JPH0328578B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a memory backup monitoring device in a learning control device for an internal combustion engine for an automobile.

<Background Art> A learning control device in a feedback control system uses a basic control amount predetermined in correspondence with a target value, a feedback correction amount determined based on proportional-integral control by comparing the target value and the actual value, and a RAM. control amount setting means for setting a control amount from the learning correction amount stored in the RAM; and a control amount setting means for setting a control amount from the learning correction amount stored in the RAM.
learning correction amount updating means for updating learning correction amount data within the learning correction amount.

Specifically, for automobile internal combustion engines, an air-fuel ratio learning control device using a fuel injection valve 1 as shown in FIG. 1 and an idle speed learning control device using an idle control valve 2 have been considered.

The fuel injection valve 1 shown in Fig. 1 is of the so-called SPI type and is installed upstream of the throttle valve 3, and the valve opening time ratio (that is, the fuel injection amount) is determined according to the duty ratio of the pulse signal given to it. be done. Reference numeral 4 denotes a hot wire air flow meter for measuring the intake air flow rate, which is used to control the fuel injection amount. The idle control valve 2 shown in FIG. 1 is of a rotary type, and is installed in an auxiliary air passage 5 that bypasses the throttle valve 3, and the opening degree (that is, the amount of auxiliary air) is adjusted according to the duty ratio of the pulse signal given to the idle control valve 2. is determined.

As shown in Fig. 2, the air-fuel ratio learning control device calculates the basic injection amount Tp (=K×Q/N, K is a constant) from the intake air flow rate Q and the engine speed N. and a target air-fuel ratio (theoretical air-fuel ratio) and an actual air-fuel ratio detected based on a signal from an O ₂ sensor installed in the exhaust system, and set a feedback correction coefficient α using proportional-integral control. A correction coefficient setting means and a learning correction coefficient that searches for a learning correction coefficient α ₀ (initial value 1) stored in the RAM corresponding to engine operating conditions such as engine speed N and basic injection amount (load) Tp. A search means takes a weighted average (for example, a weighted average, see the following equation (1), M is a constant) of the feedback correction coefficient α and the learning correction coefficient α ₀ , and stores that value as a new learning correction coefficient α ₀ in the RAM. learning correction coefficient updating means for updating the data of the learning correction coefficient α ₀ under the same engine operating conditions; and _the injection quantity Ti (the following formula (2)); and a pulse signal output means that outputs a pulse signal with a duty ratio corresponding to the calculated injection amount Ti to the fuel injection valve.

α ₀ ←(α+(M−1)×α ₀ )/M…… (1) Ti=Tp×α×α ₀ …… (2) The idle speed learning control device is as shown in Figure 3. , basic control value setting means for setting the basic control value ISWtw of the duty ratio of the pulse signal based on the water temperature Tw;
A target rotation speed setting means for setting the target rotation speed Ns, a feedback correction amount setting means for comparing the target rotation speed Ns and the actual rotation speed N and setting a feedback correction amount ISCfb by comparison-integral control, and Correspondingly, a learning correction amount search means for searching the learning correction amount ISCle (initial value 0) stored in the RAM, and a weighted average (for example, a weighted average) of the feedback correction amount ISCfb and the learning correction amount ISCle,
(see the following equation (3)) and use that value as the new learning correction amount.
Learning correction update means for updating the data of ISCle by the learning correction amount of the same rotation speed N in RAM as ISCle, and feedback correction amount to the basic control value ISCtw.
The control value ISCdy of the duty ratio of the pulse signal is obtained by adding ISCfb and the learning correction amount ISCle (see the following formula (4))
and a pulse signal output means for outputting a pulse signal of a duty ratio based on the calculated control value to the idle control valve.

ISCle←(ISCfb+(M-1) ×ISCle)/M... (3) ISCdy=ISCtw+ISCfb +ISCle... (4) By the way, in such a learning control device for an automobile internal combustion engine, learning results are stored in RAM. In this case, when the engine key switch is turned off, power is supplied to the RAM without going through the engine key switch, so that the RAM is backed up and its contents are not erased.
If the contents of the RAM are damaged by removing the battery while the key is off, the next time the engine key switch is turned on, the learning will be based on the undefined contents of the RAM, causing an inconvenience.

In addition, according to Japanese Patent Application Laid-Open No. 57-102529, a constant with a predetermined pattern is stored in a specific address of RAM in advance, and when the program is started, it is checked whether the value of this constant is corrupted or not, that is, it is an incorrect value. It is disclosed that if the value is incorrect, it is assumed that the battery has been removed, and the RAM contents are initialized, but since the battery removal is not directly detected, the RAM contents When the destruction occurred in a part other than a specific address, there were problems in terms of safety, such as failure to be detected.

<Purpose of the Invention> In view of the above-mentioned actual situation, the present invention is designed to prevent power to the RAM from being cut off due to the battery being removed during key-off.
The purpose is to be able to detect and take action when the engine key switch is turned on again if the contents of RAM are corrupted.

<Structure of the Invention> Therefore, as shown in FIG. 4, the present invention includes a flip-flop that is inverted (for example, reset) by re-input after the input to the power supply terminal of the RAM for learning control disappears; Judgment means for judging the output of the flip-flop when the engine key switch is turned on; and based on the judgment result, when the flip-flop is inverted by the re-input, the learning correction amount data in the RAM is returned to the initial value, and the flip-flop is This configuration includes initialization means for re-inverting (for example, resetting).

<Example> Examples will be described below.

In FIG. 5, 11 is a CPU, 12 is a ROM, and these are further connected to a stabilizing regulator 15 via a battery 13 and an engine key switch 14.
Power is supplied via.

Reference numeral 16 denotes a RAM for learning control, to which power is supplied from the stabilizing regulator 15 via the diode 17 when the engine key switch 14 is on. Further, when the engine key switch 14 is off, power is supplied from a backup power supply circuit consisting of a resistor 18 and a Zener diode 19.

20 is a flip-flop whose reset (R) terminal is connected to the power supply terminal of the RAM 16. And the output (Q) of flip-flop 20
The terminal is connected to port A of CPU11. Furthermore, port B of the CPU 11 is connected to the set (S) terminal of the flip-flop 20.

Here, the CPU 11 operates the engine key switch 14 according to a program (stored in the ROM 12) based on the flowchart shown in FIG. 6 (memory backup monitoring routine started when the engine key switch 14 is turned on). When it is turned on, it is determined whether or not memory backup has been performed correctly up to that point, and if it has not been performed, appropriate processing is performed.

Next, the flowchart shown in FIG. 6 will be explained.

In S1, it is determined whether the input to port A of the CPU 11 (ie, the output of the flip-flop 20) is 1 or 0. If it is 1, it is determined to be normal and this routine is ended. If it is 0, it is determined that there is an abnormality and the process proceeds to the next step S2.

In S2, all learning results in the RAM 16 are returned to their initial values. In the case of an air-fuel ratio learning control device, all data of the learning correction coefficient α ₀ is set to 1. In the case of an idle rotation speed learning control device, set all learning correction ISCl data to 0. Next, proceed to S3.

At S3, an output of 1 is issued from port B of the CPU 11, the flip-flop 20 is set again, and the output is returned to 1.

Therefore, if the power to the RAM 16 is cut off by removing the battery 13 while the engine key switch 14 is off (see Figure 7), the input to the R terminal of the flip-flop 20 will disappear and the power will be turned off again. When the battery 13 is connected, the input to the R terminal of the flip-flop 20 becomes 1. At this time, the flip-flop 20 is reset and its output becomes 0.

Thereafter, when the engine key switch 14 is turned on and the routine shown in the flowchart of FIG. detected. In this case, return all learning results in RAM 16 to their initial values and start learning from the beginning.
Set the output of port B to 1 and flip-flop 2
0 to the S terminal sets flip-flop 20 and returns its output to 1.

Furthermore, if the battery 13 is not removed while the engine key switch 14 is turned off, the input to port A (that is, the output of the flip-flop 20) will become 1 when the engine key switch 14 is turned on. Therefore, in this case, it is determined that the memory was backed up normally.
The learning results in the RAM 16 are used as they are.

<Effects of the Invention> As explained above, according to the present invention, if the power is cut off while backing up RAM for learning control, this is detected when the engine key switch is turned on and the learning result is set to the initial value. Since the learning is performed again from the beginning, it is possible to prevent erroneous control from being performed by performing learning control based on the undefined RAM contents. reliability is improved.

In particular, since it uses a flip-flop to directly detect battery removal, it is extremely safe in terms of safety.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a throttle chamber of an internal combustion engine showing an example of mounting a fuel injection valve and an idle control valve, Fig. 2 is a block diagram showing the configuration of an air-fuel ratio learning control device, and Fig. 3 is an idle rotation FIG. 4 is a block diagram showing the configuration of the numerical learning control device, FIG. 5 is a circuit diagram showing an embodiment of the present invention, FIG. 6 is a flowchart of the same, and FIG. Figure 7 is the same timing chart as above. 1...Fuel injection valve, 2...Idle control valve, 1
1...CPU, 12...ROM, 13...Battery, 14...Engine key switch, 15...Stabilizing regulator, 16...Learning control
RAM, 20...Flip-flop.

Claims (1)

[Claims] 1 The control amount is calculated from the basic control amount predetermined in correspondence with the target value, the feedback correction amount determined based on proportional-integral control by comparing the target value and actual value, and the learning correction amount stored in RAM. A control amount setting means for setting a new learning correction amount from the feedback correction amount and learning correction amount, and
learning correction amount updating means for updating learning correction amount data in the RAM, and backing up the memory by supplying power to the RAM without going through the engine key switch when the engine key switch is off. The learning control device for an internal combustion engine for an automobile has a flip-flop that is inverted by re-input after the input to the power supply terminal of the RAM disappears, and a determination means that determines the output of the flip-flop when the engine key switch is turned on. , further comprising initialization means for returning the learning correction amount data in the RAM to the initial value and re-inverting the flip-flop when the flip-flop is being inverted by the re-input based on the determination result. A memory backup monitoring device in a learning control device for an automobile internal combustion engine.