JPS61118563A - Ignition timing control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent harmful exhaust gas from being increased upon cooling and the like by providing judgment means for judging whether or not MBT control should be performed of maximizing produced torque in response to operation parameters of an engine. CONSTITUTION:A MBT control judgment circuit 26 judges whether or not operation conditions necessitates MBT control, said MBT control controlling ignition timing so as to permit thetapmax by a detector circuit 21 to accord with a target value based on engine rpm and load specified by a judgment result by a cooling water temperature judgment circuit 25, a signal from an air- flowmeter, and a signal from a crank angle sensor 14. For example, in warming operation and in cranking or in low load, a signal indicative of no correction is delivered to an ignition lead angle correction circuit 23, whereby the ignition lead angle correction circuit 23 issues no correction value independently of a result of a comparator 23 while an ignition lead angle set circuit 23 does not correct a basic ignition lead angle and not exhibit MBT control.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an ignition timing control device for an internal combustion engine.

[Conventional technology]

As a conventional ignition timing control device for an internal combustion engine, there is 1, for example, as seen in Japanese Patent Application Laid-Open No. 58-82074.
There is a method in which the pressure inside the cylinder (combustion chamber) of an engine is detected and the ignition timing is controlled so that the crank angle position (θρmax) at which the pressure is maximum matches a target value.

Although there are some differences depending on the engine, as shown in Fig. 7, the crank angle position θ at which the cylinder internal pressure reaches the maximum Pmax
If the ignition timing θ0 is controlled so that pmax is at a position of 10'' to 20'' after TDCC (top dead center), the generated torque of the engine can be maximized.

Ignition timing control using this method is called MBT control.

[Problems to be Solved by the Invention] However, the conventional ignition timing control device of this type does not perform the above-mentioned MBT control based on engine operating parameters such as engine speed, cooling water temperature, and load.

This was done without considering cranking conditions etc.

Therefore, since MBT control is performed even under warm-up conditions when the catalyst temperature should be raised immediately, the temperature rise of the catalyst is delayed and harmful exhaust gas components increase.

In addition, during cranking, the power supply voltage of the input circuit decreases, resulting in inaccurate control, and when the load is low, θpma
There was a problem that x could not be detected.

The object of the present invention is to solve the problems in the conventional ignition timing control device that performs MBT control.

[Means for solving problems]

The ignition timing control device for an internal combustion engine according to the present invention includes an MBT
In the ignition timing control device that performs the control, a determination means is provided for determining whether or not to perform MBT control according to the operating parameters of the engine.
The above problem is solved by not performing MBT control when the operating conditions do not require T control.

[For production]

The determination means inputs engine operating parameters such as engine speed, cooling water temperature, load, or ON/OFF of the starter switch, and determines not to perform 1MBT control when the operating condition is such that MBT control should not be performed. Therefore, in that case, MBT control is not performed, and ignition is performed at the basic ignition advance angle determined by the engine speed, load, and cooling water temperature.

[Embodiment j] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a block configuration diagram of an ignition timing control device showing one embodiment of the present invention, and FIG. 2 is a system showing main parts of an internal combustion engine equipped with a control unit including the ignition timing control device of FIG. FIG.

First, referring to FIG. 2, reference numeral 1 denotes an air cleaner that removes dirt and dust from the intake air, 2 an air flow meter that measures the flow rate of the intake air, and 3 a throttle valve that is opened and closed by an accelerator pedal (not shown).

The air that flows into the intake pipe through these is mixed with fuel injected from the injector 5 in the intake manifold 4, becomes an air-fuel mixture, is drawn into the combustion chamber 6, is ignited by the spark plug 7 and burns, and the piston Drive 8.

Then, the exhaust gas after combustion is discharged to the outside through the exhaust manifold 9. The exhaust manifold S is equipped with a 0
Two sensors 10 are attached.

11 is a water temperature sensor attached to the cylinder block 12,
Detects engine coolant temperature.

13 is a distributor with a built-in crank angle sensor 14, which distributes the ignition pulse generated in one ignition coil 15 to the ignition plugs 7 attached to each cylinder, and also distributes the ignition pulse generated in one ignition coil 15 to the spark plugs 7 attached to each cylinder. generates a pulse signal (each time).

Furthermore, a washer-type cylinder pressure sensor 17 is installed as a washer for the spark plug 7 attached to the cylinder head 16. This cylinder pressure sensor 17 is composed of a piezoelectric element, and Outputs an electrical signal according to pressure.

The control unit 20 includes a cylinder pressure sensor 1
Signal Sin from water temperature sensor 11 S2. Signal from air flow meter 2 S3t crank angle sensor 1
signal S4y from 02 sensor 10 and signal S5 from 02 sensor 10
This device controls the fuel injection timing, injection amount, and ignition timing by inputting a signal S6 to drive the injector 5 and outputting an ignition signal S7 to the ignition coil 15.

Among the functions of this control unit 20, FIG. 1 shows the function as an ignition timing control device according to the present invention as a block diagram. )21
．． Comparator 222 ignition advance correction circuit 232 ignition advance setting circuit 24. Cooling water temperature discrimination circuit 25. and an MBT control determination circuit 26.

Next, the function of this control unit 20 as an ignition timing control device will be explained.

The detection signal S1 of the cylinder pressure sensor 17 and the signal for each predetermined rotation angle of the crankshaft from the crank angle sensor 14 (
For example, 1° pulse) S4 is input to the θpmax detection circuit 21, and for each combustion, the cylinder pressure maximum crank angle position θ
pmax is detected.

This θpHaX is compared with a target value by a comparator 22, and it is determined whether it is larger or smaller than the target value.

The ignition advance angle correction circuit 23 calculates a correction value for the ignition advance angle (ignition timing expressed in crank angle before top dead center) according to the determination result. That is, when θp+aax is larger than the target value, the ignition advance angle is increased to advance the ignition timing, and when it is smaller than the target value, the ignition advance angle is decreased to delay the ignition timing.

The ignition advance setting circuit 24 receives a signal S2. Signal S3r indicating intake air flow rate Q from air flow meter 2 and crank angle sensor 14
Input the signal S4 corresponding to the engine speed N from ! f
In addition to calculating the basic ignition advance angle suitable for the operating conditions of the i engine, the basic ignition advance angle is corrected using the correction value from the ignition advance correction circuit 23 to set the ignition advance angle, and the ignition signal S7 is sent to the ignition coil. Output to.

On the other hand, in order to determine whether one engine is warming up or has completed warming up, the cooling water temperature determination circuit 25 uses a signal S2 from the water temperature sensor 11 to determine whether the cooling water temperature Tw is the set temperature (for example, 5
0°C) or higher, and use the determination result as MBT.
Input to the control determination circuit 26.

The MBT control determination circuit 26 is based on this cooling water temperature determination circuit 25.
and the signal S3 from the air flow meter 2.
Based on the engine speed and load detected from the signal S4 from the crank angle sensor 14, it is determined whether or not the operating conditions are such that MBT control is performed to control the ignition timing so that θpmax matches the target value. .

When it is determined that MBT control should not be performed, a signal is output that does not cause the ignition advance correction circuit 23 to perform correction. As a result, regardless of the comparison result of the comparator 22, the 1 ignition advance angle correction circuit 23 no longer outputs a correction value.
The ignition advance setting circuit 24 outputs the ignition signal S7 without correcting the basic ignition advance angle. That is, MBT control is not performed at this time.

The control unit 20 actually includes a central processing unit (CPU) that controls calculations and judgments, and a ROM that stores processing programs, fixed data, etc.
, a random access memory (RAM) that stores input data and calculation results, and an input/output device (Ilo LSI).
), etc., and in that case, the functions of each circuit described above will be executed by the microcomputer through program processing.

A processing program related to ignition timing control similar to the embodiment shown in FIG. 1 in this case will be explained with reference to the flowchart shown in FIG. 3.

First, in step 1, the engine cooling water @Tw is measured based on the signal S2 from the water temperature sensor 11.

Next, in step 2, the intake air amount Qa is measured based on the signal S3 from the air flow meter 2. moreover.

In step 3, the engine speed N is measured based on the signal S4 from the crank angle sensor 14.

Then, in step 4, the basic fuel injection amount Tp is calculated from the intake air amount Qa and the engine speed N by calculating -Tp=-Qa/N. In addition.

K is a proportionality constant depending on the flow rate characteristics of the injector.

Various corrections are made to this basic fuel injection amount Tp to set the injection pulse that drives the injector 5 shown in FIG. 2, but this is also a value representing the engine load, and in the second embodiment 1 of the operating parameters of
This basic fuel injection amount Tp is used as a take for a certain load.

Next, in step 5, it is determined whether the cooling water temperature Tw is higher than the set temperature (506C in this example).

If YES, proceed to step 6 and move on to the next table 1.
Then, the control range coefficient β is looked up using the basic fuel injection amount Tp (representing the load) and the engine speed N as parameters. If NO in step 5, the control range coefficient β is looked up from the following Table 2 using the same <Tp and N as parameters.

Table 1 Table 2 In Tables 1 and 2, the control range coefficient β is indicated by l or 0, β=l is the range for MBT control, β=
0 is the range in which MBT control is not performed. , the second table is stored in advance in the ROM of the microcomputer.

Next, in step 8, the cylinder pressure maximum crank angle position Opmax is measured using the signal Sl from the cylinder pressure sensor 17 and the signals S and I from the crank angle sensor 14, and in step 9, the engine rotation speed N, the basic fuel A basic ignition advance angle ADV is calculated from the injection amount T P r and the engine coolant temperature Tw.

Then, in step IO, θpmax is compared with the target value. If θpn+ax is larger than the target value (YES).

Since the ignition timing is too late, proceed to step 11 and correct the ignition advance angle to ADV + α・β.

If θpmax is not larger than the target value (No), the ignition timing is too advanced, and the process proceeds to step I2 to correct the ignition advance angle to ADV-α·β.

Here α is the control gain.

However, the β looked up in step 6 or 7 is “
In the case of "0", since α and β=0, the ignition advance angle remains at the basic ignition advance angle ADV and no correction is performed. That is, M
BT control will not be performed.

FIG. 4 is a diagram similar to FIG. 2 showing another embodiment of the present invention, and the difference from FIG.
Voltage signal S8 by battery IS indicating on/off of 8
is input to the control unit 20'.

As shown in FIG. 5, the control unit 20' is also constructed in substantially the same manner as the control unit 20 of the above-described embodiment shown in FIG. 22 and the determination result of the MBT control determination circuit 26, the starter switch 18 is turned on and off.
A signal S8 indicating off is also input, and the starter switch 18
When is on, that is, during cranking, the ignition advance angle correction value is not output regardless of the determination result of the MBT control determination circuit 26.

Therefore, according to this embodiment, MBT control is not performed during cranking regardless of other operating parameters. In this case, the 1-ignition advance angle correction circuit 23' also has the function of determining means. The other functions are the same as those in the previous embodiment, so their explanation will be omitted.

Next, a processing program relating to ignition timing control when the control unit 20' of the embodiment shown in FIGS. 4 and 5 is configured by a microcomputer will be explained with reference to the flowchart shown in FIG.

Steps 1 to 12 are the same as those in FIG. 3, so their explanation will be omitted. However, between step 9 and step 10, step 15 is inserted to determine whether the starter switch is on, and the starter switch 18 is turned on. If off, step 1
The process proceeds to 0 and compares 0ρn+ax with the target value, but if it is on, the process proceeds to step 16 and leaves the 5 ignition advance angle as the basic ignition advance angle ADV calculated in step 9. That is, MBT control is not performed at this time.

In addition, in each of the above-mentioned embodiments, 2
Alternatively, another method may be used, such as setting the MBT control to not be performed in the entire area when the cooling water temperature is below a predetermined water temperature.

[Effect of the Invention J As explained above, the ignition timing control device for an internal combustion engine according to the present invention performs MBT control to control the ignition timing so that the crank angle position where the cylinder pressure is maximum matches the target value. A determining means is provided for determining whether or not MBT control is to be performed, not always, but according to the operating parameters of one engine.

Based on the judgment result, MBT control is not performed when the operating conditions are such that MBT control should not be performed.1 For example, MBT control is not performed during warm-up (when cold), during cranking, or at low load. You can do it like this.

As a result, when the engine is cold, the ignition timing is delayed and the exhaust temperature rises, causing the catalyst temperature to rise faster.

It is possible to prevent an increase in harmful waste residue components. It is also possible to prevent abnormal control during cranking or under low load.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a control unit (ignition timing control device) according to an embodiment of the present invention and its input/output relationship, and FIG. FIG. 6 is a flowchart showing a processing program related to ignition timing control according to the present invention executed by the microcomputer of the control unit 20. FIG. 4 is a system configuration diagram showing the ignition timing control according to the present invention. FIG. 5 is a block diagram showing the configuration of the control unit 20' and its input/output relationship. FIG. 6 shows the microcomputer of the control unit 20'. A flowchart showing a processing program related to ignition timing control according to the second invention to be executed, FIG. 7 is a diagram showing the relationship between cylinder internal pressure and crank angle. 2... Air flow meter 3... Throttle Valve 4... Intake manifold 5... Injector 6... Combustion chamber 7... Spark plug 8... Piston 9... Exhaust manifold 11... Water temperature sensor 13... Distributor 14... ...Crank angle sensor 15...Ignition coil 1
7... Cylinder pressure sensor 18... Starter switch 20.20'... Control unit 21...
Cylinder pressure maximum position detection circuit 22...Comparator 2), 2!1'...Ignition advance angle correction circuit 24...Ignition advance setting circuit 25...Cooling water temperature discrimination circuit 26...MBT control Judgment circuit

Claims (1)

[Claims] 1. A cylinder pressure detection means of an internal combustion engine, and a means for controlling ignition timing so that the crank angle position at which the cylinder pressure detected by the detection means is at its maximum matches a target value. In the ignition timing control device, there should be provided a determination means for determining whether or not to perform the ignition timing control according to engine operating parameters, and the ignition timing control should be performed based on the determination result of the determination means. 1. An ignition timing control device for an internal combustion engine, characterized in that the ignition timing control is not performed under operating conditions in which the ignition timing control is not performed. 2. Claim 1, characterized in that the determining means is means for determining whether or not to control the ignition timing according to engine operating parameters such as engine speed, cooling water temperature, and load. An ignition timing control device for an internal combustion engine as described in 2. 3. Claim 2, characterized in that the determining means stores a plurality of tables in which the range of operating conditions for performing the ignition timing control is determined according to the engine speed and load, depending on the cooling water temperature. Ignition timing control device for internal combustion engines. 4. Claim 3, characterized in that the table determining the range of operating conditions in which the ignition timing control is performed has a wider range of operating conditions in which the ignition timing control is not performed as the table for lower cooling water temperatures increases. Ignition timing control device for internal combustion engines. 5. Claim 3 or 4, characterized in that the table determining the range of operating conditions for performing the ignition timing control states that the ignition timing control is not performed under operating conditions of low rotation speed and low load. An ignition timing control device for an internal combustion engine as described in 2. 6. The determining means determines whether a starter switch is turned on during starter operation as an operating parameter of the engine, and when the starter switch is on, the ignition timing control is performed regardless of other operating parameters. An ignition timing control device for an internal combustion engine according to claim 1, characterized in that the ignition timing control device for an internal combustion engine makes a determination.