JPS6135379B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition timing control method for performing feedback control of ignition timing in order to improve the output and fuel consumption rate of an internal combustion engine.

The ignition timing of an internal combustion engine is adjusted to the operating condition of the internal combustion engine so that the engine's output can be maximized and at the same time the fuel consumption rate can be minimized, unless there are special reasons such as knocking or problems with exhaust gas characteristics. Together,
The ignition timing is adjusted by the rotational speed and intake pressure.
However, these conventional methods have limitations and some loss in power and fuel consumption. For example, variations in individual engines,
These include variations in ignition timing correction and changes in environmental conditions.

In order to eliminate these losses and maximize internal combustion engine output, methods have been devised to feedback control the ignition timing, for example, as disclosed in U.S. Patent No.
It is known from the specification of No. 3142967. According to this, the engine was operated at two different ignition timings near the target ignition timing, and among these two points, the rotation speed Nr when operating at the delayed ignition timing, and then the engine speed at the advanced ignition timing. By detecting the rotational speed Na and comparing the magnitude of both rotational speeds, when Nr<Na, the target ignition timing is advanced by a predetermined value, and when Nr>Na, it is corrected to be delayed by a predetermined value. As a result, the ignition timing is controlled at the optimum ignition timing to provide the maximum torque of the engine.

However, when determining a change in output based on the number of revolutions, for example, although the number of revolutions changes due to various factors, in this method it is difficult to determine whether the change in the number of revolutions is due to ignition timing or whether it is due to external factors (e.g. Since there is no ability to determine whether the cause is due to accelerator operation), the ignition timing is corrected in the opposite direction to the optimal ignition timing that gives the maximum torque during acceleration or deceleration, or when climbing or descending slopes. decreases,
In some cases, this caused deterioration in output and fuel efficiency.

The present invention has been made in view of the above problems, and
At least 〓〓〓〓 in the vicinity of the target ignition timing and different from each other.
also select two ignition timing points, operate the internal combustion engine alternately for a predetermined period at least at the selected two ignition timing points, and determine the engine speed when operating at each of these ignition timing points. Detecting a signal, a torque signal, or a signal of an operating state related to these, and comparing detection signals of at least three consecutive points among the detection signals obtained when operating at the at least two points of ignition timing. The system is characterized in that it determines whether the target ignition timing is ahead or behind the optimal ignition timing that maximizes the engine output, and corrects the target ignition timing. It is possible to identify whether the detection signals such as rotation speed, torque, etc. have changed due to various factors, or whether the detection signals such as rotation speed, torque, etc. have changed due to changes in the ignition timing at two different points, and the target ignition timing can be determined without error. The purpose is to adjust the ignition timing to the optimum level to maximize engine output while minimizing fuel consumption.

An embodiment of the apparatus to which the method of the present invention is applied will be described below with reference to the block diagram of FIG. 1 is an internal combustion engine, 2 is an ignition device, and 3 is an intake system. 5 is an intake pipe pressure sensor that detects the intake pipe negative pressure of the internal combustion engine, 6 is a rotation angle sensor, and 4 is a computer using a microprocessor. The engine condition is detected from the output of the pressure sensor 5, the optimum ignition timing at that point is calculated, and a signal indicating the actual ignition timing energization start timing is output to the ignition device 2 according to the calculation result. As is well known, the ignition device 2 energizes the primary coil of the ignition coil in response to the energization start timing signal, cuts off the current to the primary coil in response to the ignition timing signal, and transmits the high voltage generated by the secondary coil to the corresponding one. The power is distributed and applied to the spark plugs of the cylinders. 7 is an in-vehicle battery, and 8 is a power supply circuit for the computer. Note that the configuration of the computer 4 is well known, and the content of the arithmetic processing is unique for carrying out the control method of the present invention, so a detailed circuit description will be omitted and the content of the arithmetic processing will be explained using a flowchart.

FIG. 3 is a flowchart schematically showing the arithmetic processing contents of the computer 4, that is, the ignition timing control program, and FIG. 4 is a time chart for explaining its operation, which will be explained below.

When the internal combustion engine 1 starts, the program starts at step 440 and initializes the corrected advance angle θ _B to zero. At this point, a counter that counts the number of ignitions is set to 0. First, in step 400, a basic advance angle θmap is calculated from the outputs of the rotation angle sensor 5 and the intake pipe pressure sensor 6. This basic advance angle θ
The map is mapped and stored in the memory of the computer 4 in correspondence with the rotational speed and intake pipe pressure, and since it is well known, a detailed explanation will be omitted. Next, in step 401, the modified advance angle θ is added to the basic advance angle θmap.
A target advance angle (target ignition timing) is obtained by adding _B , and in step 402, a control signal (ignition signal) corresponding to this ignition timing θ is generated. Step 403
The number of ignitions n is increased by 1 at step 404, and the process branches to NO until the ignition rotation n reaches the set number of ignitions K at step 404, and steps 400 to 404 are looped. In this embodiment, K=3 is set as shown in FIG. 4D. If the number of ignitions n matches the set rotation speed K, then
The process branches to YES, and in step 405, the pulse count value N _B of constant frequency clock pulses for K ignitions, that is, the rotation period for K ignitions, is stored in the memory, and in step 406, the number of ignitions is reset to 0. The processing of steps 400 to 406 is the fourth step.
This is the base step in the figure.

Next, proceed to step 410, calculate the basic advance angle θmap in the same way as step 400, and proceed to step 411.
Now, calculate the target advance angle θ = θmap + θ _B , and then add a predetermined value △t ₁ to this target advance angle θ (that is, advance the target advance angle θ by △t ₁ )
Calculate the ignition timing θ ₂ . In step 412, a control signal corresponding to an ignition timing θa on the more advanced side than the target advance angle θ is generated, and the ignition device 2 causes ignition at θa. Steps 413 and 414 are the same as steps 403 and 404 above, and K
The process is executed in steps 410 to 414. In step 415, the count value K _A (rotation period) of clock pulses for K ignitions is stored in the memory, and in step 416, n=0 as in step 406 above.
shall be. The processing of steps 410 to 416 is the advanced step shown in FIG.

Next, proceed to step 420 and proceed to step 400.
The basic advance angle θmap is calculated in the same way as in (410), and in step 421, the target advance angle θ=θmap+θ _B is calculated, and a predetermined value Δt ₂ is subtracted from this target advance angle θ (that is, the target advance angle θ is △t Retard by _{2〓〓〓〓}
Calculate the ignition timing θr (on the delayed side). In step 422, a control signal corresponding to an ignition timing θr on the retard side than the target advance angle θ is generated, and the ignition device 2 causes ignition at θr. Step 42
3,424 is the step 403,404 (41
3,414), and K times 420 to 424
Execute the steps. In step 425, K
The count value N _R (rotation period) of the clock pulse for ignition is stored in the memory, and in step 426, n=0 as in step 406 (416). The processing of steps 420 to 426 is the litter step shown in FIG.

Next, proceed to steps 430 and 431 and step 4.
Each rotation period N _B obtained at 05, 415, 425,
Compare N _A and N _R . For example, as shown in Fig. 2, when the target ignition timing (target advance angle) θ is on the retard side than the optimum ignition timing θ _M that can maximize the engine output (torque) in the engine state at that time, In addition, when there is no change in the engine operating condition, when ignition is first performed at the target advance angle θ as in the processing steps described above, the rotation period per K ignition times is N _B
The rotation speed (rpm) is a/N _B (where a is a constant)
Then, the ignition timing θa on the advanced side from θ
When ignited, the rotation period is N _A and the rotation speed is a/
N _A , then the ignition timing θ on the retard side from θ
When igniting at r, the same rotation period is N _R and the number of revolutions is a/N _R. As can be seen from Figure 2, comparing the number of revolutions, a/N _R < a/N _B < a/N _A , that is. N _A < N _B < N _R. Therefore, when the relationship N _A <N _B <N _R holds true, this is determined in step 430, and the process proceeds to step 423, where the correction value ΔT ₁ is added to the corrected advance angle θa. In other words, by increasing the corrected advance angle θ _B , the target advance angle θ (= θ _MAP + θ _B )
By adjusting the target advance angle θ to the optimum ignition timing θ _M that maximizes the engine output,
bring it closer. If N _A <N _B <N _R does not hold, the process advances to step 431. For example, when the target ignition timing (advanced angle) θ is on the advanced side of the optimal ignition timing θ _M that can maximize engine output, and when there is no change in the engine operating condition, the case shown in Figure 2 and Conversely, the rotation speed is a/N _A < a/N _B < a/N
_R , that is, N _R <N _B < N _A. Therefore, N _R <N _B <
If N _A is established, this is determined in step 431, and the process proceeds to step 433, where the correction value ΔT ₂ is subtracted from the corrected advance angle θ _B. In other words, by decreasing the modified advance angle θ _B , the target advance angle θ (=θ _MAP +
By correcting θ _B ) to the retarded side, the target advance angle θ is brought closer to the ignition timing θ _M that can maximize engine output. N _A <N _B <N _R or N _R <N _B <N _A
If the relationship does not hold, the process proceeds to step 434 and the corrected advance angle θ _B is not corrected. That is, for example, when the engine operating state changes during a transient period of the engine, if the engine is accelerating, first ignite and operate at the target advance angle θ, then advance the engine by △t ₁ from the target advance angle θ. Even if the engine is operated with ignition at ignition timing θa, and then the ignition is operated with ignition timing θr on the retard (delay) side by △t ₂ from the target advance angle θ, the timing for the target advance angle θ with respect to the optimum ignition timing θ _M Regardless, the rotation speed will increase sequentially, so a/N
Since _B < a/N _A < a/N _R , that is, N _R < N _A < N _B , the determination conditions of steps 430 and 431 are not satisfied, and the corrected advance angle θ _B , that is, the target advance angle θ is not corrected. Similarly, the corrected advance angle θ _B is not corrected even when the engine is decelerating. For example, when the target advance angle θ is at or very close to the optimal ignition timing θ _M and there is no change in the engine operating condition, as can be seen from Fig. 2, the operation with ignition at the target advance angle θ is The rotational speed a/N _B becomes larger than the rotational speed a/N _A , a/N _R of operation with ignition at the advance side ignition timing θa and the retard side ignition timing θr, that is, N _B <N _A , N _B < Since the determination conditions of steps 430 and 431 are not satisfied since N _R , the corrected advance angle _θB, that is, the target advance angle θ is not corrected, but an attempt is made to maintain the target advance angle θ at the optimum ignition timing _θM .

When step 432, 433, or 434 is completed, the process returns to step 400 and the above-described process is repeated. Predetermined values △t ₁ , △ in the above embodiment
t ₂ , the correction values ΔT ₁ and ΔT ₂ and the number of ignitions K are determined by taking into consideration the stability of the engine and the period of the clock pulse for measuring the rotation period for K ignitions.

In the above embodiment, only one corrected advance angle θ _B is rewritten and stored regardless of the engine operating state, but for each engine operating state classification, for example, the basic advance angle θ B is changed in the same manner as the basic advance angle θ map in the above embodiment. It is also possible to create a map and rewrite and store it in large numbers so that the target advance angle θ can quickly converge to the optimum ignition timing θ _M when the operating condition changes such as during engine acceleration or deceleration.

〓〓〓〓
In addition, in the above embodiment, the target advance angle θ is the basic advance angle θ
The basic advance angle θ is calculated by the sum of map and the modified advance angle θ _B.
Map may be set to all zeros. In other words, the basic advance angle θ
Correct the target advance angle θ without using map Advance angle θ _B
It is also possible to just ask for it.

Further, in the above embodiment, the rotation speed when operating at the target advance angle θ, advance side ignition timing θa, and retard side ignition timing θr is determined and compared, and the target advance angle θ is determined.
Although we have determined whether the optimal ignition timing θ _M is on the advanced side or on the delayed side, it is clear that it can be determined not only by the rotation speed but also by engine torque or operating status signals related to these. be.

Further, in the above embodiment, the target advance angle θ, then the advance side ignition timing θa, and then the retard side ignition timing θr.
The engine was operated in this order, and the rotational speed was detected and compared when operating at these three ignition timing points.
In addition, first operate at the target advance angle θ, then at the advance side ignition timing θa, then at the target advance angle θ, then at the retard side ignition timing θr, then at the target advance angle θ, and rotate at 5 points. It is also possible to detect and compare the numbers, and the point is to select at least two ignition timings that are different from each other in the vicinity of the target advance angle θ, including the target advance angle (target ignition timing) θ, and to sequentially and alternately repeat the same. What is necessary is to compare detection signals such as the rotation speed at at least three consecutive points during operation.

As described above, the ignition timing control method of the present invention includes selecting at least two ignition timing points that are close to the target ignition timing and different from each other, and alternately controlling the ignition timing at each of the selected at least two ignition timing points for a predetermined period. Operating the internal combustion engine; detecting the engine speed signal, torque signal, or operating status signal related to these when operating at each of these ignition timings; By comparing the detection signals of at least three consecutive points of the detection signals during operation, it is determined that the target ignition timing is ahead or behind the optimal ignition timing that maximizes the engine output. It is characterized by determining whether the detection signal such as the rotation speed has changed due to external factors such as engine acceleration/deceleration, or whether the detection signal has changed due to a change in the ignition timing. Since the target ignition timing can be controlled to the optimum ignition timing without error, it has the excellent effect of maximizing engine output and minimizing fuel consumption.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a device to which the present invention is applied, FIG. 2 is a characteristic diagram for explaining the operation of the present invention, and FIG. 3 is a schematic diagram of the arithmetic processing contents of the computer shown in FIG. The flowchart shown in FIG. 4 is a time chart for explaining the operation of this computer. 1... Internal combustion engine, 2... Ignition device, 4... Computer. 〓〓〓〓

Claims (1)

[Claims] 1 Selecting at least two ignition timings that are close to the target ignition timing and different from each other; operating the internal combustion engine alternately for a predetermined period at the selected at least two ignition timings; detecting a signal of the rotational speed of the engine, a signal of torque, or a signal of the operating state related thereto when the engine is operated at the ignition timing of the at least two points; By comparing the detection signals at three points during operation, it is determined whether the target ignition timing is on the advance side or behind the optimum ignition timing for maximizing the engine output, and the target ignition timing is corrected. Characteristic ignition timing control method.