JPS61258966A - Knocking control device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To control the ignition timing of an engine by discriminating to be in a knocking condition if the crank angle has not reached a given value at the arrival time of flame face, judging from the informations from a crank angle sensor and a flame face sensor. CONSTITUTION:While a d.c. high voltage is impressed between electrodes 61a and 61b of a flame face sensor 6, if the front face of flame generated by an ignition plug 5 reaches a flame sensor 6, current begins to flow and this current is input into a detecting circuit 73. And this is input into an analysis circuit 75. Since the information of crank position is transmitted to the analysis circuit 75 by a crank angle sensor 3 via a control circuit 74, whether or not the crank angle has reached a given value at the arrival time of flame face is checked. And if it has not reached a given value, it is discriminated that an engine 2 is in a knocking condition and the ignition timing is delayed by a prescribed crank angle. On the contrary, if it is not in a knocking condition, the ignition timing is advanced by a prescribed crack angle in a prescribed time. Thus, the combustion efficiency of the engine can be enhanced to the maximum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a knocking control device for an internal combustion engine in which a spark plug and a flame front sensor are attached to one cylinder.

[Prior Art] As a means of automatically detecting the occurrence of a knocking condition in an internal combustion engine and stopping or taking preventive measures, a vibration detection type knock sensor that detects the vibration of the engine cylinder wall due to the occurrence of a knocking condition has conventionally been used. The method used was to control combustion based on information from However, in the vibration detection type knock sensor, the accuracy of detecting a knocking state is considerably reduced when the engine rotation speed is high (3 oorpm or higher) due to mechanical noise of the engine. Another method used is to perform combustion control based on information from a pressure-sensing knock sensor that detects fluctuations in engine cylinder internal pressure due to the occurrence of knocking, but pressure-sensing sensors are subject to vibrations. There is a drawback that the sensitivity may be drastically reduced or become unstable, and while maintaining the required detection accuracy,
Moreover, it has been difficult to manufacture a pressure sensing type sensor that is small enough to be installed inside the cylinder without causing any problems.

On the other hand, a measuring instrument called a flame front sensor has been introduced as a new means for understanding the combustion status of the air-fuel mixture in the combustion chamber of an internal combustion engine. Recent SAE reports (
American Society of Automotive Engineers Report) N 0.840441
A technical report has been made stating that this flame surface sensor can be used as a means for detecting a knocking condition in an engine cylinder.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 57-99271, a flame front feeler (sensor) is provided at a position away from the spark plug in the cylinder to measure the time it takes for the flame generated by ignition to reach. One possible method is to detect the knocking state using an electronic circuit and control the ignition timing.

[Problems to be Solved by the Invention] However, the conventional flame surface feeler (sensor) as disclosed in Japanese Patent Application Laid-open No. 57-99271 has been found to be more effective at preventing fires caused by automatic ignition when the flame is ignited than by fires ignited by plugs. It needed to be installed in a position where it could be detected first. Therefore, the mounting position is highly restricted and is not practical.

SUMMARY OF THE INVENTION An object of the present invention is to provide a knocking control device for an internal combustion engine that controls the ignition timing of an internal combustion engine using a flame front sensor that detects the timing of arrival of a flame front in order to determine the knocking state of an internal combustion engine.

[Means for solving the problems] The first invention of the internal combustion engine knocking control @ device of the present invention is as follows:
In an internal combustion engine with a spark plug installed in the combustion chamber, there is a crank angle sensor that detects the rotation angle of the crankshaft of the engine, and a crank angle sensor that is installed in the combustion chamber and determines when the flame front reaches the spark plug. Based on the information from the flame surface sensor that detects the crank angle sensor and the flame surface sensor, it is determined that the iWA is in a knocking state when the flame surface arrival timing has not reached a certain crank angle. The configuration includes a control circuit that controls the II function based on the information.

[Actions and Effects of the Invention] The knocking control device for an internal combustion engine according to the present invention having the above configuration has the following actions and effects.

A flame surface sensor measures the flame surface arrival timing, a combustion pressure sensor measures the knocking vibration intensity, and as shown in Figure 2, when the two are correlated, the knocking state (al, a
2, a3, a4, a5) occurs, the flame surface reaches earlier (bi, b2, bs, b4, bs)
is detected, and it can be said that there is a correlation between the timing at which the flame surface is reached by the flame surface sensor and the knocking vibration intensity measured by the combustion pressure sensor. By measuring, knocking condition can be detected.

(Example) If a flame is detected by the flame front sensor before a certain crank angle, it can be determined that a knocking condition has occurred.

c) Since the ignition timing of the internal combustion engine can be set at the point at which the maximum rotational output is obtained as long as knocking does not occur, the combustion efficiency of the internal combustion engine, that is, the rotational torque generated per unit fuel consumption can be maximized.

[Embodiment] A knocking control device for an internal combustion engine according to the present invention will be explained based on an embodiment shown in the drawings.

FIG. 1 shows a circuit of an internal combustion engine knock control yII device according to the invention, which includes a cylinder of an automobile engine in which a flame surface sensor and a crank angle sensor are incorporated.

A knocking control device 1 for an internal combustion engine includes a crank angle sensor 3 that detects the rotation angle of a crankshaft 26 of an automobile engine 2 from a crank angle detection rotary disk 31 attached to a crankshaft 26, and an ignition sensor attached to a combustion chamber 4. Plug 5 and
Two insulated electrodes 61a and 61b are protrudingly installed in the combustion chamber 4, and include a flame surface sensor 6 that detects the time it takes for the flame surface to arrive from the ignition plug 5, that is, the timing at which the flame surface arrives, and the crank angle sensor. 3 and a control circuit γ that determines the knocking state of the engine 2 and controls the combustion of the engine 2 when the flame surface arrival timing has not reached a certain crank angle based on information from the flame surface sensor and the like. .

The engine 2 includes a cylinder 23 formed in a cylinder block 22 to which a cylinder head 21 is assembled, a piston 24 that slides inside the cylinder 23 while maintaining airtightness, and forward movement of the screws 24. a crankshaft 26 which is converted into rotational motion via a piston rod 25;
An intake pipe 27 that supplies air-fuel mixture into the cylinder 23, an exhaust pipe 28 that exhausts exhaust gas from the cylinder 23,
The intake pipe 27 is provided with a 1' angle extension valve 29.

The control circuit 7 includes a circuit 72 for applying a DC high voltage to the flame surface sensor 6, and a circuit 72 for applying a DC high voltage to the flame surface sensor 6, and a circuit 72 for applying a DC high voltage to the flame surface sensor 6.
, 6Ib, an analysis circuit 75 that receives input from the control circuit 74 of the crank angle sensor 3 and the detection circuit 73, an ignition signal processing circuit 76 which is a knocking control circuit, and a spark plug 5. and a distributor 78 for distributing high voltage secondary current to.

Next, the operation of the knocking control device for an internal combustion engine according to the present invention will be explained based on FIGS. 1 to 4.

When the DC high voltage generated by the circuit 72 is applied between the electrodes 61a and 61b of the flame surface sensor 6, a current starts flowing when the front of the flame generated at the ignition plug 5 position reaches the flame surface sensor 6. , this current is input to the detection circuit 73. This information is then output to the analysis circuit 75. The analysis circuit 75 receives the crank position information detected by the crank angle sensor 3 and the crank angle sensor control circuit 74.
Since the crank position, or in other words, the crank angle, has reached a certain value when the flame surface is reached, it is checked whether the crank position, or in other words, the crank angle, has reached a certain value. Information is transmitted to the ignition signal processing circuit 76 for correction, and the distributor 18 distributes the discharge current to the spark plug 5 based on the ignition timing determined by this circuit. The correction of the ignition timing of the ignition signal processing circuit 7G is as shown in FIG. 3. The relationship between the flame front arrival timing and the knocking state is as follows: when the flame reaches the flame front sensor 6 from the spark plug 5 earlier than A. In all cases (100%), knocking occurred. Before B, about 1/2 (50
%) knocking condition has occurred. In other words, as a method of controlling the knocking state, when the flame reaches before A, that is, when the flame surface arrival time has not reached a certain crank angle, it is determined that the engine 2 is in the knocking state, and the engine 2 is determined to be in the knocking state and Position) The ignition timing is delayed, and when the arrival of the flame is detected, for example, twice before B, or when the flame arrives before B twice within a predetermined time (predetermined number of times), that is, when the flame front arrival timing is constant. When the crank angle has not been reached, it is determined that the engine 2 is in a knocking state and the combustion of the engine 2 is controlled as shown in the graph shown in FIG. 4 by delaying the crank angle by a predetermined crank angle (shifting a predetermined piston position). Alternatively, when the flame arrives before B, it may be determined that knocking has occurred and the ignition timing may be delayed by a predetermined crank angle.

Conversely, when no knocking condition is detected, the ignition timing is advanced by a predetermined crank angle for a predetermined time.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of the structure of the internal combustion 11rIA knocking control device of the present invention, Fig. 2 is a graph showing the correlation between the flame front arrival timing measured by the flame front sensor and the knocking vibration intensity measured by the combustion pressure sensor, and Fig. 3.4. The figure is a graph showing the relationship between the flame front arrival timing and the knocking state. In the diagram: 1. Knocking control device for internal combustion engine 2..
・Engine 3... Crank angle sensor 4... Combustion chamber (cylinder) 5... Spark plug 6... Flame front sensor 7... Control circuit diagram 2 Flame front arrival timing 12 Burning pressure sensor notching Vibration rage 3rd figure 4th figure

Claims (1)

[Scope of Claims] 1) An internal combustion engine in which a spark plug is attached to a combustion chamber, comprising: a crank angle sensor for detecting a rotation angle of a crankshaft of the engine; Based on information from a flame front sensor that detects the flame front arrival time, the crank angle sensor, and the flame front sensor, when the flame front arrival time does not reach a certain crank angle, the engine knocks. A knocking control device for an internal combustion engine, comprising a control circuit that determines the state of the engine and controls the engine based on the information.