JPH0763108A - Electronic controller of internal combustion engine - Google Patents

Abstract

PURPOSE:To provide the electronic controller of an internal combustion engine capable of decreasing process load at high rotation without deteriorating quality of control. CONSTITUTION:It is judged whether a brand new engine rotational speed NE calculated previous by at S2 is more than 2500rpm (second judgement value) or not, namely whether it is high rotation for increasing process load or not, and if it is judged at the high rotation, process for seeking for an engine stall judgement counter CENATB for low rotation at S3 is skipped so as to decrease the process load. It is judged whether rotational speed NE is more than 1000rpm (first judgement value) or not at S9. When it is judged at high rotation, since the process load at the high rotation is large with no margin for precessing, used pulses are remarkably pruned by the process of S17-S23, and 360 CA time (T360) is found over, and rotational speed is calculated based on the T360.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic control device for performing various controls in an internal combustion engine, and more particularly to an electronic control device for an internal combustion engine capable of reducing the load on the CPU at high rotation speeds.

[0002]

2. Description of the Related Art Conventionally, in an electronic control unit (ECU) of an internal combustion engine (engine), in order to perform fuel injection according to the crank angle position of the engine and to calculate the engine speed from the interval of the pulser, Real-time interrupt processing is performed by the pulsar signal.

As the general interrupt processing by the pulsar signal, a processing for calculating a pulse interval time from the interrupt time, a determination processing for detecting a missing tooth which is a reference position of the pulsar signal, and a fuel injection amount There are processes for calculating a reference time (for example, 360 ° CA, 90 ° CA time) for controlling the injection timing, the engine stall determination process, and many other control processes. Then, normally, in the engine control ECU, processing for many of these controls is performed.
It is performed in the interrupt process performed every time the pulser signal is input.

[0004]

However, when the interrupt processing is performed using the pulser signal as described above, there are the following problems. For example, processing of engine speed and detection of missing teeth requires the same amount of processing regardless of low speed or high speed, so the processing load ratio is low at low speed, but the processing load ratio becomes higher as the speed increases. There is the problem of becoming expensive. In particular, when the rotation speed becomes high and the rotation speed exceeds a certain rotation speed (limit rotation speed) determined by the processing amount and the number of teeth of the pulsar, the processing load ratio exceeds 100%, and the CPU capacity may be exceeded. Conceivable. On the other hand, it is conceivable to reduce the processing amount itself and increase the limit rotation speed, but it is not possible to omit the necessary processing,
A major problem was how to reduce the processing load rate.

As a countermeasure against this, a technique has been proposed in which the frequency of calculation is reduced by thinning the number of times the fuel injection amount is calculated as the engine speed increases, but this alone does not reduce the quality of the control. Is difficult to sufficiently reduce (see Japanese Patent Application Laid-Open No. 1-116270).

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electronic control unit for an internal combustion engine which can reduce the processing load at high rotation speed without degrading the quality of control.

[0007]

As shown in FIG. 1, the present invention for achieving the above object calculates a rotation speed by using pulse data of a sensor generated according to rotation of an internal combustion engine. , An electronic control of an internal combustion engine that sets an engine stop determination counter value used for engine stop determination using the pulse data, and compares the engine stop determination counter value with a predetermined engine stop determination value to determine engine stop In the device, when the rotation speed of the internal combustion engine is determined to be higher than the first determination value by the first determination means and the first determination means for determining the rotation speed of the internal combustion engine using a first determination value. Is a rotation speed calculation means for high rotation, which captures the pulse data at a frequency lower than that when the rotation speed is low, and a high rotation speed of the internal combustion engine. A second determination unit that determines by using a second determination value that is equal to or greater than a first determination value, and if the second determination unit determines that the rotation speed is higher than the second determination value, An electronic control of an internal combustion engine comprising: an engine stalling determination counter setting unit that sets the engine stalling determination counter value by using low-frequency pulse data used for calculating the engine speed by the engine speed calculating unit. The device is the gist.

[0008]

In the present invention, the engine speed is calculated using the pulse data of the sensor generated according to the rotation of the internal combustion engine, and the engine stall counter value used for the engine stop judgment is set using the pulse data. The engine stop determination is performed by comparing the engine stall determination counter value with a predetermined engine stop determination value.

Then, the first determination means determines whether the rotation speed of the internal combustion engine is high or low using the first determination value,
Here, when it is determined that the rotation speed is higher than the first determination value, the high rotation speed calculation means fetches the pulse data at a lower frequency than when the rotation speed is low, and calculates the rotation speed. . Further, the second determination means determines whether the rotation speed of the internal combustion engine is high or low using the second determination value,
Here, when it is determined that the rotation speed is higher than the second determination value, the low frequency pulse data used for the calculation of the rotation speed by the high rotation speed calculation means is used, and the engine stop determination counter setting means is used. , Set the engine stall judgment counter value used for engine stop judgment.

That is, in the present invention, when the engine speed is high and the engine stall is determined, when the engine speed is high, the engine stall determination is performed by using the data used to calculate the engine speed when the engine speed is high. Because it is possible to
The processing load at high rotation speed is reduced.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a schematic configuration diagram showing a system configuration of an electronic control unit for an internal combustion engine according to an embodiment of the present invention. As shown in FIG. 2, a pulsar 5 having teeth 4 arranged at equal intervals (including a missing tooth) is attached to a crankshaft 2 of an engine 1. The pulse interval and the number of missing teeth of the pulsar 5 can be arbitrarily set according to the system configuration, but in the present embodiment, seven teeth 4 corresponding to the values “0” to “6” of the pulse counter CNIRQ described later are provided. Is arranged and a missing tooth is set at the eighth position.

In addition, the sensor 6 is placed close to the teeth 4 of the pulsar 5.
The sensor 6 is connected via a waveform shaping circuit 7 to an electronic control unit (ECU) 8 configured as a microcomputer. The ECU 8 includes a known CPU 8a, ROM 8b, RAM 8c, input / output port 8d, bus 8e, etc., and the waveform shaping circuit 7 is connected to the input / output port 8d.

In the present embodiment, as shown in FIG. 3, the rotation of the pulsar 5 causes the sensor 6 to output the waveform of the signal A to the waveform shaping circuit 7, and the waveform shaping circuit 7 then outputs the signal B. Is shaped into the waveform of. Therefore,
The pulse counter CNIRQ is cleared for each missing tooth (that is, for each rotation) in response to the fact that the pulse for the missing tooth portion is not generated, and the actual tooth 4 portion changes from "0" to "6". It will be counted up.

Next, the control processing of this embodiment having the above-mentioned configuration will be described with reference to the flow charts of FIGS.
Here, FIG. 4 is an interrupt process performed every time a pulse is generated, FIG. 5 is an interrupt process for updating various counters performed every 5 ms, and FIG. 6 is an interrupt process performed every 10 ms. 7 is a rotation speed calculation process performed in the main routine.

First, a pulse interruption process performed every time a pulse is generated for determining the number of revolutions will be described with reference to FIG. As shown in FIG. 4, first, in S1, the interrupt interval (time) is calculated by subtracting the previous interrupt time from the current interrupt time.
And store the value in the register Yreg.

At S2, it is determined whether or not the latest engine speed NE calculated last time is 2500 rpm (second determination value) or more, that is, whether or not the processing load is high rotation. If it is determined to be rotation, the process proceeds to S7, which will be described later, and if it is determined to be low rotation, the process proceeds to S3.

At S3, since the processing load is low and the rotation speed is low, the value of the engine stall counter CENST is set to the value of the engine stall determination counter CENSTB used for the engine stop determination (engine stall determination). The engine stall counter CENST is, as shown in FIG. 5, incremented in S100 by an interruption process of 5 ms. When it is determined in S101 that the engine stall counter CENST exceeds 500 ms, 500 ms is set as a guard value in S102.

On the other hand, the engine stall judgment counter CENSTB
Is used for engine stall determination in the case of low rotation. That is, as shown in FIG. 6, in S201, the rotation speed N
When E is determined to be 2000 rpm or less, the engine stall determination counter CENSTB is compared with a predetermined (for low rotation) engine stall determination value in S202 to determine the occurrence of engine stall.

The reason why the engine stall can be detected by this determination is that the engine speed NE of the engine 1 decreases when the engine stall occurs, so that the interval of the pulse interruption in FIG. Since the value of the engine stall counter CENST (that is, the engine stall determination counter CENSTB) that is incremented every 5 ms of 5 increases, it can be determined that an engine stall has occurred when the engine stall determination counter CENSTB becomes larger than the engine stall determination value. You can do it.

Returning to FIG. 4, the engine stall counter CENST is cleared in S4. In subsequent S5, it is determined whether or not the engine stall determination counter CENSTB exceeds 60 ms, and if it is determined that it exceeds 60 ms, a guard value is entered in the register Yreg (in order to prevent overflow) in S6. And proceed to S7. On the other hand, if it is determined that the time is 60 ms or less, the process directly proceeds to S7.

In S7, the register Yreg which is the interrupt interval is set.
Is set to the value of TNINT. In addition, this TNIN
Since T indicates the interval between pulses, it is used for various other processes such as fuel injection control. In subsequent S8, the present interrupt time is set as the previous interrupt time in order to obtain the next interrupt interval.

That is, in the processes of S2 to S6, when the rotation speed NE is lower (lower than the second determination value), the engine stop determination counter CENSTB for low rotation is set, but when the rotation speed NE is high, it is set. , Engine stall counter CENST
This is a process for reducing the processing load by omitting the step of setting B.

Then, in the subsequent S9, the rotational speed NE is 10
It is determined whether or not it is 00 rpm (first determination value) or more, that is, whether or not it is high rotation. If it is determined that the engine speed is high, the process proceeds to S17, which will be described later. If it is determined that the engine speed is not high, the process proceeds to S17.
Go to 10. The determination level of the rotational speed NE in S9 (first determination value = 1000 rpm) is lower than the determination level of S2 (second determination value = 2500 rpm), but this is due to the nature of engine stall determination and rotational speed calculation. It is due to the difference.

In S10, it is determined whether or not the pulse counter CNIRQ is an even number. If an affirmative determination is made here, the process proceeds to S11, and if a negative determination is made, the process proceeds to S24, which will be described later. That is, this determination is made for each pulse in FIG. 3 (that is, 45 ° CA).
This is for performing the following processing every other pulse (every 90 ° CA) in order to reduce the processing load (although it is low rotation) instead of every time.

In S11, the value of the counter C90, which is incremented every 5 ms in S106 of FIG. 5, is set to the value of the judgment counter C90B, and in S12,
The counter C90 is cleared. In the following S13, it is determined whether or not the determination counter C90B exceeds 60 ms, and if it is determined that it exceeds 60 ms, the process proceeds to S16, and if it is determined that it is 60 ms or less, the process proceeds to S14.

In S16, 90 used for calculating the rotation speed.
1/2 of the pulse counter CNIRQ, which is the CA time
The guard value is inserted into the value T90 (n) in. on the other hand,
In S14, a similar value T90 (n) is set to a value obtained by subtracting the current interrupt time from the 90 ° CA interrupt time. By this, the 90 ° CA interval (time), that is, the time every other pulse can be obtained.

In subsequent S15, the current interrupt time is set as the 90 ° CA interrupt time in order to obtain the next T90 (n). That is, in the processes of S10 to S15, since the rotation speed NE is low (than the first determination value), the processing load is small, and there is a margin in processing, in order to accurately calculate the rotation speed NE (see FIG. 7). Used) 90 ° CA every other pulse
This is a process for obtaining the time (T90 (n)).

The process shown in FIG. 7 is a rotation speed calculation process in the main routine. In S601, it is determined whether the rotation speed NE is a low rotation speed of 1000 rpm or less. Is the above-mentioned 90 ° CA in S602.
This is a process of calculating the rotational speed NE by using T90 (1) to T90 (4) which are times. Specifically, each time T9
The half of the average of 0 to T90 is taken as the time of the pulse interval, and the value obtained by multiplying this time by 8 is taken as the time for one rotation to obtain the rotational speed NE.

Returning to FIG. 4, in S24 that follows, a general process such as a missing tooth process and other processes such as a spill valve process is performed, and the present process is temporarily terminated. The missing tooth process is a process of clearing the pulse counter CNIRQ when the currently detected pulse interval is longer than the previously detected pulse interval as shown in FIG. As a result, the pulse counter CNIRQ
The value of is changed from "6" to "0".

Further, in S17, when it is judged that the rotation speed is high, the pulse counter CNIRQ is set to 6 in S17.
It is determined whether or not (that is, one rotation has been performed). If an affirmative determination is made here, the process proceeds to S18, and if a negative determination is made, the above-described S2 is performed.
Go to 4. In other words, this determination is performed at a high rotation speed, and therefore, not at each pulse (that is, every 45 ° CA) in FIG. 3, but every rotation (every 360 ° CA) in order to greatly reduce the processing load.
In addition, it is for performing the following processing.

In S18, the value of the counter C360 that is incremented every 5 ms in S103 of FIG. 5 is set to the value of the determination counter C360B, and in S19, the counter C360 is cleared. In the following S20,
It is determined whether or not the determination counter C360B exceeds 60 ms. If it is determined that it exceeds 60 ms, the process proceeds to S23, where 6
If it is determined to be 0 ms or less, the process proceeds to S21.

At S23, the value used for calculating the rotation speed is 36.
The guard value is put in the value T360 corresponding to 0 ° CA time. On the other hand, in S21, a similar value T360 is set to a value obtained by subtracting the current interrupt time from the 360 ° CA interrupt time.
By this, the 360 ° CA interval (time), that is, the time for one rotation is obtained.

In S22, the current interrupt time is set as the 360 ° CA interrupt time in order to obtain the next T360, and the process proceeds to S24. In other words, in the processing of S17 to S23, since the rotation speed NE is high (than the first determination value) and the processing load is large and there is no processing margin, the pulses to be used are thinned out and 360 ° CA time (T360). Is a process for obtaining.

Then, by using this value of T360, FIG.
In the rotation speed calculation processing in the main routine shown in, first,
In S601, it is determined whether the rotation speed NE is a low rotation speed of 1000 rpm or less, and if it is a high rotation speed, S60
In step 3, set T360, which is the 360 ° CA time described above, to 1
The rotation speed NE is calculated as the time required for rotation.

As described above, in the present embodiment, when the rotation speed NE is a low rotation speed lower than the first determination value, the rotation speed NE is accurately calculated using many pulse timings every 90 ° CA. be able to. On the other hand, when the rotation speed NE is a high rotation speed equal to or higher than the first determination value, the processing load can be reduced and the rotation speed NE can be calculated by using a small pulse timing every 360 ° CA. Further, when the rotational speed NE is equal to or smaller than the second determination value which is larger than the first determination value, the engine stall determination counter CENSTB for low rotation is set, so that the engine stall can be accurately detected in the case of low rotation. On the other hand, when the rotation speed NE exceeds the second determination value, the engine stall determination is performed using the counter C360B used for calculating the rotation speed for high rotation, so that the high rotation speed is maintained without impairing the accuracy of engine stall detection. The remarkable effect that the processing load in the can be reduced.

Next, in the flow charts of FIGS. 8 and 9,
The reduction state of the processing load according to the present embodiment will be shown in comparison with the conventional example. Note that FIG. 8 shows the processing of FIG. 3 in a simplified manner, and FIG. 9 shows a conventional example, in which the number of steps of instructions required in each processing stage is shown.

As is apparent from FIGS. 8 and 9, in the case of high rotation (for example, 5000 rpm), in this embodiment of FIG.
Since S703, S707, and S708 are omitted, the total number of steps of instructions required for processing is as small as 102. On the other hand, in the case of the conventional example of FIG. 9, the number of steps of instructions is 121 in total, which is not preferable.

Although the embodiment of the present invention has been described above, the present invention is not limited to the embodiment, and it goes without saying that the present invention can be implemented in various modes.

[0039]

As described above, according to the present invention, when the engine speed is calculated and the engine stall is determined, when the engine speed is high, the data used for calculating the engine speed is used when the engine speed is high. Since it is possible to determine the engine stall, it is possible to reduce the processing load at high rotation speed without lowering the accuracy. As a result, it is possible to prevent an adverse effect on the CPU due to an excessive increase in processing.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating a configuration of the present invention.

FIG. 2 is a block diagram showing the system configuration of the present embodiment.

FIG. 3 is an explanatory diagram showing signals A and B and a pulse counter.

FIG. 4 is a flowchart showing a pulse interrupt process.

FIG. 5 is a flowchart showing an interrupt process of incrementing a counter.

FIG. 6 is a flowchart showing an interrupt process of an engine stall determination.

FIG. 7 is a flowchart showing a process of detecting a rotation speed.

FIG. 8 is an explanatory diagram showing an effect of the present embodiment.

FIG. 9 is an explanatory diagram showing the number of steps in a comparative example.

[Explanation of symbols]

 1 ... Engine 4 ... Tooth 5 ... Pulsor 6 ... Sensor 8 ... Electronic control unit (ECU)

Claims (1)

[Claims] 1. A rotation speed is calculated using pulse data of a sensor generated according to rotation of an internal combustion engine, and an engine stall determination counter value used for engine stop determination is set using the pulse data, In an electronic control unit for an internal combustion engine that compares an engine stall determination counter value with a predetermined engine stop determination value to determine engine stop, a first determination value is used to determine whether the rotational speed of the internal combustion engine is high or low. 1 determination means and the first determination means, when the rotation speed is determined to be higher than the first determination value, the pulse data is fetched at a lower frequency than when the rotation speed is low, A high rotation speed calculation means for calculating a high rotation speed; a second judgment means for judging whether the rotation speed of the internal combustion engine is high or low using a second judgment value equal to or higher than the first judgment value; If the determination unit determines that the rotation speed is higher than the second determination value, the engine frequency is reduced by using the low-frequency pulse data used to calculate the rotation speed by the high rotation speed calculation unit. An electronic control unit for an internal combustion engine, comprising: an engine stall determination counter setting means for setting a determination counter value.