JP3644058B2 - Electronic control device for vehicle engine and data rewrite control device for EEPROM - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an on- board engine electronic control device and an EEPROM data rewrite control device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a system equipped with an EEPROM, for example, an electronic controller for an in-vehicle engine (an ECU for engine control; Electronic Control Unit) equipped with an EEPROM as a non-volatile memory, a technique for accurately storing the data of the EEPROM There is a rewrite. In other words, vehicle number data, destination data, etc. are stored in the EEPROM, but the data in this EEPROM has a limit on the number of rewrites and the data guarantee is about 10 years. It is necessary to rewrite data. Therefore, the CPU, which is a component device of the ECU, rewrites the EEPROM data. As a specific example, a plurality of vehicle number data, which is essentially one for checking data, is prepared in the EEPROM (an odd number is prepared), and the same data (correct) among the plurality of vehicle number data every time the ignition switch is turned on. It is determined whether or not the data is more than a majority (take a majority vote), and if the same data (correct data) in the vehicle number data is less than a majority, the data is rewritten because an error has occurred.
[0003]
[Problems to be solved by the invention]
However, if this is done, it is necessary to prepare a plurality of vehicle number data, which is essentially one, in the EEPROM, and a large data storage area of the EEPROM is used. Further, since a complicated process of taking a majority decision is performed every time the ignition switch is turned on, a software load is applied. Furthermore, there are cases where all of a plurality of data are erased. In this case, there is a problem that even if a majority vote is taken, it cannot be restored.
[0004]
The present invention has been made to solve the above-mentioned problems, and its object is to eliminate the need for an EEPROM data storage area for rewriting data and to perform complicated processing for rewriting. Another object of the present invention is to provide an onboard engine electronic control device and an EEPROM data rewrite control device that can ensure high reliability.
[0005]
[Means for Solving the Problems]
The invention according to claim 1 is an electronic control device for an in- vehicle engine that operates when an ignition switch is turned on and power is supplied from a battery, and is an EEPROM capable of writing and erasing data, a battery change detection means for detecting the replacement of the battery, when it detects Therefore it has been the exchange of batteries in the battery exchange detection means in a case where the ignition switch is turned on, is written in the EEPROM a data reading means for reading the data, again in the case where data is read, the electronic control device of a vehicle-mounted engine and a data writing means for writing the data to the EEPROM and its gist by said data reading means.
[0006]
The invention according to claim 2, wherein the battery exchange detection means in the first aspect of the present invention, the vehicle-mounted engine and detects the replacement of the battery by using the status bits for indicating the operating state of the backup RAM The gist of the electronic control device is as follows.
[0007]
According to a third aspect of the present invention, there is provided a data rewrite control device for an EEPROM which is operated by power supply from a battery, the battery replacement detecting means for detecting the replacement of the battery, and the battery by the battery replacement detecting means. Data reading means for reading data written in the EEPROM based on the exchange of data, data writing means for rewriting the data read by the data reading means to the EEPROM, and possibility of shutting off the power from the battery A power cutoff possibility detecting means for detecting the power, and when there is no possibility of shutting off the power from the battery after battery replacement by the power cutoff possibility detecting means, the data reading means and the data writing means The gist of the data rewriting control device of the EEPROM that performs the rewriting is as follows.
[0008]
According to a fourth aspect of the present invention, the power shutoff possibility detecting means in the third aspect of the invention detects the possibility of power shutoff from the state of an engine driven by power supply from a battery. The gist of the EEPROM data rewrite control device is as follows.
[0009]
According to a fifth aspect of the invention, the engine according to the fourth aspect of the invention is mounted on a vehicle, and the power shut-off possibility detecting means has a vehicle speed of a predetermined value or higher or an engine speed of a predetermined value or higher. The gist of the data rewrite control device of the EEPROM is that it is determined that there is no possibility of shutting off the power supply from the battery when at least one of the above is satisfied.
[0010]
[Action]
According to the first aspect of the present invention, the battery replacement detection means detects battery replacement. Data reading means even after the ignition switch is turned on, reads the data written in the EEPROM when it is detected result that the replacement of the battery has been in the battery change detection means. The data writing means writes the data read by the data reading means to the EEPROM again.
[0011]
In this way, the EEPROM data is rewritten at the battery replacement timing. Therefore, writing the EEPROM data at the appropriate time (overwriting the same value) eliminates the need for the EEPROM data storage area for rewriting data, which has been necessary in the past, and rewriting data such as majority voting. Therefore, high reliability can be ensured without using complicated processing for data and without erasing data.
[0012]
According to the invention described in claim 2, in addition to the operation of the invention described in claim 1, the battery replacement detection means detects the replacement of the battery using the status bit. Therefore, battery replacement can be easily detected without using dedicated battery replacement detection means (for example, a limit switch that is turned on when the battery is removed).
[0013]
According to the third aspect of the present invention, the battery replacement detection means detects battery replacement. The data reading means reads the data written in the EEPROM based on the battery replacement by the battery replacement detecting means. The data writing means writes the data read by the data reading means to the EEPROM again.
In this way, the EEPROM data is rewritten at the battery replacement timing. Therefore, writing the EEPROM data at the appropriate time (overwriting the same value) eliminates the need for the EEPROM data storage area for rewriting data, which has been necessary in the past, and rewriting data such as majority voting. Therefore, high reliability can be ensured without using complicated processing for data and without erasing data.
The power shutoff possibility detecting means detects the possibility of power shutoff from the battery. When there is no possibility of power shutoff from the battery after battery replacement, the data reading means and the data writing means Rewrite the file. Therefore, the data can be reliably rewritten without turning off the power during the data rewriting.
[0014]
According to the invention described in claim 4, in addition to the operation of the invention described in claim 3, the possibility of shutting off the power from the battery is detected from the state of the engine driven by the power supply from the battery. .
[0015]
According to the invention described in claim 5, in addition to the operation of the invention described in claim 4, when the vehicle speed satisfies at least one of a predetermined value or higher and the engine speed satisfies a predetermined value or higher, the power supply from the battery is It is determined that there is no possibility of blocking.
[0016]
【Example】
DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in an onboard engine electronic control device will be described below with reference to the drawings.
[0017]
FIG. 1 shows the configuration of an electronic control unit (hereinafter referred to as ECU) 4 and its peripheral devices. The automobile is equipped with a diesel engine, the diesel engine is provided with a fuel injection pump, high-pressure fuel is supplied from the fuel injection pump to the diesel engine, and the fuel is injected from the injection valve to drive the engine. . The output of the diesel engine is transmitted to the drive wheels of the vehicle, and the drive wheels are rotated. The ECU 4 shown in FIG. 1 controls the fuel injection amount and the fuel injection timing by controlling the fuel injection amount control actuator and the fuel injection timing control actuator provided in the fuel injection pump based on the operating state of the diesel engine. It is like that.
[0018]
This will be described in detail below.
In FIG. 1, a battery 1, an in-vehicle device 2, and an ECU 4 are mounted on a vehicle. The in-vehicle device 2 includes various sensors, a fuel injection amount control actuator, and a fuel injection timing control actuator. The various sensors include a sensor for detecting the operating state of the diesel engine including an engine speed sensor (crank angle sensor) and a vehicle speed sensor. The battery 1 and the in-vehicle device 2 are electrically connected to the ECU 4 via the connector 3, respectively.
[0019]
The ECU 4 includes a power supply circuit 5, a controller 6, an EEPROM 7 in which data can be electrically written and erased, a read-only memory (ROM) 8 in which data such as an engine control program is stored in advance, and a diode 9. I have. The controller 6 further includes a central processing unit (hereinafter referred to as a CPU) 10, a random access memory (RAM) 11 that temporarily stores data such as calculation results of the CPU 10, and an input / output port 12. The RAM 11, the input / output port 12, the EEPROM 7, and the ROM 8 are each connected to the CPU 10 via the bus 13.
[0020]
The EEPROM 7 stores a unique number (vehicle number) for each vehicle that is not updated once written, data related to the destination of the vehicle (destination data), and the like. In this way, the data stored in the EEPROM 7 is not updated for a long time once written. The EEPROM 7 has a limited number of data rewrite guarantees of about 10,000, and the data guarantee period after data rewrite is about 10 years.
[0021]
The RAM 11 includes a backup RAM 14 that stores and holds data in a state where power is supplied. The backup RAM 14 stores learning values for exhaust gas purification, data indicating input / output signal abnormality, and the like. The in-vehicle device 2 is connected to the input / output port 12 via the first terminal 15 of the connector 3.
[0022]
The first power supply line 16 has one end connected to the battery 1 and the other end connected to the power supply circuit 5 of the ECU 4 via the second terminal 17 of the connector 3. The ignition switch 18 is interposed in the middle of the first power line 16 and is turned on / off (opened / closed) by operating an ignition key (not shown). When the ignition switch 18 is turned on (closed) and the voltage (12 volts) from the battery 1 is input to the power supply circuit 5, the power supply circuit 5 converts the input voltage to a predetermined voltage V _DD (for example, 5 _DD ). Volts) are supplied to the CPU 10, RAM 11, EEPROM 7 and ROM 8, respectively. Thereby, ECU4 is started.
[0023]
The second power supply line 19 has one end connected to the battery 1 and the other end connected to the power supply circuit 5 via the third terminal 20 of the connector 3. The voltage from the battery 1 is constantly supplied to the power supply circuit 5, and the power supply circuit 5 always supplies the input voltage to the backup RAM 14 with a predetermined voltage V _STBY . With this configuration, the backup RAM 14 can always store and hold data regardless of whether the ignition switch 18 is on or off.
[0024]
Hereinafter, the output voltage V _STBY for holding data in the backup RAM 14 is referred to as a standby voltage V _STBY, and the standby voltage V _STBY is substantially the same level as the voltage V _DD output to the CPU 10 or the like.
[0025]
The diode 9 is connected between the output of the power supply circuit 5 to the CPU 10 and the like and the output to the backup RAM 14 and is arranged in the forward direction from the output side to the CPU 10 and the like to the output side to the backup RAM 14. When the level of the standby voltage V _STBY to back up RAM14 is lower than the level of the output voltage V _DD to the CPU10 or the like, outputs the output voltage V _DD to the backup RAM14 through the diode 9 as a standby voltage V _STBY Is done.
[0026]
When the ignition switch 18 is turned on and the operation of the diesel engine is started, the CPU 10 detects the operation state of the diesel engine with a sensor for detecting the operation state of the diesel engine of the in-vehicle device 2 and the data in the backup RAM 14. Is used to control the fuel injection amount and the fuel injection timing by controlling the fuel injection amount control actuator and the fuel injection timing control actuator of the in-vehicle device 2 in accordance with the operating state of the diesel engine. Further, the CPU 10 learns constants for exhaust gas purification during engine control and stores the learned values in the backup RAM 14. Further, the CPU 10 checks the input / output signals, and stores data indicating the abnormality in the backup RAM 14 when an abnormality occurs.
[0027]
In this embodiment, the CPU 10 detects the interruption of the backup power source including the replacement of the battery 1. In other words, the CPU 10 has a status bit for indicating the operation state of the peripheral device. This status bit is “1” in terms of hardware when the standby voltage V _STBY to the backup RAM 14 falls below the reference level for a predetermined time. → "0". Hereinafter, a status bit for indicating the state of the standby voltage V _STBY is referred to as a standby bit.
[0028]
For example, when the battery 1 is temporarily removed for replacement, the second power supply line 19 is disconnected, or the third terminal 20 is poorly contacted, the standby voltage V _STBY to the backup RAM 14 is increased. Becomes equal to or lower than the reference level for a predetermined time, the standby bit of the CPU 10 is changed from “1 → 0”. Therefore, in this state, when the ignition switch 18 is turned on and the ECU 4 is activated, the CPU 10 determines whether or not the battery from the second power supply line 19 including battery replacement is changed based on the change of the standby bit “1 → 0”. Detects that the power supply is cut off.
[0029]
When the CPU 10 detects that the backup power supply is shut off when the ignition switch 18 is turned on, the CPU 10 clears all data in the backup RAM 14.
[0030]
This standby bit holds the state of “0” unless “1” is written by software.
In this embodiment, the data in the EEPROM 7 is rewritten using this standby bit. Details of the data rewriting process (refresh process) of the EEPROM 7 will be described later.
[0031]
In this embodiment, the CPU 10 constitutes a battery replacement detection unit, a data reading unit, a data writing unit, and a power cutoff possibility detection unit.
Next, the operation of the on-vehicle engine electronic control device (EEPROM data rewrite control device) configured as described above will be described.
[0032]
2 shows a flowchart for data rewrite control of the EEPROM 7, and FIG. 3 shows a timing chart. 2 is, for example, every 32 ms or every input of a pulse signal from the crank angle sensor (every predetermined crank angle).
[0033]
In FIG. 3, the ignition switch 18 is turned on at the timing t1, and then the ignition switch 18 is turned off at the timing t2. In this state, the battery 1 is removed at the timing t3, and at the timing t4. It is assumed that a new battery 1 is attached. The replacement of the battery 1 is always performed once or twice in 10 years. Furthermore, it is assumed that the ignition switch 18 is turned on at timing t5. In FIG. 3, with the standby voltage V _STBY by removal of the battery 1 at t3 becomes the L level CPU10 standby bit is "0", the standby voltage V _STBY by mounting of the battery 1 at the timing of subsequent t4 Returns to H level.
[0034]
In FIG. 2, the CPU 10 determines in step 100 whether or not the vehicle speed is 50 Km / h or more and the engine speed is 2000 rpm or more based on a signal from the vehicle speed sensor and a signal from the engine speed sensor (crank angle sensor). judge. This process is for detecting the possibility of interruption of the power supply from the battery 1, and detects the state of the diesel engine driven by the power supply from the battery 1 based on the vehicle speed and the engine speed. The possibility of shutting off the power from the battery 1 is detected by detecting the state of the diesel engine. Then, if the vehicle speed is 50 Km / h or more and the engine speed is not 2000 rpm or more, the CPU 10 determines that there is a possibility that the power from the battery 1 may be shut off (t5 to t6 in FIG. 3). Period).
[0035]
On the other hand, if the vehicle speed is 50 km / h or more and the engine speed is 2000 rpm or more (timing at t6 in FIG. 3), the CPU 10 determines that there is no possibility of shutting off the power from the battery 1 and proceeds to step 101. Then, it is determined whether or not the state of the standby bit is “1”. When the CPU 10 is “1”, the CPU 10 determines that the battery 1 has not been replaced. That is, when the battery 1 is not removed, the level of the standby voltage V _STBY does not decrease, so the standby bit is held in the “1” state. Therefore, in such a case, the CPU 10 determines that the battery 1 has not been replaced, and ends the routine.
[0036]
On the other hand, if the state of the standby bit is not “1” in step 101, that is, if it is changed from “1 → 0”, the CPU 10 determines that the battery 1 has been replaced.
[0037]
That is, when the battery 1 is removed, the standby voltage V _STBY falls below the reference level for a predetermined time, and the standby bit of the CPU 10 is changed from “1 → 0”. Therefore, in such a case, it is determined that the battery 1 has been replaced, and the routine proceeds to step 102.
[0038]
In step 102, the CPU 10 reads the contents (data written) of the EEPROM 7 and proceeds to step 103. In step 103, the CPU 10 rewrites the read data contents in the EEPROM 7. Furthermore, the CPU 10 sets the standby bit to “1” in step 104 (standby bit rising operation at t6 in FIG. 3).
[0039]
In this manner, data rewriting of the EEPROM 7 is performed when a predetermined condition is satisfied after battery replacement (the vehicle speed is 50 Km / h or more and the engine speed is 2000 rpm or more).
[0040]
Even when the second power supply line 19 is disconnected or a contact failure occurs in the third terminal 20, the level of the standby voltage V _STBY decreases and the standby bit becomes “ 1 → 0 ”. Accordingly, when the ignition switch 18 is subsequently turned on, the data in the EEPROM 7 is rewritten. However, even in such a case, it is unlikely that the limit of 10,000 times of writing in the EEPROM 7 will be exceeded, and there will be no trouble.
[0041]
As described above, in this embodiment, the CPU 10 detects the replacement of the battery 1 in the process of step 101 in FIG. 2 and reads the data written in the EEPROM 7 in the process of step 102 based on the replacement of the battery 1. The data read out in step 103 is written into the EEPROM 7 again. Therefore, the data in the EEPROM 7 is rewritten at the battery replacement timing. That is, in order to retain the data in the EEPROM 7, it is necessary to rewrite it once or twice in 10 years, and the data in the EEPROM 7 is rewritten at a battery replacement timing that is always performed at least once or twice in 10 years. As a result, by writing the data in the EEPROM 7 at an appropriate time (overwriting the same value), the data storage area of the EEPROM for rewriting the data which has been necessary in the past becomes unnecessary, and the data such as majority decision is rewritten. High reliability is ensured without using complicated processing for writing and without erasing data. In this way, the data in the EEPROM 7 can be stored accurately and semi-permanently.
[0042]
Further, since the CPU 10 detects the replacement of the battery 1 using the standby bit in the process of step 101 in FIG. 2, dedicated battery replacement detection means (for example, a limit switch that is turned on when the battery is removed). Without using the battery, it is possible to easily detect the replacement of the battery, simplify the configuration, and reduce the manufacturing cost.
[0043]
Furthermore, the CPU 10 detects the possibility of the power supply from the battery 1 being cut off after the battery is replaced in the process of step 100 in FIG. In the state of the diesel engine driven by the power supply of (when the vehicle speed is equal to or higher than the predetermined value and the engine speed is equal to or higher than the predetermined value), the data is rewritten. Therefore, it is impossible for the power to be cut off when the vehicle speed is equal to or higher than the predetermined value and the engine speed is higher than the predetermined value. Therefore, sufficient writing time can be secured and the power is shut off during data rewriting. Therefore, it is possible to reliably rewrite data.
[0044]
As another aspect of the present invention, in step 100 of FIG. 2, the detection of the possibility of shutting off the power from the battery 1 is detected from the battery when the vehicle speed satisfies a predetermined value or higher or the engine speed satisfies a predetermined value or higher. It may be determined that there is no possibility of shutting off the power source.
[0045]
The present invention can be embodied in various devices other than the engine control ECU.
[0046]
【The invention's effect】
As described above in detail, according to the invention described in claim 1, the data storage area of the EEPROM for rewriting data can be made unnecessary , without performing complicated processing for rewriting, and Demonstrate the excellent effect of ensuring high reliability.
In addition, since the data is rewritten when the ignition switch is turned on, the data can be reliably rewritten without shutting off the power in the middle of the data rewriting.
[0047]
According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, it is possible to easily detect the replacement of the battery without using a dedicated battery replacement detection means.
[0048]
According to the invention described in claim 3, 4, 5, without any power is cut off in the middle of rewriting data, it is possible to perform the rewriting of data reliably.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an on-vehicle engine electronic control device and its peripheral devices.
FIG. 2 is a flowchart for explaining the operation.
FIG. 3 is a timing chart for explaining the operation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Battery, 7 ... EEPROM, 10 ... Battery exchange detection means, Data reading means, Data writing means, CPU which comprises a power interruption possibility detection means, 14 ... Backup RAM.

Claims (5)

An electronic control device for an in- vehicle engine that operates when an ignition switch is turned on and power is supplied from a battery,
EEPROM capable of writing and erasing data;
Battery replacement detection means for detecting replacement of the battery;
When it detects Therefore the replacement of the battery has been in the battery replacement detection means in a case where the ignition switch is turned on, a data reading means for reading the data written in said EEPROM,
An electronic control apparatus for an on- vehicle engine , comprising: a data writing means for writing the data to an EEPROM again when data is read by the data reading means. The on- board engine electronic control device according to claim 1, wherein the battery replacement detection means detects a battery replacement by using a status bit for indicating an operation state of the backup RAM. An EEPROM data rewrite control device that operates by power supply from a battery,
Battery replacement detection means for detecting replacement of the battery;
Data reading means for reading data written in the EEPROM based on battery replacement by the battery replacement detecting means;
Data writing means for writing the data read by the data reading means to the EEPROM again;
A power-off possibility detection means for detecting the possibility of power-off from the battery;
The provided, when there is no possibility of interruption of power supply from the battery after the battery replacement by the power-off potential detection means, said data reading means and the data writing means and the data line cormorants E EPROM rewriting data Rewrite control device.   4. The EEPROM data rewrite control device according to claim 3, wherein the power cutoff possibility detecting means detects the possibility of power cutoff from the state of an engine driven by power supply from a battery.   The engine is mounted on a vehicle, and the power cut-off possibility detecting means can cut off the power from the battery when the vehicle speed satisfies at least one of a predetermined value and the engine speed meets a predetermined value or more. 5. The EEPROM data rewrite control device according to claim 4, wherein the data rewrite control device is determined to be non-existent.

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