JPH0517401Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an idle control device for an internal combustion engine.

<Prior art> Conventionally, an idle control device has been developed in Japanese Patent Application Laid-Open No. 59-1981 as an idle control device for the purpose of achieving stable idle rotation by reducing rotational fluctuations and engine vibrations during idle due to misfires and strong combustion in internal combustion engines. −51135 Publication,
Techniques disclosed in Japanese Patent Application Laid-open Nos. 61-255273 and 60-256537 are known.

That is, the method described in Japanese Patent Application Laid-Open No. 59-51135 detects the indicated mean effective pressure of each cylinder for each cycle, and calculates the indicated mean effective pressure of each cylinder based on the detected indicated mean effective pressure. The fuel injection amount is controlled so as to approach the arithmetic mean of the indicated mean effective pressures of the cylinders.

What is described in Japanese Patent Application Laid-Open No. 61-255273 is
Each cylinder has its own ignition timing correction value, and the ignition timing is controlled to equalize the explosive power of each cylinder during idling.

Furthermore, the method described in Japanese Patent Application Laid-open No. 60-256537 detects the maximum rotational speed after combustion of the injected fuel for each combustion of the cylinder, and detects the detected maximum rotational speed after combustion. is determined for each cylinder, and the amount of fuel injected and supplied is corrected to increase or decrease for each cylinder so that this value becomes equal between each cylinder.

<Problems to be Solved by the Invention> However, such conventional idle control devices have the following problems.

In other words, the fuel injection amount control method described in JP-A No. 59-51135 uses a combustion pressure sensor to detect the cylinder pressure, resulting in a complicated configuration with multiple combustion pressure sensors, resulting in poor reliability. The problem is that it is difficult to secure.

The ignition timing control described in JP-A-61-255273 and the fuel injection control described in JP-A-60-256537 correct the fuel injection amount, etc. for all cylinders. Since the configuration is such that the rotation fluctuation rate is prevented from deteriorating, there is a problem that the control structure becomes complicated.

In view of the conventional situation, the present invention aims to simplify the configuration by performing increase/decrease correction of fuel injection amount or ignition timing only in specific cylinders for the purpose of preventing rotational fluctuations during idling. With the goal.

<Means for solving the problem> For this reason, the present invention, as shown in the block diagram of FIG. In an internal combustion engine equipped with an ignition device and a fuel injection device, an engine rotation speed detection means detects the engine rotation speed of each cylinder, and an engine rotation speed of each cylinder detected by the engine rotation speed detection means. a first specific cylinder having a high engine rotation speed and a second specific cylinder having a low engine rotation speed based on the cylinder discrimination means; control means for controlling the ignition timing or fuel injection amount for each of the specific cylinder and the second specific cylinder to increase or decrease correction control with respect to the basic control value;
The configuration includes the following.

<Operation> In the above configuration, the engine rotation speed of each cylinder is detected, and based on the detected engine rotation speed of each cylinder, the first specific cylinder with the higher engine rotation speed and the engine rotation speed of the engine rotation speed are selected. A smaller second specific cylinder is discriminated, and based on the discrimination result, the ignition timing or fuel injection amount for each of the first specific cylinder and the second specific cylinder is controlled to increase or decrease with respect to the basic control value. As a result, in the case of ignition timing control, the average effective pressure is restored and the increase is suppressed for the specific cylinder by advancing or delaying the ignition timing, and in the case of fuel injection amount control, by increasing or decreasing the fuel injection amount. , the average effective pressure for each cylinder is equalized.

Note that the control structure does not become complicated and the structure can be simplified, unlike a structure in which the fuel injection amount and the like are corrected for all cylinders individually to prevent the rotation fluctuation rate from worsening.

<Example> Hereinafter, an example of the present invention will be described based on the drawings.

In FIG. 2 showing the configuration of one embodiment, the top dead center signal, 2° crank angle signal, and inflow air amount signal are as follows:
The signals are input from each of the known sensors 1 to 3 to the I/OLSi 5 in the microcomputer 4. In this microcomputer 4, 6 is a CPU, and a RAM 7 and a ROM 8 perform control calculations. Reference numeral 9 denotes a fuel injection device, which injects a specified amount of fuel into each cylinder according to a command from the microcomputer 4. Reference numeral 10 denotes an ignition device, which ignites each cylinder at a specified ignition timing based on instructions from the microcomputer 4.

Here, the fuel injection amount is set by first setting the basic fuel injection amount according to the engine operating state, then detecting the engine rotation speed for each cylinder, and then setting the fuel injection amount based on the detected engine rotation speed for each cylinder. , a first specific cylinder with a high engine rotation speed, and a second specific cylinder with a low engine rotation speed.
Based on the result of this discrimination, the ignition timing or fuel injection amount for each of the first specific cylinder and the second specific cylinder is controlled to increase or decrease with respect to the basic control value. .

Next, the fuel injection amount control routine will be explained according to the flowchart shown in FIG.

In step 1 (denoted as S in the figure), a crank angle signal is inputted from the sensor 2, and in step 2, a top dead center signal of the first cylinder is inputted from the sensor 1. In step 3, it is determined whether or not the top dead center signal has been input. If the top dead center signal has been input (YES), a timer is started in step 4, and the process proceeds to step 5. In step 5, the engine rotation speed is constantly calculated based on the number of clock pulses, and in step 6, it is determined whether or not the engine is idling.If it is idling (YES),
Proceed to step 7, if it is not idle (NO),
Will be returned. In step 7, after the top dead center signal is input, a time corresponding to θ _pnax (crank angle at maximum combustion pressure) of each cylinder is set, for example, for four cylinders, T _1i , T _2i , T _3i , T _4i are respectively It is determined whether or not the rotational speed has been reached, and in step 8, the rotational speed in each cylinder at that time is stored, and in step 9, it is determined whether or not the rotational speed has been sampled a prescribed number of times for each cylinder.

Therefore, when time T _1i is reached after the top dead center signal of the first cylinder is input, the rotational speed of the first cylinder at that time is stored. In this way, first, the rotational speed of the first cylinder is sampled a specified number of times, then similarly, the rotational speed of the third cylinder is stored and sampled a specified number of times, and then the rotational speed of the fourth cylinder is sampled a specified number of times. The rotational speeds of the second cylinders are stored and sampled a prescribed number of times.

Such a specified number of samplings may be, for example, 400
Run the cycle and get it.

If the specified number of samples have been sampled in step 9 (YES), the average value is calculated from each sampled value of the specified number for each cylinder in step 10, and the cylinders with the maximum and minimum rotational speeds are determined from this average value of rotational speeds. . Then, in step 11, the correction amount is subtracted from the basic injection amount for the NMax cylinder determined in step 10, that is, the first specific cylinder, and
The correction amount is added to the basic injection amount for the NMin cylinder, that is, the second specific cylinder. That is, the pulse width (corresponding to the injection amount) of the injection pulse (fuel supply signal) output to the fuel injection device is corrected to increase or decrease, and this is set as the basic injection amount, so various known corrections are made to this. The injection amount is determined, and based on this, the fuel injection device 9 and the ignition device 10 are driven.

In this embodiment, based on the determination result based on the engine rotational speed of each cylinder, the fuel injection amount for the first specific cylinder and the second specific cylinder is controlled to increase or decrease with respect to the basic fuel injection amount. Although only the case where the ignition timing is increased or decreased with respect to the basic ignition timing, that is, the case where the advance/delay correction control is performed, is described based on the flowchart, but the same flow as the flowchart of FIG. 3 is performed.

According to this configuration, the fuel injection amount or ignition timing for the first specific cylinder with a high engine rotation speed and the second specific cylinder with a low engine rotation speed is controlled to increase or decrease with respect to the basic control value. Therefore, in the case of fuel injection amount control, the recovery and rise of the average effective pressure for the specific cylinder is controlled by increasing or decreasing the fuel injection amount, and in the case of ignition timing control, by advancing or delaying the ignition timing. Since the average effective pressure for each cylinder can be made uniform, rotational fluctuations during idling can be suppressed. In particular, for example, the air-fuel ratio is made richer for a second specific cylinder with a lower engine rotational speed, and
By making the air-fuel ratio leaner for a specific cylinder,
The configuration can be simplified without complicating the control structure, unlike a configuration in which the fuel injection amount and the like are individually corrected for all cylinders to prevent deterioration of the rotational fluctuation rate. or,
There is no need to have multiple combustion pressure sensors, and reliability can be easily ensured.

<Effects of the invention> As explained above, according to the invention, by performing increase/decrease correction of the fuel injection amount or ignition timing only in specific cylinders for the purpose of preventing rotational fluctuations during idling, etc. This has a great practical effect of simplifying the configuration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an idle control device for an internal combustion engine according to the present invention, FIG. 2 is a schematic diagram showing an embodiment of the same device, and FIG. 3 is a flowchart illustrating the operation of the same embodiment. 1 to 3...Sensor, 4...Microcomputer, 5...I/OLSi, 6...CPU, 7...
RAM, 8...ROM, 9...Fuel injection device, 1
0...Ignition device.

Claims (1)

[Scope of utility model registration request] In an internal combustion engine equipped with an ignition device and a fuel injection device that output control values for ignition timing and fuel injection amount, respectively, set according to engine operating conditions,
Based on the engine rotation speed detection means for detecting the engine rotation speed of each cylinder, and the engine rotation speed of each cylinder detected by the engine rotation speed detection means,
A cylinder discriminating means for discriminating between a first specific cylinder having a high engine rotational speed and a second specific cylinder having a low engine rotational speed; An idle control device for an internal combustion engine, comprising: control means for controlling the ignition timing or fuel injection amount for each of the second specific cylinders to increase or decrease the basic control value.