JPH0531251Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Field of Industrial Application) The present invention relates to an engine control information storage device suitable for application to various learning control devices for internal combustion engines such as automobiles, such as air-fuel ratio learning control devices, and in particular, to This invention relates to a device that is easy to set up. (Prior Art) In recent years, with the development of electronic devices, it has become possible to achieve contradictory issues such as engine output, fuel efficiency, and exhaust emissions at a high level by performing feedback control using microcomputers. In addition, there is learning control as a control mode that applies feedback control.Learning control stores the feedback control amount in memory according to the engine operating condition, and when the same operating condition is reached thereafter, the feedback control amount is used based on the stored feedback control amount. Control responsiveness and control accuracy are improved through control. In this case, since the memory used for learning control needs to retain the stored data even after the engine is stopped,
An engine control information storage device whose memory contents can be backed up has been proposed (SAE paper).
860594). As a conventional engine control information storage device of this type, there is, for example, a first one as shown in FIG. In the figure, 1 is a C-MOS configuration.
A voltage V _B from a battery (not shown) is stabilized by a voltage regulator diode 2 and a voltage V _D is supplied to the RAM 1 . That is,
A voltage V _D is constantly applied to RAM1 to back up the memory contents. Also, when erasing the memory contents, disconnect the battery terminal and stop supplying the voltage _VD . In addition, 4 is the RAM when the voltage V _D is momentarily interrupted.
1 is a capacitor that supplies power, and 3 is a resistor that supplies current for the constant voltage diode 2 to exhibit a constant voltage effect. (Problem to be solved by the invention) However, in such a conventional engine control information storage device, since the capacitor 4 is provided in parallel with the power supply terminal of the RAM 1, it is particularly difficult to erase the memory contents. The following problems occurred. That is, although the current consumption of RAM1 is extremely small, there are relatively large variations in its value. Further, when the battery terminal is disconnected, the voltage V _D does not become zero immediately because the capacitor 4 is charged, but gradually decreases due to the current consumption of the RAM 1. Therefore, it takes about 3 hours to 1 day for the voltage V _D to drop and the memory contents of the RAM 1 to be erased, resulting in poor workability. Therefore, in order to solve this problem, a second method has been considered in which a resistor 5 is provided in parallel with the capacitor 4, as shown in FIG. 5, for example. In this device, when the battery terminal is removed, the capacitor 4
Since the voltage V _D charged in the RAM 1 is discharged by the resistor 5, erasing of the RAM 1 is performed in a short time approximately determined by the time constants of the capacitor 4 and the resistor 5. However, although the erasing time of the RAM 1 can be significantly shortened, the following new problem arises. In other words, since the current consumption of RAM1 is small, the contact resistance of the contact part in the power supply line of RAM1 tends to increase.
There is a high possibility that the power supply to RAM1 will be momentarily interrupted. Further, since the resistor 5 is provided in parallel with the capacitor 4, the backup time by the capacitor 4 is shortened. Therefore, when the power supply to the RAM 1 is momentarily cut off, there is a high possibility that the memory contents will be erased during this period, lowering the reliability and increasing the cost due to the provision of the resistor 5. Erasing this kind of memory is necessary when replacing a sensor that detects the engine operating status, such as an air flow meter, and it is necessary to improve it because it takes a long time to erase it, which leads to a decrease in maintenance efficiency. is desired. (Purpose of the invention) Therefore, the present invention has been devised so that after an abnormality occurs in the sensor output when the engine is in a predetermined operating state, when the engine returns to normal, the stored contents of the storage means (memory) are initialized, and the power supply is interrupted. The purpose is to sufficiently back up learning control values at the time of use, simplify the work required for initial settings such as when replacing sensors, prevent cost increases, and improve maintenance efficiency while maintaining reliability. (Means for Solving the Problems) In order to achieve the above object, the engine control information storage device according to the present invention has a sensor that detects physical quantities related to engine control, as shown in FIG. a, a control amount calculation means b that calculates a control amount for controlling the combustion state of the engine based on the output of the sensor a, and performs learning control on the control amount; Storage means c that holds this data and initializes the data when a command signal is input.
and a sensor signal determining means d for determining whether the output signal of the sensor a is normal or abnormal, and a subsequent output signal of the sensor signal determining means d when the output signal of the sensor a is determined to be abnormal. a return determination means e that determines that the sensor a has returned to normal based on the return determination means e; and based on the determination result of the return determination means e, when the sensor a returns to normal, the data of the learning control is rewritten and initialized. and an initial setting means f. (Operation) In the present invention, when an abnormality occurs in the sensor, the abnormality is determined by the sensor signal discrimination means, and based on the output signal of the sensor signal discrimination means,
The return determining means determines whether the sensor has returned to normal. Then, based on the determination result of the return determination means, when the sensor returns to normal, the initial setting means rewrites the learning control data in the storage means and initializes the learning control data, and the rewritten learning control data is retained even when the engine is stopped. be done. In this way, when a sensor abnormality occurs, it is automatically determined whether the abnormality has occurred and whether the sensor signal has returned to normal by replacing the sensor, and the learning control data is rewritten to initialize when the sensor signal returns to normal immediately after the sensor is replaced. It can be done. Therefore, without compromising the sufficient backup function in the event of a momentary power outage, the work required for initial settings when replacing the sensor is simplified, cost increases are prevented, and maintenance efficiency is improved while maintaining reliability. . (Example) Hereinafter, the present invention will be explained based on the drawings. FIGS. 2 and 3 are diagrams showing an embodiment in which the engine control information storage device according to the present invention is applied to an air-fuel ratio learning control device. First, the configuration will be explained. In Figure 2, 11
is the engine, and the intake air is from the air cleaner 12.
The fuel is supplied to each cylinder through an intake pipe 13, and is injected by an injector 14 based on an injection signal Si. The air-fuel mixture ignites and explodes at a predetermined ignition timing, and is discharged from the exhaust pipe 15 as exhaust. The intake air flow rate Qa is detected by, for example, a hot wire type air flow meter (sensor) 16, and is controlled by a throttle valve 17 in the intake pipe 13. The opening Cv of the throttle valve 17 is determined by the throttle sensor 18.
The temperature Tw of the cooling water flowing through the water jacket of the engine 11 is detected by the water temperature sensor 19.
Detected by Further, the rotational speed N of the engine 11 is detected by a crank angle sensor 20, and the oxygen concentration in exhaust gas is detected by an oxygen sensor 21. The oxygen sensor 21 outputs Vs at the stoichiometric air-fuel ratio.
Those with the characteristic of sudden changes are used. The outputs of the sensors 16, 18, 19, 20, and 21 are input to a control unit 31, and the control unit 31 has a function as a control amount calculation means. Control unit 3
1 is composed of a CPU 32, ROM 33, RAM 34, and I/O interface 35. The I/O interface 35 controls the input/output of signals in the control unit 31, and connects each of the sensors 16, 18, 19, 20, 21.
The output of is via the I/O interface 35.
It is input to the CPU 32. The CPU 32 uses the ROM 33 based on information from the I/O interface 35.
It calculates a processing value that will achieve the target air-fuel ratio according to the program stored in the engine, outputs the calculation result to the I/O interface 35, and calculates the processing value necessary for learning control according to the operating state of the engine 11. The data is stored in the RAM (storage means) 34 in map format. This RAM 34 is the same as the conventional example shown in FIG. 4, and its stored contents are backed up by constantly applying a predetermined voltage. That is, the RAM 34 can store data necessary for learning control and retain this data even after the engine is stopped.
When a predetermined command signal is input from the controller, the stored learning control data can be rewritten to a predetermined value and initialized. Also,
The operating state of the engine 11 is the RAM 34 for the CPU 32.
When it is determined that the operating state is the same as the one stored in the RAM 34, the processed value stored in the RAM 34 is read out.
Output to I/O interface 35. I/O
The interface 35 outputs the injection signal Si based on the processed value from the CPU 32. In this manner, the CPU 32 calculates processing values necessary for feedback control of the air-fuel ratio and outputs the injection signal Si, and also stores and updates learning values based on the feedback control. Further, the CPU 32 has a function as a sensor signal discriminating means for discriminating whether the output signal of the air flow meter 16 is normal or abnormal, and when it is determined that the output signal of the air flow meter 16 is abnormal, the CPU 32 performs subsequent sensor signal discrimination. It has a function as a return determination means for determining whether or not the air flow meter 16 has returned to normal based on the result (output signal of the sensor signal determination means). Furthermore, this CPU 32 has a function as an initial setting means that rewrites and initializes the learning control data in the RAM 34 when the air flow meter 16 returns to normal based on the determination result as a return determination means. If the output of air flow meter 16 becomes abnormal, for example,
When the harness is removed and the harness becomes open, when this is detected, a command to initialize the processing value stored in the RAM 34 is output to the RAM 34. The RAM 34 initializes the memory contents (not erases data) based on instructions from the CPU 32.
data rewriting). Next, the effect will be explained. Since the air-fuel ratio learning control according to this embodiment is well known, its explanation will be omitted. Here, the present embodiment is characterized by the method of initializing the storage contents of the RAM 34, which will be described in detail below. FIG. 3 is a flowchart showing a program for controlling the initial setting of the RAM. This program is started when the engine is started, and is repeatedly executed at predetermined intervals. First, at P ₁ , compare the engine speed N with the reference speed (for example, set to 600 rpm), and when N≧600 rpm, if the air flow meter 16 as a sensor is normal, the normal output will be output. Since this is the desired operating state, it is determined that the initial setting control can be determined, and the process proceeds to _P2 .
If N≦600 rpm, the determination cannot be made and the process returns. In P ₂ , the current intake air amount Qa, which is the output of the air flow meter 16, is set as the abnormality determination reference value Q _L
When Qa<Q _L , it is determined that there is an abnormality.
For example, when the air flow meter 16 is removed, the harness of the air flow meter 16 becomes open, so the amount of intake air input to the control unit 31 is

[0], and Qa<Q _L. Next, in P ₃ , it is determined whether the abnormal state that satisfies the condition Qa < Q _L has elapsed for a predetermined period of time, and if it has elapsed, the abnormality identification flag FNG is set in P ₄ , and it is determined that the abnormal state has not elapsed. Time to return. Therefore, when the air flow meter 16 is removed, it is determined that there has been no sensor signal for a predetermined period of time even though the engine 11 is rotating, and the flag FNG is set. Flag FNG is not set. If the air flow meter 16 is subsequently replaced and reattached, it will be necessary to initialize the learning control data in the RAM 34. In this embodiment, this is automatically executed by software. That is, after going through the above routine, if it is determined in _P2 that Qa≧ _QL , it is determined that the air flow meter 16 has been reinstalled and the output has returned to normal, and in _P5 it is determined that the abnormality identification flag FNG was previously set. Determine whether or not. When FNG=1, an abnormal state of the intake air amount Qa has been confirmed, so it is determined that it is necessary to initialize the learning control data stored in the RAM 34, and in P ₆ , the learning control data in the RAM 34 is initialized, Reset the abnormality identification flag at _P7 and return. Since this initial setting is not erasing the memory contents (the conventional method) but rewriting the memory contents with other initial data, it is instantaneously performed. In this way, when the air flow meter 16 is reattached after being removed, the stored contents of the RAM 34 are automatically initialized. Once this automatic initialization is done, the next routine
At _P5 , the flow branches to the NO instruction. As a result, when replacing the air flow meter 16, etc., the RAM 34
When initial settings are required, the previous data can be easily rewritten, improving maintenance efficiency. Also, at this time, RAM34
Since the backup is performed satisfactorily in the same configuration as the first conventional example, even if there is a momentary power outage, the reliability of the memory contents can be maintained without damaging the sufficient backup. With,
Cost increases can be prevented. moreover,
Since the process associated with the initial setting is a data rewriting process, it is extremely quick and efficient, unlike conventional data erasing. In this embodiment, an air flow meter is used as a sensor for detecting physical quantities related to engine control, but the present invention is not limited to this, and may be applied to, for example, a water temperature sensor, a crank angle sensor, or an oxygen sensor. Good too. (Effects) According to the present invention, when an abnormality occurs in a sensor, it is automatically determined whether the abnormality has occurred or whether the sensor signal returns to normal by replacing the sensor, and the learning control data is initialized when the sensor signal returns to normal immediately after the sensor is replaced. Since the rewriting is carried out in a similar manner, the time required for the initial setting work when replacing the sensor can be significantly shortened while ensuring sufficient backup performance against instantaneous power interruptions, etc. As a result, maintenance efficiency can be improved and costs can be reduced.
As a result, maintenance efficiency can be improved.

[Brief explanation of the drawing]

Fig. 1 is a basic conceptual diagram of the present invention, Figs. 2 and 3 are diagrams showing an embodiment of an engine control information storage device according to the present invention, Fig. 2 is an overall configuration diagram thereof, and Fig. 3 is a diagram showing an embodiment of the engine control information storage device according to the present invention. Flowcharts showing the initial setting control program, Figures 4 and 5 are diagrams showing a conventional engine control information storage device, Figure 4 is a circuit diagram showing a case where emphasis is placed on backup characteristics, and Figure 5
The figure is a circuit diagram showing a case where emphasis is placed on the erasing characteristic. 16... Air flow meter (sensor), 31...
...Control unit (control amount calculation means), 3
2...CPU (sensor signal discrimination means, return judgment means, initial setting means), 34...RAM (storage means).

Claims (1)

[Scope of Claim for Utility Model Registration] a) A sensor that detects a physical quantity related to engine control, and b) A control that calculates a control quantity to control the combustion state of the engine based on the output of the sensor and performs learning control of the control quantity. c) storage means for storing data necessary for the learning control, retaining this data even after the engine is stopped, and initializing the data when a command signal is input; d) the above-mentioned a sensor signal discriminator for discriminating whether the output signal of the sensor is normal or abnormal; and e) when the output signal of the sensor is determined to be abnormal, the sensor f) initial setting means for rewriting and initializing the learning control data when the sensor returns to normal based on the determination result of the return determining means;
An engine control information storage device comprising: