| 摘要 |
The fuel injection device has a fuel pump with a pump piston (3) driven by a camshaft and delivering fuel into a pump chamber (4). The pump piston has one helix (10) determining the start of pumping and a second helix (11) determining the end of pumping, which both act in conjunction with one and the same aperture (12) in the cylinder wall. Attached to the pump chamber (4) is a conduit (16) leading to the overflow conduit (15), in which conduit (16) there is an overflow valve (17) on which the fuel pressure in the pump chamber acts in the closing direction. The pump piston (3) is fitted with at least a third helix (20) connected to the pump chamber (4), the helix acting in conjunction with a further aperture (28) in the cylinder wall. A fuel- filled chamber (30) connected to this further aperture (28) is connected to the overflow conduit (15) via a top-up valve (34) and a control valve (36). In the chamber (30) is a piston (31) to which the fuel is admitted, which operates in conjunction with the overflow valve (17) in such a way that, when pumping commences before the top dead centre, the overflow valve is temporarily opened during the pumping phase when the third helix (20) forms the connection between the pump chamber and the chamber (30) via the further aperture (28). Opening of the overflow valve (17) is terminated during the pumping phase by opening of the control valve (36). <IMAGE> |
