JPH06280654A - Idle speed control device for engine - Google Patents

Abstract

PURPOSE:To suitably carry out ISC compensation control in accordance with an estimated atmospheric pressure without erroneous learning even through a vehicle shifts from a high land place into a low land place without passing through an atmospheric pressure determining range, in an idle speed control device which indirectly estimates and determines the atmospheric pressure in the atmospheric pressure determining range. CONSTITUTION:An engine idle speed control device comprises idle speed control means 6 for performing learning control and atmospheric compensating control for idle speed adjusting means 5, determining intake-air volume memory means 2, atmospheric pressure determining means 4 for estimating and determining the present atmospheric pressure in accordance with a relationship between a set intake-air volume stored in the memory means 2 and an actual intake-air volume delivered from intake-air volume detecting means 3, atmospheric variation detecting means 7 for detecting a variation in the atmospheric pressure in accordance with an estimated atmospheric pressure, and learning inhibiting means 8 for inhibiting the learning of the idle speed control means upon detection of a large variation in the atmospheric pressure. Learning value resetting means 9 for resetting a learning value in the idle speed control means to a learning value obtained when the atmospheric pressure slightly varies may be used, instead of the learning inhibiting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention indirectly predicts / determines atmospheric pressure information such as an atmospheric pressure value from engine information without using an atmospheric pressure sensor, and according to a change in the atmospheric pressure, ISC.
(Idle Speed Control) The present invention relates to an engine idle speed control device that corrects a control amount.

[0002]

2. Description of the Related Art Conventionally, it is known that an atmospheric pressure is indirectly predicted / determined from engine information without using an atmospheric pressure sensor, and engine control is corrected based on the predicted atmospheric pressure ( See, for example, Japanese Patent Laid-Open No. 1-159447). In this system, an intake air amount map in which the numerical values of the intake air amount corresponding to the operating state of the engine under the standard atmospheric pressure condition are set and stored in advance is provided, and the set reference intake air amount and the actual large amount are set. The atmospheric pressure value at that time is predicted and determined by comparison with the actual intake air amount, which is the detection value of the air flow sensor in the atmospheric pressure state. A bypass passage for supplying intake air to the engine by bypassing the throttle valve of the engine is provided in the intake passage, and the opening of an idle speed control valve (ISC valve) for adjusting the amount of bypass air is set to the atmospheric pressure determination value. I am trying to correct it based on.

[0003]

However, in the above-mentioned prior art, in order to prevent the deterioration of the accuracy of the atmospheric pressure determination, the operation range excluding the engine low speed range and the throttle valve low opening range is excluded from the operation range. The region is set as the atmospheric pressure determination region, and the atmospheric pressure is predicted only in the operating state of the atmospheric pressure determination region. Therefore, in the learning control of the opening of the ISC valve, the region other than the atmospheric pressure determination region is If the altitude changes suddenly during operation, the IS
If the learning control of the C valve is continued, erroneous learning may occur, and the predetermined control may not be performed. For example, as shown in FIG. 8 and FIG. 9, in an operating state in the above-mentioned atmospheric pressure determination region in a highland, and the air density is low based on the atmospheric pressure determination value, the ISC valve is opened to perform the intake amount increase correction. Vehicle is descending on the down road in a driving state in a low opening range other than the atmospheric pressure determination region, reaches a lowland and becomes an idle rotation region (see the same figure), and drives in the low pressure region again in the atmospheric pressure determination region. When the state becomes a state (see the same figure) and the idle rotation region outside the above atmospheric pressure determination region is taken, inconvenience may occur. That is, since the air density increases from the highland to the lowland, the intake air is corrected to the reduced side by the feedback control of the ISC valve. By performing the atmospheric pressure determination in the lowland, the atmospheric pressure determination is performed during the ISC correction control based on the atmospheric pressure determination value in the lowland, from the atmospheric pressure determination region in the highland to the atmospheric pressure determination region in the lowland. It's broken, I
As the learning value for determining the SC control amount, the value based on the atmospheric pressure correction at high altitude (at the time of increasing correction) is retained as it is. Therefore, based on this learning value, the atmospheric pressure predicted value in the lowland If the intake air reduction required by the above is performed, the intake air is excessively reduced based on erroneous learning, and as a result, the amount of bypass air may be insufficient and engine stall may occur.

The present invention has been made in view of such circumstances, and an object of the present invention is to indirectly predict / determine the atmospheric pressure by providing a predetermined atmospheric pressure determination region. Even if the highland changes to the lowland without passing through the atmospheric pressure determination area, the IS based on the atmospheric pressure prediction value
This is to appropriately perform correction control of the C control amount without erroneous learning.

[0005]

In order to achieve the above object, the invention according to claim 1 is, as shown in FIG. 1, an operating state detecting means 1 for detecting an operating state of an engine, and an operating state of the engine. The preset intake air amount for atmospheric pressure determination corresponding to the operating state is stored in the preset atmospheric pressure determination region corresponding to the above, and the set intake air amount is output based on the detected value of the operating state. Air amount storage means 2
From the actual intake air amount detecting means 3 for detecting the actual intake air amount sucked into the engine, the actual intake air amount detected by the actual intake air amount detecting means 3 and the determination intake air amount storage means 2 The atmospheric pressure determining means 4 for determining the atmospheric pressure based on the relationship with the set intake air amount to be output, and the idle speed adjusting means 5 for adjusting the idle speed of the engine are provided with the idle speed as the target speed. And learning control so that the idle rotation speed control means 6 corrects the control amount of the idle rotation speed adjustment means 5 based on the atmospheric pressure determined by the atmospheric pressure determination means 4. Assumption. This apparatus is provided with an atmospheric pressure fluctuation detecting means 7 for detecting the fluctuation state of the atmospheric pressure value judged by the atmospheric pressure judging means 4. Then, when the variation state of the atmospheric pressure value detected by the atmospheric pressure variation detecting means 7 is a large variation, the learning inhibiting means 8 for inhibiting the learning by the idle speed control means 6 is provided. .

According to a second aspect of the present invention, in the first aspect of the invention, the atmospheric pressure fluctuation detecting means 7 is based on the atmospheric pressure value judged by the atmospheric pressure judging means 4,
It is configured to detect the fluctuation state of the atmospheric pressure depending on the magnitude of the deviation between the previous value and the current value of the tampered atmospheric pressure value.

Further, in the invention described in claim 3, when the variation state of the atmospheric pressure value detected by the atmospheric pressure variation detecting means 7 is large variation, instead of the learning inhibiting means 8 in claim 1,
The learning value resetting means 9 for resetting the learning value obtained when the fluctuation state of the atmospheric pressure value is a small fluctuation is provided.

Further, the invention according to claim 4 is the same as claim 3
In the invention described above, the idle speed control means 6 is provided with a learning value for each of various loads acting on the engine. Then, the learned value resetting means 9 is configured to reset all the learned values for each load.

[0009]

With the above construction, in the invention according to claim 1,
The atmospheric pressure fluctuation detecting means 7 detects the fluctuation state of the atmospheric pressure prediction / judgment result in the atmospheric pressure judging means 4, and when the fluctuation state is a large fluctuation, that is, when the atmospheric pressure value suddenly changes, learning is performed. The learning control in the idle speed control means 6 is prohibited by the prohibition means 8. Therefore, in the idle speed control means 6, learning using the control amount based on the atmospheric pressure value before the sudden change is prohibited, and the control amount is corrected based on the atmospheric pressure value after the sudden change. Thereby, for example, from the state where the idle speed control amount is corrected based on the predicted and determined atmospheric pressure value in the operating state of the atmospheric pressure determination region in the highland, the corrected control amount is While being held, the vehicle moved to a lowland in an operating state in a region other than the atmospheric pressure determination region, and in the lowland, the operating state returned to the atmospheric pressure determination region again and the correction control of the control amount based on the atmospheric pressure value was restarted. In this case, erroneous learning due to the correction amount of the control amount based on the atmospheric pressure predicted value (at high altitude) before the sudden change in atmospheric pressure is prevented, and the idle speed control based on this erroneous learning is avoided.

According to the second aspect of the invention, in addition to the operation of the first aspect of the invention, the atmospheric pressure fluctuation detecting means 7 detects the atmospheric pressure fluctuation state by the atmospheric pressure judging means 4. Since it is performed based on the tampered value of itself, that is, on the basis of the deviation between the tampered value of this atmospheric pressure value and the current value, the detection of the sudden change in atmospheric pressure can be performed accurately. Be seen.

According to the third aspect of the present invention, when the fluctuation state of the atmospheric pressure detected by the atmospheric pressure fluctuation detecting means 7 is a large fluctuation, the learning value resetting means 9 makes the fluctuation state of the atmospheric pressure small. It is reset to the learned value obtained at the time of fluctuation. Therefore, in the idle speed control means 6, when the atmospheric pressure value suddenly changes, learning based on the atmospheric pressure correction amount of the idle speed control before the sudden change is not performed, but the learning value at the time of the small fluctuation of the atmospheric pressure fluctuation is used. The control amount is corrected. As a result, as in the case of claim 1, due to an operating state in a region other than the atmospheric pressure determination region, that is, when the highland shifts to the lowland without continuous atmospheric pressure correction, an erroneous The correction control based on the learning value that may be in the learning state is prevented, and the desired idle speed correction control is performed based on the reset learning value when the atmospheric pressure is stable.

Further, according to the invention described in claim 4, in addition to the operation according to the invention described in claim 3, when the judged atmospheric pressure largely fluctuates, the learning value resetting means 9 controls the idle speed. Since all learning values held for each load are reset by the means 6, it is possible to surely prevent erroneous learning in the idle speed correction control.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows an engine to which an engine idle speed control device according to an embodiment of the present invention is applied.
Reference numeral 1 denotes an engine body, which includes a piston 22 that reciprocates in each cylinder formed inside. Reference numeral 23 is a combustion chamber formed above the piston 22 of each cylinder, 24 is an intake passage for supplying intake air to the combustion chamber 23, and 25 is an exhaust passage for discharging exhaust gas from the combustion chamber. Also,
Reference numeral 26 is an intake valve, and 27 is an exhaust valve, which are opened and closed at predetermined timings by a valve mechanism (not shown).

The upstream end of the intake passage 24 communicates with the atmosphere via an air cleaner 28. An air flow sensor 29 as an actual intake air amount detecting means 3 for detecting an intake air amount sucked through the air cleaner 28 is provided in the intake passage 24 at a position downstream of the air cleaner 28. A throttle valve 30 is provided in the intake passage 24 at a position downstream of 29.
Further, an injector 31 for injecting and supplying fuel is provided near the intake port on the downstream end side of the intake passage 24.

Further, the intake passage 24 is provided with a bypass passage 32 connected to an upstream side position and a downstream side position of the throttle valve 30, and the bypass passage 32 bypasses the throttle valve 30. It has become so. An idle speed control valve (ISC valve) 33 is provided in the middle of the bypass passage 32, and the opening degree of the ISC valve 33 is controlled by an idle speed control means (ISC control means) 42, which will be described later, to control the air conditioner. In order to maintain the engine body 1 at a predetermined target idle speed by preventing a decrease in rotation due to a load during operation of a conditioner (hereinafter referred to as A / C), a power steering load, or an electric load during operation of the rear defogger, The increase correction is performed. In addition, the opening degree of the ISC valve 33 is controlled by the ISC control means 42 according to the change in atmospheric pressure (atmospheric pressure correction control). The bypass passage 32 and the ISC valve 33 compose idle speed adjusting means 5.

The control unit 34 includes the air flow sensor 29 and a throttle sensor 35 for detecting the opening of the throttle valve 30 (throttle opening).
And a water temperature sensor 36 provided in the engine body 1 for detecting the temperature of the cooling water, a rotation speed sensor 37 for detecting the rotation speed of the engine, and a transmission system (not shown) for determining whether the gear is in a gear-in state. A neutral sensor 38 for detecting the ON / OFF operation of the A / C, the power steering, or the rear defogger, and the like. 41 and the like are respectively connected. Then, the detected values from the sensors 29, 35 to 38 and the ON / OF from the switches 39, 40 and 41
Based on the F information, learning control of the ISC valve 33 and atmospheric pressure correction control of its control amount (ISC control amount) are performed.

The control unit 34 has the I
In addition to the ISC control means 42 for performing the learning control of the SC valve 33 and the atmospheric pressure correction control, the determination intake air amount memory is used for predicting / determining the atmospheric pressure used for the atmospheric pressure correction control. Means 43 and atmospheric pressure determination for predicting / determining the current atmospheric pressure based on the relationship between the set intake air amount stored in the determination intake air amount storage unit 43 and the actual intake air amount from the air flow sensor 29. And means for detecting a fluctuation state of the atmospheric pressure based on the predicted atmospheric pressure value from the atmospheric pressure determination means 44 as means for performing processing at the time of sudden change in atmospheric pressure. When the fluctuation state of the atmospheric pressure detected by the means 45 and the atmospheric pressure fluctuation detecting means 45 is a large fluctuation (during a sudden change), the learning value 1 described later in the ISC control means 42 is set to the atmospheric pressure stable. A learning value resetting means 46 for resetting the learning value 2 (when the atmospheric pressure is slightly changed) and a learning inhibiting means 47 for inhibiting learning by the ISC control means 42 when the atmospheric pressure is not stable. ing.

The ISC control means 42 opens the ISC valve 33 so that the idle speed becomes a predetermined target idle speed by preventing a decrease in the speed due to each load such as A / C, power steering, or rear defogger. The degree of learning is controlled to perform atmospheric pressure correction based on the atmospheric pressure predicted value from the atmospheric pressure determination means 44. That is, in the highland where the atmospheric pressure is lower than in the lowland, the air density is low, so that the ISC valve 33 is operated to the open side to increase the intake air amount. Is operated to the closing side to reduce and correct the intake air. The ISC control means 42 is adapted to obtain a learning value for each load such as A / C, power steering, or rear defogger. In addition, this learning value is the learning value 1 which is normally used. And a learning value 2 that is used when the atmospheric pressure changes suddenly and is updated only when the atmospheric pressure is small and stable.

The determination intake air amount storage means 43 includes:
As the set intake air amount for atmospheric pressure determination in the predetermined atmospheric pressure determination region, the atmospheric pressure determination region in the above-mentioned atmospheric pressure determination region under the atmospheric pressure condition of a reference lowland (for example, an altitude 0 m point), that is, under the standard condition of air density The reference charging efficiency of intake air in each operating state is preset and stored, and when the operating state is in the atmospheric pressure determination region, the reference charging efficiency corresponding to the operating state is output to the atmospheric pressure determining means 44. It has become.

As shown by the solid line Z in FIG. 3, the above-mentioned atmospheric pressure determination region is the engine speed NE and throttle opening TVO.
The atmospheric pressure determination is performed only when the operating condition defined by the rotational speed NE and the throttle opening TVO is in the atmospheric pressure determination region. That is, the engine speed NE is within a predetermined range (for example, 150) excluding the idle speed range and the high speed range.
0 to 4000 rpm), and the throttle opening TVO has a predetermined range (for example, about 1) excluding the low opening range and the high opening range.
/ 8 opening degree to 5/8 opening degree) is defined as the atmospheric pressure determination area, and the atmospheric pressure determination is prohibited in the operating state in other areas.

Here, the low rotation speed and low opening range are excluded because in FIG. 4 showing the relationship between the throttle opening and the air amount passing through the throttle valve, the throttle opening is in the low opening range of the throttle valve 30. Since the throttle valve passing air amount sharply increases when the opening degree slightly increases, a slight detection error of the throttle opening degree by the throttle sensor 35 appears as a large error of the throttle valve passing air amount and eventually the intake air amount. And on top of that,
In the above low opening range, the ratio of the bypass air amount to the throttle valve passing air amount of the intake air amount is relatively large, and thus the character of the throttle valve passing air amount which should be originally used for the atmospheric pressure determination is different. This is because if the atmospheric pressure determination is performed based on the intake air amount that contains a relatively large amount, the accuracy will be degraded. Further, the high opening range is excluded because in such a region, when the intake air amount is detected by the air flow sensor 29, the intake air amount may be erroneously detected due to the influence of blowback of intake air or the like. Furthermore, the reason why the high rotation speed region is excluded is that a very large amount of intake air is performed in such a region, so that pressure loss occurs due to clogging of the elements of the air cleaner 28, and exhaust gas is exhausted. This is because back pressure may change due to deterioration of the system, and the detection value of the air flow sensor 29 may differ from the actual actual intake air amount.

When the atmospheric pressure determination condition is satisfied, the atmospheric pressure determination means 44 determines the reference charging efficiency output from the determination intake air amount storage means 43 and the intake air output from the air flow sensor 29. The atmospheric pressure value at that time is predicted and determined based on the relationship with the charging efficiency in the operating state at that time, which is obtained from the amount. The atmospheric pressure determination conditions include that the throttle opening TVO and the engine speed NE are in an operating state in the atmospheric pressure determination region, the water temperature THW is in a completely warmed-up state (for example, 80 ° C. or higher), and the transmission system is It is in the gear-in state, and the intake amount increase value at the time of starting is 0, etc., and when all of these conditions are satisfied based on the detection signals from the sensors 35, 37, 36, 38,
It is supposed to be “established”. That is, the atmospheric pressure prediction is executed in a region where there are few error factors and under the condition that the operating state of the engine is in the stable region.

The processing of the atmospheric pressure correction control in the control unit 34 will be described below with reference to FIG.

First, in step S1, the air flow sensor 2
9, the actual intake air amount Qa from 9, the throttle opening TVO from the throttle sensor 35, the engine cooling water temperature THW from the water temperature sensor 36, the engine speed NE from the speed sensor 37, the gear-in information from the gear-in sensor 38, A Input ON / OFF information from 39, 40, 41 such as / C and other information. Then, in an atmospheric pressure prediction routine R1 described later, atmospheric pressure prediction is executed on condition that the atmospheric pressure determination condition is satisfied, and an atmospheric pressure predicted value Calto is obtained.

Next, in step S2, it is determined whether or not the vehicle is continuously downhill, that is, whether or not the vehicle is descending from a highland to a lowland. This continuous downhill determination is performed depending on whether or not the deceleration time continues for a predetermined value or more, that is, the duration time for which the condition that the throttle opening is almost fully closed and the engine speed is 2000 rpm or more is a predetermined value. In the above cases, it is considered a continuous downhill. When it is determined that the slope is a continuous slope, the continuous slope flag is set to 1.

When it is determined in step S2 that the slope is not a continuous downhill slope, the raw atmospheric pressure predicted value C is determined in step S3.
Using the normal value as the reflection rate of alto, the above atmospheric pressure predicted value Cal
Perform the annealing process to to obtain the atmospheric pressure smoothing value Calt,
In step S5, the atmospheric pressure smoothed value Calt is updated as the current value. On the contrary, if it is determined in step S2 that the slope is continuous downhill, the reflection rate is set to 1 (100%) to obtain the atmospheric pressure smoothing value Calt, and this value is calculated in step S2.
The value is updated this time with 5. Above atmospheric pressure normalization value Calt
Is calculated by Calt = Calto (i) * k + Calto (i-1) * (1-k) based on the present value and the previous value of the atmospheric pressure predicted value Calto and the reflection rate k.

Next, in step S6, a sudden change in atmospheric pressure is determined,
That is, it is determined whether or not the atmospheric pressure fluctuation has reached a predetermined large fluctuation state. This sudden change judgment is based on the current value and the previous value of the above-mentioned atmospheric pressure smoothing value Calt, and when Calt (i-1) -Calt (i)> Ch (where Ch is the sudden change judgment value), "atmospheric pressure" It is a sudden change. That is, the determination is made based on whether or not the deviation between the current value and the previous value of the atmospheric pressure smoothed value Calt is larger than a predetermined sudden change determination value Ch.

If it is determined in step S6 that there is a sudden change in atmospheric pressure, the learning value 1 for ISC control for each load such as the A / C that has been used up to then is reset to the learning value 2 in step S7. When it is determined that the atmospheric pressure does not change suddenly, the process proceeds to step S8 and the process proceeds to step S8.

In step S8, the update execution timer for updating the learning value 2 is set, and in step S9, the atmospheric pressure after the sudden change in atmospheric pressure is in a stable state again, that is, the atmospheric pressure fluctuation is a predetermined small fluctuation state. Is determined. This stabilization determination is "atmospheric pressure stable" when Calt-Calto <Ca (Ca is a stabilization determination value) based on the atmospheric pressure predicted value Calto and the atmospheric pressure smoothed value Calt. is there. That is, the determination is made based on whether or not the deviation between the atmospheric pressure predicted value Calto and the atmospheric pressure smoothed value Calt is larger than a predetermined stabilization determination value Ca. Then, if it is determined in step S9 that the atmospheric pressure is not yet stabilized, the process returns and repeats steps S1 to S8. If it is determined that the atmospheric pressure is stable, the process proceeds to step S10, and in this step S10. It is determined whether or not the operating state has passed through the atmospheric pressure determination region (see FIG. 3), that is, whether or not the operating state is outside the atmospheric pressure determination region. If the operating state is within the atmospheric pressure determination region, return Then, the above steps S1 to S
9 is repeated, and if it is outside the atmospheric pressure determination region, the process proceeds to step S11, and in step S11, the update execution timer for the learning value 2 (see step S8) starts counting down.

Then, in step S12, it is determined whether or not the operating state is in the idle region outside the atmospheric pressure determination region. If it is not in the idle region, the process returns and the steps S1 to S11 are repeated to set the idle state. If it is a region, the process proceeds to step S13, and whether or not the update execution timer further counted down in step S13 is continuing the countdown, that is, a relatively short time (for example, 1-2 It is determined whether or not it is within a predetermined time of (minutes). If it is within the predetermined time in step S13, all of the learning value 1 and the learning value 2 for each load are updated and returned in step S14. If the predetermined time has passed, the learning value 1 is set in step S15. Only the update is performed, and the learning value 2 is not updated and the process returns. That is, even after the sudden change in atmospheric pressure, the atmospheric pressure is stabilized again (step S9), and then the operating state in which the predicted atmospheric pressure is not updated (step S10) is still within the predetermined time, the atmospheric pressure is maintained. Learning value 1 by judging that there is no fluctuation
Although 2 and 2 are updated (step S14), since the atmospheric pressure fluctuation may occur if the predetermined time has passed, the learning value 2 is not updated and only the learning value 1 is updated. (Step S15).

The atmospheric pressure fluctuation detecting means 45 is constituted by the steps S2 to S6, and the learning value resetting means 46 is constituted by the step S7. Further, the learning prohibition means 47 is configured by steps S9 to S15. That is, when it is determined in step S9 that the atmospheric pressure is not stabilized, the process returns after step S14,
The learning value update in S15 is prohibited.

In the processing in the atmospheric pressure prediction routine R1, as shown in FIG. 6, first, in step S16, the reference charging efficiency Ceo is input from the determination intake air amount storage means 43, and then in step S17. The air flow sensor 2 within the predetermined time range as the charging efficiency Ce in the current operation
The values obtained by sampling based on the detected values of intake air amount from 9 are integrated and arithmetically averaged. And step S1
At 8, the atmospheric pressure predicted value Calt is set to the above-mentioned standard filling efficiency Ceo,
Based on the current charging efficiency Ce and the coefficient k relating to other air densities such as the intake air temperature, Calt ← (Ce / Ceo) × k is calculated, and this Calt is detected by the ISC control means 42 and the atmospheric pressure fluctuation detection. It is output to the means 45. This atmospheric pressure prediction routine R1 constitutes the atmospheric pressure determination means 44.

Next, the operation and effect of the above embodiment will be described with reference to FIG. The upper part of the figure shows the actual driving state of the vehicle (downhill driving,
The graph shows changes in the altitude change (when the vehicle is stopped), the atmospheric pressure predicted value Calto obtained in response to the altitude change, and the atmospheric pressure smoothed value Calt.

First, a high-altitude vehicle is started from a cold state to start a downhill, the operating state is in the atmospheric pressure determination region, and the atmospheric pressure determination means 44 outputs the atmospheric pressure predicted value Calto. Then, the atmospheric pressure smoothed value Calt is determined and updated based on the normal reflection rate based on the atmospheric pressure predicted value Calto (step S5). In this region, the atmospheric pressure determination is repeated and the atmospheric pressure smoothing value Calt is repeatedly updated, so that it is not determined that the atmospheric pressure is suddenly changed, and only the learning value 2 update timer is set (steps S6 and S8).
At the same time, since the atmospheric pressure is not stabilized, the learning values 1 and 2 are not updated (return from step S9).

Then, when the vehicle decelerates to a stop and enters an idle state, it is outside the atmospheric pressure determination area and Cal at the previous stage.
While t and Calto are held, the ISC learning execution flag is set by the normal idle learning control, and the normal idle learning using the learning value 1 is performed. Then, since the predicted atmospheric pressure value maintains the same altitude, it is determined that the atmospheric pressure is stabilized, the countdown of the learning value 2 update execution timer is started (step S11), and the learning condition is satisfied while the timer continues. The learning value 2 is updated in addition to the learning value 1 (steps S12 to S14), and the timer is reset by this updating.

Next, the descending slope is started again, and during the descending slope, the atmospheric pressure determination region is temporarily operated and the predicted atmospheric pressure Calto is output to obtain the atmospheric smoothing value Calt. Since the atmospheric pressure smoothed value Calt is outside the atmospheric pressure determination region again before it is approximated to the predicted value Calto, a relatively large deviation is maintained between them.

Therefore, even if the vehicle is stopped again and the vehicle is in the idle state and the ISC learning execution flag is set and the vehicle is in the idle learning state, it is not determined that the atmospheric pressure is stabilized, and the learning value 2 is not updated. During this time, in the idle learning of the learning value 1, since the prediction value has not been updated since the previous atmospheric pressure prediction, the slope is descending, and the learning value 1 is updated one after another to compensate for this Becomes

When the descending slope is started again and the operating condition outside the atmospheric pressure determination region continues to become the continuous descending slope condition, Calto and Calt in the previous atmospheric pressure determination are maintained, and the above deviation occurs. Is maintained and updating of the learning values 1 and 2 is prohibited, and the process proceeds. That is, by prohibiting the update of the learning value, it is possible to prevent the erroneous learning from being further increased. Then, when it moves to the lowlands and the operating state becomes in the atmospheric pressure determination region, it is determined that the slope is a continuous downhill.
Since the reflection rate with respect to the atmospheric pressure predicted value Calto is set to 100% (steps S2 and S4), the atmospheric pressure smoothed value Calt coincides with the Calto, and the atmospheric pressure smoothed value Calt held until then suddenly changes. . As a result, it is determined that the atmospheric pressure changes suddenly (step S6), and all the learning values 1 for each load are reset to the learning value 2 (step S7). Therefore, in the ISC control means 42, when the atmospheric pressure value suddenly changes, the correction control of the ISC control amount by the learning value 1 before the sudden change determination is not performed, but the learning value 2 when the atmospheric pressure is stable corrects the ISC control amount. Is done. In this case, unless the learning value 2 is reset, the large correction to the reduction side of the ISC control amount required by the sudden change in atmospheric pressure is performed based on the learning value 1 updated at the time of the idle learning during the previous stop. This means that the bypass air amount from the ISC valve 33 may become insufficient when the vehicle is in an idle state in a lowland, but the occurrence of inconvenience due to such erroneous learning is prevented by resetting to the learning value 2 described above. can do. As a result, even when the vehicle moves from a highland to a lowland in an operating state outside the atmospheric pressure determination area, the ISC control can be reliably made to be a predetermined value, and the idle speed can be surely made the target idle speed. be able to.

Further, in this embodiment, the atmospheric pressure fluctuation detecting means 45 changes the reflection rate of the atmospheric pressure predicted value Calto depending on whether or not there is a continuous downhill slope, and the atmospheric pressure is calculated using this reflection rate. Since the sudden change in atmospheric pressure, that is, the large change in atmospheric pressure is determined based on the value of the difference between the previous value and the current value based on the value Calt, it is necessary to accurately detect the sudden change in atmospheric pressure. You can

Further, the prohibition and reset of the learning values 1 and 2 are carried out for all those which are possessed by each load such as A / C, so that the ISC control can be carried out more reliably.

The present invention is not limited to the above embodiment, but includes various other modifications. That is, in the above embodiment, the learning value 1 is reset to the learning value 2 when the atmospheric pressure suddenly changes (steps S6 and S7; learning value resetting means 46), and the learning values 1 and 2 are prohibited from being updated when the atmospheric pressure is not stabilized. (In the case of NO in step S9;
The learning prohibition means 47) is also used, but the invention is not limited to this, and either one may be adopted, for example.

Further, in the above embodiment, the reference charging efficiency is stored in the determination intake air amount storage means 43, and the current charging determined by the atmospheric pressure determination means 44 from the reference charging efficiency and the detection value of the air flow sensor 29. Although the atmospheric pressure is determined based on the efficiency, the present invention is not limited to this, and the reference intake air amount is stored and set in the determination intake air amount storage means, and this reference intake air amount and the current intake air are determined by the atmospheric pressure determination means. The atmospheric pressure determination may be performed based on the relationship with the air amount.

Further, in the above embodiment, the operating state is grasped by the engine speed and the throttle opening, but the present invention is not limited to this, and it may be grasped by the engine speed and the intake negative pressure, for example.

[0045]

As described above, according to the engine idle speed control device of the present invention, when the atmospheric pressure fluctuation detecting means detects a large fluctuation of the atmospheric pressure, that is, the atmospheric pressure. When the value suddenly changes, the learning control means prohibits the learning control in the idle speed control means. Therefore, in the idle speed control means, learning using a control amount based on the atmospheric pressure value before the sudden change is performed. Is prohibited, and the control amount of the idle speed adjusting means can be corrected based on the atmospheric pressure value after the sudden change. As a result, when operating in a region other than the atmospheric pressure determination region, the highland transitions to a lowland, and in that lowland the operating state returns to the atmospheric pressure determination region and the control amount correction control based on the atmospheric pressure value is restarted. It is possible to prevent erroneous learning in consideration of the amount of control amount correction at high altitude before a sudden change in atmospheric pressure, and based on this erroneous learning, I
SC control can be avoided.

According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, the atmospheric pressure fluctuation detecting means detects the atmospheric pressure fluctuation state and the atmospheric pressure judging means detects the atmospheric pressure value itself. Since it is performed based on the magnitude of the deviation between the previous value and the current value of the atmospheric pressure smoothed value based on the blunted value, it is possible to accurately grasp the sudden change in the atmospheric pressure.

According to the third aspect of the present invention, when a large fluctuation is detected by the atmospheric pressure fluctuation detecting means, the learning value reset means causes the learning value in the idle speed control means to be in a small fluctuation state of the atmospheric pressure, that is, Since the learning value is reset to the learning value obtained in the stable state, the idle speed control means prevents the correction control based on the learning value that may be in the erroneous learning state when the atmospheric pressure value suddenly changes. The desired idle speed correction control can be performed based on the reset learning value when the atmospheric pressure is stable.

Further, according to the invention described in claim 4, in addition to the effect of the invention described in claim 3, when the atmospheric pressure fluctuates greatly, the learning value resetting means causes the idle rotation speed control means to control each load. Since all the learned values that are held are reset every time, it is possible to reliably perform the correction control of the idle speed.

[Brief description of drawings]

FIG. 1 is a block diagram showing the present invention.

FIG. 2 is a schematic configuration diagram of an engine to which an embodiment of the present invention is applied.

FIG. 3 is a relationship diagram between an operating state and an atmospheric pressure determination region.

FIG. 4 is a relationship diagram between a throttle opening and an intake air amount.

FIG. 5 is a flowchart showing a process of atmospheric pressure correction of the control unit.

FIG. 6 is a flowchart showing the processing of an atmospheric pressure prediction routine.

FIG. 7 is a time chart diagram when a vehicle descends a slope.

FIG. 8 is a relationship diagram between an operating state and an atmospheric pressure determination region for explaining the problem of the present invention.

9 is a relationship diagram between a change in ISC control amount and atmospheric pressure determination in the case of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Operating state detection means 2,43 Intake air amount storage means for determination 3 Actual intake air amount detection means 4,44 Atmospheric pressure determination means 5 Idle speed adjustment means 6 Idle speed control means 7,45 Atmospheric pressure fluctuation detection means 8 , 47 Learning prohibiting means 9, 46 Learning value resetting means 21 Engine body 29 Air flow sensor (actual intake air amount detecting means) 42 ISC control means (idle speed control means)

Claims (4)

[Claims] 1. An operating state detecting means for detecting an operating state of an engine, and a set intake air amount for atmospheric pressure determination corresponding to the operating state in an atmospheric pressure determination region preset corresponding to the operating state of the engine. A determination intake air amount storage means for storing and outputting the set intake air amount based on the detected value of the operating state; an actual intake air amount detection means for detecting an actual intake air amount sucked into the engine; Atmospheric pressure determination means for determining atmospheric pressure based on the relationship between the actual intake air amount detected by the intake air amount detection means and the set intake air amount output from the determination intake air amount storage means, and an engine idle The idle rotation speed adjusting means for adjusting the rotation speed is learned and controlled so that the idle rotation speed becomes a target rotation speed, and is based on the atmospheric pressure determined by the atmospheric pressure determining means. In an engine control device including an idle speed control means for correcting the control amount of the idle speed adjusting means, an atmospheric pressure fluctuation detection for detecting a fluctuation state of the atmospheric pressure value judged by the atmospheric pressure judging means. A learning prohibiting means for prohibiting learning by the idle speed control means when the fluctuation state of the atmospheric pressure value detected by the atmospheric pressure fluctuation detecting means is a large fluctuation. A characteristic engine idle speed control device. 2. The method according to claim 1, wherein the atmospheric pressure fluctuation detecting means is based on the deflated value of the atmospheric pressure value judged by the atmospheric pressure deciding means, and the previous value and the present value of the deflated value. The engine idle speed control device according to claim 1, wherein the fluctuation state of the atmospheric pressure is detected based on the magnitude of the deviation from the value. 3. The learning prohibition means according to claim 1,
When the fluctuation state of the atmospheric pressure value detected by the atmospheric pressure fluctuation detecting means is a large fluctuation, a learning value resetting means for resetting the learning value obtained when the fluctuation state of the atmospheric pressure value is a small fluctuation is provided. An idle speed control device for an engine characterized by being provided. 4. The idle speed control means according to claim 3, having a learning value for each of various loads acting on the engine, and the learning value resetting means resets all of the learning values for each load. Idle speed control device for an engine configured as described above.