JPH0637869B2 - Ignition timing control device for internal combustion engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ignition timing control device for an internal combustion engine (hereinafter referred to as “engine” as necessary).

[Conventional technology]

Conventionally, in an internal combustion engine, a reference ignition timing is determined according to its operating state (engine load state or engine speed state), and control is performed based on this reference ignition timing.

In addition, when knocking (knock) occurs, in order to avoid it, the retard control amount (retard amount) is determined, this retard amount is subtracted from the reference ignition timing, and the ignition is retarded. You are in control.

By the way, in an engine equipped with a supercharger (supercharged engine), in order to prevent an abnormal retardation caused by noise picked up by a knock sensor, an upper limit value (for example, 1
0 °) is set. Here, the upper limit value is determined in consideration of a knock limit change due to a change in the environment and a change with time of the engine.

[Problems to be solved by the invention]

However, when this supercharged engine is equipped with a water-cooled intercooler, if water leakage occurs in the water-cooled intercooler and the internal water is drained, this is enough.
The knock limit value changes at about °. That is, the conventional knock control has a problem that it is difficult to achieve both original knock prevention and abnormal retardation prevention due to noise or the like.

The present invention is intended to solve such a problem, and a knock control system having a slow response is added to a conventional knock control system having a fast response, and for example, water of a water-cooled intercooler is drained. An object of the present invention is to provide an ignition timing control device for an internal combustion engine, which can prevent knocking and prevent abnormal retardation caused by noise or the like even when an abnormal situation occurs.

[Means for solving problems]

Therefore, the ignition timing control device for an internal combustion engine of the present invention includes a reference ignition timing determination means for determining a reference ignition timing according to the operating state of the internal combustion engine, and a knock sensor for detecting knock of the internal combustion engine, Knock determination means for determining whether or not a knock has occurred based on the output of the knock sensor; first delay angle control amount determination means for determining a new first retard angle control amount based on the output from the knock determination means; A first retard amount control means for limiting the retard control amount to a predetermined upper limit value, and a new second retard amount when a state in which the first retard control amount is limited to the upper limit value continues for a predetermined period or longer. Second to determine the angular control amount
It is characterized in that a retard angle control amount determining means and an ignition timing calculating means for determining a desired ignition timing from the reference ignition timing, the first retard angle control amount and the second retard angle control amount are provided.

[Work]

In the above-described ignition timing control device for an internal combustion engine of the present invention, the reference ignition timing determination means determines the reference ignition timing according to the operating state of the internal combustion engine, and knock determination is performed based on the output of the knock sensor to determine whether knock has occurred. The first retard angle control amount determining means determines a new first retard angle control amount based on the output of the means, and the first retard angle control amount is set to the first retard angle control amount in order to prevent an abnormal retard angle against noise or the like. The state in which the first retardation amount regulation unit limits the predetermined retardation amount to the predetermined upper limit value and the first retardation amount regulation unit limits the first retardation control amount to the upper limit value for a predetermined period or more, that is, a normal knock or In an abnormal situation where a state that cannot be caused by noise or the like continues, for example, in an abnormal situation where water of a water-cooled intercooler runs out, retard control is performed by the second retard control amount in addition to the first retard control amount, and the above reference ignition timing is set. , First retard system Desired ignition timing from the amount and the second retard control amount is determined, the control signal on the basis of the ignition timing information is output.

〔Example〕

An ignition timing control device for an internal combustion engine as an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 (a) is a block diagram of its main part, and FIG. 1 (b) is a block diagram showing its overall configuration. FIG. 1 (c) is an overall configuration diagram of an internal combustion engine having the present device, FIGS. 2 to 4 are flow charts for explaining the operation, and FIG. 5 is a timing chart for explaining the operation. is there.

As shown in FIG. 1 (c), an engine (internal combustion engine) E having this device has a turbocharger 1 and
A water-cooled intercooler 3 is provided in the intake passage 2.

Reference numeral 4 in FIG. 1 (c) indicates an electromagnetic fuel injection valve (injector), 5 a throttle valve, 6 an air cleaner, and 7 a three-way catalyst (catalytic converter).

By the way, in the engine E, the ignition timing control, the fuel injection control, and the idle speed control are performed by electronic control using a microcomputer. Here, the ignition timing control according to the present device will be described. A conventionally known method is adopted for the fuel injection control and the idle speed control.

First, as shown in FIGS. 1 (a) and 1 (b), the present ignition timing control device includes a knock sensor 8, a band pass filter 9A, a low pass filter 9B, an A / D converter 10, a microprocessor.
(CPU) 11, which further includes an air flow sensor 12 for detecting the intake air amount, a crank angle sensor 13 for detecting the crank angle, a rotation speed sensor 14 for detecting the engine speed, and another sensor 15 (as the sensor 15, Water temperature sensor,
There is an atmospheric pressure sensor etc.).

Further, a switching transistor (power transistor) 16, a distributor 18, and a spark plug 19 for controlling the connection / disconnection of the ignition coil 17 are also provided as in the conventional case.

Here, the knock sensor 8 detects a knock of the engine E, and its output waveform is as shown in FIG. 5 (a), for example.

The bandpass filter 9A passes a waveform around the resonance frequency of the knock, and the lowpass filter 9B outputs the knock detection signal as an analog signal. The output waveform of the lowpass filter 9B is, for example, It becomes like Fig. 5 (b).

The A / D converter 10 converts the analog signal from the low-pass filter 9B and other analog detection signals into a digital signal, and this digital signal is input to the CPU 11 via the bus line.

By the way, the CPU 11 has the following functions. That is, as shown in FIG. 1 (a), this CPU 11 determines a reference ignition timing (normal ignition advance) SAR according to the operating state of the engine E (state of engine load or engine speed). The determination means 20 is further provided, and further, a knock discrimination means 21 for discriminating the occurrence of knock from the output of the knock sensor 8, and a new first retard control amount for each required time based on the output from the knock discrimination means 21. (First retard amount) First retard control amount determining means for determining RTD1
(First retard amount determining means) 22, second retard angle for determining a new second retard angle control amount (second retard amount) RTD2 at a time interval longer than the required time based on outputs from the knock determining means 21. Control amount determining means (second retard amount determining means) 23,
In addition, an ignition timing calculation means 24 for determining a desired ignition timing SA from the reference ignition timing SAR, the first retard amount RTD1 and the second retard amount RTD2 is provided.

Next, the control procedure using this apparatus will be described with reference to the flowcharts of FIGS. First, basically, the intake air amount and the engine speed are read by the main routine shown in FIG. 2 (step a1), and the regular ignition advance (reference ignition timing) according to the engine operating state is calculated. , This is referred to as SAR (step a2). The reference ignition timing S
The AR is obtained as follows, for example. Ie CP
Since a plurality of ignition timing maps stored for each engine operating state are prepared in U11 and the reference ignition timing SAR is obtained by performing an appropriate interpolation calculation directly from these maps or on the data from these maps. is there. The reference ignition timing SAR is determined by the reference ignition timing determining means 20.

Furthermore, the first retard amount T for knock control
A method for obtaining the ignition timing SA from the RD1, the second retard amount RTD2 and the reference ignition timing SAR will be described with reference to FIG. Now, assume that the knock determination means 21 determines that the engine E is knocked in response to the signal from the knock sensor 8. It should be noted that this determination is made by determining a knock if the detection value based on the knock sensor 8 exceeds a certain reference value (threshold).

When it is determined that the knocking occurs, the knocking voltage is read and VKNO is read in step c1 as shown in FIG.
CK, and then, in step c2, VKNOCK is multiplied by the correction coefficient K to obtain the current retard amount RTDNEW, and in step c3, the current retard amount RTDNEW is added to the first retard amount RTD1 until now, and a new retard amount RTDNEW is added. The first retard amount RTD1 is set.

Then, in step c4, the updated first retard amount RTD
Judge whether 1 is above the upper limit (10 °). If NO
Then, in step c7, the timer C with a retard amount of 10 or more
Reset the RTD. If YES, the first retard amount RTD1 is set to 10 in step c5, and then the timer CAD in which the retard amount is smaller than 10 is set in step c6.
Reset V. The processing up to this point is mainly performed by the first retard amount determination means 22.

After that, in step c8, it is determined whether or not the value of the timer CRTD is larger than the value TIMRTD corresponding to the reference time for increasing the second retard amount RTD2. That is, in step c8, it is determined whether or not the first retard amount RTD1 exceeds the upper limit value (clipped time) for a certain period of time. If it continues, the second retard amount RTD2 is incremented by 1, and this is newly set as RTD2 (step c9), and the timer CRTD is set.
Is reset (step c10).

After that, the process proceeds to step c11, but if NO in step c8, steps c9 and c10 jump, that is, the second
The process of step c11 is performed without increasing the retard amount RTD2.

In this step c11, it is judged whether or not the value of the timer CADV is larger than the value TIMADV corresponding to the reference time for reducing the second retard amount RTD2. That is, in this step c11, it is judged whether or not the retard amount does not exceed the upper limit value (non-clipped time) for a certain period of time.

If it is continued, the second retard amount RTD2 is decremented by 1 to newly set it as RTD2 (step c12), and the timer CADV is reset (step c13).

After that, the process proceeds to step c14. If NO at step c11, steps c12 and c13 jump, that is, the second retard amount RTD2 is not decreased, and the process at step c14 is performed.

At step c14, it is judged if the second retard amount RTD2 exceeds the upper limit value (10).

If it does not exceed, it is determined in step c15 whether the second retard amount RTD2 is smaller than zero.
If YES in step c15, the second retard amount RTD2 is set to 0 in step c16.

In step c14, the second retard amount RTD2 is 10
If it exceeds, in step c17, the second retard amount R
TD2 is set to 10 (upper limit value). The processing up to this point is mainly performed by the second retard amount determining means 23.

Then, in the case of NO in step c15 and in steps c16 and c
After the processing of 17, the processing of step c18 is performed. That is, in step c18, the reference ignition timing SAR,
From the first retard amount RTD1 and the second retard amount RTD2, the calculation of SAR-RTD1-RTD2 is performed to obtain the ignition timing SA. After that, the calculated ignition timing SA
The desired ignition advance value is set based on
9). The processing up to this point is mainly performed by the ignition timing calculation means 24.

The increase and decrease of the first retard amount RTD1 is as follows:
As shown in FIG. 5 (d), in FIG. 5 (d), the portion where the flat state continues for a long time is the clipped portion.

Further, the counting states of the timers CRTD and CADV are schematically shown in FIGS. 5 (e) and (f), and FIG. 5 (g) shows how the second retard amount RTD2 is increased / decreased. become that way.

Further, various counters are used for the above knock control. As a control routine for this counter, the timer routine shown in steps b1 to b8 in FIG. 3 is executed by a timer interrupt signal every 25 msec. There is. In FIG. 3, reference numeral TIM is a timer for reducing the first retard amount. Then, the state of the operation of the timer, which is activated by being interrupted every 25 msec, is schematically shown in FIG. 5 (c).

In this way, when the detection value of the knock sensor 8 exceeds a certain threshold, the retard amount proportional to the exceeded amount is added to the previous retard amount, and if the detection value of the knock sensor 8 is less than or equal to the threshold value. If it is, the first retard amount is decreased with a constant gradient, and if the first retard amount exceeds the upper limit value (10 °), this is clipped at this upper limit value, which is the conventional responsiveness. In addition to the fast knock control system, if the first retard amount is clipped at the upper limit value for a certain period of time, the second retard amount is increased by a certain value (for example, 1), and conversely the first retard amount is clipped to the upper limit value. Since the knock control system with slow response, which reduces the second retard amount by a certain value (for example, 1) if it is not operated for a certain period of time, the water of the water-cooled intercooler 3 drains. Even at the time of abnormal situation, such as say, along with the knocking can be prevented from occurring,
Abnormal retardation that may occur when knock sensor 8 picks up noise is also prevented.

〔The invention's effect〕

As described above in detail, according to the ignition timing control device for the internal combustion engine of the present invention, the knocking is appropriately suppressed by the first retardation control amount while the first retardation control amount is set to the predetermined upper limit value in the normal state. Due to the limitation, it is possible to prevent abnormal retardation due to transient noise, etc., and when an abnormal situation occurs,
By setting the retard angle control amount by the first retard angle control amount and the second retard angle control amount, there is an advantage that knocking at the time of abnormality can be avoided.

[Brief description of drawings]

FIG. 1 shows an ignition timing control device for an internal combustion engine as one embodiment of the present invention, and FIG. 1 (a) is a block diagram of its main part,
FIG. 1 (b) is a block diagram showing the overall configuration, and FIG. 1 (c).
Is an overall configuration diagram of an engine having this device, FIGS. 2 to 4 are flowcharts for explaining the operation thereof, and FIG. 5 is a timing chart for explaining the operation. 1 ... Turbocharger, 2 ... Intake passage, 3 ... Water-cooled intercooler, 4 ... Electromagnetic fuel injection valve, 5 ... Throttle valve, 6 ... Air cleaner, 7 ... Catalytic converter, 8 ... Knock sensor , 9A ... band pass filter, 9B ... low pass filter, 10 ... A / D converter, 11 ... CPU, 12 ... air flow sensor, 13
...... Crank angle sensor, 14 ...... Rotation speed sensor, 15 ...
... Other sensors, 16 ... Switching transistor, 17 ... Ignition coil, 18 ... Distributor, 19 ... Spark plug, 20 ... Standard ignition timing determination means, 21 ... Knock determination means, 22 ... First retard Amount determining means (first retard control amount determining means), 23 ...
Second retard amount determining means (second retard control amount determining means), 2
4 ... Ignition timing calculation means, E ... Engine (internal combustion engine).

Claims (1)

[Claims] 1. A knock sensor for detecting a knock of the internal combustion engine, comprising: a reference ignition timing determining means for determining a reference ignition timing according to an operating state of the internal combustion engine; Knock determination means for determining, first delay angle control amount determination means for determining a new first retard angle control amount based on the output from the knock determination means, and the first delay angle control amount to a predetermined upper limit value. A first retard angle control means for limiting and a second retard angle for determining a new second retard angle control amount when the state in which the first retard angle control amount is limited to the upper limit value continues for a predetermined period or longer. The internal combustion engine is characterized in that a control amount determining means and an ignition timing calculating means for determining a desired ignition timing from the reference ignition timing, the first retard control amount and the second retard control amount are provided. Ignition timing control device.