JPS58222304A - Control system using microcomputer - Google Patents

Abstract

PURPOSE:To control effectively an engine of a car, by taking a prescribed time width determined depending on a built-in counter all as the unit of time measurement for applying interruption at each prescribed time. CONSTITUTION:A one-chip microcomputer MC is provided with a CPU1, an RAM2, and ROM3, a counter 4, an input port 5, and an output port 6 and the like. Further, the counter 4 counts a reference clock from a system clock generating circuit and the period of a count-up signal outputted from the counter 4 depends on preset data. A crank angle sensor DET1, an engine cooling water temperature sensor DET2, a suction amount sensor DET3, a ventilation oxygen density sensor DET4, and a car speed sensor DET5 are provided. An interruption is applied at each prescribed time to each sensor output by taking a prescribed time width determined with the counter 4 as the unit of time measurement.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control system using a micro combinator which is applied to engine control of automobiles and the like.

The phycrocombinator (hereinafter referred to as microcomputer) has a central processor unit (OPV), a data storage π-th random access memory (RAM), a program, and other appropriate information. 11
It includes a memory (ROM), a manual port, an output port, and a counter depending on the required IC.

Here, by using one chip microcomputer including one built-in counter, engine control such as electronically controlled carburetor, idle speed control, etc. of automobiles, for example, (1)
Crank angle? (For example, 3 pulse signals are generated for every engine rotation.) The engine rotation speed data is formed by counting the pulse signals t and (2
) The reference pulse t is output based on the ratio between the counted number and the data, and the duty (Du
ty) When performing control 1' including operations such as generating pulses with a controlled ratio, an external counter is required in addition to the above-mentioned built-in counter. For example,
If the built-in counter kit' of the microcomputer is used to form the data in (2) above, an external counter 7 is required to count the number of pulses t in the control described above.

The purpose of the present invention is to use a one-chip microcomputer r with expanded control functions as well as a counter k1gll for the external device.
Our goal is to provide low-cost microcomputer application systems.

According to the present invention, a fixed time width determined by a built-in counter in a microcontroller is used as a unit for all time measurements, and the output of this built-in counter interrupts the program at fixed time intervals, thereby allowing various inputs to be processed. Measurement of pulse period, determination of output pulse duration and period, etc. are performed.

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 1 is a system diagram of an embodiment of a microcomputer application system in which the present invention is applied to engine control of an automobile.

In the same figure, the MO is a one-chip microcontroller made of, for example, HD6805 (product name) 111, and the entire MO is 11! a,,,,fi Ay't:,
Each circuit includes circuits 1 to 6r. l Chip Yacon MO
, l is Of'U and 2 is the pass line BS'i (
mm of unfair information! Only writing and reading are performed, RAM 3 is for programming and appropriate information or writing 1
4 is a counter used as a timer,
5 is an input boat, and 6 is an output boat.

The counter 4 is configured to count a reference clock r supplied from a system clock generation circuit (not shown) provided in the l-chip microcomputer MO. Counter 4 is
There is no particular limit to freezing, but the number of counts in it,
The configuration is such that it is specified by preset data supplied as a pass line B519. Therefore, the period e of the count-up signal output from the counter 4 is determined by the period of the reference clock and the count number specified by the preset data. The count-up signal of the counter 4 is supplied to the OPU 1 as a timer interrupt signal T.

In FIG. 1, D and T to DEIT are, for example, a crank, a steering angle sensor, an engine coolant temperature sensor, an intake air amount sensor, an exhaust M element, a summer sensor, and a vehicle speed sensor, respectively.

The crank angle sensor DOT is coupled to the engine crankshaft and outputs a pulse signal when the crankshaft is at a particular angle π. Although not particularly limited, the crank angle sensor D RT r [, is configured to output three pulse signals per revolution of the crankshaft.

The pulse signal output from the crank angle sensor DgTi includes engine rotation speed information as well as crank angle information. The engine rotation speed information is the period 1 of Melf No. 46 output from the crank angle sensor DJIITl.
! -1 By measuring by executing the program of the chip microcomputer MO or by crank angle sensor D
ET, the number of pulse signals output per unit time t
You can get it by counting.

Crank angle sensor DJ! The crank angle information and engine speed information obtained from lTt are determined by the crank angle, engine,
In order to find the tie-bang that differs from the ignition angle of the gin, it is said that it is necessary to be able to set it in one go, and it is relatively accurate. Therefore, in this embodiment, in order to preferentially process the information sound contained in the output pulse signal of the crank angle sensor DfiT, this output pulse signal is sent to the external interrupt signal E and R to the OPU1. and supplied to optyi.

The engine coolant temperature sensor DIIIT is composed of a temperature sensing element such as a thermistor and a bias resistor R1 for applying a bias current to it, and outputs an analog level voltage corresponding to the engine coolant temperature. .

The intake sensor D[Ts outputs an analog level voltage proportional to the engine intake amount.

The exhaust eIt elementary concentration sensor DEIT4 outputs an analog level voltage proportional to the oxygen concentration in the exhaust gas.

The outputs of these analog sensors DET or DFltT4 are supplied to an analog-to-digital conversion circuit 10.

Vehicle speed sensor DNTIrc, for example, coupled to the output shaft of a car transmission, and configured to detect v411iAI per revolution of the output shaft.
7) Output a pulse signal like this.

Analog-digital conversion #N! to have a sensor D It T z fx lh as required inside it.
It includes a multiplexer for selecting the signal system to be supplied from L D E T 4 . The operation of this circuit 10 is controlled by the board 5 in the l-chip microcomputer MO.
It is controlled by a control signal supplied to the L7 valve.

A digital signal output from this circuit 10 is supplied to the boat 5' via a data line DLI.

The boat 5 includes a latch circuit that is set according to a digital signal supplied from the analog-to-digital conversion circuit 10 and reset by execution of a processing program, and a latch circuit that is similarly set according to a digital signal supplied from the analog-to-digital conversion circuit 10, and a latch circuit that is set according to a digital signal supplied from the analog-to-digital conversion circuit 10 and reset by the execution of a processing program. It includes a latch circuit r that is set by a signal and reset by execution of a processing program.

The output ports in the one-chip microcomputer MO include an inverted number of latch circuits each set or reset by one '1:11 control signal supplied via the pass line B8r.

The output of the output hoard 6 is supplied to appropriate electrical equipment in the engine via a drive circuit DRVI or DRV provided as required.

For example, the output of the drive circuit DRV, is supplied to the ignition coil, the output of the drive circuit DRV, n1 is supplied to the electromagnetic solenoid for intake valve control, and the output of the drive circuit DRYs is supplied to the control of the valve for exhaust gas recirculation. is supplied to the electromagnetic solenoid for.

The supply voltage v0° for the illustrated circuit is formed by a constant voltage circuit Mll which receives a voltage vB12 from battery B.

In this embodiment, the following information processing @l is performed by software using only one internal counter.As a result, the above-mentioned external counter is not required.

(1) 1+ measurement of the period of the pulse signal output from the crank angle sensor DKT.

(2) Needle side of the period of the pulse signal output from the vehicle speed sensor DHT.(3) Control of the period of the output pulse and the pulse length.

FIG. 2 is a timing diagram showing the processing timing of the system of the embodiment shown in FIG. .

In the above information processing, various counter data are stored at appropriate addresses in the RAMZ. When a count-up signal is output from the counter 4 as an interval timer, a timer interrupt request (TLm
When the timer interrupt program (hereinafter referred to as T-R) is entered, the timer interrupt program stored in ROMA in advance is executed. By executing the timer interrupt program, various counter data in RAMZ are updated. FIG. 3 shows a time chart of the execution of the timer interrupt program and the execution of the main program (main routine).

Therefore, the counter data in the RAMZ has a time base (time unit) h determined by the counter 4. For example, the period of 100 output from the counter 4 is R
The counter data to be held in the AMZ can be determined excessively depending on the time unit required. Especially f
The period of the output signal of the counter 4 is assumed to be 160 μ days.

Two addresses are allocated within the RAM 2 for the information processing in (1) above. One of these second addresses is engineering number N, and the remaining one address? Let it be R.

An external interrupt request (Fixtern) is sent to 0PUI by a pulse signal output from the crank angle sensor DET.
al engineering interrupt R@qu6st, hereinafter E
When an external interrupt processing program (referred to as R) is issued, an external interrupt processing program is activated. When the external wt+p write processing program is executed, the contents at address IN of RA-M2 are written into address R, and the contents at address IN are reset to O. Note that the external interrupt processing program includes an instruction for setting flag data indicating the external interrupt processing program in an appropriate address in RAMZ, if necessary.

After the external S interrupt processing program is executed, when the timer interrupt processing program S is executed by the T function outputted from the counter 4, the content in the band process N of the RAM 2 is increased (incremented) by 1. nru.

Therefore, during the period from the crank angle sensor DET until the engine R is output again, the content in the address IN of the RAM 2 is updated to a value b equal to the number of times TIR occurs.7L. In other words, TIJ't occurs once every 160μa, so
Contents in address IN: Crank angle* Nt D Jn
It increases from Tt to a value corresponding to the period of pulse No. 48 outputted.

Crank angle sensor DI! When the external interrupt processing program is executed again by the pulse signal output from tT, the contents of address N in RAM2 are written to address R, and the contents of address IN are written to 0, as in 1iiJ. will be reset. As a result, a value corresponding to the cycle of the crank angle sensor DBTR (D output 7) pulse signal, in other words, an EO value proportional to the engine rotational speed is written in the address R.

The Fi'iJ record information processing@(2) is also carried out in the same manner as the superior information processing 1. In this example, pulse number 13 from the vehicle speed sensor DOT is fed to the latch circuit in the boat 5 in a self-contained manner. Therefore, the latch circuit in the boat 5 is set when a pulse signal is output from the vehicle speed sensor DEIT. For processing vehicle speed data, two addresses are allocated in the RAMZ as described above. Here, it is assumed that one of the above two addresses is ``t'' and the remaining one is ``IM''.

Similarly to the above, when TIR is output from the counter 4, the timer interrupt processing program is executed in response. The timer interrupt processing program determines whether the latch circuit corresponding to the vehicle speed sensor D[Tl in the boat 5 is set or reset.

If the latch circuit is in the set state, the execution of the program following the above determination causes the RAM address
The content in V is increased by l.

The contents at address lV are incremented each time the timer interrupt program is executed during the period when the latch circuit is in the set state. Therefore, the contents in address lV are vehicle speed sensor DJ11. T, is increased toward a value corresponding to the period of the pulse signal output from T.

When the above latch circuit is set, the RAM
The contents of address 20 IV are written to address M, and the contents of address V are reset to zero. The latch circuit in the boat 5 is also reset. As a result, R
In address M of AM2, data with a value proportional to the period of the pulse signal output from the vehicle speed sensor DPIT, in other words, data with a value 7 proportional to the vehicle speed is held.

The information section [(3) can be performed as follows. In the RAM 2, an appropriate address is set for storing the counter data r of the records formed by this information processing (3)K. Therefore, in order to store this counter data, it is assumed that an address n is set in the RAM 2 as T1% T1 and IT.

Although not particularly limited, the address IT& of RAM2 corresponds to the drive circuit DRV, the address T[ corresponds to the drive circuit DRVI, and the address T3 corresponds to the drive circuit DRY.

The timer interrupt processing program includes the information unit 1.
With various instructions for the execution of (1) and (2),
It also includes various instructions t for executing information processing.

By executing the timer interrupt processing program, the RAM
The data in addresses T11, T1 and T3 of No. 2 are each updated by 1. By executing the same program, the updated data in the address lTI is compared with the comparison data written in advance in an appropriate address in RAMZ, and it is determined whether the updated data and the first ratio soft data match. If so, MA# circuit DRV in boat 6 is determined based on this comparison result.

The corresponding latch circuit is set to the set state.

= The updated data within the 17th block of address is stored in RAM.
If the updated data and the second comparison data match, the data in the boat 6 is compared with the second comparison data previously written in an appropriate address in the boat 6. The latch circuit corresponding to the drive circuit DRVI returns to the set state, and the data in the address T1 of the RAM 2 is reset to 0. By this, jlAl
The latch circuit in the boat 6, which corresponds to the lb circuit DRV, outputs the second comparison data for a period of %Flr, that is, after the data in address ITi of RAM 2 reaches a value equal to the first Hiei theta. The set state is maintained only for a period until the values become equal.

RAM2 addressee T! And the count data in T3 is used to control the solenoid. Control operations using such count data may be relatively slow operations. Therefore, although there are no particular restrictions, RA
The routine processing @ which uses the address code T2 of M2 and the count data in ITs is performed by executing the main program (main routine) after executing the timer interrupt processing program.

In other words, by executing the main program, RAM2
0th address engineering T! Inner data or RAM20 appropriate: 11・□・
11 Compare with the third comparison data that has been entered in advance within the address.
l If the comparison results of these data match, then the drive circuit 1I in the boat 6 based on the ratio 11M of the seventh
The latch circuit corresponding to IIDRV is reset. The above address in RAM2 is blurred! The data in the IM is compared with the fixed comparison data convoluted in advance in the ROMa, and if the comparison results of these data match, the drive in the boat 6 is changed based on the comparison result. The launch circuit corresponding to circuit DRV is set, and the data at address T of RAM2 is reset (HC).

Therefore, the latch circuit corresponding to the drive circuit DRV is
1 of the pulse period determined by the above fixed comparison data
Among the Ayan periods, the period determined by the third comparison data is set.

The reset data in the address code T3 is sequentially updated by executing the timer interrupt processing program again.

Is there no particular restriction, or is there fixed comparison data in Figure 2?
1J, that is, one period of the pulse signal output from the latch circuit in the boat 6, or 160μs
160 (=25.6ms).

The data in RAM 20 address lTl is processed by the same procedure as the data in address T.

The latch circuit corresponding to the drive circuit DRVg is configured to perform one cycle of the pulse period determined by the fixed comparison data.
It is written into an appropriate address in RAM 2, and 7 is kept in a set state for a period determined by the fourth comparison data.

The main program is analog sensor DffiT.

Alternatively, the analog level voltage t outputted from DjnT4 is converted into a digital signal by the analog-to-digital conversion circuit 10, and then stored in the RAM 20 at an appropriate address.
1. Contains a program to be loaded.

The main program also includes a program for converting the first to fourth ratios into an r-shaped base.

ROM 3RI, FI control engine characteristics are determined by the characteristics of the engine and are included in the NB% performance data. For example, engine tJM
In order to achieve proper operating conditions, it is necessary to provide an appropriate ignition advance angle. This ignition advance angle is considered to be a function of engine rotational speed and engine temperature (engine coolant storage).Therefore, in ROMA, the engine rotational speed vs. ignition timing data is stored in the control device depending on the engine. It is written for each engine level.In addition, the RO
Engine characteristic data to be held in Ma is ROM
In order to prevent an increase in the storage capacity of 3, sampling values are taken at discrete intervals. The required data between the sampled values is formed by interpolation operations by executing the program.

Therefore, by executing the main program, for example, the first comparison data is formed as follows.

In other words, it refers to the actual engine temperature data and engine speed data written in RAMZ, and corresponds to two engine temperature sampling values and engine speed values that are close to the actual temperature data and engine speed data. Two ignition timing data can be read from ROM3. Two read ignition timing data vfil
i11. By interpolating the data, timing data is formed that passes through the actual engine temperature and engine speed. Is this tying data #Il ratio 11Rf-
In the evening, 41 is written into RAMZ.

The second comparative soft data is the constant data r
It is formed by adding.

The ignition coil (not shown) connected to the drive circuit DRVI generates a pulse signal from the crank angle sensor D]1iT while the latch circuit in the boat 6 corresponding to the drive circuit DRY is set. The engine is activated for a predetermined period after the period specified by the ignition timing data has elapsed.
Similarly, the third comparison data is formed by data such as engine hot water temperature and engine speed versus intake pulp control data written in ROMa and appropriate interpolation calculations.

This MAI is connected to the third electromagnetic solenoid that moves the intake valve (not shown) connected to
While the latch circuit in the boat 6 corresponding to the Jh circuit DRV is set, that is, l period 1 as described above.
60p8x160 The drive current is passed for each nrt period as instructed by the second ratio data. Therefore, the average value of the drive flow flowing through the electromagnetic solenoid is proportional to the value of the second comparison data. The mechanical force output from the electromagnetic solenoid is proportional to the value of the second comparison data. As a result, the valve opening degree of the intake valve corresponds to the second comparison data.

The fourth comparison data is formed by a similar method. The exhaust gas recirculation valve is driven by an electromagnetic solenoid (not shown) coupled to the drive circuit DRV3, and the opening degree of the valve is made into a π value in correspondence with the fourth comparison data.

In this embodiment, the conditions for the above-mentioned process to become practical are as follows: a constant value of the microcomputer's command execution time counter (interval timer) < width of one cycle of pulse input and pulse output.

Also, the pulse xON of the pulse signal output from the boat 6
The width and pulse period are integral multiples of the value of counter 4 (interval i<timer).

Main routine, a-R routine, f in separate processing
A flowchart of the f1IR routine is shown in Figure #44.

In the system described above, the timer interrupt is limited to 160 μ8, or in the system of the present invention, the timer interrupt register 1
By setting t to an arbitrary value, the interrupt time can be set arbitrarily. Therefore, even if the pulse period is considerably long, for example, when data is in an 8-bit configuration, it can be handled. According to the present invention, for example, it is possible to arbitrarily set the engine rotational speed of an automobile in an idling state by controlling an auto choke using the system of the present invention.

Note that the present invention is not limited to automobiles and can be applied to other fields as well.

As explained above, according to the present invention, by using a built-in counter (interval timer) as a unit of time measurement, a built-in counter (interval timer) is used as a unit of time measurement, and by interrupting at regular intervals, it is possible to Since it is possible to measure the period and set the width and period of the output pulse, input/output pulse processing and external connection can be performed without a counter, thereby providing a low-cost microcomputer application system. In particular, the processing means is useful for automobile engine control because it can be executed in the same way regardless of the number of pulse inputs and pulse outputs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a microcomputer system for use in an automobile according to the present invention, FIG. 2 is a diagram showing the processing timing of the embodiment of FIG. 1, and FIG. 3 is a diagram for explaining an interrupt. FIG. 4 is a flowchart of the main routine, TIR routine, and E/R routine. Figure 2 Figure 3

Claims (1)

[Claims] A control system using a computer having an OPυ, a RAM, a ROM, an input/output board, and 1.0 counters, the control system comprising: a constant time period determined by the counters; It is a unit of time measurement and has a means for measuring the period of input pulses and setting the duration and period of output pulses by interrupting at regular intervals.
tlllJ using a featured microcomputer
ll sis f l-0