JPH0578670B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ignition timing control device for an internal combustion engine, and particularly to an ignition timing control device for an ignition timing control device for an internal combustion engine. The present invention relates to an ignition timing control device that reduces heat generation in the engine.

[Conventional technology]

A conventional ignition device for an internal combustion engine of this kind is known, for example, from Japanese Patent Application Laid-open No. 56-23564, in which the primary current of the ignition coil is detected and a signal indicating the period in which a constant current is reached is output. The configuration is such that the on-time of the ignition coil is controlled by input, and a schematic diagram thereof is shown in FIG.

That is, a rotation sensor 1 that detects engine rotation, various sensors 2 that detect input information for controlling energization time, and a computing unit that inputs information from the rotation sensor 1, various sensors 2, and igniter 4 and calculates energization time. 3. An igniter 4 that directly drives the ignition coil 5 by power amplifying the output signal of the computing unit 3 and outputs a constant current signal when the primary current of the ignition coil reaches a certain constant value; an ignition device that receives the output of the igniter 4; The configuration includes a coil 5 and a plug 6 that receives the output of the ignition coil 5.

The control operation of the internal combustion engine ignition device shown in FIG. 5 follows the control flow shown in FIG. 6.

In FIG. 6, 3 indicates the above-mentioned arithmetic unit, and 31 to 37
indicates the operation steps of the arithmetic unit, in which the constant current time target value is detected in step 31 (Te), the previous constant current time is measured in step 32 (Ta), and the constant current time target value Te is determined in step 33. Last constant current time measurement value
Calculate the difference from Ta, calculate the correction amount according to the engine conditions in step 34, add the correction amount (Th) to the previous on time in step 36 (36 steps),
This is a method of outputting with priority given to off time (37 steps).

This will be explained in detail using the time chart shown in FIG.
Measure (Ta)i at time t ₁₀ , find the difference (Th)i from (Te)i, multiply (Th)i by the correction coefficient (K)i, add (To)i, and get (To)i. Outputs ₊₁ .

Measure (Ta)i ₊₁ at time t ₂₀ , find the difference (Th)i ₊₁ from (Te)i ₊₁ , and multiply (Th)i ₊₁ by the correction coefficient (K)i ₊₁ to obtain ( Add To)i ₊₁ and output (To)i ₊₂ .
The same control is repeated thereafter.

Next, a case where a primary current jump occurs will be explained with reference to FIG.

A jump is detected at time _t50 .

The detection method is calculated at time t ₄₀ (Th) i ₊₄ ^* (K)
Compare the i ₊₄ value and the (Ta)i ₊₅ value measured at time t ₅₀ , and if (Th)i ₊₄ ^* (K)i ₊₄ < (Ta)i ₊₅ , it is judged as a jump. Add (Th)i ₊₅ ^* (K)i _{+5 to (To)i +5} and output (To ₎ i ₊₆ .

[Problem that the invention seeks to solve]

Such conventional control methods have the following problems.

(1) When the jump is detected at time t ₅₀ , the ignition is already in a constant current period larger than the constant current target value (Te) i ₊₅ , and the ignition coil and the igniter for driving the ignition coil generate heat during this period. This will be an increasing factor.

(2) Since jump did not occur at time _t80 , there is a possibility of misfire due to insufficient primary current.

In view of the above-mentioned conventional technology, the present invention maintains the constant current period of the primary current constant even if the primary current of the ignition coil jumps.

[Means for solving problems]

a current detection resistor that detects the primary current of the ignition coil; and a constant current control section that inputs a voltage corresponding to the current flowing through the current detection resistor to control the primary current of the ignition coil to a predetermined value. , a sample hold circuit that holds a voltage corresponding to the primary current flowing through the ignition coil when the ignition coil starts being energized; and a time constant that corresponds to the time constant of the ignition coil when the ignition coil starts being energized. The output of the sample and hold circuit is compared with the output of the sample and hold circuit that outputs a signal that is the rising edge of The present invention provides an ignition device for an internal combustion engine having an analog signal switching circuit which inputs the output of the circuit and inputs a set voltage to the constant current control section when the output of the circuit is small.

[Effect]

Even if the primary current of the ignition coil jumps,
Corresponding and comparing with the rise amount of the primary current in the ignition coil when no jump occurs, the jump amount of the primary current is maintained until the jump amount of the primary current, and then the primary current is passed through the ignition coil. Therefore, the constant current period of the primary current is always kept constant.

〔Example〕

The present invention will be described below with reference to embodiments shown in the drawings. As shown in FIG. 3, the signal rotor 100
1, detecting the ignition timing of the ignition coil 180,
An ignition timing control circuit 1000 for controlling is connected. And the rotation angle sensors are 1001 and 1002
1001 is a signal rotor made of ferromagnetic material constructed in the date reviewer in order to detect the reference position of the internal combustion engine. It has a structure with protrusions at certain positions. 10 more
Reference numeral 02 denotes an electromagnetic pick-up, which generates an electric signal that is a reference position for each cylinder of the internal combustion engine by changing the interlinkage magnetic flux with the signal rotor 1001.
1003 is a well-known voltage level comparison type shaping circuit, which shapes the waveform of the signal from the electromagnetic pick-up 1002 and connects it to an interrupt input terminal of a microcomputer (MPU) 1004 that constitutes an arithmetic unit.
Supply to INT.

The microcomputer 1004 is, for example, a 68 series 8-bit microcomputer (6801).
Electromagnetic pick-up 1002 and shaping circuit 1003
The MPU 1004 constitutes an ignition timing control circuit.

Then, the signal waveform shaped by the shaping circuit 1003 is
The MPU 1004 controls the target ignition timing from engine parameters such as engine load size and engine speed, and keeps the ignition coil energized time almost constant even when the engine speed changes, and when the ignition coil is energized. is under control. Since the circuit shown in Figure 3 is conventionally known, detailed explanation will be omitted. (Also, publicly known materials include, for example,
This is shown in Japanese Patent Application Laid-Open No. 57-195867. ) Then, as shown in FIG. 2A, the ignition coil 180
An ignition timing control rectangular wave that rises at the start of energization and then rises at the ignition timing of the ignition coil 180 by keeping the energization time approximately constant is generated.

Further, the rectangular wave shown in FIG. 2A is input to the input terminal 1.

A power supply voltage is applied to the terminal 2.

100 is a monostable circuit, and this monostable circuit 1
00 is composed of a monostable circuit component 101, a resistor 103, and a capacitor 102. The monostable circuit component 101 is, for example, a product name manufactured by Toshiba.
It is equivalent to TC4047BP. In addition, the negative trigger (-TR) of the monostable circuit component 101 has terminal 1.
is connected. Furthermore, the resistor 103, the capacitor 102, and the resistor 103 and the capacitor 102
The connection points with are connected to monostable circuit components 101, respectively. The output (Q) of the monostable circuit component 101 is activated at the falling timing, which is the start of energization to the ignition coil 180 in FIG. 2A, and has a constant pulse width (about 100 μs) as shown in FIG. )
and outputs a high level. Further, the pulse width shown in FIG. 2c is set by a capacitor 102 and a resistor 103.

110 is an integrating circuit. Resistor 111 is connected between terminal 2 and the collector of transistor 113. Further, the resistor 112 is connected between the terminal 1 and the base of the transistor 113.
The emitter of transistor 113 is grounded. Further, one end of the capacitor 114 is connected to the collector of the transistor 113, and the other end is grounded. The time constant set by the resistor 111 and the capacitor 114 is made the same as the time constant set by the inductance and internal resistance of the ignition coil 180 by adjusting the resistor 111. A triangular wave output signal from the collector of the transistor 113 of the integrating circuit 110 is shown in FIG. 2B.

120 is an analog signal switching circuit. 12
1,122 is a resistance. Reference numerals 123 and 124 designate first and second analog switches, respectively, which are equivalent to Toshiba's product name TC4066BP, for example. 12
5 is an inverter, for example, the product name of Toshiba Corporation
It is equivalent to TC4069BP. The input side 123a of the first analog switch 123 is connected to the resistor 121.
and the connection point of the resistor 122. Further, one end of the resistor 121 is connected to the terminal 2, and one end of the resistor 121 is connected to the terminal 2.
One end of 2 is grounded. The input side 124a of the second analog switch 124 is connected to the output of the sample and hold circuit 140. The output side 123b of the first analog switch 123 and the output side 124b of the second analog switch 124 are connected. and the first analog switch 1
The control terminal 123c of 23 is connected to the output side of the comparator 130 via the inverter 125. In addition, the second analog switch 124
A control terminal 124C of is connected to the output side of the comparator 130.

The comparator 130 is, for example, a product name of NEC Corporation.
It is equivalent to upc277c. and comparator 130
The inverting input side of is connected to the collector of the transistor 113 of the integrating circuit 110, and the non-inverting input side is connected to the collector of the transistor 113 of the integrating circuit 110.
Operational amplifier 143 of sample and hold circuit 140
connected to the output of

140 is a sample and hold circuit. 141
is an analog switch, for example, a product equivalent to Toshiba's product name TC4066BP. 142 is a capacitor, and 143 is an operational amplifier that functions as a buffer, such as NEC's product name upc1251c. and the input side 14 of the analog switch 141
1a is connected to the other end of a resistor 150 whose one end is grounded, and the output side 141b is connected to the positive input terminal of the operational amplifier 143. Further, the control terminal 141c is connected to the output of the monostable circuit component 101 of the monostable circuit 100. Furthermore, the other end of the capacitor 142, which has one end grounded, is connected between the positive input terminal of the operational amplifier 143 and the input side 141a of the analog switch 141. Further, the negative input terminal and output side of the operational amplifier 143 are connected.

Due to the potential difference between both ends of the resistor 150, the ignition coil 1
A primary current value of 80 is detected. The resistance value of the resistor 150 is, for example, about 50 mΩ.

160 is a constant current control section. 161,16
2,165 is a resistance. 163, 166, 16
9,170 is a transistor. 164 is a comparator, for example, a product equivalent to NEC's product name upc277c. 168 is a Zener diode, whose Zener voltage is about 340V,
It serves to protect the transistors 169 and 170. The base of the transistor 163 is connected to the terminal 1 via the resistor 161, the collector is connected to the terminal 2 via the resistor 162, and the emitter is grounded. Further, the inverting input side of the comparator 164 is connected to the first and second analog switches 1
The non-inverting input side is connected to the other end of the resistor 150. Further, the output side of the comparator 164 is connected to the transistor 16 via a resistor 165.
It is connected to the base of 6. The collector of transistor 166 is connected between the collector of transistor 163 and resistor 162, and its emitter is grounded. The base of the transistor 169 is connected to the collector of the transistor 166. Further, the collector of the transistor 169 is connected to the collector of the transistor 170, and the emitter is connected to the base of the transistor 170, respectively. The emitter of transistor 170 is connected to resistor 150. moreover,
The anode side of the Zener diode 168 is connected to the base of the transistor 169, and the cathode side of the Zener diode 168 is connected to the collector of the transistor 169. An ignition coil 180 is connected between the terminal 2 and the cathode side of the Zener diode 168.

The ignition coil 180 includes a primary coil 181 and a secondary coil 182 that sends high voltage to the ignition plug 183.
It consists of

Next, the operation of the above configuration will be explained.
FIG. 2A is an input signal to terminal 1, which is an ignition signal that is computationally controlled by the circuit shown in FIG. Second
Figure B shows the output signal of the integrating circuit 110, Figure 2C
is the output signal of the monostable circuit 100, and FIG. 2D is the output signal of the monostable circuit 100.
The output signal of the sample hold circuit 140, FIG. 2E is the output signal of the comparator 130, and FIG. 2F is the output signal of the analog signal switching circuit 120, FIG. 2G
is the output signal of the comparator 164 of the constant current control section 160, and FIG.

While the high level of the ignition signal of FIG. 2A is applied to terminal 1, transistor 163 is turned on via resistor 161. While the transistor 163 is on, the base and emitter of the transistor 169 are short-circuited to cut off power to the ignition coil 180. Next, the low level of the ignition signal is input to the terminal 1, and the transistor 163 is turned off at the rising timing (t ₀ , t ₃ , t ₇ , t ₁₁ ). Then, due to the power supply voltage of terminal 2, resistance 16
2, the transistor 169,1 in the saturation region
Turn on 70. And transistor 170
turns on, the power supply voltage at terminal 2 changes to ignition coil 1.
The primary coil 181 of 80 is energized. and 1
As shown in FIG. 2H, which is the potential difference of the secondary current detection resistor 150, the current in the primary coil 181 increases with the time constant of the inductance and internal resistance of the ignition coil 180 between t ₀ and t ₁ . Further, at the rising timing (t ₂ , t ₆ , t ₁₀ ), which is the start of energization to the ignition coil 180 in FIG. 2A, the transistor 163
turns on, turning off transistors 169 and 170. Then, the primary coil 1 of the ignition coil 180
81, the current flowing from the power supply voltage is cut off, and 2
A high voltage is supplied to the next coil 182, and the spark plug 1
83 to produce an ignition spark.

At the falling t ₀ timing, monostable circuit 1
00, a high level with a constant pulse width as shown in FIG. 2c is output. And during this high level of signal,
The analog switch 141 of the sample hold circuit 140 is turned on. However, since no jump occurred in the primary current of the primary coil 181, no voltage was input to the comparator 143, and no voltage was input to the comparator 143 as shown in FIG.
The output of the sample and hold circuit will be at a low level. The triangular wave shown in FIG. 2B, which is the output of the integrating circuit 110, is input to the minus input side of the comparator 130, and a low level is input to the plus input side, so the output of the comparator 130 is lowered. level. Therefore, the first analog switch 123 of the analog signal switching circuit 120 is turned on via the inverter 125, and the second analog switch 124 is turned off. Then, the power supply voltage is
21 and 122, the divided voltage is used as the output of the analog signal switching circuit 120 in FIG. 2F. Then, the level of this output is inputted to the negative input side of the comparator 164. Further, the voltage of the resistor 150 corresponding to the primary current of the primary coil 181 is input to the positive input side, and since the negative input side is initially larger than the positive input side, the output of the comparator 164 is is at a low level as shown in FIG. 2G. Therefore, transistor 166 is off and transistor 17 is off.
0 conduction causes a primary current to flow through the primary coil 181 from the power supply voltage. Then, as shown in FIG. 2H, the voltage across the resistor 150 gradually increases. Furthermore, when this voltage increases at time t ₁ and the positive input side of comparator 164 becomes greater than the negative input side, the output of comparator 164 goes high, causing transistor 166 to operate in the unsaturated region. Due to this conduction of transistor 166, transistor 170 operates in an unsaturated region, and transistor 1
The current flowing through 70 is made constant. And t ₁ ~ _{t 2}
During this period, constant current control is performed so that the positive and negative input voltages of the comparator 164 are approximately equal, and the value of the primary current flowing through the primary coil 181 of the ignition coil 180 is held at a predetermined value for a predetermined time. ing.

In order to increase the primary current of the ignition coil, increasing the closing angle will conversely shorten the time during which the primary current does not flow, so energization will start at the next timing before the arc discharge ends at the ignition plug. Therefore, primary current begins to flow. Then, the energy remaining on the secondary side of the ignition coil reduces the inductance of the primary coil, so the primary coil appears to only have internal resistance, and as soon as the current is turned on, a current suddenly flows, causing the primary current to jump. This is called a jump in the primary current.

Next, the timing at _t3 when the primary current of the primary coil 181 jumps will be explained.
Similar to the timing t ₀ described above, the monostable circuit 100 outputs a high level at timing t ₃ , and during this high level, the analog switch 141 of the sample and hold circuit 140 is turned on. At this time, Fig. 2H shows 1 due to the jump in the primary current.
The next current signal level has appeared, and this signal level is input to the plus input side of the operational amplifier 143.
Further, the capacitor 142 is charged, and while the analog switch 141 is off, the output of the operational amplifier 143 is held for a certain period of time due to the charge in the capacitor 142. In the output signal of this operational amplifier 143, a voltage value corresponding to the jump amount of the primary current, _V1, appears.

Initially, the signal is input to the negative input side of the comparator 130, and the primary coil 1 of the ignition coil 180
Compared to the triangular wave signal of the output of the integrating circuit 110, which has the same time constant as the primary current flowing through the comparator 130, the _V1 voltage value of FIG. The output is high level. Then, the first analog switch 123
is turned off via the inverter 125, and the second analog switch 124 is turned on. Therefore, the analog signal switching circuit 120 outputs the output signal V ₁ of the sample and hold circuit 140 as it is.
Therefore, the output of the comparator 164 becomes high level,
Transistor 166 is operated in the unsaturated region.
This conduction of transistor 166 causes transistor 170 to operate in an unsaturated region, thereby making the current flowing between the collector and emitter of transistor 170 constant. While the triangular wave output of the integrating circuit 110 is smaller than the output of the sample and hold circuit 140, the current value is maintained at a value equal to the jump amount of the primary current.

Next, at timing _t4 , the integrating circuit 110
The triangular wave output signal is sent to the sample hold circuit 1.
₄₀ , the output of the comparator 130 goes low. Then, the first analog switch 123 is turned on, the second analog switch 124 is turned off, and the analog signal switching circuit 120 outputs the divided voltage of the power supply voltage by the resistors 121 and 122. This divided voltage is then input to the negative input side of the comparator 164.

In response to this, the negative input side of the comparator 164 becomes larger than the positive input side, and the comparator 164
output to a low level. Therefore, transistor 166 is turned off and transistor 170 is turned on in the saturation region. Then, constant current control section 160
is the primary current of the primary coil 181, and the resistance 150
The voltage is increased at a certain time constant until t ₅ when the voltage becomes larger than the output of the analog signal switching circuit 120. Then, between t ₅ and ignition timing t ₆ , the primary current is applied for a predetermined period of time in the same way as between t ₁ and _{t 2} described above.
It can be controlled to a predetermined value.

Note that even between _t7 and _t10 , as described above, the primary current can be controlled to be a constant current of a predetermined value for a predetermined period of time depending on the jump amount of the primary current.

Even if the power supply voltage changes here, there is no problem because the power supply voltage signal is input to both the integrating circuit 110 and the analog signal switching circuit 120. Also, coil 18
Although there are individual differences in the time constant due to zero inductance and internal resistance, it can be adapted by adjusting the time constant with the resistor 111 and the capacitor 114.
Next, the primary current value can be adjusted by adjusting the divided voltage values of the resistors 121 and 122.

FIG. 4 shows a comparison between the prior art and the present invention. Here, the solid line is a conventional waveform, and the dotted line is a waveform according to the present invention. 4a is a waveform diagram of the primary current of the primary coil 181, b is a waveform diagram of the internal resistance of the transistor 170, and c is a diagram of the waveform of the internal resistance of the transistor 1.
70 is a waveform diagram of the power consumption, d is a waveform diagram of the internal resistance of the coil 180, and e is a waveform diagram of the power consumption of the coil 180. Therefore, as for the power consumption of the transistor 170 and the power consumption of the coil 180, as shown in FIGS. 4c and 4e, the shaded portions can be the reduced power consumption.

Further, the time constant of the output signal of the integrating circuit 110,
The time constant of the primary current of the primary coil 181 of the ignition coil 180 is the same as that of the primary current of the primary coil 181 of the ignition coil 180, but due to the output of the sample and hold circuit 140, the time constant of the output signal of the integrating circuit 110 is set to be the same as that of the primary current of the primary coil 181. , may be set according to the time constant of the primary current of the primary coil 181 so as to perform constant current control of a predetermined value.

〔Effect of the invention〕

As described above, the present invention includes a constant current control section that controls the primary current of the ignition coil to a predetermined value, and a rise of a time constant corresponding to the time constant of the ignition coil at the start of energization to the ignition coil. Compare the output of the integration circuit that outputs the signal and the sample and hold circuit that holds the voltage according to the primary current flowing through the ignition coil with the output of the integration circuit, and if the output of the sample and hold circuit is large, The output of the sample and hold circuit is input to the constant current control section, and when the output voltage is small, the set voltage is input to the constant current control section. Even if a jump occurs, this jump is detected at the timing of energization to the ignition coil, and even if a jump occurs in the ignition coil's primary current, the ignition coil's primary current when no jump occurs Corresponding to and comparing with the rise amount, the primary current jump amount is maintained until the primary current jump amount, and then the primary current is sent to the ignition coil, so the primary current is always kept at the predetermined level. The constant current can be controlled to a predetermined value for a certain period of time, and the constant current control has the excellent effect of reducing the power consumption of the ignition coil and the transistor for driving the ignition coil.

[Brief explanation of drawings]

Fig. 1 is an electric circuit diagram showing an embodiment of the main part of the present invention, Fig. 2 is a timing chart for explaining the operation of the above embodiment, and Fig. 3 is a terminal 1 of the above embodiment.
FIG. 4 is a waveform diagram showing a comparison between the above embodiment and a conventional example, FIG. 5 is a schematic diagram showing an ignition coil energization control system to which the conventional application is applied, and FIG. 6 is the above-mentioned Conventional control flow diagram,
7 and 8 are waveform diagrams for explaining operations in the control flow of FIG. 6. 110... Integrating circuit, 120... Analog signal switching circuit, 140... Sample hold circuit, 150
... Current detection resistor, 160... Constant current control section, 18
0...Ignition coil.

Claims (1)

[Claims] 1. A current detection resistor that detects the primary current of the ignition coil, and a constant current control unit that inputs a voltage corresponding to the current flowing through the current detection resistor and controls the primary current of the ignition coil to a predetermined value. and 1 flowing through the ignition coil at the start of energization to the ignition coil.
a sample and hold circuit that holds a voltage according to the next current; an integration circuit that outputs a signal that is the rise of a time constant corresponding to the time constant of the ignition coil when electricity starts flowing to the ignition coil; and the sample and hold circuit. The output of the sample and hold circuit is compared with the output of the integration circuit, and if the output of the sample and hold circuit is large, the output of the sample and hold circuit is input to the constant current control section, and if the output of the sample and hold circuit is small, the set voltage is An ignition device for an internal combustion engine having an analog signal switching circuit input to a constant current control section.