High-pressure fuel system: Notes

The 4-cylinder gasoline engine operates with direct fuel injection. The purpose of direct fuel injection is to increase performance. The maximum fuel pressure in this case is 120 bar (idle: 50 bar, full load: 120 bar). The use of direct fuel injection creates a homogeneous mixture preparation in the entire combustion chamber.

Homogeneous mixture preparation means that the fuel-air ratio is regulated stoichiometrically in the same way as for intake pipe fuel injection (Lambda = 1). "Stoichiometrically" means a ratio of 14.7 kilograms of air to 1 kilogram of fuel. Due to the homogeneous mixture preparation, conventional exhaust re-treatment can be used.

Fig 1: Identifying High-Pressure Fuel System Components

Courtesy of BMW OF NORTH AMERICA, INC.