JPH0694859B2 - Ignition timing control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ignition timing control device for a low-voltage power distribution system of an engine.

[Conventional technology]

A conventional ignition timing control device is provided with a high voltage power distribution system for applying a high voltage to an ignition plug of each cylinder through one rotor, and an ignition coil for each cylinder, and a drive signal is distributed to each ignition plug. There is a low voltage distribution system. The low-voltage power distribution system is used for the purpose of improving engine performance by improving ignition energy, reducing noise sources by eliminating high-voltage power distribution, and improving commercial image.

FIG. 1 shows an ignition timing control device for a low-voltage power distribution system of an engine, where 1 is a 4-cylinder engine, 2 is a # 1- # 4 spark plug provided for each cylinder of the engine 1, and 3 is an engine 1.
Intake pipe, 4 is a Karman vortex airflow sensor (abbreviated as AFS) provided at the inlet of the intake pipe 3, 5 is an air cleaner further provided on the inlet side of the AFS 4, and 6 is a slot valve provided at the intake pipe 4. , 7 are crank angle sensors for detecting the number of revolutions of the engine 1, which are crank angle reference signals (SGT
Abbreviated. ) And a cylinder identification signal (abbreviated as SGC). 8 is an ignition coil for applying a high voltage to the # 1 and # 4 spark plugs 2, and 9 is an # 2 and # 3 spark plug 2
Ignition coil to apply high voltage to, 10 is AFS4 output, SG
The ignition control unit receives T and SGC and distributes a drive signal to the ignition coils 8 and 9. 11 to 13 are interfaces, 14,15
Are first and second counters, 16 to 18 are first to third timers, 19 is an A / D converter for A / D converting the power supply V _B , and 20 is ROM, RAM
CPU with, 21 is a not circuit, 22 and 23 are AND circuits, 2
4,25 are drivers, and 26,27 are transistors.

In the above structure, the ignition control unit 10 outputs the AFS4, SGT, S
When a GC is input, drive signals are alternately distributed to the ignition coils 8 and 9. The ignition coils 8 and 9 apply a high voltage to each of the two ignition plugs 2, but if one cylinder is in the compression stroke, the other cylinder is in the exhaust stroke and is ignited one by one.

[Problems to be solved by the invention]

However, the engine 1 has various noises, and if these noises are superimposed on the SGC, this noise cannot be removed by the filter circuit depending on the size, and the SGC may be misread. Further, an abnormality may occur in the SGC due to poor contact of the connector or defective crank angle sensor 7. In these cases, the drive signals for the ignition coils 8 and 9 could not be normally distributed, and problems such as running failure and engine destruction due to erroneous ignition occurred.

FIG. 2 (A) shows the normal state of SGC. In this case, SGC is as shown in FIG. (A) and SGT is as shown in (b). The output of the third timer 18 is as shown in FIG. The output of the output port P ₆ of the CPU 20 is H when SGC at the rising edge of SGT is H and L when SGC is L, and therefore is as shown in FIG. This causes driver 25 to occur #
The drive signal for the 1 / # 4 ignition coil 8 is as shown in (e), and the drive signal for the # 2 / # 3 ignition coil 9 generated by the driver 24 is as shown in (f). The output pulse of the timer 18 having the energization time width of 8, 9 is distributed alternately.

However, for example, as shown in FIG.
When noise is superimposed on the SGC, the output of P ₆ becomes as shown in FIG. (D), and each drive signal becomes as shown in (e) and (f), resulting in erroneous distribution.

The present invention has been made to solve the above problems, and an object of the present invention is to prevent erroneous distribution of a drive signal due to noise or SGC abnormality, and prevent the engine from running or being destroyed. .

[Means for solving problems]

The ignition timing control device according to the present invention distributes the drive signal to each ignition coil based on the activation identification signal, and predicts the ignition coil to be distributed this time from the previous distribution, depending on the cylinder identification signal and the prediction. In the case of a difference, the predicting ignition coil is provided with a distribution means for distributing the drive signal.

[Work]

The distribution means according to the present invention predicts the ignition coil to be distributed this time, and when the ignition coil does not match the ignition coil based on the cylinder identification signal, distributes the drive signal to the predicted ignition coil.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. The schematic configuration of the ignition timing control device according to this embodiment is similar to that shown in FIG.

Next, the operation of the above apparatus will be described with reference to the flow charts of FIGS. FIG. 5 (A) shows the main routine, in which initialization is performed in step 101, and step 1
In 02, the battery voltage V _B is A / D converted. At step 103, the output of AFS4 and the cycle T of SGT obtained by the counters 14 and 15
Calculate the intake air amount A / N (abbreviated as AN) per intake air of the engine from _AFS , T _SGT . Similarly, in step 104, the engine speed Ne is calculated from T _SGT . At step 105, ignition timing data θ _A is obtained from the map shown in FIG. 6 (A) stored in the ROM, and similarly at step 106, energization time data T _DWEL is _obtained from the map shown in FIG. 6 (B).

FIG. 5B shows an interrupt processing routine of the pulse period T _AFS of AFS4, in which T _AFS is read in step 201 and the first counter 14 is reset in step 202.

FIG. 5 (C) shows the interrupt processing after the SGT rises,
At step 301, the SGT cycle T _SGT is read, and at step 302, the second counter 15 is reset. In step 303 Calculate T _D = T _A −T _DWEL . T _A is S as shown in FIG.
Time from the start of GT to the end of energization, T _D is the second
This is the output pulse width of the timer 17 of. That is, the second timer
17 goes from L to H at the rising of SGT, and goes from H to L after _TD time. At the time when this becomes L, the timer 18 becomes H and the energization of the ignition coils 8 and 9 is started. Step 304
Then set T _D to timer 17, step 305 sets timer 1
_Set T _DWEL to 8. In step 306, the timer 17 is triggered to activate the ignition operation, and in step 307, the data of the lowest bit of the distribution register is inverted in order to predict the current distribution from the previous distribution of the distribution register in the CPU 20.

In step 308, the SGC level is read, and in step 309, it is determined whether or not the lowest bit of the distribution register is the same as the SGC level.
Set the GC level to the lowest bit in the register and update. At step 311, the judgment counter (forecast
SGC, that is, a counter for determining how many times the lowest bit of the distribution register and the actual SGC do not match has been set to n. In step 312, it is determined whether the least significant bit of the distribution register is 1 or 0. When it is 1, H is output to P ₆ in step 313, and when it is 0, L is output to P ₆ . If the determinations in step 309 are not the same, in step 315 the determination counter is decremented by 1 to determine whether it is 0 or not. If it is not 0, the process proceeds to step 312 and subsequent steps, according to the lowest bit of the distribution register. Find the output of P ₆ . 0
In the case of, that is, when the disagreement continues for a predetermined number of times, noise does not occur continuously, so it is judged that the information of the predicted distribution has gone wrong for some reason, the lowest bit is updated by the actual SGC, and the actual SGC is used. Distribute.

As described above, in the above embodiment, the SGC level is predicted in order to predict the current distribution from the previous distribution, and when the predicted SGC level and the actual SGC level match, the distribution of the ignition coil drive signal is performed by the actual SGC level. If they do not match, distribution is performed at the predicted SGC level, and if they do not match a predetermined number of times consecutively, distribution is performed at the actual SGC level. Therefore, even if an abnormality occurs in the SGC due to noise, the drive signal can be correctly distributed, and even if the prediction information is incorrect, it can be dealt with.

The operation waveform of each part of the SGC in the normal state is the same as that in FIG. 2 (A), and FIG. 3 shows the case where noise is superimposed on the SGC. Thus, even if noise is superimposed on SGC, the output of P ₆ becomes normal, and normal distribution can be performed.

It should be noted that, in the above-mentioned embodiment, if the measures against the deviation of the prediction information are not taken, the steps 311 and 315 are unnecessary.
The present invention can also be applied to the case where the SGC is abnormal due to a cause other than noise. Further, the present invention can be implemented by coding the distribution register even when four ignition coils are provided. For example, 0 is set each time SGC of the cylinder # 1 occurs, +1 is added each time SGT occurs thereafter, 0 is set each time the register contents become 4, and cylinders # 1 to # 4 are set to 0 respectively. It should be coded as 3. Further, in the above embodiment, one timer 18 for generating the coil drive signal is provided and its output is distributed. However, an independent timer is provided for each coil drive signal, and the trigger signal for activating this timer is stored in the distribution register. You may distribute according to the content. In this case, a coil drive signal with a closed circuit rate of 100% or more can be achieved.

〔The invention's effect〕

As described above, according to the present invention, even if an abnormality occurs in the cylinder identification signal due to noise or the like generated from each part of the engine,
The current distribution is predicted from the previous distribution, and if the predicted ignition coil and the ignition coil based on the cylinder identification signal are different, the drive signal is distributed to the predicted ignition coil. It is possible to prevent destruction due to ignition and improve the ignition function.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an ignition timing control device according to the related art and the present invention, and FIGS. 2 (A) and 2 (B) are SGC of the conventional device, respectively.
Operation waveform diagram of each part under normal condition and noise superposition, FIG. 3 is an operation waveform diagram of each part during SGC noise superposition of the device of the present invention
The figure is an enlarged view of the operation waveform diagram of each part, and FIGS. 5 (A) to 5 (C) are flow charts of the device of the present invention, and FIGS. 6 (A) and 6 (B).
Is an engine characteristic diagram. 1 ... Engine, 2 ... Ignition plug, 4 ... Air flow sensor, 7 ... Crank angle sensor, 8,9 ... Ignition coil, 1
0 …… Ignition control unit.

Claims (2)

[Claims] 1. A load detecting means for detecting a load of an engine,
Corresponding to a cylinder, a rotation speed detecting means for detecting the rotation speed of the engine, a cylinder identification signal generating means for generating a cylinder identification signal, a calculating means for calculating an optimum ignition timing for the engine from outputs of the load detecting means and the rotation speed detecting means Ignition provided with drive signal generating means for generating a drive signal corresponding to the ignition timing for each ignition coil provided in the same manner, and distribution means for sequentially distributing the drive signal to each ignition coil based on the cylinder identification signal. In the timing control device, the distribution means predicts the ignition coil to be distributed this time from the ignition coil distributed last time, and distributes the drive signal to the predicted ignition coil when the predicted ignition coil differs from the ignition coil based on the cylinder identification signal. An ignition timing control device characterized by the above. 2. The distribution means distributes the drive signal to the ignition coil according to the cylinder identification signal when the predicted ignition coil and the ignition coil according to the cylinder identification signal are continuously different for a predetermined number of times. What is claimed is: Claim 1
An ignition timing control device according to the item.