JPS5968543A - Control method of internal-combustion engine - Google Patents

Abstract

PURPOSE:To avoid a delay in control, by forecasting a speed based on a measured value stored and maintained in the part, in a digital method control system. CONSTITUTION:An output of a solenoid pickup sensor 302 applies a shaping signal 505 through a wave shape shaping circuit 504. Measured results in relation to the latest two T45Cs in the past are stored in a memory. An arithmetic unit 508 forecasts an engine speed at the time of execution of control by receiving respective data from a measuring device 506 and a memory 507. Based on these forecast results, high voltage is impressed to an ignition plug 514 through an ignition coil 512. A delay in control can be avoided in this manner, in the control of an ignition timing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for controlling an internal combustion engine by an electronic device.
+-! Realizes L) control with virtually no time delay for the time n+J variation of the rotational speed of the internal combustion engine.
This relates to a l-;b il control method.

There is a movement towards electronic control of internal combustion engines (cooperation has been encouraged over the past few years), and control by special gas microcomputers is capable of much more complex control than analog Gil control. , ability to easily respond to design changes, and enhanced timer functions.
The built-in A/D converter allows for a reduction in the number of elements, making it superior to the analog type Ichi++ fin.

When controlling an internal combustion engine using a digital method, the following methods are generally used. That is, a sensor for detecting the operating state such as the rotational speed of the internal combustion engine, and a measuring device such as a counter or A/D converter for converting the operating state into a digital state quantity in response to the output signal of the sensor. , an arithmetic unit that calculates the control amount of the target control item based on the state amount, and a control execution part that executes the control amount, and provides optimal control for the moment-by-moment operating state of the internal combustion engine. Execute. The unavoidable disadvantage in this case is that there is a time delay between detecting the operating state and executing the appropriate control, and especially in internal combustion engines, the operating state fluctuates greatly over time (when the control is executed, This means that the operating state may have changed to a state that is significantly different from that at the time of detection, and that control may no longer be optimal.

This situation is especially true when processing digital quantities.
The above operations such as detection, calculation, and control execution can be processed in parallel, which is made more difficult by the fact that the time delay from detection to control execution increases. In analog control, measurement and calculation or calculation and control execution can be processed in parallel, so it can be said that the control delay mentioned above is under better conditions than in digital control.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to compensate for the detection of a rotational speed, which has a large fluctuation, by taking into account the time delay from the detection of the rotational speed to the control of the controlled object, in a digital control system, and to perform the above-mentioned control. It is an object of the present invention to provide a method of controlling an internal combustion engine that can substantially avoid delays.

The present invention will be explained below with reference to embodiments shown in the drawings.

First, a specific conventional example will be explained with reference to FIGS. 1 and 2. FIG. 1 is a system schematic diagram of internal combustion engine control, taking as an example ignition timing control and ignition coil energization time control for a 4-cycle, 4-cylinder internal combustion engine, and FIG.
It shows the control contents and control timing of the control system shown in the figure.

The rotating parts of the rotor 102 and the power distributor 112 of the rotation sensor are connected to the camshaft of the internal combustion engine by a shaft 101, and the rotational speed thereof is detected by an electromagnetic pickup sensor 103 to know the rotational speed and rotational position of the internal combustion engine. The output of the pickup sensor 103 is shaped by a waveform columnar circuit 104 into an intelligent wave suitable for digital processing. The shaped signal 105 is shown in FIG. 2(a). The shaping signal 105 is 1
The main reference position (for example, top dead center TDC in the example of FIG. 2) of each cylinder occurs every 80'CAC crank angle), and the four sub-reference positions A occur every 45°C in between.

B, C', 1) (TDC) and the time width between each reference position. Here, in order to distinguish between the main reference position and the sub-reference position, another set of rotating rotors and corresponding electromagnetic pickup sensors for main reference position discrimination are actually required, but these are omitted in the figure.

The measuring device 106 constituted by a counter receives the shaped signal 105 and calculates the time width Tl 8 shown in second (b).
0. T90. Measure T45. Main reference position T
180°CA between DC, 90°CA and 45 before main reference position
This is a time width equivalent to 8 degrees Celsius.

Here, we will focus on the operation of the system regarding control in the N region, which is the latest detection period in FIG. 2. Measuring device 1
06 is T18.0 (N-1), T90 in Figure 2 tb)
(N-1) and T45A (Ni) are measured at 6F. The arithmetic unit 107 consisting of a microcomputer or the like receives the measurement result T180 (N-1).

After receiving each data of T90 (N-1) and T45A (N-1), the calculation 20 related to ignition timing control/JLlK201 and energization time control is performed at the position shown in Fig. 2 (C1).
Execute 2. Regarding ignition timing control, first T180
(N-1> is converted into the number of revolutions, and the advance angle or advance time TA(N-1) from the main reference position TDC corresponding to the number of revolutions is
1) Furthermore, in order to determine the ignition timing S by timer control, the time width D from purchase to the ignition timing (side reference position) is determined.
TA = T 45A (N-1) -TA (N
-1) is calculated. Regarding the energization time control, for example, the energization time is set to a constant value TD that does not depend on the rotation speed, and furthermore, in order to determine the energization start time by timer control, the time width TD from the sub-reference position B to the energization start time is set.
l1l=T90 (N 1) TD-TA (N
Calculate I).

The timer device w108 shows the above performance results 1) TA and DT D
The data and timing of the sub-reference positions A and B included in the shaping signal 105 are used to execute the timer processing shown in FIG. Show how you are going,
When the timer value reaches 0, energization is started (0 point) or ignition (8 points) is performed. The ignition timing timer control 204 sets the timer initial value DTA at the sub-reference position A.
This is done by starting a down count and setting the ignition timing S to be after the time DTA. The timer control 203 of the energization start timing is performed by setting the timer initial value D To at the sub-reference position B, starting a down count, and setting the energization start timing to 0 after the time D To.

As a result, the output signal 109 of the timer device 10B becomes as shown in FIG.
The ignition coil 111 is connected to the base of the switching transistor 110 that switches on and off the primary current of the ignition coil 111 at the 0 point.
By starting energizing the primary side and cutting it off at 8 points, a high voltage is generated on the secondary side of the ignition coil 111 and the distributor 1
12, the spark plugs are distributed to spark plug groups 113 of each cylinder of the internal combustion engine.

In this specific example, each measurement result T180 in the N-1 area in FIG.
(N-1), T90 (N-1) and ]゛45A
Arithmetic processing is performed based on (N-1), and the resulting control content is executed in the N area.

Naturally, it is best to use T180 (N), T90 (N), and T45A (N) in the N area to execute control in the N area, but at the time of controlling the N area, the T180 (N) , T90 (N) and T45 (N) are unknown, so it is impossible to perform control based on these data.

As a result, there is a time delay between the measurement of the operating state and the execution of control based on the measurement results, and particularly when the operating state is fluctuating, unexpected control errors occur. In other words, in this specific example, the ignition timing advance time 1 that actually occurs during control execution in the N region of FIG.
゛A' and energization time To' are the required advance time TA (
N) and the energization time TD. However, TA (N
) is the advance time calculated from "I" 180(N).

The actual advance time TA' is: TA'=T45NA(N) T45A(N I)
+TA (N-1) -TA (N) (T45A (N-1)-T4
5A (N)l - (TA (N)TA(Nl))
・1 old... (11. Generally, T45A (N-1) - T45A (N) > TA (N
) 1”A (N -1)・Old... (2), and approximately, TA'DATA (,N) (T45A (N 1
)-T45A (N)l・・・・・・・・・・・・・・・
・(3) becomes. The second term on the right side of equation (3) is the required value TA
(N) represents the error. 1111 error is T4.
This can be said to be the degree of difference between the 81 time measurement of 5A and the time of control execution.

On the other hand, regarding the error in energization time control, T″o′=T
n -fT45B (N-1)-T45B (N)l・
・・・・・・ (41 However, T45B = T 90-T4
It becomes 5A. The second term on the right side of equation (4) represents the error from the required value TD. In other words, it can be said that the error is equal to the difference between the time of T45B measurement and the time of control execution.

The above-mentioned control errors regarding ignition timing and energization time become large values due to rotational fluctuations during sudden acceleration or idling of the internal combustion engine, especially on the low-speed side, resulting in a significant deviation from the expected optimal control. Become.

Next, another embodiment based on the conventional method will be described with reference to FIGS. 3 and 4. Figure 3 shows the control of ignition timing and energization time as in the previous embodiment. FIG. 2 is a schematic diagram of a control system for a four-stroke single-cylinder internal combustion engine that performs ff1l. FIG. 4 shows the control contents and control timing of the control system of FIG. 3. A characteristic difference from the previous embodiment lies in the structure of the rotor of the rotation sensor. The rotor 301 of the rotation sensor is directly connected to the crankshaft of the internal combustion engine, and the electromagnetic pickup sensor 302 generates a pulse with a period of 3 (: 0 'c A. In such a structure, other It is suitable for low-cost systems because it does not require another set of rotation center configurations, but on the other hand, since there is little information about the reference position, the temporal response during rotation fluctuations or sudden acceleration deteriorates.

The output of the electromagnetic pickup sensor 302 is waveform shaped [1
&303, the signal is shaped into a rectangular wave and a shaped signal 304 is output. This shaped signal 304 is shown in FIG. 4 (fl). The shaped signal 304 provides information about the main reference position (TDC), the sub-reference position and the time width between them at every 360°C. Measuring device 305 receives the shaping signal 304 and generates a time width T3 between the main reference positions TDC shown in FIG. 4 (g+).
60 and the time width T between the sub reference position and the main reference position TDC
G measurement processing is performed.

Here, control of ignition timing and energization time in the NIJN region of FIG. 4 will be described. The calculation device 306 is the measurement device 305
After receiving the data of Ta2O(+1-1) and TO(N-1), calculation 401 regarding ignition timing control and calculation 402 regarding energization time control are performed at the position shown in FIG. 4(h).
Do the following. Ta2O(N-1) for ignition timing control
is converted into the number of rotations and the main reference position TDC corresponding to the number of rotations is calculated.
The amount of advance angle from or the advance time corresponding to the amount of advance 'F
A (N-1), and furthermore, data for controlling the ignition timing with a timer device, that is, ignition 1 from the sub reference position.
Time width until 11jJI DTA=TG (N-1)
Calculate TA (N-1).

Regarding the energization time control, the required energization time is set to a constant value '1゛D that does not depend on the rotational speed, and in addition, data for controlling the ignition timing using a timer device, that is, the energization start time from the main reference position TDC, is similarly set. The time width DTo=T3
60 (N 1) Calculate To.

The timer device 307 receives the calculation result DTA.

In response to the data of DTo and the timing of the main reference position TDC and sub-reference position included in the shaping signal 304, the timer control shown in FIG. 4+11 is executed. The ignition timing timer control 404 and the energization start timing timer control 403 determine the ignition timing S and the energization start time 11JIO by operations similar to those in the above-described specific example.

As a result, the output signal 308 of the timer device 307 is shown in FIG.
The secondary voltage generated by the ignition coil 310 is applied to the ignition plug 311 of the internal combustion engine by starting energization of the primary side of the ignition coil 310 at the 0 point and cutting it off at the 8 point. However, among the ignitions that occur every 360° CA, the ignition that corresponds to the exhaust stroke is a waste fire.9 In this specific example, as in the previous specific example, the control in the N region in Fig. 4 is replaced by the measurement in the N-1 region. If rotational fluctuations occur in the internal combustion engine due to a time delay in control that must be performed based on the results, T360 at d1 time
(N-1), TG, (N-1) and T3 during control execution
60 (N) and TG (N), errors occur in the control of ignition timing and energization time.

If we pay particular attention to the control of the energization time, the actual energization time To' during control execution is approximately To'mTo (Ta
2O(N-1) -7360(N) )... (5) It becomes. For example, set the required energization time 'ro to 5 rn s e
'c, and if N -1 (l O00 rpm in the IJi region accelerates to 110 Orpm in the Nll region, the error due to rotational fluctuation shown in the second term of equation (5) will be approximately 5 m5ec. , the actual energization time To' almost disappears, making it impossible to ignite.

The control system shown in Figure 3 is adopted as a low-cost control system because its configuration is very simple.
This embodiment has the disadvantage that malfunctions due to control delays as described above occur more frequently than in the previous embodiments.

Conventional control errors due to control delays are caused by calculating the control amount based on past measurement results themselves.

Therefore, the gist of the present invention is to predict the engine rotational speed that is thought to occur during control execution from the transition of past δ1 measurement results, and to calculate control variables such as ignition timing based on the predicted results. This is an attempt to correct control delays.

A first specific example according to the present invention is illustrated in FIGS. 5 and 6. This specific example is an improved example of FIG. 1 and FIG. The configurations 502, 503 of the rotation sensors, the waveform shaping circuit 504, and its shaping output 505 are the same as those shown in FIG.
``I'90.T45A and T45C immediately after the main reference position TDC for performing prediction operation are measured.The storage device 507 is a characteristic configuration of the present invention,
We store the results of several past plays while updating them one by one.
This is to perform predictive operations based on the state of the transition. In this specific example, the storage device 507 stores the two latest 1s in the past.
”45C measurement results are stored.

For example, to explain the control execution in the N area in FIG. Past trends of T45C from T45C(N-1
) and T45C(N), Figure 6 (rn)
Perform the operation y at the position indicated by . Prediction calculation 601
are the predicted values 〒180 (N), T90 (N), 〒4
Calculate 5A (N). Prediction calculation is acceleration for each ignition.

This is an example of a method in which the state of deceleration is greatly reflected in the transition of T45C.

Calculation 602 related to ignition timing control is T180 (N-1)
, T180 (N) instead of T45A (N-1), 〒4
5A(N), the time width DTA from the sub-reference level purchase to the ignition timing is set as 745A in the same manner as in the conventional embodiment.
(N), calculate TA (glume). Here TA(N)
is the lead angle time calculated based on 7180(N). Calculation 603 related to energization control uses T90 (N) instead of T90 (N-1) and similarly calculates the time width from sub-reference position B to the start of energization DT o =T 90 (N
) Calculate T o. Thereafter, the ignition timing timer control 605 and the energization start timing timer control 604 operate in the same manner as in the above-described specific example.

The operations after the timer device 509 are the same as those in the conventional example shown in FIGS. 1 and 2. That is, the transistor 511 is turned on and off by the output signal 510, and the ignition coil 5121 is turned on and off.
Distributor 513 is started to apply high voltage to spark plug 514 .

Similarly, the ignition timing advance time that actually occurs in the N region'
``8' and the energizing time To' are calculated as TA'~TA (
N) (T45A (N) - T45A (N) 1. , :Gode T45A (N), T4513 (N
) are T45A (N-1) and T45B (N-
Much better than 1)<T45A (N), T45F
(Approximating (N), the required ignition timing advance time TA
(N) and energization time 'D' and the actually occurring advance time TA' and energization time TD' are greatly improved compared to the conventional method. In other words, control is executed by the predictive operation of the present invention. By predicting and correcting the rotational speed of 3141ift, it is possible to substantially eliminate control errors due to time delays from measurement processing to control execution.

Further, a second specific example according to the present invention will be explained with reference to FIGS. 7 and 8. FIG. 7 is a schematic diagram of a control system improved by the present invention over the conventional example shown in FIG. 3, and FIG. 8 shows the control contents and control timing.

Rotation sensor configurations 701 and 702, derived! shape circuit 7
03, the shaped output signal 7o4 (FIG. 8(0)) and the measuring device 705 are the same as those in FIG. 3 of the specific example from IL.

The storage device 706, which is a characteristic configuration of the present invention, stores several past data groups from the present time of the measurement results sequentially sent from the d1 measurement device 705 while updating them one after another. In this specific example, the measurement result T shown in FIG.
The past two measurement results for 360 and TG are stored from the current time, and prediction operations are performed based on the changes in the data.

For example, to explain the control execution in area N in FIG.
-1 area data T360 (N-2), Ta2O (N
-1), TG (N-2).

TG(N-]) is received and calculation is performed at the position shown in FIG. 8(q). A prediction calculation 801 calculates a predicted value 〒36 which is considered to occur in the N area from each of the above data.
0 (N) and 'fc (N).

Kote pays particular attention to the problem of the disappearance of the energization time during sudden acceleration, which was mentioned in the conventional embodiment, and proposes a prediction method to improve this problem as an example.

In other words, a prediction method that prevents the energization time from disappearing during acceleration is Ta6O(N)=T360 (N-1) -+T3
60 (N-2> -T360(N-1)) ・・・・・・・・・・・・ When accelerating 〒360 (N) = T360 (N)... When decelerating, the following relational expression applies. This is one of the easy methods. That is, if it is determined from the past two data that the acceleration condition -Fζ exists, the circumference of 360°cA JIJI Ta2O
Assuming that the phenomenon occurs linearly, the period of the N region 'f360
(N) is determined, and conversely, if there is a deceleration tendency G, the energization time does not decrease, so Ta2O(N) is set to be equal to the previous measurement result of 〒360 (N-1)4.

Calculations related to ignition timing control and energization time control 802゜80
3 is Ta2O (N-1), instead of TG (N-1)'
: f360 (N), 'fc (N) G) - Same as the conventional example described above. In addition, the timer device No. 708 controls the ignition timing and energization start timing.
i control 804. 805. and subsequent signals 709
The operations of the trough 1 fufu 101 ignition coil 11 noah 11 and ignition plug 712 are the same as in the conventional embodiment.

Here, focusing only on the energization time control and similarly finding the actual energization time TD' that occurs in the N region of FIG.
). The problem is that TD' decreases abnormally during acceleration, but since Ta2O(N) is a predicted value in the N region that takes into account the acceleration effect, the amount of decrease in TD' is much greater than in the case of the conventional example. becomes smaller.

That is, by the predictive operation of the present invention, it is possible to prevent a reduction in the energization time during acceleration or, in the worst case, to prevent the energization from disappearing.

The above describes the conventional two-way control using ignition timing and energization time control as an example.
Two specific examples and their respective corresponding specific examples according to the present invention are shown.

However, the scope of application of the present invention is not limited to ignition control of internal combustion engines. Temporal fluctuations in the rotational speed of internal combustion engines are large, and control time delays are also a problem in internal combustion engine control such as fuel quantity control and diesel engine injection timing control. It is possible to apply methods to improve control delays caused by operations.

As described in detail above, the present invention solves the problem of control time delay and resulting deviation from optimal control, which is a problem when using a digital system to control an internal combustion engine whose operating state, particularly rotational speed, fluctuates significantly. and
Predictive operation In other words, the control time is substantially reduced by predicting the value for control execution from past rotational speed trends and determining the ignition timing, fuel amount, and injection timing control amount based on the predicted results. It is possible to eliminate delays and achieve optimal control of the internal combustion engine.

[Brief explanation of the drawing]

FIG. 1 is a system schematic diagram of the first conventional example, FIG. 2 is a timing diagram showing the operation of the conventional example of FIG. 1, FIG. 3 is a system schematic diagram of the second conventional example, and FIG. The figures are a timing diagram showing the operation of the specific example shown in Fig. 3, Fig. 5 is a system schematic diagram of the first embodiment according to the present invention, Fig. 6 is a timing diagram showing the operation of the embodiment shown in Fig. 5, and Fig. 7. is a system schematic diagram of a second embodiment according to the present invention, and FIG. 8 is a timing diagram showing the operation of the embodiment of FIG. 102.301,501.701... Rotor of rotation sensor, 103,302,503,702... Pink up sensor, 104,303,504°703...
Waveform shaping circuit, 106, 305, 506°705...
61 measuring device, 107,306.5 (18°707...
Arithmetic device, 507,706...Storage device, 108.3
07,509,708...Timer device, 110.3
09,511,7]0...Switching transistor, 111,310.512.711...Ignition coil. Representative Patent Attorney Takashi Okabe

Claims (1)

[Claims] +11 A signal representing the rotational speed of the internal combustion engine is detected, the time it takes for the engine to rotate between predetermined reference positions in response to the detection signal is measured, and this measured value is recorded in multiple times in the past. The rotational speed at the time when the engine operating amount is controlled by correcting the latest measured value with a value corresponding to the deviation of the plurality of measured values stored in the memory is predicted. A method for controlling an internal combustion engine, characterized in that the amount of operation of the engine is controlled by Mil based on the rotational speed. (2) The operating amount of the engine is at least one of ignition timing, energization start timing to the ignition coil, supplied fuel amount, or fuel injection timing.
A method for controlling an internal combustion engine as described in . (3) Patent 8/1 characterized in that the period between the predetermined reference positions includes the period between the top dead center of the engine or immediately after the engine's second dead center.
A method for controlling an internal combustion engine according to claim 1 or 2.