The direct Diesel engine injection system should lower the fuel consumption, and reduce emissions, by simultaneously increasing power and torque especially for low numbers of revolution.
Pure air is sucked in. With a mechanical high-pressure pump, powered by the engine, the fuel is injected with 250 to 2000 bar into the highly compressed air. The particle emission decreases with rising pressure. The fuel is injected directly to the wall of an upwards open hollow cavity in the piston. The immediate combustion is toned down somewhat, because the fuel burns down in layers. This reduces the hard running of the engine. Due to the lower heat dissipation, a pre-heating system is not necessary, or only when it is cold (-5°C). The side combustion chamber system does make use of a pre-heating system. For the direct injection system in the petrol engine with approx. 100 bar injection pressure, the ignition system determines the ignition time. The harder engine run is reduced by a little lower compression. The raised nitrogen oxides are compensated by exhaust gas recirculation or the DeNOx-catalyst. Especially the diesel engine, but also the petrol-driven car, display more torque and a higher achievement. The additional advantage for the diesel engine is that this higher torque is achieved at low engine speeds. The maximum engine speed is limited though.