JPH07151043A - Ignition control device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] To enable ignition in a desired ignition timing even during rapid acceleration in an engine that performs ignition control by converting a crank angle into time. [Structure] It is determined whether or not the engine is in a rapid acceleration state based on the amount of change ΔTVO of the throttle valve opening (S1). At times other than during rapid acceleration, the crank angle from the crank angle signal to the ignition timing is converted into time, and ignition is controlled by time measurement (S12 to S14). On the other hand, at the time of sudden acceleration, the in-cylinder pressure P of each cylinder is read (S15), and the in-cylinder pressure P is compared with the reference in-cylinder pressure TARGP corresponding to the desired ignition timing (S1).
6). The actual in-cylinder pressure P is the reference in-cylinder pressure TARGP.
Ignition is controlled on the basis of the fact that the above condition is met (S17).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition control device for an internal combustion engine, and more particularly to a device for controlling ignition timing using a detected value of in-cylinder pressure.

[0002]

2. Description of the Related Art Conventionally, a reference crank angle position (for example, 30 ° CA or TDC cycle) has not been provided with a function of outputting a unit angle signal for each set unit angle of ignition timing (ignition advance value).
As a method of controlling the ignition timing using a crank angle sensor that outputs only a crank angle signal for each, set the time from the detection signal to the desired ignition timing based on the generation cycle of the crank angle signal, A method is known in which the ignition timing is specified based on time measurement and ignition is performed by a spark plug.

That is, in an engine equipped with a crank angle sensor having a function of outputting the unit angle signal, the ignition timing can be directly detected, but when a crank angle sensor which does not output the unit angle signal is used, Since the direct detection cannot be performed, the crank angle is converted into time to specify the ignition timing.

[0004]

However, in the method of setting the time to the ignition timing based on the cycle measurement of the crank angle signal described above, it is considered that the latest measured cycle will continue in the next ignition timing. Is specified based on the time, the ignition is performed at a crank angle position that is significantly different from the desired ignition timing during rapid acceleration of the engine in which the crank angular speed (cycle of the crank angle signal) changes greatly. There was a fear.

The present invention has been made in view of the above problems, and in an engine in which the ignition timing cannot be directly detected as an angle, allows the ignition to be performed at a desired ignition timing even during sudden acceleration. It is an object of the present invention to provide an ignition control device capable of

[0006]

Therefore, an ignition control device for an internal combustion engine according to the present invention is constructed as shown in FIG. In FIG. 1, an in-cylinder pressure detecting means is provided for each cylinder to detect an in-cylinder pressure for each cylinder, and an operating condition detecting means detects an operating condition of the engine.

Here, the reference in-cylinder pressure setting means sets the in-cylinder pressure as a reference for ignition control based on the engine operating condition detected by the operating condition detecting means. The ignition control means compares the reference in-cylinder pressure set by the reference in-cylinder pressure setting means with the in-cylinder pressure for each cylinder detected by the in-cylinder pressure detection means to control the ignition timing by the ignition means. .

[0008]

With this configuration, the in-cylinder pressure as a reference for the ignition control is set based on the engine operating condition, and the ignition timing is based on the comparison result between the reference in-cylinder pressure and the actual in-cylinder pressure detected for each cylinder. Is controlled. That is, the cylinder pressure before ignition during the compression stroke changes substantially uniformly with respect to the crank angle, and the crank angle position can be estimated from the cylinder pressure (see FIG. 5). Instead of giving it as the crank angle, it is given as the in-cylinder pressure, and the ignition timing is specified by whether or not the actual in-cylinder pressure has reached the in-cylinder pressure that is the ignition reference.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 2 showing the configuration of one embodiment, the engine 1 includes an air cleaner 2, an intake duct 3, and a throttle valve 4.
Air is taken in through the intake manifold 5. At the branch portion of the intake manifold 5, a fuel injection valve 6 is provided for each cylinder. The fuel injection valve 6 is an electromagnetic fuel injection valve that is energized by a solenoid to open the valve, and deenergized to close the valve.
Energization is controlled by the drive pulse signal output from 12,
Fuel, which is pumped from a fuel pump (not shown) and adjusted to a predetermined pressure by a pressure regulator, is intermittently injected and supplied.

A spark plug 7 is provided in each combustion chamber of the engine 1.
Is provided, which causes spark ignition to ignite and burn the air-fuel mixture. It should be noted that the ignition plug 7 and an ignition coil, a power transistor, etc., which are not shown, constitute an ignition means in this embodiment. Exhaust gas is discharged from the engine 1 through the exhaust manifold 8, the exhaust duct 9, the three-way catalyst 10, and the muffler 11.

The control unit 12 includes a CPU, RO
A microcomputer including an M, a RAM, an A / D converter, and an input / output interface is provided, which receives input signals from various sensors and determines the fuel injection amount by the fuel injection valve 6 based on the input signals. To control
The ignition timing by the spark plug 7 is controlled. As the various sensors, an air flow meter 13 is provided in the intake duct 3 and outputs a signal according to the intake air amount Q of the engine 1.

Further, a crank angle sensor 14 is provided on the crank shaft or the cam shaft, and in the four-cylinder engine of this embodiment, the crank angle signals REF and # for each compression TDC position (180 ° CA) of each cylinder. A cylinder discrimination signal for each compression TDC position of one cylinder is output to each (see FIG. 5).
The engine speed Ne is calculated by measuring the cycle of the crank angle signal REF.

Further, a water temperature sensor 15 for detecting the cooling water temperature Tw of the water jacket of the engine 1 is provided.
An oxygen sensor 16 that detects the air-fuel ratio of the engine intake air-fuel mixture by detecting the oxygen concentration in the exhaust gas is provided at the collecting portion of the exhaust manifold 8. An in-cylinder pressure sensor 17 as in-cylinder pressure detecting means is attached to each of the spark plugs 7. The in-cylinder pressure sensor 17 has a
As disclosed in Japanese Patent Publication No. 146941, etc., the spark plug 7
The cylinder pressure P of each cylinder is detected as a relative pressure by a piezoelectric element formed as a washer.

The in-cylinder pressure sensor 17 is not limited to the type formed as the washer of the spark plug 7 as described above, but is also disclosed in JP-A-4-8.
As disclosed in Japanese Patent No. 1557 or the like, the pressure sensor may be directly exposed to the combustion chamber. Further, the throttle valve 4 has an opening TV of the throttle valve 4.
A throttle sensor 18 for detecting O is attached.

The ignition timing control by the control unit 12 is performed as shown in the flow charts of FIGS. In this embodiment, the functions of the reference in-cylinder pressure setting means and the ignition control means are the same as those shown in FIG.
Also, as shown in the flowchart of FIG. 4, the control unit 12 is provided as software. Further, in the present embodiment, the air flow meter 13 and the crank angle sensor 14 correspond to operating condition detecting means.

The flowchart of FIG. 3 is designed so that an interrupt is executed in synchronization with the rising edge of the cylinder discrimination signal, and step 1 (S1 in the figure. The same applies hereinafter).
Then, the change amount ΔTVO per unit time of the opening TVO of the throttle valve 4 detected by the throttle sensor 18 is measured. Then, in step 2, the change amount ΔTV
Whether O is equal to or greater than the predetermined value ACC determines whether the engine 1 is in the rapid acceleration state.

Here, the change amount ΔTVO is a predetermined value AC.
If it is less than C and it is determined that the engine 1 is not in the rapid acceleration state, the routine proceeds to step 3, where the ignition timing (ignition advance value) is set in order to perform the time-based ignition control. In step 3, the ignition timing (ignition advance angle) is previously set for each of the operating regions divided into a plurality of engine load equivalent values Tp calculated based on the intake air amount Q and the engine rotation speed Ne, and the engine rotation speed Ne. The ignition timing is determined as the crank angle by referring to the map storing the value).

In the ignition control based on the ignition advance value, first, the cycle of the crank angle signal REF is measured, and the crank angle from the crank angle signal REF to the ignition timing is converted into time T. Then, the time T converted based on the latest cycle measurement result is converted into the latest crank angle signal RE.
The time is measured from F, and the time when the time T has elapsed is regarded as the ignition timing, and the ignition by the spark plug 7 is performed.

By the way, the time-based ignition control as described above can perform ignition at a desired ignition timing during steady operation of the engine 1 in which the cycle of the crank angle signal REF is substantially constant. During the rapid acceleration of the engine 1, the crank angular velocity changes greatly, and even if the time until the ignition timing is set based on the immediately preceding measurement cycle, ignition is performed at an angle position different from the desired ignition timing. There is a fear.

Therefore, when it is determined in step 2 that the engine 1 is in the rapid acceleration operation state, the ignition control based on the in-cylinder pressure detected by the in-cylinder pressure sensor 17 is not performed, and the ignition control based on the in-cylinder pressure sensor 17 is not performed. Is being carried out. When the rapid acceleration state of the engine 1 is determined in step 2, the process proceeds to step 4, and a cylinder corresponding to the desired ignition timing is previously prepared for each of the operating regions divided into a plurality of engine load equivalent values Tp and engine rotation speed Ne. Internal pressure (hereinafter referred to as reference cylinder internal pressure) TAR
The reference cylinder pressure TARGP corresponding to the current operating condition is determined by referring to the map that stores the GP.

That is, the cylinder pressure before ignition (the motoring state) during the compression stroke changes substantially uniformly with respect to the crank angle, and it is possible to estimate the crank angle position from the cylinder pressure. Instead of giving the control reference of the ignition timing corresponding to the condition as the crank angle, it is given as the in-cylinder pressure. The ignition advance value or the reference cylinder pressure TA
The ignition control based on RGP is performed according to the flowchart of FIG.

The flow chart of FIG. 4 is designed so that an interrupt is executed at every predetermined minute time. The minute time is preferably set as a time equal to or shorter than the minimum time required to rotate by 1 ° CA, which is the set unit angle of the ignition advance value. In the flowchart of FIG. 4, first,
In step 11, the opening change amount ΔTVO of the throttle valve 4
The rapid acceleration state of the engine 1 is determined based on the.

When the engine 1 is not in the rapid acceleration state, in step 12, the cycle of the crank angle signal REF is measured,
Next, at step 13, the crank angle from the crank angle signal REF to the ignition timing is converted into time T. Then, in step 14, the time T converted based on the latest cycle measurement result is measured from the latest crank angle signal REF, and the time when the time T has elapsed is regarded as the ignition timing, and the cylinder discrimination signal The ignition by the spark plug 7 is performed in the ignition cylinder determined based on the above.

More specifically, the required energization time is calculated back from the time corresponding to the ignition timing to set the energization start timing to the ignition coil, and the energization start timing and the energization cutoff are measured by measuring the time from the crank angle signal REF. The timing (ignition timing) is controlled. On the other hand, if it is determined in step 11 that the engine 1 is in the rapid acceleration state, the process proceeds to step 15 and the cylinder pressure sensor 17
The in-cylinder pressure P detected by is read.

Next, at step 16, the read in-cylinder pressure P is compared with the reference in-cylinder pressure TARGP set at step 4 of the flow chart of FIG. 3, and the actual in-cylinder pressure P coincides with the reference in-cylinder pressure TARGP. Is determined. In the cylinder in the compression stroke determined by the cylinder determination signal, the time at which the in-cylinder pressure P coincides with the reference in-cylinder pressure TARGP corresponding to the desired ignition advance value while the in-cylinder pressure P increases ( (See FIG. 5), if the actual in-cylinder pressure P matches the reference in-cylinder pressure TARGP, step
Proceeding to 17, ignition by the spark plug 7 of the corresponding cylinder is executed.

As in the case of the time-based ignition control,
It is necessary to control the start of energization to the ignition coil, but in the ignition control using the in-cylinder pressure P, the reference in-cylinder pressure TA corresponding to the ignition timing is set so that the required energization time can be secured.
The reference in-cylinder pressure for starting energization in accordance with the RGP may be variably set in consideration of a margin, or energization may be started at a crank angle position fixed in advance.

In the ignition control using the in-cylinder pressure P as described above, the crank angle position corresponding to the ignition advance position is estimated on the basis of the in-cylinder pressure, so that it is not affected by the change in the crank angular velocity. It is possible to perform ignition at a desired ignition advance position even during rapid acceleration. By the way, when estimating the crank angle position at that time with the in-cylinder pressure as described above, the correlation between the crank angle and the in-cylinder pressure may deviate due to changes over time and individual engine variations. In the operating state, the ignition timing is specified by time measurement, the detected value of the in-cylinder pressure P at that time, and the reference in-cylinder pressure T stored corresponding to the operating condition at that time.
By comparing with ARGP, the reference cylinder pressure TAR
It is advisable to let the GP learn to update.

Further, in the above-described embodiment, the rapid acceleration state and the other states are separately used, and the time-based ignition control and the ignition control using the in-cylinder pressure are separately used. It may be configured to use the ignition control.

[0029]

As described above, according to the present invention, in an engine that cannot directly detect a desired ignition timing as an angle, an in-cylinder pressure set corresponding to the desired ignition timing and an actually detected in-cylinder pressure Since it is configured to control the ignition based on the comparison of, even if the engine is suddenly accelerated,
There is an effect that ignition can be performed at a desired ignition timing.

[Brief description of drawings]

FIG. 1 is a block diagram showing the basic configuration of the present invention.

FIG. 2 is a system schematic diagram showing an embodiment of the present invention.

FIG. 3 is a flowchart showing a state of ignition control according to the embodiment.

FIG. 4 is a flowchart showing a state of ignition control according to the embodiment.

FIG. 5 is a time chart showing the correlation between the crank angle signal and the in-cylinder pressure in the embodiment.

[Explanation of symbols]

 1 Engine 4 Throttle Valve 6 Fuel Injection Valve 7 Spark Plug 12 Control Unit 13 Air Flow Meter 14 Crank Angle Sensor 17 Cylinder Pressure Sensor

Claims (1)

[Claims] 1. An in-cylinder pressure detecting means provided for each cylinder for detecting an in-cylinder pressure for each cylinder, an operating condition detecting means for detecting an operating condition of the engine, and an engine operating condition detected by the operating condition detecting means. A reference in-cylinder pressure setting means for setting an in-cylinder pressure as a reference for ignition control, a reference in-cylinder pressure set by the reference in-cylinder pressure setting means, and an in-cylinder pressure for each cylinder detected by the in-cylinder pressure detection means. An ignition control device for an internal combustion engine, comprising: an ignition control means for controlling the ignition timing of the ignition means by comparing the above with each other.