JPH0192583A - Ignition timing controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent overdelayed timing or the like in an abruptly changed running condition of an engine by calculating the instant lower limit value of delayed timing amount from the lower limit value of delayed timing obtained according to the running condition and a learning value to correct said lower limit value and limiting the corrected delayed timing with said instant lower limit value. CONSTITUTION:A basic ignition timing calculating means A for calculating the basic ignition timing according to the running condition of an engine, a delayed timing lower limit value calculating means B for calculating the delayed timing lower limit value according to the running condition of engine and a delayed timing correction amount calculating means C for calculating the delayed timing correction amount according to the presence of knocking are provided. Also, a learning value renewing means D for renewing the learning value to correct said delayed timing lower limit value and a delayed timing instant lower limit value calculating means E for calculating the delayed timing instant lower limit value from the learning value and the delayed timing amount lower limit value are provided. A delayed timing correction value is limited by the delayed timing instant lower limit value by a delayed timing correction amount limiting means F and the basic ignition timing is corrected according to the limited delayed timing correction amount by an ignition timing correction means G to control the ignition timing.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an ignition timing control device for an internal combustion engine, and in particular, the lower limit of the retardation amount is determined based on the knock occurrence point for each operating range in a certain operating state of the engine. The present invention relates to an ignition timing control device for an internal combustion engine that performs learning control of ignition timing by newly determining a value and giving a learning value common to all operating ranges based on this point.

[Conventional technology]

Conventionally, an ignition timing control device with a knock control device in an electronically controlled internal combustion engine uses an electronic advance system to calculate the ignition timing corresponding to the rotation speed and engine load. When a knock occurs, the ignition timing is retarded based on the signal from the knock sensor. That is, when knocking is detected, the ignition timing is retarded by a fixed angle until knocking no longer occurs. The amount of retardation is not unlimited, and the maximum amount of retardation is determined by the engine speed and engine load, and the amount of retardation by the knock control device is set between the basic ignition timing and the ignition timing determined by the maximum amount of retardation. moving. Then, when knocking no longer occurs, the ignition timing control device advances the ignition timing, and if knocking occurs again after the advance, the ignition timing control device performs retardation correction in the same manner as described above.

[Problem that the invention seeks to solve]

However, with this conventional ignition timing control device, when dealing with a wide range of fuel octane numbers and environmental conditions, when the basic ignition timing is set under conditions where knock is least likely to occur, conversely, when knock is most likely to occur, Excessive knocking always occurs the moment the operating state of the engine shifts to an operating range where knocking occurs. This is because conventional ignition timing control devices do not retard the ignition timing unless knock occurs, and the knock control device does not operate at the moment the engine load suddenly changes, so excessive knock can occur. It happens.

In order to prevent this, as disclosed in JP-A-55-78168 and JP-A-59-103945,
There is an ignition timing control device that incorporates learning control. The ignition timing control device that has introduced this learning control has a learning value for each operating region divided into multiple regions, and stores the ignition timing at which knock occurred in that region as a learning value, and then When conditions fall within that range, ignition timing control is performed based on the learned value.

However, even in conventional ignition timing control devices that have introduced this learned value, the learned value is updated based on the basic ignition timing, and the learned value is not updated unless the operating range is reached. There is a problem in that the frequency of learning decreases, and excessive knocking still occurs when a transition is made from one operating state to another for the first time.

The present invention solves the above-mentioned conventional problems, performs learning control based on the ignition timing in a state where knocking is likely to occur in the engine, and updates the learned value throughout the engine operating range regardless of the progress of the operating state. It is an object of the present invention to provide an excellent ignition timing control device for an internal combustion engine that can prevent excessive retardation and excessive knock when the operating condition of the engine suddenly changes by performing the same operation throughout the engine.

[Means for solving problems]

The configuration of an ignition timing control device for an internal combustion engine according to the present invention that solves the above problems is shown in FIG.

The basic ignition timing calculating means calculates the basic ignition timing according to the operating state of the engine, and the retardation amount lower limit value calculating means calculates a predetermined lower limit value of the retardation amount according to the operating state of the engine. The retardation correction amount calculation means calculates the retardation correction amount depending on the presence or absence of knocking, the learning value updating means updates a learning value for correcting the retardation amount lower limit value, and the retardation amount instantaneous lower limit calculation means The retard amount instantaneous lower limit value is calculated using the retard amount lower limit value and the learned value. The retard correction amount limiting means limits the retard correction amount to the retard amount instantaneous lower limit value. The ignition timing correcting means corrects the basic ignition timing using the retardation correction amount obtained in this way to control the ignition timing.

[For production]

According to the ignition timing control device for an internal combustion engine of the present invention, a new instantaneous value of retardation amount is created using a learned value common to all operating ranges based on a predetermined lower limit value of retardation amount, and the engine Even when there is a transition from a difficult state to any operating state where no-ignition is likely to occur, the amount of retardation from the basic ignition timing is instantaneously corrected by the instantaneous lower limit value of the amount of retardation.

〔Example〕

Embodiments of the present invention will be described in detail below using the drawings.

FIG. 2 schematically shows the overall configuration of an embodiment of an ignition timing control device for an internal combustion engine according to the present invention.

In FIG. 2, 10 is the cylinder block of the engine, 12
is a knock sensor attached to the cylinder block lO. The knock sensor 12 is composed of, for example, a piezoelectric element or an electromagnetic element, and is a well-known device that converts mechanical vibrations into electrical amplitude fluctuations.

14 indicates a distributor, and this distributor 14 is provided with crank angle sensors 16 and 18. The crank angle sensor 16 is for cylinder discrimination, and if this engine has 6 cylinders, it generates one pulse every time the distributor shaft makes one revolution, that is, every two revolutions of the crankshaft (every 720” CA). The generation position is set, for example, at the top dead center of the first cylinder.The crank angle sensor 18 generates 24 pulses each time the distributor shaft rotates once, that is, it generates a pulse every 30° of the crank angle. Occur.

Electrical signals from knock sensor 12 and crank angle sensor 16.18 are fed into control circuit 20.

A signal representing the amount of intake air from an air flow meter 24 provided in an intake passage 22 of the engine is also sent to the control circuit 20. On the other hand, the control circuit 20 outputs an ignition signal to the igniter 26, and the spark current generated by the igniter 26 is distributed to the spark plugs 28 of each cylinder via the distributor 14.

The engine is usually provided with various other sensors that detect operating state parameters, and the control diagram 20 also controls the fuel injection valve 30, etc., but these are not directly related to the present invention. , all of these will be omitted in the following explanation.

The electrical signal from the air flow meter 24 is sent to an analog multiplexer (MPX) 32 via a buffer 30, selected according to instructions from the microcomputer, and applied to an A/D converter 34, where it is converted into a binary signal. After that, it is taken into the microcomputer via the input/output port 36.

Pulses for every 720 degrees of crank angle from the crank angle sensor 16 are sent to the interrupt request signal generation circuit 4 via a buffer 38.
Applied to 0. On the other hand, a pulse for each crank angle 306 from the crank angle sensor 18 is applied to an interrupt request signal generation circuit 40 and a speed signal generation circuit 44 via a buffer 42. The interrupt request signal generation circuit 40 has a crank angle of 7
Various interrupt request signals are generated from the pulses every 20" and every 30 degrees. These interrupt request signals are applied to the microcomputer via the input/output port 46. A binary signal representing the rotational speed Ne of the engine is generated from the period of the pulse every 30 degrees.This rotational speed signal is sent to the microcomputer via the input/output port 46.

The output signal of the knock sensor 12 is transmitted through a buffer for impedance conversion and a knock-specific frequency band (7 to 8 kHz).
) is the passband of the peak hold circuit 50 via a buffer filter circuit 48 consisting of a bandpass filter.
sent to. The peak hold circuit 50 takes in the output signal from the knock sensor 12 and holds the maximum amplitude only when a 1'' level signal is applied from the microcomputer via the input/output port 46 and the line 52.

A reset signal is input via input/output port 46 and line 70 to reset the maximum amplitude. The output of the peak hold circuit 50 is converted into a binary signal by the A/D converter 54 and sent to the microcomputer via the input/output port 46. However, the A/D conversion start of the A/D converter 54 is performed by an A/D conversion start signal applied from the microcomputer via the input/output port 46 and line 56. Further, when the A/D conversion is completed, the A/D converter 54 notifies the microcomputer of the completion of the A/D conversion via the line 58 and the input/output port 46.

On the other hand, when an ignition signal is output from the microcomputer to the drive circuit 60 via the input/output board 46, this is converted into a drive signal and the igniter 26 is energized, depending on the duration and duration of the ignition signal. ignition control is performed.

The microcomputer is connected to the input/output ports 36 and 4 mentioned above.
6, a microprocessor (MPU) 62, a random access memory (RAM) 64, a read-only memory (ROM) 66, and a backup random access memory (B-RA) that retains the memory contents even when the power is turned off.
M) 69, a clock generation circuit (not shown), a memory control circuit, and a bus 68 connecting these circuits, etc., and executes various processes according to a control program stored in the ROM 66.

The ROM 66 also contains a map of the basic ignition timing ABSE expressed by engine speed and engine load, and a knock limit value (1 to 3 A map of the amount of retardation by which the angle is advanced is stored in advance.

Next, the operation of the control diagram lR2O in FIG. 2 will be explained. FIG. 3 shows an interrupt routine that is executed every time the top dead center of each cylinder is 90° CA.

In step 301, first, the engine speed Ne and the engine load Q are
/N (in this embodiment, the intake air amount per engine revolution is used as the engine load).

Next, the engine speed N read in step 302
The basic ignition timing ABSE corresponding to e and engine load Q/Ne is calculated using the above-mentioned map. This basic ignition timing AB
S[! is shown using a solid line in the ignition timing-torque characteristic diagram of FIG. Then, in step 303, the retardation amount upper limit A
KC5,,, instantaneous retard amount upper limit value tAKCS, □, retard amount lower limit value AKC3,,,, and retard amount instantaneous lower limit value tA
Calculate KC5,,,. Note that AKC5,,x and AKC5+hin are stored in the ROM66 of the control circuit 20, and tAMcs□8 and tAKcslI,,l
is stored in the RAM 64.

The retardation amount upper limit value AKCS□ is the maximum retardation amount for which it is meaningless to retard the ignition timing any further. Retard amount instantaneous upper limit t
AKcs+mmx is the learning value AGK, which will be described later after engine operation.
According to C5, the following formula, tAKC3,, x = AKC30, -AGKCS
- Retard amount upper limit value AKC3- corrected using ■
8, and initially tAKC3□X =AKC3,,X, but after the institution enters the learning area even once, A
The initial value of GKCS (AGKCS used first after entering learning 6iM) is 8GKC5 which was last learned last time.

In addition, the retardation amount lower limit value AKC5,... is newly set in the present invention, and is slightly (1 to 3 degrees) lower than the knock limit value depending on the engine speed and engine load when using regular gasoline. degree) is the amount of retardation by which the angle is advanced. This retard amount instantaneous lower limit value tAKC3,i.

is the instantaneous retard amount upper limit tAKC3, □Similarly, the following formula,
tAKCS□, = AXC3,i,l-AGKCS
... Retard amount lower limit value A corrected by learning using ■
KC30, and the retard amount instantaneous upper limit value tAKC5,
, X, initially tAKCSmi-=AKC5*t, l
However, once an institution has entered the learning area,
The initial value of AGKCS (AGKCS used first after entering the learning area) is the AGKCS learned last time.

Upon completion of step 303, the process proceeds to step 304, where it is determined whether the AKC3,,n value is a positive value or a negative value. If the value of AKC3,..., is a positive value (YES), proceed to step 306, but if the value of AKC5,... is a negative value (<NO), proceed to step 305, and set the value of AKC3,i to O. return. This is because the basic ignition timing ABSE is the maximum torque point, so it is useless to advance it by more than this value, so the lower limit value is set to O.

In step 307, Ne read in step 301.

tABSE is determined from Q/N, ABSE is corrected in step 308 using the following equation, and the process proceeds to step 309.

ABSE 4-tABSE-AXCS step 30
8, the knock control retard amount AKC5 is updated. Details of this update are shown in FIG.

This update is executed every 120° CA (Top Dead Center TIIC).

The occurrence of knock is determined when knock occurs between the top dead center TDC of a stroke of a certain cylinder and the next top dead center TDC (step 401), and only when knock occurs (YES). In step 402, the knock control retard amount AKC3 is retarded by the angle α (CA). After performing retard processing in step 402, the count value of the counter is cleared in step 403, and the process returns. This knock control retardation amount AKC
The update of 3 is also carried out every predetermined time period when no knock occurs.

At this time, it is determined in step 404 whether the counted value of the counter exceeds a predetermined time, for example, 0.4 seconds, and after the predetermined time has elapsed, the knock control retard amount AKC5 is determined as shown in step 405. is the angle β(CA)
advance only.

Then, the process returns from step 406.

In step 309, the knock control retard amount AKCS updated as described above is guarded by the instantaneous retard amount upper limit value tAKcs, , x calculated in step 303 and the retard amount instantaneous lower limit value tAKCSmt-. The control retard amount AKC3 is set to a value within this range. As mentioned above, at the initial stage after the start of engine operation, when learning control has not yet been performed, tAKcs,,K
=AKCS, , and tAKC3,,ゎ=AKC3,
,.

Therefore, the knock control retardation amount AKC5 is the retardation amount upper limit value AXC3, , and the retardation amount lower limit value AKCS@,
, is first guarded by .

Step 310 is to update the learned value AGKCS for correcting the upper and lower limits of the retard amount, and the details thereof are shown in FIG. Note that the learning value AGKC5 is the control circuit 20
is stored in the B-RAM 69 of.

Steps 501 and 502 are for determining whether the operating state of the engine is in the knock control learning control execution region. When the engine rotational speed Ne is within the range of the predetermined rotational speed In this case, it is assumed that the knock control is in the learning control execution area, and the process proceeds to step 503. Otherwise, in step 507, the academic H value AGKC5 is guarded with 0-AGKC5, .

In the following step 503, the knock control retardation amount AK is
Compare C3 with the instantaneous lower limit value of retardation amount tAKC5,..., and if the difference is smaller than a (for example, 2 to 4" CA), then (YE
S) Proceed to step 504 and add p (for example, 0.1 to 1" CA) to the learning value AGKC5. As a result, the range tAKCS, f of the knock control retard amount ^KC3
f1ll~tAKCS□8 moves by p to the advance angle side.

In step 505, the knock control retardation amount AKC5 is
is compared with the retard amount instantaneous lower limit value tAKC3-i-, and when the difference is greater than b (for example, 4 to 6' CA) (YES), the process proceeds to step 506, and q (for example, 0
．． 1 to 1"CA). As a result, the knock control retard amount AKCS range tAKC3,i, to t
AKC3llll.

8 moves to the retard side by q. Step 507 is a guard for the learned value AGKC3, which is set to be in the range from 0 to AGKC3□8 (for example, 7 to 10'' CA).

With the above control, the knock control retardation amount AKC5
is always within the range of aw b on the retard side from the instantaneous lower limit value tAKC5, .

When the update of the learned value AGKC5 in step 310 is completed, the process proceeds to step 311, where the ignition timing is corrected using the formula (Assε-AKC5), and the spark plug 28 sparks at the corrected ignition timing.

Next, the operation of the ignition timing control device for an internal combustion engine according to the present invention explained above will be explained using FIG.

FIG. 6 shows the ignition timing and torque characteristics for each engine load in a certain rotation range of the engine.

When the operating state of the engine enters the learning area from outside the learning area, the basic ignition timing ABSE determined in step 308
The retardation amount AKC3 from KC5 instantly changes to the retardation amount lower limit value KC5,
The lower limit is guarded at , . Retard amount instantaneous lower limit value tAKCS
is set to the a-b advance angle side compared to AKC3 determined at the end of the previous time.

Thereafter, the retardation amount AKC3 is updated according to the occurrence of knocking, and when no knocking occurs, the retardation amount AKC3 is reduced,
When the difference from the retardation amount lower limit value AKC81,, becomes less than a,
The learning value AGKCS increases and the retardation amount lower limit value AKC3II
, moves to the advance side. When a knock occurs, the retard amount AKC5 is increased, and when the difference from the retard amount lower limit value AKC3□7 becomes more than b, the learned value AGKC3 decreases and KC3,,,, is delayed to the retard amount lower limit value. Move to the corner.

As described above, in the device of the present invention, the knock control correction value KC5 is first set to the retard amount instantaneous lower limit value tAKC5, which is set for each region in any driving region.

Retard amount instantaneous lower limit value tAKC5, .

The learning value AGKC5 is updated so as to maintain a constant relationship. The learned value GKC3 of the present invention is one value regardless of the operating range of the engine and under each condition of the engine speed Ne and the engine load Q/Ne.

Therefore, as shown in the three-dimensional map of FIG.
SI! is determined as shown by the solid line, and on the other hand, the retard amount upper limit value AKC3,,, is determined as the broken line, and the retard amount lower limit value AKC5,,, is determined as the dashed line. For example, when the fuel is changed from regular gasoline to high-octane gasoline, the shift of the retard amount instantaneous lower limit value tAKC3,,, toward the advance side in a certain driving range is calculated.
Since the learning value AGKC3 is common, the retard amount instantaneous lower limit value tA
KC3,i is shifted in a plane parallel to the retard amount lower limit value IKCS,ifi, as shown by the two-dot chain line in FIG. Therefore,
No matter how the engine is operated after changing its fuel to high-octane gasoline, the optimum ignition advance angle will be achieved in each operating range, and excessive knock will not occur.

Furthermore, when this engine stops using high-octane gasoline and returns to using regular gasoline, if the calculation is performed in an operating range where there is a shift toward the retard side of the instantaneous lower limit value tAKC3,%,7 of the retard amount, the learning Since the instantaneous lower limit value tAKC3,n of the retard angle is retarded throughout each operating range by the action of the value AGKC3, excessive knock does not occur.

〔Effect of the invention〕

As explained above, according to the ignition timing control device for an internal combustion engine of the present invention, the effective ignition timing at the moment when the operating state shifts to any operating region where knock occurs is set to the retard angle that was last calculated in the previous learning region. Since the angle can always be set to the side advanced by a certain amount from the amount AKC5, there is an effect that excessive knocking and excessive retardation do not occur.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an ignition timing control device for an internal combustion engine according to the present invention, FIG. 2 is a schematic configuration diagram of an engine equipped with the ignition timing control device for an internal combustion engine according to the present invention, and FIGS.
The figure is a flowchart showing the operation of the control circuit of Fig. 2, and Fig. 6 is a flowchart showing the operation of the control circuit of the present invention.
The torque characteristic diagram, FIG. 7, is a three-dimensional map for explaining the operation of the device of the present invention. 10... Engine cylinder block, 12... Knock sensor, 14... Distributor, 16.17.
...Crank sensors, 20...Control circuit, 22...
・Intake passage, 24...Air flow meter, 28...
・Spark plug, 30...Fuel injection valve.

Claims (1)

[Scope of Claims] Basic ignition timing calculation means that calculates the basic ignition timing according to the operating state of the engine; and a retardation amount lower limit value that calculates a predetermined lower limit value of the retardation amount according to the operating state of the engine. a calculation means, a retard correction amount calculation means for calculating a retard correction amount from the basic ignition timing depending on the presence or absence of knocking, and a learned value updating means for updating a learned value for correcting the retard amount lower limit value; Retard angle instantaneous lower limit value calculating means for calculating the retard angle instantaneous lower limit value from the retard angle lower limit value and the learned value; and a retard angle controller that limits the retard angle correction amount by the retard angle instantaneous lower limit value. An ignition timing control device for an internal combustion engine, comprising: correction amount limiting means; and ignition timing correction means for controlling ignition timing by correcting the basic ignition timing using the retardation correction amount.