JPS6127692B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for an automobile engine, and more particularly to an intake system for an engine equipped with a supercharger and a Karman vortex flowmeter for detecting the amount of intake air taken into the supercharger. It is about improvement.

A Karman vortex flow meter, which detects the frequency at which Karman vortices occur using ultrasonic waves, is used as an intake air amount detection device for automobile engines. When detecting the Karman vortex using this method, a vortex detector configured to transmit ultrasonic waves from an ultrasonic oscillator through the intake air flow, modulate the Karman vortices, and receive them at a receiver is used. used. Therefore, when ultrasonic waves other than the ultrasonic waves emitted from the ultrasonic transmitter propagate into the flow of the intake air, they become so-called noise, which obstructs the detection of the Karman vortices.

Normally, such noise is negligible, but if a supercharger is installed downstream of the Karman vortex flowmeter, the ultrasonic waves generated from the supercharger wheel rotating at high speed will be at a level that cannot be ignored. In such cases, it becomes impossible to detect the Karman vortex.

In order to prevent ultrasonic noise generated by the supercharger from propagating to the Karman vortex detection unit, the present invention provides a second inlet air conduit located approximately perpendicular to the flow of intake air in the intake air conduit between the Karman vortex flowmeter and the supercharger. A vortex generator is installed,
The vortex generated by the vortex generator attenuates and scatters the propagation of the ultrasonic noise, and provides an intake system for the engine that can stably detect the Karman vortex even in an engine equipped with a supercharger. It is something to do.

The figures will be explained below. FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a diagram showing another embodiment of the invention. In the figure, 1 is an air cleaner case, 2 is an air intake port, 3 is an air cleaner element (paper), and 4 is a measurement conduit of a Le Mans vortex flow meter. A vortex detector 7 is provided that detects the frequency at which Karman vortices occur using ultrasonic waves. Reference numeral 8 denotes a branch pipe for flowing intake air bypassing the measurement conduit 4. 9 is an intake air conduit whose inner wall is made of sound absorbing material 10 that absorbs and attenuates ultrasonic waves.
(for example, non-woven fabric). 11 is a second vortex generator disposed in the intake air conduit 9 substantially perpendicular to the flow of intake air, 12 is a rubber hose for the intake air conduit, 13 is the main body of the supercharger, and 14 is the inlet of the supercharger. , 15 is a supercharger outlet connected to the intake pipe of the engine (not shown), 16 is an intake side impeller for pumping intake air, and 17 is an exhaust side impeller, from the exhaust inlet 18 connected to the exhaust pipe of the engine. It is rotated by the introduced exhaust gas and drives the intake side impeller 16 to rotate. 19 is an exhaust outlet.

In the above configuration, when the engine (not shown) is started, the intake air of the engine is introduced into the air cleaner 1 from the air intake port 2 and the cleaner element 3
The amount of intake air is detected by the measurement conduit 4 of the Karman vortex flowmeter, and the rubber hose 1 is connected to the intake air conduit 9.
2, is guided from the supercharger inlet 14 to the supercharger outlet 15, and is introduced into the intake pipe of the engine. In the operating state of the engine in which the amount of exhaust gas of the engine increases and the exhaust-side impeller 17 rotationally drives the intake-side impeller 16, the intake air is forced into the intake pipe of the engine by the intake-side impeller 16. Become. At this time,
The ultrasonic waves contained in the wind noise of the intake wheel 16 rotating at high speed propagate through the rubber hose 12 and the intake air conduit 9, and then propagate into the measurement conduit 4 of the Karman vortex flowmeter, where it is detected by the vortex detector. 7 as ultrasonic noise. However, the second vortex generator 11
The vortices generated thereby have the effect of attenuating and scattering the propagation of the ultrasonic noise, and the scattered ultrasonic waves are further absorbed and attenuated by the inner wall of the intake air conduit 9 made of the sound absorbing material 10. As a result, the ultrasonic noise is prevented from reaching the measurement conduit 4.

The second vortex generator 11 is arranged downstream of the measurement conduit 4 as shown in the embodiment of FIG. The effects of the present invention can be obtained even if the structure is configured as follows. Although the second vortex generator 11 is shown as a triangular prism, it may be a square prism, a cylinder, or a flat plate. Also, it is effective if the surface of the second vortex generator 11 is made of a sound-absorbing material such as a nonwoven fabric. It is.

As described above, the present invention provides an intake system for an engine configured to detect the amount of intake air taken into a supercharger using a Karman vortex flowmeter equipped with an ultrasonic vortex detector. A second vortex generator is disposed in the intake air conduit between the turbochargers and is substantially perpendicular to the flow of the intake air, and the ultrasonic noise propagating from the turbocharger is transmitted to the second vortex generator. The ultrasonic noise is attenuated and scattered by the vortices generated by the body, and the ultrasonic noise is absorbed and attenuated by the sound-absorbing material forming the inner wall of the intake air conduit, so the amount of air sucked into the supercharger can be stably detected. It has the extraordinary effect of being able to

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the invention, and FIG. 2 is a block diagram showing another embodiment of the invention. In the figure, 1 is an air cleaner case, 4 is a measurement conduit of a Karman vortex flowmeter, 6 is a vortex generator, 7 is a vortex detector, 8 is a flow pipe, 9 is an intake air conduit, 10 is a sound absorbing material, and 11 is a second 13 is a supercharger. The same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A supercharger that includes a vortex generator and a vortex detector that uses ultrasonic waves to detect the generation frequency of the Karman vortex generated by the vortex generator, and In an engine intake system equipped with a Karman vortex flowmeter that detects the amount of intake air flowing into the engine, a second air intake system is provided in the intake air conduit between the Karman vortex flowmeter and the supercharger, and the intake air flow is substantially perpendicular to the flow of the intake air. An intake system for an engine, characterized in that a vortex generator is provided so that ultrasonic waves propagating from the supercharger are attenuated and scattered by vortices generated by the second vortex generator. 2. An intake system for an engine according to claim 1, wherein the inner wall of the intake air conduit near the second vortex generator is made of a sound absorbing material that absorbs and attenuates ultrasonic waves. 3. The Karman vortex flow meter is equipped with a measurement conduit in which a vortex generator and a vortex detector are arranged, and a branch pipe that bypasses the measurement conduit, and a second vortex generator is arranged downstream of the measurement conduit. An intake system for an engine according to claim 1 or 2, characterized in that: