1995 RENAULT MEGANE SCENIC engine

INJECTION
Location of components
17
K7M engine
19EGR solenoid valve
99358-2R
18Power assisted steering pressostat
99362R
17-14

98900-1R1
INJECTION
Location of components
17
F3R engine
1Injection computer
5Fuel vapour recirculation solenoid valve
99218-1R
2Pinking sensor
(tightening torque : 2.5 daN.m)
12Coil for cylinders 1 - 4
13Coil for cylinders 2 - 3
15Anti-interference condenser
3Coolant temperature sensor (clipped)
6Cylinder reference sensor (see removal in
sub-section "Special notes for sequential in-
jection")
7Idle speed regulation solenoid valve
8Throttle position potentiometer (non-
adjustable)
9Air temperature sensor (clipped)
10Absolute pressure sensor
99238R2
4TDC sensor
99221R
17-15

INJECTION
Location of components
17
F3R engine
17Oxygen sensor
(tightening torque: 4.5 daN.m)
99224R
17-16

INJECTION
Special notes on semi-sequential injection
17
K7M engine
OPERATING PRINCIPLE
The K7M engine is fitted with semi-sequential injection.
Injection of fuel is carried out simultaneously to cylinders 1 - 4 and cylinders 2 - 3.
To do this, the two pairs of injectors are connected to two injection computer tracks:
- the injectors for cylinders 1 and 4 are connected to computer track 4 ,
- the injectors for cylinders 2 and 3 are connected to computer track 30 .
For each cylinder, there is one injection per revolution, i.e. two per cycle. These injections take place during
the compression and exhaust phases.
The injection computer uses the same system as that used to control the ignition coils for determining when
to control which injector. By analysing the signal from the flywheel, it knows the TDC point for cylinders 1 - 4
and cylinders 2 - 3 (see principle in section 17 "Ignition"). By counting the number of teeth, the engine phases
preceding TDC maybe determined.
17-17

INJECTION
Special notes on semi-sequential injection
17
K7M engine
cylinder 2compression expansion exhaust inletTDC
TDC
cylinder 3
exhaust inlet compression expansionTDC
cylinder 1
TDC TDC
inlet compression expansion exhaustTDC
cylinder 4expansion exhaust inlet compression
TDCTDCTDC
computer track
N° 4
12 V
0 V
computer track
N° 30
12 V
0 V
Ignition
1revolution 1revolution
1 cycle
injection of petrolTDC
17-18

INJECTION
Special notes on sequential injection
17
F3R engine
PRESENTATION
The F3R engine is fitted with sequential injection.
Injection of fuel is not carried out simultaneously
to all four cylinders as with conventional injection,
but cylinder after cylinder when they are at the
start of the inlet phase.
To do this, it is necessary for:
- each injector to be connected separately to
the computer (injector n° 1 is at the flywheel
end),
- the computer to know which cylinder is at the
inlet phase.
To determine the cylinder at the inlet phase, the
computer uses 2 sensors:
- the TDC sensor,
- the cylinder reference sensor.
The TDC sensor allows the computer to determine
the engine speed, and to know which cylinders
are at TDC:
- cylinders 1 and 4 at TDC,
- cylinders 2 and 3 at TDC.
The cylinder reference sensor allows the computer
to know which of the two cylinders at TDC is at
the start of the inlet phase.
DEFECT MODE IN THE CASE OF A FAULT WITH THE
CYLINDER REFERENCE SENSOR
The system remains in sequential injection. The
cycle 1 - 3 - 4 - 2 is retained.
When fuel is injected for the first time, or at the
beginning of the starting phase, the computer
decides arbitrarily to inject fuel to cylinder n° 1
when cylinders 1 and 4 are at TDC.
Two possibilities may then arise:
- the system is phased correctly,
- the system is out of phase by one revolution.
Operation of the engine is not greatly affected.
DESCRIPTION
The cylinder reference sensor (A) is located at the
end of the camshaft. It is mounted by three bolts
on to the cylinder head.
The sensor is opposite a long target of 180°. This is
mounted on the end of the camshaft.
If the target is located within the sensor air gap,
12 V is sent to the computer.
If the target is not in the sensor airgap, 0 V is sent
to the computer.
SENSOR OPERATING PRINCIPLE
The sensor is supplied with 12 Volts. The computer
sends it a 5 V feed on track 2.
Depending on the position of the target, the sen-
sor closes the circuit and earths this voltage (the
computer receives 0 V), or the sensor leaves the
circuit open (the computer receives 12 V).
99238R3
17-19

INJECTION
Special notes on sequential injection
17
F3R engine
PRINCIPLE FOR RECOGNISING THE CYLINDER AT THE INLET PHASE
Depending on the signal from the TDC sensor, the computer knows at what moment cylinders 1 and 4 are at
TDC and at what moment cylinders 2 and 3 are at TDC. (For further explanations refer to section 17
"Ignition").
Cylinders 1 and 4 are at TDC,
- if the signal from the cylinder reference sensor is 0 Volts, cylinder 4 is at the start of the inlet phase,
- if the signal from the cylinder reference sensor is 12 Volt, cylinder 1 is at the start of the inlet phase.
Cylinders 2 and 3 are at TDC,
- if the signal from the cylinder reference sensor is 0 Volts, cylinder 3 is at the start of the inlet phase,
- if the signal from the cylinder reference sensor is 12 Volt, cylinder 2 is at the start of the inlet phase.
LOGIC
Signal from cylinder
reference sensorCylinder at start of inlet phase
12 Volt 1
0 Volts 4
12 Volt 2
0 Volts 3Cylinder at TDC
1 - 4
2 - 3
17-20

INJECTION
Special notes on sequential injection
17
F3R engine
A 1 rotation of the crankshaft
B 1 rotation of the camshaft
C TDC 1 - 4
D TDC 2 - 3
1 Cylinder 1 at inlet
2 Cylinder 2 at inlet
3 Cylinder 3 at inlet
4 Cylinder 4 at inlet
5 Gap in flywheel
684° or 14 teeth
7 30 teeth
X Flywheel target
Y Camshaft target
Z Voltage from cylinder reference sensor
NOTE : All values are given in TDC degrees.
98406R1
17-21