- cuts off the supply to the fuel injectors
- it partially reactivates the supply to the injectors before the idle speed is reached
- operates the fuel pressure regulator.
Control of the cylinder balance during idling
On the basis of the signals received from the sensors, the control unit controls the precision of the torque at idle speed:
- varies the quantity of fuel injected in the individual injectors (injection time).
Control of irregular operation
The control unit processes the signals received from the various sensors and determines the quantity of fuel to be injected via:
- the pressure regulator
- the opening time of the injectors.
Control of exhaust fumes during acceleration
When there is considerable acceleration, the control unit determines the optimum quantity of fuel to be injected, on the basis of the signals received from the flow meter and engine rpm sensor:
- operates the pressure regulator
- varies the injector injection time.
Control of exhaust gas recirculation (e.g.r.)
On the basis of the engine load and signal coming from the accelerator pedal potentiometer, the control unit restricts the amount of air drawn in, implementing the partial intake of exhaust gases.
Eobd (european on board diagnosis) system
The implementation of the EOBD function is managed by the engine management control unit which manages the yellow warning light for the engine management system (EOBD) as described below.The warning light: is activated on request by the engine control unit for about 4 seconds (check) when the ignition key is turned to 'MAR'.The EOBD system carries out continuous diagnosis of the car's petrol fuel system components relating to emissions and indicates any deterioration of these components by the warning light in the instrument panel coming on.The aim of the system is:
- keeping the efficiency of the system under control;
- signalling an increase in emissions due to a vehicle malfunction;
- signalling the need to replace deteriorated components.
 | Prompt repair of the problem which has caused the warning light to come on is vital in accordance with the legal requirements of the traffic regulations of the country in question. |
Control of maximum torque limitation
According to the number of revs, the control unit calculates the following from predefined maps:
- the torque limit
- the permissible fumes (limit).
It compares these minimum values and corrects them with other parameters:
- coolant temperature
- engine rpm
- vehicle speed
Control of maximum speed limit
According to the number of revs, the control unit implements two intervention strategies:
- at 5000 rpm it cuts off the fuel, reducing the line pressure
- above 5400 rpm it deactivates the auxiliary pump and the injectors.
Control of heater plugs
The control unit, during the following stages:
- starting
- post-starting
Control of air conditioning system activation
The control unit operates the air conditioning compressor:
- switching it on/off when the relevant switch is pressed
- switching it off momentarily (for around 6 secs) if there is substantial acceleration or a request for maximum power.
Control of auxiliary electric fuel pump
Irrespective of the engine speed, the control unit:
- supplies the auxiliary fuel pump with the ignition key in the ON position
- excludes the auxiliary pump supply if the engine is not started up within a few seconds.
Control of cylinder position
During each revolution of the engine, the control unit recognizes which cylinder is in the explosion stroke and operates the injection sequence at the appropriate cylinder.
Control of main and operated injection advance
On the basis of the signals coming from the various sensors, including the absolute pressure sensor in the actual control unit, the control unit determines the optimum injection point according to an internal map.
Control of closed loop injection pressure
On the basis of the engine load, determined by processing the signals coming from the various sensors, the control unit operates the regulator to obtain optimum line pressure.
Control of electrical balance
According to the battery voltage, the control unit varies the idle speed:
- increases the injector injection time
- regulates the line pressure.
Control of turbocharging pressure
At the various engine operating speeds, the control unit processes the signal coming from the turbocharging sensor and determines the quantity of fuel to be injected:
- operates the pressure regulator
- varies the injection time.
Recovery
The faulty components are shown in bold whilst the operation of the control unit is described in light type Engine rpm sensor: Interruption in the fuel supplyEngine timing sensor: Engine starting not possibleFuel pressure sensor: Operation in open-loop limiting fuel pressure - a pressure value of 0 bar is assumedSupercharging pressure sensor: Interruption of supercharging operation A pressure of 0.9 bar is assumedFlow meter: EGR operation disabledTemperature sensor: With the engine running a flu| ... DATA ERROR - CROPPED TEXT | Ошибка данных - Текст обрезан ... |
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