Introduction
In diesel
engines of the VAG group, in the 1.6 CAYC version , this electronic management
system for injection of fuel is carried out using a Simos PCR 2.1
Continental Common Rail System. The high pressure pump is driven by the
timing chain and the injectors are the piezoelectric type. The engine control
unit controls and regulates the fuel pressure and dose. In this chapter we will
discuss the high-pressure pump.
High pressure
fuel pump
This is fixed on the front right hand side of the
engine and is driven by the timing belt. It is a two piston pump that works
with maximum pressures of 1600 bar.
It incorporates a mechanical pump attached and
driven by the same shaft; this pump increases the pressure coming from the fuel
electric pump at an internal pressure of 5 bar, thereby supplying the high
pressure pistons for the different loading and operating conditions of the
system.
Fuel flow regulator solenoid valve
It is fastened to the high pressure pump and
regulates the flow of fuel in the high pressure pistons, compressing only the
fuel required according to the calculations of the management unit. It works
together with the injection rail fuel pressure regulating valve in order to
maintain the ideal flow and pressure at each engine load condition.
The solenoid control valve is supplied with 12 V
from the battery and a PWM signal manages the control unit. With the engine
idling, the duty cycle is lower.
As the engine load is accelerated or increased, the Duty Cycle is greater, increasing the flow of compressed fuel through the pump. It should be taken into account that on increasing the rpm the quantity of fuel compressed also increases.
