JPH05141303A - Control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To accurately seize a noise generating timing at a starter starting time and at a stopping time by limiting a noise generating period by means of a starter starting signal, and carrying out treatment to a sensor signal. CONSTITUTION:In a reference position signal 202 of which a cylinder discriminating signal 201 generated from a cylinder discriminating sensor is generated from a magnetic sensor, both sensor signals 201 and 202 are inputted to a gate array 403 after passing through waveform shaping circuits 401 and 402. A starter signal 405 is also inputted to a microcomputer 404. While using the starter signal 405 as a noise generating period detecting signal, the sensor signals 201 and 202 are detected for the first time as normal signals after a prescribed period immediately after a starter is started. By changing a filter constant to sensors for a prescribed period after the starter starting is finished, a turbulence of a signal waveform caused by noise can be prevented. Thereby, a noise generating timing at a starter starting time and at a stopping time can be seized accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine capable of preventing malfunction due to starter noise generated during cranking and realizing good engine starting.

[0002]

2. Description of the Related Art In a magnetic crank angle sensor that magnetically detects engine rotation or a specific crank angle,
The sensor output is determined by the amount of change in the magnetic flux density across the coil. When the amount of change in the magnetic flux density is the same, the output increases as the number of coil turns increases, so in order to secure sufficient signal output even when the rotational speed at startup is low, such as cold start. It is necessary to secure the signal output by increasing the number of turns of the coil. However, at start-up, a large amount of current is required to rotate the starter, and this current flows through a magnetic material near the sensor, causing a magnetic change, and the magnetic sensor erroneously detects this change and engine control at start-up occurs. There was the problem of going crazy. To solve such a problem, Japanese Patent Application No. 2
As described in JP-A-96557, after detecting a signal from a magnetic sensor, a signal is ignored or a filter constant is changed for a certain period.

[0003]

However, in such a method, since the generation timing of noise is not accurately grasped, the signal is ignored even for the regular sensor signal, which causes an increase in the starting time. In addition, there was a problem that it was not possible to deal with the noise generated at the end of the starter operation.

[0004]

In order to solve this problem, the period of noise generation is limited by the starter start signal and the sensor signal is processed.

[0005]

The starter start signal is used as a noise generation period detection signal, and the sensor signal is detected as a regular signal only after a predetermined period immediately after the starter is started. It is intended to prevent the disturbance of the signal waveform due to.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A system configuration of an embodiment of the present invention will be described based on FIG. This embodiment is a 4-cylinder engine. An ignition coil 4 is installed in the engine 1 for each cylinder. The cylinder discrimination sensor 2 is directly connected to the cam shaft. In addition, the ring gear 8 connected to the crankshaft has the pin 7 at the reference position.
Are set, and the magnetic sensors 5 and 6 are installed with a gap of about 1 mm from the gear 8 and the pin 7, respectively. When the engine 1 starts to rotate, the sensors 2, 5 and 6
Produces the signal shown in FIG. In FIG. 2, 201 is a cylinder discrimination signal generated by the sensor 2, 202 is a reference position signal generated by the sensor 6, and 203 is an angle signal generated by the sensor 5. These signals correspond to the unit 10 of FIG.
The unit 10 sends a signal to the power transistor 9 for the ignition timing and the cylinder position determined from this signal and other signals. In response to this signal, the power transistor 9 cuts off the current of the corresponding ignition coil 4 and ignites for each cylinder. Also, cylinder discrimination is
This is performed by measuring the number of signals 201 input while the signals 202 are generated.

The configuration and flow chart of the present invention will be described below. FIG. 4 is a block diagram of the present invention, in which the reference position signal 202 and the cylinder discrimination signal 201 are the waveform shaping circuit 4
After passing through 01 and 402, it is input to the gate array 403. The gate array 403 counts the number of cylinder discrimination signals 201 generated during the reference position signal 202 and sends a one-cylinder signal to the microcomputer 404 every time the first cylinder is discriminated. A starter signal 405 is input to the microcomputer 404, and a cylinder discrimination mask signal 406 and a filter constant change signal 407 are output from the microcomputer 404. The mask signal 406 generates either a HIGH signal or a LOW signal, the gate array prohibits cylinder discrimination when the HIGH signal is generated, and permits the cylinder discrimination when the LOW signal is generated.

Similarly, the filter constant change signal is also HI.
Generate a signal of either GH or LOW, and filter 40
1 operates so that, when receiving a HIGH signal, the filter passes a signal on a lower frequency side than the normal frequency.

FIG. 5 shows a flow for controlling the functions of this block diagram. This process is activated by a time interrupt every 5 ms.

First, the generation of the noise signal will be described. The noise generated by the starter signal 405 is generated near the time when the starter is activated and the pinion gear meshes with the ring gear as shown in FIG. This is because a large current flows through the starter because the torque required for engagement and the torque required for rotating the ring gear immediately after engagement are large, and this causes a magnetic field change of the magnetic sensor, which causes a noise signal. Similarly, the current that was flowing until then suddenly stopped when the starter stopped. The magnetic sensor picks up noise. As shown in FIG. 3, this timing is around 30 to 40 ms after starting the starter at room temperature, and this time, that is, the time when the pinion gear rushes into the ring gear, changes depending on the engine temperature at the time of starting.

The noise generated when the starter is stopped is generated within about 10 ms after the starter is stopped.

The flow of FIG. 5 is required to prevent malfunction due to this noise.

In step 501, it is judged whether or not there is a change in the signal level of 405 at the time of passing this flow last time and the state of the current 405. If a change is detected, the process proceeds to step 514 and the current starter signal 405
Check whether the status is ON (HIGH status) or OFF (LOW status). If it is ON here, the process proceeds to step 515, the ST1 flag is set, it is stored that the cylinder discrimination prohibit mode is entered, and the process proceeds to step 517. If the state of 405 is OFF in step 514, ST in step 516.
After setting the 2 flag and memorizing that the filter constant changing mode has been entered, the routine proceeds to step 517. Step 51
At 7, the state of the starter signal 405 is stored and this flow ends. When the state change of the starter signal 405 is not recognized in step 501, it is checked in step 502 whether the ST1 flag is set, and if it is set, it is checked in step 509 whether the timer 1 is larger than a. In addition, a is a constant selected according to the engine water temperature. When the timer 1 is less than a in step 509, the timer 1 is incremented in step 510, the cylinder discrimination mask output 406 is set to HIGH in step 511, and the gate array is prohibited from performing cylinder discrimination.

If the timer 1 is equal to or greater than "a" at step 509, it means that the cylinder discrimination prohibition time has expired, so the ST1 flag is cleared at step 512, and step 513
After the cylinder discrimination mask output 406 is set to LOW, the process proceeds to step 517.

When ST1 is not set in step 502, it is determined in step 503 whether ST2 is set. If not set, step 51
If it is 7, the process proceeds to 504 and it is checked whether the timer 2 is b or more. Step 50 if timer 2 is less than b
5, the timer 2 is incremented, the filter constant change output 407 is set to HIGH in step 506, and the process proceeds to step 517. When the output 407 is HIGH, as described above, the design is such that the characteristics of the filters 401 and 402 can be changed to a low frequency that does not allow starter noise to pass. When the timer 2 becomes equal to or more than the predetermined value b in step 504, the filter 401,
Since it is not necessary to set the characteristic of 402 to the low frequency side, the ST2 flag is cleared in step 507, and step 50
In step 8, the output 407 is set to LOW and the process proceeds to step 517 to end this flow. By having such a control logic, it is possible to perform effective processing only at the time when noise is generated, so it is possible to change the filter characteristics significantly without impairing startability. It is possible to minimize.

It is also an effective means to make the operation of the gate array when the signal 406 is HIGH mask the cylinder discrimination signal 201 or the reference position signal 202.

[0017]

According to the present invention, the timing of noise generation during start-up and stop of the starter can be accurately grasped, and noise prevention measures can be taken only at this timing. Therefore, the control is highly effective and does not impair startability. Can be supplied.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of the present invention.

FIG. 2 is a signal diagram.

FIG. 3 is a diagram showing a starter noise occurrence period.

FIG. 4 is a processing block diagram.

FIG. 5 is a signal processing flowchart.

[Explanation of symbols]

1 ... Engine, 2 ... Cylinder discrimination sensor, 3 ... Injection valve, 4 ...
Ignition coil, 5 ... Angle sensor, 6 ... Reference position sensor, 7
... reference position detection pin, 8 ... ring gear, 9 ... power transistor, 10 ... unit, 11 ... water temperature sensor.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location F02D 45/00 C 8109-3G F02P 5/15 E 9150-3G

Claims (4)

[Claims] 1. A cylinder discriminating sensor for discriminating a cylinder of an internal combustion engine and a reference position detection sensor signal for discriminating a reference position of each cylinder are used for engine control. The two signal outputs are crankshaft or camshaft rotation. Which is detected by a sensor that magnetically detects the internal combustion engine, wherein the sensor signal is not used for engine control for a predetermined period immediately after the start of cranking. 2. A control device for an internal combustion engine according to claim 1, wherein the predetermined period can be set by an engine water temperature. 3. Engine control is performed by a cylinder discrimination sensor for discriminating a cylinder of an internal combustion engine and a reference position detection sensor signal for discriminating a reference position of each cylinder, and the two signal outputs are crankshaft or camshaft rotation. Which is detected by a sensor that magnetically detects the internal combustion engine, wherein the filtering frequency for the sensor signal is set low for a predetermined period immediately after the end of cranking. 4. The control device for an internal combustion engine according to claim 1, wherein the predetermined period can be set by an engine water temperature.