JPH04255549A - Vehicle control method - Google Patents

Abstract

PURPOSE:To reduce a cost and work efficiency by setting a kind of corresponding adaptors decreased even when an element of control condition and the control condition are increased to a large number. CONSTITUTION:Relating to two control conditions(sensor output, heater resistance) having unevenness in characteristic, each element of the two control conditions is combined based on a predetermined rule. For instance, in an oxygen sensor, a sensor part of 12.8 to 13.2mA sensor output at the time of 7.5% oxygen concentration and a heater part of 1.18 to 1.22omega heater resistance value at the time of 23 deg.C temperature are previously combined based on the predetermined rule to set an adaptor for generating 2 to 3V output voltage of a corresponding A/D converter. By detecting this generated voltage in a control unit, vehicle control in accordance with the sensor output in the oxygen sensor and unevenness provided in the heater resistance can be performed.

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

BACKGROUND OF THE INVENTION In recent years, vehicles have been equipped with vehicle control control units for electronic driving control, and these control units control, for example, ignition control based on information from sensors that detect vehicle conditions and internal combustion engine conditions. It controls timing, fuel injection amount, etc. However, even if the sensors used in such vehicle control devices to detect vehicle conditions and internal combustion engine conditions have the same detection function, they may differ due to differences in manufacturers or manufacturing errors in each element within the sensor. Output characteristics vary from sensor to sensor, that is, even if the vehicle or internal combustion engine is in the same state, the detection results differ depending on the sensor that detects it.

[0003] Therefore, since the signals from the sensors vary due to the above-mentioned reasons, there has been a problem in that the control unit cannot properly control the vehicle. In order to solve such problems, methods have already been devised to standardize the control unit so that the control unit recognizes the variations in sensor output and can perform control according to the output characteristics of each sensor (for example, , Special Publication No. 2-27166).

As shown in FIG. 12, this method creates a two-dimensional map for two control conditions (for example, differences in sensor output and differences in manufacturer), and generates a voltage corresponding to each control condition. Select an adapter (resistor) and connect it to the external terminal of the control unit. As shown in Figure 12, this adapter outputs different voltages corresponding to the characteristics of the control conditions, so by detecting the voltage obtained from this adapter, the control unit can recognize the output characteristics of this sensor. The control unit can perform vehicle control according to the output characteristics of each sensor.

[0005]

[Problems to be Solved by the Invention] As mentioned above, when selecting an adapter that emits voltage corresponding to each control condition using a two-dimensional map to define two control conditions, in FIG. Since each control condition has three elements, nine types of adapters are required.

However, when the number of elements for each control condition increases to three or more, the number of types of adapters that must be prepared increases, which not only causes problems such as decreased work efficiency, but also requires the preparation of a large number of adapters. This leads to an increase in costs. Furthermore, when there are three control conditions, a three-dimensional map must be created, which causes the problem of complicating adapter selection.

The present invention has been made to solve the above problems, and by combining the elements of each control condition in advance, even if the number of elements of each control condition and the control conditions themselves become large, , the number of corresponding adapters can be reduced, and the purpose is to promote reductions in cost and work efficiency.

[0008]

[Means for Solving the Problems] In order to achieve the above object, a vehicle control method according to the present invention includes an adapter that outputs electrical signals corresponding to at least two different control conditions, and based on the output of the adapter, A vehicle control method for controlling a vehicle by selecting control elements indicating properties of each control condition, wherein a specific combination of control elements between different control conditions is determined in advance, and the adapter is set according to this combination. Adopt technical means.

[0009]

According to the present invention, each element of at least two control conditions is combined in advance, and an adapter corresponding to the combination is set. The output signal of this adapter is detected, and vehicle control is executed based on control elements indicating the nature of each control condition corresponding to the detection result.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on embodiments shown in the drawings. FIG. 1 is a diagram showing the structure of an oxygen sensor that is disposed, for example, in an exhaust manifold of an internal combustion engine and detects the air-fuel ratio of the internal combustion engine from the oxygen concentration in exhaust gas. In FIG. 1, reference numeral 1 denotes an element section formed in the shape of a test tube using zirconia (ZrO2), with platinum electrodes 1a provided on both sides, and a ceramic layer 2 on the outside of the electrode to protect the electrodes.
The inside 3 is covered with atmospheric air with a high oxygen concentration, and the outside 4 is introduced with exhaust gas with a low oxygen concentration. With this configuration, as shown in FIG. 2, when the air-fuel ratio switches from the rich side to the lean side with the stoichiometric air-fuel ratio as a boundary, the electromotive force changes significantly.

[0011] By utilizing this characteristic and detecting the voltage of the voltmeter 5, it is possible to know whether the air-fuel ratio is in a rich state or a lean state. Note that the detection section for determining the air-fuel ratio of the internal combustion engine described above is hereinafter referred to as a sensor section. 6
is a ceramic heater (hereinafter referred to as the heater section) provided to keep the oxygen sensor temperature at a high temperature since the characteristics shown in Fig. 2 appear only under relatively high temperature conditions, and 7 is the sensor section. and a protective cover for protecting the heater section.

However, in the above device, the output value of the detection signal from the sensor section varies due to, for example, differences in the thickness of the covering ceramic layer 2 or the pore density of the ceramic layer 2. Further, in the heater portion, variations in heater resistance occur due to slight differences in conditions during ceramic manufacturing. If such variations occur, for example, if you want to control the heater temperature to a predetermined temperature,
As shown in Figure 3, even if the same voltage is applied, the actual temperature will differ due to variations in heater resistance (temperature T1 and temperature T1).
2) Accurate temperature control is not possible.

Similarly, the output of the sensor section also varies from sensor to sensor due to the above-mentioned reasons, so even if the value of the supply current IS is the same, the detected air-fuel ratio value will be different, as shown in FIG. It is difficult to detect the air-fuel ratio at the same time, making it impossible to control the vehicle optimally. FIG. 5 is a schematic configuration diagram of an air-fuel ratio control device using the oxygen sensor described above.

In FIG. 5, reference numeral 11 is the oxygen sensor described above, and its tip is inserted into the exhaust pipe 10. Also, from the oxygen sensor, a sensor part signal 11a and a heater part signal 11
b is outputted and inputted to an A/D converter 16 in a control unit 15, which will be described later, via the connector 12 and the connector 14. 13, depending on the magnitude of the variation in output between the sensor section signal 11a and the heater section signal 11b,
This is a resistor (adapter) selected by a method described later and connected within the connector 12.

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

[0016] Furthermore, the CP in the control unit 15
U17 detects the output V obtained by A/D converting the output 13a from the resistor 13 provided outside the control unit 15, and detects the output V obtained by A/D converting the output 13a from the resistor 13 provided outside the control unit 15, and operates a sensor section and a heater section that form two control conditions for the oxygen sensor 11 according to the output V. A correction coefficient for compensating for variations in is selected from the ROM 18. Then, calculations are performed to compensate for variations by taking this correction coefficient into account and to perform accurate vehicle control. Note that one end of the resistor 13 is connected to the power supply +B via the connector 14.

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

In this embodiment, the control unit 15
The correction coefficient K for compensating for variations in the output of the sensor section of the oxygen sensor 11 and the heater resistance (set so that the product variations become the design target value by multiplying each value by the correction coefficient K) is: A specific combination of the sensor section and heater section of the oxygen sensor 11 is set in advance so that the same value is obtained. In other words, the correction coefficient Ki of the sensor section and the correction coefficient Kt of the heater resistance are equal (K=Ki=K
t ).

Therefore, as shown in the table below (Table 1), when there are two control conditions (sensor output, heater resistance) and each control condition has five elements, for example, if the correction coefficient Ki is 1. The output of the sensor unit when the oxygen concentration is 0 is 7.5% is 12.8 to 13.2 [mA], and the temperature at which the correction coefficient Kt is 1.0 is 23°C. When the heater resistance value is 1.18 to 1.22 [Ω
] and a heater part with a resistance value belonging to [
The resistor 13 is set so that the voltage becomes [V].

[0020] Fig. 6 is a diagrammatic representation of each element in Table 1, and the horizontal axis shows the output of the sensor section when the oxygen concentration is 7.5% and the value of the heater resistance when the temperature is 23°C. , the output V of the A/D converter 16 is shown on the vertical axis.

[0021]

[Table 1]

Next, the control unit 15 based on the above combination
The operation will be explained using the flowchart shown in FIG.

When power is supplied, initialization processing 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, which is the output V.
Load. In step 120, based on the output V from the A/D converter 16 read in step 110, correction coefficients Ki and Kt are determined from a map as shown in FIG. 8, which is stored in the storage device 18 in advance. Note that the map shown in FIG. 8 is created corresponding to the table (Table 1) used when combining the sensor section and heater section described above.

In step 130, the detection signal and heater temperature from the sensor section of the oxygen sensor 11 are read, and in step 140, the values read in step 130 are multiplied by the correction coefficients Ki and Kt obtained in step 120, respectively, to obtain the signal from the sensor section. The detection signal and the heater temperature are corrected, and based on the correction values, arithmetic processing is executed in a main routine (not shown) to perform optimal vehicle control.

As described above, in this embodiment, by combining the output of the sensor section and the heater resistance in advance so that the correction coefficients are the same, it is possible to share the map for determining the correction coefficients Ki and Kt. Another advantage is that the correction coefficients Ki and Kt can be determined using the map. In addition, the combination of the output of the sensor section and the heater resistance is shown in Figure 13.
In this case, by rewriting the map stored in the storage device 18 as shown in FIGS. 14 and 15, variations in each control condition can be corrected.

In this embodiment, when setting the combination of the sensor section and the heater section of the oxygen sensor 11 in advance, the sensor section and the heater section were divided into five parts depending on the variations in these parts, and each was combined. In particular, it is not necessary to make the number of divisions the same. Next, the present invention will be explained in more detail based on a second example in which the combination conditions are different from those in the above example.

In the oxygen sensor 11 shown in the above embodiment, the output when the oxygen concentration of the sensor section is 7.5% and the resistance of the heater at 23° C. are measured, and the number is calculated for each measured value to calculate the frequency distribution. When the table is created, Figures 9 and 10
Variations as shown in will occur. Therefore, as shown in FIG. 9, the dispersion distribution of the output of the sensor section is small, so
Depending on the variation distribution, the number of divisions may be reduced as shown in the table below (Table 2), and the number of elements of the control conditions may be reduced. Note that FIG. 11 is a diagrammatic representation of Table 2 similar to FIG. 8.

[0028]

[Table 2]

Hereinafter, the sensor section and the heater section are combined based on Table 2, a resistor 13 corresponding to the combination is set, and the resistor 13 is installed outside the control unit 15 as shown in FIG.
The control unit 15 selects a correction coefficient from the ROM 18 according to the output of the resistor 13, and
Vehicle control is executed based on the flowchart shown in FIG. 7 similarly to the embodiment.

[0030] In this way, by dividing and combining according to the variation distribution, combinations can be set without leaving any sensor sections or heater sections. Next, in the above example, control conditions (sensor output, heater resistance)
However, a case where there are two or more control conditions will be described in detail based on the third embodiment.

For example, when controlling a vehicle using two of the oxygen sensors 11 described above (for example, when oxygen sensors are disposed before and after a catalyst that purifies 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, if the area is divided in the same way as Tables 1 and 2 according to the output of the sensor section and the value of the heater resistance, the results are as shown in Table 3, with i1 to i6 and r1 to r6 for each area.

Here, as shown below, for example, sensor A
Output i1, sensor B output i4, heater A resistance r1
and heater B resistance r4, the corresponding resistance 13 is set to 1 by combining each element of all control conditions.
For example, sensor A output i1, sensor B output i4, and heater A resistance r1 may be set.
One resistor 13 may be set by combining them based on a predetermined law, or one resistor 13 may be set by combining only the sensor B output i4 and the heater B resistance r4.

[0033]

[Table 3]

In this way, at least one of the elements under different control conditions is combined, and the resistance 1 corresponding to this combination is
By setting 3, the types of resistors 13 required can be reduced, and the circuits to which resistors 13 are connected can also be reduced, so the number of A/D converters and ports associated with this can also be minimized. It can be suppressed. Furthermore, as described above, by combining all elements under different control conditions, the types of resistors 13 can be minimized.

In this embodiment, a resistor (resistance 13) is used as a means for notifying the control unit 15 of the combination of control conditions, but other output signals such as a coil or a transmitter may be used to notify the control unit 15 of the combination of control conditions. You may let them know. Further, in this embodiment, the resistor 13 is provided inside the adapter 12 because it is advantageous in the manufacturing process, but the resistor 13 is not limited thereto, and may be provided around the control unit 15, for example.

Further, in this embodiment, the resistor 13 is provided for the purpose of correcting variations in the output of the sensor section of the oxygen sensor 11 and the heater resistance, but of course, other control conditions such as the vehicle type and the sensor manufacturer, etc. A resistor 13 may be provided for the purpose of correcting variations.

[0037]

As described above, in the present invention, by combining the elements of each control condition in advance, even if the number of elements of each control condition and the control conditions themselves become large, the number of adapters and the types of adapters can be controlled. This can improve work efficiency and reduce costs. Furthermore, the excellent effect of reducing the number of circuits to which the adapter is connected and the number of ports of the control unit can be achieved.

[Brief explanation of the drawing]

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

FIG. 2 is a characteristic diagram of the oxygen sensor shown in FIG. 1.

3 is an output characteristic diagram of the heater section of the oxygen sensor shown in FIG. 1. FIG.

4 is an output characteristic diagram of the sensor section of the oxygen sensor shown in FIG. 1. FIG.

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

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

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

FIG. 8 is a map for determining correction coefficients in the control unit.

FIG. 9 is a diagram showing the frequency distribution of the output of the sensor section in the second example.

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

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

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

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

FIG. 14 is a map for determining correction coefficients in the control unit.

FIG. 15 is a map for determining correction coefficients in the control unit.

[Explanation of symbols]

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

Claims (1)

[Claims] 1. Vehicle control comprising an adapter that outputs electrical signals corresponding to at least two different control conditions, and controlling the vehicle by selecting a control element indicating the nature of each control condition based on the output of the adapter. 1. A vehicle control method, characterized in that a specific combination of control elements between the different control conditions is determined in advance, and the adapter is set according to this combination.