JPS6153459A - Ignition controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To perform continuous rating time control over an ignition coil in time of accelerating in an accurate manner, by charging a condenser in accordance with a rising characteristic in a primary current, while generating an accelerating pulse according to the charging waveform, in case of a device performing the continuous rating time control of the ignition coil. CONSTITUTION:In case of a controlling device 200 which inputs an input signal A commensurate to the continuous rating time found by an operational device (unillustrated here-in) at a previous stage, there is provided with a resistor 2230 or being an impedance element for detecting a primary current for an ignition coil 30, and a primary current waveform of the ignition coil 30 appearing as voltage of this resistor 2230 drops is made to be outputted via an amplifier 2410. In addition there is provided with a time constant device inclusive of a condenser 2470 to be charged so as to simulate a rising characteristic of the said primary current, and a charging voltage waveform of the condenser 2470 is compared with a reference voltage 2480 by a comparator 2490. And, an accelerating pulse is generated according to the charging waveform of the condenser 2470 whereby optimum continuous rating time is made so as to be secured in time of acceleration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ignition control device for an internal combustion engine that controls the energization time of a primary current in an ignition coil.

[Prior art of the present invention]

In the conventional i1N1 time control method of the ignition coil of an electronic advance angle device using a microcomputer, the energization time is stored in advance in the memory of the microcomputer in the form of a calculation means or map as a function of the power supply voltage and engine rotation speed. ,
There was a method to determine the iIN electric time opening time by referring to this as necessary (for example, Japanese Patent Application Laid-Open No. 57-1958).
(See Publication No. 67).

In addition, in an ignition timing generation circuit consisting of a microcomputer, a counter, etc., the signal 1! It
There was one that generated a signal corresponding to a constant rotation angle of the engine, with the edge indicating the ignition timing, and used this signal to create the ignition coil energization time using a separate analog circuit.

First, in the former method, since the energization time is determined in advance, it may not be possible to ensure the optimum energization time in response to manufacturing variations, temperature rises, or rotational speed changes such as during acceleration. In a circuit that has a constant current control function that controls the ignition coil primary current so that it does not exceed a set value, if the time during which the ignition coil primary current reaches this constant current increases slightly, the heat generation of the circuit elements will rapidly increase, resulting in the worst case scenario. In some cases, the element may be damaged.

Next, while the latter method does not have problems such as variations in manufacturing, it requires a complicated circuit for controlling the energization time, and it is not sufficient to secure the optimum energization time during acceleration. FIG. 1 shows a block diagram of an ignition system using this method, and FIG. 2 shows main operating waveforms. The ESA control section 2 calculates the ignition timing from the reference position signal generator 1 according to the engine operating state, and outputs an ignition signal with a width of 30"CA to the igniter 3. The igniter 3 performs closing angle control based on the above ignition signal. The timing to start supplying the primary current to the ignition coil 4 is determined.

In this method of controlling the closing angle of the igniter 3, a ramp wave is generated from the trailing edge of the ignition signal, that is, from the ignition timing, as shown in FIG. When this ramp wave reaches the operating level, electricity is turned on. Here, the slope of this ramp wave is changed, and becomes steeper as the speed increases. In addition, the operating level is high at low speeds and low at high speeds (so that a nearly constant energizing time is always ensured.The time during which the ignition primary current is above a predetermined value (this is called constant current time) is detected and If the constant current time becomes long, the operating level is raised and control is performed so that the optimal closing angle is always obtained.In this way, the ramp waveform is used to enable control over a wide engine speed range from low speed to high speed. This has disadvantages such as a complicated circuit configuration due to changing the inclination and operating level of the engine.Note that 5 is a spark plug, 6 is an ignition switch, and 7 is a battery.

[Object of the present invention]

The present invention has been made in view of the above problems, and in a device that controls the energization time of an ignition coil, in order to correct the energization time particularly during acceleration, a capacitor is adjusted in accordance with the rise characteristics of the primary current of the ignition coil. For internal combustion engines, the optimal energization time can be obtained even during acceleration by charging the ignition coil, obtaining an acceleration pulse according to the acceleration state from this charging waveform and a predetermined reference voltage, and extending the energization time of the ignition coil. The purpose is to provide an ignition control device.

[One embodiment of the present invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ignition control device for an internal combustion engine according to the present invention will be described below with reference to the accompanying drawings.

FIG. 3 is a block diagram showing the configuration of the present invention.

Reference numeral 10 denotes a reference position signal generating means for generating a reference position signal in synchronization with the rotation of the internal combustion engine. Reference numeral 20 indicates various sensors for sensing the operating conditions of the engine.

100 is a calculation means, which calculates a predetermined ignition timing by inputting operating conditions such as engine load and rotation speed from a signal generation means 10 and various sensors 20, and calculates a predetermined ignition timing by a predetermined time before the ignition timing. The ignition coil energization start timing is calculated, and a signal indicating the above-mentioned energization start timing and ignition timing is output based on the signal from the signal generating means 10.

The calculation means 100 includes a CPU 10 and an A/D converter 12.
0, a memory 130, and an input/output device 140 including a human output board and a counter. Reference numeral 200 denotes a control means which inputs the output signal of the calculation means 100 and performs correction by delaying the energization start time of the output signal and shortening the energization time calculated by the calculation means 100 in order to always generate optimal ignition performance. Let's do it. The control means 200 includes a closing angle control unit 210, an ignition coil, and one of the
Constant current control output unit 220 and ignition coil 3 that control the conduction of the secondary current and the primary current so that it does not exceed a set value
It is composed of a primary current detection section 230 that detects a primary current of 0 and generates a signal according to the current. Ignition coil 30
By changing the current in the primary winding, a high voltage is generated in the secondary winding, and an ignition spark is generated at the ignition plug 60. Ignition switch 40 controls energization of battery 50.

FIG. 4 is a chronological explanation of the calculations performed by the calculation means 100, and FIGS.
3 is a flowchart showing the flow of calculation processing in the figure. FIG. 5(a) shows the main routine, and FIG. 5(b) shows the interrupt routine. The main routine performs processing that does not require much synchronization with the rotation of the engine, whereas the interrupt routine is executed in synchronization with the rotation of the engine and is performed as an interrupt process that interrupts the execution of the main routine. In the main routine, first, after starting the program, various initializations are performed, and then the operating state of the engine is input from various sensors 20, and the time T180 required for the rotation of the engine's crankshaft iao' determined by the above interrupt processing is stored in the memory. The advance time TESA stored as a data table in the memory 130 is obtained by interpolating the table and stored in the memory 130. The advance time here is the advance time from TDC to the ignition timing, and is obtained by converting the advance amount (angle) into time. Next, the battery voltage ■3 is inputted by the A/D converter 120 to calculate TVll. An example of TVll is shown in FIG. 6. In this way, TVR is expressed as a function of the power supply voltage ■8, and in actual processing, the TVI table stored in the memory 130 is interpolated from the voltage ■8. to calculate the desired Tvs and store it in the memory 130.
Store in. Next, T, 8. From TVI1, the primary current conduction time T of the ignition coil 30 is determined by the following formula. Calculate N.

TON=(Tlll11/16) +Tv++ Next, the off time T of the primary current of the ignition coil 30. F.

Calculate. TOFF is the power supply voltage ■ as shown in Figure 7.
, is calculated from. Energization time T. , T compared to 4. N
is long and T. If F cannot be secured, T. Reduce 8 and get this! Opening hours T. , f in the memory 130. After this, other processing is performed and this loop is repeated thereafter.

To explain the interrupt routine, processing 1 is performed immediately after the TDC of the reference position signal 1, and first, the time Tl1l10 required for the rotation of the engine crankshaft 180, which is measured using the counter 110140, is stored in the memory 130.
Next, the count time 'tI for energization is calculated from the following equation and output to the counter 140.

j l= T +so Toll T'EsA where T. For N and TEsA, the values calculated in the main routine and stored in the memory 130 are used. Then, after a predetermined energization count, an output signal to start energization is generated, and immediately after this, the interrupt processing routine of process 2 is executed, and the count value T is set in the ignition timing counter. H is loaded, and an ignition timing output signal is generated at the ignition timing calculated thereby.

FIG. 8 shows an electrical circuit diagram of the control means 200, particularly showing the closing angle control section 210 in detail.

The input signal to the control means 200 is set as the ignition timing at the falling edge of the pulse. 2040 is a constant current source that charges the capacitor 2030, and 2010 is an inverter that controls the switch 2020 to discharge the capacitor 2030.

2050 is a constant current source, 2060 is a switch, 2070 is a capacitor, and 2080 is a switch. 2090 is a constant current source, the current value of which is controlled by the power supply voltage 8.

2100 is a switch, 2110 is a constant current source, 2120 is a comparator that compares the potentials of capacitor 2030 and capacitor 2070, 2130 is an AND gate, 2210
230 is a constant current control unit that drives the power transistor 2220 to prevent the primary current of the ignition coil 30 from exceeding a predetermined current value, and 230 is a current that detects the primary current of the ignition coil 30 from the potential of the current detection resistor 2230. This is a detection circuit.

Next, as for the configuration of the part related to acceleration detection for closing angle control, 241O is an amplifier that amplifies the voltage of resistor 2230 and connects it to capacitor 2470 through diode 2420.
A voltage waveform similar to the primary current waveform of the ignition coil 30 is generated. 2440 is an AND game 1-, with an inverter on one side of the two-man force. 2450 is a switch, 246
0 is a constant current source, 2430 is a capacitor, a resistor forms a CR time constant circuit together with 2470, 2480 is a reference voltage for a comparator 2490, and 2500 is a gate that generates an acceleration pulse ACC.

FIG. 9 shows waveforms of each part of the control means 200. The human input signal A is the output of the calculation means 100, and the approximate energization time is determined, and the rising and falling edges are used as the energization and ignition timings, respectively. Switch 2020 receives inverted input signal A
Since it is conductive for a period of , the terminal voltage of the capacitor 2030 is
203 is a ramp wave that rises from the rise of the human input signal A and is reset by the inverted input signal A. capacitor 2
070 is charged by the current 1205 of the constant current source 2050 after a constant current time. On the other hand, the discharge is from the ignition coil 30
The period of the inverted closing angle output B during which the primary current of is not conducting,
This is performed by a current 1209 of a constant current source 2090 and a current 1211 of a constant current source 2110 from which the acceleration pulse is output. The terminal voltage V2O7 of the capacitor 2070 is compared by the comparator 212O, and when the terminal voltage 203 becomes higher than the terminal voltage V2O7, the 1st voltage of the ignition coil 30 is detected.
This is the next energization start time. The output of the comparator 2120 is subjected to a logical operation with the input signal A by the NA'ND circuit 2130, and becomes an inverted closing angle output signal B that controls the energization of the primary coil of the ignition coil 30 and the ignition timing. Coil primary current 1
1 is a current flowing through the primary side of the ignition coil 30, and a constant current pulse T is a signal output from the current detection unit 230 during a period when the primary current 11 exceeds a set value.

Figure 10 (al, (b) shows how the constant current time converges to the set value by the closing angle calculation. This shows how the timing is delayed. Also, Figure 10 (bl) shows how the next 1ffl current start timing is advanced when the previous constant current time is short. In this way, the constant current time is always at the set value. The value of the capacitor 20 is determined by the waveform shown in FIG.
70 is charged with a constant current 1205 during a constant current time T, and discharged with a constant current 1207 during a period T. Therefore, the following formula holds.

1205xTc /c207=i207X (T's.

Tc Tco+t) / C207 Te=i 207 (T+ao TcotL) /
(i205+4207) Here, Tc is the coil rise time c207 is the capacity of the capacitor 2070. Figure 12 shows acceleration detection and correction of the closing angle when the force is at speed u. Comparator 2470 is amplifier 2
It is charged by the output current 1241 of the coil 410 to a voltage similar to the current waveform of the coil primary current I, and then charged through the resistor 2430. And the signal (A・T,)
It is reset by . Here, as shown in FIG. 12, when the closing angle is small and the coil primary current It is insufficient, the acceleration pulse ACC is output until the terminal voltage V247 reaches V248 after ignition, and during this ACC period,
The current 1211 quickly discharges the capacitor 2070. As a result, the current 1207 rapidly decreases to bring forward the next energization start time. The value of resistor 2430, along with capacitor 2470, is selected to simulate the start-up characteristics of the ignition coil. Also, the voltage ■248 is the primary current 1. The potential is set slightly lower than the potential corresponding to the constant current value, taking into account fluctuations in circuit elements.

[Effects of the present invention]

The ignition control device for an internal combustion engine according to the present invention performs 1iTl current time control of the ignition coil, and charges a capacitor in accordance with the rise characteristics of the negative current, generates an acceleration pulse in accordance with this charging waveform, Since the energization time is made longer, the ignition coil energization time jln can be accurately, reliably, and inexpensively realized even during acceleration.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a conventional ignition control device for an internal combustion engine, FIG. 2 is a diagram showing signal waveforms of the main parts of the device in FIG. 1, and FIG. 3 is an ignition control device for an internal combustion engine according to the present invention. A diagram showing the configuration of the device, FIG. 4 is a diagram showing the process of generating the ignition output signal from the reference position signal in the device of the present invention, and FIGS. Flowchart for explaining the main routine and interrupt routine, FIG. 6 is a diagram showing the relationship between Tvm Va, FIG. 7 is a diagram showing the relationship between TOFF Vl+, and FIG. 8 is an electric circuit of the control circuit in the device of the present invention. FIG. 9 is a diagram showing signal waveforms of the main parts of the device of the present invention, and FIGS. 10 (a) and (b) are signal waveforms showing a state in which the constant current time by closing angle calculation converges to the set value. 11 is a signal waveform diagram for explaining that the constant current time is controlled to a set value, and FIG. 12 is a diagram showing acceleration detection and correction of the closing angle during acceleration. 10.・Reference position signal generator, 20... Various sensors, 30... Ignition coil, 50... Battery, 60...
...Spark plug, 100...Calculating means, 200...
Control means, 2230... Resistor forming an impedance element, 2410... Amplifier, 2430... Resistor, 24
50...Switch, 2470...Capacitor, 24
80...Reference voltage, 2490...Comparator. Representative Patent Attorney Takashi Okabe Figure 1 Figure 2 and 2 Figure 5 (a) (b) Figure 9-11 Figure 10 (.) (b)

Claims (1)

[Claims] An ignition control device for an internal combustion engine that controls energization time of an ignition coil according to the rotational speed of the internal combustion engine, comprising: an impedance element for detecting a primary current of the ignition coil;
an amplifying means for amplifying the primary current waveform of the ignition coil that appears as a voltage drop across the impedance element; a time constant means including a capacitor charged to simulate the rise characteristic of the primary current of the ignition coil; and a comparison means for comparing a charging voltage waveform with a predetermined reference voltage value, and while a primary current is flowing through the ignition coil, the capacitor is connected to a voltage waveform similar to the primary current waveform of the ignition coil by the amplification means. At the same time, after the primary current of the ignition coil is cut off, the capacitor is continuously charged using the time constant of the time constant means, and an acceleration pulse having a pulse width corresponding to the acceleration state of the engine is obtained. An ignition control device for an internal combustion engine, characterized in that it corrects the energization time of an ignition coil to lengthen it.