Fuel System
- Connector.
- Fuel rail
- Sensor, fuel pressure high pressure circuit
- High pressure line
- High pressure pump
- Fuel pump
- Fuel pump module
- Low pressure line
- Sensor, fuel pressure low pressure circuit
- Injector
Overview
The main components of the fuel system are:
- High pressure pump with control valve, fuel flow
- Fuel rail
- Sensor, fuel pressure high pressure circuit
- Injector
- Sensor, fuel pressure low pressure circuit
- Fuel pump, low pressure
The fuel pressure in the fuel rail is approx. 11 MPa (110 bar) at idle and varies at other loads between 2 MPa to 20 MPa (200 bar).
To accurately control injection at idle, relatively high pressure is required. This is to obtain a correct predetermined injection amount at short injection times under 1 ms.
If the fuel pressure in the fuel rail exceeds 23 MPa (230 bar), a safety valve opens in the high pressure pump and the fuel is routed to the inlet side (low pressure side).
In general, the greater the load the higher the fuel pressure. The principle of regulation is based on a calculation model in the engine control module (ECM). Based on the driver's torque request, the following occurs: Air request → measured quantity of air → desired fuel quantity → desired fuel pressure → measured fuel pressure → gives desired fuel quantity through injection timing.