JPH02271719A - Analog/digital converter - Google Patents

Abstract

PURPOSE:To attain optimum control by providing a switch selecting plural analog signals, an A/D converter, a memory, a circuit leading a signal for each time interval and a circuit introducing a signal at each time interval different from the former time interval. CONSTITUTION:A 1st command signal M1 is supplied from a processing circuit 7 to a changeover switch 2 and an A/D converter circuit 6 for each predetermined time interval W3. A signal of the time period system is fed to channels 3b-3f, the signal is converted by the A/D converter 6 and supplied to the circuit 7. While a signal M1 is stored in a memory 15, when a 2nd command signal is introduced, the content of the memory 15 is rewritten from the signal M1 into the signal M2. When the signal M1 is introduced while the signal M2 is stored, the content of the memory is not rewritten. Thus, the A/D conversion of the output from a peak hold circuit 14 being a signal of a crank angle period system based on the signal M2 is surely executed without being neglected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an analog/digital conversion device, and more particularly, the present invention relates to an analog/digital conversion device for analog/digital conversion of signals derived in parallel at different timings in one analog/digital conversion circuit. The analog/digital converter is an analog/digital converter that performs the conversion and can suitably perform the conversion when there is a signal that should be prioritized.

Conventional technology For example, in fuel injection control devices for internal combustion engines in automobiles, analog signals from multiple sensors are sequentially converted using a single analog/digital conversion (hereinafter referred to as rA/D conversion) circuit. The data is converted into a digital value and sent to a processing circuit to control the opening and closing of fuel injection valves.

The analog signals given to the A/D conversion circuit include signals that are sequentially selected and given at predetermined time intervals of, for example, 1 m5ec, and signals that are given sequentially in synchronization with the crank angle. . The former are time-periodic signals, such as the output PM of an intake air pressure sensor, the output THW of a water temperature sensor, and the output TA of a throttle valve opening sensor. On the other hand, the latter is a crank angle periodic signal, such as an output N obtained by passing a signal from a knocking sensor through a peak hold circuit.

Conventionally, the following procedure is used to sequentially convert analog signals derived at specific timings into digital values by one A/D conversion circuit.

The time periodic signal, ie, the output from each sensor, is individually given to each channel of a changeover switch connected to an A/D conversion circuit. Processing circuit every 1m5ec,
Applying a first command signal M1 to the changeover switch to instruct the channel to be switched in order to convert the time periodic signal;
For example, the 9112th sensor reads the output from the sensor given to the sequentially switched channels into the A/D conversion circuit.
1<1>, time t for each period W1 of 1m5ec
o.

Switch the channel of the changeover switch at tl and t2,
Output PM and THW from each senna, respectively.

The figure shows the timing at which TA is sequentially read into the A/D conversion circuit via the changeover switch and applied to the processing circuit after conversion. Each @l'lW 1 is an execution period Wll in which the analog signal read in is converted into a digital value in an A/D conversion circuit, and is given to a processing circuit to perform arithmetic processing, etc., in other words, performs A/D conversion operation. and a timing period W12 from the end of the execution period until the A/D conversion circuit starts reading time periodic signals. Note that the execution period is not necessarily the same time interval for each read output.

Further, the crank angle periodic signal, that is, the output from the peak hold circuit that has passed through the knocking sensor, is given to the remaining channels of the changeover switch. In addition to the first command signal M1, the processing circuit also instructs the channel to be switched in order to convert the crank angle periodic signal every predetermined period %flW2 based on the output from the crank angle sensor. A second command signal M2 is applied to the changeover switch, and the output from the peak hold circuit applied to the channel to be changed is read into the A/D conversion circuit.

For example, in a 4-cycle, 4-cylinder spark-ignition internal combustion engine, the top dead center TDC of each cylinder is located every 180° CA in terms of crank angle. The knocking senna is installed near the cylinder.
detecting the amount of vibration after top dead center TDC in the cylinder;
Detect the maximum amplitude with the peak hold circuit. Therefore, the timing at which the output from the peak hold circuit is A/D converted is every approximately 90° CA of the crank angle after the top dead center TDC of each cylinder. In FIG. 9(2), the A/D conversion operation of the output N1 from the knocking sensor for the first cylinder via the peak hold circuit is performed with the time distribution matching the timing chart of FIG. 9(1). It shows the right timing. Note that in FIG. 9(2), period W2 is a period from the top dead center of the third cylinder TDC(3) to a crank angle of 90'' CA.

In FIG. 9 (1), during the waiting period rWIW12,
A/D conversion is not performed on the time periodic signal. Therefore, at time t3 during the waiting period W12, as shown in FIG. 9(2), the crank angle periodic signal, the second When the command signal M2 is applied to the changeover switch, the channel of the changeover switch is switched from the channel to which the time periodic signal is applied, and the signal from the peak hold circuit is read into the A/D conversion circuit and A/D conversion is performed. An action is taken.

When the A/D conversion operation of the crank angle periodic signal is started during the waiting period, the A/D conversion operation of the crank angle periodic signal is started even though it is the time when the time periodic signal should be converted.
While the conversion operation is continuing, A of the time periodic signal is
/D conversion operation may not be started. For example, Figure 9 (1).

As shown in (2), at time t1, the A/D conversion operation of the output N1 from the peak hold circuit, which is a crank angle periodic signal at time t3 before the time t1, continues; Even though the output T)IW from the water temperature sensor, which is the signal of , is the timing to start the A/D conversion operation, the A/D conversion operation cannot be started.

Figure 9 (3) shows the A/
A timing chart of signals processed by the A/D conversion circuit when a D conversion operation is requested is shown. Assuming the above case, a memory is provided in advance in the processing circuit. In other words, even if it is the timing to convert the time periodic signal, if the A/D conversion operation of the crank angle periodic signal is ongoing, the time periodic signal that should have been converted will not be given. A first command signal M1 indicating the channel being assigned is stored in said memory. Thereafter, after the A/D conversion operation of the crank angle periodic signal is completed, the first command signal M1 is read out from the memory, the channel of the changeover switch is switched based on the command signal, and the time periodic signal is The A/D conversion operation of the output THW is started.

That is, in FIG. 9(3), the A/D conversion operation of the output THW of the water temperature sensor starts from time t4. after that,
As shown in FIG. 9(3), the cycle of the time-periodic signal, that is, the timing of period W1 is restored, and at time t2, the channel of the changeover switch is changed in order to read the following time-periodic signal, Thereafter, an A/D conversion operation is performed.

Utilization of the memory is for A/D of crank angle periodic signals.
This is done in response to an interruption of A/D conversion of a time-periodic signal during a conversion operation, but conversely, the A/D conversion of a crank angle periodic signal is performed during an A/D conversion of a time-periodic signal. The memory is similarly utilized when an interrupt for a D conversion operation is requested. Furthermore, when the conversion operation starts based on the command signal stored in the memory,
The stored contents in memory are erased.

The tenth factor is a flowchart for explaining the control operation performed during the standby period rfRW1:2. First, in step s1, a processing operation such as arithmetic processing is performed in the processing circuit based on the A/D converted digital value, and in step s2, a command signal indicating a channel to be subsequently switched is stored in the memory. It is determined whether there is or not. If the command signal is not stored, processing proceeds to other processing and subsequent processing within the processing circuit is performed.

On the other hand, if the command signal is stored in the memory in step s2, it is determined that the previous A/D conversion operation is still continuing, and the process proceeds to step s3, where the previous A/D conversion operation is continued. Immediately after the A/D conversion operation is completed, the channel of the changeover switch is changed to start the continuation A/D conversion operation, the stored command signal is erased in step S4, and the process proceeds to other processing.

Problems to be Solved by the Invention According to the above configuration, the A of one of the periodic signals is
Even during the /D conversion operation, it is possible to start the next A/D conversion operation immediately after the end of the A/D conversion operation by utilizing memory, but the following problems occur. .

For example, at time 10, A/
Even though the D conversion operation has started, the processing circuit is interrupted by another processing operation, and the converted digital value cannot be given to the processing circuit from the A/D conversion circuit. There is a case where the period corresponding to the execution period Wit in ') is extended, and the A/D conversion operation is still continuing even at time t1, which is the switching request timing of the time periodic signal. In the above case, as described above, the memory is utilized at the time t1, and then A/
A command signal indicating the channel to be switched to in order to perform a D-conversion operation is stored in the memory. 11th (J(1)
Referring to , at time t1, a first command signal M1 indicating the channel to which the output THW of the water temperature sensor is applied is stored in the memory. At time t5 after the above-mentioned time tl, the ongoing intake air pressure output p M is A/
When the Dg: conversion operation is completed, the A/D conversion operation of the output THW of the water temperature sensor starts.

By the way, the 111th! ! As shown in l (2>,
Time t within the period W5 from the aforementioned time t1 to time t5
6, even if the second command signal M2 requesting switching of the channel of the changeover switch is derived to start the A/D conversion operation of the signal from the peak hold circuit, which is a crank angle periodic signal, the above-mentioned signal has already been derived. Since the first command signal M1 is stored in the memory, the second command signal M
2 cannot be stored, i.e. the 11th [!
i? As shown in I(3), the A/D conversion operation of the crank angle periodic signal requested during the period W5 cannot be performed and is ignored. Therefore, in the 1111P, the output TH from the ink sensor
After the A/D conversion operation of W is completed, the A/D conversion of the output TA of the throttle valve opening sensor starts from time t2 after a waiting period.
The D conversion operation starts, and the A/D conversion operation of the output N1 from the knocking sensor via the peak hold circuit is not performed.

Generally, as described above, the output from the knocking sensor represents the degree of vibration, etc. applied to the internal combustion engine. Therefore, with excessive knocking, the valve, spark plug,
Furthermore, it may even lead to damage to the piston, etc., and the output from the knocking sensor is an important signal that requires appropriate control of the opening/closing angle of the fuel injection valve in response to the output. On the other hand, the time periodic signal is
Even if it is ignored to some extent, it will not cause much trouble in control compared to the output from the knocking sensor. That is, it can be considered that the A/D conversion operation of the crank angle periodic signal must be performed preferentially over the A/D conversion operation of the time periodic signal. However, in the conventional configuration described above, if the A/D conversion operation of the time periodic signal is continued for more than a predetermined time as described above, the A/D conversion operation of the crank angle periodic signal requested at a certain timing is
/D conversion dynamic f? Is it true that things are ignored? ! ff problem arises.

It is an object of the present invention to provide an analog/digital conversion based on a second command signal to be converted from analog to digital, which is required every second time interval.
An object of the present invention is to provide an analog/digital conversion device that can reliably execute digital conversion operations without neglecting them.

Means for Solving the Problems The present invention provides: a changeover switch that selects a plurality of analog signals one by one; an analog/digital conversion circuit that converts the output of the changeover switch into a digital value; and a channel to be switched by the changeover switch. a first command circuit that derives a first command signal to be converted from analog to digital at each predetermined first time interval; and a predetermined second time different from the first time interval. a second command circuit that derives a second command signal to be converted from analog to digital at intervals; and a continuous operation of analog/digital conversion by the analog/digital conversion circuit and/or arithmetic processing based on the analog/digital conversion. a first control means for storing the first command signal in the memory when the first command signal is derived from the first command circuit; and with the first command signal being stored in the memory; ,
When a second command signal is derived from the second command circuit,
a second command signal for rewriting the stored contents of the memory into a second command signal;
An analog device characterized by comprising: a control means; and a third control means for switching the channel of the changeover switch based on a first command signal or a second command signal stored in the memory after the completion of the continuous operation. /Digital conversion device.

According to the analog/digital conversion device of the present invention, a plurality of analog signals are selected one by one and applied to the changeover switch, and the output of the changeover switch is converted into a digital value by the analog/digital conversion circuit. . The changeover switch and the analog/digital conversion circuit are provided with a first command signal indicating a channel to be switched by the changeover switch in order to perform analog/digital conversion at each predetermined first time interval from a first command circuit. Further, a second command signal indicating a channel to be switched by the changeover switch is given from a second command circuit in order to perform analog/digital conversion at every predetermined second time interval different from the first time interval. When a first command signal is derived from the first command circuit during the continuous operation of analog/digital conversion by the analog/digital conversion circuit and/or arithmetic processing based on the analog/digital conversion, the first control means The first command signal is stored in a pre-provided memory. After the continuous operation is completed, the channel of the changeover switch is changed by the third control means based on the first command signal stored in the memory, and analog/digital conversion is started. On the other hand, when a second command signal is derived from the second command circuit while the first command signal is stored in the memory, the contents stored in the memory are transferred to the second command signal by the second control means. Can be rewritten.

Therefore, after the continuous operation is completed, the channel of the changeover switch is switched by the third control means based on the second command signal stored in the memory, and analog/digital conversion is started.

Therefore, the analog/digital conversion fF of the signal given to the analog/digital conversion circuit from the channel switched based on the second command signal can be executed without being ignored. Therefore, the second
If the signal to be converted based on the command signal is the output from the knocking sensor, it is possible to reliably control the opening and closing of the fuel injection valve in response to the output, thereby preventing damage to the internal combustion engine. can be avoided.

Embodiment FIG. 1 is a block diagram showing a simplified configuration of an analog/digital converter that is an embodiment of the present invention. The configuration of the analog/digital converter 1 will be explained with reference to FIG.

The changeover switch 2 is provided with a plurality of channels 3, and outputs from various sensors and the like are individually given to each of the channels 3a to 3f.

Note that the individual channels 3tt to 3f are collectively referred to as reference numeral 3. When each channel 3 and the output end 4 are connected by the connecting piece 5, the analog signal applied to the connected channels is converted to a digital value via the A/D conversion circuit 6, and is applied to the processing circuit 7. Processed. The calculation results processed by the processing circuit 7 are outputted via the input/output circuit 16, and the opening/closing control of the fuel injection valve 17 and the control of the switch 18 of the ignition-next circuit are performed.

Each channel 3 is provided with an output to be converted at a timing of every predetermined first time interval, for example every 1 m5ec, and an output to be converted at every period of the crank angle. The former includes the output PM of the intake air pressure sensor 8 and the output THW of the water temperature sensor 9 as time periodic signals.
, the output THA of the intake air temperature increaser 10, the electromotive force B of the battery 11, and the output TA of the throttle valve opening increaser 12. given separately. The latter includes an output N from a knocking sensor 13 disposed near each cylinder via a peak hold circuit 14 as a crank angle periodic signal. In addition, in this example,
A 4-stroke, 4-cylinder, spark-ignition internal combustion engine is assumed, and the knocking sensor 13 placed near the cylinder and the peak hold circuit 14 to which the output from the knocking sensor is given perform processing for 4 cylinders in one set. The peak hold circuit 14 outputs outputs N1 to N for four cylinders.
4 are individually derived, and channel 3 of said changeover switch 2
given to a.

From the processing circuit 7, a first command signal is given to the changeover switch 2 and the A/D conversion circuit 6 via the line S11 at every predetermined time interval W3, and the channels 3b to 3b to which the time periodic signals are given are given. 3f, and the A/D conversion operation is sequentially performed in the A/D conversion circuit 6.
The signal is applied to the processing circuit 7.

The second time is a timing chart showing the timing of the A/D conversion operation of a time periodic signal, in which the channel of the changeover switch is changed based on the first command signal M1 every second time interval W3, and each sensor The output from A
/D conversion operation is performed. The first time interval W3 is an execution period W31 during which A/D conversion is performed, a signal indicating the completion of the conversion is given to the processing circuit 7, and arithmetic processing is performed, that is, an A/D conversion operation is performed; It consists of a waiting period W32 from the end of the period until the conversion operation starts, and each period W31°WB2 differs depending on the amount of information from each sensor 8-12. Changeover switch 2
The order in which the channels are switched is, for example, as shown in FIG.

Further, a second command signal is sent from the processing circuit 7 to the changeover switch 2 and the A/D via the signal line sZ1 at a second time interval different from the first time interval W3, that is, at a time interval synchronized with the crank angle. The signal of the crank angle periodic system is applied to the conversion circuit 6 and switched to the channel 3a to which the signal of the crank angle periodic system is applied, and the output from the knocking sensor 13 via the peak hold circuit 14 is sequentially applied to the A/D conversion circuit 6 for A/D conversion operation. and provided to the processing circuit 7.

FIG. 3 is a diagram showing the crank angle. In this embodiment, four cylinders are assumed, so the top dead center TDC of each cylinder is
is configured to be present every 180"CA in terms of crank angle. Knocking is likely to occur during a period in which the crank angle has progressed from the top dead center TDC. Therefore, the knocking sensor disposed near the cylinder 13
The timing at which the output should be read into the A/D conversion circuit through the peak hold circuit 14 is at the top dead center TD of each cylinder.
The timing is set so that the crank angle is approximately 90° CA from C. In FIG. 3, assuming that the top dead centers TDC of the first and fourth cylinders are the highest points, the top dead centers TDC of the second and third cylinders are the lowest points. Furthermore, the output N from the peak hold circuit corresponding to each cylinder
1 to N4, the A/D conversion operation is required at the time when 90"CA of crank angle has passed from the top dead center TDC of each cylinder.

Incidentally, detection of the rank angle necessary for deriving the second command signal M2 is performed by the crank angle sensor 19 in FIG. 1, and the detected signal is provided to the processing circuit 7 via the input/output circuit 16.

The fourth time is a timing chart showing the timing of A/D conversion operation of a crank angle periodic signal. As mentioned above, the timing of the A/D '2 conversion operation of the crank angle periodic signal is the time required for the crank angle to reach 180'' CAN and for the crankshaft to rotate through the 180° CA. is the second time interval W4.

The second time interval W4 is a calculation period W41 in which the output from the knocking sensor is calculated in a peak hold circuit;
It consists of an execution period W42 in which the output N from the peak hold circuit is given to the A/D conversion circuit 6 and an A/D conversion operation is performed, and a waiting time W43 after the execution is completed.

After the execution period W42 has elapsed, the processing circuit 7 supplies a reset signal to each peak hold circuit 14 via the line s12, and the peak hold circuit 14 is initialized.

Therefore, in the processing circuit 7, the first command signal M1 is derived every first time closing interval W3, and the first
A second command signal M2 is derived every time interval W4, and 1. Each command signal is given to the changeover switch 2 and the A/D conversion circuit 6. Based on each command signal derived, the changeover switch is switched to any of the channels 3a to 3f, and the A/
The analog signal led to the D conversion circuit 6 is converted into a digital value and provided to the processing circuit 7.

In addition, when the changeover switch 2 is switched at each timing of a plurality of (two types in this embodiment) processed in parallel by one A/D conversion circuit as described above, for example, when a time periodic signal or During the execution period of the A/D conversion operation of one of the periodic signals of the crank angle periodic system,
There are times when it is required to perform the other A/D conversion operation.

At this time, a command signal indicating the requested channel to be switched is temporarily stored in the memory 15 provided in the processing circuit 7 in advance. Thereafter, after the ongoing execution period ends, the channel of the changeover switch 2 is switched based on the command signal stored in the memory 15, and the A/D conversion operation of the signal given to the switched channel is performed. Start. Note that after the command signal stored in the memory 15 is read out, the contents stored in the memory 15 are erased.

Further, in this embodiment, while the first command signal M1 is stored in the memory 15, the second command signal M1 is stored in the memory 15.
2 is derived, the contents stored in the memory 15 are rewritten from the first command signal M1 to the second command signal M2. Furthermore, when the first command signal M1 is derived while the second command signal M2 is stored, the stored contents of the memory are not rewritten. The A/D conversion operation of the output from the peak hold circuit 14, which is an angular periodic signal, is not ignored and is reliably executed.

FIG. 5 is a timing chart for explaining the control operation in this embodiment. FIG. 5(1) shows a state in which a first command signal M1 requesting an A/D conversion operation of a time periodic signal is derived every first time interval W3, and FIG. 5(2) , a second command signal M requests an A/D conversion operation of a crank angle periodic signal at every second time interval W4.
The derived state of 2 is further shown in Figure 5 (3).
The state in which the A/D conversion operation is performed in the A/D conversion circuit 6 based on the request is shown assuming that the same time elapses.

For example, as shown in FIG. 5, at time t10, even though the A/D conversion operation of the output P M from the intake air pressure sensor 8 has started, due to an interruption of other processing to the processing circuit 7. , said execution period is extended, and then A/
Assume that the execution period is still continuing even at time tll when the first command signal M1 for performing the D conversion operation is derived. In the i% range, a first command signal 811 is stored in the memory 15 indicating that the changeover switch is to be switched to the channel to which the output THW of the water temperature sensor 9 to be subsequently converted is applied. Thereafter, when the ongoing execution period ends without the second command signal M2 being derived, the output THW of the water temperature sensor 9 is determined based on the first command signal M1 stored in the memory 15. The selector switch is switched to the channel where the A/D is given.
Conversion operation begins.

On the other hand, for example, at the time t12, which is the time t11gk and is during the continuation of the execution period, the channel 12 indicating the channel to which the output Nl (output to the first cylinder) from the knocking sensor 13 via the peak hold circuit 14 is given. Assume that the second command signal M2 is derived. In this embodiment, in the P4 session, the first command signal M1 indicating the switching signal to the channel to which the output THW of the water temperature sensor 9, which has already been stored in the memory 15, is given is erased, and the second command signal M1 is deleted. Change g to command signal M2. Therefore, after the A/D conversion operation of the output P M of the intake air pressure sensor 8 is completed, the A/D conversion of the output N1 from the peak hold circuit 14 is performed based on the second command signal M2 stored in the memory 15. Start D conversion conversion operation. That is, the first command signal M1 indicating the channel to which the output THW of the water temperature sensor 9 that has been previously set is ignored. In FIG. 5, after the A/D conversion operation based on the second command signal M2 is completed, the output TA of the throttle valve opening sensor 12 is changed based on the first command signal M1 from time t13.
A/D conversion operation starts.

According to the above-described configuration, A/ of each crank angle periodic signal is
0 The D conversion operation is not ignored and is executed reliably.
In this embodiment, it is possible to reliably detect an undesirable state such as excessive knocking, and to appropriately control the opening and closing of the fuel injection valve based on the detection signal.
As a result, damage to the internal combustion engine can be avoided. Further, in order to preferentially execute the A/D conversion operation of the crank angle periodic signal as an A/D transformation change operation of the time periodic signal, the A/D conversion operation of the time periodic signal is performed. Even if there are four events that are ignored, there is almost no problem in controlling the internal combustion engine.

FIG. 6 is a flowchart for explaining the A/D conversion operation of time periodic signals, FIG. 7 is a flowchart for explaining the A/D conversion operation of crank angle periodic signals,
Furthermore, the programs shown in FIGS. 6 and 7, in which FIG. 8 is a flowchart for explaining the judgment operation in the standby judgment process, are processed in parallel in the processing circuit 7.

The program shown in FIG.
It starts when 1 is derived. First, in step m1, the channel of the changeover switch is changed based on the first command signal M1, and in step m2, the standby determination processing program shown in FIG. 8 is started.

When the program for the standby determination process starts, as shown in FIG. 8, it is first determined in step n1 whether the A/D conversion operation is being executed or not. If it is not being executed, the process proceeds to step n2, starts an A/D conversion operation, and returns to the program shown in FIG. 6. on the other hand,
If it is determined in step n1 that the A/D changing operation is being executed, the process proceeds to step n3, where it is determined whether or not a command signal is stored in the memory 15. If no command signal is stored, the process proceeds to step r14, stores the derived first command signal in the memory, and then returns to the program shown in FIG.

In step n3, if it is determined that some command signal already exists in the memory 15, the process proceeds to step n5, in which the derived command signal switches the crank angle periodic signal. A second command signal M2 indicating
It is determined whether or not it was. The program in Figure 6 is
Since the process starts with the derivation of the first command signal, the process returns from step n5 to the program shown in FIG. is stored, even if the first command signal M1 is derived, the contents stored in the memory will not be rewritten to the derived first command signal M1. Therefore, for example, if the first command signal M1 is When the second command signal M2 to be executed is stored, the stored contents are not rewritten by the newly derived first command signal M1, and the second command signal M2 is reliably executed. A/D of crank angle periodic signal based on
A conversion operation is performed.

The program shown in FIG.
2 is derived. When the program starts, it proceeds to step 1 with a standby determination process shown in the eighth line, and the same process as described above is repeated. In this case, as described above, the process that proceeded to step r15 proceeds to step n6 because the judgment operation was started with the derivation of the second command signal M2, and the process proceeds to step n6, where one of the signals stored in advance is Instead, the derived second command signal M2/''- is rewritten, and the processing returns to the program of FIG. 7 and proceeds to other processing. Therefore, when the second command signal M2 is derived, This ensures that the A/D conversion operation of the crank angle periodic signal is performed while ignoring the execution of the A/D conversion operation of the time periodic signal based on the first command signal M1.

Therefore, according to this embodiment, the A/D conversion operation of the crank angle periodic signal can be reliably executed without being ignored, and the opening/closing control of the fuel injection valve in the internal combustion engine can be optimally performed. can. In addition, it is possible to reliably detect excessive knocking output that can lead to damage in the internal combustion engine, so the internal combustion engine can be appropriately controlled in response to the detection, and damage to the internal combustion engine can be avoided. .

Although this embodiment is described in relation to the output from the knocking sensor as a crank angle periodic signal, this is not a limitation. Also, the second
The command signal is not limited to a signal synchronized with the crank angle.

Effects of the Invention According to the present invention, the analog signal to be converted based on the second command signal can be converted into a digital value and processed without being ignored. Therefore, if the second command signal is a signal that specifies a channel to be switched to perform analog/digital conversion of a crank angle periodic signal, the fuel injection control in the internal combustion engine may be controlled in the 1&appropriate state. control, and furthermore, damage to the internal combustion engine can be avoided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a simplified configuration of an analog/digital converter that is an embodiment of the present invention, FIG. 2 is a timing chart showing the timing of A/D conversion operation of a time periodic signal, and FIG. Figure 3 is a diagram showing the crank angle, Figure 4
The figure is a timing chart showing the timing of A/D conversion operation of a crank angle periodic signal, No. 5 [! 1 is a timing chart for explaining the control operation in this embodiment, FIG. 6 is a flowchart for explaining the A/D conversion operation of a time periodic signal, and 70th is a timing chart for explaining the A/D conversion operation of a time periodic signal. Dg: Flowchart for explaining operation operations, FIG. 8 is a flowchart for explaining judgment operations in standby judgment processing, and FIG. 9 is a timing chart for explaining control operations of a conventional analog/digital converter. , FIG. 10 is a flow chart for explaining the judgment operation of the conventional analog/digital converter, and FIG. 11 is a timing chart for explaining the problems of the conventional method. DESCRIPTION OF SYMBOLS 1... Analog/digital conversion device, 2... Changeover switch, 3... Channel, 6... Analog/digital conversion circuit, 7... Processing circuit, 8... Intake air pressure sensor, 9...・・Water temperature sensor, 10・−・Intake temperature sensor,
DESCRIPTION OF SYMBOLS 11...Battery, 12...Throttle valve opening sensor, 13...Knocking sensor, 14...Peak hold circuit, 15...-Memory, 17...Fuel injection valve, 18...Ignition - Next circuit switch, 19...Crank angle sensor, Ml...First command signal, M2...Second command signal, W3...First time interval, W4...Second
Time interval, w31. w42...Execution period, WB2. W
43...Waiting period Figure 1

Claims (1)

[Scope of Claims] A changeover switch that selects a plurality of analog signals one by one; an analog/digital conversion circuit that converts the output of the changeover switch into a digital value; and a command that indicates a channel to be switched by the changeover switch. a memory for storing signals; a first command circuit for deriving a first command signal to be converted from analog to digital at each predetermined first time interval; and at each predetermined second time interval different from the first time interval. , a second command circuit that derives a second command signal to be converted from analog to digital; and during the continued operation of analog/digital conversion by the analog/digital conversion circuit and/or arithmetic processing based on the analog/digital conversion, a first control means for storing the first command signal in the memory when the first command signal is derived from the first command circuit; and with the first command signal being stored in the memory;
When a second command signal is derived from the second command circuit,
a second command signal for rewriting the stored contents of the memory into a second command signal;
An analog device characterized by comprising: a control means; and a third control means for switching the channel of the changeover switch based on a first command signal or a second command signal stored in the memory after the completion of the continuous operation. /Digital conversion device.