JPH10299558A - Rotation detector for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform detection of a crank angle and discrimination of a cylinder by only a single sensor part. SOLUTION: Between the center of rotation of a signal rotor 12 fitted to a crankshaft 11 and a tooth lacked part 14, an auxiliary rotor 17 is rotatably mounted. In a peripheral part of this auxiliary rotor 17, a cylinder discriminating detection part 18 is formed, and a part except this part is formed as non- detection part 26. A gear mechanism 19 rotating the auxiliary rotor 17 associated with rotation of the signal rotor 12 is provided, and in a position where both a tooth part 13 of the signal rotor 12 and the cylinder discriminating detection part 18 of the auxiliary rotor 17 can be detected, a single sensor part 23 is arranged. In the gear mechanism 19, in a manner wherein through a front of the sensor part 23, a condition that the tooth lacked part 14 of the signal rotor 12 and the cylinder discriminating detection part 18 of the auxiliary rotor 17 are overlapped to pass and a condition that the tooth lacked part 14 of the signal rotor 12 and the non-detection part 26 of the auxiliary rotor 17 are overlapped to pass are made to appear alternately in each turn of the signal rotor 12, thereby gear ratio is set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation detecting device for an internal combustion engine that detects a crank angle of the internal combustion engine and determines a cylinder.

[0002]

2. Description of the Related Art A conventional general internal combustion engine is disclosed in
As shown in JP-A-206323, a crank sensor that generates a pulse signal at every predetermined crank angle according to the rotation of the crankshaft, and one rotation of the camshaft (two rotations of the crankshaft)
And a cam sensor that outputs one cylinder discrimination signal for each cylinder. Based on the cylinder discrimination signal output from the cam sensor, a pulse signal output from the crank sensor is counted to determine a crank angle, thereby performing cylinder discrimination. It has become.

[0003]

However, in the above configuration, a cam sensor is required in addition to the crank sensor, which increases the number of parts and increases the cost.
It is necessary to secure a space for mounting two sensors, and it is not possible to satisfy the demand for space saving and compactness.

Therefore, in recent years, as a method of discriminating cylinders using only a crank sensor without using a cam sensor, Japanese Patent Laid-Open No.
As described in Japanese Patent Publication No. 213052, there is an apparatus in which fuel injection of a specific cylinder is cut off and cylinder determination is performed based on the presence or absence of misfire. However, if the misfire is intentionally caused by cutting the fuel injection of the specific cylinder, there is a disadvantage that torque fluctuation occurs and drivability deteriorates.

The present invention has been made in view of such circumstances, and accordingly, it is an object of the present invention to detect a crank angle and detect a cylinder with only one sensor unit without causing a misfire for cylinder discrimination. It is an object of the present invention to provide an internal combustion engine rotation detecting device capable of performing the determination.

[0006]

In order to achieve the above object, a rotation detecting device for an internal combustion engine according to a first aspect of the present invention is provided with a predetermined pitch on an outer peripheral portion of a signal rotor rotated by a crankshaft of the internal combustion engine. To form a plurality of crank angle detecting portions, and a non-detecting portion having no crank angle detecting portion is formed in a part of the outer peripheral portion. An auxiliary rotor is rotatably mounted between the rotation center of the signal rotor and the non-detecting portion, and a cylinder discriminating detecting portion is formed at a predetermined position on the outer peripheral portion of the auxiliary rotor, and the other outer peripheral portions are not detected. Department.
A gear mechanism for rotating the auxiliary rotor mechanically in association with the rotation of the signal rotor is provided, and one sensor is provided at a position where both the crank angle detection unit of the signal rotor and the cylinder discrimination detection unit of the auxiliary rotor can be detected. Place the part. In the gear mechanism, a state where the non-detection portion of the signal rotor and the detection portion for cylinder discrimination of the auxiliary rotor pass in front of the sensor portion overlaps with the non-detection portion of the signal rotor and the non-detection portion of the auxiliary rotor. The gear ratio is set so that the state of passing through the signal rotor alternates with each rotation of the signal rotor.

[0007] Thus, for every two rotations of the signal rotor (two rotations of the crankshaft), one non-detection portion of the signal rotor (or a cylinder discriminating detection portion of the auxiliary rotor).
Is detected by the sensor section, and the cylinder can be determined based on this. In addition, the sensor unit can detect the crank angle by detecting the crank angle detection unit of the signal rotor. Therefore, according to the present invention, it is possible to detect the crank angle and determine the cylinder with only one sensor unit without causing a misfire for the cylinder determination. Can be satisfied, and the problem of reduced drivability due to misfire can be avoided.

In this case, the gear ratio of the gear mechanism is set so that the auxiliary rotor makes an odd number of rotations while the signal rotor makes two rotations. The sensor unit detects the state where the cylinder discriminating detection unit of the auxiliary rotor is located at the center of the non-detection unit of the signal rotor every time the signal rotor makes two rotations. You may do it. With this configuration, it is possible to reliably determine the cylinder discriminating detection section of the auxiliary rotor and the non-detection section of the signal rotor from the output signal of the sensor section.

Further, the crank angle detecting section of the signal rotor and the cylinder discriminating detecting section of the auxiliary rotor are formed of a magnetic material, and a magnetic field detecting means to which a bias magnetic field is applied by a magnet is used as a sensor section. May be used. Here, examples of the magnetic detection means include a magnetic sensor such as a Hall element and a magnetoresistive element and an electromagnetic pickup, which can accurately detect a crank angle detecting section and a cylinder discriminating detecting section.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. A signal rotor 12 made of an iron-based magnetic material is fitted to a crankshaft 11 of an internal combustion engine (not shown) by press fitting or the like. The outer peripheral portion of the signal rotor 12 has a tooth portion 1 serving as a crank angle detecting portion.
3 (protrusions) are formed at a pitch of, for example, 10 ° C., and
A toothless portion 14 (non-detection portion) having no tooth portion 13 is formed in a part of the outer peripheral portion. In this case, the missing tooth portion 14
The length of the pitch of the tooth portion 13 is three pitches or more (that is, the tooth portion 1
3 is missing).

A shaft pin 15 is fixed to the signal rotor 12 between the crankshaft 11 and the toothless portion 14 by press-fitting or the like, and an auxiliary rotor 17 is rotated on the shaft pin 15 via a bearing 16. Mounted as possible. The auxiliary rotor 17 is also made of an iron-based magnetic material, like the signal rotor 12, and has a cylinder-detection detecting portion 18 formed at one position on the outer peripheral portion thereof, and the other portion has a non-detecting portion 26. It has become.

In this case, the shaft pin 15 of the auxiliary rotor 17
Is located on a straight line connecting the crankshaft 11 and the center of the toothless portion 14. As shown in FIG. 1, when the cylinder discriminating detection unit 18 of the auxiliary rotor 17 rotates to the uppermost position, the cylinder discriminating The upper end of the detector 18 projects from the center of the toothless portion 14 of the signal rotor 12 by the height of the tooth 13.

On the other hand, a gear mechanism 19 for rotating the auxiliary rotor 17 mechanically in conjunction with the rotation of the signal rotor 12.
Is composed of an annular sun gear 21 mounted and fixed concentrically to the crankshaft 11 via an attachment member 20 to an engine block (not shown), and a planetary gear 22 integrally formed on the side surface of the auxiliary rotor 17. It has a configuration of meshing. The ratio of the number of teeth between the sun gear 21 and the planetary gear 22 is, for example, 3:
The auxiliary rotor 17 (planetary gear 22) rotates 1.5 times around the shaft pin 15 while the signal rotor 12 makes one rotation and the planetary gear 22 makes one round around the sun gear 21. (That is, the signal rotor 12
The auxiliary rotor 17 makes three rotations during the two rotations of.

On the other hand, a sensor section 23 is provided at a position where both the tooth section 13 of the signal rotor 12 and the cylinder discriminating detecting section 18 of the auxiliary rotor 17 can be detected. In the sensor section 23, a magnetic sensor 24 such as a Hall element or a magnetoresistive element, which is a magnetic detecting means, and a magnet 25 for applying a bias magnetic field to the magnetic sensor 24 from the rear side are incorporated.

The operation of the rotation detecting device configured as described above will be described. When the signal rotor 12 is rotated by the rotation of the crankshaft 11, the planetary gear 22 of the auxiliary rotor 17 orbits around the sun gear 21 integrally with the signal rotor 12, and accordingly, the auxiliary rotor 17 (the planetary gear 2) is rotated.
2) rotates around the shaft pin 15. In this embodiment,
The gear ratio of the gear mechanism 19 is such that while the signal rotor 12 makes one rotation and the planetary gear 22 makes one round around the sun gear 21, the auxiliary rotor 17 (the planetary gear 22) rotates about the shaft pin 15. Since it is set to rotate five times, the toothless portion 14 of the signal rotor 12 and the cylinder discriminating detection unit 18 of the auxiliary rotor 17 pass in front of (below in the drawing) the sensor unit 23. 1 (a state in FIG. 1) and a state in which the toothless portion 14 of the signal rotor 12 and the non-detection portion 26 of the auxiliary rotor 17 pass through (the state in FIG. 3) alternately for each rotation of the signal rotor 12. Appears in FIG.
2 shows a state in which the signal rotor 12 (crankshaft 11) has rotated by 180 ° C. from the state shown in FIG.
When the motor is further rotated by 180 ° C. from the state shown in FIG. 3, the state shown in FIG. 3 is obtained.

While the signal rotor 12 is rotating, as shown in FIG. 2, every time the teeth 13 of the magnetic material approach the sensor 23, the magnetic flux emitted from the magnet 25 of the sensor 23
, The density of the magnetic flux passing through the magnetic sensor 24 increases, the output of the magnetic sensor 24 increases, and each time the tooth portion 13 moves away from the sensor portion 23, the magnetic sensor 2
4, the density of the magnetic flux passing therethrough decreases, and the output of the magnetic sensor 24 decreases. Thereby, during rotation of the signal rotor 12, each time the tooth portion 13 passes in front of the sensor portion 23, a pulse signal (crank angle signal) is periodically output from the magnetic sensor 24 as shown in FIG. It is taken into an engine control circuit (not shown).

As shown in FIG. 3, in front of the sensor section 23, the toothless section 14 of the signal rotor 12 and the auxiliary rotor 1
7, the magnetic flux coming out of the magnet 25 is dispersed and the density of the magnetic flux passing through the magnetic sensor 24 is reduced, and the output of the magnetic sensor 24 becomes low level. It is maintained and no pulse signal is output.

On the other hand, as shown in FIG. 1, when the toothless portion 14 of the signal rotor 12 and the cylinder discriminating detection portion 18 of the auxiliary rotor 17 pass in front of the sensor portion 23, the sensor portion 23 When the magnetic flux emitted from the magnet 25 passes through the cylinder discriminating detection unit 18, the density of the magnetic flux passing through the magnetic sensor 24 increases. As a result, when the state shown in FIG.
Outputs a pulse signal.

The engine control circuit reads the pulse signal output from the magnetic sensor 24 and counts the pulse signal. Each time the pulse signal is read, the engine control circuit compares the signal pitch with the previous signal pitch and compares the signal pitch with the previous signal pitch. It is determined whether the number is 14 or the cylinder determining detector 18. That is, as shown in FIG. 4, the signal pitch of the tooth portion 13 is T1, the signal pitch of the toothless portion 14 is T2, and the signal pitch of the cylinder discriminating detecting portion 18 is T3.
Then, there is a relationship of T1 <T3 <T2. In the present embodiment, the toothless portion 14 is
If the measured signal pitch is, for example, twice or more the signal pitch T1 of the tooth portion 13, it is determined that the tooth is missing. On the other hand, the cylinder discriminating detection unit 1
8 is about 1.5 times the signal pitch T1 of the tooth portion 13, so that the missing tooth portion 14 and the cylinder discriminating detection are determined by whether or not the signal pitch T1 of the tooth portion 13 is, for example, twice or more. The part 18 can be distinguished sufficiently.

As described above, the state in which the missing tooth portion 14 is detected (the state shown in FIG. 1) is once for every two rotations (720 ° C. A) of the signal rotor 12 (crankshaft 11). By counting the pulse signal output from the magnetic sensor 24 using the position where the unit 14 is detected as a reference position, it is possible to detect the crank angle and determine the cylinder. Accordingly, the detection of the crank angle and the cylinder discrimination can be performed by only one sensor unit 23, so that the demand for cost reduction, space saving and compactness can be satisfied, and the cylinder discrimination as in the conventional case can be performed. It is not necessary to cause a misfire, and the problem of reduced drivability due to the misfire can be avoided.

In this embodiment, the signal rotor 12
The toothless portion 14 is formed to have a length corresponding to three pitches of the tooth portion 13, but may be formed longer. In this embodiment, the gear ratio of the gear mechanism 19 is set such that the auxiliary rotor 17 makes three rotations while the signal rotor 12 makes two rotations. The rotation may be set to make one or five or more odd rotations.

Further, in the present embodiment, the magnetic sensor 24 such as a Hall element or a magnetoresistive element is used for the sensor section 23, but an electromagnetic pickup may be used. Further, in the present embodiment, the bias magnetic field is applied to the magnetic sensor 24 by the magnet 25. However, the magnet 25 is omitted, and the outer circumference of the signal rotor is multipolar magnetized at a predetermined pitch to detect a plurality of crank angles. The magnetized portion (detection portion) may be formed, and a non-detection portion (non-magnetized portion) may be formed in a part of the outer peripheral portion. In this case, a part of the outer peripheral portion of the auxiliary rotor is magnetized to form a cylinder discriminating magnetized portion (detecting portion), and the other outer peripheral portion is set as a non-detecting portion (non-magnetized portion). good.
For magnetizing the outer periphery of each rotor, a magnet may be attached to the outer periphery of each rotor.

The sensor for detecting the crank angle detecting section of the signal rotor and the cylinder discriminating detecting section of the auxiliary rotor includes:
The invention is not limited to the magnetic detection means such as the magnetic sensor 24 and the electromagnetic pickup, and the optical sensor may be used to detect the crank angle detection unit of the signal rotor and the cylinder discrimination detection unit of the auxiliary rotor.

Further, in this embodiment, the planetary gear 22 is formed integrally on the side surface of the auxiliary rotor 17, but another piece of gear may be mounted on the side surface of the auxiliary rotor.

[Brief description of the drawings]

FIGS. 1A and 1B show an embodiment of the present invention, in which FIG. 1A is a front view of a rotation detecting device, and FIG.

FIG. 2 (a) shows a state where the signal rotor is 18 from the state of FIG.
Front view of a rotation detection device showing a state of 0 ° A rotation,
(B) is a longitudinal side view of the same.

FIG. 3 (a) shows a state where the signal rotor is 18 from the state of FIG.
Front view of a rotation detection device showing a state of 0 ° A rotation,
(B) is a longitudinal side view of the same.

FIG. 4 is a waveform diagram of an output signal of a sensor unit.

[Explanation of symbols]

11 ... Crankshaft, 12 ... Signal rotor, 13 ... Tooth part (crank angle detection part), 14 ... Tooth missing part (non-detection part), 1
7 ... Auxiliary rotor, 18 ... Cylinder discriminating detection section, 19 ... Gear mechanism, 21 ... Sun gear, 22 ... Planetary gear, 23 ... Sensor section, 24 ... Magnetic sensor (magnetic detection means), 25 ... Magnet,
26: Non-detection unit.

Claims (3)

[Claims] 1. An internal combustion engine rotation detecting device for detecting a crank angle of an internal combustion engine and discriminating a cylinder, comprising: a plurality of crank angles which are rotated by a crankshaft of the internal combustion engine and formed at a predetermined pitch on an outer peripheral portion. A signal rotor having a detection portion and having a non-detection portion without a crank angle detection portion in a part of the outer peripheral portion; and a rotatable attachment between a rotation center of the signal rotor and the non-detection portion; The auxiliary rotor having a cylinder discriminating detection unit at a predetermined position, and the other outer peripheral portion being a non-detecting unit, and detecting both the crank angle detecting unit of the signal rotor and the cylinder discriminating detecting unit of the auxiliary rotor. And a gear mechanism for rotating the auxiliary rotor by mechanically interlocking with the rotation of the signal rotor, wherein the gear mechanism is provided in front of the sensor section. A state where the non-detection part of the signal rotor and the cylinder discriminating detection part of the auxiliary rotor overlap and pass, and a state where the non-detection part of the signal rotor and the non-detection part of the auxiliary rotor overlap and pass. Wherein the gear ratio is set so that the signals appear alternately every one rotation of the signal rotor. 2. The gear ratio of the gear mechanism is set such that the auxiliary rotor makes an odd number of rotations while the signal rotor makes two rotations, and the non-detection part of the signal rotor is provided with a pitch of the crank angle detection part. The sensor unit detects a state in which the cylinder discriminating detection unit of the auxiliary rotor is located at the center of the non-detection unit of the signal rotor every time the signal rotor makes two rotations. The rotation detection device for an internal combustion engine according to claim 1, wherein 3. A crank angle detecting section of the signal rotor and a cylinder discriminating detecting section of the auxiliary rotor are projections formed of a magnetic material, and the sensor section is a magnet to which a bias magnetic field is applied by a magnet. 3. The rotation detection device for an internal combustion engine according to claim 1, wherein the rotation detection device is a detection unit.