JPH1182147A - Throttle opening computing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compute throttle opening while absorbing an error at the time of assembling a throttle sensor and positively make throttle opening correspond to the opening of a throttle valve. SOLUTION: When a throttle sensor 16 assembled in such a way as to be interlocked with a throttle valve 2 provided at an intake system 1 of an internal combustion engine outputs at least two output signals with different characteristics according to the opening of the throttle valve 2, throttle opening corresponding to the opening of the throttle valve 2 is computed on the basis of the output signals. The voltage value of the output signals are compared with the preset specified voltage value. In the case of the voltage value of the output signals being lower than the specified voltage value as a result of comparison, throttle opening is computed by heightening resolution regardless of an error at the time of assembling the throttle sensor 16, and in the case of the voltage value of the output signals exceeding the specified voltage value, throttle opening is computed by lowering resolution regardless of the error at the time of assembling the throttle sensor 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for calculating a throttle opening which can eliminate an error at the time of assembling the throttle valve which is generated when calculating the opening of the throttle valve.

[0002]

2. Description of the Related Art Conventionally, in an internal combustion engine such as a fuel injection system,
In order to perform control such as fuel injection control, there is one that detects an opening degree of a throttle valve. In general, the opening of the throttle valve is electrically detected using, for example, an output signal of a throttle sensor. Further, for example, there is known a device provided with a voltage correcting means for correcting an error between an actual opening degree of a throttle valve and an output signal, such as that disclosed in Japanese Patent Application Laid-Open No. 64-69737. In this example,
When the output signal of the throttle sensor is deviated from the specified value, the voltage correction resistor is replaced to correct the difference between the output signal and the specified value.

In recent years, in order to improve the accuracy of the opening in a region where the opening of the throttle valve is small, for example, as shown in FIG. Use an output signal that outputs a high voltage value for a change in the opening of the valve, and outputs an output signal of a low voltage value for a change in the opening of the throttle valve in a region where the opening of the throttle valve is high. It is known. That is, the output signal of the throttle sensor is converted into an analog-to-digital signal (A / A /
D conversion) is used as the throttle opening for determining the opening of the throttle valve in the electronic control unit. Normally, in such a throttle sensor, a break point is set at a position where the opening of the throttle valve is, for example, 30 °, and the characteristic of the voltage value of the output signal changes at the break point. Accordingly, the resolution at the time of calculation is changed in accordance with the break point, and the throttle opening is calculated so as to linearly change with respect to the opening of the throttle valve. Specifically, the resolution is, for example, 0.2 ° / LSB (minimum digit bit) in a region where the opening of the throttle valve is below the break point, and is, for example, 0.8 ° / LSB in the region above the break point.
By using such a throttle sensor, the accuracy of various controls based on the throttle opening in a region where the opening of the throttle valve is low can be increased.

[0004]

However, when a throttle sensor is mounted on a throttle body, the voltage of the output signal of the throttle sensor is normally increased depending on the state of the error at the time of mounting. The value may be different. As shown in FIG. 4, assuming that the output signal in the average assembled state is the average output signal Vm, the upper limit output signal V becomes higher than the average output signal Vm depending on the assembled state.
u or, conversely, a lower limit output signal Vl that becomes lower. In this way, when the output signal is higher or lower than the average output signal Vm, there is a break point of the average output signal Vm. When the resolution is switched based on the above, the throttle opening varies in the upper limit output signal Vu or the lower limit output signal Vl near the break point. In other words, in the case of the upper limit output signal Vu, the breakpoint is reached before the resolution is switched, and the throttle opening is calculated with the resolution before the breakpoint despite the fact that the output signal has to be switched in resolution. . As a result, only the value of the throttle opening lower than the opening of the throttle valve is calculated. In the case of the lower limit output signal Vl, the characteristics of the output signal do not change even after the resolution is switched, and the throttle opening is calculated with the resolution after the break point. Is calculated.

Therefore, due to an error in assembling the throttle sensor, the throttle opening does not become constant near the break point, and the fuel injection amount is controlled based on the throttle opening and the engine speed. In the engine,
The air-fuel ratio sometimes fluctuated in the vicinity. As a result,
Drivability may be reduced or the catalyst may be adversely affected.

An object of the present invention is to solve such a problem.

[0007]

In order to achieve the above object, the present invention takes the following measures. That is, in the throttle opening calculation method according to the present invention, the voltage value of the output signal having different characteristics output from the throttle sensor is compared with a predetermined voltage value, and the throttle opening is calculated by switching the resolution based on the comparison result. Configuration.

With such a configuration, even if an error in assembling the throttle sensor changes, the voltage value of the output signal is stable in the vicinity of the predetermined voltage value. It can be made to correspond to every time. As a result, since the throttle opening can be calculated by absorbing the error at the time of assembling the throttle sensor, the influence on the fuel injection control can be reduced, for example.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, a throttle sensor, which is mounted in conjunction with a throttle valve provided in an intake system of an internal combustion engine, outputs an output signal having at least two different characteristics in accordance with the opening of the throttle valve. A throttle opening calculating method for calculating a throttle opening corresponding to the opening of the throttle valve based on the output signal, wherein the voltage value of the output signal is compared with a predetermined voltage value set in advance, and the comparison is performed. If the voltage value of the result output signal is lower than the predetermined voltage value, the throttle opening is calculated by increasing the resolution regardless of the error in assembling the throttle sensor, and the voltage value of the result output signal is compared with the predetermined voltage value. If it exceeds, calculate the throttle opening by lowering the resolution regardless of the error when assembling the throttle sensor. There throttle opening calculation method characterized.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. An engine 100 schematically shown in FIG. 1 is for an automobile, and its intake system 1 is provided with a throttle valve 2 that opens and closes in response to an accelerator pedal (not shown), and a surge tank 3 on the downstream side thereof. Is provided.
Intake manifold 4 of intake system 1 communicating with surge tank 3
A fuel injection valve 5 is further provided near one end of the fuel injection valve 5, and the fuel injection valve 5 is controlled by an electronic control device 6. Further, an O ₂ sensor 21 for measuring the oxygen concentration in the exhaust gas is attached to the exhaust system 20 at a position upstream of a three-way catalyst 22 provided in a pipe leading to a muffler (not shown). I have. This O ₂ sensor 21
Outputs a voltage signal h corresponding to the oxygen concentration.

The electronic control unit 6 mainly includes a microcomputer system including a central processing unit 7 having a built-in A / D converter, a storage unit 8, an input interface 9, and an output interface 11. Have been. The input interface 9 has an engine speed N
A rotation speed signal b output from a cam position sensor 14 for detecting E, a vehicle speed signal c output from a vehicle speed sensor 15 for detecting vehicle speed, and a throttle sensor 16 for detecting the opening of the throttle valve 2 Throttle opening signal d which is an output signal output from the engine 10
A water temperature signal e output from a water temperature sensor 17 for detecting a cooling water temperature of 0, a voltage signal h output from the O ₂ sensor 21 and the like are input. On the other hand, the output interface 11 outputs a fuel injection signal f to the fuel injection valve 5 and an ignition pulse g to the spark plug 18.

As shown in FIG. 3, the throttle sensor 16 outputs an output signal having different characteristics, that is, a throttle opening signal, with a break point P (68% of the voltage value of the throttle opening signal d) at about 3.4 V, for example. d. That is, when the throttle sensor 16 is assembled at a standard position of a throttle body (not shown), the opening of the throttle valve 2 reaches the break point P at an angle of, for example, about 30 °, and the voltage value of the throttle opening signal d becomes About 3.4
V, and thereafter, the opening of the throttle valve 2 is about 100 °, and the voltage value of the output signal is about 5V. Specifically, when the standard throttle sensor 16 is assembled, when the opening of the throttle valve 2 is 0 °, the throttle opening signal d has an output of 10%, and the opening of the throttle valve 2 is broken at about 30 °. The point P is reached. Throttle valve 2 of throttle opening signal d up to break point P
Is steeper than the break point P. Also, due to an error during assembly, the voltage value of the throttle opening signal d when the opening of the throttle valve 2 is 0 ° is, for example, about 20% at the upper limit and about 5% at the lower limit when 5V is 100%. (FIG. 3). This is because when the throttle sensor 16 is assembled, the throttle opening signal d in the standard assembly is used.
Is caused by the parallel movement with respect to the opening degree of the throttle valve 2.

The electronic control unit 6 includes a throttle sensor 1
6 and the cam position sensor 14 calculated based on the throttle opening signal d output from
The basic injection time TP is determined using the rotation speed signal b output from the main unit as the main information, and in the steady state, the basic injection time TP is corrected by feedback control based on the voltage signal h from the O ₂ sensor 21 and is effective. The injection time TAU is determined, and the fuel is programmed to be injected in synchronization with the ignition timing based on the determined effective injection time TAU. Further, the throttle opening T for the electronic control unit 6 to determine.
In order to calculate the AM, a throttle sensor 16 that is assembled in conjunction with the throttle valve 2 provided in the intake system 1 outputs a throttle opening signal d having at least two different characteristics according to the opening of the throttle valve 2. At this time, a throttle opening TAM corresponding to the opening of the throttle valve 2 is calculated based on the output signal, and the voltage value of the throttle opening signal d is compared with a predetermined voltage value set in advance. As a result, when the voltage value of the throttle opening signal d is lower than the predetermined voltage value, the throttle opening TAM is calculated by increasing the resolution regardless of an error in assembling the throttle sensor 16, and the throttle opening is compared. When the voltage value of the signal d is higher than the predetermined voltage value, regardless of an error in assembling the throttle sensor 16, Throttle opening TA to lower the resolution
A program for calculating M is included.

The outline of the program for calculating the throttle opening TAM is as shown in FIG. In calculating the throttle opening TAM, the central processing unit 7 calculates a throttle fully closed sensor AD value T from a throttle opening signal d when the throttle valve 2 is fully closed.
AMIN2 is calculated. This is due to an error that is a deviation from a standard or average mounting position when the throttle sensor 16 is mounted, and the throttle opening TA
This is because the voltage value of the throttle opening signal d is different when M is 0, that is, when the throttle valve 2 is fully closed. By correcting this offset amount in the calculation described below, an accurate throttle opening TAM can be calculated.

In step S1, the throttle sensor 16
Is compared with a predetermined voltage value, for example, 3.4 V, to determine whether or not the voltage value is less than the predetermined voltage value. If the voltage is below or below the specified voltage value,
Move to step S2. In step S2, the throttle opening TAM is set to A / D of the voltage value of the throttle opening signal d.
Based on the conversion value ADTHROT, calculation is performed by the following equation (1). TAM = (ADTHROT-TAMIN2) * 0.2027 / 0.4 (1) That is, for one bit of a value obtained by subtracting the sensor output AD value TAMIN2 when the throttle is fully closed from the A / D conversion value ADTHROT, 0.2027 / 0 By multiplying by .4 °, the throttle opening TAM is calculated with high resolution. By this calculation, the throttle opening TAM in the section up to the break point P is obtained.

On the other hand, if the voltage value of the throttle opening signal d is equal to or higher than the predetermined voltage value in step S1, the process proceeds to step S3, and the throttle opening TA is calculated by the following equation (2).
Calculate M. TAM = (ADTHROT-TAMIN2) * 0.2027 / 0.4 + (ADTHROT- $ AE (3.4V)) * 0.8536 / 0.4 (2) That is, in the first term of the equation (2), the throttle valve up to the break point P is obtained. The throttle opening TAM corresponding to the opening of 2 is calculated, and in the second term, the voltage value from the actual A / D conversion value ADTHROT to the break point P is subtracted,
By multiplying the value of the subtraction result by 0.8536 / 0.4, the throttle opening degree T in the section after the break point P is obtained.
AM is calculated with low resolution. Therefore, the break point P
The throttle opening TAM after the break point P can be calculated in the same manner as the throttle opening TAM up to.

FIG. 3 will be described based on the case where the throttle opening signal d becomes the upper limit output signal Vu or the lower limit output signal Vl due to an assembly error of the throttle sensor 16 in the above-described configuration as in the conventional case. The upper limit output signal Vu has a higher value at the same opening of the throttle valve 2 than the throttle opening signal d in the standard assembly. Conversely, the lower limit output signal Vl has a lower value at the same opening of the throttle valve 2 than the throttle opening signal d in the standard assembly.

First, in an assembly that outputs the upper limit output signal Vu, the voltage value of the throttle opening signal d reaches the break point P before the opening of the throttle valve 2 reaches 30 °. Therefore, steps S1 → S2 are executed until the voltage value of the throttle opening signal d, that is, the A / D conversion value ADTHROT reaches 3.4V, and the throttle opening T
Calculate AM. The calculated throttle opening TAM is
The angle has not reached 30 °, and coincides with the actual opening of the throttle valve 2. Thereafter, when the A / D conversion value ADTHROT exceeds 3.4 V, steps S1 → S3 are repeatedly executed, and the throttle opening TAM is calculated by changing the resolution from the calculation up to that time. That is, the throttle opening TAM
Before the angle reaches 30 °, the throttle opening TAM is calculated by changing the resolution from before, so that the throttle opening TAM does not deviate from the opening of the throttle valve 2. Therefore, the calculated throttle opening TAM also matches the opening of the throttle valve 2 corresponding to the break point P and thereafter.

Similarly, in an assembly in which the lower limit output signal Vl is output, even when the opening of the throttle valve 2 reaches 30 °, it does not reach the break point P. Therefore, steps S1 → S2 are executed, and the throttle opening TAM is calculated by equation (1). After that, when the voltage value of the throttle opening signal d exceeds 3.4 V after the opening of the throttle valve 2 exceeds 30 °, steps S1 → S
Step 3 is repeated. As a result, the throttle opening TA
M is equal to the actual opening of the throttle valve 2 even when the opening of the throttle valve 2 is around 30 °.

As described above, even if the error at the time of assembling the throttle sensor 16 changes, the voltage value of the throttle opening signal d is stable around a predetermined voltage value. Can surely correspond to the opening degree. As a result, it is possible to calculate the throttle opening degree TAM by absorbing an error when the throttle sensor 16 is assembled.
The deviation between the calculated value and the required value when calculating P can be reduced. Therefore, the drivability can be prevented from lowering, and the combustion can be stabilized, so that the durability of the three-way catalyst 22 can be prevented from lowering.

The present invention is not limited to the embodiment described above. The constants described in the equations (1) and (2) are merely examples, and may be set according to the characteristics of the throttle sensor 16 to be used. In addition, the configuration of each unit is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

[0022]

As described above, according to the present invention, the voltage value of the output signal of the throttle sensor is stable in the vicinity of the predetermined voltage value even if the error in assembling the throttle sensor changes for each internal combustion engine. Therefore, the throttle opening can be surely made to correspond to the opening of the throttle valve regardless of the presence or absence of an error. Further, since the throttle opening can be calculated by absorbing the error at the time of assembling the throttle sensor, when the throttle opening is used for the control of the internal combustion engine, it is possible to prevent the disturbance of the control due to the variation of the throttle opening. Can be. Therefore, it is possible to prevent drivability from being reduced, and
Since the combustion can be stabilized, it is possible to prevent the durability of the catalyst from being reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration explanatory view showing one embodiment of the present invention.

FIG. 2 is a flowchart showing a control procedure of the embodiment.

FIG. 3 is an operation explanatory view of the embodiment.

FIG. 4 is an operation explanatory view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Intake system 2 ... Throttle valve 3 ... Bypass passage 4 ... Flow control valve 6 ... Electronic control unit 7 ... Central processing unit 8 ... Storage device 9 ... Input interface 11 ... Output interface 16 ... Throttle sensor

Claims (1)

[Claims] An output signal having at least two different characteristics according to an opening degree of a throttle valve is output from a throttle sensor which is mounted in conjunction with a throttle valve provided in an intake system of an internal combustion engine. A throttle opening calculation method for calculating a throttle opening corresponding to an opening of a throttle valve based on a voltage value of an output signal as a result of comparing a voltage value of an output signal with a predetermined voltage value set in advance. If the voltage is lower than the predetermined voltage value, the throttle opening is calculated with a higher resolution regardless of the error when assembling the throttle sensor.If the voltage value of the output signal exceeds the predetermined voltage value as a result of the comparison, The throttle opening is calculated by lowering the resolution regardless of an error in assembling the throttle sensor. Torr position calculation method.