gas type RENAULT SCENIC 2000 J64 / 1.G Technical Note 3426A Workshop Manual

Downloaded from www.Manualslib.com manuals search engine DIESEL EQUIPMENT
Special notes
13
13-4
OPERATION
The common rail direct high pressure injection system is a sequential diesel injection system (based on the
operation of multipoint injection for petrol engines).
This new injection system reduces operating noise, lowers the quantity of polluting gas and particles and produces
significant engine torque at low engine speeds thanks to a pre-injection procedure.
The low pressure pump (also called the supercharging pump) supplies the HP pump, through the filter with pressure
of between 2.5 and 4 bars.
The HP pump generates the high pressure sent to the injection rail. The pressure regulator located on the pump
modulates the value of the high pressure via the computer. The rail supplies each injector through a steel pipe.
The computer:
– determines the value of injection pressure necessary for the engine to operate well and then controls the pressure
regulator. It checks that the pressure value is correct by analysing the value transmitted by the pressure sensor
located on the rail,
– determines the injection time necessary to deliver the right quantity of diesel and the moment when injection should
be started,
– controls each injector electrically and individually after determining these two values.
The injected flow to the engine is determined depending on:
– the duration of injector control,
– the injector opening and closing speed,
– the needle stroke (determined by the type of injector),
– the nominal injector hydraulic flow (determined by the type of injector),
– the high pressure rail pressure controlled by the computer.
FOR ANY INTERVENTION IN THE HIGH PRESSURE INJECTION SYSTEM YOU MUST RESPECT THE
CLEANING AND SAFETY ADVICE SPECIFIED IN THIS DOCUMENT.