The Scania HPI (high pressure injection) system minimises harmful emissions without imposing unnecessary restrictions on fast build-up of torque. It is a system that is also highly fuel efficient as a result of infinitely variable minute adjustments in timing that ensure the delivery of fuel is always very precise.

Back to basic mechanics
The Scania HPI unit injector is in many respects similar to traditional mechanical injectors that have been used for many years. Fuel is pressed into the combustion chamber at high pressure by a mechanical plunger, driven by the engine’s camshaft. The innovation in the injector is Time Pressure Metering. The technique uses a separate feed of fuel to the injector to adjust timing.

By making infinitely small variations in the volume of injection and timing fuel introduced into the injector, it is possible to have precise control of the injection and thus how it affects consumption and emissions.

More than an economic argument
In addition to the significant benefits of high torque, good economy and low emissions, Scania HPI has other worthwhile benefits: easy, low cost maintenance, lower noise levels and warm fuel.