Fluid sprinkling – spraying – and diffusing – With solid means as guard or protector – Bumper or guard protects distributor
Patent
1992-02-19
1993-12-28
Kashnikow, Andres
Fluid sprinkling, spraying, and diffusing
With solid means as guard or protector
Bumper or guard protects distributor
2395332, 23953312, 2395851, F02M 6118
Patent
active
052732150
DESCRIPTION:
BRIEF SUMMARY
STATE OF THE ART
The invention is based on a fuel injection valve as set forth herein. In the German patent application P 39 27 390.3, a fuel injection valve has already been proposed in which a pan-shaped protective cap is provided. This cap has a passage opening in its bottom downstream of the at least one injection opening. The protective cap is intended to prevent damage in the region of the at least one injection opening and to avoid particles from the surroundings of the fuel injection valve, whose nozzle body protrudes into the induction pipe, from being deposited in the region of the at least one injection opening and leading to a restriction of the at least one injection opening. Such restriction would reduce the quantity of fuel injected in an undesirable manner. The narrow gap formed, by a contact section of the protective cap, between the bottom of the protective cap and an end surface of the fuel injection valve ensures that even in the case of fairly long periods of operation of the internal combustion engine, fuel deposits caused by the sequential operating and shut-down phases do not lead to the fuel quantity metered by the fuel injection valve being reduced in an undesirable manner.
If the internal combustion engine (and therefore also the fuel injection system) is shut down, the fuel injection valve is closed and fuel possibly present in the gap and the passage opening partially evaporates because of the strong heating from the internal combustion engine. In this process, only the constituents of the fuel which evaporate at relatively low temperatures are volatilised whereas the constituents which evaporate at higher temperatures are not sufficiently heated and move outwards in the gap in the radial direction because of the capillary effect of the narrow gap and are deposited there so that the at least one injection opening and the passage opening remain free from deposits.
Exact axial adjustment of the narrow gap, such as is necessary for the capillary effect, is not, however, always guaranteed by the contact section of the protective cap in accordance with the German patent application P 39 27 390.3. In addition, the manufacture of the protective cap is complicated for mass production purposes.
ADVANTAGES OF THE INVENTION
The fuel injection valve according to the invention has an advantage of simple and low-cost manufacture and the possibility of exact axial adjustment of the narrow gap, this exact adjustment being achieved in a simple manner by the protrusions. The narrow gap formed between the bottom of the protective cap and the end surface of the fuel injection valve exerts a capillary effect on the fuel and, in the case of fairly long periods of operation of the internal combustion engine, reliably prevents undesirable reduction by fuel deposits of the free flow cross-section of the at least one injection opening and the passage opening and, therefore, of the fuel quantity metered by the fuel injection valve. Advantageous extensions and improvements to the fuel injection valve given herein are possible by means of the measures listed.
It is of advantage for the protective cap to have a retention collar with at least two dimples formed in it protruding radially outwards at its end remote from the bottom. These dimples act to increase the strength of the retention collar, which acts as the side surface for a sealing ring.
It is particularly advantageous for the protective cap to be formed from a metallic material. The evaporation of the low boiling-point constituents of the fuel, which occurs after the internal combustion engine is shut down, and hence the deposit of the higher boiling-point constituents is substantially reduced by utilising the condensation effects of the fuel on the metallic protective cap.
For particularly simple and low-cost manufacture of the fuel injection valve according to the invention, it is advantageous for the protective cap to be formed by shaping sheet metal.
For a connection between the protective cap and the nozzle body which is reliable and can b
REFERENCES:
patent: 4057190 (1977-11-01), Kiwior et al.
patent: 4925111 (1990-05-01), Foertsch et al.
patent: 4957241 (1990-09-01), Roger
Hans Waldemar
Preussner Christian
Grant William
Greigg Edwin E.
Greigg Ronald E.
Kashnikow Andres
Robert & Bosch GmbH
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