Fluid sprinkling – spraying – and diffusing – Fluid pressure responsive discharge modifier* or flow... – Fuel injector or burner
Utility Patent
1999-05-28
2001-01-02
Kashnikow, Andres (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Fluid pressure responsive discharge modifier* or flow...
Fuel injector or burner
C239S533120, C239SDIG001
Utility Patent
active
06168095
ABSTRACT:
PRIOR ART
The invention relates to a fuel injector for internal combustion engines. A nozzle body includes a valve needle with a sealing face which is movably supported whose needle comes into contact with a sealing face adapted to the needle that is embodied in an inner wall region of an end cup of the nozzle body. At least one injection opening is provided in this sealing face, wherein both the inner wall region, with the sealing face of the nozzle body disposed on it, and its outer wall region are hardened.
This kind of fuel injector for internal combustion engines is drawn, for example, from EP 0 233 190 B1. In that instance, the inner wall region of the end cup provided with the valve seat face, through boundary layer hardening, is provided with a greater hardness than the outer wall region and the central boundary region disposed between the valve seat face and the opposing outer wall region.
The nozzle body of these fuel injectors is comprised of case hardened steel, which is variously carbonized in order to develop the various hardness gradients.
Fuel injectors of this kind are used, for example, in diesel fuel injection systems, where they are subjected to very high temperatures. When diesel engines, namely those provided with a direct injection, are operated for motor braking, very high temperatures can be produced in the diesel fuel injectors, by means of which they can be “soft annealed” and as a result, can become unsuitable for further operation (wear, risk of fracture).
With the use of this type of fuel injectors in gasoline engines provided with direct injection systems, in addition to wear, problems also arise as a result of corrosion of the fuel injectors.
An object of the invention, therefore, is to improve a fuel injector of this generic type to such an extent that on the one hand, the fuel injector can be used at very high temperatures, wherein in particular, the soft annealing mentioned above in connection with diesel engines should be prevented, and that on the other hand, the improved fuel injector has a high degree of corrosion resistance so that it is also possible to use the fuel injector in gasoline direct injection systems. It should be possible to manufacture the fuel injector as simply and therefore inexpensively as possible.
ADVANTAGES OF THE INVENTION
This object is attained according to the invention with fuel injector of the type described at the beginning by virtue of the fact that the nozzle body is comprised of a rustproof martensitic steel, which is hardened by means of case hardening with nitrogen.
The improvement of the corrosion resistance of martensitic rustproof steels by means of case hardening with nitrogen is drawn, for example, from DE 40 33 706 A1. In the heat treating process disclosed by this reference, the main idea is to increase the corrosion resistance.
Based on a large number of trials, it has turned out that the heat treating process drawn from DE 40 33 706 A1 surprisingly can also be used to increase the temperature resistance of nozzle bodies. In particular, it has turned out that the above-described soft annealing of the nozzle body at high temperatures can be avoided through the use of a martensitic rustproof steel which has been hardened by means of case hardening with nitrogen.
It is particularly advantageous in this connection that the injection openings are also hardened.
Steels with the following composition can advantageously be considered as rustproof martensitic steels: <0.1, preferably 0.01 weight % C; from 0.03 to 0.3, preferably 0.1 weight % N; from 0.01 to 1.0, preferably 0.06 weight % Si; from 10.0 to 20.0 preferably 13.7 weight % Cr; <5.0, preferably 1.5 weight % Mo; <0.5, preferably 0 weight % Nb; <0.5, preferably 0.1 weight % V, and alloy additives for the suppression of &dgr;-ferrite.
In order to suppress the &dgr;-ferrite formation, preferably alloy additives of the following composition are added: from 0.01 to 1.0, preferably 0.03 weight % Mn; <5.0, preferably 2.2 weight % Ni; <5.0, preferably 2.7 weight % Co.
Up to now, no further information has been given with regard to the case hardening.
The nozzle body is advantageously hardened by means of case hardening at a temperature of 1050 to 1200° C., preferably 1100° C., at a pressure of 0.5 to 10 bar, preferably at 3 bar, over a time period of 1 h to 30 h, preferably 4 h.
Through such an embodiment of the nozzle body out of rustproof martensitic steel, which is hardened by means of case hardening with nitrogen as described above, not only are the corrosion and wear resistance significantly increased, but the retention of hardness and the red hardness are significantly increased as well.
The advantages in so doing are as follows: there is an improved ease of machining of the unhardened initial material. The boundary layer hardening takes place with a higher degree of manufacturing reliability, which leads to a more uniform surface hardness and hardness penetration, particularly also in the bores that constitute the injection openings, without the occurrence of cleaning problems. Based on a simple manufacture, the fuel injectors can be manufactured not only in a technically simple manner, but also in a particularly inexpensive manner, wherein no distinction has to be drawn between fuel injectors for diesel injection systems and fuel injectors for gasoline injection systems.
REFERENCES:
patent: 4801095 (1989-01-01), Banzhaf et al.
patent: 5492357 (1996-02-01), Fukushima et al.
patent: 4033706 (1991-02-01), None
Muehleder Friedrich
Seitter Max
Evans Robin O.
Greigg Edwin E.
Greigg Ronald E.
Kashnikow Andres
Robert & Bosch GmbH
LandOfFree
Fuel injector for an internal combustion engine 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 injector for an internal combustion engine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fuel injector for an internal combustion engine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2527534