3308492 - 1060G pressure pump electric control
VIEW OF ASSEMBLY
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OPERATION OF THE INJECTION SYSTEM
The EDC-15C Common Rail is a high pressure electronic injection system for direct injection fast diesel engines.The main features are:
- availability of high injection pressures (1350 bar)
- possibility of modulating these pressures between 150 bar and a maximum operating pressure of 1350 bar, irrespective of the engine rotation speed and load
- capacity of operating at high engine speeds (up to 6000 rpm)
- precision injection (advance and duration)
- reduction in consumption
- reduction in emissions.
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 supercharging pressure
- self-test
- connection to Alfa Romeo CODE (Immobilizer) control unit
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 speed
- coolant temperature
- supercharging pressure
- air temperature
- intake air quantity
- battery voltage
- diesel pressure
- accelerator pedal position.
OPERATION
Diagram showing information entering/leaving the control unit
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SYSTEM OPERATING LOGICS
Autodiagnosis
The control unit's self-test checks the signals coming from the sensors, comparing them with the permitted limits:indication of starting faults
- warning light on for 4 secs 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 secs 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:
- 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 the alfa romeo code
When the control unit receives the ignition "ON" signal, it dialogues with the Alfa Romeo CODE control unit to obtain starting enablement.
Control of the fuel temperature
With the temperature of the fuel 110° C, measured by the sensor at the recirculation manifold, 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 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
- 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 speeds:
- 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:
- operates the pressure regulator
- 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.
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 the engagement 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 secs) 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 several 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:
- increases the injector injection time
- regulates the line pressure.
Control of the supercharging pressure
At the various engine operating speeds, the control unit processes the signal coming from the supercharging sensor and determines the quantity of fuel to be injected:
- operates the pressure regulator
- varies the injection time.
Control of the cruise control system (where fitted)
According to the position of the cruise control lever, the control unit directly controls the quantity of fuel injected to control and maintain the vehicle speed memorized.A warning light in the dashboard, activated by the control unit, indicates whether the system is operating or not.The cruise control is momentarily disabled:
- operating the brake,
- operating the clutch;
EDC-15C COMMON RAIL INJECTION CONTROL UNIT
It is fitted in the passenger compartment on the passenger side panel. The control unit is the "flash EPROM" type, i.e. it is reprogrammable from the outside without intervening on the hardware.The injection control unit integrates the absolute pressure sensor.Pin-out
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