JP3750617B2 - Electronic control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic control device for an internal combustion engine to which an external connection device such as a diagnostic tester is connected as necessary as a service tool.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in communication between an internal combustion engine electronic control device and an externally connected device such as a diagnostic tester, one using asynchronous communication that reads communication data on the transmission side at a timing based on an internal clock on the reception side is known. As a communication protocol at this time, for example, KWP2000 of ISO14230 is used. In this KWP2000, an initialization command is generally used in connection confirmation with an externally connected device, and only when the initialization command from the externally connected device side is normal, a communication response with the electronic control device side. Then, the communication data can be exchanged thereafter.
[0003]
[Problems to be solved by the invention]
By the way, the pulse width and interval (time) in the communication data initialization command from the externally connected device are, for example, about 1 [ms: milliseconds] at the reception port on the electronic control unit side. Since the determination is made by detecting the fall or the rise, a tolerance of about 2 [ms] at the maximum is usually required, and the measurement cannot be performed more accurately. For this reason, in the connection permission determination for communication response, a predetermined allowable range is provided for the width and interval of the measured pulse. Here, if the pulse edge in the communication data initialization command from the external device is dull, even if it is a legitimate device, the connection for the communication response is not permitted, and conversely, it is not legitimate. There is a problem that the connection for communication response is permitted even if the device is out of a predetermined allowable range.
[0004]
Accordingly, the present invention has been made to solve such a problem, and an object thereof is to provide an electronic control device for an internal combustion engine that can accurately perform connection permission determination for communication response with an externally connected device.
[0005]
[Means for Solving the Problems]
According to the electronic control device for an internal combustion engine of claim 1, when the communication data from the external connection device is started to be received through the reception port, the measurement data from the external connection device sequentially captured by the capture input port is received. The fall time and rise time of a series of pulses in the communication data initialization command are measured, and when the pulse width and interval based on this measurement are within a preset time range, the externally connected device is properly The communication response after that is permitted. Thereby, the connection permission determination for a communication response with an external connection apparatus is implemented accurately.
[0006]
3. The permission mode in the electronic control device for an internal combustion engine according to claim 2, wherein the reception port can receive a start word read after that at a measurement timing which is a final rising time of a series of pulses in the initialization command. Can be switched in advance. This provides the effect that the start word following a series of pulses in the initialization command is read correctly from the beginning at the receiving port.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples.
[0008]
FIG. 1 is a block diagram showing a schematic configuration of an electronic control device for an internal combustion engine according to an example of an embodiment of the present invention and a connection state with an external connection device.
[0009]
In FIG. 1, reference numeral 100 denotes an internal combustion engine ECU (Electronic Control Unit). The ECU 100 is illustrated in addition to an MPU (Micro-Processor Unit) 10 as a central processing unit that executes various known arithmetic processes. It is configured as a logical operation circuit comprising a ROM storing control programs and control maps, a RAM storing various data, a B / U (backup) RAM, an input / output circuit and a bus line connecting them, An interface 20 for transmitting and receiving communication data is provided. The MPU 10 includes a reception port Rx, a transmission port Tx, and a capture input port TI04B.
[0010]
The ECU 100 is connected to an external connection device 200 such as a diagnostic tester as a service tool through a single transmission / reception communication line L1. Then, in the ECU 100 to which the communication line L1 is connected, one of the two branches of the connection line is further branched into two via the interface 20, one is the receiving port Rx of the MPU 10, and the other one is The MPU 10 is connected to the capture input port TI04B. Further, the remaining one of the two connection lines is connected to the transmission port Tx of the MPU 10 via the interface 20.
[0011]
With the above configuration, communication data input from the external device 200 through the communication line L1 to the ECU 100 is received via the interface 20 at the reception port Rx of the MPU 10. At the same time, communication data input from the external device 200 to the ECU 100 is directly input to the capture input port TI04B of the MPU 10 via the interface 20. Then, the falling time and rising time of a series of pulses in the communication data initialization command input to the capture input port TI04B of the MPU 10 are sequentially captured. The capture input port TI04B can capture the fall time and rise time of a series of pulses in the communication data initialization command in about [μs: microseconds] as a time unit. Further, communication data from the transmission port Tx of the MPU 10 is transmitted from the ECU 100 via the interface 20 to the external connection device 200 through the communication line L1.
[0012]
Next, the block diagram of FIG. 2 which shows the modification of FIG. 1 is demonstrated. In the figure, components having the same configuration or corresponding parts as in FIG. 1 are denoted by the same reference numerals and symbols.
[0013]
FIG. 2 is different in that the ECU 100 ′ and the external connection device 200 ′ are connected by two independent communication lines L11 and L12 on the reception side and the transmission side. In the ECU 100 ′ to which the communication line L 11 for communication from the external connection device 200 ′ to the ECU 100 ′ is connected, the connection line is branched into two via the interface 20, one of which is a receiving port of the MPU 10. Rx and the other one are connected to the capture input port TI04B of the MPU 10, respectively. In addition, in the ECU 100 ′ to which the connection line L12 for communication from the ECU 100 ′ side to the external connection device 200 ′ side is connected, the connection line is connected to the transmission port Tx of the MPU 10 via the interface 20.
[0014]
With the above configuration, communication data input from the external device 200 ′ through the communication line L 11 to the ECU 100 ′ is received via the interface 20 at the reception port Rx of the MPU 10. At the same time, communication data input from the external device 200 ′ to the ECU 100 ′ is directly input to the capture input port TI04B of the MPU 10 via the interface 20. The MPU 10 sequentially captures the falling time and the rising time of a series of pulses in the communication data initialization command input to the capture input port TI04B. Further, communication data from the transmission port Tx of the MPU 10 is transmitted from the ECU 100 ′ via the interface 20 to the external connection device 200 ′ through the communication line L12.
[0015]
Next, a communication response with the external connection device 200 (200 ′) in the MPU 10 in the ECU 100 (100 ′) used in the electronic control device for an internal combustion engine according to an example and a modification of the embodiment of the present invention. A description will be given with reference to FIG. 4 based on the flowchart of FIG. FIG. 4 is a time chart showing the relationship between the communication data initialization command corresponding to the processing of FIG. 3 and the capture time.
[0016]
In FIG. 3, first, in step S101, the time from the capture time T01 (see FIG. 4) at which the fall of the pulse in the communication data initialization command is captured to the capture time T02 (see FIG. 4) at which the rise of the pulse is captured. Is longer than 22 [ms] and shorter than 28 [ms]. When the determination condition of step S101 is satisfied, that is, when the inequality of 22 [ms] <(T02−T01) <28 [ms] is satisfied, the process proceeds to step S102, and the 10.4 [kbps: kilobit per second] reception mode is set. Is done. That is, at this time, the 10.4 [kbps] reception mode for reading the connection ID code of the start word in the initial command of communication data described later is set in advance.
[0017]
Next, the process proceeds to step S103, from the capture time T03 (see FIG. 4) at which the falling edge of the start bit of the connection ID code of the start word following the pulse in the communication data initialization command to the above-described capture time T01. It is determined whether the time is longer than 47 [ms] and shorter than 53 [ms]. When the determination condition in step S103 is satisfied, that is, 47 [ms] <(T03-T01) <53 [ms], the communication data initialization command is determined to be normal, and the process proceeds to step S104, and the external connection device 200 ( 200 ') is executed, and this routine is terminated. In this communication response process, first, it is determined whether the connection ID code of the start word in the communication data initialization command is coincident or not, and when the connection ID code of the start word matches, the communication response by the subsequent communication data is executed. Is done. When the connection ID code of the start word in the initialization command does not match, the communication response by the communication data is rejected.
[0018]
On the other hand, when the determination condition of step S101 is not satisfied, that is, when the time from the capture time T01 to the capture time T02 is shorter than 22 [ms] or longer than 28 [ms], or the determination condition of step S103 is satisfied. That is, when the time from the capture time T01 to the capture time T03 is shorter than 47 [ms] or longer than 53 [ms], the process proceeds to step S105, and it is determined that the communication data initialization command is abnormal. After initialization for communication check is executed, the process returns to step S101, and the same processing is repeatedly executed. If the initialization command for communication data is not determined to be normal even if this routine is tried a plurality of times, a warning (not shown) is given and the routine is terminated.
[0019]
Next, a communication response with the external connection device 200 (200 ′) in the MPU 10 in the ECU 100 (100 ′) used in the electronic control device for an internal combustion engine according to an example and a modification of the embodiment of the present invention. Based on the flowchart of FIG. 5 which shows the modification of the processing procedure of the connection permission determination for, it demonstrates with reference to FIG. Here, FIG. 6 is a time chart showing the relationship between the communication data initialization command and the capture time corresponding to the processing of FIG.
[0020]
In FIG. 5, first, in step S201, the capture time T12 (see FIG. 6) at which the rising edge of the first pulse is captured from the capture time T11 (see FIG. 6) at which the falling edge of the first pulse in the communication data initialization command is captured. 6) is determined whether it is longer than 7 [ms] and shorter than 13 [ms]. When the determination condition of step S201 is satisfied, that is, when the inequality of 7 [ms] <(T12−T11) <13 [ms] is satisfied, the process proceeds to step S202.
[0021]
Next, the process proceeds to step S202, and the time from the capture time T12 at which the rising edge of the first pulse in the communication data initialization command is captured to the capture time T13 (see FIG. 6) at which the falling edge of the second pulse is captured. Is longer than 7 [ms] and shorter than 13 [ms]. When the determination condition of step S202 is satisfied, that is, when the inequality of 7 [ms] <(T13−T12) <13 [ms] is satisfied, the process proceeds to step S203, and the capture time T13 when the falling edge of the second pulse is captured. To the capture time T14 when the rising edge of the second pulse is captured is determined whether it is longer than 7 [ms] and shorter than 13 [ms]. When the determination condition of step S203 is satisfied, that is, when the inequality of 7 [ms] <(T14−T13) <13 [ms] is satisfied, the communication data initialization command is assumed to be normal, and the process proceeds to step S204. bps: bits per second] The reception mode is set. That is, at this time, the 9600 [bps] reception mode for reading the connection ID code of the start word in the initial command of communication data described later is set in advance.
[0022]
Next, the process proceeds to step S205, a communication response process with the external device 200 (200 ′) is executed, and this routine is terminated. In this communication response process, first, it is determined whether the connection ID codes of the start word following the two pulses in the communication data initialization command match, and when the connection ID codes of the start word match, the subsequent communication data The communication response by is executed. When the connection ID code of the start word in the initialization command does not match, the communication response by the communication data is rejected.
[0023]
On the other hand, the determination condition of step S201 is not satisfied, that is, when the time from the capture time T11 to the capture time T12 is shorter than 7 [ms] or longer than 13 [ms], or the determination condition of step S202 is satisfied. That is, when the time from the capture time T12 to the capture time T13 is shorter than 7 [ms] or 13 [ms], or the determination condition of step S203 is not satisfied, that is, from the capture time T13 to the capture time T14. If the time is shorter than 7 [ms] or 13 [ms], the process proceeds to step S206, and it is determined that the communication data initialization command is abnormal. The same processing is repeatedly executed. If the initialization command for communication data is not determined to be normal even if this routine is tried a plurality of times, a warning (not shown) is given and the routine is terminated.
[0024]
As described above, the ECU 100 (100 ′) as the electronic control device for the internal combustion engine of the present embodiment and the modification is connected to the external connection device 200 (200 ′), and the MPU 10 for performing mutual communication by asynchronous communication. When reception of communication data from the reception port Rx and the transmission port Tx and the external connection device 200 (200 ') is started via the reception port Rx, a predetermined number of pulses of communication data input to the reception port Rx and the subsequent pulses The pulse width and interval are measured based on the capture input port TI04B of the MPU 10 that sequentially captures the fall time and rise time of a series of pulses in the initialization command consisting of the start word, and the time captured at the capture input port TI04B. The measuring means achieved by the MPU 10, the width of the pulse by the measuring means, and When septum becomes a preset time range is to a granted means achieved by MPU10 to allow communication response with the external connection device 200 (200 ').
[0025]
In other words, when the ECU 100 (100 ') side determines whether or not the external connection device 200 (200') is genuine, the external connection device sequentially captured at the capture input port TI04B of the MPU 10 of the ECU 100 (100 '). The fall time and rise time of a series of pulses in the communication data initialization command from 200 (200 ') are measured very accurately as the capture time, that is, in units of [μs]. When the pulse width and interval based on this measurement are within a preset time range, the ECU 100 (100 ′) recognizes that the externally connected device 200 (200 ′) is genuine, and the ECU 100 thereafter Communication response with (100 ') is allowed. Thereby, the connection permission determination for the communication response with the external connection device 200 (200 ′) in the ECU 100 (100 ′) can be accurately performed.
[0026]
In addition, the permission means achieved by the MPU 10 of the ECU 100 (100 ′) as the electronic control device for the internal combustion engine of the present embodiment and the modification is the reception port Rx at the final rising time of a series of pulses in the initialization command. Is switched to the reception mode of the connection ID code of the start word in the initialization command. That is, at the measurement timing that is the last rise time of a series of pulses in the initialization command, the reception port Rx is switched in advance to the reception mode in which the connection ID code of the start word that is read later can be received. As a result, the connection ID code of the start word following the series of pulses in the initialization command can be accurately read from the beginning.
[0027]
By the way, in the above-described embodiment and modification, the connection permission determination in the two specific examples of the communication data initialization command has been described. However, the present invention is not limited to this. According to the same method for various forms of the communication data initialization command, the connection permission determination can be performed accurately.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a schematic configuration of an electronic control device for an internal combustion engine according to an embodiment of the present invention and a connection state with externally connected devices.
FIG. 2 is a block diagram showing a schematic configuration of an internal combustion engine electronic control device according to a modification of FIG. 1 and a connection state with an external connection device.
FIG. 3 is a flowchart showing a communication response permission determination process in an MPU in an ECU used in an electronic control device for an internal combustion engine according to an embodiment and a modification of the embodiment of the present invention. .
4 is a time chart showing the relationship between a communication data initialization command corresponding to the processing of FIG. 3 and a capture time. FIG.
FIG. 5 shows a modified example of the processing procedure of the communication response permission determination in the MPU in the ECU used in the electronic control device for an internal combustion engine according to an example and a modified example of the embodiment of the present invention. It is a flowchart.
6 is a time chart showing the relationship between a communication data initialization command corresponding to the processing of FIG. 5 and a capture time. FIG.
[Explanation of symbols]
10 MPU
Rx reception port Tx transmission port TI04B Capture input port 100, 100 'ECU (electronic control unit)
200, 200 'Externally connected equipment

Claims (2)

A reception port and a transmission port connected to an external device and performing mutual communication by asynchronous communication;
When reception of communication data from the external connection device is started via the reception port, a series of pulses in an initialization command including a predetermined number of pulses of the communication data input to the reception port and a start word that follows the communication data. A capture input port that captures the falling and rising times in sequence,
Measuring means for measuring the width and interval of the pulse based on the time captured at the capture input port;
An electronic control device for an internal combustion engine, comprising: permission means for permitting a communication response with the external connection device when the width and interval of the pulse by the measuring means are within a preset time range. . 2. The internal combustion engine according to claim 1, wherein the permission unit switches the reception port to a start word reception mode in the initialization command at a last rising time of a series of pulses in the initialization command. Electronic control device.

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