JP3507321B2 - Engine idle rotation learning control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine idle rotation learning control device, and more particularly to a device for learning correction of a change in an intake opening area of an engine over time due to dirt or the like.

[0002]

2. Description of the Related Art Contamination due to blowback by EGR, etc. is accumulated on the throttle portion, and even if the throttle is opened by the same amount, the throttle opening area will gradually decrease. A predetermined learning condition was satisfied while introducing an idle air amount learning value corresponding to the amount of dirt accumulated on the engine and performing feedback control of the intake air amount of the engine so that the actual rotational speed approaches the target idle rotational speed during idling. In some cases, the above-mentioned idle air amount learning value is updated based on the feedback correction amount of the idle air amount.

[0003]

By the way, when the vehicle leaves the assembly line in the factory, the idle air amount learning value is calculated for the first time after the engine is first operated, and the learning value is maintained even after the engine is stopped. It is stored so as not to disappear. Then, the product is shipped from the factory in the state of this first learned value.

In this case, since the sliding portion of the engine is not familiar at the beginning of the assembling (the initial friction is large), the amount of air required to maintain the same idle rotation is large. And, the more the operation is continued (the larger the integrated value ADDNE of revolutions from the beginning of assembly is)
This required idle air amount drops sharply and eventually converges to a constant value. Figure 3 shows this process,
As shown in the figure, during the learning in the factory, the required idle air amount has not yet converged, so the learning value calculated in this state changes to the smaller side as the learning progresses.

However, while the required idle air amount sharply decreases, the update rate of the learned value is not so fast that it is delayed in catching up with the actual engine state,
During that time, the learning value becomes excessively large (the idle air amount becomes excessive), and the feedback control center of the idle speed is deviated by the error of the learning value.

Therefore, the present invention determines whether or not the required idle air amount has converged. Before the required idle air amount converges, the idle air amount learning value obtained before the required idle air amount converges is used. The purpose is to prevent the learning value from becoming too large when the engine sliding part is not familiar at the beginning of the assembly by correcting the value to be smaller.

[0007]

As shown in FIG. 6, a first invention provides a throttle valve 21 driven by an actuator 22 and an engine torque steady value according to an accelerator opening and an engine speed. Means 23 for calculating a throttle opening basic value, means 24 for storing a learned value corresponding to a change with time of the opening area of the throttle valve portion,
A means 25 for calculating a feedback correction amount so that the idle speed matches the target idle speed, and the throttle opening basic value is corrected by the feedback correction amount and the learning value to obtain the throttle opening command value. Means 2
6, an engine idle rotation learning control including a means 27 for giving the throttle opening command value to the actuator 22, and a means 28 for updating the learning value based on the feedback correction amount when a learning permission condition is satisfied. In the device, the means 29 for determining whether or not the required idle air amount has converged after the learning value has been updated immediately after the completion of the vehicle assembly, and when it is determined that the required idle air amount has not yet converged, A means 30 for reducing and correcting the learned value updated immediately after the completion of the vehicle assembly is provided.

In the second aspect of the invention, when the integrated value of the engine speed or the vehicle speed from the completion of the vehicle assembly in the first aspect of the invention is less than a predetermined value, it is determined that it is not yet converged.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a determination result as to whether or not convergence has been held is held when the engine is stopped, the battery is replaced, or the engine control ECM is replaced. .

[0010]

According to the first aspect of the invention, considering that the required idle air amount at the time of learning immediately after the completion of the vehicle assembly is larger than that after the shipment, until the required idle air amount converges,
Since we decided to reduce the learning value obtained before the idle air amount converges, the learning value will not become excessively large until the required idle air amount converges.
Therefore, it is possible to prevent the feedback control center of the idle speed from being largely deviated.

Even in the engine in which the required idle air amount has converged, after a situation in which the determination result as to whether or not it has converged is lost when the engine is stopped, the battery is replaced, the engine control ECM is replaced, etc. Although the idle air amount becomes insufficient due to the reduction correction of the learning value while it is determined that it is not converged, the third invention does not cause a situation where the determination result of whether it is before convergence is lost. Therefore, it is possible to prevent erroneous learning due to the loss of the determination result.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, 1 is an engine body, 2 is an intake pipe, 3 is an electronically controlled throttle device driven mainly by a signal from a control unit 11 (mainly a throttle valve 3A and a step motor for driving the throttle valve 3A). 3B).

In the control unit 11, a signal from an accelerator opening sensor (not shown) is converted into an accelerator opening equivalent value, and an engine corresponding to this value and the rotational speed at that time (detected by the engine rotational speed sensor 12). Obtain the steady torque value by searching a predetermined map,
The throttle opening basic value for obtaining this steady torque is calculated, and this throttle opening basic value is given to the step motor 3B which is the actuator of the throttle device 3.

Since a passage for bypassing the throttle valve 3A is not provided, the feedback control of the idle speed, which will be described later, is executed by using the throttle valve 3A.

In addition to the throttle device 3 as described above, the fuel injection valve 4, which is provided so as to directly face the cylinder of each cylinder,
In a cylinder direct fuel injection type spark ignition engine composed of a piston 6 having a cavity formed in consideration of the position of the spark plug 5 on the top surface, a swirl control valve (not shown), etc. Fuel is injected in the latter half of the compression stroke in the load region, etc., thereby forming a combustible mixture in the cavity near the ignition plug 5 near the compression top dead center, and stratifying the fuel with ignition by the ignition plug 5, As a whole, ultra-lean combustion is performed with an air-fuel ratio of over 40.

Further, in the high load region of the engine, fuel is injected in the intake stroke to accelerate the mixing of fuel and air, fill the entire combustion chamber with a homogeneous air-fuel mixture, and perform homogeneous combustion with an air-fuel mixture near the stoichiometric air-fuel ratio. (Homogeneous stoichiometric combustion). Furthermore, in an intermediate load range between the stratified charge combustion region and the homogeneous stoichiometric combustion region, lean combustion (homogeneous lean combustion), which has a richer air-fuel ratio than the stratified combustion but is thinner than the stoichiometric air-fuel ratio, is performed. At times, the fuel is injected in two times, the intake stroke and the compression stroke.

Reference numeral 12 is a crank angle sensor, 13 is an air flow meter, 14 is a water temperature sensor, 15 is an O ₂ sensor, and 16 is a throttle sensor.

Since the dirt due to blowback by EGR is accumulated on the throttle portion and the throttle opening area is reduced with time even if the throttle is opened by the same amount, the dirt amount accumulated with the passage of time. Introducing an idle air amount learning value equivalent to the above, and adding the idle air amount learning value to the above throttle opening basic value as the throttle opening command value, the actual rotation speed during idling There is a method in which the idle air amount learning value is updated based on the feedback correction amount of the idle air amount when a predetermined learning permission condition is satisfied while feedback controlling the intake air amount of the engine so as to approach the rotation speed.

When such conventional idle air amount learning control is directly applied to the in-cylinder direct fuel injection type spark ignition engine, the idle air amount learned value is updated in the state of stratified charge combustion.

However, during stratified charge combustion, the required air amount of the engine is larger than that during homogeneous stoichiometric combustion, and therefore, the ratio of the reduction of the idle air amount due to dirt to the total intake air amount is small, so that the stratified charge combustion is performed. If the idle air amount learning value is updated during combustion, the accuracy of the learning value will decrease.

Therefore, the prior application device (Japanese Patent Application No. 9-1796).
No. 81), learning is performed in a state where the stratified combustion is forcibly switched to the homogeneous stoichiometric combustion when the learning permission condition is satisfied. According to the prior application device, in the state where the homogeneous stoichiometric combustion is switched to, the proportion of the decrease in the intake air amount due to the dirt is large as in the conventional intake air amount, which reduces the accuracy of the learning value. Can be avoided.

When the vehicle leaves the assembly line in the factory, the first idle air amount learning value is calculated after the engine is first operated, and the learning value is stored so as not to disappear even after the engine is stopped. It Then, the product is shipped from the factory in the state of this first learned value.

In this case, since the sliding portion of the engine is not familiar (the initial friction is large) at the beginning of the assembling, the amount of air required to maintain the same idle rotation is large, and as the operation continues, this Although the required idle air amount drops sharply and eventually converges to a constant value (see FIG. 3), the required idle air amount sharply decreases, whereas the learning value update speed is so fast. Since it does not exist, it is delayed in catching up with the actual engine state, the learning value becomes excessively large during that time (the idle air amount becomes excessive), and the feedback control center of the idle speed deviates by the error of the learning value. .

In order to deal with this, in the first embodiment of the present invention, the integrated value ADDN of the number of revolutions from the beginning of the assembling is completed.
When the integrated value of E (or vehicle speed) is less than the predetermined value, it is determined that the required idle air amount is before convergence, and it is predicted that the required idle air amount will eventually settle to a smaller value. The idle air amount learning value obtained before the amount convergence is corrected to the smaller side.

The contents of this control executed by the control unit 11 will be described with reference to FIG.

FIG. 2 is for calculating the idle rotation learning opening TDTVO, which is set at regular intervals (for example, 10 ms).
Every time).

In step 1, it is checked whether or not it is in a steady state.
When all of the following conditions, <1> the rotational speed NE is within a predetermined range, <2> there is no load fluctuation of auxiliary machinery, etc., and <3> the vehicle speed is zero, in a steady state If so, the process proceeds to step 2, and the homogeneous stoichiometric combustion request flag is set to "1" (that is, homogeneous stoichiometric combustion is requested).

When this request flag is received and the previous job has not switched to homogeneous stoichiometric combustion, stratified combustion is switched to homogeneous stoichiometric combustion.

In step 3, it is checked whether the learning permission condition is satisfied. Here, the learning permission condition is <4>
It is in an idle state, <5> the vehicle speed is zero, and <6> the heater fan switch, air conditioner switch, and electric load switch are all off. It is the time of establishment.

When the learning permission condition is satisfied, the routine proceeds to step 4, where the idle air amount learning value QTASEEP1 is calculated. Specifically, the feedback control of the idle speed allows the actual speed NE and the target idle speed NSET to be controlled.
The feedback correction amount of the idle air amount is calculated according to the difference between the feedback correction amount and the feedback correction amount of the idle air amount. A weighted average value of the average value and the idle air amount learning value at the timing when the average value is calculated is updated as a new idle air amount learning value. This idle air amount learning value Q
TASEEP1 is stored in a memory (for example, a flash memory) when the engine is stopped, for example.

Here, the prior application device (in the prior application device, there is no determination of the steady state in step 1, the determination of the learning permission condition of step 3 comes first, and then the stoichiometric request of step 2 follows). In contrast, the fact that steps 1, 2, and 3 are arranged is already disclosed in another application filed at about the same time as the present application. Since it is not directly related to the present invention,
Briefly speaking, when rotation fluctuation occurs due to switching to homogeneous stoichiometric combustion, the above <1> will not hold (that is, will not be in a steady state), and steps 2 and after will be skipped (that is, learning The learning value is not updated even if the permission conditions are met). Then, when the rotation fluctuation accompanying the switching disappears, the process proceeds to step 2 and subsequent steps again, and if the learning permission condition is satisfied, the learning value is updated.

As described above, in the invention of the above-mentioned another application, it is first judged whether or not it is in the steady state before checking whether or not the learning permission condition is satisfied, and when it is in the steady state, the homogeneous stoichiometric request is commanded, and thereafter, Since it is checked whether or not the learning permission condition is satisfied, the learning value does not include the rotational fluctuation due to the switching to the homogeneous stoichiometric combustion, and thus the learning variation can be reduced.

In step 5, the integrated value ADDNE of the engine speed NE after the completion of the vehicle assembly on the assembly line in the factory is compared with the predetermined value GRNE. If the rotational speed integrated value ADDNE is less than the predetermined value GRNE, step 6
Then, the value obtained by subtracting the offset amount TASOFS (constant value) from the idle air amount learning value QTASEEP1 is set again as the idle air amount learning value QTASEEP, thereby correcting the idle air amount learning value. When the rotational speed integrated value ADDNE is equal to or greater than the predetermined value GRNE, the process proceeds from step 5 to step 7 and the idle air amount learning value is not corrected (QTASEEP1 = QTASEEP).
1).

Assuming that the determination value for determining whether or not the required idle air amount has converged is GRNE for the idle air amount, this GRNE is as shown in FIG. Is a slightly larger value than the idle air amount Q0 after convergence (the difference between QAGRN and Q0 is an allowable value), and the rotation speed integrated value ADDNE with respect to this determination value GRNE is the above-mentioned predetermined value GRNE.
From this, when ADDNE <GRNE, the sliding parts of the engine are not familiar at the beginning of the assembly,
Therefore, before the required idle air amount has converged,
If ADDNE ≧ GRNE, it is determined that the sliding portion of the engine has become familiar (the required idle air amount has converged). The parameter used to determine whether or not the required idle air amount has converged is not limited to ADDNE, but may be an integrated value of vehicle speeds from the beginning of assembly.

After the idle air amount learning value is corrected in this manner, the corrected idle air amount learning value QTA is obtained.
SEEP is converted to the throttle opening area learning value ATASLN by multiplying the flow area conversion coefficient CCONVA # in step 8.

Further, in step 9, the throttle opening area learning value ATASLN is converted into the throttle opening using a predetermined table.

The method for converting the throttle opening has already been disclosed in the above-mentioned another application. Since this conversion method itself is not related to the present invention, a brief description will be given with reference to FIG. 4. In FIG. 4, the curve shown is the flow rate characteristic in the initial state.

The throttle opening at the time of updating the learning value is T
Assuming VOM, the throttle opening area AAM (that is, the throttle opening area at the time of updating the learning value) AAM at the intersection of the straight line and the curve which are vertically raised from this TVOM is obtained.

Throttle opening area A at the time of updating the learning value
A value obtained by subtracting ATASLN from AM is obtained as the initial equivalent opening area AAI.

The throttle opening at the intersection of the straight line and the curve drawn horizontally from the initial equivalent opening area AAI is determined as the initial equivalent throttle opening TVOI.

The value obtained by subtracting TVOI from TVOM is the throttle opening corresponding to the throttle opening area learning value ATASLN, which is the idle rotation learning opening TA.
Request as SDTVO.

The idle rotation learning opening TDTVO thus obtained is added to the above-mentioned throttle opening basic value determined according to the accelerator opening and the number of revolutions to obtain the final throttle opening command value. .

In contrast to the correction method by the learning value in the conventional device which moves the broken line characteristic upward in parallel as shown in the middle part of FIG. 5, the correction method by the learning value in the above-mentioned another application is the lower part of FIG. As shown in, the broken line characteristic is translated to the left. In other words, while the conventional device is a system for correcting the air amount (that is, the opening area), the above-mentioned another application is a system for correcting the throttle opening. Comparing the conventional device with the above-mentioned another application, it can be seen that in the above-mentioned another application, the deviation from the flow rate in the initial state is suppressed to be small even if it is far from the point A (learning point). Note that FIG. 5 is an image diagram.

The operation of this embodiment will be described below.

In this embodiment, it is determined whether or not the required idle air amount is before convergence by comparing the integrated value of the rotational speed integrated value ADDNE (or vehicle speed) from the beginning of the assembly with a predetermined value. Until the idle air amount converges, we decided to reduce the learning value obtained before the idle air amount converges, so the learning value is too large until the required idle air amount converges. Therefore, it is possible to prevent the feedback control center of the idle speed from being largely deviated.

By the way, even in the engine in which the required idle air amount has converged, it is determined whether the engine is stopped, the battery is replaced, or the control unit (the engine control ECM) is replaced, before or after the convergence. After the situation where is lost, the idle air amount becomes insufficient due to the correction correction of the learning value while it is determined that it is before the convergence again. Therefore, in order not to lose the judgment result whether it is before convergence or after convergence, the judgment result is lost by storing it in a non-volatile memory (for example, flash memory). It is possible to prevent erroneous learning due to being exposed.

Needless to say, the steps 5, 6, and 7 in FIG. 2 can be applied not only to the prior application apparatus but also to the conventional apparatus.

[Brief description of drawings]

FIG. 1 is a control system diagram of a first embodiment.

FIG. 2 is a flowchart for explaining calculation of an idle rotation learning opening TDTVO.

FIG. 3 is a characteristic diagram of a required idle air amount with respect to a rotation speed integrated value ADDNE.

FIG. 4 is a characteristic diagram for explaining a procedure for converting a throttle opening area learning value ATASLN into a throttle opening.

FIG. 5 is a characteristic diagram showing changes in flow rate characteristics with respect to throttle opening.

FIG. 6 is a diagram corresponding to claims of the first invention.

[Explanation of symbols]

3 Throttle device 4 Fuel injection valve 11 Control unit

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideyuki Tamura Inventor Hideyuki Tamura 2 Takaracho, Kanagawa-ku, Kanagawa Prefecture Nissan Motor Co., Ltd. (72) Inventor Satoru Watanabe 1370 Atsugi, Kanagawa Prefecture Unisia Jecs Co., Ltd. ( 56) References JP-A-8-334047 (JP, A) JP-A-6-93911 (JP, A) JP-A-9-166037 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F02D 41/00-41/40 F02D 9/02 F02D 43/00

Claims (3)

(57) [Claims] 1. A throttle valve driven by an actuator, a means for calculating a throttle opening basic value for obtaining a steady engine torque value according to an accelerator opening and an engine speed, and an opening area of the throttle valve portion. A means for storing a learning value corresponding to a change with time, a means for calculating a feedback correction amount so that the idling speed matches the target idling speed, and the throttle opening based on the feedback correction amount and the learning value. Means for correcting a basic value to obtain a throttle opening command value, means for giving the throttle opening command value to the actuator, and updating the learning value based on the feedback correction amount when a learning permission condition is satisfied. In the engine idle rotation learning control device equipped with the means, A means for determining whether or not the required idle air amount has converged after updating, and a learning value updated immediately after completion of the vehicle assembly when it is determined that the required idle air amount has not converged And an idle rotation learning control device for an engine. 2. The engine idle rotation learning control according to claim 1, wherein when the integrated value of the engine speed or vehicle speed after completion of the vehicle assembly is less than a predetermined value, it is determined that the engine speed has not yet converged. apparatus. 3. The method according to claim 1 or 2, wherein the determination result as to whether or not the convergence is obtained is held when the engine is stopped, the battery is replaced, or the engine control ECM is replaced. Idle rotation learning control device for this engine.