JPH0380980B2 - - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an electronic control device for an automobile, and more particularly to a processor of an electronic control unit having a data retention memory that can be operated periodically or at a predetermined timing even after the ignition switch is turned off. wake up
This invention relates to an electronic control device for a vehicle that intermittently performs operations such as detecting the state of the vehicle, writing the detection result to a data holding memory, and returning to the rest state.

BACKGROUND OF THE INVENTION In an electronically controlled fuel injection device or the like, when starting an engine, if the engine condition is known in advance, appropriate starting control is possible. For example, it is well known that when starting at a high temperature, it is difficult to start using normal fuel injection control because the fuel pump pressure is low. In this case, prompt startup is possible by predicting the cooling water temperature before startup and increasing the normal injection amount. Therefore, it may be possible to provide a period of time to detect the state of the vehicle, such as the coolant temperature, before starting, but it is not appropriate to perform the above detection only during the period from when the ignition switch is turned on until the starter switch is turned on. Not. This is because the time from when the ignition switch is turned on until the starter switch is turned on is uncertain, and if the starter switch is turned on immediately after the ignition switch is turned on, detection will not be possible in time.

OBJECTS OF THE INVENTION The present invention has been made in view of the above circumstances, and its purpose is to reliably detect various states of the automobile before starting the engine.

Embodiment of the Invention FIG. 1 is an explanatory diagram of the configuration of an electronic control device for an automobile of the present invention, in which 1 is an automobile battery, 2 is an ignition switch, and 3 is connected to the automobile battery 1 via the ignition switch 2. The main power source 4 is a sub power source that is always connected to the automobile battery 1, and both power sources output a constant voltage from the battery voltage. Further, 5 is an electronic control section, which includes a processor 7 having a data holding memory 6. The processor 7 operates on the voltage supplied from the main power supply 3, and the data retention memory 6 operates on the voltage supplied from the sub power supply 4. Even if the voltage from the main power supply 3 stops, the voltage is supplied from the sub power supply 4. The contents of the data holding memory 6 are held as long as the data holding memory 6 is held. Data retention memory 6 is sometimes called standby RAM. 8 is an intermittent start control section, and sub power supply 4
Operates on voltage supplied from Therefore, even when the ignition switch 2 is off, it remains operable. When the ignition switch 2 is turned off, this intermittent start control section 8 turns on an intermittent switch 9 connected in parallel with the ignition switch 2 periodically or at a fixed timing, and then starts operating the main power source 3. After that, the intermittent signal is sent to the processor 7, and when the intermittent operation end signal is received from the processor 7, the process of turning off the intermittent switch 9 is repeated. When the processor 7 receives the intermittent signal, it detects the state of the vehicle and writes the detection results into the data holding memory 6.

FIG. 2 is a flowchart showing an example of the processing of the processor 7. When the ignition switch 2 or the intermittent switch 9 is turned on and voltage is supplied from the main power supply 3, normal initialization (however, (including turning off the intermittent operation end signal) (S1), it is determined whether or not an intermittent signal has been issued, that is, whether or not the intermittent activation has been performed (S2), and if the intermittent activation has been performed, the vehicle Intermittent control is executed, such as detecting various states of and writing the detection results to the data holding memory 6 (S3), and when the intermittent control is completed, the intermittent control end signal is turned on (S4). Further, when the ignition switch 2 is not intermittently started, that is, in a normal state in which the ignition switch 2 is turned on, the normal control of step S5 is executed. In this normal control, the contents of the data holding memory 6 are taken into account and the original control, for example, engine control, is executed.

FIG. 3 is a block diagram of a main part of one embodiment of the intermittent activation control section 8, and FIG. 4 is a timing chart showing the signals a to g of each section in FIG. 3 and the output state of the main power supply 3. When the ignition switch 2 is on, the output a of the driver 30 is "1", and the outputs of the time limit circuits 31, 32 and flags 33, 34 are all "0", meaning they are in a clear state. Therefore, the output of the driver 35 is "0" and the transistor 36 forming the intermittent switch 9 is off. When ignition switch 2 turns off, timer circuit 3
1 and 32 start counting. Here, timed circuit 3
1 sets the output b to "1" after a relatively short period of time, for example several minutes to several tens of minutes, and the time limit circuit 32
After a relatively long period of time, for example from several hours to several tens of hours, the output f becomes "1". Therefore,
When the set time of the time limit circuit 31 has elapsed after the ignition switch 2 is turned off, the flag 33 is set, its output c becomes "1", and the driver 35
The transistor 36 is turned on via the
An intermittent activation signal is sent to the electronic control unit 5. When the electronic control unit 5 issues an intermittent operation end signal indicating that the predetermined intermittent control has ended, this signal d restarts the timer circuit 31 and the flag 33 via the OR circuit 37. Therefore, after the set time of the time limit circuit 31 has elapsed, the transistor 36 is turned on again and the intermittent activation signal is sent out. In addition, time limit circuit 3
When the set time 2 has elapsed, the flag 34 is set by the output f, and the output g becomes "1" and continues to clear the timer circuit 31 and the flag 33. Therefore, the above-mentioned periodic intermittent starting operation is performed by the timer circuit. It is stopped after the set time of 32 has elapsed.

FIG. 5 is a block diagram of main parts of another embodiment of the intermittent activation control section 8, and FIG. 6 is a timing chart showing an example of signal waveforms of each part shown in FIG. 5. The same reference numerals as in FIG. 3 indicate the same parts. . While the embodiment shown in FIG. 3 enables intermittent operation at a fixed period,
In this embodiment, the period of intermittent operation is gradually increased.

In FIG. 5, while the ignition switch 2 is on, the signal a is "1" and the OR circuit 5
The flag 52 is held in a clear state by the output of 0 (“1”). Therefore, the output of the flag 52 is "0" and the transistor 36 is off. Also,
The flag 53 maintains a clear state. When the ignition switch 2 is turned off, its falling edge becomes an initialization signal for the 8-bit shift register 54, and the value of ¥01 is initially set in the shift register 54. Further, the fall of the output j of the OR circuit 50 becomes a load signal for the 16-bit presettable down counter 51, and the down counter 5
The value of ¥01 is loaded into the upper 8 bits of 1. This down counter 51 is counted down by a 1 Hz clock 55, and a flag 52 is set by the borrow signal h. Therefore, at first, after turning off the ignition switch 2,
After 4.3 minutes, transistor 36 is turned on and an intermittent activation signal is sent. Also, flag 5
The output i of 2 becomes the shift clock of the shift register 54, and the contents of the shift register 54 are set to ¥02.

Since the intermittent operation end signal d is input to the OR circuit 50, the down counter 51 is loaded again when the intermittent control operation is completed. The load value at this time is ¥02. Therefore, next time, the intermittent activation signal will be issued after about 8.6 minutes. Thereafter, intermittent control is executed every 17, 34, and 68 minutes, and when the shift register 54 is shifted eight times and the flag 53 is set by the output of the shift register 54, the output of the OR circuit 50 becomes "1". is maintained and intermittent control is stopped.

Generally, the coolant temperature during high-speed driving is about 80°C, but after the vehicle is stopped and the engine is turned off, the coolant temperature increases rapidly, as shown in FIG. 7, for example, and then settles to the outside temperature after a few hours. Therefore, immediately after the engine is stopped, it is necessary to detect the cooling water temperature at relatively short intervals, but after a certain period of time there is little change in temperature, so there is no problem in increasing the interval. The embodiment shown in FIG. 5 is suitable for such a case.

FIG. 8 is a block diagram of a main part of still another embodiment of the present invention, and the same reference numerals as in FIGS. 1 and 5 indicate the same parts. In this embodiment, the intermittent activation control section 8 is constructed by a microprocessor 80, and FIG. 9 shows an example of processing by the microprocessor 80. As shown in the figure, when the microprocessor 80 is supplied with the operating voltage from the sub power supply 4, it performs normal initialization processing (S10) and determines whether the ignition switch 2 is on or off (S11). When the ignition switch 2 is on, the microprocessor 80 initializes the intermittent control, that is, turns off the intermittent activation signal, sets the contents of registers M and n to zero, and sets the contents of register N to A (S12). . Further, additional control processing such as disconnection detection of various lamps installed in the automobile is performed (S13).

When ignition switch 2 is turned off, the contents of register M are counted up by 1 and compared with the contents of register N (S14, S15). If they match, the contents of register M are set to zero (S16), and the contents of register N are incremented by 1.
The contents of register N are counted up by 1 (S17), the contents of register N are set to the value obtained by multiplying the previous contents by ²ⁿ (S18), and the intermittent activation signal is turned on (S19). By turning on this intermittent activation signal, the transistor 84,
36 is turned on, the main power supply 3 is activated, and the operating voltage is supplied to the processor 7. Further, when the intermittent activation signal is turned on, an instruction for intermittent control is notified to the processor 7.

Next, the microprocessor 80 implements a soft delay (S20). This delay occurs after the transistor 36 is turned on by the intermittent activation signal and when the processor 7
At least the time required for the intermittent operation end signal to be turned off in the initialization of step S1 in FIG. 2 is given, and usually within 1 ms. And after this, the microprocessor 80
determines whether or not the intermittent operation end signal is turned on (S21), and if it is turned on, the intermittent start signal is turned off to stop the operation of the main power supply 3 and processor 7 (S22).

If the ignition switch 2 continues to be off, the processes from step S14 onwards are repeated.
Next time, the value of N will be larger than the previous time, so the period of intermittent activation will be longer. That is, in this embodiment, the period is gradually increased, similar to the embodiment shown in FIG.

The A/D converter 81, input interface circuit 82, and output buffer circuit 83 connected to the processor 7 are peripheral circuits of the processor 7 and constitute an electronic control section.
1, analog signals from a cooling water temperature sensor, an intake temperature sensor, an atmospheric pressure sensor, etc. (not shown) are converted into digital signals, input to the processor 7, and stored in the data holding memory 6. Further, the output buffer circuit 83 is connected to, for example, an actuator.

Although the present invention has been described above with reference to Examples, the present invention is not limited to the above-mentioned Examples, and various additions and changes can be made. For example, it is free to gradually shorten the intermittent period.

Effects of the Invention As explained above, according to the present invention, the electronic control is performed at a fixed period or at a predetermined timing during the engine stop period after the ignition switch is turned off until the next ignition switch is turned on. The processor that makes up the engine is awakened, detects the state of the vehicle necessary for the original control, and writes the detection results to the data holding memory, ensuring that various states of the vehicle are detected before the engine starts. becomes possible. Therefore, even if the starter switch is turned on immediately after the ignition switch is turned on, optimal starting control is possible based on the data stored in the data retention memory in advance, ensuring smooth engine starting. Not only is this possible, but it is also highly effective in terms of exhaust purification and fuel efficiency. Furthermore, in the present invention, the electronic control section is not always awakened during the off period of the ignition switch 2, but is awakened only for a very short period of time, and is stopped most of the time. Since the intermittent activation control section that operates while the switch 2 is off consumes less power than the electronic control section, it has the advantage that the dark current does not need to increase much. For example, if the intermittent startup control section
- If a microprocessor with 4 bits of MOS and 1K ROM is used, the current consumption will only increase by about 1 mA, which is much smaller than the allowable dark current of an automobile, which is 10 mA.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of the automotive electronic control device of the present invention, FIG. 2 is a flowchart showing an example of processing by the processor 7, and FIG. 3 is a main part block diagram of an embodiment of the intermittent start control section 8. , FIG. 4 is a timing chart showing the signals a to g of each part in FIG. 3 and the output state of the main power supply 3, and FIG.
FIG. 6 is a timing chart showing an example of signal waveforms of each part shown in FIG.
Figure 7 is a diagram showing an example of changes in cooling water temperature;
The figure is a main part block diagram of yet another embodiment of the present invention.
FIG. 9 is a flowchart showing an example of processing by the microprocessor 80. 1 is a car battery, 2 is an ignition switch, 3 is a main power supply, 4 is a sub power supply, 5 is an electronic control unit, 6 is a data holding memory, 7 is a processor, 8 is an intermittent start control unit, and 9 is an intermittent switch. be.

Claims (1)

[Claims] 1 a main power source connected to an automobile battery via an ignition switch, a sub power source connected to the automobile battery, and an intermittent switch connected in parallel to the ignition switch;
After the ignition switch is supplied with operating voltage from the sub-power source, the intermittent switch is turned on at predetermined time intervals during the engine stop period until the next ignition switch is turned on, and the main power source is discharged from the battery. an intermittent start control means that repeats a process of sending out an intermittent start signal after connection and, upon receiving an intermittent operation end signal, turning off the indirect switch and disconnecting the main power source from the battery; an electronic control unit that, upon receiving the intermittent start signal, detects the state of the vehicle, writes the detection result to a data holding memory operated by the sub power source, and generates the intermittent operation end signal after the process is completed; An electronic control device for an automobile characterized by the following: