JPS60100021A - Knocking controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To enable the detection of abnormality in a knocking sensor with a simple construction by detecting disconnection, detachment or the like of the knocking sensor with a resistance bridge containing a resistance provided in parallel with the knocking sensor. CONSTITUTION:A resistance R2 is connected in parallel to a knocking sensor 2. A voltage R4V/(R3+R4) determined by resistance values of resistances R3 and R4 is inputted into a terminal S2 of a comparator C1 and when the knocking sensor 2 operates normally, a voltage R2V/(R1+R2) determined by the resistances R1 and R2 is inputted into a terminal S1. When the knocking sensor suffers a disconnection or a poor connection for some reason or other, the drop in the voltage due to the R2 is gone. In this case, the voltage V is inputted directly into the terminal S1. Therefore, when resistance values R1-R4 are set so that a voltage R4V/(R3+R4) exists between the voltage R2V/(R1+R2) at the normal time and the voltage V at the abnormal time, it is possible to compare inputs S1 and S2 of the comparator C1 for detecting abnormality of the sensor 2.

Description

Detailed Description of the Invention (1) [Field of Industrial Application] The present invention detects knocking by vibrations or sounds generated inside and outside the cylinder due to internal cylinder pressure of an internal combustion engine, and when non-king is detected, the ignition timing is adjusted. This invention relates to an ignition timing control device for an internal combustion engine that has the function of retarding the ignition timing of an internal combustion engine.

[Prior art]

In recent years, various so-called knock control systems (abbreviated as Iu KC3) have been studied, which detect non-king occurring in internal combustion engines and advance or retard ignition timing. By the way, if the knock sensor used for knock determination malfunctions for some reason and is no longer able to send a normal signal to the knock controller, there is a risk of major damage to the internal combustion engine. In conventional methods, in order to avoid this danger, abnormalities are detected by performing amplification processing, integration processing, etc. on the minute output signal of the knock sensor separately from the knock judgment circuit, and comparing it with a predetermined value (for example, Kaisho 56-7
Publication No. 7555). For this reason, the circuit scale of the knock controller has become large and complex, making the system (2) more expensive.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the problems of the prior art, it is an object of the present invention to detect wire disconnections and sensor wire breaks, which account for most of the abnormalities in knock sensor signals, with a resistor circuit having a simple configuration.

〔Example〕

The present invention will be explained below with reference to embodiments shown in the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. 1 is the internal combustion engine body, 2 is a knock sensor such as piezoelectric type or coil type, 3
is a knock controller that outputs an ignition timing control signal according to the output from the knock sensor. The functional configuration of the knock controller includes an abnormality detection unit (31) that determines whether the knock sensor is normal or abnormal, and a filter (32) such as a bandpass or bypass filter that selects and extracts only the knock frequency component.
), a knock determination level creation unit (34) that creates a reference threshold for knock determination, a knock determination unit (35) that compares the knock determination level and the knock sensor signal, and an ignition unit that compares the knock determination level and the knock sensor signal, and ignition based on the knock determination result and the abnormality determination result. It is composed of an ignition timing control signal output section (36) that outputs a timing control signal (3). Note that when the knock sensor is abnormal, the ignition timing is set to be retarded by a predetermined amount, for example. (4) is an ignition signal generating device that generates ignition sparks in response to a control signal from the knock controller (3).

FIG. 2 shows details of the knock sensor abnormality detection section (31). The numbers in the figure are the same as in FIG. The knock sensor abnormality detection section (31) is shown in detail in an enlarged manner. The resistor R2 in the figure may have a built-in knock sensor or an external type. A voltage (R4/ (R3+Ra>) determined by the resistance values of resistors R3 and R4 is applied to the terminal S2 of the comparator C1.
(2) is applied manually, and when the knock sensor 2 is normal, a voltage (R2/
(R1+R2)) V is input. Next, if the knock sensor becomes disconnected or poorly connected for some reason, R2
In this case, terminals S,
A voltage V is input directly to the terminal. Therefore, the normal voltage (R2/
(R area + R2)) Voltage (R) between V and abnormal voltage (V)
4/R3+R4) ・If the resistance value RI+ R2, R3, and R4 are set so that (4) exists, an abnormality in the knock sensor 2 can be detected by comparing the input S + + S2 of the comparator C1. Can be done.

〔Effect of the invention〕

As described above, the present invention detects disconnection or disconnection of the knock sensor using a resistor bridge including a resistor provided in parallel with the knock sensor, so that abnormalities in the knock sensor can be detected with a simple configuration. be able to.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of an embodiment of the present invention, and FIG. 2 is a detailed circuit diagram of the knock sensor abnormality detection circuit in FIG. 11. DESCRIPTION OF SYMBOLS 1... Engine, 2... Knock sensor, 3... Knock controller, 31... Abnormality detection circuit, Rl
+ R2+R3+ R4...Resistor, C1...Comparator. Representative Patent Attorney Takashi Okabe (5)

Claims (1)

[Claims] 11) A knock sensor that detects knocking occurring in an internal combustion engine, and a knock that makes a knock determination based on the output from the knock sensor, detects an abnormality in the knock sensor, and outputs a knock control signal. In a knocking control device for an internal combustion engine, which includes a controller and an ignition signal generating device that generates an ignition signal based on the control signal, abnormality detection of the knock sensor includes a resistance bridge including a resistance provided in parallel with the knock sensor; 1. A knocking control device for an internal combustion engine, comprising a comparator that detects an abnormality in a knock sensor by comparing voltages across a resistance bridge. (21) The non-king control device for an internal combustion engine according to claim 1, characterized in that a resistor provided in parallel with the knock sensor is built into the knock sensor.