JPS63113157A - Engine controller - Google Patents

Abstract

PURPOSE:To prevent knocking from occurring so effectively, by compensating ignition timing by learning value at the time of the specified air-fuel ratio, and at the time of an air-fuel ratio out of the specified one, and calculating a correction factor on the basis of this learning value, then compensating the ignition timing. CONSTITUTION:A controller 26, where each signal out of an oxygen sensor 25, a knock sensor 19 or the like is inputted, compensates ignition timing with the ignition timing compensating learning value conformed to the specified air-fuel ratio. At this time, in learning value at the ignition timing, there are provided with two maps, one that corresponds to an air-fuel ratio at a time when the air-fuel ratio is controlled to the richest side and the other that corresponds to the air-fuel ratio controlled to the leanest side. Now, when the air-fuel ratio is controlled between both of them, an ignition timing correction factor corresponding to the air-fuel ratio is calculated from both learning values at the rich side and the lean side. Therefore, such a control unit that is excellent in responsiveness and prevents knocking from occurring is securable without entailing any increase in memory capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine control device, and particularly to an engine control device that controls the air-fuel ratio according to the operating state of the engine, and also controls the ignition according to the occurrence of knocking. The present invention relates to a control device that controls timing.

(Prior art) In an engine air-fuel ratio control device, the air-fuel ratio is controlled to reduce the air-fuel ratio during a predetermined operating state.
A correction value corresponding to the fuel ratio is stored, and when the operating state reaches the corresponding operating state, so-called air-fuel ratio learning control is performed in which the stored value is used without calculating a new air-fuel ratio. An air-fuel ratio control device is known that improves responsiveness and ensures stability of control.

JP-A-57-210137 discloses such an air-fuel ratio learning control device, and according to this disclosed device, the air-fuel ratio is set in feedback control of the air-fuel ratio performed according to the exhaust concentration. The learned value is used in open-loop control of the air-fuel ratio.

By the way, in engines that perform air-fuel ratio control, when the air-fuel ratio changes, the limit at which abnormal combustion such as engine knocking occurs changes. It is desirable to control the ignition timing accordingly.

In view of these circumstances, in addition to carrying out learning control of the air-fuel ratio, the learning value of the ignition timing correction coefficient corresponding to this air-fuel ratio is set and memorized, and learning control of the ignition timing is performed according to changes in the air-fuel ratio. It is proposed that. By performing learning control of the ignition timing in this manner, responsiveness of the ignition timing control can also be improved in response to changes in the air-fuel ratio.

(Problem to be solved) However, with the method proposed above, when operating at an air-fuel ratio for which a learned value for ignition timing is prepared, it is difficult to perform appropriate ignition timing control with good responsiveness. However, in the case of other air-fuel ratios, the ignition timing must be calculated in such a way as to ensure as high output as possible while taking into consideration the knocking situation in each case, resulting in a problem of decreased responsiveness. There is. Furthermore, there is a problem in that control accuracy deteriorates because there are variations in the relationship between the occurrence of knocking and individual ignition timings.

In order to solve this problem, one possible method is to store a learned value for correcting the ignition timing for each air-fuel ratio.
In this method, the map of learning values becomes enormous, resulting in an increase in memory capacity.

(Means for Solving the Problems) The present invention has been constructed in view of the above circumstances, and it is possible to solve the problem without increasing the memory capacity of the electronic control unit.
It is possible to perform appropriate ignition timing control with good responsiveness,
It is therefore an object of the present invention to provide an engine control device that can effectively prevent the occurrence of knocking.

That is, the control device of the present invention includes an air-fuel ratio control means that controls the air-fuel ratio according to the operating state of the engine, a knock sensor that detects engine knocking and outputs a signal according to the magnitude of the knocking, and and ignition timing control means for advancing the ignition timing at the time of occurrence of knocking according to the output of the sensor, the ignition timing control means advancing the ignition timing according to the output of the knock sensor. ignition timing correction means for setting an advance amount as a learned value corresponding to a predetermined air-fuel ratio and correcting the ignition timing based on the learned value when the air-fuel ratio is the predetermined air-fuel ratio; The correction means is configured to use the learned value to calculate an ignition timing correction coefficient at the air-fuel ratio when the air-fuel ratio is other than the predetermined air-fuel ratio, and correct the ignition timing based on the value of the correction coefficient. It is characterized by having been.

According to the present invention, preferably, the air-fuel ratio is feedback-controlled so that the air-fuel ratio becomes a desired value according to the oxygen concentration in the exhaust gas, and under predetermined operating conditions,
The air-fuel ratio learning control is performed by setting a learning value of the air-fuel ratio and controlling the air-fuel ratio according to this learning value. Further, according to the present invention, an ignition timing correction learning value for correcting the ignition timing is prepared corresponding to a predetermined air-fuel ratio, and when the air-fuel ratio reaches the predetermined air-fuel ratio,
Ignition timing is corrected using this learned value. In this case, the learned value of the ignition timing preferably corresponds to the air-fuel ratio when the air-fuel ratio is controlled to the richest side and the air-fuel ratio when the air-fuel ratio is controlled to the leanest side in the relevant operating region. Two values are prepared as a map. When the air-fuel ratio is controlled between the two, the ignition timing correction coefficient corresponding to the air-fuel ratio is determined using the rich-side learned value and the rich-side learned value.

(Effects of the Invention) According to the present invention, the air-fuel ratio is controlled according to the output of the knock sensor, and the ignition timing is also controlled by learning in response to changes in the air-fuel ratio. This makes it possible to control the engine with good responsiveness and high precision. In particular, when the air-fuel ratio is a value other than the value corresponding to the learned value for ignition timing correction, the learned value is used to calculate the ignition timing correction coefficient corresponding to the air-fuel ratio, so the ignition timing correction It is sufficient to prepare two maps of learning values for use, which simplifies the configuration. That is, according to the present invention, in order to increase the memory capacity,
Ignition timing control with good responsiveness can be performed regardless of changes in the air-fuel ratio.

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

Device Configuration Referring to FIG. 1, there is shown a schematic configuration diagram of an engine 1 to which the present invention can be applied.

The engine 1 of this example includes a cylinder block 2 and a cylinder head 3 assembled from above the cylinder block 2.
A cylinder bore 5 is formed inside the cylinder block 2 in which a piston 4 slides back and forth. The piston 4 is connected to a crankshaft (not shown) via a connecting rod 6. The space above the piston 4 of the cylinder bore 5 and the space below the cylinder rad 3 are as follows:
A combustion chamber 7 is configured. An intake boat 8 and an exhaust port 9 are opened in the combustion chamber 7, respectively, and an intake valve 10 and an exhaust valve 11 are combined with the boats 8 and 9. The intake boat 8 and the exhaust port 9 are provided with an intake passage 1.
2 and the exhaust passage 13 communicate with each other. Further, a water jacket 14 is formed around the cylinder bore 5 of the cylinder block 2 .

An air flow meter 15 for measuring the intake flow rate is located upstream of the intake passage 12, and a throttle valve 1 is located downstream of the air flow meter 15.
6 is provided. The throttle valve 16 includes the valve 16
A throttle valve opening sensor 17 is attached to detect the opening of the throttle valve.

Furthermore, near the combustion chamber 7 on the downstream side of the intake passage 12,
A fuel injection valve 18 is attached.

Furthermore, a knock sensor 19 is attached to the cylinder block 2 to detect the occurrence of knocking by detecting engine vibration. Further, an ignition plug 20 faces the combustion chamber 7, and the engine 1 includes an ignition coil 21 that generates an ignition voltage, and a distributor 2 that outputs an ignition signal to the ignition plug 20.
2. A crank angle signal is also detected from this distributor 22. moreover,
The intake passage 12 is provided with an intake air temperature sensor 23 for detecting intake air temperature, and the cylinder block 2 is provided with a water temperature sensor 24 for detecting engine cooling water temperature. Further, the exhaust passage 13 is provided with an 02 sensor 25 that detects the oxygen concentration in the exhaust gas.

The engine of this example includes a controller 26 preferably composed of a microcomputer in order to control the fuel injection amount and engine ignition timing. The controller 26 includes a signal representing the throttle valve opening from the throttle valve opening sensor 17, a signal representing the occurrence and magnitude of knocking from the knock sensor 19, a signal representing the amount of intake air from the air flow make 15, and a signal representing the intake air amount from the air flow make 15. A crank angle signal, that is, an engine rotation speed signal, from the 02 sensor 22, and a signal indicating the oxygen concentration in the exhaust gas from the 02 sensor 25 are input. The controller 26 also receives a signal from an intake air temperature sensor 23 that indicates the intake air temperature, and a water temperature sensor 2 that indicates the engine coolant temperature.
The signal from 4 is human-powered.

The controller 26 calculates the air-fuel ratio in the operating state based on these signals, and outputs a signal representing the injection pulse width of the fuel injection valve to the fuel injection valve I8 so that the air-fuel ratio becomes a desired value. At the same time, the ignition timing is corrected using the learned value according to the air-fuel ratio and the occurrence of knocking at that time, and a desired ignition signal is output to the ignition plug 20.

Control details Below, regarding the air-fuel ratio control and ignition timing control of this example, the second
This will be explained with reference to FIGS. 7 to 7.

Air-fuel ratio control FIGS. 2 to 4 show flowcharts of the basic routine of control performed by the controller 26.

First, referring to FIG. 2, the controller 26 system is initialized (step Sl). Next controller 2
6 is based on the signal from the distributor 22, the engine rotation speed Ne, and the signal from the air flow make 15.
The intake air amount Qa is calculated (step S2.33).

Next, the controller 26 calculates the intake air filling amount Ce from the engine speed Ne and the intake air amount Qa (step S4). Then, the filling ice, and the engine speed Ne
Determine the basic ignition timing An from the map prepared with the parameters as parameters, and then determine the basic fuel injection amount T from the
, is calculated (steps S5, S6).

Next, the controller 26 determines whether or not the air-fuel ratio and ignition timing are controlled in a knock control region based on the value of the filling fi Ce, depending on the occurrence of knocking (step S7). In other words, the filling amount Ce is the predetermined value Cek
If it is larger than , the controller 26 determines that it is in the knock control region, and sets the knock control flag Fkc to 1 (step S8).

If not, the knock control flag Fkc is set to 0 (step S9).

Next, the controller 26 determines whether the operating state is in the enriched region from the values of the filling amount Ce and the engine speed Ne. That is, when the charging tiCe is greater than or equal to the predetermined value CeL and the engine speed Ne is the predetermined value NeL, it is determined that the enrichment region is reached, and the enrich flag FEN and lean flag FL) are set to O. , the air-fuel ratio correction coefficient 0A7F is 1.2
(Steps S10, S11.512, S13
and 514).

When the operating region is not an enriched region, the controller 26 calculates the increase dCe in charge:tJ i Ce and sets the enrich flag FEIL to O.
It is determined whether or not the vehicle is in an accelerated state based on the increase dCeO value of the filling amount Ce (step S15.516). That is, when the increase dCe is larger than the predetermined value dcAcc, it is determined that the vehicle is in an accelerated state (step 517). If the operating state is not in an acceleration state, an air-fuel ratio learning completion flag F A/
The value of F is determined (step 518). When the value of the learning completion flag F A/F is 1, the controller 26 determines that learning of air-fuel ratio control is complete and performs lean control. That is, the air-fuel ratio correction coefficients CA and F are gradually decreased (step 519). In this case, the controller 26 sets the lower limit value of the air-fuel ratio correction coefficient CA,F to 0.
．． Therefore, the air-fuel ratio correction coefficient CA
7F will never be less than 0.6. (Steps 320.521). In this case, the controller 26 sets the lean flag FL, which indicates that the operating region is in the lean region, to 1 (step 522).

On the other hand, if it is determined in step S17 that the state is in an acceleration state, or if the learning completion flag FA/F is O in step S18, that is, if the setting stage of the air-fuel ratio learning value is not completed, controller 26
sets the lean flag FLN to 0 (step 52
3) as well as the value of the air-fuel ratio correction coefficient CA, .

In this case, if the current value of the air-fuel ratio correction coefficient CA, F exceeds 1, the value of the coefficient CA, F is set to 1,
If it is less than 1, gradually increase it (step 3
24, S24, S25, S26 and 527).

If the values of coefficients CA and F are set to 1, then
The controller 26 determines the learned value of the air-fuel ratio based on the signal from the 02 sensor 25. In this case, the controller 26 outputs the output ■ from the O2 sensor 25. The value of 2 is read (step 528).

And the output ■. The value of 2 corresponds to the stoichiometric air-fuel ratio (
In the case of the 02 sensor 25 of this example, it is determined whether the voltage is larger than 0.5 V (step 529).

Output ■. If 2 is greater than 0.5■, the previous output■. A determination is made as to whether 2' is greater than 0.5■ (step 530). Previous output■. 2 is 0.5
If it is not larger than V, it becomes clear that the air-fuel ratio has changed from the lean side to the rich side for the first time, that is, the air-fuel ratio has been reversed between lean and rich. In this case, the controller 26 accumulates the air-fuel ratio feed pack correction coefficients CF and B at the time of this reversal (step 531), and the number of reversals NF/[l reaches a predetermined value (eight times in this example). It is determined whether or not (step 532). Then, the number of reversals NP/B is a predetermined value of 8.
If the value has been reached, the controller 26 updates the air-fuel ratio learning correction value CLC according to a predetermined arithmetic expression (step 533), adds the learning number counter NLC, and sets the learning control register RRSRL% and the number of reversals. The counter N F/B of is cleared (step S34.335). Note that when the learning number counter NLC reaches a predetermined value (16 in this example), the controller 26 determines that the step of setting the learned value of the air-fuel ratio has ended.
Set learning completion flag FA/F to 1 (step 33
6.537). Next, the controller 26 outputs the O2 sensor 25 (■). , updates the value (step 538).

Then, the air-fuel ratio correction coefficient CA/P is gradually decreased (
step 539).

On the other hand, the controller 26, in step S29,
02 Output of sensor 25 ■. If 2 is not greater than 0.5■, the previous output■. A determination is made whether 2' is greater than 0.5V (step 540). If the previous output VO2' was larger than 0.5 V, it becomes clear that the air-fuel ratio has reversed from the lean side to the rich side this time. Therefore, in this case, the controller 26 accumulates the air-fuel ratio feedback correction coefficients C, . . . on the lean side (step 541). Then, a counter NF/l for the number of reversals is added (step 542
), and the output VO2 value of the 02 sensor 25 is updated (step 543). Then, the air-fuel ratio correction coefficient CA,
, gradually increases (step 544).

Note that in step S40, the previous 02 sensor 25
output V. If 2' is not greater than 0,5■, then
In other words, if the air-fuel ratio continues to be on the lean side,
The controller 26 performs steps 341, S42, and S
Step 344 is executed without performing the process of 43 to obtain the air-fuel ratio correction coefficient CA.

gradually increase.

Note that in step 526, the air-fuel ratio correction coefficient CA/F
is larger than 1, the register R11s RL % related to learning control and the counter N F/B of the number of reversals are cleared in preparation for learning control (step 545
).

Next, the controller 26 reads the battery voltage ■8 as shown in FIG. 4 (step 546), and disables the fuel injection valve 18 in light of the characteristics shown in FIG. Injection time Tv
is calculated (step 547).

The controller 26 then calculates the final fuel injection time T1 using the various correction coefficients obtained in the above procedure (step 548).

ignition timing control Next, ignition timing control will be explained.

The controller 26 determines the values of the knock control flag Fkc and the enrichment flag FER, and determines whether or not to perform ignition timing learning (step S49.550).
. In this case, the controller 26 is provided with a map that stores the values of the ignition timing learning value ALe2 created with respect to the filling amount Ce and the engine rotational speed Ne as shown in FIG. This learning value ALCZ serves as a reference for determining the ignition timing learning correction coefficient ALC.

Then, the controller 26 identifies a zone Z for determining the corresponding ignition timing learning correction coefficient ALC from the values of the flags indicating the various operating states.

Note that in step S49, the knock control flag Fk
When c is 00, that is, when it is not in the knock control zone, the value of the ignition timing learning correction coefficient ALC is cleared since ignition timing learning control is not performed in this example (step 551). When the knock control flag Fkc is 1, the enrich flag F! ! When the value of R is 1, that is, in the enriched region, the filling amount Ce is 1 in the corresponding region in FIG.
The zone Z is specified in reference to the value of the engine speed Ne and the engine speed Ne (step 552). In this case, in Figure 6,
The enriched region is indicated by zone Zn. Next, the controller 26 employs the learning value ALCZ stored in the zone Z specified in the above procedure as it is as the ignition timing learning correction coefficient ΔLC (step S5
3〉. Then, in order to permit updating of this ignition timing learning value, a learning permission flag FLC is set to 1 (step 554).

Further, when the values of the enrich flags FE and I are 0, the value of the lean flag FLN indicating that the operating region is in the lean region is determined (step 555). Furthermore, if the air-fuel ratio correction coefficient CA/P is 0. 6 or 1 (step S56.557). If the air-fuel ratio correction coefficient C1/F is 0.6 or 1, the controller 26 executes step S52 to identify zone Z. In this case, in FIG. 6, in the lean region, two learning values are prepared for zone Z given by the same filling amount Ce and engine speed Ne, and the air-fuel ratio correction coefficient CA is set to 0.6. For example, the learned value A stored in zone Zn is 1, whereas the learned value A LCZ stored in zone Zn is 1. 2 is selected as the ignition timing learning correction coefficient ALC (step 553). Note that the controller 26 also executes step S54 in this case and sets the learning permission flag F't.
Set c to 1.

On the other hand, in steps 356 and S57, if the air-fuel ratio correction coefficient CA/F is neither 0.6 nor 1, the controller 26 sets the learning permission flag FLe to 0, and performs the ignition timing learning value update process. is prohibited (step 858), and the filling amount Ce and engine speed N
In light of the value of e, the learned value AZL stored in the zone ZnL corresponding to the coefficient CA/F of 0.6 and the coefficient CA
The ignition timing learning correction coefficient ALC is calculated using the learning value AZR stored in the zone Zn, where /F corresponds to 1 (step 559).

After executing the above processing, the controller 26 returns to step S2 again.

Next, with reference to FIG. 7, ignition timing learning value update control, final ignition timing calculation procedure, and output control will be described.

FIG. 7 shows a flowchart of an included routine that is executed by interrupting the basic control routine explained with reference to FIGS. 2 to 4 at a predetermined timing.

In this routine, the controller 26 determines the value of the knock control flag Fkc (step 560), and if this value is 1, that is, in the knock control' region, the controller 26 determines the knocking intensity based on the signal from the knock sensor 19. ■Read the file (step 561). When the knocking intensity 1g is greater than 0, that is, when knocking is occurring, the feedback correction coefficient A P/B for correcting the ignition timing to the retard side is adjusted according to the magnitude of the knocking intensity I. Increase (Step 3
62.563). Next, the controller 26 sets a learning permission flag F. (step 564), and if this value is 1, it is further determined whether the knocking intensity IK is greater than a predetermined value IWLC (step 565), and if it is greater, the operating state Learning value Δ,. 2 as the above feedback correction coefficient ΔF/It
is corrected to the retard side using (step 566). and a counter N indicating that knocking has not occurred. is cleared (step 567). Next, the controller 26 calculates the final ignition timing As from the values of the basic ignition timing AI1% ignition timing learning correction coefficient ALC and the feedback correction coefficient AP/B according to a predetermined calculation formula (step 568). Based on this ignition timing, an ignition signal is output to the spark plug 20 at a predetermined timing (step 569), and at a predetermined timing, the final fuel injection time TI obtained in the basic routine is
Based on this, an injection signal is output to the fuel injection valve 18 (step 570).

Note that if it is determined in step S60 that it is not in the knock control region, the controller 26 clears the feedback correction coefficient A F/B (step 57).
1), proceed to step 368. Further, in step S62, if it is determined that knocking has not occurred, the controller 26 controls the feedback correction coefficient A17.
B is decreased by a predetermined amount dA and corrected to the advanced angle side (step 572). If knocking has not occurred, the controller 26 next determines the value of the learning permission flag FLC (step 573), and if the learning permission condition is satisfied, the feedback correction coefficient AP/B is not 01. After confirming (step 574) counter N
Add xx (step 575).

If the value of the counter NK,l is greater than or equal to the predetermined value NK,lLc (step 576), the ignition timing learning value ALCZ is decreased by a predetermined amount dAtc to correct the advance angle correctly in step S7? ), proceed to step 368.

According to the control of this example as described above, by combining the air-fuel ratio control and the ignition timing learning control, it is possible to control the engine with high responsiveness and high precision. Moreover, in the ignition timing control of this example, only two maps are required for learning control, and therefore,
Increase in memory capacity can be suppressed as much as possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an engine to which the control according to the present invention can be applied, and FIGS. 2, 3, and 4 are
A flowchart of the basic routine of control in the control device of this example, FIG. 5 is a graph showing the relationship between changes in battery voltage and invalid injection time, and FIG. 6 can be used as a map of learned values of ignition timing. FIG. 7, which is a graph showing the relationship between the filling amount and the engine speed, is a flowchart of an included routine that forms part of the control content of this example. 1... Engine, 2... Cylinder block, 3... Cylinder head, 4...
... Piston, 5 ... Cylinder bore, 6 ... Connecting rod, 7 ...
...Combustion chamber, 8...Intake boat, 9...
...Exhaust port, 10...Intake valve, 1
1...exhaust valve, 12...intake passage,
13...Exhaust passage, 14...Water jacket, 15...Air flow meter, 16...Throttle valve, 17...Throttle valve open Degree sensor, 18...
... Fuel injection valve, 19 ... Knock sensor, 2
0...Spark plug, 21...Ignition coil, 22...
...Distributor, 23...Intake air temperature sensor, 24...Water temperature sensor, 25...
02 Sensor 25.26... Controller.

Claims (1)

[Claims] An air-fuel ratio control means that controls the air-fuel ratio according to the operating state of the engine, a knock sensor that detects engine knocking and outputs a signal according to the magnitude of the knocking, and a time point at which knocking occurs according to the output of the knock sensor. 2. An engine control device comprising: ignition timing control means for advancing the spark timing, the ignition timing control means adjusting the advance amount determined according to the knock sensor output to a predetermined air-fuel ratio. and ignition timing correction means for correcting the ignition timing based on the learned value when the air-fuel ratio is the predetermined air-fuel ratio. When the air-fuel ratio is other than the air-fuel ratio, an ignition timing correction coefficient for the air-fuel ratio is calculated using the learned value, and the ignition timing is corrected based on the value of the correction coefficient. Device.