JPH10184517A - Ignition timing control method of vehicular engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optimal final ignition timing corresponding to various operating condition precisely by correcting a fundamental ignition timing on the basis of both detected value of an intake air temperature and a cooling water temperature of an engine. SOLUTION: An intake air rate is read by an air flow meter while reading engine speed by an output signal from a crank angle sensor 67, inlet pipe negative pressure is converted into an electric signal by a pressure sensor 73, and the electric signal is inputted to a CPU 78b bypassing an A/D converter 78k. A reference ignition timing is decided according to an engine load to be calculated in the CPU 78b. An intake air temperature is detected by an intake temperature sensor 39 arranged on an air cleaner, a cooling water temperature is detected by a cooling water temperature sensor 66 arranged on an engine block, on the basis of an interpolation map which are set by a two dimensional table serving both of intake air temperature and the cooling water temperature as a parameter, collection adapted to an environmental condition in the reference ignition timing is carried out, a correction ignition timing is found out, and the reference ignition timing is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an ignition timing of a vehicle engine in which a basic ignition timing is determined from a reference set value given in advance according to the operating state of the engine and the ignition timing is controlled using the basic ignition timing as a control reference. About.

[0002]

2. Description of the Related Art In an electronic ignition timing control system for a vehicle engine, the ignition timing is basically set by an engine speed Ne and an engine load (intake air amount Q, intake pipe negative pressure P).
m, represented by a basic fuel injection pulse Tp) based on an ignition timing map of an advance angle corresponding to a function of the ignition timing map.
Normally, in a state where the intake air temperature is high, knocking is likely to occur due to abnormal combustion, and this tendency becomes remarkable in conjunction with an increase in engine cooling water temperature, so that the ignition timing is corrected and the ignition timing is delayed. Is done.

Further, in order to always improve the engine output performance and improve the fuel economy by always optimally controlling the ignition timing, knock control or the like for performing ignition at a position very close to the knock limit is performed. As described above, simply using the ignition timing map using the engine speed Ne and the engine load as parameters is not sufficient for optimal control of the ignition timing.

The ignition timing control device disclosed in Japanese Patent Application Laid-Open No. Sho 60-190668 detects an engine speed, an engine load, an intake air temperature and a cooling water temperature of an engine, and all the detected values exceed predetermined values. When the signal is output, the correction coefficient F of the basic injection pulse Tp of the fuel related to the intake air temperature
Is largely corrected, and the ignition timing is controlled based on the correction to provide a sufficient margin for the knock limit at a high temperature. That is, the basic fuel injection correction coefficient F is obtained by reading the intake air temperature, and the basic fuel injection pulse Tp expressed as the engine load is calculated. Next, the throttle valve opening exceeds 70 °, the cooling water temperature rises to 100 ° C. or more, the engine speed Ne exceeds a predetermined value, and the intake air temperature rises to 30 ° C. or more, and the correction coefficient F becomes zero. If the value is smaller than 98, the ignition timing is corrected to the retard side to avoid knocking.

[0005]

In the case of the ignition timing control device disclosed in the above publication, the temperature of the engine cooling water is 100 ° C.
When the intake air temperature rises to more than 110 ° C. above 30 ° C. and rises above 40 ° C. above 30 ° C., the ignition timing is further controlled to be retarded. In other words, the correction control is performed by considering the rising fluctuation of the intake air temperature and the engine cooling water temperature to be proportional or always the same.

However, as in the case of traveling uphill on a mountain road, the intake air temperature is low due to a decrease in the outside air temperature due to the mountainous area. May rise to a high temperature. Further, as in the case of traffic congestion on an expressway, the temperature of the intake air is substantially unchanged, but the temperature of the cooling water may decrease. In such a case, knocking occurs more frequently when the temperature of the cooling water of the other engine is high even if the temperature of one intake air is low. That is, as in the case of the ignition timing control device described in the above publication, if the correction control is uniformly performed by considering the fluctuations of the cold intake air temperature and the cooling water temperature to be proportional or in the same direction, it is difficult to perform the uphill running on a mountain road. There is a possibility that it is difficult to find the optimum ignition timing corresponding to the environmental temperature under various operating conditions such as during a traffic jam and the like.

Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to appropriately adjust the basic ignition timing determined according to the engine speed and the engine load in various operating conditions. Correspondingly, it is an object of the present invention to provide an ignition timing control method capable of obtaining an optimal final ignition timing, effective in avoiding knocking, improving engine output performance, and the like.

[0008]

According to a first aspect of the present invention, there is provided a method for controlling ignition timing of a vehicle engine according to the present invention. After obtaining the basic ignition timing, the basic ignition timing is corrected based on the detected values of both the intake air temperature and the engine coolant temperature. Therefore, it is possible to solve the problem caused by individually correcting the intake air temperature and the cooling water temperature as in the related art, thereby correcting the basic ignition timing more accurately under all environmental temperatures. Control can be performed, which is effective in avoiding knocking and improving output.

According to a second aspect of the present invention, there is provided a method for controlling an ignition timing of a vehicle engine according to a second aspect of the present invention, wherein a basic ignition timing is corrected based on a two-dimensional interpolation map of the intake air temperature and the cooling water temperature. It is to be corrected by the value. Therefore, the correction value can be quickly and reliably obtained, and the accuracy of the control is improved.

According to a third aspect of the present invention, there is provided a method for controlling ignition timing of a vehicle engine, the method comprising detecting whether or not the operating state of the engine is in a transient state, and performing the correction when the operating state is in a transient state. Is going. That is, efficient ignition timing control is achieved by performing correction using the correction value based on the two-dimensional interpolation map only in a transient state in which the difference between the intake air temperature and the cooling water temperature is relatively likely to occur.

According to a fourth aspect of the present invention, in the vehicle engine ignition timing control method, a two-dimensional interpolation map of the intake air temperature and the cooling water temperature is a matrix having, for example, 8 × 8 grid points. It consists of. Therefore, with a matrix having a large number of grid points, more accurate and quick interpolation calculation can be performed according to various operating states of the engine.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an overall configuration of a vehicle engine to which a vehicle engine ignition timing control method according to the present invention is applied, and FIG. 2 shows a block diagram of a control system. Horizontally opposed engine body 1
0 communicates with the intake passage 12 and the exhaust passage 14.
An intake chamber 16 opens to the front of the vehicle body (not shown) upstream of the intake passage 12, and an intake pipe 22 branched from a surge tank 20 communicates with the downstream side of the intake passage 12 so as to correspond to each cylinder 18. The downstream end of each intake pipe 22 communicates with each combustion chamber 26 via an intake port 24. Further, a downstream side of the exhaust passage 14 is connected to a muffler 28 attached to a rear portion of the vehicle body, and an exhaust pipe 32 communicates with each combustion chamber 26 via each exhaust port 30 at an upstream side of the exhaust passage 14.

In the intake passage 12, an air cleaner 34 for removing foreign matters such as dust in the air, an air flow meter 36 for detecting an intake air amount Q, and a throttle valve 38 are provided in order from the upstream side. The air cleaner 34 is provided with an intake air temperature sensor 39 for detecting the intake air temperature Ta. The throttle valve 38 is provided with a throttle valve opening sensor 76 for controlling the intake air amount Q according to the depression amount of an accelerator pedal (not shown) and detecting the throttle valve opening. Further, in the middle of an idle speed control (hereinafter simply referred to as ISC) passage 40 provided in the intake passage 12 bypassing the throttle valve 38, an ISC valve 42 for adjusting the intake air amount Q at idling is provided. Installed. The opening and closing of the ISC valve 42 is adjusted by the duty ratio.

On each downstream side of the intake pipe 22, an injector 44 is arranged to face the intake port 24, and the fuel pump 46 is provided by each of the injectors 44.
The fuel supplied under pressure through the fuel pipe 48 is atomized and injected. As shown, in the present embodiment, the suction pipe 22 is located immediately upstream of the intake port 24.
An injector 44 is arranged for each cylinder 18.

On the other hand, in the exhaust passage 14, a catalyst 50 such as a three-way catalyst is interposed near the engine body 10, and an air-fuel ratio sensor for detecting the air-fuel ratio in the exhaust gas is provided upstream of the catalyst 50. O2 sensor 52 is disposed.

An exhaust gas recirculation (EGR) passage 54 that communicates the intake pipe 22 and the exhaust pipe 32 is provided.
2 is formed with a smaller flow path area than any of the two. In the middle of the EGR passage 54, for example, an EGR valve 56 that is driven by a stepping motor is mounted.

The cylinder head 58 has a combustion chamber 2
6, a spark plug 60 is provided. The ignition plug 60 is driven by the high voltage supplied through the igniter 62 and the ignition coil 64 to cause the combustion chamber 26
Forcibly ignite the air-fuel mixture inside at a predetermined ignition timing.

On the other hand, in addition to the detection sensors, the engine block 57 has a cooling water temperature sensor 66 for detecting the temperature Tw of the cooling water, a crank angle sensor 67 for detecting the crank angle and the engine speed Ne, and an engine body. Knock sensor 68 for detecting knocking of camshaft 10 and camshaft 7
4, a cam angle sensor 72 for detecting the rotation angle, and a pressure sensor 73 for the surge tank 20 are arranged.

Further, the vehicle engine is provided with an electronic control unit (hereinafter simply referred to as ECU) 78 which receives detection signals from the sensors and performs electronic comprehensive control of various operations.

As shown in FIG. 2, the ECU 78 has an I / O interface 78a including an input interface to which detection signals are input from each sensor and an output interface to send a controlled drive signal to each section of the engine. Is provided. In addition, C as a main operation unit
There are provided a PU 78b, a ROM 78c in which a control program and preset fixed data are stored, and a RAM 78d in which data obtained by processing detection signals and the like from each sensor and data processed by the CPU 78b are temporarily stored.

The above-mentioned CPU 78b and ROM 78
c, a RAM 78d, and a microcomputer system having a backup RAM 78f that retains data by being supplied with power even when the ignition switch 78e is OFF, and a timer 78g and the like are interconnected by a bus line 78h. In addition, a power supply circuit 78i, an A / D converter 78k, a drive circuit 78l, and the like are incorporated.

Here, in the CPU 78b, a ROM
An output value based on a detection signal from each sensor is read via an A / D converter 78k by a program stored in a memory 78c and temporarily stored in a RAM 78d.
The basic ignition timing STD is calculated based on the data stored in the memory 78d and the fixed data stored in the ROM 78c. The basic ignition timing STD is corrected by the correction ignition timing SPKTA, and the final ignition timing ADV
The calculation of S is performed. Then, an ignition drive signal is transmitted at a predetermined timing to start energization (dwell rise), and control is performed such that dwell fall is performed and ignition is performed at the timing of the final ignition timing ADVS.

The following equation shows an example of an arithmetic expression for obtaining the final ignition timing ADVS. ADVS = STD + SPKTA + ADVSAG + DLTADV + DLTADVC (1) In the above equation (1), STD is the basic ignition timing, and the engine speed Ne and the intake air amount Q are used as parameters. can get. SPKTA is a corrected ignition timing, which is obtained by using both the engine intake air temperature Ta (° C.) and the cooling water temperature Tw (° C.) as parameters.

ADVSAG is for idling stabilization correction, DLTADV is for acceleration ignition timing correction, DLTADV
C indicates deceleration ignition timing correction. These three corrections are performed incidentally according to the engine operating state.

The corrected ignition timing SPKTA is determined by the latest intake air temperature T read via the A / D converter 78k.
a and the cooling water temperature Tw are quickly obtained on the basis of a map set by a two-dimensional table having parameters as data. Therefore, the intake air temperature Ta and the cooling water temperature Tw
Under various environmental conditions where a shift in the change occurs, the basic ignition timing STD is appropriately corrected, and the optimal final ignition timing ADVS is calculated.

Next, a method for controlling the ignition timing of the vehicle engine according to the first embodiment having the above-described configuration will be described with reference to the operation flowchart of FIG. First, this calculation flow is started by a timer interrupt, and in step (hereinafter simply referred to as “S”) 101, the engine speed Ne is read based on an output signal from a crank angle sensor 67 for generating a reference signal for ignition timing, and The intake air amount Q is read by the air flow meter 36.
The suction pipe negative pressure Pm is converted into an electric signal by the pressure sensor 73 and input to the CPU 78b through the A / D converter 78k. The ROM 78c stores a table of advance angles corresponding to the engine speed Ne and the intake air amount Q. The CPU 78b calculates an engine load Tp (Tp = Q / Ne) represented by a basic pulse width, which is a fuel injection amount corresponding to the current engine operation state.

That is, the CPU 78b converts the engine speed Ne from the crank angle sensor 67 and the intake air amount Q from the air flow meter 36 into digital data by the A / D converter 78k based on the program stored in the ROM 78c. It is temporarily stored in the RAM 78d.

The data stored in the RAM 78d,
The basic ignition timing STD corresponding to the engine load Tp is determined based on fixed data by a program stored in the ROM 78c. That is, the basic ignition timing STD
The engine speed Ne and the intake air amount Q, which are reference set values for determining the engine speed, are used as parameters. The basic ignition timing STD is obtained by searching based on the map of the two-dimensional table based on these two parameters. When the advance angle is obtained, an ignition signal is sent to the igniter 62 at the ignition timing.

Under normal operating conditions, the basic ignition timing S
The TD is obtained by interpolation from a map having a required number of matrices composed of the engine speed Ne and the engine load Tp.

Next, in S102, the intake air temperature Ta is detected by the intake air temperature sensor 39 provided in the air cleaner 34.
Is detected, and the cooling water temperature Tw is detected by the cooling water temperature sensor 66 provided in the engine block 57 in S103. The intake air temperature Ta and the cooling water temperature Tw are A /
The data is temporarily stored in the RAM 78d as intake air temperature detection data and cooling water temperature detection data via the D converter 78k.

Next, in S104, based on an interpolation map set by a two-dimensional table using both the detected intake air temperature Ta and the cooling water temperature Tw as parameters, a correction suitable for environmental conditions is made for the basic ignition timing STD. Then, the corrected ignition timing SPKTA is obtained.

Then, in S105, as shown in the above-mentioned calculation (1), the basic ignition timing STD determined in S101 is corrected by the corrected ignition timing SPKTA calculated in S104. . And S
At 106, the final ignition timing ADVS is determined. In the present embodiment, three corrections, i.e., the idle stabilization correction ADVSAG, the acceleration ignition timing correction DLTADV, and the deceleration ignition timing correction DLTADVC, are performed as ancillary operations using a one-dimensional table different from the two-dimensional interpolation map in S106. Done. For example, the ignition timing is slightly retarded during acceleration, and the ignition timing is advanced during deceleration.

Next, at S107, the basic ignition timing SVS is calculated based on the final ignition timing ADVS calculated at S106.
The energization time corresponding to the dwell angle is controlled by TD.
That is, the basic ignition timing STD or the final ignition timing A
The energization is started (dwell rising) at a predetermined timing by the DVS, and the dwell is lowered at a predetermined timing to ignite the ignition.

As described above, in the present embodiment, the basic ignition timing S determined by the map corresponding to the engine speed Ne and the intake air amount Q expressed as the engine load.
TD, the intake air temperature Ta and the engine coolant temperature T
The correction is performed using a two-dimensional interpolation map with w. Therefore, for example, when climbing up a hill on a mountain road where the intake air temperature Ta becomes low due to a decrease in the outside air temperature, the cooling water temperature Tw becomes high and knocking is effectively prevented. That is, since both the intake air temperature Ta and the cooling water temperature Tw are managed at the same time, it is effective to find the optimum ignition timing corresponding to any environmental temperature.

In the above-described embodiment, when the final ignition timing ADVS is obtained, correction is basically performed based on the two-dimensional interpolation map based on the latest intake air temperature Ta and cooling water temperature Tw. As described below, another embodiment in which a condition is additionally set and correction is performed only when the condition is satisfied is also possible.

For example, as shown in FIG. 4, as another additional condition, it is determined whether or not the operation state of the engine is in a transient state (for example, an acceleration state or a deceleration state). In this determination, the preceding and following steps are not displayed in FIG.
It is performed between 103 and S104, that is, before calculating and applying the correction value. Then, Y determined to be in the transient state
Only when es is set, the ignition timing correction operation is performed.
In this case, this operation is not performed. This is because, in a transient state in which the operating state of the engine is largely fluctuated, the difference between the intake air temperature Ta and the cooling water temperature Tw is likely to occur. The correction of the embodiment is performed.

FIG. 5 shows an example in which another condition is added. That is, the intake air temperature Ta and the cooling water temperature Tw
Is determined to exceed a predetermined intake air temperature α, which is a preset correction execution temperature of intake air, and a predetermined cooling water temperature β, which is a correction execution temperature of engine cooling water.
This step is performed before the ignition timing correction operation after S104 as in the example of FIG.

That is, in S201, the CPU 78b compares the intake air temperature Ta temporarily stored in the RAM 78d as intake temperature detection data with the predetermined intake temperature α stored in the ROM 78c. If it is determined that the temperature does not exceed the predetermined intake air temperature α (No), S2
02, and if it is determined that the temperature exceeds the predetermined intake air temperature α (Yes), the process proceeds to S104 (FIG. 3).

In S202, the CPU 78b controls the RAM 7
A comparison is made between the cooling water temperature Tw temporarily stored as cooling water temperature detection data in 8d and a predetermined cooling water temperature β which is a correction execution temperature stored in the ROM 78c. When it is determined that the temperature does not exceed the predetermined cooling water temperature β (No), the routine is returned to perform a normal (not the control according to the present invention) ignition timing control operation, and the temperature exceeds the predetermined cooling water temperature β (Yes). ), The process proceeds to S104. Therefore, if at least one of the values exceeds the predetermined value in S201 and S202, the ignition timing correction in S104 and thereafter is performed. Thus, the correction is performed only in a high temperature state equal to or higher than a predetermined temperature at which knocking is likely to occur, and control efficiency is improved.

Here, in any of the above embodiments, the two-dimensional interpolation map of the intake air temperature Ta and the cooling water temperature Tw can be constituted by a matrix having, for example, 8 × 8 grid points. Interpolation can be performed according to various operating states of the engine by a large number of options.

[0041]

As described above, according to the ignition timing control method for a vehicle engine according to the present invention, the intake air temperature and the basic ignition timing determined according to the engine speed and the engine load are controlled. By correcting the ignition timing based on both the detected data of the engine coolant temperature, highly accurate ignition timing correction control can be performed under various environmental temperatures, and knocking can be avoided and output can be improved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an automobile engine to which an ignition timing control method according to the present invention is applied.

FIG. 2 is a block diagram showing a control system circuit used in the embodiment.

FIG. 3 is a calculation flowchart showing the operation of the embodiment.

FIG. 4 is a calculation flowchart showing the operation of the embodiment to which other conditions are added.

FIG. 5 is a flowchart illustrating the operation of the embodiment in which other conditions are added.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Engine main body 16 ... Crank angle sensor 24 ... Spark plug 26 ... Intake valve 28 ... Exhaust valve 39 ... Intake temperature sensor 44 ... Injector 78 ... Electronic control unit (ECU) 66 ... Cooling water temperature sensor

Claims (5)

[Claims] 1. An ignition timing control method for a vehicle engine, wherein a basic ignition timing is obtained based on data obtained according to an operation state of the engine, and the ignition timing is controlled based on the basic ignition timing. A vehicle engine ignition timing control method, wherein the correction is made based on both the detected values of the engine coolant temperature and the engine coolant temperature. 2. The method according to claim 1, wherein the correction is performed based on a correction value obtained based on a two-dimensional interpolation map of the intake air temperature and the engine coolant temperature with respect to the basic ignition timing. 2. The ignition timing control method for a vehicle engine according to claim 1. 3. The method according to claim 1, wherein the correction is performed when the operating state of the engine is in a transient state and the correction is performed when the operating state is in a transient state. An ignition timing control method for a vehicle engine. 4. The method according to claim 1, wherein the correction is performed when one of the intake air temperature and the engine coolant temperature exceeds a predetermined correction execution temperature set in advance. An ignition timing control method for a vehicle engine according to any one of the preceding claims. 5. The two-dimensional interpolation map of the intake air temperature and the cooling water temperature of the engine is constituted by a matrix having a required number of grid points.
The ignition timing control method for a vehicle engine according to any one of claims 4 to 7.