Direct high pressure injection
Direct high-pressure injection is better known as one of the many designations that manufacturers give such as GDI, PDI, DPI, SIDI or FSI. The direct injection ensures that the fuel is injected under high pressure via a fuel rail into the combustion chamber of each cylinder, controlled by a fuel pressure sensor and a dosing valve.
The advantages of this management system is that the injection pressure can be regulated, the fuel is better distributed. During the injection the fuel is atomized and this has a cooling effect for the combustion chamber and higher compression ratios. The higher compression translates to more power, increased ignition efficiency and more power when repacking the engine.
The rail is susceptible to poor fuel, outdated fuel filter and incorrect use of additives. There can also build up carbon monoxide on the valves. Defects in the direct injection system can be very costly, so have your system checked regularly.
Injectors ensure that fuel from the fuel rail is injected into the combustion chamber. New injectors ensure better homogenous combustion and can handle higher pressures. These are quieter than older type injectors and have a better reactivity when opening and closing. The new types spray the fuel better into the cylinder in such a way that no fuel mixture precipitates against the cylinder wall.
However, these injectors are sensitive and can fail if poor fuel, incorrect additive use or an outdated fuel filter is used.