JPS6142090Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a vibration detection device for detecting engine vibration and the like.

In general, automotive engines supply a lean air-fuel mixture to the engine in order to reduce harmful components in exhaust gas and improve fuel efficiency when the engine is operating, especially when idling. If the air-fuel mixture is made too lean, there is a risk that the air-fuel mixture will misfire. Therefore, by detecting the vibrations generated in the engine due to this misfire, it is possible to determine how lean the mixture can be; however, when determining the concentration of the mixture in this way, It is necessary to accurately detect engine vibration.

Conventionally, as shown in Utility Model Application Publication No. 52-49203, a member that comes into contact with the engine body and is displaced in accordance with the engine vibration is provided as a device for detecting engine vibration, and a member is provided at a certain distance from the member. Some devices detect vibration through contact between a contact point and the above-mentioned member. In this case, the presence or absence of vibration is only checked by detecting the generation of a signal due to contact, but there is a problem in that the magnitude of vibration cannot be detected.

Therefore, in order to be able to detect the magnitude of vibration, a housing with a coil wound around the outer periphery and a magnet loosely inserted inside is attached to the engine. It is conceivable to extract the displacement generated in the coil as an electromotive force and use this to detect engine vibration.

By the way, this type of engine vibration detection device
Because only the magnet is inserted loosely into the space inside the housing, durability is poor, as when the engine vibrates strongly, the magnet collides violently with the side wall of the housing and is damaged, and even small vibrations can cause the magnet to damage the housing. The problem is that the magnitude of the amplitude of engine vibration cannot be detected accurately.

Therefore, in order to be able to accurately detect the magnitude of the amplitude of engine vibrations, the dimensions of the housing should be made longer so that the magnets do not hit the side walls of the housing. Space is required.

This idea was created in view of the above-mentioned conventional problems.The housing is filled with oil, and the damping effect of this oil's viscosity is used to reduce the relative displacement between the magnet and the coil. By doing so, we provide a vibration detection device that shortens the dimensions of the housing to reduce the installation space, reduces the impact received when the magnet collides with the side wall of the housing, improves durability, and improves detection accuracy. It is intended to.

An embodiment of the present invention will be described below with reference to the drawings.

The drawing shows an engine vibration detection device according to an embodiment of the present invention, and in the drawing, reference numeral 1 denotes a housing having a cylindrical space 2 therein. An aluminum plate 5a for reinforcement is provided on the left side of the housing 1 in the drawing, and an aluminum plate 5b for reinforcement is provided on the right side of the housing 1 via a rubber plate 6. The housing 1, together with the aluminum plates 5a, 5b and the rubber plate 6, is attached to the side wall 4a of the engine body 4 by bolts 3.

Further, a magnet 7 is loosely inserted into the inner space 2 of the housing 1. The rubber plate 6 is provided to prevent the magnet 7 from adhering to the side wall 4a of the iron engine body 4. Furthermore, the space 2 of the housing 1 is filled with silicone oil 8 whose viscosity hardly changes with temperature changes and whose viscosity deteriorates little due to temperature changes. Further, a coil 9 is wound around the outer periphery of the housing 1, and an oscilloscope 10 is connected to one end of the coil 9.

Next, the effects will be explained.

In this engine vibration detection device 11, when large engine vibrations occur due to misfire of the air-fuel mixture, the housing 1 and the coil 9 vibrate greatly in the same way as the engine. At this time, since the magnet 7 is loosely inserted into the housing 1, a relative displacement occurs between the magnet 7 and the coil 9 due to the static inertia of the magnet 7, but the housing 1 is filled with silicone oil 8. Therefore, due to its viscosity, the amount of relative displacement becomes smaller than when the housing is filled with nothing. Therefore, even if the engine vibration is large, the magnet 7 will almost never hit the aluminum plate 5a or the rubber plate 6 that forms the side wall of the housing 1, and even if it does, the impact will be very small and the magnet 7 will be damaged. There is little to do, and its durability is greatly improved. In addition, since the relative displacement between the magnet 7 and the coil 9 is small, the dimensions of the housing 1 can be short.
The device becomes smaller and its installation space becomes smaller.

In addition, when the engine vibration is small, the vibration of the magnet 7 is also small, and the above-mentioned relative displacement amount is naturally smaller than when the engine vibration is large, and the electromotive force generated in the coil 9 is also naturally small, which changes the amplitude of the engine vibration. can be detected with high accuracy.

In addition, high-frequency minute vibrations such as wheel vibrations cause engine 4
When the signal is transmitted to the housing 1 through There is almost no displacement, and almost no electromotive force is generated in the coil 9. Therefore, this device 11 has the effect of not detecting high-frequency minute vibrations such as wheel vibrations, but only detecting engine vibrations with high precision.
The reliability of its detection is greatly improved and is very useful in determining how lean the mixture can be.

In the above embodiment, silicone oil was used as the oil filled into the housing, but other oils may be used. Further, in the above embodiment, the electromotive force of the coil is detected by an oscilloscope, but this may be detected by other means. Further, although the above embodiment describes the case of detecting engine vibration, this invention can also be applied to detecting vibration of any other vibrating body.

As described above, according to the vibration detection device of the present invention, the housing is filled with oil and the viscosity of this oil reduces the relative displacement between the magnet and the coil, so the installation space can be reduced. This can reduce magnet damage and improve durability.
Furthermore, when applied to detecting engine vibrations, for example, there is an effect that only engine vibrations can be detected with high accuracy without detecting high-frequency minute vibrations such as axle vibrations.

[Brief explanation of the drawing]

The drawing is a schematic diagram of an engine vibration detection device according to an embodiment of the present invention. 1...Housing, 2...Space, 4...Engine body (object to be detected), 7...Magnet (magnetic material), 8...
...Silicone oil (oil), 9...Coil.

Claims (1)

[Scope of utility model registration request] A housing that has a cylindrical space inside and is attached to the object to be detected, a magnetic material loosely inserted into the space of the housing, oil filled in the space of the housing, and an oil wound around the outer periphery of the housing. A vibration detection device comprising: a coil that generates an electromotive force proportional to the magnitude of vibration of the object to be detected through relative displacement with the magnetic body.