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.