JPH11148886A - Measuring apparatus for momentum of engine valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a measuring apparatus by which the actual motion of an engine valve is measured precisely when an engine is operated by a firing operation. SOLUTION: A cylindrical bobbin 16 which is concentric with an engine valve 1 and in which a sensor coil 15 is wound on its outer circumferential face is installed at a cylinder head 9. A core 17 which is concentric with the bobbin 16 and which is moved relatively in the direction of its axial line with reference to the bobbin 16 together with the engine valve 1 is installed at the engine valve 1. At this time, a displacement sensor 14 which detects the displacement in the engine valve 1 is formed of the bobbin 16 and of the core 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the momentum of an engine valve incorporated in a valve train of an internal combustion engine in a firing state by an actual engine.

[0002]

2. Description of the Related Art To increase the output of an engine, it is effective to increase the permissible rotational speed of the engine. However, the permissible rotational speed is naturally limited due to the problem of the ability of a valve train to follow a cam. . That is, the opening and closing movement of the engine valve is set in advance by the profile of the cam, and if the engine valve is operated according to the profile, gas exchange in the combustion chamber is performed accurately and reliably, thereby improving the engine performance. Can be. However, in fact, the higher the engine speed, the more difficult it is to operate the engine valve following the cam profile due to the inertial force due to the mass of the valve train components, It degrades engine performance by jumping while the engine valve is opening and closing or bouncing when seated.

[0003] From such a viewpoint, when the specifications of the components of the valve train are changed, the actual movement of the engine valve is measured, and the valve train components are evaluated based on the motion characteristics. In addition, the followability of the engine valve to the cam has been investigated. This measurement is usually
This is performed by detecting the movement of the engine valve or the spring retainer fixed thereto by a sensor.

At this time, in a direct acting type valve operating mechanism as shown in FIG. 3, not only the shaft end of the engine valve (1) but also
A spring retainer (3) fixed thereto via a cotter (2) is located in the cylindrical portion of the cup-shaped tappet (4), and a shim (5) is provided on the upper surface of the tappet (4). The cam (6) is in contact with the
It is very difficult to measure the movements of (1) and the spring retainer (3) with a sensor.

In order to execute this, it is necessary to form a groove or a hole for inserting a sensor in the shim (5) and the tappet (4). Is changed, the condition becomes different from the actual condition, and an accurate measurement result cannot be obtained.

Therefore, conventionally, a piston and a connecting rod are removed from a cylinder block of an engine,
As shown in FIG. 3, a non-contact type displacement sensor (proximity sensor) (8) is held by a suitable bracket 2 directly below the engine valve (1) in the cylinder head (7) and placed on a table. By motoring the engine, only the valve train was operated, and the displacement of the engine valve (1) on the umbrella front side was measured.

[0007]

The measurement by the conventional motoring described above does not measure the actual movement of the valve while the engine is in the filing operation, so that the engine pressure such as the combustion pressure in the cylinder is not measured. There is a problem that the influence on the behavior of the valve cannot be measured accurately. Another problem is that the conventional displacement sensor (8) cannot accurately measure the entire movement stroke of the engine valve (1).

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is capable of accurately measuring the actual movement of an engine valve during a firing operation of an engine, regardless of the type of a valve operating mechanism. It is an object of the present invention to provide an engine valve momentum measuring device.

[0009]

According to the present invention, the above-mentioned problem is solved as follows. (1) A device for measuring the momentum of an engine valve which is moved up and down with respect to a cylinder head by a valve operating mechanism, wherein a sensor coil is concentric with the engine valve and wound around an outer peripheral surface of the cylinder head. A cylindrical bobbin is provided, and an engine valve is provided with a core that is concentric with the bobbin and that moves up and down relative to the bobbin together with the engine valve. Is formed.

(2) In the above item (1), the core is formed of a non-magnetic material.

(3) In the above item (1) or (2), the sensor coil is a separate type differential transformer.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. The same members as those in the related art will be described with the same reference numerals. FIG. 1 shows a main part of a direct acting valve train to which the present invention is applied.

The shaft (1b) of the engine valve (1) is vertically slidably guided by a valve guide (10) pressed into a cylinder head (9). A spring retainer (3) is attached to the portion via a half cotter (2) as in the prior art. Washer (11) placed on top of spring retainer (3) and cylinder head (9)
Between them, a coil-shaped valve spring (12) is contracted. The valve spring (12) is substantially coaxial with the shaft (1b) of the engine valve (1), and is provided with a valve guide.
(10) and the shaft (1b) are arranged with a slight gap therebetween so as to surround the shaft (1b). (13) is a lip seal externally fitted to the upper end of the valve guide (10), which prevents oil dropping by contacting the outer peripheral surface of the shaft (1b).

At the upper end of the shaft (1b) of the engine valve (1), a tappet (4) similar to the conventional one is attached with a spring retainer.
A cam (not shown) abuts on the shim (5) fitted so as to cover (3) and fitted into the concave portion on the upper surface of the tappet (4). When this cam rotates, the engine valve
(1) is pushed down against the force of the valve spring (12), and the opening and closing movement is performed.

An annular space formed between the shaft portion (1b) and the valve guide (10) of the engine valve (1) and the valve spring (12) has a differential transformer type displacement sensor (1).
4) is incorporated so as to surround the engine valve (1).

That is, the displacement sensor (14) includes a bobbin (16) having a sensor coil (15) wound on the outer peripheral surface thereof, and a cylindrical core (outer diameter of which is slightly smaller than the inner diameter of the bobbin (16)). 17)
The bobbin (16) has a thick sheet portion (16
a) is press-fitted into the outer peripheral surface of the upper end portion of the valve guide (10), thereby being fixed concentrically with the engine valve (1).
The core (17) is held concentrically with the bobbin (16) by embedding the upper end thereof under the lower surface of the spring retainer (3), and the lower end thereof is provided when the engine valve (1) is not operated.
(When the valve is closed), it is located in the bobbin (16).

When the spring retainer (3) moves up and down integrally with the opening and closing movement of the engine valve (1),
As shown by the imaginary line in FIG. 1, the core (17) enters the bobbin (16) with a slight gap formed between the core and the inner surface thereof.

The bobbin (16) is made of stainless steel or bakelite, and the core (17) is made of a nonmagnetic metal material such as aluminum or copper.
The spring retainer (3) has its weight
, And the increase in inertial mass due to the attachment of the core (17) is eliminated. (18) is the coil (1
With the multi-core lead wire connected to 5), through the wiring groove (19) formed on the upper surface of the cylinder head (9),
It is led out of (12), and its end is connected to a measuring instrument main body (not shown).

The sensor coil (15) comprises a primary coil (15a) and a secondary coil (15b) wound closely thereon, as shown schematically in FIG. By providing a part of the next coil outside as a dummy coil (15c), a separated type differential transformer is configured. In this case, the total length of the bobbin (16) and the sensor coil (15) can be reduced. The separation-type differential transformer, is excited by the high frequency of 100-300KH _Z, large output voltage by the eddy current effects when moving the bobbin (16) of the non-magnetic core (17) is the sensor coil (15) can get. Thus, the momentum of the spring retainer (3), that is, the engine valve (1) integrated therewith can be measured with high accuracy.

As in the above embodiment, the displacement sensor (14)
If a high-frequency excitation type separation type differential transformer using a dummy coil is used, a high output can be obtained even if the number of turns of the secondary coil (15b) is small. ) And a small gap between the valve spring (12). In addition, the responsiveness and the linearity are improved, so that a slight behavior of the engine valve (1) can be accurately detected.

The present invention can be effectively applied to a comparatively small engine having a small storage space for the displacement sensor (14). However, for a large engine having a sufficient storage space, a normal differential transformer type displacement is used. Sometimes a sensor is used. In this embodiment, an example in which the present invention is applied to a direct-acting type valve operating mechanism is shown. However, it is needless to say that the present invention can also be applied to a rocker arm type or other valve operating mechanisms.

[0022]

According to the first aspect of the present invention, the bobbin around which the sensor coil is wound and the core can be compactly arranged concentrically with the engine valve.
Regardless of the type of the valve operating mechanism, the actual movement of the engine valve during the firing operation of the engine can be accurately measured without any trouble.

According to the second aspect of the present invention, a large output voltage is obtained by an eddy current effect when the non-magnetic core moves with respect to the sensor coil, so that an engine valve integrated with the core can be obtained. The amount of exercise can be measured with high accuracy.

According to the third aspect of the present invention, the number of turns of the secondary coil of the differential transformer can be reduced, so that the bobbin can be reduced in size and can be easily applied to a valve operating mechanism of a small engine having a small accommodation space. Can. In addition, since the responsiveness and the linearity are improved, even a slight behavior of the engine valve can be accurately measured.

[Brief description of the drawings]

FIG. 1 is an enlarged longitudinal sectional front view of a main part of a direct acting valve train incorporating an embodiment of the present invention.

FIG. 2 is a schematic diagram of a differential transformer.

FIG. 3 is a cross-sectional view showing a direct-acting valve train and a conventional measuring procedure.

[Explanation of symbols]

 (1) Engine valve (1b) Shaft (2) Cotter (3) Spring retainer (4) Tappet (5) Shim (6) Cam (7) Cylinder (9) Cylinder head (10) Valve guide (11) Washer ( 12) Valve spring (13) Lip seal (14) Displacement sensor (15) Sensor coil (16) Bobbin (16a) Seat (17) Core (18) Multi-core lead wire (19) Wiring groove

Claims (3)

[Claims] An apparatus for measuring a momentum of an engine valve which is moved up and down with respect to a cylinder head by a valve operating mechanism, wherein the cylinder head is concentric with the engine valve and a sensor coil is wound around an outer peripheral surface. A turned cylindrical bobbin is provided, and an engine valve is provided with a core that is concentric with the bobbin and that moves up and down relative to the bobbin together with the engine valve. An engine valve momentum measuring device, wherein a displacement sensor for detecting a displacement of an engine is formed. 2. The engine valve momentum measuring device according to claim 1, wherein the core is formed of a non-magnetic material. 3. The engine valve momentum measuring device according to claim 1, wherein the sensor coil is a separate type differential transformer.