Internal-combustion engines – Charge forming device – With fuel pump
Patent
1994-04-05
1995-03-14
Miller, Carl S.
Internal-combustion engines
Charge forming device
With fuel pump
123501, 417494, 417499, F02M 3704, F02B 704
Patent
active
053968719
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
The invention is based on a fuel injection pump as defined hereinafter. In one such fuel injection pump, known from German Patent Disclosure DE-OS 2 246 056, in which a pump piston whose end face defines a pump work chamber is moved axially in a cylinder liner, the control edge on the face end of the pump piston, which edge by overtaking a control opening disposed in the cylinder wall controls the injection onset, is slanted relative to the control opening. In the rotary positional range of the pump piston that controls the rated load range of the internal combustion engine to be supplied, in such a way that the injection onset in this range is delayed in the direction of a later onset. This makes it possible not only to optimize the injection onset for the high-load range but also to achieve a high maximum combustion pressure in the pump work chamber in the other operating points as well, because these points can now be adapted independently of the rated load range. With the known fuel injection pump, it is thus possible to increase the maximum combustion pressure over the entire operating range of the fuel injection pump, without exceeding the maximum allowable limit value for the mechanical loadability of the components.
In designing the known fuel injection pump for emission-optimized engines, however, the injection onsets must be shifted to so late that in the cold state of the engine in the lowermost load range, or at zero load, white smoke is emitted, which in that operating state increases the pollutant emissions of the engine to be supplied.
ADVANTAGES OF THE INVENTION
The fuel injection pump according to the invention has the advantage over the prior art that by the design of the pump piston control edge that controls the supply onset and hence the injection onset, with indented regions, a shift of the supply onset to early is performed at zero or low load and as a function of the temperature, and as a result white smoke in the warmup phase of the engine can be avoided without requiring an additional external injection timer for that purpose.
By embodying the control edges with a specific shape to form two regions, so that for the operating range involving the cold engine operated at low or zero load, a control region with an extreme shift toward early takes effect, while at higher load or temperature the shift toward early of the supply onset is less extensive, because of the other control region. In this way it is possible to vary the extent of the shift toward early above all in the idling mode as a function of the operating temperature and load of the engine, and thus to adjust the optimal supply onset for the various operating ranges. Another advantage is attained by separating the control edges from one another by means of a longitudinal groove; thus both control edge regions are separated exactly from one another, which enables proper association of a separate pump performance graph. The abrupt transition from control edge to control edge via axially parallel edges has the further advantage, in the fuel injection pump according to the invention that the individual governing locations can be rapidly triggered by discontinuity functions, so that an accurate association with the various governing ranges is possible.
A further advantage is attained in that the switchover between the control edge regions and thus between the pump performance graphs takes place as a function of temperature and load in electrically governed fuel injection pumps via a simple logic circuit, which moreover takes into account the hysteresis occurring in the governing cycle, resulting in not only less expense for control, but also high flexibility in terms of the limit value specifications.
Further advantages and advantageous features of the subject of the invention may be learned from the drawing, description and claims.
DRAWING
An exemplary embodiment of the subject of the invention is shown in the drawing and will be described in detail below.
FIG. 1 shows a detail of the fuel injection pump accord
REFERENCES:
patent: 1926743 (1933-09-01), Hill
patent: 1966694 (1934-07-01), Vaudet
patent: 2159177 (1939-05-01), Ricardo
patent: 2575955 (1951-11-01), Hatch
patent: 2810375 (1957-10-01), Froehlich
patent: 4013055 (1977-03-01), Sommer
patent: 4757794 (1988-07-01), Hofer
patent: 4975029 (1990-12-01), Hatz
patent: 5097812 (1992-03-01), Aogostin
patent: 5135367 (1992-08-01), Finsterwalder
patent: 5219280 (1993-06-01), Yashiro
Faupel Werner
Heck Dieter
Seher Dieter
Greigg Edwin E.
Greigg Ronald E.
Miller Carl S.
Robert & Bosch GmbH
LandOfFree
Fuel injection pump for internal combustion engines does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fuel injection pump for internal combustion engines, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fuel injection pump for internal combustion engines will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-707956