JP3196219B2 - Vehicle control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle control method for electronically controlling a vehicle.

[0002]

2. Description of the Related Art In recent years, a vehicle is provided with a control unit for controlling the vehicle for electronically controlling the running of the vehicle. This control unit is operated based on information from a sensor for detecting the state of the vehicle and the state of the internal combustion engine. It controls the timing and fuel injection amount. However, the sensors used in such a vehicle control device that detect the vehicle state and the internal combustion engine state have the same detection function, but for example, due to differences in manufacturers or manufacturing errors of each element in the sensor. The output characteristics vary from sensor to sensor, that is, even if the vehicle or internal combustion engine is in the same state, the detection result differs depending on the sensor that detects this.

[0003] Therefore, since the signals from the sensors fluctuate for the above reasons, there has been a problem that the control unit cannot properly control the vehicle.
In order to solve such a problem, a method has been devised in which the control unit recognizes the variation in the sensor output and standardizes the control unit so that control according to the output characteristics of each sensor can be performed (for example, JP-B-2-27166).

In this method, as shown in FIG. 12, a two-dimensional map is created for two control conditions (for example, a difference between sensor outputs and a difference between manufacturers), and a voltage corresponding to each control condition is generated. Select an adapter (resistor) and connect it to the external terminal of the control unit. As shown in FIG. 12, since this adapter outputs a different voltage corresponding to each characteristic of the control condition, by detecting the voltage obtained from this adapter, the control unit can recognize the output characteristic of this sensor, The control unit can execute vehicle control according to the output characteristics of each sensor.

[0005]

As described above, when selecting an adapter that emits a voltage corresponding to each control condition using a two-dimensional map in order to define two control conditions, as shown in FIG. Since each control condition has three elements, the necessary adapters are nine types.

However, if the number of elements of each control condition is three or more, the number of adapters to be prepared increases, which not only causes a problem that operation efficiency is deteriorated, but also requires a large number of adapters to be prepared. The cost must be increased. Further, when the number of control conditions becomes three, a three-dimensional map must be created, which causes a problem that the selection of an adapter becomes complicated.

Therefore, the present invention has been made to solve the above-mentioned problems, and by combining the elements of each control condition in advance, even if the number of elements of each control condition and the number of control conditions themselves become large. It is an object of the present invention to reduce the number of adapters corresponding thereto, thereby promoting cost and work efficiency reduction.

[0008]

To achieve the above object, a vehicle control method according to the present invention comprises a control unit.
A product whose output signal is inputted to, and a adapter that outputs an electric signal corresponding to at least two different products, in the control unit, the output variation that indicates the nature of each product on the basis of an output of said adapter And a vehicle control method for controlling the vehicle by selecting a predetermined combination of predetermined output variations among the different products , and setting the adapter according to the predetermined combination.

[0009]

According to the present invention, each output of at least two products is provided.
Force variations are combined in advance, and an adapter corresponding to the combination is set. The control unit detects the output signal of this adapter, and each product corresponding to the detection result
The vehicle control is executed based on the output variation indicating the characteristic of the vehicle.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. FIG. 1 is a diagram showing a structure of an oxygen sensor, for example, which is disposed in an exhaust manifold of an internal combustion engine and detects an air-fuel ratio of the internal combustion engine from an oxygen concentration in exhaust gas. In FIG. 1, reference numeral 1 denotes an element portion formed in a test tube using zirconia (ZrO ₂ ), and platinum electrodes 1a are provided on both surfaces thereof.
Further, the outside of the electrode is covered with a ceramic layer 2 to protect the electrode, and an atmosphere having a high oxygen concentration is introduced into the inside 3 and an exhaust gas having a low oxygen concentration is introduced into the outside 4. With such a configuration, as shown in FIG. 2, when the air-fuel ratio switches from a rich (rich) side to a thin (lean) side at the stoichiometric air-fuel ratio, the electromotive force changes greatly.

Therefore, it is possible to know whether the air-fuel ratio is in a rich state or a lean state by detecting the voltage of the voltmeter 5 using this characteristic. Note that the above-described detection unit for determining the air-fuel ratio of the internal combustion engine is hereinafter referred to as a sensor unit. 6
Is a ceramic heater (hereinafter, referred to as a heater unit) provided to keep the oxygen sensor temperature at a high temperature because the characteristics shown in FIG. 2 appear only under relatively high temperature conditions. And a protective cover for protecting the heater section.

However, in the above-described apparatus, the output value of the detection signal from the sensor unit varies due to, for example, a difference in the thickness of the ceramic layer 2 covered or a difference in the pore density of the ceramic layer 2. Also, in the heater section, variations in heater resistance occur due to slight differences in conditions during the production of ceramics. When such a variation occurs, for example, when it is desired to control the heater temperature to a predetermined temperature,
Even if the same voltage is applied as shown in FIG. 3, the actual temperature differs (temperature T ₁ and temperature T ₂ ) due to variation in heater resistance, so that accurate temperature control cannot be performed.

[0013] Similarly, since the output of the sensor unit also varies for each sensor for the reasons described above, as shown in FIG. 4, different values of the air-fuel ratio value of the supply current I _S is detected even in the same, It is difficult to accurately detect the air-fuel ratio,
Optimal vehicle control is not possible. FIG. 5 is a schematic configuration diagram of an air-fuel ratio control device using the above-described oxygen sensor.

In FIG. 5, reference numeral 11 denotes the above-described oxygen sensor, the tip of which is inserted into the exhaust pipe 10. Further, the sensor signal 11a and the heater signal 11 are output from the oxygen sensor.
b is output and input to the A / D converter 16 in the control unit 15 described later via the connector 12 and the connector 14. Reference numeral 13 denotes a variation in output between the sensor unit signal 11a and the heater unit signal 11b,
A resistor (adapter) selected by a method described later and connected to the inside of the connector 12.

Reference numeral 15 determines a control amount for controlling the vehicle, such as an ignition timing and a fuel injection amount of the internal combustion engine, based on information from the oxygen sensor 11 and sensors (not shown) such as a throttle sensor and a crank angle sensor. This is a microcomputer having an A / D converter 16, a central processing unit (CPU) 17, and a storage device (ROM) 18.

The CP in the control unit 15
U17 detects an output V obtained by A / D-converting an output 13a from a resistor 13 provided outside the control unit 15, and detects a sensor unit and a heater unit which form two control conditions of the oxygen sensor 11 according to the output V. A correction coefficient for compensating for the variation in is selected from the ROM 18. Then, an operation for compensating the variation by taking this correction coefficient into account and performing accurate vehicle control is executed. One end of the resistor 13 is connected to a power source + B via a connector 14.

In this manner, by selecting one resistor 13 for the output having two variations in the output of the sensor section signal 11a and the heater section signal 11b, the control unit 15 controls the sensor section and the heater section. Accurate vehicle control according to characteristics can be performed. Next, a method for selecting the resistor 13 which is a main part of the present invention will be described in detail.

In this embodiment, the control unit 15
In the above, a correction coefficient K for compensating for variations in the output of the sensor unit of the oxygen sensor 11 and the heater resistance (set by multiplying each value by the correction coefficient K so that the variations in the product become the design target values) A specific combination of the sensor unit and the heater unit of the oxygen sensor 11 is set in advance so as to have the same value. That is, a specific combination is set such that the correction coefficient K _i of the sensor unit is equal to the correction coefficient K _{t of the} heater resistance (K = K _i = K _t ).

Therefore, as shown in the following table (Table 1), when there are two control conditions (sensor output, heater resistance) and each control condition has five elements, for example, when the correction coefficient _Ki is 1 2.0 a sensor unit output of the sensor unit when the oxygen concentration of 7.5% is an output belonging to the 12.8 to 13.2 [mA] is, the temperature correction coefficient K _t is also 1.0 The value of the heater resistance at 23 ° C. is 1.18 to 1.22 [Ω]
Are combined at the time of production, and the output V of the A / D converter 16 is 2-3 in this combination.
The resistor 13 is set to be [V].

FIG. 6 is a schematic diagram of each element in Table 1. The horizontal axis indicates the output of the sensor unit when the oxygen concentration is 7.5% and the value of the heater resistance when the temperature is 23 ° C. The vertical axis indicates the output V of the A / D converter 16.

[0021]

[Table 1]

[0022] Next, the operation of the control unit 15 according to the above combination will be described with reference to the flowchart shown in FIG.

When power is supplied, an initialization process of the control unit 15 is executed in step 100, and in step 110, the voltage generated across the resistor 13 is converted into digital data by the A / D converter 16 to output V.
Read. In step 120, based on the output V from the A / D converter 16 read in step 110, correction coefficients K _i and K _t are obtained from a map as shown in FIG. The map shown in FIG. 8 is created corresponding to the table (Table 1) used when combining the above-described sensor unit and heater unit.

In step 130, the detection signal from the sensor section of the oxygen sensor 11 and the heater temperature are read. In step 140, the values read in step 130 are multiplied by the correction coefficients K _i and K _t obtained in step 120, respectively. And the heater temperature are corrected,
An arithmetic process is executed by a main routine (not shown) based on the correction value to perform optimal vehicle control.

As described above, in this embodiment, a map for obtaining the correction coefficients K _i and K _t can be shared by previously combining the correction coefficients of the output of the sensor section and the heater resistance so as to be the same. correction coefficient K _i of one map, also an effect that it is possible to determine the K _t to Kanade.
The combination of the output of the sensor unit and the heater resistance is shown in FIG.
In this case, the variation of each control condition can be corrected by rewriting the map stored in the storage device 18 as shown in FIGS.

In the present embodiment, when the combination of the sensor unit and the heater unit of the oxygen sensor 11 is set in advance, the sensor unit and the heater unit are divided into five parts in accordance with these variations, and they are combined. In particular, the number of divisions does not need to be the same. Next, the present invention will be described in more detail based on a second embodiment in which the combination conditions are changed from the above-described embodiment.

In the oxygen sensor 11 shown in the above embodiment, the output of the sensor unit at an oxygen concentration of 7.5% and the resistance of the heater at 23 ° C. were measured, and the number was determined for each of the measured values to obtain a frequency distribution. When the table is created, FIG. 9 and FIG.
As shown in FIG. Therefore, as shown in FIG. 9, the variation distribution of the output of the sensor unit is small.
The number of divisions may be reduced according to the variation distribution as shown in the following table (Table 2) to reduce the number of elements of the control condition. FIG. 11 is a diagram of Table 2 similarly to FIG.

[0028]

[Table 2]

[0029] Hereinafter, the sensor unit and the heater unit are combined based on Table 2, and the resistor 13 corresponding to the combination is set, and the resistor 13 is provided outside the control unit 15 as shown in FIG. A correction coefficient corresponding to the output of the controller 13 is selected from the ROM 18 and vehicle control is executed based on the flowchart shown in FIG. 7 in the same manner as in the first embodiment.

As described above, by dividing and combining according to the variation distribution, the combination can be set without leaving the sensor unit or the heater unit. Next, in the above embodiment, the control conditions (output of the sensor unit, heater resistance)
However, the case where the number of control conditions is two or more will be described in detail based on the third embodiment.

For example, when vehicle control is performed using two oxygen sensors 11 described above (for example, when oxygen sensors are disposed before and after a catalyst for purifying hydrocarbons and carbon monoxide in exhaust gas), Since there are two sensor outputs and two heater resistances, there are four control conditions. At this time, according to the output of the sensor unit and the value of the heater resistance, Table 1
And when divided like Table 2, it becomes as shown in Table 3,
Was i ₁ through i ₆ and r ₁ ~r ₆ for each region.

Here, as shown below, for example, the sensor A
Each element of all the control conditions, such as the output i ₁ , the sensor B output i ₄ , the heater A resistance r _1, and the heater B resistance r ₄ , may be combined, and one resistance 13 may be set according to the combination. However, the present invention is not limited to this. For example, one resistor 13 may be set by combining the sensor A output i ₁ , the sensor B output i _4, and the heater A resistance r ₁ based on a predetermined rule.
Further, one resistor 13 may be set by combining only the sensor B output i ₄ and the heater B resistance r ₄ .

[0033]

[Table 3]

[0034] In this way, at least one of the elements between different control conditions is combined, and the resistance 13 corresponding to this combination is combined.
Is set, the type of the resistor 13 required can be suppressed, and the circuit for connecting the resistor 13 can also be suppressed. Therefore, the number of A / D converters and the number of ports accompanying this can be minimized. be able to. Further, as described above, the type of the resistor 13 can be minimized by combining all elements between different control conditions.

In the present embodiment, a resistor (resistor 13) is used as a means for informing the control unit 15 of a combination of control conditions. However, the control unit 15 is controlled by using another output signal such as a coil or a transmitter. You may let me know. In the present embodiment, the resistor 13 is provided in the adapter 12 because it is advantageous in the manufacturing process. However, the present invention is not limited to this. For example, the resistor 13 may be provided around the control unit 15.

In this embodiment, the resistor 13 is provided for the purpose of correcting variations in the output of the sensor portion of the oxygen sensor 11 and the heater resistance. However, it is needless to say that other control conditions such as a vehicle type and a sensor manufacturer may be used. A resistor 13 may be provided for the purpose of correcting variations.

[0037]

As described above, in the present invention, as described above,
By combining output variations between products in advance,
Even if the number of output variations of each product and the number of products themselves increase, the number of adapters and the types of adapters can be extremely reduced, thereby improving work efficiency and reducing costs. Further, an excellent effect is obtained that the number of circuits for connecting the adapter and the number of ports of the control unit can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an oxygen sensor used in an embodiment of the present invention.

FIG. 2 is a characteristic diagram of the oxygen sensor shown in FIG.

3 is an output characteristic diagram of a heater section of the oxygen sensor shown in FIG.

4 is an output characteristic diagram of a sensor unit of the oxygen sensor shown in FIG.

FIG. 5 is a schematic configuration diagram of an air-fuel ratio control device of an embodiment.

FIG. 6 is a diagram showing a combination of a sensor unit and a heater unit.

FIG. 7 is a flowchart for explaining the operation of the control unit.

FIG. 8 is a map for obtaining a correction coefficient in a control unit.

FIG. 9 is a diagram illustrating a frequency distribution of an output of a sensor unit according to the second embodiment.

FIG. 10 is a diagram showing a frequency distribution of heater resistance in the second embodiment.

FIG. 11 is a diagram showing a combination of a sensor unit and a heater unit.

FIG. 12 is a map for selecting a conventional adapter.

FIG. 13 is a diagram showing a combination of a sensor unit and a heater unit.

FIG. 14 is a map for obtaining a correction coefficient in the control unit.

FIG. 15 is a map for obtaining a correction coefficient in the control unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Element part 2 Ceramic layer 6 Ceramic heater 11 Oxygen sensor 12 Adapter 13 Resistance 15 Control unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-53-25775 (JP, A) JP-A-3-156153 (JP, A) JP-A-58-127119 (JP, A) 31360 (JP, U) JP-A 62-14503 (JP, U) JP-A 2-144187 (JP, U) JP-A 57-41137 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) F02D 41/00-45/00 395

Claims (2)

(57) [Claims] 1. An output signal from a control unit is transmitted to a control unit.
It has a product that is input, and an adapter for outputting an electric signal corresponding to at least two different products, the controlling
In the roll unit, there is provided a vehicle control method for performing vehicle control by selecting an output variation indicating a property of each product based on an output of the adapter , wherein a predetermined value between different products is determined.
A specific combination of the output variations of the above is determined in advance, and the adapter is set according to the combination. 2. Output signals from various products are input and
Executes calculations for vehicle control based on the output signal
Comprising a control unit and a A outputs a signal corresponding to the output variation of said product in a product having the same function in the control unit <br/> adapter to the control unit, the output signal of said adapter
Correction coefficient selecting means for selecting a correction coefficient for compensating output variation of the product based on the map from a map,
Calculating means for performing an operation for performing vehicle control based on a value obtained by compensating the output of the product with the correction coefficient, wherein the map has a correction coefficient for compensating for output variations of each of the plurality of products. A vehicle control device, which is set to be equal.