oil viscosity RENAULT SCENIC 2011 J95 / 3.G Engine And Peripherals EDC16C36 Workshop Manual

13B-20V9 MR-372-J84-13B450$050.mif
DIESEL INJECTION
Fault finding – Features13B
EDC16 C36
Program No.: 91
Vdiag No.: 44, 4C, 48,
50, 54, 58
Exhaust gas recirculation management:
The EGR (Exhaust Gas Recirculation) system involves removing exhaust gases and reintroducing them into the
inlet.
The exhaust gases are collected in the exhaust manifold (before the turbocharger), then directed to the EGR cooler
and the EGR valve.
EGR cooler
The EGR cooler bypass function cools the gases extracted from the exhaust via a gas-water exchanger and then
reintroduces the gases at the inlet. This cooler is equipped with an all-or-nothing solenoid valve, which enables
gases to be cooled or not cooled, depending on the emission control requirements.
EGR valve
The system comprises a direct current EGR valve and a potentiometer which reports the position of the valve.
A positive command controls its opening (0 → 100%).
The potentiometer serves to control and run fault finding on the valve.
The very first time the engine is started, then each subsequent engine start, the “valve closed” position is
programmed (offset). This value is compared to the very first offset or last programmed offset, for the purposes of
fault finding. It is also used to readjust the valve control function. This is why it is important to associate the EGR
valve to the computer which controls it.
Richness ratio sensor management (only on certain F9Q816 engines in VDiag 48):
The richness ratio sensor is mounted in the turbo outlet.
Its function is to reset the injection system drift.
The injection computer does not control the sensor immediately when the engine has just been started:
–ET300 Richness regulation is INACTIVE,
–PR779 Richness ratio sensor is equal to 1.
After a length of time that depends on the coolant temperature, with the engine running and in the absence of no
load conditions, the injection computer authorises the heating of the sensor:
–ET300 Richness regulation changes to ACTIVE,
– in about ten seconds, the PR778 Richness ratio sensor temperature increases to approximately 780°C,
– then the PR779 Richness ratio sensor displays a value of 0.3 ±0.1 at idle speed.
The turbocharger cooling pump:
Because of its high rotation speed, the turbocharger does not use ball bearings to ensure the pivot connection but
uses a bearing whose friction is reduced thanks to a pressurised film of oil.
When the engine is switched off, the oil is no longer under pressure and no longer provides the pivot connection. A
quantity of oil therefore remains, which collects around the bearing.
When the turbocharger is in operation, the bearing is subjected to high temperatures. After the engine is switched
off, the slow decrease in temperature heats the stagnant oil. This then modifies the viscosity of the oil and therefore
increases the risk of the turbocharger sticking.
To prevent this, a turbocharger coolant pump circulates coolant to lower the temperature of the turbocharger. It is
electrically activated for 5 mins if the engine coolant temperature exceeds 80°C. In addition, the coolant circulation
prevents deterioration of the liquid properties by stopping it collecting under the same temperature constraints as the
oil.