Fiat 1996 Brava Service Manual page 201

Bravo-Brava ty
TD
Engine
Fuel system
10.
FUEL SYSTEM WITH LUCAS FT09 PUMP
INTRODUCTION
The devices making up the injection system are collectively responsible for introducing fuel into each
cylinder and ensuring the required quantity is provided to provide even, effective combustion.
Efficient engine operation depends largely on precise injection.
The following essential conditions must be satisfied:
- each cylinder must be provided with the amount of fuel required by the engine during each cycle as
dictated by rpm and load. In practice, this involves metering the fuel;
- the fuel must be introduced at the most effective moment and the beginning of injection must always
be repeated at the same point in the cycle. This point is chosen to bring conditions as close as possible
to the ideal engine operation cycle. It must be possible to alter this moment as the rpm changes;
- the fuel must be nebulised into tiny droplets to facilitate ignition;
- the droplets must possess sufficient kinetic energy to penetrate the mass of compressed air;
- the fuel particles must be diffused as evenly as possible in all directions so that as much of the air in the
cylinder as possible can be used for combustion
The main features of the 1910 TD indirect injection system are as follows:
- fuel injection advance managed by an electronic control unit (ECU);
- turbocharged by a turbocharger and intercooler
- cross flow intake/exhaust ducts;
- Exhaust gas recirculation system for removal of NOx (controlled by the electronic control unit);
- Crankcase case reciculation system (Blow-by).
These devices ensure that this version meets EC F2 emission requirements while also allowing better fu­
el returns, lower noise levels and better handling.
FUEL SYSTEM COMPONENTS
The fuel system is made up of the following main subsystems:
- Air intake circuit
- Fuel supply circuit
- Electric/electronic circuit
- Circuit for recirculating vapours from the crankcase (blow-by gases)
- Exhaust gas recirculation circuit (E.G.R.)
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