JPS62121866A - Method for controlling ignition timing for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent temporary reduction in torque, the occurrence of knocking, a misfire, etc. by varying an ignition timing so as to be correspondent to the delay in response of an intake air control valve, in a transient condition of switching over said intake air control valve. CONSTITUTION:When the switchover of the opening of an intake air swirl control valve 12 which is provided in an intake passage 3 to an engine 1 and which can close a part of the passage, is carried out in accordance with an engine load, a control unit 20 maintains a pre-switchover ignition timing suited to an allowable lead angle value corresponding to the operating condition before the switchover of the opening, until a first defined period after the switchover. After that, during the time from the first defined period to a second defined period, the ignition timing is gradually changed to a post-switchover ignition timing suited to an allowable value corresponding to the operating condition after the switchover of opening an, after the second defined period has elapsed, it is set to the post-switchover ignition timing. Thus, ignition timing is varied so as to be suited to the delay in response of the swirl valve 12, thereby, preventing temporary reduction in torque, the occurrence of knocking, a misfire, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ignition timing control method for an internal combustion engine that performs variable intake swirl.

(Prior art) Recently, there are some engines that perform intake swirl in low and medium load ranges from the perspective of improving engine output performance.
By increasing the flame speed, it is also possible to operate with a lean mixture.

As a conventional ignition timing control method for an internal combustion engine equipped with this kind of intake swirl control function, for example, Japanese Patent Laid-Open No. 58-19
There is one described in Japanese Patent No. 5048.

In this method, the amount of intake air is detected as the engine load, and in response to the increase in engine load, the opening of the intake swirl control valve (hereinafter simply referred to as the intake control valve) is increased and the air-fuel ratio of the supplied mixture is reduced. At the same time, the ignition timing advance value is set in accordance with the allowable advance value, which changes depending on the opening degree of the intake control valve. As a result, in low and medium load ranges, the intake control valve closes and creates an intake swirl to efficiently burn a lean mixture, while in high load ranges, the intake control valve opens and reduces charging efficiency. At the same time, the ignition timing is advanced to compensate for the decrease in combustion speed, and the combustion state is appropriately controlled.

(Problems to be Solved by the Invention) However, in such a conventional ignition timing control method for an internal combustion engine, it is difficult to
Since the structure was such that the selection control of the intake control valve between fully closed and fully open, control of the supply air-fuel ratio, and control of the ignition timing were performed simultaneously based on If the time required to switch the corresponding ignition timing is different from the time required to fully open the intake control valve, intake control may be performed under transient conditions where the opening of the intake control valve changes, albeit temporarily. A situation arises in which the engine is operated at an air-fuel ratio that does not match the opening degree of the valve and at the time of ignition. In such a case, problems such as a temporary decrease in torque, occurrence of knocking, and misfire occur under transient conditions.

As mentioned above, such a problem occurs when the switching times of the three are different. Here, switching between the three is generally performed by negative pressure switching, in which the negative pressure applied to the diaphragm is selectively switched to atmospheric pressure or suction negative pressure using a negative pressure switching control valve. If the switching time constants of the systems differ, the switching times will be different.

In addition, the supplied air-fuel ratio (supplied fuel amount) and ignition timing are set according to the intake air amount and engine rotation speed, not limited to the above example, but for example, in an engine that performs electronically controlled fuel injection (EGi). However, when a diaphragm actuator and an intake control valve that is driven and controlled by a negative pressure switching control valve are combined, the switching time constant of the intake control valve becomes larger than that of the former two, resulting in a response delay. , a similar problem has been pointed out.

<Purpose of the Invention> Therefore, the present invention aims to optimize the ignition timing under transient conditions in which the opening of the intake control valve changes regardless of the difference in the switching time constants of the three above, thereby preventing a temporary decrease in torque. The purpose is to improve drivability by preventing knocking and misfires.

(Structure of the Invention) In order to achieve the above object, the ignition timing control method for an internal combustion engine according to the present invention, as shown in the basic conceptual diagram in FIG. When the opening degree of the intake vortex control valve, which can partially block the valve, is changed according to the engine load, b) The ignition time corresponds to the operating conditions before the opening degree change until the first predetermined period after turning off +1A. C) From this first predetermined period to the second predetermined period, the ignition timing is maintained at a pre-switching ignition timing corresponding to the allowable advance value, and C) the ignition timing is maintained at the allowable advance value corresponding to the operating condition after opening degree switching d) When the second predetermined period has elapsed, the ignition timing is set to the ignition time after switching.

(Function) In the present invention, when the opening degree of the intake control I valve is changed,
In response to this switching timing, the ignition timing is set to the value before switching (the value assuming no switching) until the first predetermined period, and then gradually changes until the second predetermined period. After the second predetermined engine period has elapsed, it is set to a value corresponding to the operating condition after switching the opening degree. As a result, the switching time constants of intake control and ignition timing control match. Therefore, even under the transient conditions of switching the opening of the intake control valve, the ignition timing is appropriate, and it is possible to prevent a temporary decrease in torque, occurrence of knocking, misfire, etc.

(Example) Hereinafter, the present invention will be explained based on the drawings.

FIG. 2.3 is a diagram showing an embodiment of an engine combustion control device using the ignition timing control method according to the present invention.

First, the configuration will be explained. In FIG. 2, reference numeral 1 denotes an engine, in which intake air is supplied from an air cleaner 2 to each cylinder through an intake pipe 3, and fuel is injected by an injector 4 based on an injection signal Si. 5 spark plugs for each cylinder
is installed, and the spark plug 5 is equipped with a high pressure generating unit 7.
A high voltage pulse Pi is supplied from the port 6. The high voltage unit 6 generates a high voltage pulse Pi based on the ignition signal Sp.

Then, the air-fuel mixture in the cylinder is ignited and exploded by the discharge of the high-pressure pulse Pi, and is introduced into the catalytic converter 8 through the exhaust pipe 7 as exhaust gas. .

X) is purified by a three-way catalyst and discharged.

The intake air flow rate Qa is measured using a flap type air flow meter 9.
and is controlled by a throttle valve lO in the intake pipe 3. The opening degree θ of the throttle valve 10 is detected by a throttle valve opening sensor 11 . Further, a swirl valve 12 is provided in the intake pipe 3 near the intake boat, and the swirl valve 12 opens and closes based on a control signal Sv input to a solenoid valve 14 that controls the negative pressure applied to the drive valve 13. This creates a so-called swirl from the intake port into the cylinder to improve combustion.

The rotation speed N of the engine 1 is detected by the crank angle sensor 15, and the temperature Tw of the cooling water flowing through the water jacket is detected by the crank angle sensor 15.
is detected by the water temperature sensor 16.

Further, the oxygen concentration in the exhaust gas is detected by an oxygen sensor 17, and an oxygen sensor 17 having a characteristic that its output Vs corresponds one to one with respect to a wide range of air-fuel ratios is used.

Signals from each of the sensors 9, 11, 15, 16, 17 are input to the control unit 20. The control unit 20 performs air-fuel ratio control, ignition timing control, and swirl control based on the sensor information.
It is composed of a P U 21, a ROM 22, a RAM 23, and an I10 port 24. The CPU 21 imports necessary external data from the I10 boat 24 according to the program written in the ROM 22, and also reads R
It performs arithmetic processing on necessary processing values while exchanging data with the AM 23, and outputs the processed data to the I10 boat 24 as necessary. The signals from the sensor group 9.11.15.16.17 are input to the I10 port 24, and the injection signal Si is input from the I10 port 24.
, control signal SV, and ignition signal Sp are output. ROM2
2 stores an arithmetic program for the CPU 21, and a RAM 23 stores data used in the arithmetic operations in the form of a map or the like.

Next, the action will be explained.

FIG. 2 is a flowchart showing an ignition timing control program written in the ROM 22, and this program is executed once every predetermined time.

First, the intake air lQa, the engine speed N, and the throttle valve opening Cv are read at P and ~P, respectively, and the basic injection amount Tp is calculated according to the following equation (2) at P4.

a Tp =K.

When dθ/dt>A, it is determined that it is in an acceleration state, and P7
Using dθ/dt, N, etc. as parameters, the target air-fuel ratio TLA during acceleration and the target ignition time! Set IIIADVA. On the other hand, when dθ/dt≦, it is determined that there is no acceleration state, and in P8, the steady state target air-fuel ratio TLI1 and target ignition timing ADV are set using 'rp, N, etc. as parameters. At P, the target air-fuel ratio TL set this time is stored at a predetermined address in the RAM 23 together with at least the previous molecules t and l.

Next, the PIG compares the current target air-fuel ratio TL with a predetermined value B, and when TL>B, the swirl valve 12 is fully closed (
A control signal Sv is output to cause the SCV to be fully closed (hereinafter referred to as SCV fully closed). As a result, the swirl valve 12 becomes fully closed, and a swirl is generated from the intake port into the cylinder, thereby improving combustion.

At P1□, the previous target air-fuel ratio T,... is compared with a predetermined value B, and when T,-1≦B, a full-open timer is set at PI3, and at PI4, the SCV is fully opened under the operating condition of TL>B. The target ignition time 2UIADVo that matches the allowable ignition advance value when the engine is closed is determined, and the process proceeds to PIS. P
The IS outputs an ignition signal Sp at a timing corresponding to this final target ignition timing ADV to ignite the air-fuel mixture.

Further, when TL-1>B at P12, the count value tc of the fully closed timer is compared with the first predetermined value Tc at P16.

When tC<TcI, the signal is counted in Pl4, and when the value C≧TC2, it is further counted in Pl7. After setting the target ignition timing ADVD similar to step P14 and calculating the target ignition time !IJIADVE which changes gradually according to the following equation (2) in P19, the process proceeds to PIS.

Tcz-Tel X (t C-TcI) + ADV, ・-・-・00
At the target ignition time in the ceremony! 1JIADVE was originally AD■,
, and then gradually transitions to ADV or ADV[l. The above processing can be summarized in an easy-to-understand manner as shown in Table 1 below.

(Next summer, blank space below) Table 1 As is clear from Table 1, when the intake swirl is switched in the SCV fully closed process, the ignition is activated in response to this switching timing (when tc=Q). Until the first predetermined period Tcn, the pre-switching value ADVD (the value assuming no switching) is set, and after that, from Tc to the second predetermined period Tcz, the value ADVE is set to the value ADVE that gradually changes. , and after Tc4 has elapsed, it is set to a value corresponding to the SCV full-open operating condition. Under transient conditions when the swirl valve 12, which is mechanically driven by negative pressure control, is switched, the change in the ignition timing, which is electronically advanced, is made gradual to match the switching time constants of the two. It means that. Therefore, even under the transient condition of fully closed SC, the ignition timing becomes appropriate, preventing a temporary drop in 1-lux, knocking, misfires, etc., and improves drivability. be able to.

On the other hand, when TL≦B in step PIG, a control '12 signal 3v is outputted to fully open the swirl valve 12 (hereinafter referred to as SC2 fully open) at P2o. As a result, the swirl valve 12 becomes fully open, increasing the filling efficiency. In the subsequent step Pz+%Pze, the ignition timing is changed in consideration of the switching time constant of the swirl valve 12 so as to cope with the response delay, as in the case of the SCV fully closed process.

That is, P2. Then, as in the previous step P12, the previous target air-fuel ratio TL-1 is compared with the predetermined value B, and TL-1>
When it is 8, set the full open timer with P2□ and
SCV under the operating condition of T +, ≦B at P23.
Target ignition time jI that matches the allowable advance angle value when fully opened
Determine IIADvc and proceed to P15.

Further, when TL-1≦B in Pal, the count value t0 of the full-open timer is set to the first predetermined value T in PX3. Compare with 1.

When to<TOI, the process advances to P23, and when to≧TI, I, the count value t0 is set to the second predetermined value T in PZS. Compare with 2. When to<'1'o2, a target ignition timing ADVc similar to the step pH is set in P2b, and Pg? After calculating the target ignition timing ADVF which gradually changes according to the following formula 〇, the process proceeds to PIS.

'roz-To.

X (t OTOI) + A D VC"""Target ignition time in the 00 formula!tJlADVF is initially equal to AD■, and then gradually shifts to ADVA or ADVB.The above processing is performed by SC■ As in the case of closing processing, the results can be summarized in an easy-to-understand manner as shown in Table 2 below.

(Honshin, hereafter in the margin) As is clear from Table 2, the ignition timing gradually changes when the intake swirl is switched in the SCV fully open process as well as in the fully closed process.

Therefore, as in the case of SCV fully closing processing, it is possible to appropriately change the ignition timing and prevent a decrease in torque, etc., regardless of the difference in the switching time constants between the two.

Note that in this embodiment, the first predetermined period 'rct.

Tel and the second predetermined periods Tcz and T6z may be optimally set according to the intake control and ignition timing control mechanisms, engine models, etc., and the present invention can be applied to various types such as those mentioned in the conventional examples. It is possible to apply.

(Effects) According to the present invention, since the ignition timing is changed to correspond to the response delay of the intake control valve under transient conditions when switching the intake side J:lu valve, the ignition timing is changed at the time of switching. The timing can be set appropriately, and it is possible to prevent a temporary decrease in torque, occurrence of non-king, misfire, etc., and improve engine drivability.

[Brief explanation of drawings]

Fig. 1 is a basic conceptual diagram of the present invention, Figs. 2 and 3 are diagrams showing an embodiment of an engine combustion control device using the ignition timing control method according to the present invention, and Fig. 2 is an overall configuration thereof. 3 are flowcharts showing the ignition timing control program. 1... Engine, 3... Intake pipe, 9... Air flow meter, 11... Throttle valve opening sensor, 12... Swirl Valve, 15... Crank angle sensor, 20... Control unit.

Claims (1)

[Scope of Claims] a) When the opening degree of the intake vortex control valve that is provided in the intake passage of the engine and can block a part of the intake passage is changed according to the engine load, b) After the switching, the first Until the predetermined period, the ignition timing is maintained at the pre-switching ignition timing according to the allowable advance value corresponding to the operating conditions before the opening switching, and c) from the first preselected period to the second preselected period. d) When the second predetermined period has elapsed, the ignition timing is gradually changed to the post-switch ignition timing according to the allowable advance value corresponding to the operating condition after the opening switching; A method for controlling ignition timing of an internal combustion engine, comprising: setting the ignition timing of an internal combustion engine.