JPS61152963A - Knocking avoider for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent knocking from occurring as well as to improve drivability ever so high, by installing an ignition timing compensation device, which outputs an ignition timing compensation signal, corresponding to data from a knocking detecting device or a knocking occurrence state memory device, to an ignition timing controlling device. CONSTITUTION:An ignition timing compensation device E for low and medium speed use outputs an ignition timing compensation signal, corresponding direct to a detection signal out of a knocking detecting device B, to an ignition timing controlling device D. A knocking occurrence state memory device F stores a knocking occurrence state in memory. An ignition timing compensation device G for high speed use outputs an ignition compensation signal, found by estimating a knocking occurrence state at an engine high speed range on the basis of data from the memory device F, to the ignition timing controlling device D. This, with the ignition timing compensation, drivability is improvable as surely as possible while preventing the knocking from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a device for controlling the ignition timing of an internal combustion engine to avoid knocking.

(Prior art) When knocking of an internal combustion engine exceeds a predetermined level, it not only reduces the output but also causes impact that adversely affects the pulp and piston. Therefore, by detecting knocking and correcting the ignition timing, it is possible to There is a device designed to avoid knocking (Japanese Patent Application Laid-Open No. 58-1050)
(See No. 36, etc.)

Conventional general knocking avoidance control is performed, for example, as shown in the flowchart of FIG.

That is, when knocking exceeding a reference level is detected by a signal from a knock sensor attached to the cylinder block wall of the engine, etc., the ignition timing is retarded by the maximum amount α. The combustion pressure is lowered by retarding the combustion pressure by a predetermined angle α within a range not exceeding (Sl
-33).

On the other hand, if the state in which knocking is avoided continues for a predetermined period of time, the advance angle is controlled by a predetermined angle β within a range that does not exceed a preset standard advance value (set to a large value to ensure high output). (34-S6).

In this way, while avoiding knocking, the ignition timing is advanced to near the boundary where knocking occurs, thereby ensuring good output and fuel efficiency.

<Problems to be solved by the invention> However, since mechanical noise increases in the high-speed range of the engine, the knocking level/mechanical noise level (S/N ratio) becomes small, and the knocking avoidance control described above is not performed. In some cases, the retard angle control is performed more than necessary, resulting in a problem that good engine performance cannot be maintained.

The present invention was developed in view of these conventional problems, and solves the above problems by correcting the ignition timing in the high speed range based on the knocking occurrence state learned in the low and medium speed range of the engine. An object of the present invention is to provide a knocking avoidance device for an internal combustion engine.

Means for Solving the Problems> Therefore, as shown in FIG. low/medium speed ignition timing correction means E for outputting an ignition timing correction signal directly corresponding to the signal to ignition timing control means for controlling the ignition timing of the ignition device C;
A knocking occurrence state storage means F stores the knocking occurrence state in the low and medium speed range of the engine while updating it with new data, and predicts the knocking occurrence state in the engine high speed range based on the data from the knocking occurrence state storage means F. The configuration includes a high-speed ignition timing correction means G for outputting the ignition timing correction signal obtained by the above process to the ignition timing control means.

With this configuration, in the high speed range where the S/N ratio is small and knocking is difficult to detect, the knocking state learned in the low and medium speed ranges can be used to predict the knocking state in the high speed range. Since the ignition timing is corrected based on the predicted value, good control is performed to avoid knocking while ensuring output, fuel efficiency, etc. even at high speeds.

(Example> The present invention will be explained in detail below.

FIG. 2 shows the configuration of one embodiment, in which a crank angle sensor 2 as an engine rotation speed detecting means is mounted near the crankshaft of the internal combustion engine 1, and a piezoelectric element or the like is mounted on the cylinder block wall. A knock sensor 3 is installed as knocking detection means. Further, an ignition plug 4 is attached to the combustion chamber, and a power transistor outputs an ignition signal to the ignition plug 4.

Together with an ignition circuit 5 consisting of an ignition coil and the like, it constitutes an ignition device.

Signals from the crank angle sensor 2 and knock sensor 3 are input to a control unit 6 containing a microcomputer.

The control unit 6 is provided with the functions of the above-described low/medium speed ignition timing correction means, knocking occurrence state storage means, high speed ignition timing correction means 9 and ignition timing control means using software.

Hereinafter, specific operations will be explained according to the flowchart shown in FIG.

In Sll, the engine speed N and load (fuel injection amount 'rp, etc.) are read, and in S12, it is determined whether the engine speed is in the low/medium speed range below a predetermined rotation speed and in the high load range above a predetermined speed where knocking is likely to occur. Determine whether or not.

Then, in S13, until a predetermined time T has elapsed in the state of the low/medium speed high load region (this may be a cumulative total of intermittent states), the Determine whether or not knocking has occurred, and if knocking occurs,
After incrementing the knocking counter in S15,
In S16, the ignition timing is advanced or retarded in direct response to the knocking signal, as shown in FIG.

In addition, after the predetermined time To has elapsed in a high load state in the low/medium speed range,
In S17, the count values N, C, of the knocking counter are stored and updated in the RAM and then reset.

That is, 316 corresponds to the function as low/medium speed ignition timing correction means and ignition timing control means, and S13 to S15 and S17 correspond to the function as knocking occurrence state storage means.

Then, in step 318, it is determined whether or not the rotation speed is in a high speed range exceeding the predetermined rotation speed, and if it is a high speed range, the process proceeds to S19, and the knocking count value N stored in the RAM is
The latest data of C is read, and in S20, the advance/retard correction amount of the ignition timing, which is set in advance according to the engine speed and load, is stored in the ROM using the count values N and C as parameters. Search from the created 4D map. Here, the amount of correction of the ignition timing is set by predicting the knocking occurrence state in the high speed range based on the knocking occurrence state in the low and medium speed ranges.

In S21, ignition timing correction control corresponding to the data retrieved in S20 is performed.

That is, 318 to 321 correspond to the functions of high-speed ignition timing correction means and ignition timing control means.

In this way, even in high-speed ranges where it is difficult to determine knocking, the ignition timing can be corrected based on the learning results in low- and medium-speed ranges, thereby improving driving performance in high-speed ranges while avoiding knocking. In particular, output, fuel efficiency, etc. can be improved as much as possible.

In addition, the operating conditions for detecting the occurrence of knocking in the low and medium speed range are divided into multiple groups, the occurrence of knocking is detected for each operating condition, and correspondingly, multiple maps in the high speed range are created depending on the operating conditions. If the configuration is such that the correction values are searched for separately, more accurate control can be achieved.

<Effects of the Invention> As explained above, according to the present invention, even at high speeds, drivability can be improved as much as possible while avoiding knocking by correcting the ignition timing based on learning in the low and medium speed ranges. effective.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration and functions of the present invention, FIG. 2 is a schematic configuration diagram of an embodiment of the present invention, FIG. 3 is a flowchart of knock avoidance control of the same embodiment, and FIG. 4 is a conventional It is a flowchart of an example of knock avoidance control. 1... Internal combustion engine 2... Crank angle sensor 3...
・Knock sensor 4...Ignition plug 5...Ignition circuit 6...Control unit Patent applicant Japan Electronics Co., Ltd. Representative Patent attorney Fujio SasashimaFigure 3

Claims (1)

[Claims] In a knock avoidance device for an internal combustion engine that detects knocking that occurs in the internal combustion engine and corrects ignition timing to avoid knocking, knocking is detected in the low and medium speed range of the engine as detected by the engine speed detection means. low/medium speed ignition timing correction means for outputting an ignition timing correction signal directly corresponding to the detection signal from the detection means to the ignition timing control means;
A knocking occurrence state storage means stores the knocking occurrence state in the low and medium speed range of the engine while updating it with new data, and predicts the knocking occurrence state in the engine high speed range based on the data from the knocking occurrence state storage means. 1. A knocking avoidance device for an internal combustion engine, comprising: high-speed ignition timing correction means for outputting the determined ignition timing correction signal to ignition timing control means.