184000278 - 1060G PRESSURE PUMP ELECTRIC CONTROL
CONSTRUCTION FEATURES
The main characteristics of the Unijet system are:
- high injection pressure (up to 1400 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 condidtions;
- ecological and economical 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;
- lower fuel consumption;
- reduction in pollutant emissions
- reduced total engine noise;
- improved car handling.
Operation
The main functions of the system are basically as follows:
- control of fuel temperature;
- control of engine coolant temperature;
- control of quantity of fuel injected;
- control of the idle speed;
- fuel cut-off during overrunning;
- control of 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 limiting;
- control of maximum speed limiting;
- control of heater plugs;
- control of entry into operation of climate control system (where fitted);
- control of auxiliary fuel pump;
- control of cylinder position;
- control of main and pilot injection advance;
- control of closed loop injection pressure;
- control of electrical balance;
- control of turbocharging pressure;
- autodiagnosis;
- connection with the Fiat CODE control unit (Immobilizer).
Fuel injection system
The Common Rail systems 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 info to/from control unit
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System operating modes
Self-diagnosis
The control unit's self-test checks the signals coming from the sensors, comparing them with the permitted limits:Indication of faults upon start-up:
- warning light for 4 s indicates test stage;
- warning light off after 4 s 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 in emission control regulations
Recovery:
- from time to time, the control unit defines the type of recovery according to the components which are faulty;
- the recovery parameters are managed by non-faulty components.
Recognition of fiat code
When the control unit receives the ignition 'ON' signal, it communicates with the body computer to obtain starting enablement.
Control of the fuel temperature
With the temperature of the fuel 110°C, measured by the sensor on the fuel filter casing cover, the control unit operates the pressure regulator in order 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.
Intake valve control
The control unit supplies the valve control solenoid when the engine is turned off. This causes closure of the throttle valve on the intake duct and cuts of the flow of air to the cylinders.
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 'pilot' 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:
- it operates the pressure regulator;
- it varies the injector injection time.
Fuel cut-off during overrunning
When the accelerator pedal is released the following logics are implemented:
- it cuts off the supply to the fuel injectors;
- it partially reactivates the supply to the injectors before the idle speed is reached;
- it 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:
- it 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 the 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:
- it operates the pressure regulator;
- it varies the injector injection time.
Control of the 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:
- to monitor the efficiency of the system;
- to signal an increase in emissions due to a vehicle malfunction;
- to signal 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 the maximum torque restriction
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 the 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 the heater plugs
The control unit, during the following stages:
- starting;
- post-starting;
Control of entry into operation of the air conditioning system
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 s) if there is substantial acceleration or a request for maximum power.
Control of the 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 the position of the cylinders
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 the 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 the electrical balance
According to the battery voltage, the control unit varies the idle speed:
- it increases the injector injection time;
- it regulates the line pressure.
Control of the turbocharging pressure
At the various
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| Pin | Name | Signal type |
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| 3 | Fuel system | 12V |
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WATER IN FUEL SENSOR
Incorporated in the fuel filter container casing, at the bottom, it indicates the presence of water via the warning light on the instrument panel.