JPH0381566A - Ignition time controller of internal combustion engine - Google Patents

Abstract

PURPOSE:To realize an operation of good acceleration by a method wherein ignition time is set to first ignition time retarded with respect to optimum ignition time for a specific time after fuel cut and after a specified time has passed, ignition time is set to second ignition time further retarded with respect to the first ignition time. CONSTITUTION:When acceleration is started with recovery from deceleration operation with fuel feed stopped detected by a recovery detecting means A, an elapse time detecting means B detects the elapse time after recovery. Then, until this elapse time reaches predetermined set time, ignition time is set to first ignition time retarded with respect to optimum ignition time by a first ignition time setting means 1. Therefore engine output rises slowly thereby preventing acceleration shock. When the above predetermined time is reached, a second ignition time setting means D sets the ignition time to second ignition time further retarded with respect to the first ignition time. When the above elapse time exceeds the above set time, a third ignition time setting means E gradually advances ignition time toward optimum ignition time.

Description

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

(1) [Prior art] In a case where the fuel supply is cut during deceleration operation in order to reduce fuel consumption, if acceleration operation is started during deceleration operation and the fuel supply is started, the engine stops. Acceleration shock occurs due to the sudden generation of large output torque. Therefore, in order to prevent the occurrence of such acceleration shock, the ignition timing is temporarily retarded by a large amount when fuel supply is started, that is, when returning from the fuel cut state, and then the ignition timing is gradually advanced. An internal combustion engine with an angular structure is known (see Japanese Patent Application Laid-open No. 145819/1983).
.

In this way, if the ignition timing is delayed when returning from a fuel cut state, the engine output will not rise suddenly, thereby preventing acceleration shock from occurring, but the engine output will not increase in response to the accelerator pedal depression. A problem arises in that a good sense of acceleration cannot be obtained because the vehicle does not rise quickly with good responsiveness.

Therefore, in order to solve this problem, (2) When returning from a fuel power cut state, the ignition timing is set to the optimal ignition timing for a certain period of time after recovery, and after a certain period of time, the ignition timing is temporarily delayed by a wide range. An internal combustion engine is known in which the ignition timing is gradually advanced to the optimum ignition timing (Japanese Patent Laid-Open Nos. 56-50265 and 113-1982).
050 and Japanese Unexamined Patent Publication No. 63-201372>. In these internal combustion engines, the ignition timing is set to the optimum ignition timing for a certain period of time after returning from the fuel cut state, so the engine output immediately increases when the accelerator pedal is depressed.

[Problem to be solved by the invention]

However, if the ignition timing is set to the optimum ignition timing for a certain period of time after returning from the fuel cut state, the engine output will rise rapidly, which will first of all cause the problem of acceleration shock. Secondly, if the ignition timing is significantly retarded after a certain period of time has elapsed after returning from the fuel cut state, the engine output will be sharply reduced, causing a temporary drop in acceleration. It turns out. That is, there is a problem that a good acceleration feeling cannot be obtained because a feeling of deceleration occurs in the acceleration (3) driver.

[Means to solve the problem]

In order to solve the above problems, according to the present invention, as shown in the configuration diagram of the invention in FIG. time detection means B, and first ignition timing setting means C for setting the ignition timing to a first ignition timing retarded with respect to the optimum ignition timing until the elapsed time described above reaches a predetermined set time. a second ignition timing setting means for setting the ignition timing to a second ignition timing that is further retarded than the first ignition timing when the elapsed time reaches the set time; The third ignition timing setting means E is provided for gradually advancing the ignition timing from the second ignition timing to the optimum ignition timing after the above-mentioned set time has been exceeded.

(4) [Function] After returning from the fuel cut state, the ignition timing is set to the first ignition timing retarded with respect to the optimum ignition timing for a certain period of time, so the engine output rises slowly. Acceleration shock does not occur. In addition, when the ignition timing is retarded from the first ignition timing to the second ignition timing after a certain period of time has elapsed, the first ignition timing is retarded.
Since the ignition timing of the engine is retarded, the amount of retardation from the first ignition timing to the second ignition timing is small, so there is no drop in engine output, so the acceleration continues to increase.

〔Example〕

Referring to Figure 2, 1 is the engine body, 2 is the piston, and 3
4 is the cylinder head, 4 is the combustion chamber, 5 is the ignition plug, 6 is the intake valve, 7 is the intake boat, 8 is the exhaust valve, and 9 is the exhaust port, and the intake boat 7 is connected to the surge through the corresponding branch pipe 10. It is connected to the tank 11.

A fuel injection valve 12 is attached to each branch pipe 10, and fuel is injected from these fuel injection valves 12 into the corresponding intake boat 7. The surge tank 11 is connected to an air cleaner (not shown) via an intake duct 13 and an air flow meter 14, and a throttle valve 15 is disposed within the intake duct 13. On the other hand, the exhaust port 9 is connected to an exhaust manifold 16, and an oxygen concentration detector 17 is disposed within the exhaust manifold 16.

The fuel injection valve 12 and the spark plug 5 are controlled by an electronic control unit 30
The injection timing from the fuel injection valve 12 and the ignition timing from the spark plug 5 are controlled based on the output signal of the electronic control unit 30.

The electronic control unit 30 consists of a digital computer with ROMs connected to each other by a bidirectional bus 31.
(Read-on memory) 32, RAM (Random access memory) 33, CPU (Microprocessor) 34
, an input port 35 and an output port 36. The air flow meter 14 generates an output voltage proportional to the amount of intake air, and this output voltage is input to the input port 35 via the AD converter 37. The oxygen concentration detector 17 generates an output voltage of about 0.1 volt when the air-fuel mixture supplied into the engine cylinder is lean, and 0 when the air-fuel mixture supplied into the engine cylinder is rich (6). Generates an output voltage of about .9 volts. The output voltage of this oxygen concentration detector 17 is determined by the AD converter 38.
The data is input to the human power port 35 via. Further, a throttle sensor 18 is attached to the throttle valve 15 to detect that the throttle valve 15 is at an idling opening.
The output signal of this throttle sensor 18 is transmitted to the input port 35.
is man-powered. Further, a water temperature sensor 19 is attached to the engine body l to generate an output voltage proportional to the engine cooling water temperature, and the output voltage of this water temperature sensor 19 is inputted to the human power port 35 via an AD converter 39. Top dead center detection sensor 2
0 generates an output pulse every 180 crank angles, and the crank angle sensor 21 generates an output pulse every 30 crank angles, and these output pulses from the top dead center detection sensor 20 and the crank angle sensor 21 are input to the input port 35. be done.

In the electronic control unit 30, the current crank angle is calculated from the output pulses of the top dead center detection sensor 20 and the crank angle sensor 21, and the engine rotation speed is calculated from the output pulses of the crank angle sensor 21.

On the other hand, the output port 36 has the corresponding drive circuits 40 and 41 (
7) Connected to the spark plug 5 and the fuel injection valve 12 via.

Next, with reference to FIG. 3, the ignition timing control according to the present invention will be explained in comparison with the conventional ignition timing control described above.

In FIG. 3, T indicates when the throttle valve is opened during deceleration operation and acceleration operation is started, and in FIG. The ignition timing control is shown in each figure. In the case of the conventional ignition timing control shown by the broken line, the ignition timing is retarded by a large amount when returning from the fuel cut state, and then the ignition timing is gradually advanced to the optimum ignition timing.

In this case, the acceleration G does not increase for a while after the start of acceleration, and therefore a good acceleration feeling cannot be obtained.

On the other hand, in the case of the conventional ignition timing control shown by the chain line, the ignition timing is set to the optimum ignition timing for a while after returning from the fuel cut state, and then the ignition timing is significantly retarded.

In this case, since the acceleration G rapidly increases at the same time as acceleration starts, (8) acceleration shock occurs at the start of acceleration. Furthermore, when the ignition timing is retarded by a large amount, the acceleration G temporarily decreases, resulting in a feeling of deceleration during acceleration operation, and thus a good sense of acceleration cannot be obtained.

On the other hand, in the case of the ignition timing control according to the present invention shown by the solid lines It and I2, the ignition timing is retarded with respect to the optimum ignition timing for a certain period of time after the start of acceleration, and then, after a certain period of time, the ignition timing is further retarded. be cornered. In this way, by retarding the ignition timing with respect to the optimum ignition timing for a certain period of time after the start of acceleration, the acceleration G increases relatively slowly, so that no acceleration shock occurs. Further, when a certain period of time has elapsed, the ignition timing is further retarded, but since the amount of retardation at this time is small, the acceleration G continues to rise. Therefore, a feeling of deceleration does not occur during accelerated driving, so that good accelerated driving is ensured.

The solid line 1 indicates the first embodiment of the present invention, and in this first embodiment, the optimal ignition timing at the start of acceleration is maintained for a certain period of time after the start of acceleration. A solid line I2 shows a second embodiment according to the present invention. (9) In this second embodiment, the ignition timing is gradually retarded from the optimal ignition timing at the start of acceleration for a certain period of time after the start of acceleration.

Next, an outline of ignition timing control according to the present invention will be explained with reference to FIG.

When the throttle valve 15 is opened during deceleration operation, the fuel cut flag FFC is reset and fuel injection is started. When the fuel cut flag FFC is reset, the counter operation flag FCDLY is set, and when the counter operation flag FCDLY is set, the counter CDL is set.
The count up action of Y is started. A retard control flag FDIIOLD is set from when the counter operation flag FCDLY is set until the count value of the counter CDLY reaches a constant value C8.
While DHDLD is set, the ignition timing is controlled to 11 or I2.

Next, when the count value of the counter CDLY reaches a constant value C8, the retard control flag FDI (OLD is reset,
Maximum retard flag FDMAX and ignition timing return flag FD
ESA is set. When the maximum retard flag FDM is set to X (10), the ignition timing is retarded by a wide range, for example, 5 pm after top dead center.
It is considered a degree. Then, immediately set the maximum retard flag FDMAX.
is reset. Next, the ignition timing reset flag FDBS
While the ignition timing is set, the ignition timing is gradually advanced to the optimum ignition timing, and when the ignition timing reaches the optimum ignition timing, the ignition timing return flag is reset to complete the ignition timing return operation. Counter operation flag F
CDLY is reset and counter CDLY is cleared.

5 to 8 show flowcharts for executing the ignition timing control shown in FIG. 4, and then, while referring to FIG. I will explain about it.

5 and 6 show the control of the fuel cut flag FFC, etc., and first, the control of the fuel cut flag FFC will be explained with reference to FIG.

The process shown in FIG. 5 is executed by interrupts at regular intervals, and first, in step 50, it is determined whether or not the fuel cut flag FFC is set.

(11) When the fuel cut flag FFC has been reset, the process proceeds to step 51, where it is determined whether the engine rotation speed N is higher than a predetermined cut rotation speed N. N>N
+, proceed to step 52 and open the throttle valve 15.
It is determined whether or not the opening degree is the idling opening degree. When the opening is idling, the process advances to step 53 and the fuel cut flag FFC is set. That is, if N>N+ when deceleration operation is started, the fuel cut flag FFC is set and the fuel injection action from the fuel injection valve 12 is stopped.

When the fuel cut flag FFC is set, step 50
Proceeding to step 54, the engine rotation speed N becomes the return rotation speed N.
2 (N2 <N,) is determined. When N<N2, the process proceeds to step 55, where the fuel cut flag FFC is reset and fuel injection is started.

However, at this time, the ignition timing retard control as shown in FIG. 4 is not performed.

't! Figure J6 shows the throttle valve 15 opening from the idling opening based on the output signal of the throttle sensor 18 (1
2) Executed by interrupt when specified.

Referring to FIG. 6, first, in step 60, it is determined whether the fuel cut flag FFC is set. When the fuel cut flag FFC is set, that is, when the fuel supply is stopped, the process proceeds to step 61, where the fuel cut flag FFC is reset,
Fuel injection begins. Next, in step 62, the counter operation flag FCDLY is set, and the process proceeds to step 63. Optimum ignition timing θ according to the current engine operating condition,
are successively calculated in a routine shown in FIG. 8, which will be described later, and in step 63, the optimum ignition timing θ is determined as θ. .

The data is stored in the RAM 33. Therefore, this θHOL
I+ indicates the optimum ignition timing θ when acceleration operation is started during deceleration operation.

FIG. 7 shows the control routine for each flag other than the fuel cut flag FFC and the control routine for the counter CDLY.
This routine is executed by interrupts at regular intervals.

Referring to FIG. 7, first step 70 (13
> Then, it is determined whether the throttle valve 15 is at the idling opening. Step 7 when the opening is idling
1, the counter operation flag FCDLY is reset, and then the process proceeds to step 72, where the ignition timing return flag FCDLY is reset.
DBS is reset, and then the process proceeds to step 73 where the maximum retard flag FDMAX is reset. On the other hand, when the throttle valve 15 is not at the idling opening, the process proceeds to step 74, where it is determined whether or not the counter operation flag FCDLY is set.
If CDLY has been reset, the process advances to step 72.

On the other hand, when the counter operation flag FCDLY is set, that is, when acceleration operation is started from a deceleration operation state where fuel supply is stopped and fuel injection is started, the process advances to step 75 and the counter CDLY is counted up. is started. Next, in step 76, it is determined whether the count value of the counter CDLY is larger than C8 (FIG. 4), for example, whether one second has elapsed since the start of counting. If - seconds have not elapsed, the process proceeds to step 77 (14), where it is determined whether exactly 1 second has elapsed since the start of counting. If it is not exactly 1 second, that is, if 1 second has not elapsed since the start of counting, the process advances to step 78 where the maximum retard flag FDMAX is reset, and then the process advances to step 79 where the retard control flag FDHO is reset.
LD is set. Therefore, the count operation flag FCD
Immediately after LY is set, the retard control flag FDHD
LD will be set.

On the other hand, when one second has elapsed since the start of counting, the process proceeds to step 80, where the maximum retard flag PDMAX is set, and then, at step 81, the ignition timing return flag PDBSA is set. Next, in step 82, the count value of the counter CDLY is set to C8 (FIG. 4), ie, 1 second, and then the process proceeds to step 83, where the retard control flag FDHDLD is reset.

In the next processing cycle, in step 75, the counter C
Since DLY is counted up, it is determined in step 76 that CDLY>1 second, and the process then proceeds to step 84. In step 84, the maximum retard flag (15) FDMAX is reset, and the process proceeds to step 82.

FIG. 8 shows a first embodiment of the ignition timing control routine, and this routine is executed by interruption at every fixed crank angle.

Referring to FIG. 8, first, in step 90, it is determined whether the retard control flag FDIIOLD is set. When the retard control flag FDH[]LD is set, the process proceeds to step 91 and θ□. L[1
is set as the ignition timing θe, and then in step 92 ignition is performed by the ignition plug 5 at the ignition timing θe. Therefore, as shown in FIG.
While D is set, the ignition timing is maintained at θHOL[l, as shown by ■.

On the other hand, in step 90, the retard control flag FDIl[
] If it is determined that the LD has been reset, the routine proceeds to step 93, where the basic ignition timing θBASE is calculated from, for example, the intake air amount and the engine speed. Then step 9
4 is a correction value θ based on engine cooling water temperature, etc. is calculated, and then in step 95 θBAS□ and θ.

The optimum ignition timing θ is calculated from Then Ste (16
) At knob 96, it is determined whether or not the ignition timing return flag FDBSA is set, and at step 97, it is determined whether or not the maximum retard flag FDMAX is set. When the retard control flag FDHDLD is reset, the ignition timing return flag FDIESA is reset as shown in FIG.
Since the maximum retard flag FDMAX is set, the process proceeds to step 98 and the ignition timing θe is set to a predetermined maximum retard, for example, 5 degrees after top dead center. That is, when the retard control flag FDHDLD is reset, the ignition timing is retarded from θ)IOLD to 5 degrees after top dead center, as shown in FIG.

Since the maximum retard flag FDMAX is reset immediately after being set, step 97 is executed in the next processing cycle.
The process then proceeds to step 99, where the ignition timing θe is advanced by one degree. Next, in step 100, it is determined whether the ignition timing θe is greater than the optimum ignition timing θ. If θe≧θA, the process proceeds to step 101, where the ignition timing θ is set as the optimum ignition timing θ. Next, in step 102, the counters CDt, Y are cleared and the ignition timing return flag FD is cleared.
ESA is reset and (17> counter operation flag FCDLY is reset. Therefore, as shown in FIG. 4, the ignition timing return flag FDBS
While A is set, the ignition timing θe is gradually advanced by 1 degree from 5 degrees after top dead center, and when the ignition timing θG reaches the optimum ignition timing θ, the ignition timing θe reaches the optimum ignition timing θ. will be maintained.

FIG. 9 shows a second embodiment of the ignition timing control routine. The only difference between this embodiment and the first embodiment shown in FIG. 8 is the part surrounded by the chain line, and therefore the description will focus on the part surrounded by the chain line.

In this second embodiment, in step 91, the ignition timing θe
is θ□. When the LD is set, the process proceeds to step 110, where a predetermined constant continuous angle Δθ is added to the retard amount Σθ, and then, in step 111, the retard amount Σθ is subtracted from the ignition timing θe. As a result, the ignition timing θe is gradually retarded while the retard control flag FDHDLD is set, as indicated by black in FIG. Next, the retard control flag FDHOLD is reset, and when the ignition timing θe is retarded by 5 degrees after the top dead center, the retard amount Σθ is cleared (18) in step 112.

〔Effect of the invention〕

When accelerating operation is started from decelerating operation when the fuel supply is stopped, the acceleration increases relatively slowly at the start of acceleration, and then the acceleration does not drop (it increases slowly, so good acceleration operation is possible). can be ensured.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of the present invention, Figure 2 is an overall diagram of the internal combustion engine,
Fig. 3 is a time chart for explaining the ignition timing control according to the present invention in comparison with the conventional one, Fig. 4 is a time chart of the ignition timing control according to the present invention, and Figs. flowchart to control,
FIG. 7 is a flowchart for controlling each flag, FIG. 8 is a flowchart for a first embodiment for controlling ignition timing, and FIG. 9 is a flowchart for a second embodiment for controlling ignition timing. . 5... Spark plug, 12... Fuel injection valve, (1
9) 15... Throttle valve.

Claims (1)

[Claims] return detection means for detecting return from the fuel cut state;
an elapsed time detection means for detecting the elapsed time after recovery; and an elapsed time detection means for setting the ignition timing to a first ignition timing retarded with respect to the optimum ignition timing until the elapsed time reaches a predetermined set time. a second ignition timing setting means that sets the ignition timing to a second ignition timing that is further retarded than the first ignition timing when the elapsed time reaches the set time; An ignition timing control device for an internal combustion engine, comprising third ignition timing setting means for gradually advancing the ignition timing from the second ignition timing to the optimum ignition timing after the elapsed time exceeds the set time.