SHOP MANUAL
Ch 6 page 66
ELECTRICAL SYSTEM
Introduction
The S8 has been developed to control the Scania XPI fuel system. More components than before are controlled
by the engine control unit and the control of some components has been extended.
The communication and control of the following components operates as in the S7:
Engine speed sensors
Coolant temperature sensor
Charge air pressure sensor
Charge air temperature sensor
Oil pressure sensor
Fuel temperature sensor
Starter motor
Control of fuel injection
Control of alternator
Oil level sensor
Solenoid valve for the AC compressor
Fan
Exhaust brake proportional valve
General
The engine management system controls the fuel system, SCR system, variable geometry turbocharger and a
number of other components such as the alternator, starter motor, and AC compressor
Electronic control of the fuel system provides increased control over injection, allowing combustion to be opti-
mised. Optimum combustion results in turn in lower fuel consumption.
Electronic control of the fuel system is required to meet emission requirements.
A brief description of the way in which the engine management system and the components concerned work
together follows. A more detailed description of the components and their interaction with the engine manage-
ment system is provided under the relevant component.
Fuel injection
The engine control unit receives a message via CAN if acceleration is requested. The engine control unit re-
ceives information about the engine speed, fuel temperature and fuel pressure, charge air pressure and charge
air temperature from the relevant sensors. The engine control unit then controls the components in the fuel
system so that the correct amount of fuel is injected. The engine control unit also takes into account information
about the turbocharger speed, air temperature and air flow to the engine in order to supply fuel to the injectors.
To Next Page
Loading...