JP3496484B2 - Memory rewriting device for vehicle control - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a memory rewriting device for a control unit mounted on a vehicle.

[0002]

2. Description of the Related Art In a control unit composed of a CPU, a memory and an input / output device, it has conventionally been necessary to replace the memory itself in order to change the contents of the control memory. By using an erasable and writable memory, it is not necessary to replace the control memory and the cost can be reduced (see Japanese Patent Laid-Open No. 7-287605).

[0003]

By the way, the function as the control unit stops during the rewriting of the control memory, but since the control memory is in the power supply state (the ignition key switch is in the ON state) for rewriting, There is a possibility that another control unit connected via the communication device to the control unit in which the control memory is rewritten will malfunction.

For example, two control units for engine control and automatic transmission control are communicated at a constant cycle (for example, LAN communication, CAN).
In the control unit for automatic transmission control,
Since self-diagnosis is performed as to whether or not communication is normally performed with the engine control unit (it exchanges a predetermined signal, and when no signal is returned, it is determined that the communication device has a failure). During the rewriting of the control memory in the engine control unit, it becomes impossible to communicate with the engine control unit, so the automatic transmission control unit erroneously determined that there was a communication failure. It ends up.

[0005]

[0006]

[0007]

[0008]

SUMMARY OF THE INVENTION A first invention is a control unit equipped with a control memory composed of a memory that can be electrically erased and written by an external tool, and permission of data rewriting from the external tool to the control memory. In a vehicle control memory rewriting device, which is provided with a means for making a judgment, and in which data rewriting to a control memory is executed only when rewriting is permitted, a control unit for rewriting the control memory is connected via a communication device. When there is another control unit, a means for suspending communication with the control unit being rewritten while the control memory is being rewritten is provided.

In the second invention, the control unit for rewriting the control memory in the first invention is the control unit for engine control, the other control unit is the control unit for automatic transmission control, and the control memory is rewritten. During the suspension of communication, the control unit for engine control continues to send a communication prohibition signal to the control unit for automatic transmission control, and while this communication prohibition signal is being received, the self-control of the communication device by the control unit for automatic transmission control is continued. It is to stop the diagnosis.

In the third invention, the control in the first invention is carried out.
To cancel the communication while rewriting the memory, write the control memory.
From the control unit where the replacement is performed,
Keep sending the communication prohibition signal to the control unit
While receiving the communication prohibition signal, the other control
Stop self-diagnosis of communication device by unit
That is.

[0011]

According to the first aspect of the present invention, when there is another control unit connected to the control unit for rewriting the control memory via the communication device, communication of the control unit being rewritten during rewriting of the control memory. Stop the other control unit.
The unit is a controller where the control memory is rewritten.
There is no misjudgment that the
Thus, the malfunction of the other control unit during rewriting of the control memory can be avoided.

According to the second aspect, the automatic transmission control unit does not erroneously determine that the communication device on the engine control unit side has a failure.

According to the third invention , another control unit is provided.
Knit is a control whose control memory is rewritten
It is possible to erroneously determine that the communication device on the unit side is defective.
Absent.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a system configuration, and 1 is an engine control unit (hereinafter referred to as ECM).

In the ECM 1 including a CPU, a memory and an input / output device, the CPU performs various controls according to a control program. For example, as a mechanism to automatically control the idle speed to a target value according to operating conditions, in the auxiliary air passage that bypasses the throttle valve,
An auxiliary air valve driven by a signal from the ECM1 is interposed, and the opening degree of the auxiliary air valve is controlled by a step motor,
The idle speed is controlled to match the target value.

By configuring the control memory with a flash memory (electrically erasable and writable memory), a bug (mistake) is found in the idle speed control program after the control program is written in the flash memory. , The ECM as shown in FIG.
It is possible to connect the external tool 2 to 1 and send the rewriting data of the control memory from the external tool 2 to rewrite the control memory inside the ECM 1.

Like the ECM 1, the external tool 2 for rewriting the control memory is also composed of a CPU, a memory and an input / output device, and has control memory rewriting data (a control program after eliminating bugs) mounted therein. External tool 2
Is connected to the ECM 1 via a communication line when the control memory is rewritten, and the control memory is rewritten as shown in FIG. Both the ECM 1 and the external tool 2 have a communication device, and both exchange data by serial communication.

This control memory can be rewritten without removing the ECM 1 from the vehicle, with the engine stopped,
Perform with the engine key switch turned on.

FIG. 2 is a communication sequence showing the exchange of signals between the external tool 2 and the ECM 1.

When rewriting the control memory, first the EC
Security communication is performed with M1. Security communication is an exchange of ciphers before rewriting the memory so that it cannot be easily rewritten in the market by any person other than the manufacturer or dealer related person, including the control memory. . Specifically, the external tool 2 sends a rewrite prevention cancellation request to the ECM1, and if this is a legitimate request, the ECM1 that has received the request.
By sending back the rewrite protection release, the security communication ends, and the ECM 1 enters the unlocked state (that is, the rewrite protection released state).

If the external tool is not a legitimate external tool, the ECM 1 does not enter the unlocked state and remains in the locked state (rewrite prevention state) because the encryption is not exchanged.

When the security communication is completed, the external tool 2 continuously sends a rewriting request of the control memory to the ECM 1. In response to the request from the external tool 2, the ECM 1 performs the processing when receiving the control memory rewrite request. This receiving process and the receiving process of control memory rewriting permission by the external tool 2 which will be described later are detailed in Japanese Patent Application No. 9-49061, but are omitted since they are not directly related to the present invention.
When the process for receiving the control memory rewrite request is completed, enter E
A control memory rewrite permission is transmitted to CM1.

In response to this transmission, the external tool 2 performs the processing at the time of receiving the control memory rewriting permission. After completing the process when receiving the control memory rewrite permission by the external tool,
The control memory rewrite data is sent to ECM1. ECM1
Then, when the control memory rewriting data is received, the control memory is rewritten. As for idle speed control,
By this rewriting, the entire control program after the error is corrected is stored in the control memory of the ECM 1.

When the rewriting is completed, the unlocked state is switched to the locked state, and the completion of the rewriting is sent back to the external tool 2. The external tool 2 receives this transmission and confirms that the rewriting of the control memory is completed.

By the way, while the function as the control unit is stopped during the rewriting of the control memory for the ECM 1, the control memory is in the power supply state (the ignition key switch is in the ON state) for rewriting, so the control memory There is a possibility that the control unit for automatic transmission control, which is connected to the ECM 1 in which the rewriting is performed via the communication device, malfunctions.

In order to deal with this, in the first embodiment of the present invention, the ECM 1 is rewriting the control memory during the rewriting of the ECM.
Communication with 1 is stopped.

The contents of this control will be described with reference to the following flow chart.

First, FIG. 3 shows processing on the ECM 1 side.

At step 1, whether or not it is the communication timing is determined. When it is at that timing, the process proceeds to step 2 to see if the rewriting of the control memory is completed. Before the rewriting is completed, the process proceeds to steps 3 and 4, where a communication prohibition signal is transmitted to the automatic transmission control unit and the control memory is rewritten.

As a result, when the rewriting is completed, the process proceeds from step 2 to step 5 and a signal for releasing the communication inhibition is transmitted to the automatic transmission control unit.

On the other hand, when it is not the communication timing, the process proceeds to steps 6 and 7, and as in the conventional case, it is checked whether the rewriting is completed, and if it is not completed, the control memory is rewritten.

Next, FIG. 4 shows processing on the side of the control unit for automatic transmission control.

In step 11, it is determined whether or not the communication prohibition signal from the ECM 1 is received. If not, the process proceeds to steps 12 and 13, where self-diagnosis of communication is performed as in the conventional case and the automatic transmission (in the figure, (Abbreviated as AT) is performed normally.

On the other hand, when the communication prohibition signal is received, the routine proceeds from step 11 to step 14 where the self-diagnosis for communication is stopped and then the processing of step 13 is executed.

As described above, in the first embodiment, the ECM1
While the control memory is being rewritten, the ECM1 continues to send a communication prohibition signal to the automatic transmission control unit, and while the communication prohibition signal is being received, the automatic transmission control unit performs self-diagnosis of the communication device. Since the operation is stopped, the automatic transmission control unit does not erroneously determine that the communication device on the ECM 1 side has a failure.

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

In the first embodiment, the case where the other control unit that communicates with the ECM1 is the control unit for automatic transmission control has been described, but the present invention is not limited to this, and another control unit that communicates with the ECM1 is described. However, the present invention is also applicable to, for example, a control unit for TCS (traction control system) control or a control unit for ASCD (constant speed traveling device) control.

[0046]

[0047] Further, in the embodiment, the rewriting of the control memory is performed has been described in the case of E CM1,
Not limited to this, the control memory is rewritten to E
It goes without saying that the present invention is also applicable to a control unit other than CM1.

[Brief description of drawings]

FIG. 1 is a control system diagram of a first embodiment.

FIG. 2 is a communication sequence diagram of the first embodiment.

FIG. 3 is a flowchart for explaining processing on the ECM1 side.

FIG. 4 is a flowchart for explaining processing on the control unit side for automatic transmission control.

[Explanation of symbols]

1 ECM 2 External tools

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Claims (3)

(57) [Claims] 1. A control unit equipped with a control memory composed of a memory that can be electrically erased and written by an external tool, and means for determining permission of data rewriting from the external tool to the control memory.
In the vehicle control memory rewriting device in which the data rewriting to the control memory is executed only when the rewriting is permitted, when the control unit for rewriting the control memory and another control unit connected via the communication device are present. During the rewriting of the control memory, a vehicle control memory rewriting device comprising means for stopping communication with the control unit during the rewriting. 2. The control unit for rewriting the control memory is an engine control control unit, and the other control unit is an automatic transmission control control unit,
If the communication is stopped while the control memory is being rewritten, the control unit for engine control continues to send a communication prohibition signal to the control unit for automatic transmission control, and while the communication prohibition signal is received, communication by the control unit for automatic transmission control The vehicle control memory rewriting device according to claim 1, wherein the self-diagnosis of the device is stopped. 3. Canceling communication during rewriting of the control memory,
The control unit in which the control memory is rewritten
Signal to the other control unit from the communication
, And while receiving this communication prohibition signal,
Self about communication device by other control unit
2. The self-diagnosis is to be stopped.
The vehicle control memory rewriting device according to.