JPS6050243A - Engine intake-air amount control device - Google Patents

Abstract

PURPOSE:To prevent the engine from leaving the rotational speed thereof being high, by providing an idle judging and compensating means while excludes conditions relating to the rotational speed of the engine, for judging the idle-operating time of the engine just after starting of the engine. CONSTITUTION:There are provided an idle judging means for judging the idle operating time of the engine when the rotational speed of the engine and the opening degree of the throttle valve are below predetermined values, respectively, and a feed-back intake-air control means for carrying out the feed back-control of an intake-air amount regulating means upon idle running. Further, there are provided a starting-time intake-air control means for supplying a predetermined amount of intake-air upon starting of the engine, and an idle judging and compensating means for excluding such a condition that the rotational speed of the engine is below a predetermined value, in order to judge whether the engine is in the idle condition upon starting of the engine or not. With this arrangement, even just after starting of the engine, the engine is prevented from leaving its rotational speed being high.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine intake air amount control device that performs feedback control of the idle speed to a target value.

(Prior Art) Recently, in many automobile engines, feedback control is performed to converge the idle rotation speed to a target value set in consideration of the warm-up state and the like. For this reason, as shown in Japanese Patent Application Laid-Open No. 55-60636, for example, a suction air quick adjustment stage such as a proportional solenoid valve is provided in the bypass air passage that bypasses the throttle valve. Depending on the difference between the number of rotations and the target rotation speed, the intake air 1- flowing through the bypass air passage
I'm trying to adjust it. And, JP-A-54-72
As shown in the No. 319 publication, the above feedback control is performed when at least two conditions are met: the engine speed is below a predetermined value, and the opening degree of the throttle valve is below a predetermined value. Some devices are designed to determine that the vehicle is idling.

Incidentally, when starting an engine, it is common practice to increase the amount of intake air in order to make starting easier. However, in such a device, if the two conditions described above are used to determine whether or not it is idling, the intake air increase 711 at the time of starting will cause the engine rotation speed to be different from that during idling. In some cases, the engine speed does not fall below a predetermined value, which is one of the conditions for making a determination, and this sometimes causes the problem that feedback control is not started and the engine speed remains high immediately after startup. It was happening.

(Purpose of the Invention) The present invention has been made in consideration of the following circumstances.The present invention has been made in consideration of the following circumstances. The main purpose is to provide a control device.

(Structure of the Invention) In order to achieve the above-mentioned object, in the present invention, immediately after starting the engine, it is necessary to determine whether or not the engine is in idle operation, which is a precondition for starting feedback control. , the condition that the engine speed is less than or equal to a predetermined value is excluded.

Specifically, as shown in FIG. 1, as in the past, for example, an intake air amount adjusting means such as a proportional solenoid valve provided with a bypass air passage that bypasses a throttle valve is used, and at least the engine speed is below a predetermined value and 7-stage idle determination for determining that idling operation is occurring when the opening degree of the throttle valve is below a predetermined value; and feedback control of the intake air amount adjusting means to bring the engine speed to a target value of 11 during idling operation. and return intake air control means. The engine includes a starting intake air control means that controls the intake air amount adjusting means to supply a predetermined amount of intake air when starting the engine, and immediately after starting the engine, it determines whether or not the engine is idling. In the determination, an idle determination correcting means is provided which excludes the condition that the engine rotational speed is less than or equal to a predetermined 1.

(Example) In FIG. 2, l is the engine body, and intake air is passed through an intake boat 8 that is opened and closed by an air cleaner 2, an air flow chamber 3, a throttle valve body 4, a surge tank 5, an intake manifold 6, and an intake valve 7. The path from the air cleaner 2 to the intake boat 8 constitutes an intake passage 10. The amount of intake air flowing through this intake passage 10 is controlled by a throttle valve 11 and measured by an air flow meter 12, and this intake air is mixed with fuel injected from a fuel injection valve 13. It has become. Further, the exhaust gas from the combustion chamber 9 is discharged to the atmosphere through an exhaust boat 15, an exhaust manifold 16, etc., which are opened and closed by an antagonism valve 14.

A bypass air passage 17 is attached to the intake passage 10, which has a flow end 17a on the upstream side of the throttle valve 11 and a downstream end 17a thereof.
b are connected to the intake passage 10 on the downstream side of the throttle valve 11, respectively. A solenoid valve 18, which is a proportional solenoid valve, is connected to the bypass air passage 17 as an intake air amount adjusting means.

19 of 21 is a control unit consisting of a microcomputer, and the control unit 22 (19) includes the cooling water temperature as the engine temperature from the water temperature sensor 20, the engine speed from the rotation speed sensor 21, and the idle switch. 22 to determine whether the throttle valve 11 is below a predetermined opening degree (in the embodiment, whether it is fully closed or not)
While the N, 0FF signals and the intake air 111 from the air flow meter 12 are inputted, the control unit I/19 inputs the fuel! l Injection valve 13 and solenoid valve 1
It is designed to be output for 8. In addition, 23 in FIG. 2 is a starter motor, and the starter motor 23 is
It is connected to a battery 25 via a starter switch (starter contact) 24, a of a key switch 24 operated by the person in charge.

The content of control by the control unit 19 will be explained to you based on the flowchart shown in FIG. 3, but explanations of parts not directly related to the present invention, such as $1 fuel injection, will be omitted. In the present embodiment, the music is mainly played during the period when the engine speed is excluded from the idle determination condition immediately after the engine is started, until a predetermined period of time has elapsed after the engine has completely exploded. In addition, in this embodiment, during non-idling operation, feedback control is performed to increase the amount of intake air by a certain amount to the amount of intake air corresponding to one standard rotation speed.
The amount of intake air is controlled in an open manner so that the intake air amount increases, but regardless of whether the feedback control is stable (settled at 11 target rotation speed) or not, the target is to increase the amount of intake air at a certain rate as described in (h). This includes control content to ensure that the amount of intake air corresponds to the rotational speed. Further, the intake air amount is adjusted by adjusting the opening degree of the three-magnetic valve 18, and the opening degree of the solenoid valve 18 is determined according to the duty ratio of the pulse output from the control unit 19. (The larger the duty ratio, the larger the opening degree of the solenoid valve 18).

First, in step 26, it is initialized and
nl is the time T+, and nl is the time T+, which will be described later.
2 is set to 0, the integral duty ratio DI becomes the basic duty ratio DT, and the basic duty ratio DT becomes the set value B(
For example, it is equivalent to 11000 rp).

Next, in step 27, the cooling water temperature, engine speed, and the ON or OFF state from the idle switch 22 are determined.
The FF signal is input as data.

After this, in step 28, based on the cooling water temperature,
During idling operation, the standard revolution speed NT is calculated, and the basic speed corresponding to this II target revolution speed T is calculated. - After the tee ratio DT is calculated in step 29, the process moves to step 30.

1. From step 30 onward, the intake air amount il
J control can be roughly divided into engine startup, immediately after engine startup, and immediately after engine startup, so these will be explained below with reference to FIGS. 4 and 5, but for convenience of explanation, we will We will now explain the control contents immediately after the engine starts (after the region (λ) in FIG. 5) when the problem to be solved by the present invention no longer occurs.

■ Immediately after engine startup In this case, step 30 to step 31, which will be described later.
After 32 and 33, the process moves to step 35. In this step 35, as one condition for determining that the engine is running at idle, it is first determined whether or not the engine speed N is smaller than a predetermined value N. If N is smaller than N, the process moves to step 36. do. In this step 36, as another condition for determining whether or not the vehicle is in idle operation, it is determined whether or not the idle switch 22 is turned on while the throttle valve 11 is in a fully closed state. If the idle switch 22 is ON, this means that all the conditions for determining that the vehicle is in idle operation are satisfied, so feedback control, which will be described later, is performed. In addition, if the engine speed N is greater than the predetermined value No, or in step 3
6, the idle switch 22 is off. When it is determined that the engine is not in idle operation, open control is performed.

Below, the feedback control and open control described in 1- above will be further divided.

During I-1 feedback control, first, in step 37, the integral duty ratio DI is calculated. This integral duty ratio DI corresponds to the previous integral duty ratio DI plus the deviation between the l-1 standard rotational speed N and the current rotational speed N. This is a relation 1 in which the basic duty ratio DT is always outputted to the solenoid valve 18;
This is to correct the deviation.

Next, in step 38, it is determined whether the timer n2 is 0 or not, but since n2=0 has been initialized, the process initially moves to step 39.

In step 39, the basic duty ratio DT is subtracted from the integral duty ratio DI to calculate a duty ratio DTF for use in open control, which will be described later. Then, in step 40, the integral duty ratio D
1 is set as the final duty ratio DW, and this final duty ratio DW is output in step 41. That is, a pulse with a duty ratio that compensates for the deviation between the target rotational speed NT and the current rotational speed N is output to the solenoid valve 18,
:When the arrangement rotation speed N is larger than the 11-mark rotation speed NT,
Bypass air passage 1 by reducing the opening degree of the ゛-L solenoid valve 18
7, the amount of intake air flowing through the bypass air passage 17 is reduced, and conversely, when the number of revolutions N is smaller than the number of revolutions NT of 11, the opening degree of the solenoid valve 18 is increased to increase the amount of intake air flowing through the bypass air passage 17. The air amount is increased, and in this way, the engine speed N is converged to the 11 standard rotation speed NT.

Note that if n2=0 is not determined in step 38, the timer is counted down in step 42, but this step 42 will be described later.

II-2 Open control First, in step 43, it is determined whether n2=0 or not, and if n2-0, the process moves to step 44, where the intake air amount during open control is increased by 1 h. A corresponding duty ratio D0 is set. In addition, this additional amount. is always a constant value.

Next, in step 45, the additional duty ratio D0 is added to the D TPH calculated in step 39 to calculate a corrected duty ratio DM, and then in step 46, the corrected duty ratio DM is added to the corrected duty ratio DM. The duty ratio DI to which the basic duty 2 Ll; DT is added is calculated.

After this, in step 47, 1- duty ratio D
After I is set to the final duty ratio Dw, a timer is set to n2=T2 in step 41, and in step 41, the final duty It D W is set to 'It! , is output to the magnetic valve 18.

In step 43, if n2 is not 20, I'll
If the difference is found, the process moves to step 49, where the basic duty ratio DT is added to the supplementary 11 duty ratio 1'1M.
1, the duty ratio DI increased by 1!1 in step 46 is calculated in step 47.
The final duty ratio is assumed to be the same.

Now, based on FIG. 4, attention will be paid to the time of feedback control, open control, and switching between these times, and -C1 will be further divided. In this Figure 4, the region (+) indicates the state where the feedback control is stable and converged to the 11 frame rotation speed NT, and the regions (2) and (6) indicate the state where the return control is stable and the open control 3. Region (3) represents a state where feedback control has not yet stabilized, and region (4) represents a state where feedback control has transitioned from an unstable state to open control.
) respectively show the transition from open control to feedback control until the feedback control is stabilized.

(b) When transitioning from open control to feedback control, since n2=T2 is set in step 48 during open control, timer n2 is counted down until the corresponding time T2 in which feedback control becomes stable has elapsed. The flow goes from step 38 to step 42, and after this time T2 has elapsed, the flow goes from step 38 to step 39.

(b) When transitioning from a stable state of feedback control to open control, n2=0 in step 43 since the timer has finished counting in step 42.
Therefore, initially steps 43 to 44
It becomes a flow to. Duty ratio DW output at this time
is the duty ratio DI for the deviation from the basic duty ratio DT by 4, plus the duty ratio Do for oven control by 1.
is added, resulting in D I + D o (Step 3
9.45, 46 ijQ). What this DI+Da means is that DI is the deviation from DT.The overall duty ratio output to the electromagnetic jf l B is the difference between the basic duty ratio DT and the open control. 1 minus the duty ratio Do to be multiplied.

Then, from the next time onwards, since the nz-T2 has been set up in step 48 during the initial processing from step 43 to step 44, steps 43 to 49 will be performed from step 43 to step 49.
Initially, in step 46, itu')1. ′
The final duty ratio DI is the final duty It.
; Output as DW.

(c) When transitioning from a state where feedback control is not stable to open control, the timer has not counted down completely in step 42, so 02 in step 43 is not 0, and from step 43 to step 49 It becomes a flow to. At this time, the output duty ratio DW is the duty ratio DM +DT = DI + previously set in step 456.
It becomes Do.

In this way, in this embodiment, regardless of whether the feedback control stably converges to the target value, the duty ratio output during open control, that is, the amount of intake air flowing through the bypass air passage 17, is always , corresponds to the basic duty ratio DT corresponding to the final target value of the feedback control plus an additional amount Do for open control.

When starting the H engine (Fig. 5 area)) In this case, the process moves from step 30 to step 50,
Here, the final duty ratio DW is set as the basic duty ratio DT plus a duty ratio DS (DS > Do) for a predetermined planting addition at the time of starting. Then, this final duty ratio DW is determined in step 51.
After being set to DI in step 41, the output is output to the solenoid valve 18 in step 41, and an amount of intake air corresponding to the final duty ratio DW is supplied. Note that whether or not it is starting is determined when the starter switch 24a is ON (of course, the key 6 switch 24 is ON) and when the engine rotation is fiN.
is lower than the cranking rotation speed Ne of the starter motor 23. Further, the reason why DW is set to DI in step 51 is to change the initial value used to calculate the integral duty ratio DI in step 37 during the feedback control described above.

ff (Immediately after the engine starts (Fig. 5 area (Φ and ■)) When the engine is started with a complete explosion, step 30
Then, the process moves to step 31, and it is determined whether or not the timer nl is O. Initially, n is initialized to be T1, so the process moves to step 52, where timer n is initialized to T1.
1 is counted down, and then the process moves to step 36, where the same process as described in the above-mentioned section (2) is performed. In this case, immediately after starting the engine, even if the throttle valve 11 is fully closed, the engine speed N may not fall below the predetermined value Nn. The condition that the engine speed N is less than or equal to a predetermined value of 7N is excluded from the conditions for determining whether or not the vehicle is in idle cartwheel mode. Therefore, as long as the idle switch 22 is ON, that is, the throttle valve 11 is fully closed, regardless of the engine speed N, the above-mentioned 1. Feedback control is performed, and ]-1 standard rotation speed N
It will converge to T.

Here, in this embodiment, each step of steps 32, 33, and 34 takes into consideration the case where the engine speed N does not decrease to the predetermined value NO even after the timer n1 in step 52 has completely counted down. A step is provided so that the engine speed N is slightly higher than the target speed NT.
Until α is reached, the process proceeds to step 36 without passing through step 35, even if time TI has elapsed. That is, if the engine speed N is not lower than NT0α in step 32, the process moves to step 34, where F (flag) is determined, but since this F has been initialized as 1, step 34 8 to step 36, and skips step 35. Then, when the engine speed N becomes smaller than NT→-α, the process moves from step 32 to step 33, and for the first time, it is determined that the engine speed N is less than the predetermined value No. It is determined whether it is present or not. After passing through step 35, even if the engine speed N becomes larger than NT+α again, the process continues through the route from step 34 to step 35. This means that when the engine speed N reaches NT+α, even if there is some variation in the engine speed N, the engine speed N will be maintained below the predetermined value No, which is the premise for feedback control. This is because it will be done. Note that, normally, the time T is set so that the engine speed N becomes equal to or less than a predetermined value (MNa) after the time TI has elapsed, so steps 32, 33, and 34 of ``1'' are not necessarily required. It is something.

Although eleven embodiments have been described above, the present invention is not limited thereto, and includes, for example, the following cases.

(2) The opening degree of the solenoid valve 18 may be adjusted by changing the cycle of pulses output thereto.

■To adjust the amount of intake air, use a separate bypass air passage 1.
The throttle valve 11 can also be used as an intake air amount adjusting means without providing the throttle valve 7.
This may be done by adjusting the opening degree of.

■The control unit can be configured by either an analog or digital computer.

(Effects of the Invention) The present invention has the following features: 1. As is clear from the above, when determining whether or not the engine is idling, conditions related to the engine speed are excluded immediately after the engine is started. As a result, even if the amount of intake air increases when starting the engine, feedback control to converge the idle speed to the frame speed is reliably performed, resulting in a high zero engine speed. Ichikawa feels like he will be left alone,
The company can certainly do that.

[Brief explanation of the drawing]

Figure 1 shows the overall 4# factors of the present invention. FIG. 2 is an overall system diagram showing one embodiment of the present invention. FIG. 3 is a flowchart showing an example of control contents of the present invention. FIG. 4 and FIG. tB5 are diagrams schematically showing an example of the control contents of the present invention. l...Engine body 17...Input bypass air passage 18...1L magnetic valve 19...No. control unit 21...9 Rotational speed sensor 2211...Idle switch 1

Claims (1)

[Scope of Claims] (+) A rotation speed detection means for detecting the rotation speed of the engine; a throttle opening detection stage 1 for detecting the opening degree of a throttle valve; and the rotation speed detection means and the throttle opening detection means. an idle determination means that receives an output of the engine and determines that continuous idling is occurring when the engine speed is at least a predetermined value or less and the opening degree of the throttle valve is at least a predetermined value or less; and a feedback air intake and air device-f that receives the output of the idle detection stage 1 and controls the intake air amount adjustment means during idle operation to feedback control the engine speed to 11 mark 4tf.
Step by step. Start-up intake air control means for controlling the intake air control means to supply a predetermined amount of intake air suitable for engine start-up 11'; and controlling the idle determination means immediately after engine start-up;
1. An intake air amount control device for an engine, comprising: idle determination correcting means for excluding a condition that the engine rotational speed is a predetermined value or less from an element for determining whether or not the engine is idling.