JPS62197670A - Ignition timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To ensure the temperature compensation of an ignition timing by compensating an ignition timing based on a compensation time corresponding to an engine temperature, in a system computing an ignition advance value from data relating to various operating conditions to control an ignition timing. CONSTITUTION:A control unit 10 is inputted signals outputted from operating conditions detecting means such as a load detecting sensor 1 including an air flow meter and the like, a throttle opening rate sensor 3, a cooling water temperature sensor 4 and a rotation angle sensor 5, and computes an ignition advance value to control an igniter 15. In this case, a compensation time is obtained by a predetermined equation or table based on an engine temperature detected by the temperature sensor 4. And, an ignition timing converted from the computed ignition advance value is compensated by the obtained compensation time. Thereby, it is possible to do the temperature compensation of the ignition timing being suitable for the characteristics of the engine from a low speed to a high speed without getting a load to the program excessive.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic ignition timing control device using a microprocessor.

[Conventional technology]

In a spark-ignition internal combustion engine, by selecting the ignition timing so that the cylinder pressure is maximized at a predetermined angle after compression top dead center, the conversion efficiency of C work energy can be increased. Since it takes a certain amount of time for the air-fuel mixture in the air-fuel mixture to be ignited by a spark and for the flame to spread over the entire range, it is possible to advance the ignition angle by increasing the rotational speed, or to reduce the inertness of the air-fuel mixture and residual gas. It is common practice to correct the ignition advance angle according to the density of the fuel.The fire propagation time is also affected by the engine temperature.The ignition timing control device using a microprocessor detects the cooling water temperature. It is possible to correct the ignition timing by using a conventional device that has a table of advance angle correction values according to engine temperature and corrects the ignition advance value (for example, as disclosed in Japanese Patent Application Laid-Open No. 55-139971). ).

However, as shown in Figure 9, if a constant angle correction is made depending on the cooling water temperature regardless of the rotation speed, there is a problem that the angle will be over-advanced in the low rotation range and insufficient in the high rotation range. There was a point. *In addition, in order to obtain advance angle correction values that match the engine requirements from low to high rotations, it is necessary to have a two-dimensional map that corresponds to temperature and rotation speed for water temperature correction.
There was a problem in that the program load on the microprocessor became excessive, making it impractical.

[Problem that the invention seeks to solve]

The present invention has been made to solve the above problems, and provides an internal combustion engine that can perform temperature correction of ignition timing that matches the characteristics of the engine from low rotation to high rotation without increasing the program load. The purpose is to provide an ignition timing control device for Nail.

[Means for solving problems]

Therefore, in the present invention, in an ignition timing control device that calculates an ignition advance value from information related to various operating conditions such as engine speed and load information and controls ignition timing, there is provided a means for detecting a fill temperature, and a means for detecting a fill temperature of the engine. means for determining the correction time based on temperature; 1. There is provided an ignition timing control device for an internal combustion engine, comprising: a correction means for correcting the ignition timing that is changed based on the ignition advance value, using the correction time.

[Effect]

The present invention focuses on the fact that the flame propagation time after ignition depends on temperature. According to the above configuration, the ignition timing is not corrected by a fixed angle corresponding to the engine temperature, but corrected by a fixed time corresponding to the engine temperature, that is, by a correction time.

On the other hand, the main reason why temperature correction of the ignition timing is required is that the flame propagation speed becomes slower when the engine temperature is low. Correction becomes possible. Also,
A fixed correction time corresponds to a small advance angle in the low rotation range and a large advance angle in the high rotation range, so when the correction is made at a constant angle, the angle becomes overadvanced in the low rotation range and in the high rotation range. There is no such thing as a lack of advance angle.

〔Example〕

Embodiments of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a block diagram of an ignition timing control device according to the present invention.

The load detection sensor 1 is an air 70-meter that detects the intake air amount of Ennon, and outputs an analog signal corresponding to the intake air amount. In addition to this, a sensor that detects intake pressure or fuel injection pulse width may be used as the load detection sensor. The battery voltage sensor 2 detects the terminal voltage of a battery, which is a power source for the vehicle, and the throttle opening sensor 3 detects the amount of throttle operation. The cooling water temperature sensor 4 detects the engine temperature based on the cooling water temperature and outputs an analog signal.

The analog signals 15 from each of these sensors 1 to 4 are sent to the A/D converter unit 10 of the single-child control unit 10, converted to digital signals, and sent to the microprocessing unit (MPtJ) 13+2.

The reference angle sensor 6 and the angle sensor 5 are electromagnetic pickup type detectors that are built into the distributor and detect the rotation angle of the crankshaft. The reference angle sensor 6 generates a reference angle signal G at a specific crank angle advanced several degrees from the top dead center of each cylinder, and the angle sensor 5 generates an angle signal Ne every 30° rotation of the crankshaft. The signals from the reference angle sensor 6 and the angle sensor 5 are once input to the input cover 7γ12,
It is sent to the microprocessing unit 13.

In addition to the main device and input buffer 121-, there is also a 7-inch idle switch and a throttle valve. Signals from various switches such as open switch and air conditioner switch are input.

Microbe τI processing unit y) 1311&N Based on the rotation angle information from the angle sensor 6 and the angle sensor 5, and the operating state information from each operating state sensor 1 to 4.7, determines the optimal ignition timing and energization time to the ignition coil. and outputs the ignition signal IGt. Then, by driving the igniter 15 via the output buffer 14 and cutting off the current at one ignition timing when the ignition coil 16 is energized, the high voltage generated when the energization is cut off is sent to a predetermined generous spark plug via the distributor. and ignite each cylinder in sequence.

The microprocessing unit 13 has an output comparison register (OCR;
ister), a current time timer that constantly runs on its own and indicates the current time, a status value that determines whether the ignition signal IGt is set to high level or low level, and whether or not internal interrupts from the output comparison register are enabled. Output control register (TCS) where mask pin (OCF) to be set is set.
R: Tiger ConLrol 5tatus Re
gister). Then, when the value set in the output comparison register (OCR) matches the value of the current time timer, the ignition is started according to whether the status value preset in the output control register (TCSR) is "1" or rOJ. The signal IGt is set to a high level or a low level, and energization to the ignition coil 16 is started or cut off.

At the same time, an internal interrupt request is generated due to a change in the output due to the mask and throat (OCF) settings, and an internal interrupt processing (OCF) is generated.
CI；0output Compare Interru
pt).

FIG. 2 is a timing chart showing the basic processing of ignition control.

For example, in the case of a 4-cycle engine, the reference angle signal G from the reference angle sensor 6 corresponds to 180° rotation of the crank pongee (180°
The angle signal Ne from the angle sensor 5 is input every 30'CA). The angle signal Ne is the reference angle signal G
6 (n10, n+1,..., n+
5) Enter.

External input interrupt processing (ICI processing; Input Capture Interrupt) every time the angle signal Ne is input.
is executed.

Specific angle signal (for example, n+1) before the energization start time
In the ICI processing (C1) at the time of input, a value obtained by adding the current time to the calculated time to start energization is set in the output comparison register (OCR), and the output control register (TCSR) is set to start energization. Status value to be scheduled
1" and a mask bit "1" that enables internal interrupts from the output comparison register.

When the time difference Δt between the output comparison register (OCR) setting value and the current time timer becomes zero and they match, power is started and an internal fflS interrupt is generated due to an internal interrupt request from the output comparison register (OCR). Processing (OCI processing (d
)) is executed. In the OCI process, a value corresponding to the pre-calculated energization time is added to the current time to set the output comparison register (OCR)-2, and a status value r is set in the output control register (TCSR) to schedule the interruption of energization.
Mask bit rOJ, which disables OJ and internal interrupts, is set.

ICI processing at the time of inputting the angle signal (for example n+4) just before the ignition timing! ! ! ! At (C4), a process is performed to reset and correct the set value of the output comparison register (OCR) to a value obtained by adding the current time to the time corresponding to the remaining angle (offset angle) up to the ignition timing.

As a result, since the ignition timing is controlled based on the immediately preceding angle signal, the accuracy of the ignition timing can be ensured.

When the time difference Δt becomes zero and the set value of the output comparison register (OCR) coincides with the current time, the ignition signal IGt is set to a low level, the power supply to the ignition coil 16 is cut off, and ignition is performed. Here, the output control register (TCSR)
Since the mask bit of is set to "O", no internal interrupt occurs.

As described above, the basic processing of ignition control is performed by the timer means including the current time timer and the output comparison register (OCR) within the microprocessing unit 13. This is because it is necessary to interpolate and control between the angle signals Ne generated every 30'' CA.

And, the development of ignition timing according to the present invention! ! Correction based on temperature is performed using the above-mentioned timer means.

By using the timer means, it is possible to perform a reasonable correction that conforms to the essence of temperature correction without increasing the burden on the program.

The actual processing within the microprocessing unit 13 will be explained with reference to the f:tS3 diagram and the 70-chart in @4 diagram.

The processing of the main routine 100 shown in FIG. 3 is always repeatedly executed. In step 101, the rotation speed of the ennon is calculated based on the rotation information from the angle sensor 5 or the reference angle sensor 6 and stored. In step 102, signals from various sensors such as the load detection sensor (intake air amount sensor) 1 and the cooling water temperature sensor 4W1 are read to determine the operating state of the ENON.

Next, in step 103, a pre-stored two-dimensional map is searched and interpolated based on the rotational speed and load information of the Ennon.
The basic ignition timing (advance angle) is calculated based on the engine state at that time. Then, in step 104, the basic ignition timing is slightly corrected based on information from the idle switch, etc., and the target ignition timing is calculated and stored in a predetermined memory.

In the main routine 100, such processing is repeatedly executed, and the target ignition timing is constantly updated according to the operating state at that time.

FIG. 4 is a flowchart showing an interrupt process when the angle signal Ne is input just before the target ignition timing. Angle signal Ne
In the external input interrupt processing (CI processing) for each input, the angular position is first determined, and ICII & filling is executed according to each angle, but these are omitted and not shown here. Further, even if it is immediately before the ignition timing, when the target ignition timing and the immediately preceding angle signal are very close to each other, the immediately preceding angle signal is selected. 70- shown in FIG.
For example, in the example shown in FIG. 2, the chart shows that when the angle signal (n+4) is input, I(, I processing (C4
) is shown.

When an angle signal interrupt occurs at a predetermined angle, first, in step 401, step 10 of the main routine 100 is executed.
The target ignition timing (advance angle) updated and stored in step 4 is loaded into the calculation register. Next, in step 402,
The remaining angle from the current advance angle at the time of occurrence of the interrupt to the target advance angle, that is, the offset angle is calculated. Next, in step 403, the offset angle is converted into the required time based on the rotational speed of the ennon obtained in step 101 of the main routine 100. Step 40 for dogs
4, the value of the current time timer, which is constantly running, is captured and stored.

In step 405, the engine speed, engine load,
Based on engine operating state information such as various switch signals, it is determined whether the current enon state is a condition for water temperature correction. Step 408 if the conditions are not suitable for water temperature correction
Step 4
In addition to the current time stored in step 04, in the next step 409, that value is set in the output comparison register (OCR), and the process ends. As a result, after the required time, that is, at the target ignition timing determined in the main routine 100, the ignition coil 16 is de-energized and ignited.

On the other hand, if it is determined in step 405 that the current engine condition is a condition that requires water temperature correction, step 405
Proceed to step 6. In step 406, the value of the cooling water temperature is captured. In the next step 407, the water temperature correction time is determined from the table based on the cooling water temperature, the water temperature correction time is subtracted from the current time value stored in step 404, and the recorded current time value is updated. and step 4
08, the required time corresponding to the offset angle determined in step 403 is added to the corrected current time value, and in the next step 409, the value is set in the output comparison register (OCR), and the process is terminated.

As a result, the ignition filter 16 is de-energized and ignited at a time when the target ignition timing determined in the main routine 100 is corrected by the water temperature correction time determined in step 407.

FIG. 5 is a characteristic diagram showing the relationship between the cooling water temperature and the water temperature correction time used in step 407. When the cooling water temperature is at a low temperature of 40° C. or lower, the water temperature correction time increases to correct the delay in flame propagation time due to cooling. Furthermore, at high temperatures of 80° C. or higher, the water temperature correction time is slightly increased to advance the water temperature in order to prevent overheating. However, at high temperatures and high loads, the water temperature correction time is set to a negative value, as shown by the broken line, and the ignition advance angle is delayed to prevent knocking.

Although these corrections at high temperatures are not directly related to the delay in flame propagation time, they are also corrected.

Figure 6 is a characteristic diagram of the -5 man hour wi (advance angle) obtained as a result of the correction using the water temperature correction time as described above. Figure 1 shows the relationship between the 6α major advance angle and the Ennon UiJ rolling speed. As shown in Figure 6, which displays the cooling water temperature as a parameter, even if the cooling water temperature is the same, when the rotation speed is high, the ignition advance angle is corrected greatly, and when the rotation speed is low, the ignition advance angle is corrected small, and the ignition advance angle is corrected small when the rotation speed is low. The ignition timing has been corrected to match the characteristics required by the engine at high speeds. This becomes clear when compared with the advance angle characteristic obtained as a result of the conventional constant temperature correction shown in FIG.

As described above, according to this embodiment, water temperature correction corresponding to the rotational speed of the engine can be performed by simply having a one-dimensional table of cooling water temperature and water temperature correction time shown in FIG. y) It is possible to perform water temperature correction that matches the characteristics required by the engine without making the program load of 13 excessive.

In the above embodiment, the explanation has been made assuming that the water temperature correction time table shown in FIG. 5 is independently provided. However, the program load can be further reduced by using tables used for other controls.

- Engine control VcW1, which uses a microprocessing unit in M, often controls not only ignition timing but also fuel injection at the same time.In fuel injection control, the amount of injection is increased to improve driving performance in cold weather. Corrections are being made. For this reason, a table for warm-up increase correction having characteristics as shown in FIG. 7 is provided. By using the calculated value of the warm-up increase 1 correction, adding some calculations, and using it as the water temperature correction time, the program load can be further reduced.

FIG. 8 is a flowchart showing this embodiment. This interrupt process is executed when an angle signal is input just before the α firing timing, and corresponds to FIG. 4 of the above embodiment.

Further, other processes such as the main routine are the same as those in the embodiment described above.In the drawings, steps that perform the same processing as in the embodiment described above are designated by the same reference numerals, and explanations thereof will be omitted.

If it is determined in step 405 that the current engine condition is a condition that requires water temperature correction, step 706
In step 706, the calculated value of the warm-up increase calculated and stored in the process for controlling the injection amount (not shown) is taken into the calculation reno star.6 Next, in step 707
Now, perform a simple calculation such as multiplying the calculated value of the warm-up increase by a certain coefficient to find the correction time corresponding to the cooling water temperature, and then subtract the correction time from the current time value stored in step 404 to create a new value. It is updated and stored as the corrected current Xll value. Then, in step 408, the stored current time value has a required IL value corresponding to an offset angle? In the next step 409, the value is set in the output comparison register (OCR), and the process ends. In this way, temperature correction of the ignition timing can be performed without having a dedicated water temperature correction time table. In addition, in this embodiment, correction is not performed at high temperatures of 80'C or higher as shown in FIG. good,
Even if a table is added, there is an advantage that the program load can be reduced compared to the previous embodiment.

〔Effect of the invention〕

As explained above, the present invention has the above configuration and corrects the ignition timing according to the correction time corresponding to the engine temperature. Therefore, the present invention can adjust the engine speed from low to high speeds without increasing the program load. This has the excellent effect of being able to perform temperature correction on the ignition timing to an ignition advance value that closely matches the characteristics of the engine.

[Brief explanation of drawings]

1 to 8 show embodiments of the present invention, FIG. 1 is a block diagram of an ignition timing control device, FIG. 2 is a timing chart showing basic processing, and FIGS. 3 and 4 are actual Fig. 5 is a characteristic diagram of correction time.
Figure rjS6 is a characteristic diagram showing the ignition advance angle due to water temperature correction, Figure 7 is a characteristic diagram showing warm-up increase correction in fuel injection amount control, Figure m8 is a 70-chart showing the second embodiment, and Figure 9 is The figure is a characteristic diagram showing the ignition advance angle by conventional water temperature correction. 1... Load (intake air amount) detection sensor, 4... Cooling water temperature sensor, 5... Angle sensor, 6... Reference angle sensor,
13...Microbu a processing unit, 15...
・Igniter, 16...Ignition fill. Agent: Patent attorney Isamu Goto □' No. 3 (2)
I Figure 4 10 30
80 (O() Cooling water temperature Engine rotation speed (rpm) Figure 8 Interrupt routine

Claims (1)

[Scope of Claims] 1. In an ignition timing control device that calculates an ignition advance value from information regarding various operating conditions such as engine speed and load information and controls ignition timing, there is provided a means for detecting engine temperature; An ignition timing control device for an internal combustion engine, comprising: means for determining a correction time based on engine temperature; and a correction means for correcting the ignition timing converted from the calculated ignition advance value using the correction time. . 2. The ignition timing control device for an internal combustion engine according to claim 1, wherein the means for determining the correction time is a means for determining the correction time from an engine temperature using a calculation formula or a table. 3. The internal combustion engine according to claim 1, wherein the means for determining the correction time is a means for determining the correction time using a calculated value of warm-up increase correction used to control the fuel injection amount. ignition timing control device.