JPH07131464A - Multiplex communication system for vehicle - Google Patents

Abstract

PURPOSE:To facilitate the incorporation of an option electronic control unit (ECU) and shipment inspection as to the multiplex communication system for the vehicle which makes a data communication among plural electronic control units(ECU) mounted on the vehicle. CONSTITUTION:Traction control 12, an air suspension 14, 4WS 16, 4WD 18, 'EFI(R)' 26, ABS 28, etc., are taken into consideration as the ECUs mounted on the vehicle. The ABS 28 needs to be controlled differently according to whether or not there is 4WD 18. Dummy data are sent out of the 'EFI(R)' 26 to the respective ECUs, each of which sends a response signal. According to, whether or not there is the response signal, the ABS 28 recognizes whether or not there is 4WD 18, and stores the result in a memory and selects and executes a control program corresponding to whether or not there is the 4WD.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle multiplex communication system, and more particularly to simplification of system configuration.

[0002]

2. Description of the Related Art In recent years, a large number of electronic control units (hereinafter referred to as ECUs) have been mounted as vehicles have become multifunctional. As such an ECU, ABS (anti-lock brake system), EFI (electronic fuel injection: registered trademark), ECT (electronic controlled transmission: registered trademark), etc. are known. When a large number of such ECUs are mounted on each vehicle, if each ECU has a sensor or the like necessary for signal processing, the ECUs will be redundantly mounted on the entire vehicle, which is disadvantageous in terms of cost and weight. Therefore, JP-A-64-5
As in the vehicle control computer device described in Japanese Patent Laid-Open No. 0156, one of a plurality of ECUs takes in a necessary electric signal and distributes it to other ECUs by multiplex communication so that a sensor, etc. It has been proposed to avoid redundant possession and reduce the wire harness for connecting each ECU.

[0003]

However, the ECU
Depending on the user's wishes, there is an option system, that is, an option system. In the above example, ABS is one of the option systems. When performing multiplex communication in a system equipped with such an optional system, the multiplex communication data differs depending on the presence or absence of the optional system, so that the contents of hardware and software change in each ECU. For this reason, the E
There was a problem that a CU was required.

FIG. 4 shows an example of a multiplex communication system equipped with various ECUs. In this example, EC
As U, ABS (1) 10, traction control 12, air suspension (abbreviated as air suspension) 14,
4WS16, 4WD18, air conditioner 20, auto drive 22, ECT (registered trademark) 24, EFI (registered trademark)
26 are provided. ABS (1) 10, traction control 12, 4WS16, 4WD18, etc. are optional systems. In this example, since the 4WD 18 is equipped as an optional system, the system ABS (1) 10 corresponding to the 4WD 18 is provided as the ABS. On the other hand, FIG. 5 shows an example of a multiplex communication system not equipped with 4WD as an optional system. As it is not equipped with 4WD, ABS is not ABS (1) but ABS
(2) 11 is required. As described above, different ECUs are required depending on the optional system added to the system, and there is a problem that the number of parts at the time of assembling the vehicle increases, work efficiency decreases, and maintenance work becomes complicated.

The present invention has been made in view of the above-mentioned problems of the prior art, and the purpose thereof is to use a common ECU regardless of an optional system, thereby improving work efficiency during vehicle assembly and maintenance work. It is an object of the present invention to provide a multiplex communication system for a vehicle, which can facilitate the above.

[0006]

In order to achieve the above object, a vehicle multiplex communication system according to claim 1 is a vehicle multiplex communication system for performing data communication between a plurality of electronic control units ECU mounted in a vehicle. A communication system, wherein one electronic control unit ECU among the plurality of electronic control unit ECUs
Has a transmission means for transmitting dummy data to another electronic control unit ECU, and the other electronic control unit ECU
At least one of them is a response means for transmitting a response signal according to the dummy data, an identification means for identifying another electronic control unit ECU connected to the system by the response signal, and an identification means for the identification means. Selecting means for selecting one control program from a plurality of predetermined control programs according to the identification result.

[0007]

The vehicle multiplex communication system of the present invention has the above-mentioned configuration, and transmits dummy data to each ECU from one of the electronic control units ECU, for example, EFI (registered trademark). Each ECU receives this dummy data and transmits a response signal, but does not respond to this dummy data when the optional system is not equipped. Therefore, depending on the presence or absence of the response signal, other E
The CU can recognize whether or not the optional system is equipped. Then, depending on the presence or absence of this optional system, each ECU selects a desired control program from among a plurality of preset control programs depending on the presence or absence of the optional system, and executes it.
One ECU can support the presence or absence of the optional system.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a vehicle multiplex communication system of the present invention will be described below with reference to the drawings.

FIG. 1 shows a system configuration diagram of this embodiment. Similar to the conventional system, traction control 12, air suspension 14, 4WS16, air conditioner 2
0, Autodrive 22, ECT (registered trademark) 24, E
FI (registered trademark) 26 is connected to each other, and further ABS2
8 is connected. As shown in FIGS. 4 and 5, the ABS in the conventional system is connected with a dedicated system having a dedicated control program according to the presence or absence of the optional system 4WD 18, but in the present embodiment, the presence or absence of the 4WD equipment is provided. Regardless of this, the common ABS 28 is connected. The ABS 28 is provided with a rewritable memory such as an EEPROM, and the ABS A control program software A and 4W when there is no 4WD.
Software B, which is an ABS control program when D is present
Are stored in the ROM. One of these ECUs, such as EFI (registered trademark), is installed when the vehicle is installed.
Is transmitted as a master ECU, the ABS 28 recognizes the presence or absence of 4WD from a response signal to the dummy data, and selects and executes a control program of either software A or software B.

FIG. 2 shows a processing flowchart of this embodiment. First, EF, which is the master ECU
Dummy data is transmitted from I (registered trademark) 26 to each ECU (S101). Each ECU that received the dummy data
Transmits a response signal in response to the dummy data. This response signal is received by all ECUs including the EFI (registered trademark) 26 which has transmitted the dummy data. And
It is determined whether a response signal has been received (S102).
For example, when the EFI (registered trademark) 26 sends dummy data to the ABS 28, the ABS 28 sends a response signal to the network in response to the dummy data. By receiving this response signal, the EFI (registered trademark) 26 becomes the ABS.
It can be recognized that 28 is installed in the vehicle. Similarly, when the 4WD 18 is equipped, the EFI (registered trademark) 26 can confirm its presence by receiving a response signal from the 4WD 18, and the 4WD 18 can detect the ABS.
28 can be recognized, and conversely, ABS 28 can also recognize the presence of 4WD18. Then, when the response signal is received, it is recognized that the option is added, and "with option" is stored in the erasable memory such as the EEPROM. On the other hand, if no response signal is received, "no option" is stored in the EEPROM in the same manner (S
103, S104). The EFI (registered trademark) 26 transmits dummy data to all the ECUs, and repeats the above-described processing to recognize the presence or absence of the option (S105).
The EEPROM is provided with a switch (not shown) for erasing the memory when erroneous data is stored, and the memory is erased by operating the switch.

FIG. 3 shows a timing chart of the dummy data transmission and the response signal reception described above.
From EFI (registered trademark) 26, each ECU, that is, AB
The dummy data is sequentially transmitted to S28, the air suspension 14, and the 4WD18. Upon receiving the dummy data, the ABS 28 sends a response signal to the network. When each ECU recognizes this response signal, it can be known that the vehicle is equipped with ABS. Also, air suspension 1
When the dummy data is transmitted to No. 4, when the response signal for the dummy data is not transmitted from the air suspension, each ECU can know that the vehicle is not equipped with the air suspension. When the dummy data for the 4WD 18 is transmitted and the 4WD 18 transmits a response signal in response to the dummy data, each ECU knows that the 4WD 18 is equipped. The presence or absence of such an option is stored in the erasable memory of each ECU.

In this way, each ECU recognizes the presence or absence of the option and stores the information in the memory, and then each EC
U selects and executes a control program according to the presence or absence of optional equipment. For example, taking the ABS 28 as an example, the control program of the ABS 28 is 4WD18 as described above.
It depends on the presence or absence of. Therefore, ABS28
Is a plurality of (4 in this case
Individual) control programs (software A, software B) are stored, and one of the control programs is selected according to the presence or absence of optional equipment stored in the erasable memory. As a result, it is not necessary to provide a dedicated ECU depending on the presence or absence of optional equipment, and it is possible to deal with it only by executing the control program.

Although the above is the processing at the time of assembling the vehicle, the multiplex communication system for a vehicle of the present invention can be applied to the shipping inspection in the factory and the diagnosis at the time of failure. For example,
Suppose there was a vehicle equipped with ABS, air suspension, and 4WD as options. EF which is an ECU attached to each vehicle by assigning each option system to each bit of binary number
Option E that can communicate with I (registered trademark) as a master
A code is generated by setting the bit corresponding to the CU to 1, and this code is displayed. When ABS, air suspension, and 4WD are all assembled, the code (111) will be displayed. For example, when the air suspension is not assembled, the code (101) will be displayed and extremely Assembly failure can be easily detected. In addition, in the above-mentioned example, it is assumed that there is a vehicle determined to be normally assembled with the code (111) at the time of factory shipment, and communication from 4WD is interrupted due to some abnormality. In this case, if the code is displayed again, it becomes (110) and 4W
Abnormality of D is detected immediately.

Further, in addition to such factory shipping inspection and diagnosis at the time of failure, it is necessary to newly install an ABS dedicated to 4WD even when it is desired by the user to add 4WD as an option from the absence of 4WD. Therefore, the user's wishes can be easily satisfied by selectively executing the control program.

[0015]

As described above, according to the vehicle multiplex communication system of the present invention, it is not necessary to mount a dedicated ECU depending on the presence or absence of optional equipment. Diagnosis can be made extremely easily and efficiently.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an embodiment of the present invention.

FIG. 2 is a processing flowchart of the embodiment.

FIG. 3 is a timing chart of the same embodiment.

FIG. 4 is a system configuration diagram of a conventional system with 4WD.

FIG. 5 is a system configuration diagram of a conventional system without 4WD.

[Explanation of symbols]

 10 ABS (anti-lock brake system) 12 Traction control 14 Air suspension 16 4WS 18 4WD 20 Air conditioner 22 Auto drive 24 ECT (registered trademark) 26 EFI (registered trademark)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H04L 12/40 12/42 8838-5K H04L 11/00 330

Claims (1)

[Claims] 1. A vehicle multiplex communication system for performing data communication between a plurality of electronic control devices mounted on a vehicle, wherein one electronic control device of the plurality of electronic control devices is another electronic control device. At least one of the other electronic control units has a transmitting unit for transmitting dummy data to the control unit, and a response unit for transmitting a response signal according to the dummy data, and a system using the response signal. An identification unit for identifying another electronic control device connected to the control unit, and a selection unit for selecting one control program from a plurality of control programs predetermined according to the identification result by the identification unit. Characteristic vehicle multiplex communication system.