Internal-combustion engines – Charge forming device – Fuel injection system
Patent
1991-07-22
1992-11-10
Cross, E. Rollins
Internal-combustion engines
Charge forming device
Fuel injection system
123502, 123373, F02D 3100, F02M 4100, F02M 3704
Patent
active
051615096
DESCRIPTION:
BRIEF SUMMARY
STATE OF TECHNOLOGY
The invention is directed to a fuel injection pump of a distributor type construction for internal combustion engines.
A fuel injection pump of this type (DE 37 44 618 C1) is known where the throttle cross-sectional area is set in such a way that it increases with increasing displacement of the governor sleeve from the full load position to the no-load or idling position. With the respective throttle cross-section, the fuel pressure in the pump body is progressively lowered. Thus, the control pressure operating on the injection timing piston drops, and the injection timing piston of the injection timing mechanism, which is under the restoring force of a return spring, is pushed back and adjusts the start of delivery, and thus the start of injection, progressively in the direction of "late". The outlet duct for the discharge of fuel from the pump body, for the purpose of reducing the control pressure, extends in the interior of a so-called governor axis on which the governor sleeve slides, and is connected with a radial hole which opens out at the perimeter of the governor axis The various throttle cross-sections are set via two radial holes in the governor sleeve which are spaced at such an axial distance from one another that with progressive displacement of the governor sleeve, first one and then both holes are linked with the radial holes of the controller axis.
ADVANTAGES OF THE INVENTION
The fuel injection pump in accordance with the invention has the advantage that, starting from the full load position with progressive relief of the engine load, the start of the injection timing is adjusted to "late", but that at the no-load point or at idling, the start of injection is once again set to "earlier", albeit not quite so "early" as the start of injection under full load condition. By this means, good fuel processing and combustion is ensured, and clean exhaust is achieved in all load ranges.
As set forth, three different variations are given of how in the three load positions "full load", "part-load", "no-load" or "idling", the desired setting of the relief throttle can be set by displacing the governor sleeve. Here, the design of the device has the advantage that the load ranges can be relatively easily varied in size and position, even retrospectively, with the amount of final adjustment required being relatively small. In the examples set forth, these load ranges are given as fixed values, and cannot be subsequently altered, however, the construction costs are lower.
DRAWING
The invention is explained in more detail below, by means of the design examples represented in the drawing. The figures show the following:
FIG. 1 shows a longitudinal section of a fuel injection pump of the distributor type construction, schematically represented;
FIG. 2 shows part of a longitudinal section of the governor sleeve and the governor axis for the fuel injection pump in an enlarged view in FIG. 1;
FIGS. 3a, 3b, and 3c show part of a longitudinal section of the governor sleeve and the governor axis in accordance with a further example in three different displacement positions of the governor sleeve;
FIG. 4 shows part of an opened-up view of the sleeve of the governor sleeve in FIG. 3;
FIGS. 5a, 5b, and 5c show an enlarged part view of a longitudinal section of the governor axis with the respective opened-up view of the outer sleeve of the governor sleeve, in accordance with a third example in three different displacement positions of the governor sleeve;
FIG. 6 shows a diagram of the control pressure progression p.sub.i in the pump body of the fuel injection pump in FIG. 1, in relation to the displacement path s.sub.M of the governor sleeve, in the case of a governor sleeve in accordance with FIG. 2;
FIG. 7 shows a diagram of the progression of the control pressure p.sub.i in the pump body of the fuel injection pump in accordance with FIG. 1, in relation to the displacement path s.sub.M of the governor sleeve, in the case of a governor sleeve in accordance with FIGS. 3a, 3b, and 3c, or FIGS
REFERENCES:
patent: 4483297 (1984-11-01), Eheim et al.
patent: 4509470 (1985-04-01), Ito et al.
patent: 4513715 (1985-04-01), Braun et al.
patent: 4548184 (1985-10-01), Laufer et al.
patent: 4615317 (1986-10-01), Bofinger et al.
patent: 4699108 (1987-10-01), Rouse et al.
patent: 4819606 (1989-04-01), Kawano et al.
Krieger Klaus
Russeler Karl-Friedrich
Scharf Michael
Cross E. Rollins
Greigg Edwin E.
Greigg Ronald E.
Moulis Thomas N.
Robert & Bosch GmbH
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