JPH0385374A - Ignition timing controller of internal combustion engine - Google Patents

Abstract

PURPOSE:To normally and accurately perform judgement of knocking and improve ignition timing control by making differ priority constants at transient and normal times under the operation condition of an internal combustion engine, and averaging them after adding so as to calculate a knocking comparison value. CONSTITUTION:The operation condition of an internal combustion engine is detected by a means A, and knocking of the engine is detected by a means B. Priority coefficients are set different at normal and transient times by a means C based on the detection operation condition. A new comparison value is set by a means D by addition-averaging the detection value of knocking and the former comparison value based on the set priority coefficients. Knocking is judged by a means E based on the new comparison and detection value of knocking. Thereafter ignition timing is set by a means F based on the judgement of the knocking, and an ignition plug G is controlled by a means H so as to actuate it in response to the set ignition timing.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an ignition timing control device for an internal combustion engine, and particularly to a technique for suppressing knocking.

<Prior Art> Conventional examples of this type of ignition timing control device include the following.

That is, engine operating conditions (e.g. engine speed and engine load)
The ignition timing ADV is set according to the ignition timing ADV, and the ignition plug is operated to ignite at the set ignition timing ADV. Further, when knocking occurs, the ignition timing ADV is retarded by a predetermined amount (for example, 1°) to suppress the occurrence of knocking. Further, when knocking does not occur, the ignition timing is advanced as much as possible near the knocking non-occurrence limit region to increase engine output.

Here, the determination of whether or not knocking has occurred is performed as follows. That is, when knocking does not occur, the output value of the knocking sensor is integrated at every predetermined crank angle, and this integral value KSI.

and the previous integral value KSI. Alternatively, a new background level GL is obtained by weighted averaging the previously obtained background level BGL using a predetermined weighting coefficient.

Then, the value obtained by adding the knock judgment value SL to the obtained BGL (BGLN + SL) is compared with the output value of the knocking sensor, and it is determined that knocking has occurred when the output value > BGL + SL. ing.

<Problems to be Solved by the Invention> However, in such conventional ignition timing control devices, a new GL is determined by always weighting the BGL using a constant weighting coefficient, so the following problem is solved. There is a problem. .

That is, during steady operation, BGL changes so as to substantially correspond to the output of the knocking sensor as shown in FIG. 4, so that knocking can be accurately determined. However, during acceleration operation, the BGL is unable to follow changes in operating conditions as shown in Figure 5, and it is determined that knocking has occurred even though knocking has not occurred, causing the ignition timing to be retarded and engine output to decrease. There is a problem with this.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ignition timing control device that can satisfactorily determine the occurrence of knocking under all operating conditions.

<Problems to be Solved by the Invention> For this reason, the present invention, as shown in FIG. a weighting coefficient setting means C that sets different weighting coefficients depending on whether the operating state is steady operation or transient operation; and a detection value of the knocking detection means B based on the set weighting coefficient. knock comparison value setting means for setting a new knock comparison value by weighted averaging of a value corresponding to the previous knock comparison value and a previously set knock comparison value; knocking determination means E for determining whether or not knocking has occurred based on the determination result; ignition timing setting means F for correcting and setting the ignition timing to suppress knocking based on the determination result; An ignition control means H for igniting the ignition plug G is provided.

In this way, during steady operation, the previous knock comparison value is given a larger weight to prevent knocking from being erroneously determined even if noise or the like mixes into the detected value of the knock detection means, while during transient operation At times, greater weighting is given to the detection value of the knocking detection means than during steady operation, so that the knock comparison value can follow changes in the operating state with good responsiveness.

<Example> An example of the present invention will be described below with reference to FIGS. 2 and 3.

In FIG. 2, a control device l consisting of a microcomputer etc. receives a reference signal (corresponding to the engine rotational speed) and a positive signal from a crank angle sensor 2.
The intake air flow rate detection signal from the air flow meter 3, the knocking detection signal from the knocking sensor 4 as a knocking detection means, the water temperature detection signal from the water temperature sensor 5, and the throttle valve opening detection signal from the throttle sensor 6 are transmitted. , is human-powered.

The control device 1 operates according to the flowchart shown in FIG. 3, outputs an ignition signal to the ignition plug 8 at a set ignition timing via an ignition device 7 consisting of an ignition coil, a power transistor, etc., and performs an ignition operation. It has become.

Here, the control device 1 constitutes a weighting coefficient setting means, a knock comparison value setting means, a knocking determination means, and an ignition timing setting means. Further, the control device 1 and the ignition device 7 constitute an ignition control means, and the crank angle sensor 2 and the air flow meter 3 constitute an engine operating state detection means.

Next, the operation will be explained according to the flowchart shown in FIG.

First, to explain normal ignition timing control, for example, the ignition timing ADV is determined based on the engine rotation speed and the engine load such as the basic injection amount.
is set, and an ignition signal is output to the ignition plug 8 via the ignition device 7 at the set ignition timing ADV to activate the ignition.

During such ignition timing control, a routine shown in the flowchart of FIG. 3 is executed.

At Sl, detection signals from the crank angle sensor 2, air flow meter 3, etc. are read.

In S2, the current engine operating state is knocking control 'a?
iJ [area (for example, medium-speed/high-speed load operation area) or not is determined. If YES, proceed to S3; if NO, terminate the routine.

In S3, it is determined whether or not the opening change rate Δα of the throttle valve detected by the throttle sensor 6 is zero. If YES, that is, in steady operation, the process proceeds to S4; if NO, that is, in transient operation, the process proceeds to S1.

In S4, the weighting coefficient Xl (for example, 1
6) Search from the map.

In S5, a new knock comparison is made from the retrieved weighting coefficient XI, the integral value KSI obtained by integrating the output value of the knock sensor 4 at each predetermined crank angle, and the background level BGL obtained in the previous routine. The background level BGL as a value is calculated using the following equation.

BGL, = 256XKS I/XI +BGL0X(
XI-1)/X.

On the other hand, in Sl, the weighting coefficient X (for example, 8) during transient operation is searched from the map.

In S7, a new background level B is determined from the detected weighting weighting coefficient X2, the integral value KSI, and the background level BGL in the previous routine.
GL is calculated using the following equation.

BGLN -256XKS I/Xg +BGLO(x
zl ) / becomes more weighted.

In S8, the knock judgment value SL is set to the background level BGLH calculated in S5 or S7.

It is determined whether the added value is greater than or equal to the output value of the knocking sensor 4. If YES, the process advances to S9, and if NO, the process advances to 310.

In S9, it is determined that knocking is not occurring and the 31
Go to 1.

In 510, it is determined that knocking has occurred, and the process proceeds to S11.

Sll performs knocking control, that is, when knocking occurs, the ignition timing ADV set in the normal ignition timing control is retarded by, for example, 1° in order to suppress knocking. On the other hand, when knocking does not occur, the ignition timing ADV is advanced as much as possible near the knocking non-occurrence limit.

At the ignition timing obtained in this way, an ignition signal is output to the ignition plug 8 via the ignition device 7 to activate the ignition.

As explained above, during transient operation, the weight given to the integral value KS■ is increased and the previous background level BGL is
, and the integral value KSI to obtain the new background level BGLN, the new background level BGL can be changed to follow changes during transient operation with good responsiveness. Therefore, even during transient operation, the occurrence of knocking can be accurately determined, and excessive retardation can be prevented, thereby preventing an excessive decrease in output. Also, during steady operation, the previous background level B
Since the weighting of GL is increased, even if noise or the like is mixed into the output of the knocking sensor 4, knocking can be detected with high accuracy without being erroneously determined.

<Effects of the Invention> As explained above, the present invention calculates the knock comparison value by setting different weighting coefficients for excessive operation and steady operation and performing a weighted average. It is also possible to accurately determine knocking, prevent an excessive drop in output, and prevent erroneous determination of knocking due to noise, etc., even during steady operation.

[Brief explanation of drawings]

Fig. 1 is a claim correspondence diagram of the present invention, Fig. 2 is a configuration diagram showing an embodiment of the present invention, Fig. 3 is a flowchart of the same as above,
FIG. 4 and FIG. 5 are diagrams for explaining the conventional drawbacks. 1...Control device 2...Crank angle sensor 3
... Air flow meter 4 ... Knocking sensor 6 ... Throttle sensor 7 ... Ignition device 8
...Spark plug

Claims (1)

[Claims] An engine operating state detection means for detecting the operating state of the engine, a knocking detection means for detecting engine knocking, and a weight that sets different weighting coefficients depending on whether the detected operating state is steady operation or transient operation. a knocking coefficient setting means, and a knocking unit for setting a new knock comparison value by weighted averaging of the detection value of the knocking detection means or a value corresponding thereto and the previously set knock comparison value based on the set weighting coefficient. a comparison value setting means; a knocking determination means for determining whether or not knocking has occurred based on the set knock comparison value and a detection value of the knocking detection means; 1. An ignition timing control device for an internal combustion engine, comprising: an ignition timing setting means for correcting and setting an ignition timing; and an ignition control means for igniting an ignition plug based on the set ignition timing.