Valves and valve actuation – Rotary valves – Butterfly
Reexamination Certificate
2000-03-10
2001-12-11
Shaver, Kevin (Department: 3754)
Valves and valve actuation
Rotary valves
Butterfly
Reexamination Certificate
active
06328281
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The invention relates in general terms to a device for controlling the mass flow rate of a liquid or gaseous medium and, in particular, to a throttle body in accordance with features.
Such devices are well known. DE 32 44 103 A1, for example, has disclosed a throttle body with a tubular housing, the housing having an overall cross section of flow bounded by an essentially circularcylindrical inner wall. When the flap mounted in the housing is rotated, the mass flow rate rises steeply with increasing rotation from a minimum position in the direction of a maximum position.
DE 43 19 015 A1 has likewise disclosed a device for controlling the mass flow rate in which the characteristic can be adapted within predeterminable ranges.
The disadvantage of these two devices, however, is that there is an excessive rise in the mass flow rate as the opening of the flap increases. As a result, there is a continuous increase in the mass flow rate over the working range of the flap, this being a disadvantage since the increase in the mass flow rate becomes too great as the opening of the flap increases. Particularly in the case of internal combustion engines in vehicles in which the power output is controlled by means of the position of the throttle flap, sensitive control of the power output is not possible if the air mass rises too steeply as the throttle flap is opened to an increasing extent.
SUMMARY OF THE INVENTION
The underlying object of the invention is therefore to provide a device for controlling the mass flow rate of a liquid or gaseous medium, in particular a throttle body, which avoids the disadvantages described at the outset and by means of which sensitive control or regulation of a process that can be varied by means of the setting of the flap can be achieved.
The configuration of the housing and/or the flap, by virtue of which an only slight change in the volume flow, in particular a slight increase in the volume flow, can be achieved over the range of motion (working range) of the flap, provides the advantage that, as the working range of the flap (opening of the flap) increases, the process influenced by the position of the flap is influenced only slightly and hence sensitive control and/or regulation of the process on the basis of the position of the flap is made possible. Thus, in a special configuration of the invention, an only slight change in the volume flow of up to 5% of the total mass flow rate changes, at least over a significant part of the working range of the flap amounting to 50% or more of the total working range. Over this significant part of the working range, the mass flow rate can increase or decrease.
A preferred area of application of the invention is in the field of power output control of internal combustion engines. However, other applications would also be conceivable where flaps are used in a tubular housing, e.g. for regulating the flow of liquids or regulating the air flow in air-conditioning systems in which fresh air or recirculated air or, alternatively, cold or heated air is to be fed to a passenger compartment of a vehicle.
In the text which follows, the invention is described with reference to a throttle body. To achieve the object it is provided, according to the invention, that upstream and downstream in the direction of flow and starting from a minimum position of the throttle flap, there extends a right cylindrical portion and adjoining the right cylindrical portion there is a spherical portion with a center which coincides at least approximately with the center of the throttle-flap shaft and with a radius which is greater than the radius of motion of the throttle flap. This has the advantage that it is possible with this configuration to achieve a characteristic where, starting from the minimum position, in particular the closed position, of the throttle flap, a steep rise in the mass of air passed through can be achieved in a small part of the working range, which is then followed by only a slight change (slight rise) in the air mass as the working range (opening) of the flap increases. This ensures that when a large volume of air is required by the internal combustion engine, this large volume can be made available to it, and sensitive regulation of the power output of the internal combustion engine is made possible in the adjoining range by virtue of the only slight increase in the air mass as the throttle flap opens further.
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Patent Abstracts of Japan, JP 3-15631 A, M-1098, Mar. 28, 1991 vol. 15/No. 129.
Bonderer David A
Farber Martin A.
Shaver Kevin
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