JPS6140462A - Ignition controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent an ignition failure from occurring as well as to make improvements in safety, by installing a low engine speed detecting device, detecting a low engine speed state in an internal-combustion engine, and a constant current controlling device controlling a continuous rating current for an ignition coil to be set to the specified value. CONSTITUTION:An ignition control unit 100 generates a driving signal out of an ignition coil driving part 50 on the basis of a sensor signal out of a sensor part 10. This ignition control unit 100 consists of a filter circuit 110, an analog-to- digital converter 120, a central processing unit 130, a waveform shaping circuit 140, a backup circuit 200, etc. From this backup circuit 200, an ignition timing signal is outputted to a power transistor constant current control circuit 60, whereby a continuous rating current for an ignition coil 70 is controlled at this control circuit 60. Thus, in time of starting of an internal-combustion engine or its driving at low speed, any ignition failure based on generation of heat and breakdown in the power transistor or the like driving the ignition coil is preventable from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an internal combustion IIA control point control device, and more particularly to control of the flow of 14ff to the ignition coil at the time of starting or low speed rotation of the internal combustion IaII.

[Prior art]

In recent years, in order to respond to the miniaturization of ignition coils and the increase in speed of engines, there has been a trend to increase the current applied to the ignition coil and shorten the energization time. As a technique for controlling the energization time to the ignition coil to a constant time according to the battery voltage using an arithmetic control 211 device using a microcomputer, for example, a control device described in Japanese Patent Laid-Open No. 55-54669 is known. It is being

However, in an arithmetic and control device that controls the energization time using a microcomputer, it is necessary to ensure a function to cut off energization to the ignition coil when the microcomputer goes out of control. Therefore, it may be possible to replace the backup function with a timer circuit that guarantees another aspect of cutting off current to the ignition coil, but in order to cover the destruction of the power transistor due to overcurrent or the deterioration of ignition performance due to undercurrent, If the timer circuit does not have the function of changing the control of the energization time to the coil for a fixed period of time in accordance with the battery voltage, there is a problem that it cannot serve as a guarantee circuit that serves as a backup circuit.

[Problem that the invention seeks to solve]

The present invention has been made in order to solve the above-mentioned problems, and is an ignition control device for an internal combustion engine in which an arithmetic control device controls the energization start timing of an ignition coil and the ignition timing. This system aims to improve the safety of the ignition control device by limiting the current flowing to the ignition coil when driving at low speeds to prevent ignition failures due to heat generation or destruction of the power transistors that drive the ignition coil. It is.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides an ignition control device for an internal combustion engine that controls the start timing of the ignition coil and the ignition timing by calculating from a predetermined crank of the internal combustion engine. This ignition control device for an internal combustion engine is characterized by having a low-speed rotation detection means for detecting a low-speed rotation state, and a constant current control means for controlling the energizing current of an ignition coil to a predetermined current value when low-speed rotation is detected.

〔Example〕· Embodiments of the present invention will be described with reference to the accompanying drawings.

1 to 4 are block diagrams of a first embodiment of the present invention. FIG. 1 is a block diagram showing the whole of the embodiment, including a sensor section 10, an engine control unit 100,
It consists of an ignition coil drive section 5o.

The sensor unit 10 includes a starter switch 1 for driving an engine starting device attached to the engine, and a load detection sensor 2 for detecting the load state of the engine.
For example, intake air port sensor, intake pipe pressure sensor, etc.)
Reference position detection that detects the reference position of the crankshaft (for example, top dead center position) using battery voltage 3 for detecting a terminal voltage signal of a battery (not shown) and a signal from a rotation angle sensor that rotates in synchronization with the rotation of the engine. A sensor (G sensor) 4, and an angle detection sensor (N sensor) 5 that similarly to the G sensor 4 detects the angular position of the crankshaft (for example, a position every 30" CA) using a signal from an engine rotation angle sensor. Consists of.

The ignition control unit 100 is an arithmetic and control device that generates a drive signal for the ignition coil drive section 50 based on a sensor signal from the sensor section 10 .

The ignition control unit 100 includes a filter circuit 110, A-
D converter 120, CPU 130, waveform shaping circuit 140,
Consists of a backup circuit 200, etc., and a filter circuit 11
0, signals from the load detection sensor 2 and battery voltage 3 are input, and the filtered signal from which noise has been removed by the filter circuit 110 is input to the A/D conversion circuit 120 and converted into a digital signal. So, finally CPU13
It is taken into 0. On the other hand, the waveform shaping circuit 140 has G
The signals from the sensor 4 and the N sensor 5 are input, and the signals after being waveform-shaped by the waveform shaping circuit 140 are sent to the CPU 130.
and the backup circuit 200, respectively.

The backup circuit 200 receives the signal from the starter switch 1 and the ignition timing calculation signal (IGt) from the CPU 130 and outputs the final ignition timing signal to the power transistor constant current 'aJm circuit 60 of the ignition coil drive unit 50.
Ignition coil 7 with power transistor constant current control circuit 60
The configuration is such that the current flowing to zero is controlled. That is, in order to protect the power transistor in the power transistor constant current control circuit 6o from overcurrent, the ignition coil charging current is controlled to be constant when the current exceeds a certain current value.

Next, referring to FIG. 2, the inside of the backup circuit 200 will be explained. The backup circuit 200 includes a reference angle signal generation circuit 210, a charging/discharging circuit 2201, an ON point advance circuit 23o1, a start determination circuit 24010, a sick circuit 250
, a backup mode detection and IGt signal switching circuit 260, and the like.

The reference angle signal generation circuit 210 receives the G signal from the G sensor 4 and the N signal from the N sensor 5 through the cables 141 and 1.
42. Reference angle signal generation circuit 210
As output signals, (A) and (B) shown in FIG.
, (C) are output. (A) Signal is the ignition signal at startup, (8) Signal is the ignition signal at high speed (to guard the energization time at extremely high speed), (C) Signal is the charging period signal for the charge/discharge circuit. .

(A) The signal is input to the AND circuit 252 of the logic circuit 250, and (B) the signal is input to the other AND circuit 251.
C) The signals are respectively input to the charging/discharging circuit 220.

(C) The charging/discharging voltage signal from the charging/discharging circuit 220 to which the signal has been input is input to the ON point advance circuit 230 and the start determination circuit 240, respectively.

The signal from the ON point advance circuit 230 ([E] times signal is
The signal is input to an AND circuit 251, where the CB) signal and the (E) signal are subjected to logical AND processing, and the output signal ([F] times the signal) is input to an AND circuit 254.

The D signal from the charge/discharge circuit 220 and the output signal of the starter switch 1 are input to the start determination circuit 240, and the signal from the circuit 240 is input to the AND circuit 254 through an AND circuit 252 and an inverter circuit 253. be done.

Furthermore, a CF) signal is input to the other terminal of the AND circuit 254. Output of AND circuit 252 and AND circuit 2
54 is input to an OR circuit 255, and the output signal of this OR circuit 255 is used for backup mode detection and IG detection through a cable 154.
The signal is input to the t signal switching circuit 260. The circuit 280 also receives an ignition timing calculation signal (r
Gt signal) is input through the cable 131. In addition, the G signal through the cable 152 and the start determination signal from the start determination circuit 240 through the cable 153 are also transmitted to the backup mode detection and IGt signal switching circuit 260.
and is input to the power transistor constant current control circuit 60. The output signal of the circuit 260 is:

It is connected to the power transistor constant current control circuit 60 through a cable 151.

Referring to FIG. 3, the internal structure of the backup mode detection and IGt signal switching circuit 260 will be described. First, the ignition timing calculation signal (IGt signal) from the CPU 130 is sent to the fail counter 261 through the cable 131.
and the (a) terminal of the data selector 264.

The cable 15 is connected to the (b) terminal of the data selector 264.
4, a fixed IGt signal at the time of fail is input.

Data select signal terminal (S) of data selector 264
The output of the O'R circuit 263 is input to the input of the OR circuit 263, and the output signal of the fail counter 261 (at the time of fail (when the high point signal is received other than the predetermined number of times), the output signal becomes H level). A signal held by a latch circuit 262 and a start determination signal passed through a Schmitt trigger 265 are input.A reset signal by a G signal 152 is input to the reset terminal of the fail counter 261 and the latch circuit 262. Ru.

Next, referring to FIG. 4, the internal configuration of the power transistor constant current control circuit 60 will be described.

An ignition signal is connected via a cable 151 to a power transistor 61 that turns on and off current to the ignition coil, and the emitter of the power transistor 61 is grounded via a resistor 62. The voltage at point R of the emitter is applied to a resistor 64.

In addition, a cable 155 is connected to the base of the transistor 63.
A start determination signal that has passed through an inverter 65 is input from the inverter 65 . Further, the signal after the resistor 64 is input to the collector. On the other hand, the voltage signal at point R via the resistor 64 is input to the base of the transistor 66, and
The collector of transistor 61 and the base of transistor 61 are connected at eight points.

[Effect]

Next, the operation of the control device of the first embodiment will be explained.

First, the normal operation (excluding startup) of the control device will be explained with reference to FIGS. 1 to 5.

In diagram M1, load detection sensor 2 and battery voltage 3
A filter circuit 110 removes noise components from each of the load signal and battery voltage signal sent from A-
A-to-D conversion is performed by the D conversion circuit 120, and the data is read as information by the CPU 130. The G sensor signal from the reference position detection sensor (G sensor) 4 and the angle detection sensor (N sensor) 5 [Fig. 5 (a)] and the N sensor signal (Fig. 5 (b))
) is waveform-shaped by the waveform-shaping circuit 140, and the signal after waveform-shaping is input to the CPU 130, which detects the operating state of the engine based on the information on the load signal and battery voltage signal, and determines the optimal ignition timing and A control value for the ignition coil filling time is determined, and as a result of the calculation, an ignition coil drive signal (IGt signal) is output from the CPU 130 and sent to the backup circuit 260 through the cable 131. In the backup circuit 200, when the CPU 130 is normal, the data selector 264 of the backup mode detection and IGt signal switching circuit 260 selects CPL1.
The calculated ignition signal (IGt signal) of 130 is connected to the cable 131
The signal is sent to the power transistor constant m current control circuit 60 via the cable 151 from the input terminal (a) of the data selector 264 to the output terminal (OLIT). and,
The ignition signal during backup is input to the input terminal (b) of the data selector 264, but is not output. The signal in FIG. 5 (H) shows the calculated ignition signal (IGt signal) from the CPL 1130 during normal operation. Jl indicates the coil charging start timing, and J2 indicates the ignition timing.

Next, the operation of the ignition control device of the first embodiment during backup and startup will be explained with reference to the time charts of the backup circuit 200 shown in FIGS. 1 to 4 and 5. First, to explain the operation under normal operating conditions (for example, 40 Kb) based on FIG. 1, the G signal and N signal based on the G sensor 4 and N sensor 5 are
At 40, the signal after waveform shaping is input to the reference angle signal generation circuit 210 of the backup circuit 200, and the signals (A), (B), and (C) shown in FIG. 5 are generated from the circuit 210. Among these, when the (C) signal is at H level, that is, BT
During the period of 60° CA between 30° and 70° of DCl, a capacitor (not shown) of the charging/discharging circuit 220 is charged with a constant charging current of 1° in the charging/discharging circuit 220 of the backup circuit 200 shown in FIG. 2. This charging period is BT
DCl 30° to 70°CΔ, BTDC 70°C
After passing A, the charging current becomes i.

The discharge current i has the same value as . Discharge is performed with BTDClo
The discharge is configured to end at oCA. The voltage of this charging/discharging capacitor is (D) torpedo pressure and is shown in FIG. That is, (D) torpedo pressure increases from BTDC130° with electric R1°, reaches the maximum value at BTDC70°CA, and discharge current i rises to BTDClooGA. continues to decrease. 8
A triangular wave with an equal slope having a peak value at TDC 70° CA and a maximum value inversely proportional to the engine speed is formed.

(D) The torpedo pressure signal is sent to the ON point advance circuit 230.
and is output to the start determination circuit 240.

(D) In the ON point advance circuit 230 that receives the torpedo pressure signal, a predetermined threshold voltage V (variable according to the old battery voltage 1, and when the battery voltage is high, the threshold voltage Th1 is set low, and when the battery voltage is low, Threshold voltage (Th1 is high) is compared with (D) torpedo pressure to create an ON point advance signal ([E] times signal. Next, the (E) signal and (B) signal are combined in an AND circuit 251. A logical product is taken, and the output becomes the ignition signal (F) signal at the time of backup.

Next, in high-speed operating conditions, the maximum value of (D) torpedo pressure decreases as the engine speed increases.

That is, the charging current is 1°, which is the same even at low speeds, but as the engine rotational speed increases, the charging time becomes shorter. (D) If the maximum value of the torpedo pressure becomes lower, the coil charging start timing should be advanced; however, if the engine speed further increases, (D) the torpedo pressure also becomes lower. Then, a condition arises where the voltage becomes lower than the threshold voltage VTh1.

However, the threshold voltage Th1 must be set above a predetermined noise-proof voltage value in consideration of noise resistance, etc., so the coil charging can be started by comparing the threshold voltage ■ and (D) Torpedo ■ old pressure. There are certain limits to determining the timing due to the relationship with the engine rotation speed. To prevent this, from the threshold voltage V1h1 (D)
Under conditions where the torpedo pressure is low, the (E) signal in FIG. 2 is set to H level, and the (B) signal is configured so as to serve as the ignition signal during backup. That is, the energization time guard control is performed even at high speeds.

Next, the operation at startup will be explained. To determine whether to start the engine, the signal from the starter switch 1 is determined by the start determination circuit 240, but the following control is performed assuming that the starter is not used (for example, in a push state). At startup, since the engine rotation speed is slow, the (C) signal (charging period signal = 60° CA - window) becomes longer in terms of time, so the (D) torpedo pressure (charging voltage) R high point increases.

That is, by comparing the threshold voltage (V) (at the time of starting, for example, at a voltage of about 35 Orpm with engine speed) and (D) torpedo pressure, in the starting determination circuit 240. Start determination becomes possible. When the start determination circuit 240 determines that the engine is in the start state, the (A) signal is outputted from the cable 154 as a full ignition signal. The switching of the ignition signal to this starting state is performed by the logic circuit 250. Start determination circuit 240
If it is determined that it is in the starting state, or (the same applies even if the starter switch 1 is in the ON state), the starting determination circuit 24o,
8, HL/ < )Li (7) (g @ M B3 ka 8° 6° 15- The (A) signal from the AND circuit 252 is input to the OR circuit 255. Also, the A, ND circuit 264 Since an L level signal is input, (, F
) signal does not become an input to the OR circuit 255.

Furthermore, when the engine is not in the starting state, the starting determination circuit 240 outputs an L level signal, so that (A)
The signal is masked by the AND circuit 252, and conversely, the (F) signal is output from the AND circuit 254, and the (F) signal becomes the ignition signal.

Next, the operation of the backup mode detection and IGt signal switching circuit 26o will be explained using FIG.

The setting conditions for switching to backup mode are CPU1
If the calculated ignition signal (IGt signal) from 30 differs from the predetermined number of ignitions (more or less, it is judged as a failure), the battery voltage is low and the engine speed fluctuation is very large, so the calculation by the CPU 130 is During difficult starts,
This is the case under the condition.

First, the processing when the ignition signal is abnormal will be explained. An ignition timing signal (IQt signal) from the CPU 130 is input from the cable 131 to the fail counter 261 . Furthermore, a G signal is input as a reset signal for the counter 261. That is, if there is no predetermined number of ignitions within the interval of the G signal, the fail counter 261 outputs an H level signal, and the next latch 262 holds the predetermined interval. Since the circuit 260 is reset by the G signal, it is held at the interval of the G signal. This held signal passes through the OR circuit 263 and the data selector 264.
is input to the select terminal (S) of. In addition, at the time of starting (during cranking by the starter or when the engine rotation speed is extremely low (approximately 35 Orpm or less)), the start determination signal (signal at H level at the time of starting) passes through the Schmitt trigger circuit 265 and the OR circuit 263. Similarly, data selector 264
is input to the select terminal (S) of. That is, in the event of a failure, the switch in the data selector 264 will fall toward the (b) terminal, and the fixed IGt signal will be transferred to the cable 15 in the event of a failure.
Sent to 1. In addition, under normal conditions, the switch in the data selector 264 falls toward the (a) terminal, and the CPU 1
The ignition calculation signal (IGt signal) from 30 is connected to cable 15
Sent to 1.

Next, the operation of the power transistor drive control circuit 60 will be explained using FIG. 4.

First, when starting the engine, the cable 155 is
The 1″ signal of the start determination signal is input, and the inverter 65
is inverted to turn off the transistor 63. Here, the ignition signal (IGt signal) is sent to the power transistor 61 through the cable 151 to turn on and off the energizing current of the ignition coil.

When a current flows through the power transistor 61, the resistor 6
2 is also energized, the voltage at point R increases, and a voltage signal corresponding to the energized current is generated at point R. The voltage at the R point is sent to the base of the transistor 66 through the resistor 64, and when the R point voltage exceeds a certain level, the transistor 66
becomes an ON pole, absorbs the base current of the eight power transistors 61, and controls the collector current of the power transistor 61 (current flowing through the ignition coil). That is, the sixth
As shown in the figure, when the current flowing through the ignition coil exceeds a certain value, a limiter is applied to control the current to a constant value. Next, except when starting, cable 15
Since the start determination signal 1101+ is inputted from 5 to 1101+, and the transistor 63 is turned on, no voltage signal is sent to the transistor 66. That is, control of the applied current is not performed.

FIG. 7 shows control characteristics of the energization time of the ignition coil and the ignition timing at the time of starting the engine of the embodiment.

According to this embodiment, the low speed rotation state of the engine, such as starting or low speed running, is detected, and the BTDC is 130° to 10° during low speed rotation or backup.
The charging/discharging current i with BTDC70° as the peak. A triangular wave is formed as a charging/discharging waveform having a peak value according to the rotational speed of the engine, and an ignition signal at the time of backup is made based on a signal obtained by comparing the charging/discharging waveform with a voltage value according to the battery voltage. The current applied to the ignition coil is limited to a predetermined current value when the engine starts or rotates at low speed. This prevents excessive current from flowing to the ignition coil even when starting and driving at low speeds, and prevents ignition failures due to overheating and destruction of the power transistors that drive the ignition coil, thereby ensuring the safety of the ignition control device. can improve sex.

Next, a second embodiment of the present invention will be described with reference to FIG.

In FIG. 8, the basic configuration is almost the same as that of the first embodiment shown in FIG. In the second embodiment, a low voltage discrimination circuit 160 is added to J5 to detect that the battery voltage 3 has decreased extremely. In this embodiment, when the battery voltage 3 is extremely high, the backup circuit that receives this signal is also ≠ the starter switch signal @ (starting determination signal).
And the low speed rotation signal due to the engine rotation obtained from the N sensor and the battery voltage drop signal are taken out by an OR circuit,
The configuration is such that the signal is sent to the power transistor constant current drive control circuit 60 through a cable 152.

According to this embodiment, even if the battery voltage 3 is extremely reduced, the current flowing through the power 1 to the radiator 1 can be controlled to a constant current to prevent heat generation and destruction due to excessive current in the power 1 to the radiator 1. .

〔Effect of the invention〕

According to the present invention, in an ignition control device for an internal combustion engine in which the energization start timing and ignition timing of the ignition coil are controlled by the performance control device, the current applied to the ignition coil is controlled when the internal combustion engine is started or when running at low speed. By controlling the current to a constant value, it is possible to prevent ignition failures due to heat generation and destruction of the power transistor that drives the ignition coil, thereby improving the safety of the ignition control device.

[Brief explanation of drawings]

FIG. 1 is an overall block diagram of an ignition control device according to a first embodiment of the present invention. FIG. 2 is a block diagram of the backup circuit of the same embodiment. FIG. 3 shows backup mode detection and IG of the same embodiment.
FIG. 3 is a block diagram of a t signal switching circuit. FIG. 4 is a block diagram of the ignition coil constant current control circuit of the same embodiment. FIG. 5 is a time chart in the backup circuit of the same embodiment. FIG. 6 is a time chart showing the ignition timing at the time of starting the same embodiment. FIG. 7 is a characteristic diagram showing the ignition timing characteristics at the time of starting of the same embodiment. FIG. 8 is an overall block diagram of a second embodiment of the present invention. (Explanation of symbols) 1...Starter switch 2...Load detection sensor 3...Battery voltage 4...Reference position detection sensor (G sensor) 5...Angle detection sensor (N sensor) 10... -Sensor section 50...Ignition coil drive section 60...Power transistor constant current control circuit 61...
・Power transistor 70...Ignition coil 100...Control unit section 110...Filter circuit 120...A/D circuit 130...CPU 140...Waveform shaping circuit 200...Backup circuit 210... ...Reference angle signal generation circuit 220...Charging/discharging circuit 230...ON point advance circuit 240...Start determination circuit 250...Logic circuit 260...Backup mode detection and IGt signal switching circuit 261...・Fail counter 264...Data selector representative Akira Asamura 1st 4th
Figure 5 J, J2 Figure 6

Claims (4)

[Claims] (1) An ignition control device for an internal combustion engine that controls energization start timing and ignition timing of an ignition coil by calculating from a predetermined crank of the internal combustion engine, comprising: low-speed rotation detection means for detecting a low-speed rotation state of the internal combustion engine; An ignition control device for an internal combustion engine, comprising: constant current control means for controlling the current flowing through the ignition coil to a predetermined current value when low speed rotation is detected. (2) The ignition control device for an internal combustion engine according to claim 1, wherein the low speed rotation detection means is a start discrimination means for detecting a low speed rotation state at the time of starting the internal combustion engine. (3) The ignition control device for an internal combustion engine according to claim 1, wherein the low speed rotation detection means is a low speed operation detection means for detecting a low battery voltage state of the internal combustion engine. (4) In the description of claim 1, the low-speed rotation detection means includes both a start-up determination means for detecting when the internal combustion engine is started and a low-speed operation detection means for detecting the low-speed operation state of the internal combustion engine. The ignition control device for an internal combustion engine.