Nissan Primera P11. Instruction — part 78
FUEL TEMPERATURE COMPENSATION
Input/output signal line
Fuel temperature sensor
E
Fuel temperature
ECM
E
Electric
governor
Crankshaft position sensor (TDC)
E
Engine speed
Control sleeve position sensor
E
Control sleeve position
The amount of fuel leaking at or around high-pressure parts inside the fuel injection pump varies with fuel
temperature and engine speed. This will result in a difference between the target amount of fuel injected and
the actual amount. The ECM compensates for the actual amount depending on the signal from the fuel
temperature sensor, the control sleeve position sensor and the crankshaft position sensor.
DECELERATION CONTROL
Input/output signal line
Accelerator sensor
E
Accelerator position
ECM
E
Electric
governor
Camshaft position sensor (PUMP)
E
Engine speed
The ECM cuts power supply delivery to the electric governor during deceleration for better fuel efficiency.
The ECM determines the time of deceleration according to signals from the accelerator sensor and cam-
shaft position sensor (PUMP).
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTION
CD20T
Fuel Injection System (Cont’d)
EC-17
Fuel Injection Timing System
SYSTEM DESCRIPTION
The fuel injection timing system determines the optimal fuel injection timing, based on engine speed, injec-
tion quantity, engine coolant temperature and atmospheric pressure. The timing is formed by a basic value
(Basic Control) and two correction values. By performing a duty cycle signal on the timing control valve, the
ECM allows the valve to provide optimal injection timing. The ECM also performs feedback control on the
timing control valve using the signal from the needle lift sensor which detects the actual fuel injection tim-
ing.
BASIC CONTROL
Input/output signal line
Crankshaft position sensor (TDC)
E
Engine speed
ECM
E
Injection
timing con-
trol valve
Needle lift sensor
E
Injection timing
Control sleeve position sensor
E
Control sleeve position
The optimal fuel injection timing data, predetermined in propor-
tion to engine speeds and amount of fuel injected, are stored in
the ECM memory. The ECM uses the data to control the fuel
injection timing.
HIGH ALTITUDE COMPENSATION
Crankshaft position sensor
E
Engine speed
ECM
E
Injection
timing
control
valve
Control sleeve position sensor
E
Control sleeve position
Atmospheric pressure sensor
E
Atmospheric pressure
Needle lift sensor
E
Injection timing
Fuel temperature sensor
E
Fuel temperature
For better drivability in high altitude areas, the fuel injection tim-
ing is advanced and the fuel quantity is reduced according to the
atmospheric pressure.
SEF650S
Fuel
injection
timing
BTDC
(degree)
Fuel injection
volume
Large
Small
Engine rpm
NEF771
Fuel
injection
timing
compensation
Normal
High altitude
Engine rpm
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTION
CD20T
EC-18
ENGINE COOLANT TEMPERATURE COMPENSATION (During driving)
Input/output signal line
Crankshaft position sensor (TDC)
E
Engine speed
ECM
E
Injection
timing con-
trol valve
Engine coolant temperature sensor
E
Engine coolant temperature
Needle lift sensor
E
Injection timing
Control sleeve position sensor
E
Control sleeve position
For better exhaust efficiency under cool engine conditions, the
fuel injection timing is controlled within a compensation range
depending on the engine speed, engine coolant temperature and
amount of fuel injected.
ENGINE COOLANT TEMPERATURE COMPENSATION (When starting)
Input/output signal line
Crankshaft position sensor (TDC)
E
Engine speed
ECM
E
Injection
timing con-
trol valve
Engine coolant temperature sensor
E
Engine coolant temperature
Needle lift sensor
E
Ignition timing
For better startability under cool engine conditions, the fuel injec-
tion timing is compensated according to the engine coolant tem-
perature.
SEF652S
Fuel
injection
timing
compensation
Engine coolant
temperature
Low
High
Engine rpm
SEF651S
Fuel
injection
timing
compensation
Engine coolant
temperature
High
Engine rpm
Low
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTION
CD20T
Fuel Injection Timing System (Cont’d)
EC-19
Air Conditioning Cut Control
INPUT/OUTPUT SIGNAL LINE
Air conditioner switch or ABS actuator
and electric unit (control unit)
E
Air conditioner “ON” signal
ECM
E
Air
conditioner
relay
Accelerator position sensor
E
Accelerator valve opening angle
Vehicle speed sensor
E
Vehicle speed
Engine coolant temperature sensor
E
Engine coolant temperature
SYSTEM DESCRIPTION
This system improves acceleration when the air conditioner is used.
When the accelerator pedal is fully depressed, the air conditioner is turned off for a few seconds.
When engine coolant temperature becomes excessively high, the air conditioner is turned off. This contin-
ues until the coolant temperature returns to normal.
Cooling Fan Control
INPUT/OUTPUT SIGNAL LINE
Vehicle speed sensor or ABS actuator
and electric unit (control unit)
E
Vehicle speed
ECM
E
Cooling fan relay(s)
Engine coolant temperature sensor
E
Engine coolant temperature
Air conditioner switch
E
Air conditioner “ON” signal
The ECM controls the cooling fan corresponding to the vehicle speed, engine coolant temperature, and air
conditioner ON signal. The control system has 3-step control [OFF/LOW/HIGH].
Operation
NEF772
Engine
coolant
temperature
°C
(°F)
Air conditioner is OFF
.
102 (216)
.
96 (205)
.
20
(12)
.
80
(50)
Vehicle speed km/h (mph)
Cooling fans do not operate
Cooling fans operate at high speed
Engine
coolant
temperature
°C
(°F)
Vehicle speed km/h (mph)
.
20
(12)
.
80
(50)
.
102 (216)
.
96 (205)
Air conditioner is ON
Cooling fans operate at low speed
ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTION
CD20T
EC-20
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