JPS5851155B2 - Electronic ignition control device for internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic ignition control system for an internal combustion engine that digitally performs advance angle control and energization angle control, and is particularly intended to improve ignition performance during engine acceleration and deceleration.

In an electronic advance angle control device for an internal combustion engine, it is important to know the current position of a rotationally driven crankshaft with respect to a reference point (top dead center), and various proposals have been made in the past.

The most common method of detecting this crank angle is to count them using multiple electromagnetic or optical detection means installed at equal intervals on a rotating disk that rotates in synchronization with the crankshaft. This is a method of detecting the current crank angle by detecting the crankshaft angle.However, if this method is to detect the crankshaft angle with high precision, a large number of the above-mentioned detection means are required, which is very disadvantageous in terms of manufacturing and economics. be.

In order to prevent this, the above-mentioned detection means can be used in several pieces, for example, two pieces, and the period can be measured based on the detection pulses output every 1/2 revolution, and the intermediate crank angle between these pieces can be calculated with electrical means to achieve high accuracy. resolution can be obtained.

However, since this method predicts the next cycle based on the previous cycle, it is effective when the engine speed is constant, but when the engine speed fluctuates, it cannot directly account for this effect. Not only will the ignition timing accuracy deteriorate, but also the ignition timing will be extremely delayed when the speed increases rapidly, such as during no-load racing, resulting in a misfire.Furthermore, when there is a sudden deceleration, the ignition timing will be abnormally advanced and the engine will need to be re-engineered. It will be a huge burden.

The present invention has been made in view of the above points, and includes means for detecting the reference point (top dead center) of the crankshaft and means for detecting the maximum forward angle advance position. This aims to reduce the advance angle error due to changes in the angle, prevent abnormal advance and retardation caused by rapid changes, and at the same time control the energization angle of the ignition coil.

An embodiment of the present invention will be described below.

FIG. 1 is a basic configuration diagram showing an embodiment of the present invention, FIG. 2 is a timing chart of each part in FIG. 1 when the engine speed is constant, FIG. 3 is a timing chart during deceleration, and FIG. Figure 4 shows a timing chart during acceleration.

5 and 6 show the correlation between calculation timing and output.

In Fig. 1, 1 is a detector for detecting that the crankshaft has reached the ignition reference position (top dead center), and is usually installed in a power distribution device that rotates with 1l2 revolutions of the crankshaft.
Each cylinder of the engine produces power each time it reaches top dead center.

2 is a similarly provided crankshaft position detector;
It is provided at a position away from the detector 1 in the rotational direction by the maximum advance angle.

For example, if the maximum advance angle is 45 degrees at the crankshaft, the detector 2 detects that each cylinder of the engine is at 45 degrees before top dead center.
Generates an output every time the position is reached.

A reference oscillator 3 sends a reference clock to each counter described later.

4 is a counter that measures the period of the output of the detector 2, and 5 is a register that stores the count value of the counter 4.

With the above combination, each time the detector 2 generates an output, the counter 4 completes counting of the reference clock of the oscillator 30, transfers the data to the register 5, resets the data, and then starts counting again.

At the same time, the output of the detector 2 is sent to the arithmetic circuit 10.

6 is a preset type subtraction counter for ignition timing control, which presets the data in register 7 every time the output of detector 2 is generated and starts subtraction operation based on the frequency of reference oscillator 30, and when the counter value is When it becomes zero, a carry output is sent.

8 is a subtraction counter for controlling the energization timing, and like counter 6, every time a signal is received from the load terminal, it presets the set value of register 9 and starts subtraction, and when it reaches zero, it sends out a carry output. .

, 10 is an arithmetic circuit which starts operating every time the detector 2 generates an output, receives data from the register 5, and takes in the period between the upper hole points of the crankshaft.

Based on this cycle value and predetermined advance angle data, the data to be set in the counter 6 is calculated and sent to the register 7, and the ignition coil is energized based on this data and the predetermined ignition coil energization time. Send start time data to register 9.

Reference numeral 11 is an OR gate, which synthesizes the logical sum of the counter 6 and the detector 1.

12 is an inverter which inverts the output of the OR gate 11 and sends it to the T terminal of the D type flip-flop 13.

Since the function of the D-type flip-frog 13 is common, its explanation will be omitted here.

14 is an AND gate, and by taking the AND logic of the inverted output Q of the flip-flop 130 and the OR gate 11, only the output that reaches the first output after the flip-flop 13 is reset is selected from among the output of the counter 6 and the output of the detector 1. Control the machine that allows it to pass.

15 is an OR gate which takes the logical sum of the outputs of the counter 8 and the detector 2 and supplies it to the flip-flop 16.

As a result, the flip-flop 16 is set by the signal that arrives again after the above-mentioned two-manpower reset, turning on the transistor 18 through the power amplification section 17, and causing current to flow through the ignition coil 19.

When a reset signal is input to the flip-flop 16, the Q output of the flip-flop 16 is inverted and the transistor 18 becomes O.
FF, the primary current of the ignition coil 190 is cut off, a high voltage is induced on the secondary side, and ignition is performed.

20 is a battery. 2 to 4 are timing charts of each part in FIG. 1, and A to 1 in the figures indicate waveforms of portions A to 10 shown in FIG. 1.

The operation of the apparatus constructed as described above during constant rotation will be explained with reference to FIGS. 1 and 2.

Detector 1 detects the top dead center position of the crankshaft, and detector 2 detects the top dead center position of the crankshaft.
The advanced position is detected respectively, and if the engine is a 4-cycle 4-cylinder engine, each detector 1°2 is 45°.
Separately, it generates an output every 1800 (every 1l2 revolutions).

The period measurement counter 4 measures the output generation period of the detector 2, which is t in FIG. 2A.

This is for counting the clock of the development oscillator 3 from the time up to 11 hours.

The state of the counter 4 during counting is shown at time t in FIG. 2C.

T from time t1 to time t1. If Cs1l is the final count value N of counter 4.

is expressed by the following formula, where the reference frequency is fo (Hz).

In the arithmetic circuit 10, this count value N is assumed to continue the cycle next time.

The value N8 to be set in the ignition timing counter 6 is calculated based on the advance angle value θ0, which has been determined in advance under different conditions, corresponding to 1800.

Since the counter 6 starts subtracting when the output from the detector 2 is generated, the arithmetic circuit 10 performs the calculation shown by the following equation, taking this into account.

If the above N8 value is calculated and stored in the register 7, the counter 6 will preset the above value and start subtraction every time the detector 2 generates an output.

The reference clock for subtraction is f.

(Hz), the time T8' from the generation of the output of the detector 2 until the generation of the carry output of the counter 6 is TS It is clear that the ignition signal is output at time t2 corresponding to the advance angle θ.

Gate 11. Inverter 12, flip-flop 13,
As shown in FIG. 2 above, the AND gate 14 constitutes an ignition timing discrimination circuit that selects the signal that arrives earlier between the odor signal and the (B) signal, and in the example shown in FIG. At time t2 and time t3, the (5) signal is sent to the flip-flop 16 and counter 8 as the (G) signal since the D signal is earlier.

The flip-flop 16 thereby cuts off the current flowing through the ignition coil 19 to ignite.

In the one-wave S circuit 10, the ignition coil 190
The energization time TD(s) is set in advance, and the setting value ND to be set in the counter 8 so as to match this value is calculated based on the following equation.

The numerical value n corresponding to the energization time T D (Sl) is estimated in advance, and the result is sent to the register 9 after calculating the above formula.

The counter 8 receives the ignition signal G at time t2, presets the setting ND of the register 9 in the counter, and starts subtraction.

Here, the time T2-4 required from time t2 to time t4 when the carry output of the counter 8 is generated is as follows.On the other hand, the energization time T4-6 is expressed as 'r4-6='ro 'r2-4, and the above equation is When substituted into the Kono equation, the energization time is controlled to the set time TD.

Note that when the engine speed becomes high and the condition of To≦TD is reached, the reset period of the flip-flop 16 disappears and ignition is no longer performed. Therefore, the equation (5) NDo: ND value that satisfies a predetermined value increase equation. In this case, it is necessary to forcibly secure a predetermined reset time as ND-NDo. Usually, this value is set to a value corresponding to about 1 ms, taking into account the duration of the secondary spark current, etc.

As described above, in this embodiment, the ignition timing setting counter 60 does not start the subtraction from the previous top dead center position (for example, time t3), but from the top dead center position by 45 seconds.
The process starts from an advanced position (for example, time t5), and these situations are shown by straight lines in FIG. 2, 21 and 22.

This is effective in reducing ignition timing errors when the engine speed fluctuates.

In other words, since the ignition timing set value is controlled based on the previous cycle with the expectation that the next cycle will be the same, if the cycle changes after the cycle is measured, this effect will increase as the distance from top dead center increases.

In FIG. 2, time t. If the period is measured between ~t1 and the rotation speed changes thereafter, as shown by line 21, if subtraction is started from time t3, the value at time t5 will have a larger difference from the actual current angle than at time t4. It is what it is.

In particular, although the time near the end of one cycle is controlled, such as advance angle control, the cumulative error from time t3 to time t5 is quite large in Nonia.

On the other hand, in this embodiment, the counter starts subtracting from time t5, which is the maximum advance angle, and this time t5 is precisely the 45° advance angle position, and if subtraction is started from this position, the angle with the actual angle is It is clear that the error is reduced.

Furthermore, as will be described later, this method has the effect of preventing abnormal advance angle even in response to periodic fluctuations during sudden deceleration.

If the engine load suddenly increases when the engine is running at low speed, the cycle of detector 1 and 2 outputs will change by 2.
More than twice as many cases occur.

In this case, if the lead angle value is set to, for example, 30° based on the previous cycle, then if subtraction is performed using the method shown in Figure 2, the lead angle value will be approximately 105° since the current cycle will be doubled. This causes knocking due to abnormal advance angle, which adversely affects the engine.

On the other hand, in this embodiment, the angle is about 37°, which is a much smaller error than the above.

Next, the operation of each part when the engine rotation suddenly decelerates is explained in the third section.
This will be explained in the figure.

The figure shows a case where the engine speed has decreased by 20% from the previous value.

The output shown by the broken line in Figure 2 A and B is at time 15 when the speed is constant.
．． 16, which is generated from the detectors 1 and 2 at time t'6. This indicates that the position has moved to t'6.

The advance angle error in this case does not become a large value because the output generation time t'5 of the detector 2 also moves as the period changes as described above.

The energization time to the ignition coil is indicated by 1 and H
The period is energized.

As is clear from this, since the energization start timing counter 8 starts subtracting from time t2, which is the previous ignition time, the energization period is longer.

Although this is a slight loss in terms of energy, it is on the safe side from the point of view of ignition control, and the energy necessary for ignition can be sufficiently secured.

FIG. 4 shows the operation of ignition timing control and energization timing control when the engine speed increases rapidly, such as during no-load racing.

The figure shows a case where the engine speed suddenly increases after 13 hours have elapsed, and the broken line in the figure shows the operation when the engine speed has elapsed at the same period as in the conventional case.

Regarding ignition control, the output of detector 2 may be 1/
, even though the subtraction by the counter 60 started from time 115, the time t'7 of the output generation from the detector 1 is shorter than the carry output generation time t6 of the counter 6.
Since the signal (B) from the detector 1 reaches the OR gate 11 in FIG. 1 earlier, the flip-flop 16 is reset and ignition is performed.

This is because time t'7 (corresponding to the top dead center of the crankshaft) has advanced, and is intended to prevent the ignition timing from being retarded from the top dead center.

Next, regarding energization control, since the output time 115 of the detector 2 is earlier than the output generation time t4 of the energization start timing counter 8, the flip-flop 16 is turned on at time t'5 via the OR gate 15 in FIG. becomes.

This is very effective in preventing a decrease in ignition energy due to a decrease in energization time.

In such a rapid acceleration state, abnormal retardation can be prevented and sufficient ignition energy can be secured.

Here, the energization time TD is the difference in output generation time between detector 2 and detector 1, which corresponds to 45 degrees on the crankshaft, and is equivalent to 3.75771 S at an engine speed of 2000 rpm.This value is the difference between the output generation time of detector 2 and detector 1. This is a reasonably satisfactory value for the time for energizing, and it is possible to secure ignition energy.

In the region where the engine rotation speed is 2000 rpm or more, the periodic fluctuation is not large due to the inertia of the engine, etc., and as explained above, it is impossible for the energization time to correspond to the time difference between detector 2 and detector 10. Sufficient ignition energy can be secured.

In the above explanation, the arithmetic circuit 100 control method (Kyu (5)
, we will perform the calculations shown in equation (9), but as mentioned above, these equations are for controlling the previous cycle and the current cycle as being the same, and if there is a cycle change due to rotational fluctuation, This affects the advance angle and energization timing.

Therefore, in order to prevent this, if the rate of change in the cycle is detected and the cycle for the current calculation is corrected, it becomes possible to control with very high precision even during acceleration and deceleration.

In other words, if the current cycle is TN, the previous cycle is TN-1,
If TN-2 is the cycle before the previous one, then if TN-1≧TN-2 (decelerating), then TN=TNyo+(TN-1-TN-2)=2TN-+
If TN i'rN-t <'rN-2 (accelerating), then TN=TN-t (TN-2TN-t)=2TN-
(If it becomes TN-2 and always calculates TN-2TN-1-TN-2 to set the cycle for the current ignition energization timing, the control accuracy during constant acceleration and constant deceleration will be 2 after transitioning to acceleration/deceleration.) It becomes very accurate from the first cycle onwards.

In addition, the calculation circuit 10 is used as the setting value of the ignition timing counter.
It is assumed that equation (2) is calculated, but if equation (2) is transformed and the value expressed as (45-θ)/180 is used instead of using the value of θ, the calculation for determining the setting value is possible. As such, it is sufficient to perform the multiplication only once.

Therefore, as for the operation of the arithmetic circuit 10, it is only necessary to perform multiplication once (for ignition) and subtraction once (for energization) each time the output of the detector 2 is generated.

Furthermore, if high accuracy is required during acceleration/deceleration, it is sufficient to perform multiplication (square) and subtraction once each.

Although not explained in the embodiments of the present invention, the power amplification section 17 is generally used for efficient use of ignition energy, miniaturization of the power transistor 18, miniaturization of the ignition coil 19, and reduction of resistance inserted in series with the ignition coil. For the sake of omission, etc., a constant current control circuit is built in, and as a result, as the current supply time becomes longer, the amount of heat generated by the power amplifying section increases, and the transistor 18 must be made larger.

In this embodiment, the OR gate 15 shown in FIG. 1 controls the time at which the energization start time is the latest to occur when the output from the detector 2 is generated, so that the engine rotation speed is approximately 900 r.
When pmJJ is below, the energization time becomes longer than the normal energization time, and the power amplification section generates heat because the power is applied during the output generation time interval of the detectors 1 and 2.

This can be easily prevented by configuring a logic that prohibits the signal (4) of the OR gate 15 (output of the detector 2) in FIG. It is something that can be done.

At this time, if the vehicle changes from an idle state to an acceleration state, the idle detection switch is immediately turned OFF.
The signal from the detector 2 acts effectively and ignition occurs during acceleration without misfire.

5 and 6 show the correlation between the calculation timing of the calculation circuit 10 and its output timing.
The figure shows the case of the two detector system shown in this embodiment.

In FIG. 5, calculations for energization control and ignition timing control are performed each time the crankshaft reaches TDC (Top Dead Center), as shown in (b), at time t.

The period T between and time t1. The result calculated based on -1 is reflected in θ3 in the figure regarding the ignition timing.

This is because the subtraction for controlling the θ2 lead angle value starts from time t1, making it impossible to reflect the result calculated at time t1 in the θ2 lead angle value.

On the other hand, the energization start timing control is reflected in the ND period and controls the D3 period.

This is because it is highly conceivable that the energization for the D2 period has already started at time t1 (during high speed rotation).

As explained above, in this method, the result of measuring the period is reflected in the energized ignition timing with a delay of two periods.
Compared to a one-cycle delay, the accuracy error increases when there is a rotational speed fluctuation.

On the other hand, FIG. 6 enables one-period delay control using the method of the present invention.

T in the figure. The result of time 1/1 calculation based on the '-1' cycle is as follows regarding the energization timing control.

In other words, since the calculation time is very short, it is completed by time t8 (ignition timing) shown in Figure 6g, and the energization timing counter 8 can start subtracting from time ts, resulting in a delay of one cycle. The time width of the D2 period can be controlled.

Since the ignition timing set value obtained at the same time is set in the ignition timing control counter 6 at time t'2 and starts subtraction, θ
This can be reflected in the binary angle value control with a one-cycle delay.

As is clear from the above explanation, the present invention is configured to detect the crankshaft position by detecting two reference positions near the top dead center and the maximum advance point, and then calculates the ignition energization timing at the maximum advance point. Since the ignition counter starts operating from the maximum advance position, it is possible to minimize the error in the ignition advance timing even with periodic changes due to acceleration and deceleration of engine rotation. Abnormal advance angle during rapid deceleration can also be limited by the maximum advance angle position, and at the same time, the value for ignition energization is updated with a one-cycle delay, improving accuracy.

Further, since an ignition timing determination circuit is provided so that ignition is performed at least by top dead center, it is possible to prevent abnormal retarded ignition during rapid acceleration.

Furthermore, in the energization start timing control, the energization is started by the early generation signal of the counter output that starts operation from the previous ignition and the maximum advance point position detection signal, so the energization starts from at least the maximum advance angle position and accelerates rapidly. It is possible to secure ignition energy at the same time.

As described above, the method of the present invention is simple; by using two rank shaft rotation angle position detection sensors and by implementing a simple logical configuration, the ignition timing is always set between the maximum advance position and the earth position, and the ignition energy is The effects of the present invention are very significant, such as being able to always ensure sufficient ignition and sufficient ignition even in response to rapid changes in engine speed.

[Brief explanation of drawings]

Fig. 1 is a basic configuration diagram showing an embodiment of the present invention, Figs. 2 to 4 are timing charts of various parts for explaining the operation of Fig. 1, and Figs. 5 and 6 are correlations between calculation results and calculations. It is Homa. In the figure, 1 and 2 are detectors, 3 is a reference oscillator, 4 is a period measurement counter, 6 is a counter for ignition timing, 8 is a counter for energization timing 5, 7 and 9 are registers, 10 is an arithmetic circuit, 1
1.15 is an OR gate, 12 is an inverter, 13 is a D type flip-flop, 14 is an AND gate, 16 is a flip-flop, 17' is a power amplifier, 18 is a power transistor, 19 is an ignition coil, and 20 is a battery. .

Claims (1)

[Claims] 1. A first detector that detects a first reference rotational angle position near the top dead center of the internal combustion engine, a second detector that detects a second reference rotational angle position near the maximum position of the ignition advance timing, a period measuring counter that measures the output period of the second detector to detect the engine rotation speed; and a period measuring counter that detects the engine rotation speed by measuring the output period of the second detector, and adjusting the ignition timing and the ignition coil each time the output of the second detector is generated based on the count value of the period measuring counter. an arithmetic circuit that calculates the energization start timing; an ignition timing output value determined by the arithmetic circuit is preset every time the output of the second detector is generated, and counting is started; and after a time corresponding to the preset value has elapsed, ignition timing is started; A counter for counting ignition timing that outputs a signal, distinguishes between the output of the counter for counting ignition timing and the above-mentioned first detector output, and determines the signal that arrives first after the generation of the above-mentioned second detector output as the ignition timing. An ignition timing discrimination circuit that serves as a signal, presets the energization start timing output value determined by the arithmetic circuit and starts counting every time the output of the ignition timing discrimination circuit occurs, and determines the energization timing after a time corresponding to the preset value has elapsed. A counter for counting the energization timing that outputs a signal, distinguishes between the output of the counter for counting the energization timing and the output of the second detector, and determines the first signal that arrives after the output of the ignition timing determination circuit is generated as the energization start time, and An electronic ignition control device for an internal combustion engine, which is comprised of a circuit device that controls energization time to an ignition coil with the generation of an ignition timing determination circuit output as the ignition timing.