JPH04183950A - Idle rotation control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent hunting of engine rotation and improve engine stability by arranging an accidental fire judging means, and carrying out rotation feedback control so as to lower control gain when an engine is fired accidentally. CONSTITUTION:A rotational angular velocity detecting means 4 to detect rotational angular velocity of an internal combustion engine, a throttle opening detecting means 2 and an intake air flow rate detecting means 3 are provided, and the fluctuation width is detected from output signals of the rotational angular velocity detecting means 4 through an accidental fire judging means 6 so that an accidental fire can be judged. Furthermore, according to this accidental fire judgment result and outputs of respective detecting means 2-4, and based on idle rotation speed feedback control gain set beforehand, an idle rotation speed adjusting means 5 is controlled through a control means 7 so that the engine rotation speed can reach target rotation speed, and when an accidental fire condition is detected, feedback control gain is also lowered so that the idle rotation speed adjusting means 5 can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an idle rotation control device for an internal combustion engine.

[Conventional technology]

Conventionally, this type of idle rotation control device measures the rotational speed of an internal combustion engine and adjusts the engine rotation to a predetermined target rotation, as disclosed in, for example, Japanese Patent Laid-Open No. 57-131841. , there is one that performs feedback control with a constant control gain and performs correction control according to atmospheric pressure.

[Problem to be solved by the invention]

However, with such conventional idle rotation control devices,
Since no countermeasures have been taken against misfires, if a certain cylinder misfires and the engine speed fluctuates widely (if this happens, then if control is performed using the normal speed fee I - hack control gain, engine speed will hunt). However, there was a problem in that it caused significant discomfort to the occupants.

The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide an idle rotation control device for an internal combustion engine that can prevent rotation hunting due to engine misfire in idle rotation control. purpose.

[Failure to solve the problem]

The idle rotation control device according to the present invention includes a rotation angular velocity detection means for detecting the rotation angular velocity of an internal combustion engine, and
a throttle opening detection means for detecting the opening of the engine actuator, an intake air flow rate detection means for detecting the intake air flow rate of the engine, and a misfire determination for detecting a fluctuation range from the output signal of the rotational angular velocity detection means to determine a misfire. means, an idle rotation speed adjustment means for adjusting the rotation speed of the internal combustion engine, and an idle rotation speed adjustment means for adjusting the rotation speed of the internal combustion engine; and an idle rotation speed adjustment means for adjusting the rotation speed of the internal combustion engine; Controlling the idle rotation speed adjustment means so that the engine rotation speed becomes a target rotation speed, and controlling the idle rotation speed adjustment means by lowering the foot engine control gain when the misfire determination means detects a misfire condition. System to do? ff11 means.

[Effect]

In the present invention, by providing a misfire determination means and controlling by lowering the idle rotation speed feedback control gain when the engine misfires, it is possible to prevent rotation hunting due to engine misfire.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is a functional block diagram showing the basic configuration of an idle rotation control device according to the present invention, and FIG. 2 is a schematic diagram showing an embodiment when the present invention is applied to an electronically controlled fuel injection type internal combustion engine. be. In FIG. 1, reference numeral 1 denotes an engine as an internal combustion engine to be controlled. Reference numeral 2 denotes a throttle opening detection means for detecting the opening of the throttle actuator 14 shown in FIG. 2, which includes, for example, a throttle position sensor (not shown), the output of which is sent as a throttle opening signal s1 to a control means to be described later. It is being sent out. 3
is an intake air flow rate detection means for detecting the intake air flow rate of the engine I, for example, the air flow meter 12 in FIG.
．． Or throttle position sensor (not shown - scratched)
etc., and the output thereof is sent to the control means as a load signal S3.

4 is a rotational angular velocity detection means of the engine 1, which detects the crank angle signal S detected by the crank angle sensor 19 shown in FIG.
By detecting the rotational angular velocity of the engine by detecting a cycle of each predetermined crank angle from r, an output signal thereof is sent to misfire determining means and control means, which will be described later.

Further, reference numeral 5 denotes an idle speed adjusting means that bypasses the intake passage through which the intake air is adjusted by the throttle actuator 14 shown in FIG. For example, it consists of the idle rotation control actuator 13 shown in FIG. Reference numeral 6 denotes a misfire determining means, which determines a misfire when the difference in rotational angular velocity between two detection sections within one cycle is less than a predetermined value based on the output of the rotational angular velocity detection means 4, and sends its output to the control means. 7, the output of each of the detection means 2 to 4 and the judgment output of the misfire judgment means 6 are large - 5 = control means, and this control means 7 controls the engine using a preset rotation feedback control gain. The idle rotation speed adjustment means 5 is controlled so that the rotation speed becomes the target rotation speed, and when the misfire determination means 6 determines a misfire, the control gain is lowered to adjust the idle rotation speed adjustment means 5 to '+faJ'. ＋It is meant to be sold wholesale.

In addition, in FIG. 2, the control unit 24 is composed of a CPU, etc., and in addition to the idle rotation control by the above-mentioned misfire determination means G, control means 7, etc., it also controls the intake air amount of the engine 1 and its engine rotation, as is generally known. A basic injection pulse corresponding to the intake air amount/rotation speed is calculated by the number, temperature correction is performed by the water temperature sensor 22 to determine the injection pulse, and fuel control is performed by driving the injector 27 with the fuel injection signal S8. Find the optimal ignition signal using the function, fuel injection pulse, and engine speed and select the ignition signal S.
7 has a function of driving the ignition plug 18 and controlling the ignition timing. 11 in Figure 2 is an air cleaner, I
5 is a surge tank, 6 is an intake temperature sensor, 20 is an ignition coil, 21 is an exhaust sensor, and 23 is a cylinder. Further, 82 is an intake air temperature signal output from the intake air temperature sensor 6, S4 is a water temperature signal from the water temperature sensor 22, and Sq is the control unit 1 to 24.
The rotation fee I and hack signals sent to the eye rotation control actuator 13 are shown respectively.

Next, the operation of the present invention will be specifically explained.

Here, Fig. 3 (δH,l) shows the angular velocity state during idle rotation, Fig. 3 fbl shows the angular velocity state when the engine misfires, and Fig. 3 (C) shows the angular velocity state in the state shown in Fig. 3 fa). Figure 3(d) shows the rotational fluctuation in the state shown in Figure 3(b).
FIG. 3(e) shows the rotational pulsation when idle rotation feedback control is performed in the state of fd+ in the figure. With the conventional Zunawara device, even if the engine misfires, Qft hack control is performed using a constant control gain so that the rotation speed reaches the target rotation speed. It exhibited rotational pulsation, and engine rotation did not cause hunting, which was the cause.

Focusing on this point, the present invention was made in order to prevent engine rotation hunting due to engine misfire, as shown in Fig. 4 (8j), and uses flowchart 1 shown in Fig. 5 to reduce idle speed. The rotation control method will be explained.

In FIG. 5, first, when the key switch is turned on and energization is started, the misfire determination flag is reset to O in step 51, and after the engine exits the starting zone, step 52 is executed. At this time, in step 52, the output of the throttle opening detection means 2 and the idle switch (not shown) that detects whether the throttle valve is fully closed determines whether or not the throttle valve 14 is fully closed. and waits until it is fully closed. Then, step 53 is executed when the throttle valve 14 is fully closed. In this step 53, the rotational angular velocity for each predetermined crank angle is detected from the output of the rotational angular velocity detection means 4, and the process proceeds to step 54. In this step 54, if the angular velocity fluctuation width Δω shown in FIG. It is determined that the engine has misfired, and step 55. Step 56 is executed and the misfire flag is set to 7.
Then, the process moves to step 57.

At this time, if no misfire is detected in step 54, the process moves from step 55 to step 57. Further, in step 57, the rotational speed Ne is detected from the output of the rotational angular velocity detection means 4, in step 58, the target rotational speed NO corresponding to the water temperature stored in advance is read, and in step 59, the difference ΔN between Ne and NO is detected. Calculate and find.

Next, step 60 is executed, and the predetermined Δ
The control gain QFB corresponding to ΔN obtained in step 59 is tabled up from the feedback control gain table corresponding to 11, and read into the memory.

Next, step 61 is executed, and it is determined whether or not the misfire flag was set in step 56. If the misfire flag has been set, step 62 is executed. As a result, the predetermined value α is subtracted from the −, Q − −8= control gain QFB read in step 62, the feedback control gain QFB is lowered, and the process proceeds to step 63. Also, if step, pro 1 is negative, continue to step 63
Move to. As a result, in step 63, the drive duty of the idle rotation speed adjusting means 5 is determined, and idle concave rotation foot hack control is performed.

According to this embodiment, when the engine misfires, by lowering the rotation foot hack control gain and controlling the idle rotation speed adjusting means 5, the rotation pulsation is reduced as shown in FIG. 4(b). This makes it possible to prevent engine rotation from hunting.

[Effects of the Invention] As described in 2 below, according to the idle rotation control device of the present invention, a misfire determination means is provided so that when the engine misfires, the control gain is lowered and rotation feedback control is performed. This has the effect of preventing rotational hunting, improving the stability of the engine, and providing a more comfortable ride for the passengers.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing the basic configuration of an idle rotation control device according to the present invention, FIG. 2 is a schematic diagram showing an embodiment of the device according to the present invention, and FIGS. Angular velocity state during idle rotation for explanation. Diagram showing the angular velocity states when the engine misfires, and the rotational fluctuations and rotational drift in those states, Figure 4 F8)
Figure 4 shows the rotational drift when idle rotation feedback control is performed with the conventional normal control gain.
Figure (bl is a diagram showing the rotational drift when controlling by reducing the feedback control gain when a misfire is determined according to the present invention, and Figure 5 is a flowchart for explaining the present invention in detail. .

Claims (1)

[Claims] A rotation angular velocity detection means for detecting the rotation angular velocity of the internal combustion engine, a throttle opening detection means for detecting the opening of the throttle actuator, an intake air flow rate detection means for detecting the intake air flow rate of the engine, and the rotation angular velocity detection means for detecting the rotation angular velocity detection means. misfire determination means for detecting a fluctuation range from the output signal and determining misfire;
An idle rotation speed adjustment means for adjusting the rotation speed of the internal combustion engine, and an engine rotation speed based on a preset idle rotation speed feedback control gain in response to the output of each of the detection means and the determination output of the misfire determination means. control means for controlling the idle rotation speed adjusting means so that the engine speed reaches a target rotation speed, and controlling the idle rotation speed adjusting means by lowering the feedback control gain when the misfire determining means detects a misfire condition; An idle rotation control device for an internal combustion engine, characterized by comprising: