Fuel injection pump for diesel internal combustion engines

Details Fuel injection pump for diesel internal combustion engines Fuel injection pump for diesel internal combustion engines

1992-02-18

1993-05-11

Cross, E. Rollins

Internal-combustion engines

Charge forming device

With fuel pump

123299, F02M 3704

Patent

active

052092089

DESCRIPTION:

BRIEF SUMMARY
STATE OF TECHNOLOGY

The invention relates to a fuel injection pump for diesel engines, for the purpose of delivering an amount of fuel, divided into a pilot and a main jet injection quantity, in accordance with features set forth herein.
In the case of modern diesel engines, in particular those with direct injection processes, it is imperative, due to legislative requirements, and because of increased usage of diesel engines due to their favourable fuel consumption and lower fuel costs, that the irritating combustion noises be reduced, whilst their most favourable fuel consumption and exhaust gas values are maintained.
It is well known from the literature and from the results of test rig and road trials, that a noticeable reduction of noise in all load and speed ranges in diesel engines operating with direct injection, can be attained only by injecting an amount of fuel divided into pilot and main jet proportions. In order not to increase the black smoke, which is abhorred in diesel engines, or the hitherto favourable consumption, by pilot injection, the correct pilot injection amount and the correct interval, as determined in trials, between pilot injection and main injection must be precisely adhered to. Although the optimum pilot injection amount and the optimum injection or delivery interval between the pilot and the main injection differ, depending on the load and the speed, a useful compromise can be reached with regard to noise reduction on the one hand and the emission and consumption values on the other hand, by means of a small constant pilot injection volume and a constant delivery interval. An optimum result can be achieved only with two individually controlled fuel injection pumps and the associated injectors or twin injectors for the pilot and the main injection. Such equipment would be too costly and too bulky, and cannot therefore be used with small and medium-sized diesel engines, particularly when these are mounted in vehicles, and in view of this fact, solutions using a single fuel injection pump have been sought for decades.
From German DE-PS 736 684, for example, a fuel injection pump of the construction type in accordance with the generic type is known which has a pump plunger which, for the purpose of delivering the pilot and main injection volumes, and controlling the delivery interval between them, is equipped with a shoulder containing the first control edge, a recess forming the inclined control edge, and a transverse groove controlling the interruption, and which has a pump cylinder which apart from two control holes at different heights, has a separate relief duct which, controlled by the transverse groove, directs the relief fuel into the spring space of the injector during the delivery interval, and there contributes to an increase in pressure. To this end, the transverse groove, which is permanently connected with the pump chamber, controls an additional control aperture in the wall of the pump cylinder. In this arrangement, a disadvantage is that the duration of the delivery interval cannot be made smaller than the duration of the interruption, which results from the sum of the stroke portions determined from the width of the transverse groove and the diameter of the additional control aperture. Since the minimum width of the transverse groove and the diameter of the corresponding control aperture can be determined without noticeable throttling by the intermediate delivery volume which flows through during the maximum full load speed, the desired short period of interruption cannot be realised by the known pump. Moreover, a much too large lift of the injection pump cam, limited by the design, is used; and since there is only one recess, limited by an inclined control edge, the surfaces, which are arranged on opposite sides of the pump plunger with separation, and which are subjected to high pressure during injection, create a very high lateral pressure and a tilting moment at the pump plunger, since only one recess, limited by an inclined control edge, is present. Thus, du

REFERENCES:
patent: 3677256 (1972-07-01), Regneault et al.
patent: 4367706 (1983-01-01), Scheying
patent: 4480623 (1984-11-01), Thomas
patent: 4705005 (1987-11-01), Guntert et al.
patent: 4721442 (1988-01-01), Tanaka
patent: 4830587 (1989-05-01), Guntert et al.
patent: 4881506 (1989-11-01), Hoecker
patent: 4957418 (1990-09-01), Pischinger et al.
patent: 4964789 (1990-10-01), Schueler et al.
patent: 4975029 (1990-12-01), Hatz
patent: 5097812 (1992-03-01), Augustin

Affiliated with

Also associated with

Rating

Fuel injection pump for diesel 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 diesel 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 diesel internal combustion engines will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1343741