Mitsubishi Outlander XL. Manual — part 1246
(injection time). There is a prescribed basic drive time
that varies according to the engine speed and intake
air volume. ECM adds prescribed compensations to
this basic drive time according to conditions such as
the intake air temperature and engine coolant
temperature to decide injection time. Fuel injection is
done separately for each cylinder and is done once in
two engine rotations.
System Configuration Diagram
ZK602750
ECM
Injector
Mass airflow sensor
Manifold sbsolute pressure
sensor
Intake air temperature sensor
Engine coolant temperature
sensor
Throttle position sensor
Crankshaft position sensor
Camshaft position sensor
Knock sensor
Ignition switch-ST
Heated oxygen sensor
AA00
1. INJECTOR ACTUATION (FUEL INJECTION)
TIMING
Injector drive time in case of multiport fuel injection (MFI) is
controlled as follows according to driving conditions.
13A-32
MULTIPORT FUEL SYSTEM (MFI)
FUEL INJECTION CONTROL
Fuel Injection During Cranking and Normal Operation
ZK600287
<No.6TDC>
<No.6TDC>
<No.1TDC>
<No.2TDC>
<No.3TDC>
<No.4TDC>
<No.5TDC>
Camshaft position
sensor signal
H
L
H
L
Cylinder Stroke
No.1 cylinder
No.2 cylinder
No.3 cylinder
No.4 cylinder
No.5 cylinder
No.6 cylinder
Intake
Intake
Intake
Intake
Intake
Intake
Fuel injection
Fuel injection Fuel injection
Fuel injection
Fuel injection
Fuel injection
Compression
Compression
Compression
Compression
Compression
Compression
Combustion
Combustion
Combustion
Combustion
Combustion
Combustion
Exhaust
Exhaust
Exhaust
Exhaust
Exhaust
Exhaust
Exhaust
AA01
Crankshaft position
sensor signal
Fuel injection to each cylinder is done by driving the injector at
optimum timing while it is in exhaust process based on the
crankshaft position sensor signal. ECM compares the crankshaft
position sensor output pulse signal and camshaft position sensor
output pulse signal to identify the cylinder. Using this as a base,
it performs sequential injection in the sequence of cylinders 1,
2, 3, 4, 5, 6.
Additional Fuel Injection During Acceleration
ZK600288
<No.6TDC>
<No.6TDC>
<No.1TDC>
<No.2TDC>
<No.3TDC>
<No.4TDC>
<No.5TDC>
H
L
Cylinder Stroke
No.1 cylinder
No.2 cylinder
No.3 cylinder
No.4 cylinder
No.5 cylinder
No.6 cylinder
Intake
Intake
Intake
Intake
Intake
Intake
Compression
Compression
Compression
Compression
Compression
Compression
Combustion
Combustion
Combustion
Combustion
Combustion
Combustion
Exhaust
Exhaust
Exhaust
Exhaust
Exhaust
Exhaust
Exhaust
AA01
Increase injection for acceleration
Crankshaft position
sensor signal
In addition to the synchronizing fuel injection with crankshaft
position sensor signal during acceleration, the volume of fuel is
injected according to the extent of the acceleration.
MULTIPORT FUEL SYSTEM (MFI)
13A-33
FUEL INJECTION CONTROL
2. Fuel injection volume (injector drive time)
control
The figure shows the flow for injector drive time calculation.
Basic drive time is decided based on the airflow sensor signal
(intake air volume signal) and crankshaft position sensor signal
(engine rotation signal). This basic drive time is compensated
according to signals from various sensors and optimum injector
drive time (fuel injection volume) is calculated according to
driving conditions.
Fuel Injection Volume Control Block Diagram
ZK600289
Mass airflow sensor
Crankshaft
position sensor
Heated oxygen
sensor
Engine coolant
temperature
compensation
Engine coolant
temperature sensor
Manifold absolute
pressure sensor
Fuel pressure
compensation
Barometric pressure
sensor
Battery voltage
compensation
Battery voltage
Basic fuel
injection time
determination
Air fuel ratio
compensation
(Predetermined
compensation)
Heated oxygen
sensor feedback
compensation
Injector
Acceleration-
deceleration
compensation
AA00
13A-34
MULTIPORT FUEL SYSTEM (MFI)
FUEL INJECTION CONTROL
[Injector basic drive time]
Fuel injection is performed once per cycle for each cylinder.
Basic drive time refers to fuel injection volume (injector drive
time) to achieve theoretical air-fuel ratio for the intake air volume
of 1 cycle of 1 cylinder. Fuel injection volume changes according
to the pressure difference (injected fuel pressure) between
manifold pressure and fuel pressure (constant). So, injected fuel
pressure compensation is made to injector drive time for
theoretical air-fuel ratio to arrive at basic drive time.
ZK600290AA00
Basic fuel
injection time
Fuel injection pressure compensation
Intake air amount per cycle per cylinder
Theoretical air-fuel ratio
Intake air volume of each cycle of 1 cylinder is calculated by ECM
based on the airflow sensor signal and crankshaft position
sensor signal. Also, during engine start, the map value
prescribed by the coolant temperature sensor signal is used as
basic drive time.
[Injector drive time compensation]
After calculating the injector basic drive time, the ECM makes
the following compensations to control the optimum fuel injection
volume according to driving conditions.
List of main compensations for fuel injection control
Compensations
Content
Heated oxygen sensor feedback compensation
The heated oxygen sensor signal is used for making
the compensation to get air-fuel ratio with best
cleaning efficiency of the 3-way catalytic converter.
This compensation might not be made sometimes
in order to improve drivability, depending on driving
conditions. (Air-fuel ratio compensation is made.)
Air-fuel ratio compensation
Under driving conditions where heated oxygen
sensor feedback compensation is not performed,
compensation is made based on pre-set map values
that vary according to engine speed and intake air
volume.
Engine coolant temperature compensation
Compensation is made according to the engine
coolant temperature. The lower the engine coolant
temperature, the greater the fuel injection volume.
Acceleration/ Deceleration compensation
Compensation is made according to change in
intake air volume. During acceleration, fuel injection
volume is increased. Also, during deceleration, fuel
injection volume is decreased.
MULTIPORT FUEL SYSTEM (MFI)
13A-35
FUEL INJECTION CONTROL
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