JPH04314966A - Electronic controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To correctly control ignition timing by installing a phase difference correcting means which corrects a phase difference setting means for setting the aimed ignition timing as phase difference from the first or second crank angle position, on the basis of the detected time interval between both the crank angle positions. CONSTITUTION:A crank angle sensor 2 detects the first crank angle position SGTT and the second crank angle position SGTL on the delayed angle side. A controller 1 calculates the aimed ignition timing of an engine from the detected cycle of SGTT or SGTL. A phase difference setting means sets the aimed ignition timing as the phase difference from SGTT or SGTL. A phase difference correcting means corrects the phase difference setting on the basis of the time interval between SGTL-SGTT. Accordingly, when a detection error is generated between SGTL-SGTT, the ignition timing set at each SGTL or SGTT is corrected so as not to deflect from the aimed ignition timing, and the ignition timing can be controlled correctly.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention detects a first crank angle position SGTT and a second crank angle position SGTL on the advanced side of this in an internal combustion engine, calculates a target ignition timing for each SGTL, This invention relates to an electronic control device for an internal combustion engine that sets the target ignition timing for each SGTL or SGTT depending on conditions.

0002

2. Description of the Related Art Conventionally, this type of electronic control device uses a crank angle sensor disposed in an internal combustion engine (hereinafter simply referred to as the engine) to detect a 4-cylinder internal combustion engine, as shown in FIG. Obtaining crank angle signal. That is, every time the crankshaft rotates 1/2 (180 degrees), a pulsed electrical signal as shown in FIG. 4 is obtained from the crank angle sensor. P1 shown in the figure is the detection point of the first crank angular position SGTT, and P2, which is more advanced than this, is the detection point of the second crank angular position SGTL. In addition, in the same figure, P3 is the top dead center of the engine, and in this example, S
GTT is set at 6 degrees before top dead center, and SGTL is set at 76 degrees before top dead center. Then, the above-mentioned electronic control device measures the SGTL detection period T1 from this crank angle signal,
Based on the engine speed determined from this period T1 and the intake air amount determined from the signal from the air flow sensor, the ignition timing optimal for the operating condition is set as the target ignition timing.
Calculate and set for each TL. Here, if the target ignition timing is set to the retard side than the SGTT, abnormal retardation or abnormal advance may occur due to sudden acceleration or deceleration. In order to prevent this, when the target ignition timing is set to the retard side than SGTT, the target ignition timing is not set from SGTL, and the
It is conceivable to set the target ignition timing from GTT.

0003

[Problems to be Solved by the Invention] However, as mentioned above, the target ignition timing cannot be set for each SGTL or for every SGT depending on the conditions.
If it is set for each GTT, there is a problem that the target ignition timing will shift if there is a detection error between SGTL and SGTT detected by the crank angle sensor. That is, when adjustment is performed based on SGTT, the detection point of SGTL shifts by the amount of error, and when setting the target ignition timing from SGTL, in other words, a timer for generating an ignition signal is set from the detection point of SGTL. In this case, the target ignition timing shifts. In addition, when adjusting based on the SGTL, the detection point of the SGTT shifts by the amount of error, and when setting the target ignition timing from the SGTT, that is, when setting a timer for generating an ignition signal from the detection point of the SGTT, Target ignition timing is off. Note that if the crank angle sensor is precisely machined and accurately detected, it will be possible to eliminate the measurement error between SGTL and SGTT, but this will cause the problem that it will be very expensive.

0004

[Means for Solving the Problems] The present invention has been made to solve such problems, and in the above-mentioned electronic control device, the target ignition timing is corrected based on the detection time interval between SGTL and SGTT. It was designed to do so.

[0005]

[Operation] Therefore, according to this invention, SGTL-SG
If a detection error occurs between TTs, the target ignition timing set for each SGTL or SGTT is
It is corrected based on the detection time interval between SGTTs.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electronic control device for an internal combustion engine according to the present invention will be explained in detail below.

FIG. 1 is a block diagram showing one embodiment of this electronic control device. In the figure, 1 is a control device;
2 is a crank angle sensor, and 3 is an ignition device. The control device 1 includes an input interface 11, an output interface 12, and a microcomputer 13. The input interface 11 shapes the waveform of the signal from the crank angle sensor 2 and supplies it to the microcomputer 13 as a crank angle signal shown in FIG. The output interface 12 receives an ignition signal from the microcomputer 13 and drives the ignition device 3. The microcomputer 13 is a well-known one, and includes a timer 131 and a ROM 1.
32, RAM 133 is included.

FIGS. 2 and 3 show the microcomputer 1
3 is a flowchart for explaining the function of No. 3; The microcomputer 13 executes the flow shown in FIG. 2 in synchronization with the crank angle signal SGTL. That is,
First, in step 201, the period T1 of SGTL is measured. Then, the process proceeds to step 202, where the rotation speed determined from the period T1 and the air flow sensor (not shown) are used.
A map is searched based on the amount of intake air determined by the signal from the engine, and the optimum ignition timing for the driving conditions is determined as the target ignition timing. Then, the process proceeds to step 203, where the ignition timer setting value T2 is calculated. In other words, when the time T2 from SGTL to the target ignition timing is adjusted with the crank angle using SGTL as a reference, the crank angle is adjusted using the following formula (1) using SGTT as a reference. If so, the calculation is performed using the following equation (2). T2=T1×(76°-θ)/180°
...(1) T2=T1×(76°+α−θ
)/180° ... (2) However, in the above formula, θ is the angle from top dead center to the target ignition timing, with the advanced side being positive (+) and the retarded side being negative (-). . Further, in the above formula, α is a detection error (crank angle error) between SGTL and SGTT, and is a value obtained by processing synchronized with SGTT, which will be described later. When adjusting the crank angle based on SGTL, the error α is calculated using the formula (
(1)) is not included. When the crank angle is adjusted based on the SGTT, the error α is included in the calculation equation (Equation (2)).

Next, the process proceeds to step 204, and if the target ignition timing is set to the retard side than SGTT, the SGTT
The timer setting value T0 set at the detection point of SG
When the crank angle is adjusted based on TL, the calculation is performed using the following equation (3), and when the crank angle is adjusted using the SGTT as a reference, the following equation (4) is used. T0=T1×θ1/180°...(3) T0
= T1×θ1/180° (4) However, in the above equation (3), θ1 is 6°-α-θ, 6°-α- If θ≦0, it is set to 0°. In addition, in the above equation (4), θ1 is
If 6゜-θ>0, 6゜-θ, 6゜-θ≦0
In this case, it shall be 0°. In this case, when the crank angle is adjusted based on SGTL, the error α is included in the calculation formula (formula (3)). When adjusting the crank angle based on SGTT, the error α is calculated using the formula ((
4) Not included in formula).

Then, the process proceeds to step 205, and it is determined whether the target ignition timing is set in the zone from the SGTT, that is, whether the timer setting value T0 should be set in the timer 131 at the detection point of the SGTT. Determine. In other words, the target ignition timing is on the retarded side (
θ1>0) and the periodic fluctuation of the crank angle signal is large, and if the timer is set from SGTL, the actual ignition timing will deviate significantly from the target ignition timing. judge. Here, if it is within this zone, the process ends. If not in the zone,
Proceed to step 206 and set the timer setting value T2 to the timer 13.
Set to 1. As a result, the timer 131
After T2 time has elapsed from the L detection point, the ignition signal is output.

Note that the period T1 used in the above equations (1) to (4) may be a period that has been corrected to account for period fluctuations.

Next, the microcomputer 13 executes the flow shown in FIG. 3 in synchronization with the crank angle signal SGTT. First, in step 301, "SGTT
"timer set zone" is determined. The SGTT timer set zone referred to here is the same as the zone described in step 205 in FIG. Here, if it is not within this zone, the process advances to step 303. If it is within the zone, the process advances to step 302. Step 3
In step 02, the timer setting value T0 obtained by the above equation (3) or (4) is set in the timer 131. As a result, the timer 131 starts from T0 from the SGTT detection point.
After the time elapses, an ignition signal is output.

[0013] In step 303, it is determined whether there is a periodic variation. That is, the deviation between the previous cycle and the current cycle in the period between SGTLs is calculated, and if it is less than a predetermined value, it is determined that there is no cycle variation. If there is a periodic variation, the process ends; if not, the process proceeds to step 304. In step 304, S
Calculate the detection time interval TH between GTL and SGTT.

[0014] Then, the process advances to step 305, and the SGTL
The detection error between -SGTT, that is, the crank angle error α, is calculated using the following equation (5). This crank angle error α is used in the above-mentioned SGTL synchronization process. α=(TH/T1)×180°-70°
...(5)

[0015]

As is clear from the above explanation, according to the present invention, when a detection error occurs between SGTL and SGTT, the target ignition timing set for each SGTL or SGTT is changed from SGTL to SGTT. Since the correction is made based on the detection time interval between the two, the ignition timing can be accurately controlled without requiring the crank angle sensor to have strict accuracy.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an electronic control device for an internal combustion engine according to the present invention.

FIG. 2 is a flowchart for explaining processing performed in synchronization with SGTL in this electronic control device.

FIG. 3 is a flowchart for explaining processing performed in synchronization with SGTT in this electronic control device.

FIG. 4 is a diagram showing a crank angle signal.

[Explanation of symbols]

1 Control device 2 Crank angle sensor 3. Ignition device 13. Microcomputer 131 Timer 132 ROM 133 RAM

Claims (1)

[Claims] 1. A first crank angular position SGTT and a second crank angular position SGTL on the advanced side of the first crank angular position SGTT in an internal combustion engine are detected, a target ignition timing is calculated for each SGTL, and the target ignition timing is The SGT according to the conditions
The electronic control device for an internal combustion engine is set for each L or each SGTT, and is characterized by comprising ignition timing correction means for correcting the target ignition timing based on the detection time interval between the SGTL and the SGTT. Electronic control unit for internal combustion engines.