Sensor for the detection of the first cylinder of an internal combustion, engine with fuel injection.

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to a first cylinder detector of a gasoline internal combustion engine.

【0002】

[Conventional technology]

This type of detector aims to initialize the injection into a predetermined cylinder, called the first cylinder, in order to inject gasoline into the cylinders of the engine in the proper order.

【0003】

The first cylinder detector is essential for both dynamically computer controlled engines and statically ignited engines. In addition, it is necessary to initialize the injection function by the computer, in other words, in all the engines equipped with the computer ignition system.

【0004】

[Problems to be Solved by the Invention]

The present invention is a first cylinder detector specifically equipped in combination with a permanent magnet and equipped with a unipolar Hall effect pickup made of a soft magnetic material and arranged to detect the passage of a non-permanently magnetized target. The detection relates to a first cylinder detector that detects when a target passes through a pickup and a permanent magnet by crossing (connecting a ring) the magnetic field lines from the permanent magnet to the pickup. As a target, a protrusion is provided on the pulley body connected to the camshaft of the engine, and is generally used corresponding to the top dead center of the first cylinder (the position of the upper end of the piston movement).

【0005】

When the target 14 passes through the detector, the detection band of the Hall effect pickup undergoes a change in the magnetic flux to be detected. In fact, if this change in magnetic flux is insufficient in proportion to the permanent leakage magnetic flux leaking between the pickup and the permanent magnet, this change in magnetic flux cannot be detected. In other words, unless the permanent magnet is moved disproportionately with respect to the pickup, the magnetic induction in the absence of the target is too large to be detected compared to the state change of the hall circuit when the target to be detected passes. Is. In other words, this type of first cylinder detector is reliable only if the gap between the target 14 and the pickup is very narrow, less than about 0.2 mm.

【0006】

A previously proposed measure to increase this gap is to have double pickups, which allows the two pickups to work with one of the permanent magnets. The output signal from the pickup closest to the target passage is modulated, and the output signal from the other pickup is unmodulated. Moreover, by adding the output signal from the pickup, the passage of the target can be detected up to a gap of about 1 mm. However, this is a reluctant preparatory work. This is because this task requires two pickups of the same sensitivity, which is difficult to achieve. The present invention is intended to solve the above problems.

【0007】

[Means for solving problems]

An object of the present invention is to disclose the following detectors. That is, it is arranged to detect the passage of a target (14) made of a soft magnetic material that can move according to the displacement of the piston in the first cylinder of a gasoline internal combustion engine, and the target (14) is a permanent magnet (4). A first cylinder detector (9) for a gasoline internal combustion engine with a unipolar Hall effect pickup (3) intended to cross the magnetic field lines into the detection band of the pickup (3). Disclosed is a first cylinder detector for a gasoline internal combustion engine, characterized in that it comprises means (4, 5) arranged to cancel residual magnetic induction in the pickup (3).

【0008】

[Action]

The contribution of the present invention allows the pickup to detect changes in magnetic flux, even if the change in magnetic flux caused by the passage of the target (14) is small, regardless of the size of the distance between the pickup and the target. It was. The reason is that the residual induced magnetism exerted on the pickup when the target is not in the pickup position is virtually 0 (zero).

【0009】

In a preferred embodiment of the detector of the present invention, two permanent magnets are used, magnetic fields of the same amplitude and opposite polarity are formed, and are arranged symmetrically with respect to the detection band of the pickup. Since it is easy to make two magnets with the same characteristics unlike two pickups with the same characteristics, the magnetic fields with the same characteristics value by the two permanent magnets in the detector of the present invention repel each other. As a result, the induced magnetism in the detection band of the pickup cancels each other out. In that case, it is advantageous to arrange the pickup and the two permanent magnets as follows. That is, only one permanent magnet and pickup, of which the magnetic field is dominant among the two permanent magnets and sufficient to create the change in the induced magnetic field required for detection, is exposed to the action from the target. Are arranged in.

【0010】

[Preferable Embodiment]

For a more thorough understanding of the present invention, preferred embodiments of the detector of the present invention will be described below with reference to the drawings.

【0011】

In FIG. 1, the first cylinder detector 1 is installed on a printed wiring board 2, and a component that processes a detection signal is installed on one side of the printed wiring board (not shown) in a conventional manner. On the other surface of the printed wiring board, all three of the unipolar Hall effect pickup 3 and the two permanent magnets (4, 5) are fixed on the quadrupole 6. The pickup 3 is fixed to an extension 7 that extends laterally in a cross shape of the quadrupole 6. The pickup 3 is fixed with an adhesive between the permanent magnets (4, 5), and the quadrupole 6 is also fixed with an adhesive to the printed wiring board 2. The two permanent magnets (4, 5) are arranged symmetrically with respect to the detection band of the pickup 3 near the active edge 16 of the printed wiring board 2, and the permanent magnets 4 are substantially printed. Located at the end of the wiring board 2. Permanent magnets (4, 5) form two magnetic fields of the same amplitude, but their magnetic field lines aim at two opposite directions 7 and 8, respectively, and these directions are substantially relative to the printed wiring board 2. Parallel and perpendicular to the general surface of the connector 6 and the active edge 16 of the printed wiring board.

【0012】

The detector 1 is installed to control the gasoline injection to each cylinder of the internal combustion engine 9 including the camshaft 10 in a series manner. The pulley 11 made of a soft magnetic material is protected by a cover 12 and wedged to the end of the camshaft 10. The pulley 11 has an outer rim 13 that rotates outward of the engine, and the cornered corner 14 of the rim 13 is referred to here as the target and is more than the rest of the rim 13. The thickness is significantly thicker. In this way, the pulley 11 is rotated by the camshaft 10 and can sequentially drive the piston of the first cylinder of the engine 9 in phase.

【0013】

The printed wiring board 2 of the detector 1 is attached to a shackle (connecting hardware) 15 attached to the outside of the cover 12. The printed wiring board 2 extends inward through the cover 12 and has a length or overlap substantially equal to the distance between the facing edges of the pickup 3 and the permanent magnet 4 fixed to the end of the printed wiring board. It protrudes long. The position of the active edge 16 of the printed wiring board 2 is such that the distance from the axis 17 of the camshaft 10 is slightly shorter than the inner radius of the thick portion 14 of the rim 13 of the pulley 11. Then, when this part 14 passes through the detector 1, a small gap is formed.

【0014】

When the thick portion of the rim 13 of the pulley 11, that is, the target 14, faces the detector 1, the piston in the first cylinder of the engine 9 is at top dead center. The detector 1 is installed to detect the passage of the target 14.

【0015】

We have previously confirmed that when the thin portion of the rim 13 of the pulley 11 faces the detector 1, this state is the same as the dormant state shown by the dashed line in FIG. The magnetic fields of the permanent magnets (4, 5) cancel each other out in the detection band of the pickup 3. As a result, this detection band is exposed to the resulting zero or virtually zero induced magnetic field. When the target 14 moves and passes through the permanent magnet 4 and the pickup 3, the magnetic field intersects more lines of magnetic force from the permanent magnet 4 to the hit-up 3 than lines of magnetic force from the permanent magnet 5 to the pickup 3. The reason is that the magnetic field lines of the permanent magnet 4 are superior. The result is a change in magnetic flux detected by the pickup 3, which is captured by the components of the printed wiring board 2. This change in magnetic flux produces a signal with sufficient output.

【0016】

[Effect of the invention]

The detector of the present invention has the following effects: Regardless of the size of the gap between the target and the pickup in the detector, even a slight change in magnetic flux can be detected to detect the passage of the target. -Unlike two pickups with the same characteristics, the detector is equipped with two permanent magnets with the same characteristics, so it is easy to manufacture and can perform the desired detection.

[Simple explanation of drawings]

[Figure 1]

It is a schematic diagram of the detector of this invention.

[Figure 2]

It is a partial vertical sectional view of the engine which installed the detector of this invention.

[Fig. 3]

It is the end plan view of the engine component shown in FIG.

[Explanation of symbols]

1 First cylinder detector 2 Printed circuit board 3 Unipolar Hall effect pickup 4 Permanent magnet 5 Permanent magnet 6 Quadrupole 7 Direction of magnetic field lines of permanent magnet 8 Direction of magnetic field lines of permanent magnet 9 Internal combustion engine 10 camshaft 11 pulley 12 cover 13 Pulley rim 14 Target (thick part of pulley rim) 15 shackle 16 Active edge on printed wiring board 17 Camshaft axis