JPH1082342A - Vehicular controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly prevent such a state that a part of control data is lost when the control data are memorized from a CPU to a non-volatile memory when an ignition switch is switched off, by prohibiting the writing of the control, data in case that the memory operating time of the memory is longer than condenser discharging time. SOLUTION: In the case that it is discriminated that control data need be memorized when an ignition switch 13 is switched off, the terminal voltage value Vx of a condenser 17 is measured, and it is discriminated whether or not this voltage value Vx is larger than a regulated value, that is, the memory operating time T1 of an E<2> PROM 16. Then, the control data are memorized in the E<2> PROM 16 only when a condition of T1 <CVx /I the capacity of the condenser 17, I: internal current in a circuit) is set up. However, in case that this condition does not set up, the control data are returned as they are without written. Hereby, such a situation can be prevented that a part of the control data in the E<2> PROM 16 is lost by a deficiency of the discharge time of the condenser 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a control device for an automobile engine, and in particular, stores control information (control data) which is inconvenient to be erased during engine control by a nonvolatile memory after an ignition switch is turned off. The present invention relates to a control device for a vehicle.

[0002]

2. Description of the Related Art In recent years, in automobiles, a configuration in which fuel injection and ignition timing of an engine, ABS, and the like are performed by a computer (CPU) has been widely adopted. Such control requires various control data, and at least a part of the control data is required when the engine is driven or started. For this reason, it is necessary to store this type of control data in the non-volatile memory when the operation of the engine is completed or when the ignition switch is turned off.

For example, Japanese Patent Application Laid-Open No. 55-138104 discloses
An engine control device disclosed in Japanese Unexamined Patent Application Publication No. 2005-163,813 is provided. Referring to FIG. 4, an outline is shown, in which a reference numeral 1 designates a memory (RAM) which can be freely written and read, and which stores and updates control data during normal running. Also,
Numeral 2 denotes an EAROM provided corresponding to the RAM 1. The EAROM 2 is a non-volatile memory that saves at least important data that the user does not want to erase out of the stored contents of the RAM 1 when the ignition switch 3 is turned off. Has become. When the ignition switch 3 is turned on, the control data saved in the EAROM 2 is returned to the RAM 1 again.

For this reason, when the power of the battery 4 is turned off by the ignition switch 3, the contents stored in the RAM 1 are saved in the EAROM 2. A signal is input to the EAROM 2. That is, the power of the battery 4 is input to the monostable multivibrator 5 via the ignition switch 3 and the inverter 6, and the inverter 7 outputs the inverted output to the monostable multivibrator 5 in conjunction with the turning off of the ignition switch 3. , Which outputs a write command signal.

A read command signal is input to the RAM 1 from the monostable multivibrator 7 in response to the turning on of the ignition switch 3, and the contents stored in the EAROM 2 are returned to the RAM 1. That is, the power of the battery 4 is supplied to the monostable multivibrator 7 via the ignition switch 3 and the buffer amplifier 8, and when the ignition switch 3 is turned on, the monostable multivibrator 7 outputs a read command signal.

The power for driving the inverter 7 and the EAROM 2 is supplied from a capacitor 9.
Is turned on, the power of the battery 4 is supplied to the capacitor 9 via the diode 10, and the capacitor 9 is charged.

With this configuration, control data updated based on a predetermined flow can be saved in the EAROM 2, so that data required for engine control can always be supplied.

[0008]

By the way, the EAR
When the ignition switch 3 is turned off, the OM 2 is driven by the power supplied from the capacitor 9. The EAROM 2 takes a normal RAM time from the start of storage to the end of storage.
It takes longer than one. Therefore, depending on the control data, the time required for the EAROM 2 to store the control data (storage operation time) may be shorter than the voltage capacity of the capacitor 9, that is, the discharge time is shorter than the storage operation time of the EAROM 2. As a result, the writing operation in the EAROM 2 is controlled by the discharge time from the capacitor 9, and in some cases, a part of the control data stored in the EAROM 2 may be lost. Control data may be discarded.

[0009]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned conventional problems.
A volatile memory and a nonvolatile memory for storing various information for vehicle control, and a CPU for controlling writing and reading in the volatile memory and the nonvolatile memory;
A power supply circuit for supplying power to the CPU, an ignition switch connected between the power supply circuit and the battery, and a power supply circuit between the ignition switch and the CPU for supplying power to the nonvolatile memory; A capacitor, and after turning off an ignition switch, the CPU operates a storage operation time from the start of storage for storing various types of information of the engine to the nonvolatile memory to the completion of storage, and the storage capacity of the nonvolatile memory based on the voltage capacity of the capacitor. It is characterized by including a control circuit that compares the storable time with the storage time, and when the storable time is shorter than the storage operation time, does not perform the storage operation by the nonvolatile memory.

According to a second aspect of the present invention, in the control circuit, it is determined whether or not the current voltage capacity of the capacitor is equal to or greater than a specified capacity, and if not, the storable time is shorter than the storage operation time. The storage operation by the nonvolatile memory is not performed.

According to a third aspect of the present invention, the control circuit compares a storable time of the non-volatile memory based on a voltage capacity of a capacitor with a storage operation time of all data by the non-volatile memory, and If shorter than the entire data storage operation time, the storage operation of all data is not performed, and the storable time is compared with the partial data storage operation time, and the storable time is shorter than the partial data storage operation time. The storage operation of the partial data by the nonvolatile memory is performed only when the data is long.

According to such a configuration, when control data is stored (written) from the CPU to the non-volatile memory after the ignition switch is turned off, the storage operation time of the non-volatile memory and the capacity of the capacitor are controlled by the CPU. Comparing the discharge times, if the storage operation time of the nonvolatile memory is longer than the capacitor discharge time, the storage operation of the control data, that is, the writing of the control data is not performed.

According to the third aspect of the present invention, the storage capacity of the nonvolatile memory, that is, the write capacity is selected based on the current voltage capacity value of the capacitor, so that the control device for the vehicle operates normally. Necessary data can be accurately stored and saved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a vehicle control device according to the present invention is applied to a vehicle engine control device will be described below with reference to the drawings.

FIG. 1 is a block diagram of a control system of an engine control device according to this embodiment.
2, a battery for supplying current to 2, an ignition switch 13, a CPU 14, and a volatile memory (RA) 15.
M) and 16 are nonvolatile memories (E ² PROM) for storing data such as control constants, and 17 is a smoothing capacitor.

The ignition switch 13
Is turned on, the capacitor 17 is charged via the diode 18, and when the charge is accumulated in the capacitor 17 for a certain amount or more and becomes a specified voltage or more, the regulator (REG) 23 serving as a counter is used to control the CPU 14 and E. ² P
ROM16, RAM15, A / D (analog digital)
It is applied to the converter 19 and the ROM 20.

The RAM 15 is a volatile memory that can be freely written and read, and stores and updates control data during normal running of the vehicle. The E ² PROM1
6 indicates a capacitor 17 when the battery 11 is turned off.
At least the vehicle control data that the user does not want to erase out of the contents stored in the RAM 15 is saved by the voltage of the RAM 15. When the battery 11 power is turned on, the RAM 15 stores the control information saved in the E ² PROM 16 via the CPU 14. The data is returned again. The A / D converter 19 is an element that digitizes the terminal voltage at the point 17 a of the capacitor 17 via the interface circuit 21 and sends this voltage information signal to the CPU 14. The ROM 20 is a non-volatile memory for storing a control program and fixed data.

The CPU 14 performs digital arithmetic processing and outputs the result to the output circuit 22 based on the contents of the E ² PROM 16 and the ROM 20, and internally stores control data for the E ² PROM 16. Is provided with a control circuit for determining whether or not it is necessary. That is, when executing an instruction to be stored in the E ² PROM 16, the terminal voltage value V _X of the point 17a of the capacitor 17 is measured by the A / D converter 19 through the interface circuit 21, the voltage information signal is transferred to the CPU14 You.

In the control circuit, when the ignition switch 13 is turned off, the terminal voltage V _X
In accordance with comparison of the storage operation time T ₁ of the storable time and E ² PROM 16 control data E ² PROM16, T ₁ is adapted to perform a store operation by the E ² PROM 16 only if less than the storage available time . Specifically, it is determined whether or not the storable time is longer than the storage operation time based on whether or not the current voltage capacity of the capacitor 17 is equal to or greater than the specified voltage capacity.

That is, as shown in the flowchart of FIG. 2, when the ignition switch 13 is turned off, it is determined in step 1 whether or not it is necessary to store control data. If it is not necessary to store the information, the process directly returns. If it is determined that the information needs to be stored, the process proceeds to step S2. Here, measures the terminal voltage value V _X of the capacitor 17, the next step 3, the memory operation time of the voltage value V _X is the specified value, i.e. E ² PROM 16 T ₁
Determine if it is greater than.

Only when the condition of T ₁ <CV _X / I (C: capacity of the capacitor 17, I: circuit internal current) is satisfied, the process proceeds to step 4, where the control data is stored in the E ² PROM 16. Suruga, if the condition is not satisfied in the step 2, that is, if CV _X / I is less than T ₁ is directly returned without writing control data.

Therefore, in the engine control by the E ² PROM 16, not only can the required data be maintained, but also the E ² PR due to the short discharge time of the capacitor 17.
A situation in which a part of the control data in the OM 16 is lost is reliably prevented. FIG. 3 shows a second embodiment of the present invention, in which the storage operation of the nonvolatile memory 16 by the control circuit is slightly modified. That is, when the ignition switch 13 is turned off, it is determined in step 5 whether or not the control data needs to be stored. If not, the process returns as it is, but it is determined that the storage is necessary. In this case, the process proceeds to step 6. In step 6, to measure the current terminal 17a the voltage value V _X of the capacitor 17. Then control proceeds to step 7, the voltage value V _X all data storage operation time in the nonvolatile memory 16 (write operation time) to determine whether greater or not than the guarantee voltage value V _X1. If it is determined that the data is large, all data is written and stored in step 8 as it is.
That is, assuming that the total data storage operation time T ₂ , circuit current I, capacitor capacitance C, and current capacitor voltage value V _X , when the condition of T ₂ <CV _X / I to V _X > C / T ₂ I is satisfied. The writing of all data is allowed to be performed.

Further, when it is determined that V _X is small in step 7, the process proceeds to step 9. This step 9
In turn discriminates whether the voltage value V _X is greater than some data storage operation time (write operation time) guarantee voltage value V _X2 of the nonvolatile memory 16. Here, if it is determined that a small, but not write operation of the data and return it, if it is determined that a large voltage value V _X, the process proceeds to step 10, where the non-volatile memory 16 is a part For example, the minimum data is written and stored.
That is, assuming that the partial data write operation time T ₃ and the current capacitor voltage value V _X , T ₃ <CV _X / I to V _X > C
When the condition of / T ₃ I is satisfied, writing of the minimum data is permitted.

[0024] Therefore, according to the second embodiment, while by selecting the writing capacity of the nonvolatile memory 16 by the voltage capacitance value V _X of the current of the capacitor 17, the vehicle control device is operating normally It is possible to accurately store and save a part of data necessary for the data.

[0025]

As is apparent from the above description, according to the vehicular control apparatus of the present invention, control data required for vehicle control can be stored and maintained by a non-volatile memory as in the prior art. It is possible to reliably prevent a part of the control data from being lost during the storage operation of the nonvolatile memory due to a short discharge time of the capacitor. As a result, it is possible to avoid that all control data stored in the nonvolatile memory in advance is discarded.

According to the third aspect of the present invention, the write capacity of the nonvolatile memory is selected according to the current voltage capacity value of the capacitor, so that the write capacity required during normal operation of the vehicle control device is obtained. Some data can be stored and saved accurately.

[Brief description of the drawings]

FIG. 1 is a block diagram of an engine control system according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a process when the CPU according to the embodiment determines that an ignition switch is turned off.

FIG. 3 is a flowchart showing a second embodiment of the present invention.

FIG. 4 is a block diagram of a control system provided to a conventional engine control device.

[Explanation of symbols]

11 ... Battery 13 ... ignition switch 14 ... CPU 15 ... volatile memory (RAM) 16 ... nonvolatile memory (E ² PROM) 17 ... capacitor

Claims (3)

[Claims] 1. A volatile memory and a nonvolatile memory for storing various information for controlling a vehicle, a CPU for controlling writing and reading in the volatile memory and the nonvolatile memory, and a power supply circuit for supplying power to the CPU And an ignition switch connected between the power supply circuit and a battery; and a capacitor connected to a power supply circuit between the ignition switch and a CPU to energize the nonvolatile memory. After turning off the ignition switch, a comparison is made between the storage operation time from the start of storage for storing various types of vehicle control information in the nonvolatile memory to the completion of storage and the storable time of the nonvolatile memory based on the voltage capacity of the capacitor. If the storable time is shorter than the storage operation time, a non-volatile memory is used. Vehicle control apparatus characterized by comprising a control circuit which does not perform the storage operation. 2. The non-volatile memory according to claim 1, wherein the control circuit determines whether the current voltage capacity of the capacitor is equal to or greater than a specified capacity. 2. The vehicle control device according to claim 1, wherein the storage operation is not performed. 3. The control circuit compares a storable time of a non-volatile memory based on a voltage capacity of a capacitor with a storage operation time of all data by the non-volatile memory. Is too short,
The storage operation of all data is not performed, and the storable time is compared with the partial data storage operation time. Only when the storable time is longer than the partial data storage operation time, the non-volatile memory stores the partial data. 2. The vehicle control device according to claim 1, wherein the storage operation is performed.