Measuring and testing – Simulating operating condition – Marine
Patent
1991-03-01
1992-12-01
Myracle, Jerry W.
Measuring and testing
Simulating operating condition
Marine
7320421, G01M 1900
Patent
active
051671476
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
The invention starts from an air-measuring device as set forth hereinafter.
Such air-measuring devices are known, for example, from DE 32 00 507 A1, U.S. Pat. No. 4,494,405, DE 29 14 275 C2, EP 0 087 621 B1 or EP 0 054 887 B1. The temperature-dependent measuring resistor used there, for example a hot wire or hot film, changes its electrical resistance as a function of the change of the air flow in the bypass channel. The output signal of the measuring resistor is thus a measure of the air flow rate in the main flow channel. In such air-measuring devices, the signals picked up across the measuring resistor are in part very noisy, making an expensive electronic signal processing system necessary in order to obtain sufficiently accurate measured values.
ADVANTAGES OF THE INVENTION
In contrast, the air-measuring device according to the invention, has the advantage that the noise component superposed on the actual measured value signal is considerably reduced and the measured value signal is largely unaffected by structural conditions in the airmeasuring device.
In particular, in an air-measuring device having a function characteristic or a characteristic shape with sufficiently high resolution is obtained
In an air-measuring device having, the influence of the different opening angles of the throttle valve on the measured value signal is n particular eliminated.
DRAWING
The invention is explained in greater detail in the description which follows, with reference to illustrative embodiments depicted in the drawing, in which:
FIGS. 1 and 2, each show a longitudinal section of an air-measuring device for an intake system of an internal combustion engine according to two illustrative embodiments,
FIG. 3 shows a plan view of the air-measuring device in FIG. 2.
DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS
In the air-measuring device to be seen in longitudinal section in FIG. 1, 10 denotes a so-called throttle body, in which a main Ilow channel 11 and a bypass channel 12 are formed. The -hrottle body 10 either forms part of the air intake pipe of an internal combustion engine or is connected to the latrer on the inlet side. On the outlet side, the throttle body 10 is attached to an intake manifold of the internal combustion engine.
To form main flow cnannel 11 and bypass channel 12, a through hole 13 is made in the throttle body 10, said hole consisting of two holes 131 and 132 arranged one after the other in the axial direction. Hole 132 has a larger diameter than hole 131 and is made eccentrically to the latter in the throttle body 10 so that the axes of the two holes 131,132 run parallel to one another with the eccentricity e. Inserted coaxially to hole 131 in hole 132 is a flow tube 14, which is supported at the front end against a stop face 15 in the transition between the holes 131,132 and is held in the axial direction by a retaining ring 16, which rests in a retaining groove 17 in the inlet region of the throttle body 10. A filter or a flow straightener 18 and a spacer ring 19 are furthermore clamped between retaining groove 17 and flow tube 14. Hole 131 and the flow tube 14, which is inserted coaxially to the latter and is smaller in diameter than the inside diameter of hole 132, together form the main flow channel 11, while the outer surface of the flow tube 14 delimits the bypass channel 12 together with the hole wall of hole 132. Arranged in the main flow channel 11, in the cylindrical region of bore 131, is a throttle valve 20, which is secured on an actuating shaft 21. The actuating shaft 21 is swivellably mounted in bearings 22,23 in the throttle body 10. The inner wall of the flow tube 14 is of venturi-shaped design and forms a venturi-shaped flow section in the main flow channel 11, referred to below as venturi section 24. This venturi section 24 has a minimum flow cross-section 25 at the end turned towards hole 131 and widens towards the inlet side of the throttle body 10.
Arranged in the bypass channel 12 is a temperaturedependent measuring resistor 26, which can be designed as a
REFERENCES:
patent: 4418568 (1983-12-01), Surman
patent: 4612895 (1986-09-01), Kuroiwa et al.
Bosch Walter
Frank Kurt
Gmelin Karl
Peters Klaus-Juergen
Schwegel Thomas
Greigg Edwin E.
Greigg Ronald E.
Myracle Jerry W.
Robert & Bosch GmbH
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