Bosch Unit Pump System (UPS)
The principle of the UPS unit-pump system is the same as that of the UIS unit injector. It is a modular high-pressure injection system. Similar to the UIS, the UPS system features one UPS single plunger injection pump for each engine cylinder. Each UP pump is driven by the engine’s camshaft. Connection to the nozzle-and-holder assembly is through a short high-pressure delivery line precisely matched to the pump-system components.
Electronic map-based control of the start of injection and injection duration (in other words, of injected fuel quantity) leads to a pronounced reduction in the diesel engine’s toxic emissions. The use of a high-speed electronically triggered solenoid valve enables the characteristic of the individual injection process, the so-called rate-of-discharge curve, to be precisely defined.