JPH01208568A - Ignition device for internal combustion engine - Google Patents

Abstract

PURPOSE:To carry out stable ignition irrespective of variation in rotation, etc., at the time of starting an internal combustion engine and improve a starting property by delaying the ignition timing of an ignition signal at the time of detecting a source voltage lower than a reference value. CONSTITUTION:A rotation angle sensor 11 outputs pulse signals at the defined rotation angle interval of an internal combustion engine and a means 1 outputs a detected signal corresponding to the operating condition of the internal combustion engine. On the other hand, a means 2 operates an ignition timing. A means 3 outputs an ignition control signal based on the output pulses of the rotation angle sensor 11 at the time of starting while based on the output signal of the means 1 at an ordinary time. A means 4 controls the primary current of an ignition coil based on the ignition control signal from the means 3. In this device, when a source voltage is below a reference value, a means 5 outputs a detected signal. While the detected signal is being outputted from the means 5, a means 6 delays an ignition timing.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an arithmetic control device that calculates and outputs an optimal ignition control signal according to the operating state of an internal combustion engine, and an ignition control signal from the arithmetic control device. The present invention relates to an ignition device for an internal combustion engine that controls the primary current of an ignition coil based on the above, and more particularly to an ignition device for an internal combustion engine that satisfactorily controls the primary current at the time of starting the internal combustion engine.

[Prior Art] Conventionally, signals from various sensors for determining various operating states of an internal combustion engine, such as a rotation angle sensor, a cooling water temperature sensor, and an intake pipe pressure sensor, have been transmitted to a microcomputer (hereinafter referred to as M
This MPU calculates and outputs the ignition control signal, and also controls signals in areas where the control by the MPU is unstable, i.e. when the power supply voltage drops and the MPU becomes unstable, or when rotational fluctuations are large. When starting an internal combustion engine or at low rotation speeds, when calculation accuracy cannot be achieved due to
In order to obtain stable ignition and to maintain operation of the internal combustion engine even in the event of MPU failure, the ignition is configured to output a fixed ignition timing signal at a substantially constant angle synchronized with the rotation angle signal of the rotation angle sensor. The timing control method was published in Japanese Patent Application Laid-open No. 1983-
It is disclosed in No. 49069.

[Problem to be Solved by the Invention 1] However, in the above method, if the fixed ignition timing signal is set to the advance side, the ignition timing may be too early and knocking may occur, or the ignition timing may act on the piston that is rising during the compression stroke. There is a problem in that the reverse torque causes deterioration in starting performance. In addition, if the fixed ignition timing signal is set to the retarded side, when the rotational speed of the internal combustion engine increases in the event of an MPU failure, combustion will end in the expansion stroke, and combustion energy will appear as heat, causing an increase in exhaust temperature and torque. There is a problem that a shortage may occur.

This invention was made to solve the above-mentioned problems, and its purpose is to obtain stable ignition especially under adverse conditions such as large rotational fluctuations when starting an internal combustion engine and a drop in power supply voltage. An object of the present invention is to provide an ignition device for an internal combustion engine that can improve starting performance.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a rotation angle sensor 11 that outputs a pulse signal at predetermined rotation angle intervals of an internal combustion engine, and a rotation angle sensor 11 that outputs a pulse signal at predetermined rotation angle intervals of an internal combustion engine, as shown in FIG. an operating state detecting means 1 for outputting a detection signal corresponding to the rotation angle sensor 1; a calculating means 2 for calculating the ignition timing based on the signals from the rotation angle sensor 11 and the operating state detecting means 1; Based on the output pulse from the angle sensor 11,
During normal operation of the internal combustion engine, a control signal generating means 3 outputs an ignition control signal based on the output signal from the arithmetic means 2; An ignition device for an internal combustion engine that includes an ignition control means 4 that controls current, a voltage detection means 5 that outputs a detection signal when the power supply voltage is below a preset reference voltage, and a voltage detection means 5 that outputs a detection signal when the internal combustion engine is started. an ignition retard for retarding the ignition timing of the ignition signal output from the ignition control means 4 when the control signal generation means 3 outputs the ignition control signal when the detection signal is output from the means 5; The gist of this invention is an ignition system for an internal combustion engine equipped with corner means 6.

[Operation] Therefore, when the internal combustion engine is rotated and the power supply voltage becomes less than or equal to a preset reference voltage, the voltage detection means outputs a detection signal. Further, as the internal combustion engine rotates, the rotation angle sensor outputs a pulse signal at predetermined angular intervals, and the calculation means calculates the ignition timing based on the pulse signal and the operating state of the internal combustion engine. When the internal combustion engine is started, when the control signal generating means outputs an ignition control signal based on the output pulse of the rotation angle sensor, the ignition control means controls the primary current of the ignition coil based on this ignition control signal. . If the ignition control signal is output while the voltage detection means is outputting a detection signal, the ignition retard means retards the ignition timing of the ignition signal output from the ignition control means.

Further, during normal operation of the internal combustion engine, an ignition control signal is output from the control signal generation means based on the output signal of the calculation means,
Based on this ignition control signal, the ignition control means controls the primary current of the ignition coil.

[Example] An example embodying the present invention will be described below with reference to FIGS. 2 to 4.

Figure 2 shows the electrical configuration of the ignition system, and the control device 10 includes a rotor that rotates in synchronization with the engine camshaft and has protrusions equal to the number of cylinders, and generates pulses at equal angular intervals based on the rotation of the rotor. A rotation angle sensor 11 consisting of a magnetic pickup is connected, and its output pulse SGI is inputted via a waveform shaping circuit 12 to a microcomputer (hereinafter referred to as MPU) 13 serving as a calculation means.

Further, connected to the control device 10 are an intake air amount sensor 14 that detects the intake air amount, a cooling water temperature sensor 15 that detects the engine cooling water temperature and outputs a water temperature signal, and a battery voltage sensor 16 that detects the battery voltage. In this embodiment, the intake air amount sensor 14, the cooling water temperature sensor 15, and the battery voltage sensor 16 constitute an operating state detection means. Analog output signals from each of the sensors 14 to 16 are input to an A/D converter 17, and the A/D converter 17 converts the analog signals from each of the sensors 14 to I6 into a digital signal and outputs the digital signal to the MPU 13. It has become.

Furthermore, a starter switch 19 that outputs a detection signal SG2 when the start key is rotated to the starter position is connected to the control device 10, and the voltage level of the output signal of this switch 19 is converted by a buffer 20 and sent to the MPU 13. It has been entered.

The MPU 13 is a read-only memory (ROM) in which arithmetic circuits, control programs, and initial data are stored in advance.
), and a random access memory (RAM) in which various signals input to the MPU 13 and data necessary for calculation control are temporarily stored, and the MPU 13 receives input signals from the sensors 11, 14 to 16. The ignition timing is calculated based on the ignition timing, and an output signal SG3 is output.

, the output signal SG3 of the MPU 13 is connected to a signal selection circuit 21 as a control signal generating means, and the output pulse S of the rotation angle sensor 11 is connected to this signal selection circuit 21.
G1, and the detection signal SG2 of the starter switch 19
is now entered. This signal selection circuit 21 normally uses an output signal S output from the MPU 13.
G3 is selected and the engine is started when the detection signal SG2 of the starter switch 19 is input, or when the MPU 13 is out of order, the number of output pulses SGI from the rotation angle sensor 11 and the output signal SG3 from the MPU 13 are selected. When the number of pulses does not match, rotation angle sensor 1
1 output pulse SGI is selected, and an ignition control signal SG4 as shown in FIG. 4(a) is output.

An igniter 22 as ignition control means is connected to the signal selection circuit 21, and an ignition coil 23 that supplies ignition energy to a spark plug (not shown) provided for each cylinder of the engine is connected to the igniter 22. . The igniter 22 controls the energization of the ignition coil 23 based on the ignition control signal SG4.

Next, the igniter 22 will be explained in detail based on FIG. 3.

The ignition control signal SG4 is input to the closing angle control circuit 24 of the igniter 22.
calculates the next ignition coil ON time from the input cycle of the previous ignition control signal SG4 and the previous battery voltage 8, and outputs the ignition signal IGt as shown in Fig. 4 (el). The rising edge of IGt corresponds to the ignition control signal S.
It is faster than the rise of G4.

The output terminal 24a of the closed angle control circuit 24 is connected to one input terminal of an OR circuit 25, and the output of the OR circuit 25 is connected to the base terminal of a power transistor 27 via a drive circuit 26. A collector terminal of the power transistor 27 is connected to one end of the primary side of the ignition coil 23. Then, the drive circuit 26 turns on the power transistor 27 in synchronization with the rising edge of the ignition signal IGt, and the primary current 1 is supplied to the ignition coil 23 from the battery voltage vB.
1, the power transistor 27 is turned off in synchronization with the falling edge of the ignition signal IGt, the primary current 11 is cut off, and a secondary voltage is generated. As a result, the primary current 11 of the ignition coil 23 can obtain a secondary generated voltage sufficient to ignite each of the spark plugs,
Moreover, the primary current 11 is prevented from becoming excessive.

In addition, a resistor 2 is connected to the emitter terminal of the power transistor 27.
8 is connected, and a voltage Vr upstream of this resistor 28 is applied to one input terminal of a comparator 29. The other input terminal of the comparator 29 is connected to the downstream side of the resistor 28 via a regulator 30 that sets the reference voltage (1). Then, the comparator 29 compares the voltage Vr with the reference voltage Vl, and when the voltage Vr becomes equal to or higher than the reference voltage 71, outputs a high-level monitor signal ■C8T to the MPU 13 indicating that the igniter 22 is in good condition. It has become.

Further, the ignition control signal SG4 bypasses the closing angle control circuit 24 and is input to one input terminal of an OR circuit 31, and the output of the OR circuit 31 is connected to the other input terminal of the OR circuit 25. . Thereby, even if the closing angle control circuit 24 fails, the ignition control signal SG4 can be outputted to the drive circuit 26 via the OR circuit 31.25.

On the other hand, the other end of the ignition coil 23 is connected to one input terminal of a comparator 32 as a voltage detection means, to which the battery voltage V3 is applied, and the other input terminal is connected to a regulator 33 that sets the determination voltage 2. is connected. Then, the comparator 32 outputs the battery voltage Va
and the judgment voltage v2, and when the battery voltage vB≦the judgment voltage v2, a high-level monitor signal SG5 as shown in FIG. 4 (C1) is output.

The monitor signal SG5 of the comparator 32 is inverted via the inverter 34 and then input to the reset terminal 35a of a flip-flop 35 serving as ignition retard means. Also, the trigger terminal 3 of this flip-flop 35
The ignition control signal 0 SG4 is inputted to 5b, and the output terminal 35c is connected to the other input terminal of the OR circuit 31. When the inverter 34 outputs a low level signal, that is, when the comparator 32 outputs the monitor signal SG5, the flip-flop 35 outputs the ignition control signal S.
When there is an input of G4, a retard signal SG6 as shown in FIG. 4 (dl) is output.

Next, the operation of the ignition device configured as described above will be explained.

Starter switch 1 based on engine key ° rotation operation.
9 is turned on, battery voltage V3 is supplied to the starter motor (as shown), and cranking of the engine is started. At the moment when the starter motor starts, the engine speed is 0, so a large load is applied to the starter motor and a large current flows, causing the battery voltage vB to increase as shown in Figure 4 (bl). Judgment voltage v2
Thereafter, the magnitude of the starter current changes depending on the cranking rotation speed, and the battery voltage vB changes correspondingly.

The cranking speed is determined by the engine's friction and the torque characteristics of the starter motor. Near the compression top dead center of the engine, the compression pressure of the air-fuel mixture overlaps with the opening of the intake and exhaust valves, so the friction increases. In addition, the torque of the DC motor used in the starter motor is proportional to the current, so when the engine starts cranking, the starter motor current increases and the battery voltage v
B decreases.

During cranking, the battery voltage vB is the judgment voltage■
2 or less, the comparator 32 outputs a high-level monitor signal SG5 as shown in FIG. 4(C).
is output and while this monitor signal SG5 is being generated,
Operation of flip-flop 35 is allowed.

On the other hand, when cranking is started and the engine begins to rotate, the rotation angle sensor 11
Output pulse SGl is output from. At this time, since the starter switch 19 is in the on state, the output pulse SGI is selected by the signal selection circuit 21, and the ignition control signal SG4 shown in FIG. and is output to the flip-flop 35.

When the ignition control signal SG4 is input during the period when the monitor signal SG5 is outputted from the comparator 32 and the flip-flop 35 is operable, the flip-flop 35 is triggered at its rising edge, and the flip-flop 35 is triggered from the output terminal 35c as shown in FIG. A high-level retard signal SG6 shown in is output. This retard signal SG6 is output until the monitor signal SG5 is no longer output from the comparator 32 and a high level signal is input from the inverter 34 to the reset terminal 35a to reset the flip-flop 35. As a result, the OR circuit 25 outputs the ignition signal IGt up to the position where the battery voltage vB returns to the determination voltage (2) as shown in FIG. 4 (el).
The power transistor 27 is activated by the drive circuit 26 based on t.
is controlled on and off, and the primary current 11 of the ignition coil 230 is cut off based on the OFF state of the power transistor 27, and ignition for starting is performed.

In addition, when the engine is stopped or is being operated at a predetermined speed or higher, the battery voltage vB is as shown in Fig. 4(b).
Since it is higher than the judgment voltage ■2 shown in , the comparator 32
The output of the inverter 34 becomes a low level, the output of the inverter 34 becomes a high level, and the flip-flop 35 is reset and its operation is prohibited. Also, since the starter switch 19 is in the off state, the signal selection circuit 21 outputs the signal from the MPU 13.
The output signal SG3 is output as the ignition control signal SG4, and the primary current (1) of the ignition coil 23 is controlled based on the ignition signal rGt output from the closed angle control circuit 24, and the ignition timing is also controlled according to the ignition signal IGt. Determined by input.

Note that when the MPU 13 fails, the signal selection circuit 21 selects the output pulse SGI of the rotation angle sensor 11 and outputs it as the ignition control signal SG4.
Ignition timing control is performed by the ignition signal IGt output from the closing angle control circuit 24 based on the input of No. 4.

In this way, in this embodiment, the fixed ignition timing determined by the output pulse SGI of the rotation angle sensor 11 is retarded until the battery voltage vB, which fluctuates depending on the cranking speed, returns to the determination voltage (2) when starting the engine. This makes it possible to prevent the occurrence of knocking and to improve startability without applying reverse torque to the piston during the upward movement of the compression stroke.

In the embodiment described above, the monitor signal SG5 was created using one judgment voltage (2) for the battery voltage vB, but the voltage at the permission level for permitting the operation of the flip-flop 35 and the voltage at the permission level for prohibiting the operation of the flip-flop 35 are used. The determination may be made using two determination voltages of the recovery level. Alternatively, a voltage at a permission level for permitting the operation of the flip-flop 35 may be set, and the operation of the flip-flop 35 may be prohibited by a predetermined hysteresis.

Furthermore, instead of the flip-flop 35, a relay circuit may be used as the ignition retarding means, which delays the generation of the ignition control signal SG4 for a predetermined period when the monitor signal SG5 is at a high level.

Furthermore, the closing angle control circuit 24 and the OR circuit 31 in the above embodiment are omitted, and the OR circuit 25 logically ORs the ignition signal whose closing angle is directly controlled by the MPU 13 and the output of the flip-flop 35 and outputs the result. It may be configured to do so.

[Effects of the Invention] As described in detail above, according to the present invention, stable ignition can be obtained under adverse conditions such as large rotational fluctuations at the time of starting an internal combustion engine, a drop in power supply voltage, etc., and the starting performance is improved. There are excellent effects that can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to claims of this invention, FIG. 2 is a block diagram showing an electrical configuration of an embodiment embodying this invention,
FIG. 3 is a circuit diagram showing the electrical configuration of the igniter, and FIG. 4 is a waveform diagram for explaining the operation. In the figure, 1 is an operating state detection means, 2 is a calculation means, 3 is a control signal generation means, 4 is an ignition control means, 5 is a voltage detection means,
6 is an ignition retard means, and 11 is a rotation angle sensor.

Claims (1)

[Scope of Claims] 1. A rotation angle sensor that outputs a pulse signal at predetermined rotation angle intervals of the internal combustion engine; an operating state detection means that outputs a detection signal corresponding to the operating state of the internal combustion engine; and the rotation angle sensor and the operating state. a calculation means for calculating the ignition timing based on the signal from the state detection means; and, when starting the internal combustion engine, based on the output pulse from the rotation angle sensor;
control signal generation means for outputting an ignition control signal based on the output signal from the calculation means during normal operation of the internal combustion engine; and control signal generation means for controlling the primary current of the ignition coil based on the ignition control signal from the control signal generation means. An ignition device for an internal combustion engine, comprising: a voltage detection means that outputs a detection signal when the power supply voltage is below a preset reference voltage; and a detection signal from the voltage detection means when starting the internal combustion engine. and ignition retard means for retarding the ignition timing of the ignition signal output from the ignition control means when the ignition control signal is output from the control signal generation means. Characteristics of the ignition system for internal combustion engines.