JPH062641A - Ignition control device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent backfire caused by erroneous ignition of a cylinder in the intake stroke. [Structure] When the first pulse signal (97 ° signal) is output from the crankshaft sensor, the ignition cylinder is discriminated based on the number of pulse signals from the previous camshaft sensor, and the cylinder is determined as 2 cylinders.
Energization is started when the third pulse signal (65 ° signal) is output, and ignition is performed when the third pulse signal (10 ° signal) is output. Here, when the power supply to the ignition coil is started at an incorrect timing due to the noise N and the power supply is kept on, the power supply to the ignition coil is continued until the next regular ignition timing, and the false ignition is performed. To prevent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition control device for an internal combustion engine.

[0002]

2. Description of the Related Art As a conventional ignition control device for an internal combustion engine,
At the time of starting, there is one that performs control as shown in the ignition timing chart of FIG. 7, for example. This example is a 4-cylinder internal combustion engine, and the distribution of ignition is electronic distribution without a distributor.
It is assumed that a camshaft sensor for detecting a specific rotation position of the rotating camshaft is provided, and a crankshaft sensor for detecting a specific rotation position of the crankshaft is provided for detecting a crank angle.

Also, in this example, the ignition sequence is # 1 → # 3.
→ # 2 → # 4, # 1 and # 2 are simultaneously ignited as a first group, and # 3 and # 4 are simultaneously ignited as a second group. In these groups, when one cylinder is in the compression stroke, the other cylinder is in the exhaust stroke. Further, in this example, the ignition timing is fixed because it is the case of starting.

From the camshaft sensor, one pulse signal is output when the ignition cylinder is # 1, and two pulse signals are output when the ignition cylinder is # 3 so that the cylinders can be discriminated at least for each group. When the ignition cylinder is # 2, one pulse signal is output, and when the ignition cylinder is # 4, three pulse signals are output. From the crankshaft sensor,
Pulse signals are output at 97 °, 65 °, and 10 ° before the compression top dead center (TDC) of each cylinder.

Here, at 97 ° before TDC, cylinder discrimination is performed based on the number of pulse signals from the camshaft sensor up to that point. Therefore, the pulse signal from the camshaft sensor is 1
If one is output, this causes the ignition cylinder to be # 1 or #.
The cylinder can be determined to be 2, and the energization of the ignition coils of the # 1 and # 2 cylinders is started at 65 ° before TDC, and the energization is cut off at 10 ° before TDC to ignite. When the # 1 cylinder is the ignition cylinder (compression stroke), the # 2 cylinder is in the exhaust stroke, and there is no problem in igniting.

Next, when two pulse signals are output from the camshaft sensor, it can be determined that the ignition cylinder is # 3, and the ignition coils of the # 3 and # 4 cylinders can be detected at 65 ° before TDC. Start energization, cut off energization 10 ° before TDC, and ignite. Also in this case, the # 4 cylinder which is not the ignition cylinder is in the exhaust stroke, and there is no problem in igniting. Next, when one pulse signal is output from the camshaft sensor, the cylinder can be discriminated as the ignition cylinder is # 2 together with the previous cylinder discrimination, and TD
The energization of the ignition coils of the # 1 and # 2 cylinders is started at 65 ° before C, and the energization is cut off at 10 ° before TDC to ignite. Also in this case, the # 1 cylinder that is not the ignition cylinder is in the exhaust stroke, and there is no problem in igniting it.

Next, when three pulse signals are output from the camshaft sensor, it can be determined that the ignition cylinder is the # 4 cylinder, and the ignition coils of the # 3 and # 4 cylinders are output at 65 ° before TDC. Start energization, cut off energization 10 ° before TDC, and ignite. Also in this case, the # 3 cylinder, which is not the ignition cylinder, is in the exhaust stroke, and there is no problem even if it is ignited. FIG. 8 shows the state of control at the start of starting.

For example, if the engine is started from a state where it is stopped between 97 ° and 65 ° before TDC, two pulse signals are output from the crankshaft sensor, but the timing of cylinder discrimination is determined by the camshaft sensor. Since the timing at which the first pulse signal from the crankshaft sensor is generated after the pulse signal is output from, the cylinder determination is not performed at this stage.

The pulse signal from the camshaft sensor is 3
After the first output, the crankshaft sensor outputs the first pulse signal (97 ° signal), cylinder discrimination is made,
The ignition cylinder is determined to be # 4. Therefore, after that, when the second signal (65 ° signal) is output from the crankshaft sensor, energization to the ignition coils of the # 3 and # 4 cylinders is started and the third signal (10 ° signal) is started. ) Is input, the power is cut off and ignition is performed.

[0010]

However, in such a conventional ignition control device, if noise (starter noise or the like) is added to the output of the camshaft sensor, a misjudgment is caused, which results from this. Then, there is a problem that a cylinder in the intake stroke (intake valve open state) may be ignited by mistake and backfire may occur in the intake passage.

FIG. 9 shows the state of control when the camshaft sensor is started under the same conditions as in FIG. 8 and noise is present in the output of the camshaft sensor. When noise (N in the drawing) is added to the output of the camshaft sensor, it is regarded as a pulse signal, and when the 65 ° signal from the crankshaft sensor appears next time, the cylinder discrimination condition is satisfied, so this 65 ° signal is satisfied. Is determined to be a 97 ° signal, the cylinder is determined, and the ignition cylinder is the # 1 cylinder or #
It is determined that the number of cylinders is two. Then, when a 10 ° signal appears next time, this 10 ° signal is erroneously determined to be a 65 ° signal,
Energization will start for the ignition coils of the # 1 and # 2 cylinders. However, the opportunity for ignition is lost.

The pulse signal from the camshaft sensor is 3
After the first output, the crankshaft sensor outputs the first pulse signal (97 ° signal), cylinder discrimination is made,
The ignition cylinder is determined to be # 4. Therefore, after that, when the second signal (65 ° signal) is output from the crankshaft sensor, energization to the ignition coils of the # 3 and # 4 cylinders is started, but at this point, the energization is continued. The power supply to the ignition coils of the # 1 and # 2 cylinders, which had been set to, was stopped.

Therefore, at this time, the # 1 and # 2 cylinders are ignited and the # 1 cylinder is in the intake stroke.
This may cause backfire. Although fuel is not injected from the fuel injection valve before backfire occurs due to such misfiring, there is fuel left in the intake passage immediately before the engine is stopped or fuel leaking from the fuel injection valve. Therefore, combustion is possible.

In this way, when a backfire occurs in the intake passage, the backfire causes a temporary oxygen deficiency in the intake passage. When fuel is injected in this state, the air-fuel mixture becomes rich. , This makes starting difficult. The present invention has been made in view of such conventional problems, and an object of the present invention is to prevent occurrence of backfire due to erroneous ignition of a cylinder in the intake stroke based on erroneous determination.

[0015]

Therefore, according to the present invention, as shown in FIG. 1, a cylinder discriminating means for discriminating the ignition cylinder for each ignition cycle, and an ignition coil for the ignition cylinder after the discrimination of the ignition cylinder are provided. An ignition control device for an internal combustion engine, comprising: a timing discrimination means for discriminating an energization start timing and an ignition timing; and an ignition control means for controlling ignition based on the discrimination results of the cylinder discrimination means and the timing discrimination means. The configuration is provided with an erroneous discrimination detecting means for detecting erroneous discrimination, and an energization continuation means for continuing energization to the ignition coil of the cylinder currently energized at the time of erroneous discrimination detection until the next regular ignition timing of the cylinder. is there.

[0016]

In the above configuration, even if the energization start timing is erroneously determined, when the erroneous determination is detected, the energization of the ignition coil of the currently energized cylinder is not immediately interrupted, but is continued until the next regular ignition timing of the cylinder. Therefore, it is possible to avoid erroneously igniting the cylinder in the intake stroke, thereby preventing the occurrence of backfire.

[0017]

EXAMPLE An example of the present invention will be described below. FIG. 2 shows a system diagram. This example is a 4-cylinder internal combustion engine, and there are four spark plugs 1 corresponding to the cylinders # 1 to # 4.

The ignition order is # 1 → # 3 → # 2 → #
In step 4, # 1 and # 2 are connected as a first group to a common ignition coil 2A, and # 3 and # 4 are connected as a second group to a common ignition coil 2B. The ignition coils 2A and 2B are turned on and off by signals from the control unit 3, respectively.

Signals from the cam shaft sensor 4, the crank shaft sensor 5, the start switch 6 and the like are input to the control unit 3. From the camshaft sensor 4, one pulse signal is output when the ignition cylinder is # 1, and the ignition cylinder is
When it is 3, two pulse signals are output and the ignition cylinder is #
When it is 2, one pulse signal is output and the ignition cylinder is #
When the number is 4, three pulse signals are output (see FIG. 7).

From the crankshaft sensor 5, pulse signals are output before compression top dead center (TDC) of each cylinder, at 97 °, 65 °, and 10 ° (see FIG. 7). The control unit 3 controls the output to the ignition coils 2A and 2B by executing the ignition control routine (corresponding to the ignition control means including the cylinder determination means and the timing determination means) shown in the flowchart of FIG. . However, this routine is used for ignition control at the time of starting.

In step 1 (denoted as S1 in the drawing; the same applies hereinafter), various signals from the camshaft sensor, crankshaft sensor, start switch, etc. are input. In step 2, it is determined based on the signal from the start switch whether or not the engine is starting, and if it is, the process proceeds to step 3. In step 3, the value of the cylinder determination start flag KF is determined.

When KF = 0, the routine proceeds to step 4, where it is judged whether or not the first signal from the camshaft sensor (denoted as "CamSen" in the flow chart) is inputted.
When the first signal is input, the routine proceeds to step 5, where the cylinder discrimination start flag KF is set to 1, and the count value C is set to 0 at step 6. As a result, after KF = 1, the routine proceeds from step 3 to steps 7 and 13 and is repeatedly executed as long as it is determined at step 2 that the engine is starting.

In step 7, it is determined whether or not a signal from the crankshaft sensor (denoted by Classen in the flow chart) is input, and if there is input, step 8 is performed.
Then, the count value C is incremented by 1, and the value of the count value C is determined in step 9, and according to this value (1 to 3), the process branches to step 10 to step 12 and is described with reference to FIGS. 6
Each of the subroutines shown in is executed.

In step 13, it is determined whether or not there is a signal from the camshaft sensor (the signal from the second time onward), and if there is an input, the process proceeds to step 14 to store the current count value C as C ', Clear the count value C in step 15 of (C
= 0). Next, the subroutine shown in FIGS. 4 to 6 will be described. The subroutine of FIG. 4 is executed when C = 1, that is, by the 97 ° signal.

In step 21, cylinder discrimination of the ignition cylinder is performed based on the number of pulse signals from the cam shaft sensor immediately before that. In step 22, it is determined whether C '= 3.
When C '= 3, it is normal, and the routine proceeds to step 23, where the misjudgment flag GF is set to 0. If C ′ ≠ 3, the result is the result of misjudgment. Therefore, the process proceeds to step 24 and the misjudgment flag G
Set F to 1. This portion corresponds to erroneous discrimination detection means.

The subroutine of FIG. 5 is executed when C = 2, that is, with the 65 ° signal. In step 31,
It is determined whether the erroneous determination flag GK is set,
When GK = 0, the routine proceeds to step 32, where energization is started to the ignition coils of the group including the ignition cylinder.

When GK = 1, the routine proceeds to step 33, where it is judged whether or not the ignition coils of the cylinders other than the group including the ignition cylinder are currently energized. While continuing to energize the ignition coils of other cylinders that are energized, energization is started to the ignition coils of the group including the ignition cylinder. This portion corresponds to the energization continuation means.

The subroutine of FIG. 6 is executed when C = 3, that is, by the 10 ° signal. In step 41,
It is determined whether the erroneous determination flag GK is set,
If GK = 0, the routine proceeds to step 42, where the energization of the ignition coils of the group including the ignition cylinder is cut off to ignite.

When GK = 1, the routine proceeds to step 43, where it is judged whether or not the ignition coils of the cylinders other than the group including the ignition cylinder are currently energized. While continuing to energize the ignition coils of the other cylinders that are energized, the ignition is interrupted by interrupting the energization of the ignition coils of the group including the ignition cylinder. This part also corresponds to the energization continuation means.

Next, for example, if the engine is 97 ° and 65 ° before TDC
When starting from the state where it is stopped between
explain. When there is no influence of noise or the like, the process is the same as that of FIG. 8 showing the state of control at the start of starting. FIG. 10 shows the state of control when the engine is started under the same conditions as in FIG. 8 and noise is added to the output of the camshaft sensor as in FIG.

When noise (N in the figure) is added to the output of the camshaft sensor, it is regarded as a pulse signal, and when the 65 ° signal from the crankshaft sensor appears next time, the cylinder discrimination condition is satisfied. The 65 ° signal is erroneously determined to be a 97 ° signal, the cylinder is determined, and the ignition cylinder is the # 1 cylinder or #
It is determined that the number of cylinders is two. Then, when a 10 ° signal appears next time, this 10 ° signal is erroneously determined to be a 65 ° signal,
Energization will start for the ignition coils of the # 1 and # 2 cylinders.

The pulse signal from the camshaft sensor is 3
After the first output, the crankshaft sensor outputs the first pulse signal (97 ° signal), cylinder discrimination is made,
The ignition cylinder is determined to be # 4. Therefore, after that, when the second signal (65 ° signal) is output from the crankshaft sensor, energization to the ignition coils of the # 3 and # 4 cylinders is started, but at this point, the energization is continued. Without interrupting the power supply to the ignition coils of the # 1 and # 2 cylinders
Continue energizing.

After that, when the third signal (10 ° signal) is output from the crankshaft sensor, the power supply to the ignition coils of the # 3 and # 4 cylinders is cut off to ignite. Energization is continued without interrupting the energization to the ignition coils of the # 1 and # 2 cylinders that have been energized. In this way, the ignition coils of the # 1 and # 2 cylinders continue to be energized until the regular ignition timing thereafter, and at the regular ignition timing, the energization is cut off to ignite. As a result, it is possible to prevent the occurrence of backfire due to erroneous ignition in the intake stroke.

In the above description, the starting time is taken as an example, but the present invention is not limited to this. However, during normal operation, if the energization time is long, there is a risk of burning due to overheating of the ignition coil, but at the time of start-up there is no problem even if the energization is continued because the temperature is low, and the influence of starter noise is large. It can be said that it is preferable to carry out at the time of starting.

[0035]

As described above, according to the present invention, even if the energization start timing is erroneously discriminated and the energization is started, the energization is not immediately interrupted at the time of detection of the erroneous discrimination until the next regular ignition timing. Since it is continued, it is possible to avoid erroneously igniting the cylinder in the intake stroke, and thus it is possible to prevent the occurrence of backfire.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention.

FIG. 2 is a system diagram showing an embodiment of the present invention.

FIG. 3 is a flowchart of an ignition control routine.

FIG. 4 is a flowchart of a C = 1 subroutine.

FIG. 5 is a flowchart of a C = 2 subroutine.

FIG. 6 is a flowchart of a C = 3 subroutine.

FIG. 7 is an ignition timing chart at the time of starting.

FIG. 8 is a diagram showing a state of control at the start of starting.

FIG. 9 is a diagram showing a state of control when noise is generated at the start of a conventional process.

FIG. 10 is a diagram showing a state of control when noise is generated at the start of starting according to the present invention.

[Explanation of symbols]

 1 Spark Plug 2A, 2B Ignition Coil 3 Control Unit 4 Cam Axis Sensor 5 Crank Axis Sensor 6 Start Switch

Claims (1)

[Claims] 1. A cylinder discriminating means for discriminating an ignition cylinder for each ignition cycle, a timing discriminating means for discriminating a start timing and an ignition timing of energization of an ignition coil of the ignition cylinder after the discrimination of the ignition cylinder, and the cylinder discriminating means. And an ignition control device for an internal combustion engine, comprising: an ignition control means for controlling ignition based on the determination result of the timing determination means,
An erroneous discrimination detecting means for detecting erroneous discrimination of the timing discrimination means, and an energization continuation means for continuing energization to the ignition coil of the cylinder currently energized at the time of erroneous discrimination detection until the next regular ignition timing of the cylinder are provided. An ignition control device for an internal combustion engine, comprising: