Duse Pump Injection System


Duse Pump Injector
1. Injection nozzle
2. Nozzle needle
3. Nozzle spring
4. High-pressure chamber
5. Pump plunger
6. Pump body
7. Return spring
8. Control attachment for camshaft rocker arm
9. Solenoid valve
10. Valve seat
11. Fuel feed line
12. Fuel return duct if solenoid valve in resting position (return valve open)
13. Fuel injection duct if solenoid valve with switch impulse (return valve closed)


Unit injector system UIS

The unit injector system is also known by its abbreviation UIS. Unit injector systems are seated in the individual cylinders. They are driven by the engine camshaft via an additional injection cam. The individual pump element and injection nozzle are grouped in one unit. Each UIS is equipped with a quick-action solenoid valve. An electronic control unit with characteristic map control (EDC) activates this valve and thus determines the start of injection and duration of injection. The great advantage of the UIS is that all high-pressure lines are eliminated. Nowadays, pressures of up to 1800 bar can be generated in the unit located directly in the cylinder head; in future, over 2000 bar will be possible. There are significantly higher injection pressures on the HPI system (High Pressure Injection) from Scania. Here, separately arranged solenoid valves control the start of injection and duration of injection for each UIS via additional fuel pressure lines. As the solenoid valves are not activated here with high pressure, rather with “controlling” fuel (18 bar), the injectors of the HPI system already work with pressures of approx. 2400 bar. The high injection pressures and exact electronic control enable a significant reduction in pollutant emissions. A requirement for this system, however, is an additional cam drive with overhead camshaft, which in turn has a one-piece, continuous cylinder head as a condition.


Unit pump system UPS

The unit pump system is also known by its abbreviation UPS. This system also has a separate injection module for each engine cylinder. A short high-pressure line connects each individual pump with the corresponding nozzle. The control system, drive system and maximum pressure of the UPS correspond to those of the UIS. However, the spatial separation of the pump and injection element of the UPS provide greater space for the construction of the engine. The UPS can also be used on engines without an overhead camshaft and thus without a continuous cylinder head. However, an additional cam drive is also necessary here. EXAMPLE Possible areas of application for the unit injector system (UIS) and the unit pump system (UPS) are passenger car and commercial vehicle engines with a maximum power output per cylinder of 70 kW and injection pressures up to 1800 bar. The unit injector systems are used, for example, by Scania and Volvo for commercial vehicle engines with displacements between 9 and 16 litres. Examples of the deployment of the unit pump system are the V6 and V8 engines with 11.9 or 15.9 litres of displacement in the heavy Mercedes-Benz series as well as the Mack engines with 12 litres displacement in the heavy Renault series.