JPS62147048A - Ignition timing control device for engine - Google Patents

Abstract

PURPOSE:To improve the acceleration response and prevent the generation of hesitation, by correcting a blunting amount for controllably suppressing a rapid change in load signal or ignition advance signal at acceleration according to a value of an accelerated condition signal. CONSTITUTION:A control unit 14 is provided to read a throttle valve opening from a throttle valve opening sensor 15 and compute a change in time between the present throttle valve opening and the previous throttle valve opening. Then, a blunting correction factor is read from a blunting correction table stored in ROM, and using this blunting correction factor, a blunting amount of a suction air quantity from an air flow meter 2 is corrected. Then, using the suction air quantity blunted and an engine speed from a crank angle sensor 16, a map of a fundamental ignition advance stored in the ROM is read to obtain a final advance angle, then executing the advancing.

Description

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

(Prior Art) Conventionally, as disclosed in, for example, Japanese Patent Application Laid-open No. 59-147871, engine speed and engine speed have been
An ignition advance angle map that corresponds to the engine load generated by the amount of intake air per rotation is stored in the ROM,
Current engine speed Ne from the output of the crank angle sensor
The engine ignition timing control device detects the engine load from the intake air amount Qa detected by the air flow meter, reads the ignition advance angle θ from the map written in the ROM, and controls the ignition timing. is proposed.

However, as shown in FIG. 6, as the throttle opening TVO increases during engine acceleration, the intake air i Q a , that is, the output of the air flow meter representing the engine load, shows an overshoot state, and such intake air In response to a severe increase in air 1QaO, the responsiveness of fuel injection is delayed and the air-fuel ratio temporarily becomes lean, so if the ignition timing is controlled based on the ignition advance map described above, over-advancement occurs. This caused the problem of knocking.

Therefore, in the past, so-called "smoothing control" was performed to suppress the overshoot of the intake air lQa, that is, the output of the airflow meter that represents the engine load, as shown by the broken line in Figure 6, to prevent over-advancement of the ignition timing. This prevents the occurrence of noaking.

By the way, in the above-mentioned "smoothing control", for example, the intake air lQa is rounded using equation (1) shown below, the ignition advance angle map is read using the rounded value Qa', and the desired value is calculated. The ignition advance angle θ is obtained.

〜－－－－－－－－－・ (1) Here, N is a raw constant, Qa,, -+ is the output value of the air flow meter at the previous processing time Lx-+, Qa
, , is the output value of the air flow meter at the current processing time t7, and Qan is the output value of Qa, , which has a smaller value than this.
' indicates that he was fooled.

Conventionally, smoothing control has been performed by setting the smoothing constant N to a constant value that corresponds to the requirements during rapid acceleration, which inevitably has severe conditions for noaking.

However, as mentioned above, if the smoothing constant N is set in response to the demands during rapid acceleration, the smoothing amount will be too large for the demands during slow acceleration, and as a result, the ignition timing will be relatively delayed. This had the disadvantage of deteriorating acceleration response and causing hesitation.

(Objective of the Invention) Therefore, an object of the present invention is to provide an ignition timing control device that can appropriately control the ignition timing both during rapid acceleration and during slow acceleration.

(Structure of the Invention) The ignition timing control 2r according to the present invention is a smoothing control means for suppressing a sudden change in a load signal or a signal representing an ignition advance angle during engine acceleration with a smoothing effect corresponding to this change. and means for detecting the acceleration state of the engine and generating an acceleration state signal, and smoothing amount correction means for correcting the smoothing amount according to the value of the acceleration state signal. .

(Effects of the Invention) According to the present invention, since the ignition timing can be obtained in accordance with the acceleration state of the engine, the acceleration response can be improved and the occurrence of hesitation can be prevented.

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

FIG. 1 shows a schematic diagram of a fuel injection type engine equipped with an ignition timing control device according to the present invention, l is an intake passage of an engine E, and this intake passage l is equipped with an air flow meter 2 for detecting intake air iQa. , the downstream throttle valve 3
and is provided.

When the intake valve 4 is opened, the air introduced into the intake passage 1 is mixed with fuel injected from the fuel injection valve 5, introduced into the combustion chamber 7 from the intake port 6, compressed, and ignited. It is ignited by plug 8.

On the other hand, exhaust gas is discharged from the exhaust boat 10 into the exhaust passage 11 by opening the exhaust valve 9, purified by the catalytic converter 12, and discharged into the atmosphere. 13 is an air-fuel ratio sensor, 14 is a control unit consisting of a microcomputer, and this control unit 14 is
The output of the air flow meter 2 that detects the intake air lQa, the output of the throttle valve opening sensor 15 that detects the opening TVO of the throttle valve 3, the output of the air-fuel ratio sensor 13, and the crank angle that detects the engine speed Ne. The fuel injection pulse width is calculated based on the output of the sensor 16, etc., and fuel injection by the fuel injection valve 5 is controlled. The ROM of the control unit 14 also contains the engine speed Ne.
A map of the basic ignition advance angle θ, E, a smoothing constant N, a smoothing correction coefficient table, an ignition timing control program, etc. determined in accordance with the intake air jlQa per engine rotation are stored in advance. The timing of the ignition pulse sent from the ignition coil 17 to the ignition plug 8 is controlled.

In the above configuration, the control unit 14
A lead angle value determination routine is executed according to a flowchart, an example of which is shown in the figure.

First, perform initial settings in step 21, then step 2.
2, read the intake air iQa, engine speed Ne, and throttle valve opening] ゛V○. As shown in FIG. 3, from the throttle valve opening TVO, -+ at -1 since the previous processing time and the current throttle valve opening TVO, the throttle valve opening during time dt is calculated. Change dTVO=TVo11-TVO1-
1 is calculated in step 23. Next, in step 24, the smoothing correction coefficient K is read out from the rounding correction table as shown in FIG. ) The smoothing of the intake air amount Qa is corrected according to the equation, and the smoothed values Qa, , ' are obtained.

---- (2) Then, in the next step 26, Q calculated using the above formula (2)
Using a,,' and the engine speed Ne read in step 22, the basic ignition advance angle θlAs! stored in the ROM is determined. The final lead angle value is obtained by reading the map, and the lead angle is executed in step 27.

In the advance angle value determination routine shown in the flowchart of FIG.
However, instead of performing the smoothing control on the intake air 11Qa and the correction control of the smoothed amount, for example, as shown in the flowchart of FIG. 5, the basic ignition Advance angle θIIASE
Annealing control for the advance angle value θ read from the map and correction control for the amount of annealing may be performed. In that case, after calculating the degree of change in the throttle valve opening TVO in step 23 of FIG. 5, ' is determined as a correction coefficient for the rounding amount of the advance value θ in step 24',
In step 25', a map of the basic ignition advance angle θIIAIE is read using the intake air amount Qa and engine speed Ne read in step 22, the advance value θ is read out, and the advance value obtained in step 24' is read. Step 26'
The final lead angle value is obtained by calculation in step 27', and the lead angle is executed in step 27'.

In addition, smoothing control is performed on the intake air fiQa,
Using the rounded intake air lQa' and engine speed Ne, read the map of the basic ignition advance angle θ8ASE, read the lead angle value, and then correct the rounded star for this lead angle value. You may do so.

As is clear from the above explanation, according to the present invention, since the smoothing control is performed by changing the value of the smoothing correction coefficient depending on the acceleration state during acceleration, both during sudden acceleration and slow acceleration. The optimum advance angle value can be obtained in this way, making it possible to prevent engine knocking and improve acceleration response.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an engine equipped with an ignition timing control device according to the present invention, FIG. 2 is a flowchart showing an example of an advance angle determination routine in the ignition timing control device, and FIG. 3 is a throttle valve opening during acceleration. Figure 4 is a graph showing the relationship between the degree of change in throttle valve opening and the smoothing correction coefficient. Figure 5 is a flowchart showing another example of the advance angle determination routine. FIG. 6 is a graph illustrating smoothing control for the amount of intake air during acceleration in a conventional ignition timing control device. 1-Intake passage, 2-Air flow meter 3-Throttle valve 5-Fuel injection valve 8-Spark plug
13--Air-fuel ratio sensor 14--Control unit 15-Throttle valve opening sensor 16 Crank angle sensor 17-Ignition coil

Claims (1)

[Claims] From an engine rotation speed signal output from an engine rotation speed detection means and a load signal output from a load detection means that detects an engine load based on detection of intake air amount,
In an engine ignition timing control device configured to control ignition timing by determining an ignition advance angle corresponding to engine speed and engine load, the load signal or the signal representing the ignition advance angle during acceleration of the engine; a smoothing control means for suppressing a sudden change in speed with a smoothing amount corresponding to the change; a means for detecting an acceleration state of the engine and generating an acceleration state signal; An ignition timing control device for an engine, comprising means for correcting the smoothing amount.