Fuel injection nozzle for internal combustion engines

Details Fuel injection nozzle for internal combustion engines Fuel injection nozzle for internal combustion engines

1986-12-15

1989-01-31

Butler, Douglas C.

Fluid sprinkling, spraying, and diffusing

Fluid pressure responsive discharge modifier* or flow...

Fuel injector or burner

291567A, B21K 120

Patent

active

048010952

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The invention relates to a fuel-injection nozzle for internal combustion engines. In these injection nozzles the front cusp of the nozzle element is hardened, so that the inside positioned valve seat face withstands the impact stress by the valve needle and the outside positioned wall area is protected against abrasive wear by the gas flow in the combustion chamber. However, it is disadvantageous in that the breaking rigidity of the front cusp of the nozzle element is reduced due to this wear and due to the presence of the injection holes in the area of the valve seat face or in the region of a pocket hole which is provided adjacent to the valve seat face. This disadvantage can only be partially overcome by a corresponding dimensioning of the wall thickness of the front cusp, because also the length of the injection holes and thereby the injection nozzle formation is decisively influenced. The cross section and the length of the injection holes are fixed in tight limitations due to such injection characteristic values, like amount of injection fuel spraying and the like.


SUMMARY OF THE INVENTION

It is an object of the present invention to provide a fuel injection nozzle in which the front cusp of the nozzle element may have a higher break resistance than that in the known embodiments, without the valve seat face losing any hardness and without the protection of the outer wall area of the front cusp being unduly severly reduced against abrasive wear.
One embodiment has been shown to be particularly advantageous by means of tests, wherein the hardness of an outer wall area of the front cusp is lower by at least 100 HV1, preferably by 150 HV1 than the hardness of the inner wall area forming the valve seat face.
The rigidity of the front cusp may be effectively increased without any impairment of the other characteristics of the front cusp if, in accordance with the invention, the center wall area of the front cusp which is disposed between the valve seat face or the pocket hole surface and the opposite disposed wall area has a lower hardness than the outer wall area. Particularly good results are obtained with injection nozzles, wherein the hardness of the center wall area is lower by at least 100 HV1 than the hardness of the outer wall area. It has been shown to be optimal if the hardness of the center wall area is between 400 HV1 and 550 HV1.
Generally, the nozzle elements of injection nozzles are made from carburized steel which for the purpose of a high hardness is recarburized. The reduced hardness of the outer wall area of the front cusp being disposed opposite of the valve seat face or the pocket hole surface can be obtained in that the front cusp is not recarbonized on the outside or only slightly recarbonized, so that in the carbonized hardened state a sufficient flexible form changing characteristics is obtained on the outside of the cusp. Comparison tests have shown that the rigidity characteristics of the front cusp can thereby be already noticeably increased. The same success can be obtained if, instead of the carbonizing, a nitrifying or nitrocarbonization is performed, whereby other steels than carburized steels may be used, preferably alloyed heat-treatable steels or steals which are worked at red heat. In this case it is advantageous to anneal the nozzle before the nitrifying.
An additional reduction of the hardness in the center area with respect to the customary manufacturing results in a further improvement. This can advantageously be obtained in that the wall thickness of the front cusp is at first selected larger than the finished size and that only after the recarburization or nitrifying or nitrocarburizing of the inner and outer wall areas of the front cusp the finished size is obtained by deburring a partial layer of the recarburized or nitrified or nitrocarburized outer wall area and thereafter a hardening or in the case of the nitrifying or nitrocarburizing a second nitrifying or nitrocarburization is performed, if need be.
The break resistance of the

REFERENCES:
patent: 1775358 (1930-09-01), Smith
patent: 1956014 (1934-04-01), Fink et al.
patent: 1979910 (1934-11-01), Scott
patent: 2138528 (1938-11-01), Phillipps
patent: 3836080 (1974-09-01), Butterfield et al.
patent: 4035204 (1977-07-01), Hech et al.
patent: 4639568 (1987-01-01), Check et al.
patent: 4651926 (1981-03-01), Sasao et al.

Affiliated with

Also associated with

Rating

Fuel injection nozzle 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 nozzle for internal combustion engines, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fuel injection nozzle for internal combustion engines will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-174317