JP3298173B2 - Throttle opening detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle opening detecting apparatus using a throttle position sensor comprising a plurality of magneto-electric conversion elements and magnets.

[0002]

2. Description of the Related Art Conventionally, as one type of fuel injection device for an engine, there has been known a device which obtains an intake air amount from a throttle opening and an engine speed, and controls the fuel injection amount accordingly. . As a device for detecting the throttle opening, for example, in JP-A-63-71552 and JP-T-62-500876, the throttle opening is detected by a throttle position sensor comprising two contact-type potentiometers. I have. According to this, for detection of the throttle opening, one potentiometer having a low opening and a high resolution is used according to the request of idle speed control (ISC), and the other has an appropriate resolution over the entire area. As in the case of using a throttle, it is used by appropriately switching according to the throttle opening.

[0003]

However, the above throttle opening detection device is based on the idea that high resolution is required on the low opening side.
It is unsuitable for systems requiring high resolution not only on the low opening side but also in the full opening range, such as control of the throttle position by linkless throttle control in recent years and improvement of fuel efficiency in the entire operation range.

On the other hand, in recent years, a non-contact type sensor using a magnetoelectric conversion element typified by a Hall element or a magnetoresistive element has been considered promising in place of a contact type brush type sensor due to advantages such as durability. Normally, in a throttle position sensor using a magneto-electric conversion element, a magnet is provided at one end of a rotation shaft of the throttle body so as to be rotatable together with the throttle body, and the magneto-electric conversion element detects a change in the direction of a magnetic field due to the rotation of the magnet. Therefore, the output characteristic appears as a non-linear waveform such as a sine wave. However, since the output characteristics are non-linear, there is a problem that a high-resolution part and a low-resolution part are present, and it cannot be easily applied to the above needs. A magnetoresistive element, which is one of the magnetoelectric elements, is disclosed in, for example, Japanese Patent Publication No. 3-58446.

[0005] In order to solve the above-mentioned problems, it is an object of the present invention to detect a throttle opening with high resolution over a full throttle opening range using a non-contact type sensor. .

[0006]

In order to solve the above-mentioned problems, a throttle opening detecting device according to the present invention, as illustrated in FIG. 7, has two magneto-electric conversion elements and a magnetic element disposed on a circular rotor. And the two magneto-electric conversion elements are such that the direction of the magnetic field received from the magnet is different for each magneto-electric conversion element.
In addition, one of the magnetoelectric conversion elements responds to the magnetic field generated by the magnet.
There is an offset between the magneto-sensitive surface and the magneto-sensitive surface of the other magnetoelectric transducer.
It is disposed at a position forming the bets angle, the magnetic field direction 及 each magnetoelectric transducer is received from the magnet with a change of the throttle opening
And the strength of the throttle position sensor output a non-linear detection signal from each magneto-electric conversion element. As a detection signal for a certain throttle opening, the throttle signal is selected from the respective detection signals of each magneto-electric conversion element. Throttle opening detection means for selecting a detection signal of a specific magneto-electric conversion element in accordance with an area where the rate of change of the detection signal with respect to the change of the opening is large, and detecting the throttle opening based on the detection signal. The gist is that

[0007]

In the throttle opening detecting device having the above-mentioned structure, the two magneto-electric conversion elements of the throttle position sensor are adapted to respond to the magnetic field formed by the magnet such that the direction of the magnetic field received from the magnet differs for each magneto-electric conversion element . One magnet
Between the magneto-sensitive surface of the electro-magnetic transducer and the magneto-sensitive surface of the other magneto-electric transducer.
The gap is arranged at a position forming an offset angle. That
Therefore, each magneto-electric conversion element magnetically changes as the throttle opening changes.
The direction and strength of the magnetic field from the stone changes,
The detection elements are output nonlinearly from the switching elements. Yo
Therefore, the region where the ratio of the change of the detection signal to the change of the throttle opening of each magnetoelectric conversion element is large (hereinafter referred to as
The “high-resolution region” is different for each magnetoelectric conversion element. Therefore, by switching the magneto-electric conversion elements according to the change in the throttle opening, a wide range can be set as a high-resolution area.

As a result, it is possible to detect the throttle opening with high resolution over the full throttle opening range.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram in which the present invention is applied to a system for adjusting an intake air amount to an engine by an ECU (Electronic Control Unit). A throttle valve 5 and an air flow meter 7 are provided in an intake passage 3 communicating with an intake valve 1a of the engine 1. A throttle position sensor 9 for detecting the position of the throttle valve 5 is a non-throttle sensor using two Hall elements 11a and 11b. Designed as a contact type.

The ECU 13 comprises an A / D converter 15, an input circuit 17, an output circuit 19, and a microcomputer 21. The microcomputer 21 includes a well-known CPU, ROM, and R
Various control programs are stored in the ROM with the configuration centered on the AM. The engine speed is input to the input circuit 17 by a crank angle sensor 23 connected to the crankshaft of the engine 1. A detection signal (described later) of each of the hall elements 11a and 11b is obtained from the throttle position sensor 9, an accelerator position signal is obtained from an accelerator pedal sensor 25 mounted on the accelerator pedal, an intake air amount signal is obtained from the air flow meter 7, and a battery 27 is output from the battery 27. A battery voltage signal and an intake air temperature signal from an intake air temperature sensor 29 are input to the microcomputer 21 via the A / D converter 15, respectively. The throttle control motor 31 is driven via the output circuit 19 by performing arithmetic processing on the data input to the microcomputer 21 based on a throttle control processing program described later. As a result, the throttle valve 5 is controlled to have an optimal opening according to the depression amount of the accelerator pedal and the like.

The throttle position sensor 9 of this embodiment
Is mainly composed of permanent magnets 33a and 33b and two Hall elements 11a and 11b. FIG. 2 is an explanatory view showing the positional relationship between the permanent magnets 33a and 33b and the two Hall elements 11a and 11b. FIG.
(B) is a right side view. The N pole 33a and the S pole 33b of the permanent magnet are disposed on the rotor 35 so as to be symmetrical with respect to the rotation center 5a of the throttle valve 5. The rotor 35 is provided with a rotary shaft 5 of the throttle valve 5.
b, and rotates with the rotation of the throttle valve 5.

The two Hall elements 11a and 11b are located on the axis 5c of the rotary shaft 5b of the throttle valve 5,
The rotary shaft 5b is fixed to a bearing side (not shown). When the throttle valve 5 is in the fully closed position (see FIG.
(B)), the magneto-sensitive surface of one Hall element 11a is fixed so as to be parallel to the magnetic field formed by the permanent magnets 33a and 33b, and the magneto-sensitive surface of the other Hall element 11b is fixed to the permanent magnet. Rotation direction of the throttle valve 5 with respect to the magnetic field formed by 33a and 33b (the direction of the arrow in FIG. 2B)
At an offset angle α.

In the throttle position sensor 9 configured as described above, the permanent magnets 33a and 33b are turned by the Hall element 11 with the rotation of the rotary shaft 5b of the throttle valve 5.
a and 11b, the Hall elements 11a,
The direction of the magnetic field with respect to the magneto-sensitive surface 11b changes. As a result, assuming that the incident angle of the magnetic field on the magneto-sensitive surface of the Hall element 11a is θ, the outputs VHa and VHb from the Hall elements 11a and 11b change as in the following equations (1) and (2). VHa = VA · sin θ (1) VHb = VA · sin (θ−α) (2) In the above equation, VA is an output maximum value depending on magnetic flux, element current, Hall coefficient, and the like. Thus, each output characteristic is expressed as a sine wave.

A Hall element 1 having such output characteristics
Outputs VHa and VHb of 1a and 11b are obtained by a sensor circuit 37 composed of a circuit pattern formed on a printed circuit board and a circuit element mounted on the printed circuit board, using the following equation (3).
And (4) are extracted as detection signals V1 and V2 (FIG. 3A). V1 = K · sin θ + VM1 (3) V2 = K · sin (θ−α) + VM2 (4) In the above equation, K is a constant corresponding to the amplification characteristic of the sensor circuit, and VM1 and VM2 are offset voltages. It is to be noted that the offset angle α is such that the high resolution areas of the detection signals V1 and V2 are complementary to each other over the entire throttle opening (0 to 0).
90 °).

Next, the throttle drive control process stored in the ROM of the microcomputer 21 in the ECU 13 will be described with reference to FIG. When the throttle drive control process is started, it is determined whether or not the accelerator pedal position has been input by the accelerator pedal sensor 25 (S10).
1). If not, the process returns to S101. If it is input, the throttle opening at the position of the accelerator pedal is determined as the basic throttle opening (S10).
2).

Subsequently, it is determined whether or not various corrections need to be performed on the basic throttle opening (S103). If not, the basic throttle opening is adopted as the target throttle opening (S107). . If necessary, acceleration / deceleration correction (S104), ISC correction (S105), and cruise control correction (S106) are performed, and the corrected basic throttle opening is adopted as the target throttle opening (S107).

Next, the current throttle opening is input (S1).
08), it is determined whether there is a difference between the target throttle opening and the current throttle opening (S109). If there is no difference, the holding amount of the throttle control motor 31 is determined (S11
0) If there is a difference, the drive amount of the throttle control motor 31 is determined (S111). Finally, a motor drive signal is output to drive the throttle control motor 31 and the process ends (S112).

Thus, the throttle valve 5
The opening is controlled so as to be optimal according to the amount of depression of the accelerator pedal. One of the features of the present invention is that, in the throttle opening detection process (S108: see FIG. 4), one of the detection signals is adopted according to the high resolution area of the two Hall elements 11a and 11b. It is to calculate the throttle opening. Hereinafter, the throttle opening detection process will be described with reference to FIG.

When the throttle opening detection process is started,
First, based on the detection signals V1 and V2 of the Hall elements 11a and 11b, the tables TA1 and TA2 stored in the ROM in advance.
2 to calculate the throttle openings T1 and T2 (S20).
1). The tables TA1 and TA2 are obtained by, for example,
It is created based on (3) and (4).

Next, the absolute value T12 of the difference between the throttle opening T1 and the throttle opening T2 is determined (S202). Subsequently, the absolute value T12 is compared with a permissible value KT obtained by adding a fluctuation error to a numerical value obtained by the offset angle α of the Hall element 11b (S203). If the absolute value T12 is equal to or larger than the allowable value KT ("N" in S203), a fail-safe process described later is executed. If it is less than the allowable value KT ("Y" in S203), the two Hall elements 11a and 11
The determination value KTCH for switching b is compared with the throttle opening T1 (S204). The determination value KTCH is a value corresponding to an angle for selecting the detection signals of the two Hall elements 11a and 11b, and includes the offset angle α and the Hall element 11b.
It is calculated based on each of the high resolution areas a and 11b.

Then, the throttle opening T1 becomes equal to the judgment value KTC.
When it is smaller than H ("Y" in S204), the throttle opening T1 is adopted as the throttle opening control signal TVO (S205). The throttle opening T1 is equal to the determination value KTCH
In the above case (“N” in S204), the throttle opening T2 is adopted as the throttle opening control signal TVO (S204).
206).

The above processing is shown by a solid line in FIG. 3 (B). That is, the throttle opening is 0 ° or more KTC
In the range less than H, the throttle opening T1 calculated based on the detection signal V1 of the hall element 11a is employed, and in the range where the throttle opening is KTCH or more and 90 ° or less, the detection signal V2 of the hall element 11b is used. The throttle opening degree T2 calculated based on this is adopted.

After the above-described throttle opening detection processing is completed, the flow returns to the above-described throttle drive control processing, and proceeds to S109. Next, the fail-safe processing will be described with reference to FIG. S201 of the throttle opening detection process described above
"N" means the absolute value T12 of the difference between the throttle openings T1 and T2 obtained from the Hall elements 11a and 11b.
Exceeds the allowable value KT calculated by the preset offset angle α, which means that an abnormality has occurred in one or both of the Hall elements 11a and 11b. At this time, the fail-safe process is started.

First, an engine speed obtained from the crank angle sensor 23 and an intake air amount obtained from the air flow meter 7 are used based on a two-dimensional map (not shown) created from the engine speed and the intake air amount. To calculate the predicted throttle opening T3 (S301).

Next, the absolute value T13 of the difference between the throttle opening T1 and the predicted throttle opening T3 and the absolute value T23 of the difference between the throttle opening T2 and the predicted throttle opening T3 are calculated (S302). Subsequently, the preset fail determination value KF is compared with the absolute value T13 (S30).
3). This fail determination value KF is determined by the Hall elements 11a, 1
1b is a value for determining the presence or absence of the abnormality.

When the absolute value T13 is equal to or smaller than the fail determination value KF ("N" in S303), that is, when it is determined that the Hall element 11a is normal, the throttle opening control signal TVO in the full opening range of the throttle valve 5. The throttle opening degree T1 is adopted (S304).

On the other hand, the absolute value T13 is equal to the fail determination value KF.
If it is larger (“Y” in S303), that is, if it is determined that the Hall element 11a is abnormal, the failure determination value K
F is compared with the absolute value T23 (S305). And
When the absolute value T23 is equal to or smaller than the fail determination value KF (S30)
5, "N"), that is, when it is determined that the Hall element 11b is normal, the throttle opening T2 is adopted as the throttle opening control signal TVO in the full opening range of the throttle valve 5 (S306).

On the other hand, the absolute value T23 is equal to the fail determination value KF.
If larger (“Y” in S305), that is, Hall element 1
1b indicates that the throttle valve 5
The default value TKD is adopted as the throttle opening control signal TVO in the full opening range (S307). The default value TKD is a throttle opening calculated from data such as an engine speed, an intake air amount, and an intake air temperature. For example, a predicted throttle opening T3 can be used.

After completing the above fail-safe processing, the process returns to the throttle drive control and proceeds to S109. As described in detail above, according to the throttle opening detection device of the present embodiment, the following effects can be obtained. (a) Since the two Hall elements 11a and 11b have non-linear output characteristics having different phases with respect to the throttle opening, by appropriately selecting the high resolution region of the Hall elements 11a and 11b, the throttle element can be used as a throttle valve. The throttle opening can be detected with high resolution in the full opening range. (b) Since two Hall elements 11a and 11b are used,
When an abnormality occurs in only one of them, the output of either one can be adopted in the full opening range of the throttle valve, thereby enabling a complementary fail-safe function. (C) When both of the two Hall elements 11a and 11b are abnormal, the fail-safe function is further ensured by calculating the predicted throttle opening from other input data.

It is needless to say that the present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the gist of the present invention. For example, in the present embodiment, the hall elements 11a and 11b are used for the throttle position sensor 9, but a magnetoresistive element may be used.
In the case of a magnetoresistive element, since the period of the output characteristic is half that of the Hall element, the range of the high resolution region of each magnetoresistive element is narrowed. Therefore, the present invention is more effectively applied.

[0031]

As described above in detail, according to the throttle opening detecting device of the present invention, it is possible to detect the throttle opening with high resolution over the full throttle opening range by using a non-contact type sensor. It has become possible.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing the configuration of the present embodiment.

FIG. 2 is a schematic explanatory view showing a positional relationship between a permanent magnet and a Hall element in the throttle position sensor of the embodiment.

FIG. 3 is a graph showing a detection signal of a Hall element according to the present embodiment.

FIG. 4 is a flowchart of a throttle drive control process according to the embodiment.

FIG. 5 is a flowchart of a throttle opening detection process of the embodiment.

FIG. 6 is a flowchart of a fail-safe process according to the embodiment.

FIG. 7 is a block diagram illustrating the configuration of the present invention.

[Explanation of symbols] 5 ··· Throttle valve, 5b ··· Rotating shaft, 5c ···
・ Axis line, 9 ・ ・ ・ Throttle position sensor, 11
a, 11b: Hall element, 13: ECU, 21
... microcomputer, 31 ... throttle control motor, 3
3 ... permanent magnet,

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02D 9/00 F02D 45/00 G01B 7/00

Claims (1)

(57) [Claims] 1. Arranged on two magneto-electric conversion elements and a circular rotor
The two magneto-electric conversion elements are arranged such that the direction of the magnetic field received from the magnet is different for each of the magneto-electric conversion elements.
The gap between the magneto-sensitive surface of the element and the magneto-sensitive surface of the other magneto-electric conversion element is
Each of the magneto- electric conversion elements is disposed at a position forming an offset angle, and the direction and strength of the magnetic field received from the magnet change with a change in the throttle opening, and each of the magneto-electric conversion elements outputs a non-linear detection signal from each of the magneto-electric conversion elements. A position sensor, as a detection signal for a certain throttle opening, as a detection signal for each of the magneto-electric conversion elements, a specific magneto-electric conversion element corresponding to a region where the rate of change of the detection signal with respect to a change in throttle opening is large. A throttle opening detecting device for selecting a detection signal and detecting a throttle opening based on the detection signal.