JP6797065B2 - In-vehicle electronic control device - Google Patents

Description

The present invention relates to an in-vehicle electronic control device that controls the operation of a vehicle based on a detection result detected by a sensor.

Conventionally, a vehicle is equipped with an in-vehicle electronic control device composed of a microcomputer or the like that functions as a control center that electrically controls the operation of the engine or the like of the vehicle. In this control device, sensor detection signals detected by various sensors that collect various information necessary for control are input, and various controls are performed based on the input sensor detection signals.

Although various sensors are mounted on the vehicle, a throttle position sensor that indicates the opening degree of the accelerator is known as a sensor that outputs the state of the vehicle as a detection signal voltage with respect to the potential difference between the ground terminal and the power supply terminal of the sensor. ing.

For example, in the document shown below (see Patent Document 1), as shown in FIG. 2, a first monitor circuit that divides and monitors the power supply voltage VCS which is the reference voltage of the A / D converter 4 and a power supply to the sensor 2 A second monitor circuit is provided to divide and monitor the voltage AVCC of the power supply terminal 8 that supplies the voltage, and corrects the detection signal of the sensor 2 based on the A / D conversion values of V1 and V2, which are the output of each monitor circuit. ing. Here, the voltage AVCC is a voltage tracker output that follows the power supply voltage VCS with a certain degree of accuracy.

Further, by returning the voltage AVCC of the power supply terminal 8 that supplies power to the sensor 2 to the power supply circuit 6, a power supply circuit with a feedback control function that controls the voltage AVCC of the power supply terminal 8 to be constant is used, and the sensor is used. A configuration that suppresses fluctuations in the power supply voltage AVCC of 2 is generally known.

JP-A-2007-69741

Since the current of the power supply supplied to the sensor 2 fluctuates depending on the state of the sensor 2, in the configuration of Patent Document 1 and the conventional configuration using the power supply circuit with the feedback function, the error of the sensor detection signal due to the voltage fluctuation of the power supply terminal 8 However, the voltage drop caused by the resistance of the power supply of the sensor 2 and the harness connected to the ground cannot be taken into consideration, and the detection signal voltage with respect to the potential difference between the ground terminal and the power supply terminal of the sensor 2 is output. The error of the sensor detection signal cannot be sufficiently corrected.

Therefore, the present invention has been made in view of the above, and an object of the present invention is to reduce the error of the detection signal of the sensor of the method of outputting the detection signal voltage with respect to the potential difference between the ground terminal and the power supply terminal of the sensor. The present invention is to provide an in-vehicle electronic control device having improved vehicle controllability based on the detection result of the sensor.

In order to achieve the above object, the invention according to claim 1 is a sensor that outputs the state of the vehicle as a detection signal voltage with respect to a potential difference between the ground terminal and the power supply terminal of the sensor, and a power supply circuit that generates and outputs a power supply voltage. An A / D converter that A / D-converts the sensor detection signal of the sensor using the power supply voltage output from the power supply circuit as a reference voltage, and A of the sensor detection signal obtained by the A / D converter. In an in-vehicle electronic control device having a control means for controlling the operation of the vehicle based on the / D conversion value, it is provided in the middle of the board wiring from the power supply circuit to the power supply terminal for supplying power to the sensor. An A / D converter that A / D converts the voltage at the branch point, a resistance value from the power supply circuit to the branch point, a resistance value from the branch point to the power supply terminal, and the sensor from the power supply terminal. A storage device for storing the resistance value of the harness or the like up to and the resistance value of the harness or the like from the sensor to the ground terminal of the in-vehicle electronic control device is provided, and the control means is obtained by the A / D converter. The A / D conversion value of the sensor detection signal obtained by the A / D converter using the A / D conversion value of the voltage at the branch point and the four resistance values stored in the storage device. It is characterized by correcting.

According to the invention according to claim 1 of the above-mentioned feature, the four resistance values required in advance are stored in the storage device, and the A / D conversion value of the sensor detection signal is appropriately stored together with the voltage monitoring result of the branch point. By correcting, it is possible to reduce the error of the detection signal of the sensor of the method of outputting the detection signal voltage with respect to the potential difference between the ground terminal and the power supply terminal of the sensor. As a result, the controllability of the vehicle based on the detection result of the sensor can be improved.

The invention according to claim 2 is the resistance value from the power supply circuit to the branch point among the four resistance values stored in the storage device in the in-vehicle electronic control device according to claim 1, and the branch point. The resistance value from the power supply terminal to the power supply terminal is characterized in that each resistance value is stored as an absolute value.

According to the invention according to claim 2 of the above-mentioned feature, the absolute value such as the resistance value measured in advance and the theoretical resistance value obtained from the design information such as the width, length, and thickness of the board wiring is stored. By doing so, various voltage values and the like, which will be described later, can be directly obtained.

The invention according to claim 3 is the resistance value from the power supply circuit to the branch point among the four resistance values stored in the storage device in the in-vehicle electronic control device according to claim 1, and the branch point. The resistance value from to the power supply terminal is characterized in that one of the resistance values is stored as an absolute value and the other is stored as a ratio to the resistance value of the other.

According to the invention according to claim 3 of the above characteristics, only one resistance value can be measured as an absolute value, and the other can be stored as a designly determined ratio, thereby simplifying the manufacturing process. It is possible. Further, even when the theoretical resistance value is stored instead of the measured value, it is possible to simplify the calculation formula by storing the other as a ratio. For example, when the ratio is 1: 1, the absolute values of both are equal, and the parameter used for calculation can be reduced by one.

The invention according to claim 4 is the resistance value of a harness or the like from the power supply terminal to the sensor among the four resistance values stored in the storage device in the in-vehicle electronic control device according to claim 1. The resistance value of the harness or the like from the sensor to the ground terminal of the vehicle-mounted electronic control device is characterized in that each resistance value is stored as an absolute value.

According to the invention according to claim 4 of the above-mentioned feature, the absolute value such as the resistance value of the harness or the like measured in advance and the theoretical resistance value obtained from the design information such as the thickness and length of the lead wire of the harness. By storing the above, various voltage values and the like, which will be described later, can be directly obtained.
The invention according to claim 5 is the resistance value of a harness or the like from the power supply terminal to the sensor among the four resistance values stored in the storage device in the in-vehicle electronic control device according to claim 1, and the said. The resistance value of the harness or the like from the sensor to the ground terminal of the in-vehicle electronic control device is characterized in that one of the resistance values is stored as an absolute value and the other is stored as a ratio to the resistance value of the other. ..

According to the invention according to claim 5 of the above-mentioned characteristics, only one resistance value can be measured as an absolute value, and the other can be stored as a ratio obtained by design, thereby simplifying the manufacturing process. It is possible. Further, even when the theoretical resistance value is stored instead of the measured value, it is possible to simplify the calculation formula by storing the other as a ratio. For example, when the ratio is 1: 1, the absolute values of both are equal, and the parameter used for calculation can be reduced by one.

The invention according to claim 6 is an A / D conversion of the voltage at the branch point with respect to four resistance values stored in the storage device in the in-vehicle electronic control device according to claims 1 to 5. The input resistance value of the / D converter is sufficiently large.

According to the invention according to claim 6 of the above-mentioned characteristics, the current flowing from the branch point to the A / D converter is small and the voltage drop can be sufficiently small, so that the detection signal of the sensor can be corrected with high accuracy. ..

The invention according to claim 7 A / D-converts a sensor detection signal of the sensor with respect to four resistance values stored in the storage device in the in-vehicle electronic control device according to claims 1 to 5. The input resistance value of the A / D converter is sufficiently large.

According to the invention according to claim 7 of the above-mentioned feature, the current flowing from the sensor to the A / D converter is small, and the voltage drop can be sufficiently small, so that the detection signal of the sensor can be corrected with high accuracy.

The invention according to claim 8 is the in-vehicle electronic control device according to any one of claims 1 to 5, wherein the four resistance values stored in the storage device are subjected to the ground terminal of the in-vehicle electronic control device to the MPU. The resistance value to the ground terminal is sufficiently small.

According to the invention according to claim 8 of the above-mentioned feature, since the voltage drop due to the current flowing from the ground terminal to the MPU can be sufficiently reduced, the detection signal of the sensor can be corrected with high accuracy.

It is a figure which shows the structure of the electronic control device for vehicle which concerns on Example 1 of this invention. It is a figure which shows the structure of the conventional electronic control device for vehicle.

Hereinafter, the best examples for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an in-vehicle electronic control device according to a first embodiment of the present invention. The in-vehicle electronic control device 1 of the first embodiment shown in FIG. 1 is characterized by the wiring resistance Rcom from the power supply circuit 6 to the branch point S3 and the power supply terminal from the branch point S3 with respect to the configuration shown in FIG. A storage device that stores the wiring resistance Ra up to 8, the resistance Rh of the harness or the like from the power supply terminal 8 to the sensor 2, and the resistance Rg of the harness or the like from the sensor 2 to the ground terminal 9 of the in-vehicle electronic control device 1. It is equipped with 10.

The voltage dividing resistors R3 and R4 of the monitor circuit of FIG. 2 are provided so that the A / D converter 4 of the MPU 3 can monitor a voltage higher than the power supply voltage VCS, and in this embodiment, it is provided. Is also applicable, but omitted for simplification of explanation.

The resistance of the harness etc. from the power supply terminal 8 to the sensor 2 is Rh, the resistance of the harness etc. from the sensor 2 to the ground terminal 9 is Rg, the wiring resistance from the power supply circuit 6 to the branch point S3 is Rcom, and the power supply terminal from the branch point S3. Based on the voltage Vcom of the branch point S3 read by the MPU 3 and the detection signal V1 of the sensor 2 read by the MPU 3, the wiring resistance value up to 8 is Ra, and the potential difference Vs between the power supply side voltage Vsp and the ground side voltage Vsg of the sensor 2 And, the ratio Radio of Vout to Vs can be obtained by the following formula.

Power supply side voltage of sensor Vsp = AVCC- (AVCC-Vcom) x (Rcom + Ra + Rh) / Rcom
Sensor ground side voltage Vsg = (AVCC-Vcom) x Rg / Rcom
Therefore, the potential difference Vs between the power supply side voltage Vsp and the ground side voltage Vsg of the sensor is
Vs = AVCC- (AVCC-Vcom) x (Rcom + Ra + Rh-Rg) / Rcom
Detection signal of sensor 2 read by A / D converter 4 of MPU3 V1 = Vout + (AVIC-Vcom) x Rg / Rcom
Therefore, the ratio of Vout to Vs is
Ratio = Vout / Vs
= (Rcom x V1- (AVCC-Vcom) x Rg) / (Rcom x Vcom- (AVCC-Vcom) x (Ra + Rh + Rg))
Here, since the output voltage AVCC of the power supply circuit 6 is known and the values of the resistors Rcom, Ra, Rh, and Rg are stored in the storage device 10 of the MPU 3, the power supply side voltage Vsp and the ground side voltage Vsg of the sensor 2 are stored. The ratio of Vout to the potential difference Vs Radio can be calculated from the detection signal V1 of the sensor 2 read by the A / D converter 4 of the MPU 3.

Here, by expressing Ra by the ratio of Rcom, Ra as a parameter can be eliminated from the above calculation formula. Of course, if Rcom is expressed by the ratio of Ra, Rcom as a parameter can be erased. Similarly, if Rg is expressed by the ratio of Rh, Rg as a parameter can be eliminated, and if Rh is expressed by the ratio of Rg, Rh as a parameter can be eliminated from the above formula.

The V1 and Vcom of the Ratio equation are the values detected by the A / D converter 4 of the MPU3, and the reference voltage VCS of the A / D converter 4 is within the tolerance range (for example, +0) from the design value (for example, 5.00V). It can be seen that even if the fluctuation is (/ −0.10 V), the tolerance variation of the VCS is absorbed.

The AVCC of the Ratio equation is a voltage tracker output voltage that follows the power supply voltage VCS with a certain accuracy (for example, +/- 0.01V), and the tolerance variation of the VCS is absorbed and the resistance Rcom, It is smaller than the voltage drop at Ra, Rh, and Rg (for example, it fluctuates between 0.00V and 0.20V depending on the fluctuating current supplied to the sensor 2).

The physical quantity indicating the state of the vehicle detected by the sensor 2 is the ratio of Vout to the potential difference Vs of the power supply side voltage Vsp and the ground side voltage Vsg of the sensor 2, that is, Rio.

Therefore, the sensor that fluctuates depending on the state of the sensor 2 by correcting the input signal V1 from the sensor 2 from the values of the resistors Rcom, Ra, Rh, and Rg stored in the storage device 10 of the MPU3 and the voltage Vcom of the branch point S3. It is possible to reduce the error of the detection signal of the sensor 2 due to the current of 2 and the resistance of the harness or the like.

It is preferable that the input resistance value of the A / D converter 4 is sufficiently larger than the resistance value stored in the storage device 10. The voltage Vcom at the branch point S3 read by the A / D converter 4 of the MPU 3 has the same potential as the branch point S3, and a voltage drop is unlikely to occur, so that the accuracy is further improved.

Similarly, the input resistance value of the A / D converter 4 of the MPU 3 that reads the detection signal V1 of the sensor 2 should be sufficiently larger than the resistance value stored in the storage device 10.

If the ground resistance value of the in-vehicle electronic control device is sufficiently smaller than the resistance value stored in the storage device 10, the ground terminal of the in-vehicle electronic control device 1 and the ground terminal of the MPU 3 have the same potential, and a voltage drop occurs. Since it is difficult, the accuracy is improved.

1 ... In-vehicle electronic control device 2 ... Sensor 3 ... MPU
4 ... A / D converter 5 ... Battery terminal 6 ... Power supply circuit 7 ... Ground terminal 8 ... Power supply terminal 9 ... Ground terminal 10 ... Storage device R1 to R4 ... Resistance Rcom, Ra ... Wiring resistance Rh, Rg ... Resistance of harness, etc.

Claims (8)

A sensor ( 2 ) that outputs the state of the vehicle as a detection signal voltage with respect to the potential difference between the ground terminal and the power supply terminal of the sensor.
A power supply circuit ( 6 ) that generates and outputs a power supply voltage, and
An A / D converter ( 4 ) that A / D-converts the sensor detection signal of the sensor using the power supply voltage output from the power supply circuit ( 6 ) as a reference voltage.
In an in-vehicle electronic control device having a control means ( MPU3 ) for controlling the operation of the vehicle based on the A / D conversion value of the sensor detection signal obtained by the A / D converter ( 4 ) .
The A / D converter (4), said power supply circuit (6) from the provided in the middle of the substrate wiring to the power supply terminal (8) for supplying power to said sensor (2) branch point (S3) A / D conversion of voltage,
The control means has a resistance value from the power supply circuit ( 6 ) to the branch point ( S3 ) , a resistance value from the branch point ( S3 ) to the power supply terminal ( 8 ), and a resistance value from the power supply terminal ( 8 ). storage device for storing a resistance value of the harness or the like to the power supply, the resistance value of the harness or the like from said sensor (2) until said vehicle electronic control equipment of the ground terminal (9) of the sensor (2) (10) With
The control means converts the A / D conversion value of the voltage at the branch point ( S3 ) obtained by the A / D converter ( 4 ) and the four resistance values stored in the storage device ( 10 ). An in-vehicle electronic control device, which is used to correct an A / D conversion value of the sensor detection signal obtained by the A / D converter ( 4 ) . Of the four resistance values stored in the storage device ( 10 )
The resistance value from the power supply circuit ( 6 ) to the branch point ( S3 ) ,
The resistance value from the branch point ( S3 ) to the power supply terminal ( 8 ) is
The vehicle-mounted electronic control device according to claim 1, wherein each resistance value is stored as an absolute value. Of the four resistance values stored in the storage device ( 10 )
The resistance value from the power supply circuit ( 6 ) to the branch point ( S3 ) ,
The resistance value from the branch point ( S3 ) to the power supply terminal ( 8 ) is
The vehicle-mounted electronic control device according to claim 1, wherein one of the resistance values is stored as an absolute value, and the other is stored as a ratio to the resistance value of the other. Of the four resistance values stored in the storage device ( 10 )
The resistance value of the harness or the like from the power supply terminal ( 8 ) to the sensor ( 2 ) ,
The resistance of the harness or the like from said sensor (2) until said vehicle electronic control equipment of the ground terminal (9),
The vehicle-mounted electronic control device according to claim 1, wherein each resistance value is stored as an absolute value. Of the four resistance values stored in the storage device ( 10 )
And the resistance value of the harness or the like from the power supply terminal (8) to the sensor (2), the resistance value of the harness or the like from said sensor (2) until said vehicle electronic control equipment of the ground terminal (9), either The vehicle-mounted electronic control device according to claim 1, wherein one of the resistance values is stored as an absolute value and the other is stored as a ratio with respect to the one resistance value. For the four resistance values stored in the storage device ( 10 )
Vehicle according to any of the A / D converter (4) according to claim claim 1 towards the input resistance of the voltage of the branch point (S3) to be inputted, wherein the large heard 5 Electronic control device for. For the four resistance values stored in the storage device ( 10 )
Vehicle as claimed in claim 1, characterized in that towards the A / D converter input resistance of the sensor detection signal of the sensor that is input to (4) (2) is larger in any of claims 5 Electronic control device for. For the four resistance values stored in the storage device ( 10 )
Claim 5 is, the resistance of the from the in-vehicle electronic control equipment of the ground terminal (9) ground to pin (7) of said control means (MPU 3) from claim 1, wherein the small again In-vehicle electronic control device according to.

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