JPS62223467A - Ignition control device for engine - Google Patents

Abstract

PURPOSE:To make it possible to restrain knocking through the control of ignition without the output or the like of the engine being lowered, by increasing the ignition energy during occurrence of knocking. CONSTITUTION:A knocking sensor 27 detects vibration of an engine 1, and a knocking detecting circuit 28 detects knocking. When a control unit 20 detects occurrence of knocking, the time of energization of an ignition plug 3 by a distributor 10 is made to be long in order to increase the ignition energy if the intensity of the knocking is less, and therefore, the speed of combustion in a combustion chamber 2 is increased to restrain occurrence of knocking without the output of the engine being lowered. Meanwhile, if knocking may not be restrained by increasing the ignition energy or if the intensity of knocking is large, the ignition timing is retarded to surely restrain occurrence of knocking.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine ignition control device that performs ignition control in response to knocking.

(Prior art #! 4) Conventionally, there is a known technology in which when the occurrence of knocking is detected during engine operation, the ignition timing is delayed to suppress the occurrence of knocking (for example, Japanese Patent Laid-Open No. 56 -23566).

However, suppressing knocking by delaying the ignition timing as described above increases the exhaust temperature by 6.
There are also problems such as a decrease in engine output, and it is desired to suppress knocking without having such negative effects as a decrease in engine output.

(Object of the Invention) In view of the above circumstances, an object of the present invention is to provide an engine ignition control device that suppresses knocking through ignition control without reducing engine output. .

(Structure of the Invention) The ignition control device of the present invention includes a knocking detection means for detecting the occurrence of knocking or an operating region where knocking occurs, and receives an output of the knocking detection means to increase ignition energy when knocking occurs or in the knocking occurrence region. ignition energy increasing means.

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

An ignition control means 4 is provided for controlling the ignition timing, discharge time, etc. of the ignition plug 3 disposed facing the combustion chamber 2 of the engine 1 in accordance with the operating state.

On the other hand, the knocking detection means 5 is configured to detect knocking from the vibration of the engine 1 or from the fact that the operating state is in the knocking occurrence range.
Upon receiving the signal from the knocking detection means 5, the ignition energy increasing means 6 controls the ignition control means 4 when knocking occurs.
A signal is output to increase the ignition energy, and the ignition plug 3 performs high-energy ignition.

The ignition energy at J3 is increased by lengthening the discharge time (current application time) or by increasing the discharge voltage. For example, by lengthening the discharge time, the ignition action of the long discharge time ignites the air-fuel mixture in the combustion chamber 2 over a wide range, increasing the combustion speed, thereby suppressing knocking. Further, by reducing the discharge voltage, the combustion rate can be similarly improved and knocking can be suppressed.

(Effects of the Invention) According to the present invention, when knocking occurs, the ignition energy is increased to suppress knocking, so that knocking can be suppressed without reducing engine output or the like. Further, when knocking is not occurring, the ignition energy is not increased, thereby improving the durability of the spark plug and reducing unnecessary power consumption.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 2 is an overall configuration diagram of a specific example.

An ignition plug 3 is disposed facing the combustion chamber 2 of the engine 1, and a discharge voltage from a distributor 10 is applied to the ignition plug 3. An ignition signal is input through a DC/DC converter 12 that adjusts the energization time (discharge time).

On the other hand, an intake passage 1 that supplies intake air to the combustion chamber 2 of the engine
3, an air cleaner 14, an air flow meter 15 for measuring intake air R, a throttle valve 16 for controlling the intake air mass, and an injector 17 are installed in this order from the upstream side. Further, the downstream portion of the intake passage 13 near the combustion chamber 2 is divided into a low-load passage 13a and a high-load passage 13b, and a swirl valve 19 is connected to the high-load passage 13b by the operation of the actuator 18. is interposed.

Ignition timing and DC/[) by the ignition system 11
The energization time of the C converter 12 is controlled by a control signal from the control unit 20, and the control unit 20 also controls the swirl control corresponding to the fuel supply (air-fuel ratio) by the injector 17 and the opening/closing of the swirl valve 19 by the actuator 18. ill 1211 by control signals from.

In order to detect the operating state of the engine, the control unit 20 detects an intake air ω signal from an air flow meter 15, an intake air temperature signal from an intake air temperature sensor 21 that detects the intake air temperature, and the fully open state of the throttle valve 16. An idle signal from the idle switch 22, a water temperature signal from the water temperature sensor 23 that detects the cooling water temperature, a start signal from the starter switch 24, and an air-fuel ratio signal from the air-fuel ratio sensor 26 installed in the exhaust passage 25 are input, respectively. At the same time, a signal from a knock sensor 27 that detects engine vibration is inputted via a knock detection circuit 28, and a crank angle signal that detects engine rotation is inputted from the distributor 10.

The control unit 20 has the functions of each means shown in FIG. 1, and when knocking is detected and the knock intensity is small, the control unit 20 controls to increase the ignition energy by increasing the energization time. When knocking cannot be suppressed by increasing the ignition energy, or when the knock intensity is large, control is performed to delay the ignition timing and suppress the occurrence of knocking.

In addition, the air-fuel ratio sensor 2 adjusts the fuel injection m according to the operating condition.
Feedback control is performed to the target value in response to the output of No. 6, and furthermore, at low loads with little intake m, the swirl valve 19 is closed to generate a strong swirl, while at high loads, the swirl valve 19 is opened to increase the intake port. Perform swirl control like this.

The operation of the control unit 20 will be explained based on the flowcharts shown in FIGS. 3 to 7. This flowchart only shows the ignition control routine associated with the occurrence of knocking.

Figure 3 shows the main routine. After starting, the system is initialized in step S1, and in steps S2 to S7, the intake air amount, water temperature, intake air temperature, etc. are determined based on signals from various sensors.
Read the air-fuel ratio signal, idle signal, and starter signal.

Subsequently, in step S8, it is determined whether or not it is starting time, and if starting time (YES), in step S9, switching to mechanical fixed ignition (hard ignition) for starting time is performed, and ignition at starting time is performed.

On the other hand, after starting, in step S10 the engine is switched to soft ignition, which controls the ignition characteristics to match the ignition characteristics determined by the program in accordance with the operating state.

Then, in step S11, it is determined whether it is in an idle state,
When idle (YES), steps S12 and 81
In Step 3, the energization time (discharge time) and ignition timing for idling are calculated, and in step S17, the energization time and ignition timing are preset in a counter to perform predetermined ignition.

If the determination in step 811 is No and the operating state is other than idling, the detailed routine for setting the knock control in step 814 is shown in FIG. 5), and the detailed routine for determining the energization time in step S15 is shown in FIG. Furthermore, in step 816, the ignition timing is calculated (the detailed routine is shown in FIG. 7), and in step 817, the energization time and ignition timing of the lever are preset in a counter to perform predetermined ignition.

FIG. 4 shows an interoperable routine that performs interrupt processing at every predetermined crank angle. For example, after starting the interrupt at the top dead center crank angle, the cycle from the previous interrupt is calculated in step 818, and based on this cycle, Step 8
In step 19, the engine rotation speed is determined by converting it into a rotation speed.

Next, FIG. 5 shows the knock control setting routine,
This is used to set whether or not to correct the ignition energy or ignition timing in response to the occurrence of knocking. In step 820, it is determined whether the operating condition meets the knock control condition or not, and the determination is made based on whether the operating condition is in the knocking occurrence region of the high load and low rotational speed region. If this determination is YES and the knocking occurrence region is present, the knock determination flag Fn is set to 1 in step S21, and then the knock intensity 1k detected by the signal of the knock sensor 27 is read in step S22.

Then, in step 823, the ignition timing correction flag Ft is set to 0.
If YES, the knock intensity average memory is shifted by 1 byte in step S24, and in step 825, the knock intensity 1k is stored in the average memory as the latest value. In step 826, the first average value AO of the knock intensity 1 is determined by weighting the old data, and in step 827, the second average value 80 of the knock intensity 1 is determined by weighting the new data.

Next, in step 328, the knock intensity 1k is set to a predetermined value.
It is determined whether the knock intensity is greater than the predetermined value K.
When the answer is No below i, the ignition energy correction flag Fe is set to 1 in step S31. On the other hand, knock strength 1k
is larger than the predetermined value Kt, step 829
Set the ignition timing correction flag F to 1, and
At step 830, the ignition energy correction flag Fe is reset. This sets whether to perform knock control based on ignition energy or ignition timing. That is, when the knock intensity Ik is large and it is difficult to suppress knocking by controlling the ignition energy, knocking is suppressed by retarding the ignition timing.

Note that if the determination in step 820 is NO and the operating state is not in the knock control region, the knock intensity average memory is cleared in step 832, and the knock strength average memory is cleared in step 832.
Clear the various flags in step 3.

FIG. 6 shows the routine for calculating the energization time, and first,
In step S34, a basic energization time Tll is calculated from the engine speed and intake air amount. This basic energization time Tb is
The larger the filling meter (intake air port/engine speed) is, the longer it becomes. Subsequently, in steps 835 to 838, water temperature correction 1 shift Twt is performed.

An intake temperature correction value Tat, an air-fuel ratio correction value Taf, and a swirl correction value Ts are calculated. The above water temperature correction value Tw
t increases the energization time because combustion is unstable at low water temperatures, and the intake air thirst correction value at increases the energization time because low intake temperatures make it difficult to ignite the air, and the air-fuel ratio correction value Taf The more the air-fuel ratio is away from the stoichiometric air-fuel ratio (IL7), the more difficult it is to ignite, so the energization time is increased.
Further, the swirl correction value Ts increases the energization time because the smaller the opening degree of the swirl valve 19 and the larger the intake flow rate, the more difficult it is to ignite.

Further, in steps 839 to 359, a knock correction value Tk for the energization time is calculated, and in step S60, each of the above correction values is added to the basic energization time Tb to calculate the final energization time T.

In calculating the knock correction value Tk, step S39 is a step in which it is determined whether the knock determination flag Fn is set to 1, and if YES is in the knock control region.
Sometimes, in step 840, the ignition energy correction flag Fe
is set to 1.

When the determination in step S40 is YES and the ignition energy is corrected, the knock intensity 1k is set to 0 in step S41.
If the determination is YES and knocking has occurred, a correction value Tkc corresponding to the knock intensity 1k is read from the map in step S42. This map is set so that the larger the knock intensity 1k is, the larger the correction value 1-kc is, that is, the longer the energization time becomes.
At step 44, the knock correction value Tk is calculated by adding the correction value Tkc.

If the determination in step 841 is No and knocking has not occurred, the correction value Tkc is set to a predetermined value Kr (negative value) in step S43 in order to shorten the energization time.
, and in step 844, the knock correction value Tk is subtracted. Then, it is determined in step S/15 whether or not the calculated knock correction value Tk is a negative value less than 0. If the determination is YES and the knock correction value Tk is a negative value, the knock correction value Tk is determined in step S/15. Set the value Tk to 0.

On the other hand, if the determination in step 845 is NO, knock correction [Tk
When is greater than or equal to 0, the process proceeds to step 852, where it is determined whether or not the knock correction value Tk is greater than the upper limit value Tko. Until the knock correction value Tk reaches the upper limit value Tko, the knock correction value Tk corresponding to the knock intensity 1k is determined and energization is performed. Calculate the time. That is, when knocking occurs, control is performed such that the greater the knock intensity, the larger the knock correction value Tk to lengthen the energization time, and when the knocking subsides, the energization time is shortened.

The knock correction value Tk becomes larger than the upper limit value 7ko,
If the determination in step 852 is YES, step 85
3, the difference Ad between the first average value AO and the second average value An, that is, the change value of the knock intensity is calculated. Then, in step 354, it is determined whether the knock intensity change value Ad associated with the control to increase the ignition energy using the knock correction value Tk has been reduced to a predetermined value by a value greater than 2, and the C knocking suppression has been effective. If this determination is YES and is valid, the validity determination flag Fc is set to 1 in step 855, while if NO is not valid, the validity determination flag Fc is reset in step 856. Roughly speaking, in order not to further increase the energization time even though the knock correction value Tk is the upper limit value, the ignition energy correction flag FO is reset in step S57, and the ignition timing correction flag F[ is set in step S858. From now on, the engine will shift to suppressing knocking by correcting the ignition timing.

Further, when the knock correction 1 shift Tk becomes lower than the upper limit value ko and the ignition energy correction flag Fe becomes 0, the step 8
40, the process proceeds to step 847, where it is determined whether or not the validity determination flag Fc is set. When this determination is No and the ignition energy increase is effective,
The energization time remains increased. On the other hand, this step S
When the determination in step 47 is YES, the Zunawara validity determination flag FC is reset, and when the knocking suppression by increasing the ignition energy is not effective, the energization time shortening flag Ff is set in step 848 to shorten the energization time. It is determined whether or not there is, and when the reset is YES, a predetermined value Kd is subtracted from the knock correction value Tk in step 849.

Then, it is determined in step S50 whether or not the knock correction value Tk has become negative, and the knock correction value 1'-k is decreased until this determination becomes YES, and when the determination is YES in step S50, the energization time is determined in step S51. The shortening flag F'' is set, and the knock correction value Tk is set to 0 in step 846.

In other words, if extending the 17gT during energization has the effect of suppressing knocking, the control moves on to the next ignition timing while keeping the energization time longer, but if it is not effective, the electrical load is reduced. Therefore, the current application time, which had been long, will be gradually shortened to prevent shocks.

Note that when the operating state is out of the knocking region and the knock determination flag Fn has been reset, the knock correction value Tk is set to O in step 359 due to the No determination in step 839.

Next, FIG. 7 shows an ignition timing calculation routine. First, in step S60, a basic ignition timing θb is calculated from the engine speed and intake air amount. This basic ignition timing θb is 1i
The larger the WM (intake air amount/engine speed), the more the ignition timing is advanced. Subsequently, step 861~
At 864, the water temperature correction value θW[, the intake temperature correction value θat, the air-fuel ratio correction value θat, and the acceleration correction value θaC are calculated. The above water temperature correction value θW is to advance the ignition timing because the combustion speed is low at low water temperatures, and the intake temperature correction value θ
a [ is to retard the ignition timing as the combustion speed increases as the intake temperature increases, and the air-fuel ratio correction value θar advances the ignition timing as the air-fuel ratio becomes richer. The value θaC is used to retard the ignition timing since knocking is likely to occur during acceleration.

Further, in steps 865 to 871, a knock correction value θ for the ignition timing is calculated, and in step S72, each of the above compensation iE
The final ignition timing θ is obtained by adding irT to the basic ignition timing θb.
Calculate.

In calculating the knock correction value Ok, step S65 is to determine whether the knock determination flag FO is set to 1, and if YES is in the knock control region.
Sometimes, the ignition timing correction flag Ft is set to 1 in step S66.
Determine whether it is set to . This judgment is YES
When correcting the ignition timing in step S, it is determined in step 867 whether or not the knock intensity 1k is not O, that is, whether or not knocking is occurring.If this determination is YES and knocking has occurred, the knock intensity is adjusted in step 868. A correction value θkc corresponding to 1k is read from the map. This correction value θkc has a larger negative value, that is, a larger retard amount, as the knock intensity rlick increases, and in step 871, the knock correction value θk is calculated by adding 0 to the correction value θkc. Further, if the determination in step S67 is No and knocking has not occurred, then in step S69 the correction value θkc is set to a predetermined value KS (positive value, that is, advance angle can), and in step S71 the knock correction value is similarly set. Find θk.

Note that when the operating state is out of the knocking region and the knock determination flag Fn is reset, the ignition timing correction flag Fn is also reset due to the No determination in step 865.
When t has been reset, the knock correction value θk is set to O in step S70 due to the No determination in step S66.

According to the embodiment described above, by selectively controlling the energization time when knocking occurs, that is, controlling the ignition energy and ignition timing, it is possible to prevent a decrease in engine output due to an increase in the energization time in the event of slight knocking. While this suppresses the occurrence of knocking without any accompanying noise, when greater knocking occurs, it reliably suppresses the occurrence of knocking through ignition control.

In the above embodiment, knocking is detected based on the determination of the knocking area and the determination of the actual occurrence of knocking, but the knocking is detected based on either one of the determinations. Good too. Further, in the above embodiment, knocking is suppressed by a combination of energization time, that is, ignition energy and ignition timing, but ignition energy control and other knocking suppression means may be combined. be. Roughly speaking, the ignition energy may be controlled to increase uniformly when knocking occurs, regardless of the intensity of knocking.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram to clarify the configuration of the present invention, FIG. 2 is an overall configuration diagram showing a specific example, and FIGS. 3 to 7 are 70-diagram diagrams to explain the operation of the control unit. It is. 1... Engine 3... Spark plug 4... Ignition control means 5... Knocking detection means 6... Ignition energy increasing means 10. ...Distributor 11...Ignition system 12...DC/DC converter 20...
・Control unit 27...Knock sensor 28...Knock detection circuit Fig. 1

Claims (1)

[Claims] (1) It is equipped with a knocking detection means for detecting the occurrence of knocking or an operating region where knocking occurs, and an ignition energy increasing means that receives the output of the knocking detection means and increases the ignition energy when knocking occurs or in the knocking occurrence region. An engine ignition control device featuring: