JPH05263691A - Control device for supplementary air amount to engine - Google Patents

Abstract

PURPOSE:To provide an aux. air amount control device for engine, with which HC exhaust of engine due to lack of the suction air amount can be reduced. CONSTITUTION:A throttle valve 3 is installed in the suction pipe 31 of an engine 1, and aux. air is led from upstream to downstream of the throttle valve through an aux. air passage 5 while detouring the throttle valve 3. The aux. air passage 5 is fitted with an ISC valve 6 to adjust the rate of flow of the aux. air. The map of isotropic air amount curves is stored in a Bu-RAM of an ECU 21. The ECU 21 determines the target suction pressure corresponding to the engine revolving speed from this map and controls the ISC valve 6 by feedback control so that the time differentiated value of the current suction pressure is identical to that of the target suction pressure value. The ECU 21 sets the target suction pressure to the specified value KPfix forcedly when the actual suction pressure approaches the misfire limitation so that this limitation is not exceeded downward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine auxiliary air amount for controlling an amount of auxiliary air supplied to an engine from an auxiliary air passage provided so as to bypass a throttle valve provided in an intake pipe of the engine. The present invention relates to a control device, and more particularly to control of an amount of auxiliary air when the engine changes from a non-idle state to an idle state.

[0002]

2. Description of the Related Art Conventionally, an auxiliary air amount control device for an engine is disclosed in Japanese Patent Application Laid-Open No. 3-258949.
As shown in FIGS. 26 and 27, this is because the delay of the intake system delays the filling of the air amount during deceleration, and the engine intake air amount becomes insufficient, resulting in insufficient torque and reduced rotation. Therefore,
In the above publication, as shown by A in FIG. 27, the amount of air passing through the throttle is compensated so that the engine intake air amount does not fall below the air amount (constant amount) required during stable idle.

In FIG. 28, the engine intake air amount Gou
When t is constant, the engine speed N and the intake pressure P change along the equal air amount line shown in FIG. 29 so that the air amount becomes equal. Considering the case of deceleration from a certain operating state on the equal air amount line (rotation speed-intake pressure curve) in FIG. 29,
The engine intake air amount (indicated by the dotted line in the figure) is lower than the stable idle intake air amount during deceleration. Therefore, the rotation is reduced. On the other hand, in order to control the engine intake air amount during deceleration to be constant (= stable idle intake air amount), follow the equal air amount line required to maintain idle as shown by the solid line in the figure. You can return to idol.

Therefore, as shown in FIG. 30, the intake pressure when the engine intake air amount is constant can be uniquely determined with respect to the rotational speed from the equal air amount line required to maintain idle. That is, if the auxiliary air amount is controlled so that the intake pressure becomes a pressure obtained from the equal air amount line at the time of stable idling, the engine intake air amount can be made the air amount at stable idling, and a decrease in rotation can be prevented.

More specifically, since the equal air quantity line is displaced by the engine load, in the above publication, the intake pressure change amount per unit time is uniquely obtained from the equal air quantity line with respect to the rotational speed. Feedback control was performed by adding an air amount proportional to the difference so as to reach the amount (target value).

[0006]

However, in the above publication, the control for increasing the opening degree of the idle control valve is not executed until the time t1 in FIG. There is a risk of misfire. That is, when the time point of t1 in FIG. 31 is indicated by an equal air amount line, it corresponds to B in FIG. 29, and at a point (B in FIG. 29) that intersects with the intake pressure obtained from the equal air amount line during deceleration, the intake pressure H is already below the misfire limit, H
A large amount of C is discharged.

Therefore, an object of the present invention is to provide an auxiliary air amount control device for an engine which can reduce the emission of HC from the engine due to a shortage of the intake air amount.

[0008]

A first invention, as shown in FIG. 32, is an auxiliary device that bypasses a throttle valve arranged in an intake pipe of an engine and guides auxiliary air from an upstream side of the throttle valve to a downstream side of the throttle valve. An air passage M1, an actuator M2 arranged in the auxiliary air passage M1 for adjusting the flow rate of the auxiliary air, and an intake pressure detecting means M3 for detecting an intake pressure.
And an engine speed detecting means M4 for detecting the engine speed, and a memory storing the relationship between the engine speed and the intake pressure when the engine intake air amount is constant when the non-idle state is shifted to the idle state. The target intake pressure corresponding to the engine speed by the engine speed detecting means M4 is obtained using the means M5 and the data of the storage means M5, and the time differential value of the intake pressure and the intake pressure detecting means M3.
The first control for controlling the actuator M2 by feedback control so that the time differential value of the intake pressure due to
Actuator control means M6 and second actuator control means for controlling the actuator M2 so that the intake pressure does not fall below the misfire limit value when the intake pressure by the intake pressure detection means M3 approaches the misfire limit value of the engine. The gist is an auxiliary air amount control device for an engine provided with M7.

As shown in FIG. 33, a second aspect of the present invention is an auxiliary air passage M11 that bypasses a throttle valve provided in an intake pipe of an engine and guides auxiliary air from an upstream side of the throttle valve to a downstream side of the throttle valve. An actuator M1 arranged in the auxiliary air passage M11 for adjusting the flow rate of the auxiliary air.
2, an intake pressure detecting means M13 for detecting an intake pressure, and an engine speed detecting means M14 for detecting an engine speed.
And, in the intake pressure region larger than the engine misfire limit value, while storing the relationship between the engine speed and the intake pressure when the engine intake air amount at the time of transition from the non-idle state to the idle state is stored, In the intake pressure region smaller than the misfire limit value, a storage means M15 that stores an intake pressure equal to or higher than the misfire limit value with respect to the engine speed, and the engine speed by the engine speed detection means M14 using the data of the storage means M15. The target intake pressure corresponding to the intake pressure is calculated, and the time differential value of the intake pressure and the intake pressure detecting means M1.
The gist is an auxiliary air amount control device for an engine, which is provided with an actuator control means M16 which controls the actuator M12 by feedback control so that the time differential value of the intake pressure by 3 becomes the same.

[0010]

In the first aspect of the invention, the first actuator control means M6 uses the data of the storage means M5 to obtain the target intake pressure corresponding to the engine speed by the engine speed detection means M4, and the time derivative of the intake pressure. Value and intake pressure detection means M3
The actuator M2 is controlled by the feedback control so that the time differential value of the intake pressure due to Eq. Further, the second actuator control means M7 is the intake pressure detection means M3.
When the intake pressure due to ## EQU1 ## approaches the misfire limit value, the actuator M2 is controlled so that the intake pressure does not drop below the misfire limit value. As a result, the intake pressure is prevented from becoming smaller than the misfire limit value.

According to a second aspect of the present invention, the memory means M15 stores the engine speed and intake air when the engine intake air amount is constant when the non-idle state is shifted to the idle state in the intake pressure region larger than the misfire limit value. The relationship with the atmospheric pressure is stored, and in the intake pressure region smaller than the misfire limit value, the intake pressure above the misfire limit value is stored with respect to the engine speed. Then, the actuator control means M16 uses the data of the storage means M15 to detect the engine speed M14.
The target intake pressure corresponding to the engine speed is calculated, and the actuator M12 is controlled by feedback control so that the time differential value of the intake pressure and the time differential value of the intake pressure detected by the intake pressure detecting means M13 match. As a result, the intake pressure is prevented from becoming smaller than the misfire limit value.

[0012]

【Example】

(First Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an overall configuration diagram around an engine mounted on an automobile. In the intake system of the engine 1, a throttle valve 3 is arranged in an intake pipe 31 upstream of the surge tank 2, and an idle switch 4 that is turned on when the throttle valve 3 is fully closed is attached. Further, an auxiliary air passage 5 is provided so as to bypass the throttle valve 3 and provide air from the upstream side of the throttle valve to the surge tank 2 on the downstream side of the throttle valve. In this auxiliary air passage 5, an idle control valve (hereinafter referred to as IS
A C valve) 6 is provided. As the ISC valve 6, a well-known proportional electromagnetic type (linear solenoid) control valve, a vacuum switching valve (VSV), or the like is appropriately used. A temperature sensor 7 for detecting the intake air temperature is attached on the upstream side of the throttle valve 3. Further, a pressure sensor 8 for detecting the intake pressure downstream of the throttle valve 3 is attached to the surge tank 2. The surge tank 2 is connected to the combustion chamber of the engine 1 via an intake manifold 9 and an intake port 10. And
A fuel injection valve 11 is attached to each cylinder so as to project into the intake manifold 9.

The combustion chamber of the engine 1 has an exhaust port 1
2 and an exhaust manifold 13 to connect to a three-way catalyst (not shown). An O ₂ sensor 14 that detects the residual oxygen concentration in the exhaust gas and outputs an air-fuel ratio signal is attached to the exhaust manifold 13. A water temperature sensor 16 is attached to the engine block 15 so as to detect the cooling water temperature of the engine 1 so as to penetrate the engine block 15 and project into the water jacket.

Further, the cylinder head 17 of the engine 1
A spark plug 18 is attached to each cylinder so as to penetrate through the cylinder and project into the combustion chamber. The spark plug 18 is connected via a distributor 19 and an igniter 20 to an electronic control unit (hereinafter referred to as ECU) 21 including a microcomputer and the like. Inside the distributor 19, a cylinder discrimination sensor 22 and a crank angle sensor 23, each of which is composed of a single rotor fixed to a distributor shaft and a pickup fixed to a distributor housing, are attached. In the case of a 6-cylinder engine, the cylinder discrimination sensor 22
Outputs a cylinder discrimination signal every 720 ° C. A, and the crank angle sensor 23 outputs a rotation speed signal every 30 ° A.

As shown in FIG. 2, the ECU 21 includes a central processing unit (CPU) 24, a read only memory (ROM) 25, a random access memory (RAM) 26, a backup RAM (hereinafter,
A Bu-RAM) 27, an input / output port 28, an analog-digital converter (ADC) 29, and a bus 3 such as a data bus or a control bus connecting these.
It is configured to include 0. Then, the input / output port 28
A cylinder discrimination signal, a rotation speed signal, a throttle fully closed signal, and an air-fuel ratio signal are input to the. Also, the input / output port 28
Is an ISC valve control signal for opening and closing the ISC valve 6, a fuel injection signal for opening and closing the fuel injection valve 11,
An ignition signal for turning on / off the igniter 20 is output to a drive circuit (not shown). The drive circuit controls the ISC valve 6, the fuel injection valve 11, and the igniter 20 in accordance with these output signals.

Further, an intake pressure signal, an intake temperature signal, and a water temperature signal are input to the ADC 29. And ADC2
The CPU 9 sequentially converts these signals into digital signals in accordance with instructions from the CPU 24.

Further, the Bu-RAM 27 stores an equal air amount line map for each engine load shown in FIG.
The equal air amount line shows the relationship between the engine speed and the intake pressure when the engine intake air amount is constant when the non-idle state is shifted to the idle state.

In this embodiment, the ISC valve 6 serves as the actuator, the pressure sensor 8 serves as the intake pressure detecting means, the crank angle sensor 23 serves as the engine speed detecting means, and the CP serves as the CP.
At U24, the first and second actuator control means are
The Bu-RAM 27 constitutes a storage means.

Next, the operation of the engine auxiliary air amount control device thus constructed will be described. C in FIGS.
The deceleration control processing which PU24 performs is shown. Further, FIG. 14 shows a time chart for explaining the flowchart. Here, the deceleration control is a routine that replaces the dashpot control during deceleration from when the idle switch 4 is turned on to when the engine speed reaches the target engine speed after the idle switch 4 is turned on. Is repeatedly calculated until is satisfied.

First, in step 100 of FIG. 3, the state of the idle switch 4 is detected. Here, if the idle switch 4 is off, the routine returns without executing the control amount calculation routine after step 102.

When the idle switch 4 is turned on (see FIG.
(Timing of t1 in 4), the process proceeds to step 102. Here, the flag NISCMODE indicating the engine state is
Flag when idle switch is off NISCMODE =
Since it has not been rewritten from 5, the process proceeds to step 103. That is, the control during deceleration is step 100, step 1
In 02, in the routine that is executed after the idle switch 4 is changed from the OFF state to the ON state, the deceleration control is executed every 100 ms until the end condition is satisfied.

Steps 103 to 106 are an initial setting routine. First, in step 103, the engine 1
The predetermined control amount DISCLRN is set in accordance with the load state of, and the routine proceeds to step 104. Specifically, as will be described later, among the learning control amounts GLRN1, GLRN2, and GLRN3 stored in the Bu-RAM 27 according to the load state of the engine 1 (air conditioner operating state, electric load state, etc.), the load state at that time is supported. The learned control amount is the predetermined control amount DIS
It is set as CLRN. In step 104, the predetermined control amount DISCLRN set in step 103 is set as the control amount DISC.

Next, the routine proceeds to step 105, where the parameters required during the deceleration calculation are initialized. For example, Pm
r0 = Pmr, Pt0 = Pt. And step 10
At 6, the idle switch 4 is turned from OFF to ON (in a deceleration state), and the flag NISCMODE is set to "4" because the initialization of the parameters necessary for the deceleration control calculation is completed. That is, NISCMODE = 4 is a flag at the time of control entry during deceleration. Further, the process returns to FIG.

At the next calculation, if the idle switch 4 remains ON, the process proceeds from step 100 to step 102, where N
Since ISCMODE = 4 has been rewritten, the process proceeds from step 107 to step 111 in FIG.

Steps 111 to 118 require the amount of auxiliary air in the control during deceleration, that is, as shown in FIG. 14, (1) the intake pressure Pmr approaches the misfire limit value as a measure for reducing HC during deceleration. (2) The engine intake air flow rate Gout is the air flow rate G required to maintain idle to prevent the engine speed from dropping during deceleration.
Determine if it is less than in. And the intake pressure P
If mr approaches the misfire limit value or Gout falls below Gin, the auxiliary air amount DEC is determined in steps 119 and 121.
Calculate F, DECM.

The processing after step 111 will be described. In step 111, the actual intake pressure Pmr detected by the pressure sensor 8 and the actual intake pressure P acquired in the previous calculation.
Read mr0, and proceed to step 112. Step 1
At 12, it is determined whether the intake pressure Pmr is less than or equal to a predetermined value KPfix. This predetermined value KPfix is a value slightly larger than the misfire limit value. If it is determined that the value is not less than or equal to the predetermined value KPfix, the process proceeds to step 114.
In step 114, the time differential value (change amount per unit time) of the actual intake pressure is obtained as DELPMR = Pmr-Pmr0.

In step 115, the time differential value DE of the intake pressure
It is determined whether LPMR is "0" or more. Here, if the time differential value DELPMR of the intake pressure is "0" or less, the routine proceeds to step 116. In step 116, a flag NISCMODE = 10 indicating the engine state that the intake pressure Pmr has shifted in the negative direction during deceleration is set, and the routine proceeds to step 122. Here, the state of NISCMODE = 10 indicates that the engine intake air amount Gout is larger than the throttle passing air amount Gin. In other words, by the equation of state of gas

[0029]

[Equation 1]

Therefore, Gin <Gout, that is, dP
mr <0. The state of NISCMODE = 10 also indicates that the intake pressure Pmr is not close to the misfire limit value. In this state, the auxiliary air amount DECF,
Neither DECM is needed.

The auxiliary air amounts DECM and DECF are required when the intake pressure Pmr approaches the misfire limit value, or when the engine intake air amount Gout is below the air amount Gin required to maintain idle. It is a point. That is, (1) the point at which the intake pressure Pmr becomes less than or equal to the predetermined value KPfix, or (2) the time differential value DELP of the intake pressure Pmr.
This is the point where MR <0 to DELPMR ≧ 0.

Here, the intake pressure behavior during actual deceleration differs depending on the operating state. That is, in the case shown in FIG. 14, unless the auxiliary air amount DECF is supplied, the intake pressure Pmr becomes equal to or less than the predetermined value KPfix as shown by the broken line. Moreover, FIG.
In the case of 5, the intake pressure does not fall below the predetermined value KPfix even if the auxiliary air amount DECF is not supplied. The behavior in the case of FIG. 14 in the equal air amount map is shown in FIG. 16, and the behavior in the case of FIG. 15 is shown in FIG.

A case where the behavior as shown in FIGS. 14 and 15 is taken on the flowchart will be described. First, the case where the intake pressure Pmr becomes equal to or lower than the predetermined value KPfix after deceleration in FIG. 14 will be described.

As described above, when the time differential value DELPMR <0 of the intake pressure after deceleration, NISCMODE = 1.
Although 0, the engine state in which the amount of auxiliary air is unnecessary is maintained during NISCMODE = 10, so step 12 in FIG.
At 2, DECF = DECM = 0 and the ISC control amount is calculated as follows. In step 123 of FIG. 5, DISCLRN, which is a result of learning the amount of air required to maintain idle according to the load applied to the engine when the engine is idling and stable, is searched according to the load, and step 12
At 4, the ISC control amount DISC = DISCLRN is calculated. Next, at step 125, Pmr, Pt, Ne read this time for the next calculation, and DE of the result calculated this time
CF, DECM, etc. are stored in the RAM 26 as PMR0, Pt0, Ne0. Then, in step 126, it is determined whether or not the deceleration state has ended. If the end condition is not satisfied, the deceleration control is repeated (NISCMO).
DE = 10).

Next, when the intake pressure Pmr becomes equal to or lower than the predetermined value KPfix (timing t2 in FIG. 14), the routine proceeds from step 100 → 102 → 107 → 108 → 111 → 112 to step 113 in FIG. It was judged that the amount of auxiliary air for reduction measures became necessary, and NISC
MODE = 12 is set. And step 119
The auxiliary air amount DECF is calculated at. NISCMOD
While E = 12, the idle switch 4 is turned off or it is determined in step 120 that the DECF operation has ended (see FIG. 1).
The DECF calculation is repeatedly executed at each deceleration-time control calculation timing until the condition (described later using the flowchart of 0) is established, and is reflected in the ISC control amount. That is, DECF
The region where the calculation is executed is a region where the target intake pressure Pt <predetermined value KPfix obtained with respect to the engine speed from the equal air amount line map for each load applied to the engine,
It is indicated by Z2 at 6. When Pt ≧ KPfix is satisfied (timing of t3 in FIG. 14), the ending condition is satisfied in step 120 of FIG. 4, and NISCMODE = 15 is rewritten to shift to the control for returning to the target idle rotation along the equal air amount line.

When NISCMODE = 15 is set,
At the next deceleration control calculation timing, step 1 in FIG.
00 → 102 → 107 → 108 → 109 → 110 → 12
In step 121, the time differential value DELPMR of the intake pressure and the engine speed N from the equal air quantity line are returned to return to the target idle engine speed along the equal air quantity line.
The auxiliary air amount DECM is calculated by PI control according to the deviation DELP (= (Pt-Pt0) -DELPMR) from the intake pressure time differential value (Pt-Pt0) found for e, and IS
It is reflected in the C control amount DISC.

Here, the control amount D in step 123 of FIG.
The ISCLRN selection routine will be described later with reference to the flowchart of FIG. 6, but DISCLRN is used when the engine is stably supplying the air amount necessary to maintain the idle for each load applied to the engine in the vicinity of the target idle (Ne feedback). (During control) is the amount of air learned.

Therefore, in step 124, the ISC control amount D
The ISC is obtained by adding the insufficient air amount DECM to the learning value (DECF = 0). The above calculation is repeatedly executed at each calculation timing during deceleration until the target idle engine speed Ne is reached.
If the end determination is established in step 126 of No. 1, it is determined that the auxiliary air amount reaches an unnecessary engine state, and the flag NIS
Rewrite CMODE from "15" to "7" (Fig. 14
reference). When NISCMODE = 7, steps 100 → 102 → 107 → 108 → 109 → 110 → 1 in FIG.
28, and shifts to the next rotation feedback control (when shifting, DISC = DISCLRN, DECM).
= DECF = 0).

On the other hand, the auxiliary air amount D after deceleration shown in FIG.
Intake pressure is a predetermined value KPfix (misfire limit) without ECF
If the following is not true, that is, N described in FIG.
A case where there is no area where ISCMODE = 12 will be described.

As described above, when the time differential value DELPMR <0 of the intake pressure after deceleration, NISCMODE = 10. During this NISCMODE = 10, the engine is in the state where the auxiliary air amount is unnecessary, so step 12 in FIG.
At 2, DECF = DECM = 0 and the ISC control amount is calculated as follows. In step 123 of FIG. 5, the amount of air required for maintaining the idling according to the load applied to the engine is searched for from the control amount DISCLRN that is a result of learning when the engine is idling and stable, and in step 124, ISC control amount DISC = DISCL
Calculated as RN.

Next, at step 125, the Pmr, Pt, Ne read this time for the next calculation, the DECF, DECM, etc. of the result calculated this time are stored in the RAM 26. Then, in step 126, it is determined whether or not the deceleration state has ended, and if the end condition is not satisfied, the deceleration control is repeated (NISCMODE = 10).

Next, the time derivative of intake pressure DELPMR ≧
When it reaches 0 (timing t2 in FIG. 15), the NIS
Since CMODE = 10, step 100 of FIG.
102 → 107 → 108 → 111 → 112 → 114 → 1
The flow proceeds from 15 → 117 → 118, and in step 118, the NISC MODE is rewritten to “15” assuming that the engine intake air amount falls below the air amount required for maintaining the idle state. If NISCMODE = 15 is set, step 1 is performed at the next deceleration control calculation timing.
00 → 102 → 107 → 108 → 109 → 110 → 12
In step 121, the time differential value DELPMR of the intake pressure and the intake pressure time derivative obtained from the equal air amount line with respect to the engine speed Ne in order to return to the target idle engine speed along the equal air amount line. Deviation from the value (Pt-Pt0) DELP (= (Pt-Pt0) -DELPMR)
The auxiliary air amount DECM is calculated by the PI control according to the above, and is reflected in the ISC control amount DISC in steps 123 and 124.

As will be described later, in this DECM calculation routine, the target intake pressure Pt is searched from the equal air amount map given for each load applied to the engine, and the time differential value DELPMR of the actual intake pressure is the target intake pressure Pt. Deviation DELP (= Pt-Pt0) -DELPM so that it becomes a time differential value
The auxiliary air amount DEC is calculated by PI control according to R).

The above calculation is repeatedly executed at each calculation timing during deceleration until the target idle engine speed is reached, and the end determination is established in step 126. Here, as will be described later with reference to the flowchart in FIG. 11, a state in which the engine rotation speed Ne approaches the target idle engine rotation speed and the change amount | Ne-Ne0 | of the engine rotation speed Ne is equal to or less than a predetermined value is equal to or longer than a predetermined time. Auxiliary air amount D, assuming that the target idle engine speed was reached when continued
ECM = 0, and the state is represented by NISCMODE = 7 (see FIG. 15). Then, when the idle switch is in the ON state at the next calculation, NISCMODE = 7, so steps 100 → 102 → 107 → 108 → 109.
→ 110 → 128 next control (Ne feedback control)
Will be moved to. ISC control amount during transition is DEC
Since F = DECM = 0, DISC = DISCLR
N.

Next, the DISCLRN selection routine of step 103 of FIG. 3 and step 123 of FIG. 5 will be described with reference to FIG. The DISCLRN selection subroutine is a process for reading the result of learning the air amount required to maintain the idle for each load applied to the engine.

First, in steps 200 and 201, the load on the engine is determined. In step 200, it is determined whether the air conditioner and the electric load are turned on. If the engine is not loaded, the process proceeds to step 202 and the learning value GLRN1 (ISC learning value when the engine is not loaded) is set to DISCLRN. On the other hand, if it is determined in step 200 that the engine is under load, step 20
Proceed to 1 to determine whether the air conditioner is on. When the air conditioner is on (or both the air conditioner and the electric load are on), the routine proceeds to step 203, where the learning value GLRN2 is set to DIS.
CLRN. On the other hand, when it is determined in step 201 that the air conditioner is not on, that is, when only the electric load is on, the routine proceeds to step 204, where the learning value GLRN
DISCL of 3 (ISC learning value when only electric load is on)
RN. GLRN1, GLRN2, GLRN3
The learning method will be described later with reference to FIG.

FIG. 9 shows the DECM operation routine in step 121 in FIG. 4, and the PCM in step 400 in FIG.
The t search routine is shown in FIG. The Pt search subroutine will be described. This searches for the target intake pressure Pt with respect to the engine speed from a map of equal air amount given for each engine load.

First, at step 300, the engine speed N
e is read, and the load on the engine is determined in steps 301 and 302. That is, in step 301, it is determined whether both the air conditioner and the electric load are off. If they are off, in step 303 the target intake pressure Pt found for the engine speed Ne is searched from the equal air amount map at the time of no load. .. On the other hand, if both the air conditioner and the electric load are on in step 301 or one of them is on, step 302
Go to and determine if the air conditioner is on.

When the air conditioner is on (only the air conditioner is on or both the air conditioner and the electric load are on), step 303
At, the target intake pressure Pt found for the engine speed Ne is searched from the equal air amount map when the air conditioner is on.

On the other hand, if it is determined in step 302 that the air conditioner is off (only the electric load is on), step 30
At 3, the target intake pressure Pt found for the engine speed Ne is searched from the equal air amount map when only the electric load is on.

Next, the DECF calculation (auxiliary air amount for HC reduction countermeasure during deceleration) routine of step 119 of FIG. 4 is shown in FIG.
Will be explained. The DECF calculation routine uses the engine speed Ne actually taken from the point at which the intake pressure Pmr decreases after deceleration and reaches the predetermined value KPfix so that the intake pressure Pmr does not fall below the misfire limit (below the predetermined value KPfix) during deceleration. On the other hand, according to the deviation (KPfix-Pmr), the intake pressure Pmr reaches a predetermined value KPfix until a point where the target intake pressure Pt ≧ Pmr obtained from the equal air amount curve map (DECF calculation end condition is satisfied). P
By the I control, the auxiliary air amount DECF is repeatedly calculated at every deceleration control calculation timing (100 ms) and reflected in the ISC control amount DISC.

First, at step 450, the actual intake pressure Pmr
And a deviation DPF = KPfix−Pmr from the predetermined intake pressure KPfix is calculated in step 451. And
In step 452, the DECF (= DECF in the previous calculation is
(Stored in 0) and DPF (= stored in DPF0) are read, and the process proceeds to step 453. In step 453, the auxiliary air amount DECF is calculated by PI control according to the deviation DPF. That is, DECF = a.DECF0 + b.D
PF-c · DPF0. However, a, b, and c are constants determined by the proportional gain and the integral constant.

That is, when Gc (s) = Kp (1+ (1 / Kis)) is inverse Laplace transformed, DECF = DECF0 + {(Kp (1 + Ki / dt) d
t / Ki} .DELP-Kp.DELP0 (a = 1, b = {(Kp (1 + Ki / dt) dt
/ Ki}, c = Kp) Next, the DECM operation routine of step 121 of FIG. 4 will be described with reference to FIG.

This process is necessary for the engine intake air amount to maintain the idle in a stable manner during deceleration from when the idle switch 4 is turned off to when it reaches the target idle engine speed. The shortage is calculated as the auxiliary air amount DECM so as not to fall below the air amount. That is, the control is to return to the target idle engine speed Ne along the equal air amount line.

First, in step 400, the target intake pressure Pt is searched for the engine speed Ne from the equal air amount map given for each load applied to the engine. Next, at step 401, the target air pressure Pt0 at the previous calculation and the time differential value DELPMR (= Pmr-Pmr0) of the actual intake pressure are calculated.
In step 402, and the time differential value (Pt−Pt0) of the target intake pressure and the time differential value DELPM of the actual intake pressure are read.
Deviation from R (= Pmr−Pmr0) DELP (= (Pt
-Pt0) -DELPMR) is calculated.

Then, at step 403, the control amount DECM0 and the deviation DELP0 at the time of the previous calculation are read out, and at step 404, the time differential value DELPMR of the actual intake pressure is obtained by the time differential value of the target intake pressure (obtained from the isometric air amount map). Pt-Pt0), the auxiliary air amount DECM (= a.DECM0) is controlled by PI control according to the deviation DELP.
+ B.DELP-c.DELP0) is calculated.

That is, when Gc (s) = Kp (1+ (1 / Kis)) is inverse Laplace transformed, DECM = DECM0 + {(Kp (1 + Ki / dt) d
t / Ki} .DELP-Kp.DELP0 (a = 1, b = {(Kp (1 + Ki / dt) dt
/ Ki}, c = Kp).

Next, the DECF operation end determination routine of step 120 of FIG. 4 will be described with reference to FIG. This DECF calculation end determination routine is performed in a region where the intake pressure Pt <predetermined value KPfix obtained with respect to the engine speed from the equal air amount line map for each engine load, and the actual intake pressure Pmr.
However, DECF was added as an auxiliary air amount by PI control according to the deviation so that it would be KPfix. Therefore,
The end point is a point outside the above range, and when the end condition is satisfied, the control is returned to the target idle speed along the equal air amount line.

First, at step 480, the target intake pressure Pt is searched for the engine speed from the equal air amount map corresponding to the load applied to the engine (described in FIG. 7). Then, in step 481, the target intake pressure Pt and the predetermined value K
Compare with Pfix, and if Pt <KPfix, return as is and the end condition is not satisfied (NISCMODE = 12
(As is) The calculation of the DFCF is repeated at every control calculation timing during deceleration.

On the other hand, if it is determined in step 481 that Pt ≧ KPfix, the process proceeds to step 482, and NISCMOD
E = 15 is set, and at the time of the next calculation, the DECM calculation (control for returning to the target idle engine speed Ne along the equal air amount line) is performed unless the idle switch 4 is off.

Next, the termination judgment routine of step 126 of FIG. 5 will be described with reference to FIG. Since the control during deceleration is control during deceleration, that is, from when the idle switch 4 is turned on to when it reaches the target idle engine speed, the engine speed approaches the target idle engine speed. When the change amount | Ne-Ne0 | of the engine speed Ne remains below the predetermined value for a predetermined time or longer, it is determined that the target idle engine speed is reached, and the deceleration control is ended.

First, at step 500, the engine rotational speed Ne fetched at each calculation during deceleration and the engine rotational speed Ne0 fetched at the previous calculation are read out. And step 5
01, the unit time of the engine speed Ne (100 m
The change amount per s) ΔNe = | Ne−Ne0 | is calculated.

Next, at step 502, it is judged whether or not ΔNe is less than or equal to a predetermined value K1 (the amount of change is small), and if it is greater than the predetermined value K1 (the amount of change is large), the counter COUNT is set at "503". Since the counter COUNT is equal to or less than the predetermined value K2 in step 505, the engine speed of this time is updated in step 509 assuming that the ending condition is not satisfied.

On the other hand, if it is determined in step 502 that ΔNe is less than or equal to the predetermined value K1 (the amount of change is small), the counter COUNT is incremented by "1" in step 504. Then, in step 505, if the counter COUNT is less than or equal to the predetermined value K2, the end condition is not satisfied and step 509
Proceed to. In step 505, the counter COUNT is set to the predetermined value K.
If it is determined that it is 2 or more (the state of ΔNe ≦ K1 continues for a predetermined time or more), it is determined that the engine speed Ne approaches the target idle engine speed, and in step 506, it is determined that the termination condition is satisfied and NISCMODE = 7. ..

Next, at step 507, the learning value DISCLRN of the ISC control amount according to each engine load (the air amount required during stable idle) is read. Then, in step 508, the ISC control amount DISC = DISCLRN
As a result, the control during deceleration ends.

GLRN in steps 202-204 of FIG.
1 to GLRN3 are set to the control next to step 128 of FIG. 3 (during rotation feedback control). The next control process will be described with reference to FIG.

First, steps 700 to 702 are routines for setting the control amount DISC so that the engine speed Ne becomes the target speed NT set according to the engine state such as the water temperature. In step 700, it is detected whether the engine speed Ne is less than the target speed NT. Here, when the engine speed Ne is less than the target speed NT, the routine proceeds to step 701. In step 701, the control amount DIS
C is the control amount DISC set at the previous control timing
A predetermined amount ΔG is added to 0, and the process proceeds to step 703. On the other hand, if the engine speed Ne is equal to or higher than the target speed NT in step 700, the control amount DIS in step 702.
C is the control amount DISC set at the previous control timing
A predetermined amount ΔG is subtracted from 0, and the process proceeds to step 703.

Steps 703 to 707 are routines for detecting the load state of the engine 1. Step 7
At 03, the states of the air conditioner and the electric load are detected. If both the air conditioner and the electric load are off, the process proceeds to step 704. Flag MODE2 in step 704
Is set to "1" and the process proceeds to step 708. Here, the flag MODE2 indicates the load state of the engine 1. When at least one of the air conditioner and the electric load is turned on in step 703, the process proceeds to step 705, and when the air conditioner is turned on in step 705, the process proceeds to step 706. In step 706, the flag MODE2 is set to "2", and the process proceeds to step 708. On the other hand, if the air conditioner is turned off in step 705, that is, only the electric load is applied to the engine 1, the process proceeds to step 707. Step 707
To set the flag MODE2 to "3", and step 708
Go to.

Step 708 is a routine for setting the learning control amounts GLRN1, GLRN2 and GLRN3 according to the load state. This process will be described with reference to FIG. First, at step 800, it is detected whether or not the content of the flag MODE2 is equal to the content of the flag MODE21 at the previous control timing. Here, the contents of the flag MODE2 and the flag MODE2 at the previous control timing
If the contents of 1 are different, the process proceeds to step 801. In step 801, the counter C1 is reset (C1 = 0),
Go to step 802. Here, the counter C1 is for measuring the duration of time after the current load state is reached. In step 802, the counter C2 is reset (C
2 = 0), and this control ends. Here, the counter C2
Is for measuring the duration of the current controlled variable DISC.

On the other hand, in step 800, the flag MODE2 is set.
Content and flag MODE in the previous control timing
If the contents of 21 are the same, the process proceeds to step 803. In step 803, the counter C1 is incremented by "1", and the process proceeds to step 804. In step 804, it is detected whether or not the value of the counter C1 is equal to or greater than a predetermined value K1, that is, whether or not a predetermined time or more has elapsed since the current load state was reached.
Here, if the value of the counter C1 is less than the predetermined value K1, this processing ends. When the value of the counter C1 is the predetermined value K1 in step 804, the process proceeds to step 805. In step 805, it is detected whether the control amount DISC is equal to the control amount DISC0 at the previous control timing. If the control amount DISC and the control amount DISC0 at the previous control timing are different, the process proceeds to step 806. In step 806, the counter C2 is reset (C2 =
0) and proceed to step 808. On the other hand, step 805
If the control amount DISC is equal to the control amount DISC0 at the previous control timing, the process proceeds to step 807. In step 807, the counter C2 is incremented by "1", and the process proceeds to step 808.

In step 808, it is detected whether or not the value of the counter C2 is equal to or larger than a predetermined value K2, that is, whether or not a predetermined time or more has passed since the current control amount DISC was reached. here,
If the value of the counter C2 is less than the predetermined value K2, this process ends. If the value of the counter C2 is greater than or equal to the predetermined value K2 in step 808, the process proceeds to step 809.

Steps 809 to 813 are a learning control amount update routine. Flag M in step 809
It is detected whether ODE2 is "1". Here, flag M
If ODE2 is “1”, the process proceeds to step 810.
In step 810, the learning control amount GLRN1 corresponding to the load state in which neither the air conditioner nor the electric load is input is updated to the current control amount DISC, and this processing ends. or,
If the flag MODE2 is not “1” in step 809, the process proceeds to step 811. Flag MO in step 811
It is detected whether DE2 is "2". Here, flag MO
If DE2 is “2”, the process proceeds to step 812. In step 812, the learning control amount GLRN2 corresponding to the load state in which the air conditioner is input is updated to the current control amount DISC, and this processing ends. If the flag MODE2 is not "2" in step 811, that is, the flag MODE
If 2 is “3”, the process proceeds to step 813. In step 813, the learning control amount GLRN3 corresponding to the load state in which only the electric load is input is updated to the current control amount DISC, and this processing ends.

As described above, in this embodiment, the CPU 24 (first and second actuator control means) uses the equal air amount line map to set the target intake pressure Pt corresponding to the engine speed.
Is calculated, and the ISC valve 6 (actuator) is controlled by feedback control so that the time differential value (Pt−Pt0) of the intake pressure and the time differential value DELPMR of the actual intake pressure match. The atmospheric pressure Pmr is a predetermined value K
When the pressure falls below Pfix and approaches the misfire limit value, the target intake pressure is forcibly set to a predetermined value KPfix so that the intake pressure does not fall below the misfire limit value. As a result, it is possible to prevent the intake pressure from becoming lower than the misfire limit value, and it is possible to reduce the emission of HC from the engine due to the shortage of the intake air amount.

That is, in the device disclosed in Japanese Patent Laid-Open No. 3-258949, the engine fetched for each calculation from the equal air amount line map (air amount line necessary for maintaining idle) of the intake pressure behavior during deceleration shown in FIG. This is a control for returning to the target idle speed along the equal air amount line from a point where the intake pressure Pt obtained with respect to the rotation speed Ne crosses (matches), and thereby prevents the engine speed from dropping immediately after deceleration. , It can quickly converge to the target engine speed. That is, the control was to supply the minimum amount of auxiliary air so that the engine speed would not drop. However, at the point where the intake pressure intersects with the intake pressure obtained from the equal air amount line during deceleration (B in FIG. 29), a large amount of HC is discharged if the intake pressure is already below the misfire limit. On the other hand, in the present embodiment, the intake pressure of the equal air amount map and the value KPfix which is slightly larger than the misfire limit value are used to return to the target idle along the larger one. That is, when the actual intake pressure becomes equal to or lower than the predetermined value KPfix, the auxiliary intake air amount is supplied so that the actual intake pressure becomes the predetermined value KPfix, and thereafter, when the intake pressure intersects with the intake pressure obtained from the equal air amount line, the equal air amount is obtained. HC is reduced by returning to the target idle speed along the line. (Second Embodiment) Next, the second embodiment will be described focusing on the differences from the first embodiment.

In this embodiment, the characteristic line shown by the solid line in FIG. 24 is used as the equal air amount line map for each load stored in the Bu-RAM 27. That is, in the intake pressure region (the region of the first predetermined value or more) slightly larger than the misfire limit value, the engine speed and the intake pressure when the engine intake air amount when the non-idle state is changed to the idle state are constant. In addition to storing the relationship with, the misfire limit value Xlim with respect to the engine speed in the intake pressure region smaller than the first set value.
The above intake pressure is stored.

The processing executed by the CPU 24 will be described below with reference to FIGS. 19 to 21 correspond to FIGS. 3 to 5 in the first embodiment. Figure 1
In step 9, after determining in step 100 whether or not the idle switch 4 is on, in step 102, the flag NIS is set.
It is determined whether CMODE = 5, and initially NISCMODE =
Since it is 5, the process proceeds to step 103. The DISLRN selection process is performed in step 103, and the DISCLRN selected in step 104 is set as the control amount DISC.
At 5, Pt and Pmr are initialized. And step 10
After setting the flag NISCMODE = 4 in 6 and returning in FIG.

In the next calculation, step 1 in FIG.
00 → 102 → 107 → Go to step 110 in FIG. In steps 110 to 116, it is determined whether the auxiliary air amount is required in the deceleration control, that is, whether the engine intake air is lower than the air amount required to maintain the idling, and if it is lower, in step 120. The auxiliary air amount DEC is calculated.

The steps after step 110 will be described. In step 110, the actual intake pressure Pmr is read, and in step 1
At 11, the target intake pressure Pt is set. And step 1
In step 12, the actual intake pressure Pmr is compared with the target intake pressure Pt retrieved from the equal air amount line map for the actual engine speed. If the actual intake pressure Pmr> Pt, the routine proceeds to step 113. In step 113, the time differential value DELPMR of the intake pressure
Is calculated as Pmr−Pmr0. However, Pmr0 is the previous value of Pmr. Further, in step 114, it is judged whether the time differential value DELPMR of the intake pressure is "0" or more, and D
If ELPMR <0, the flag NISC is determined in step 115.
Set MODE = 10 and proceed to step 117.

Here, the state of the flag NISCMODE = 10 indicates that the engine intake air amount is larger than the throttle passing air amount, and the engine intake air amount remains idle as described in the first embodiment. It is determined that the amount of air required is not less than that required, and the auxiliary air amount DEC is not required in this state.

The auxiliary air amount DEC is required at the point where the engine intake air amount Gout is below the air amount required to maintain idle, so during deceleration, the actual intake pressure Pmr is equal to the equal air amount line. Matches the target intake pressure Pt obtained from the map with respect to the engine speed (Ne, Pmr during deceleration)
This is the point where the behavior intersects with the equal air volume line. At this time, when Gin <Gout to Gin ≧ Gout, that is,
It is when DELPMR <0 to DELPMR ≧ 0. Therefore, the DEC calculation start point is (1) the point where Pmr matches Pt, or (2) DELPMR <
0 to DELPMR ≧ 0.

Here, in the present embodiment, the equal air amount line necessary for stably maintaining the idle engine speed indicated by the broken line in FIG. 25 is set to the first line so that the intake pressure does not become lower than the misfire limit value. In order to prevent the predetermined value of 1 from falling below the second predetermined value, it is raised as shown by the solid line in the figure. This second predetermined value is the misfire limit value Xlim. Therefore, the point where Pmr matches Pt is DELPMR <
When it is satisfied from 0 to more than DELPMR ≧ 0 (behavior shown in the figure), it crosses in the raised region shown by “A” in FIG. 25, and the target idle along the raised equal air amount line. Return to engine speed. Therefore, the intake pressure does not fall below the misfire limit.

Further, DELPMR <0 to DELPMR ≧
When 0 is satisfied earlier than the point where Pmr matches Pt (behavior shown in FIG. 25), the idle state is maintained due to the change with time of the engine in the non-raised region shown by “B” in FIG. Therefore, the map moves upward from the air amount line of the map having the air amount line required for the above.

These will be described with reference to flowcharts. If (1) is satisfied early, the time differential value DELPMR <0 of the intake pressure after deceleration is satisfied as described above, and therefore the flag NISCMOD is determined in step 115 of FIG.
E = 10 is set, and in step 117 DEC = 0,
At steps 121 and 122 in FIG. 21, the ISC control amount DI
If SC = DISCLRN and the ending condition is not satisfied in step 124, the process returns.

Thereafter, the actual intake pressure Pmr becomes the target intake pressure Pt obtained from the equal air amount line, and steps 100 → 102.
→ 107 → 108 → 110 → 111 → 112, and the process proceeds from step 112 to step 118. Step 11
In step 8, the flag NISCMODE is set to "15" because the engine state requiring the auxiliary air amount DEC is set.

Next, when the above (2) is established earlier than (1), the time differential value DELPMR <0 of the intake pressure after deceleration.
Therefore, in step 115, NISCMODE = 1
If it is set to 0 and then DELPMR ≧ 0, steps 100 → 102 → 107 → 108 → 110.
→ 111 → 112 → 113 → 114 → 116, N
Since ISCMODE = 10, the process proceeds to step 118. In step 118, the flag NISCMODE is set to "15" because the engine state requiring the auxiliary air amount DEC is set.

Once NISCMODE = 15 is set, DEC is calculated every unit time unless the idle switch 4 is turned off in step 100 or the end determination is not satisfied in step 124 of FIG.

During the DEC operation, NISCMODE
= 15, step 100 → 102 → 107 →
The process proceeds from 108 to 109 to 119, and in step 119, the time differential value DELPMR of the actual intake pressure is calculated. afterwards,
At step 120, DEC is calculated by the DEC calculation routine. This DEC calculation routine will be described later.

Next, in step 121 of FIG. 21, DISC is performed.
Select LRN and DISCL the DEC in step 122
RN is added to calculate the controlled variable DISC, and step 12
In step 3, the parameters used in the next calculation are stored in the RAM. After that, the end determination is made in step 124.

Here, step 103 of FIG. 19 and FIG.
The DISCLRN selection subroutine of step 121 of 1 is the same as that of FIG. 6 in the first embodiment, and the description thereof will be omitted.

Next, the Pt search subroutine in step 111 of FIG. 20 will be described with reference to FIG. First, in step 300, the engine speed Ne is read, and in steps 301 and 302, the load on the engine is determined.
That is, in step 301, it is determined whether both the air conditioner and the electric load are off. If they are off, in step 303 the target intake pressure Pt found for the engine speed Ne is searched from the equal air amount map at the time of no load. .. On the other hand, step 301
If both the air conditioner and the electric load are on, or one of them is on, the routine proceeds to step 302, where it is determined whether the air conditioner is on.

When the air conditioner is on (only the air conditioner is on or both the air conditioner and the electric load are on), step 303
At, the target intake pressure Pt found for the engine speed Ne is searched from the equal air amount map when the air conditioner is on.

On the other hand, if it is determined in step 302 that the air conditioner is off (only the electric load is on), step 30
At 3, the target intake pressure Pt found for the engine speed Ne is searched from the equal air amount map when only the electric load is on.

Next, the DEC in step 120 of FIG.
The calculation routine will be described with reference to FIG. First, in step 400, the target intake pressure Pt is searched for the engine speed Ne from the equal air amount map given for each load applied to the engine. Next, at step 401, the target intake pressure Pt0 at the time of the previous calculation and the DELPMR calculated at step 119 of FIG. 20 are read. And step 402
Then, the time differential value of the target intake pressure (Pt-Pt0) and the time differential value of the actual intake pressure DELPMR (= Pmr-Pmr0)
Deviation from DELP (= (Pt−Pt0) −DELPM
R) is calculated. In step 403, DEC (= DEC0) at the time of the previous calculation and DELP (= DE at the time of the previous calculation)
Read LP0).

Then, in step 404, PI control is performed according to the deviation DELP so that the time differential value DELPMR of the actual intake pressure becomes the time differential value (Pt-Pt0) of the target intake pressure obtained from the equal air amount line map. Auxiliary air volume DEC (= a ・ DEC0 + b ・ DELP-c ・ DELP
0) is calculated.

That is, when Gc (s) = Kp (1+ (1 / Kis)) is inverse Laplace transformed, DEC = DEC0 + {(Kp (1 + Ki / dt) dt /
Ki} · DELP−Kp · DELP0 (a = 1, b = {(Kp (1 + Ki / dt) dt
/ Ki}, c = Kp).

Here, the termination judgment subroutine of step 124 of FIG. 21 is the same as that of FIG. 11 in the first embodiment, and its explanation is omitted. Also, step 12 in FIG.
The next control subroutine of No. 5 is shown in FIG. 12 in the first embodiment.
The description is omitted here.

As described above, in this embodiment, the Bu-RAM 2
7 (storage means), as shown in FIG. 24, in the intake pressure region larger than the misfire limit value, the engine speed and the intake pressure when the engine intake air amount is constant at the time of shifting from the non-idle state to the idle state. In addition to storing the relationship with, the intake pressure above the misfire limit value was memorized with respect to the engine speed in the intake pressure region smaller than the misfire limit value. That is, in the equal air amount line, the target air pressure Pt is transformed from the first set value to the second set value (misfire limit value Xlim) or less so as not to fall below the misfire limit. Therefore, the deceleration control is control to return to the target idle engine speed along the equal air amount line, so that the actual intake pressure Pmr does not fall below the misfire limit during deceleration and HC can be reduced.

[0098]

As described in detail above, according to the present invention,
It has an excellent effect of reducing the emission of HC from the engine due to the shortage of the intake air amount.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an engine auxiliary air amount control device according to an embodiment.

FIG. 2 is an electrical configuration diagram of an engine auxiliary air amount control device according to an embodiment.

FIG. 3 is a flowchart for explaining the operation.

FIG. 4 is a flowchart for explaining the operation.

FIG. 5 is a flowchart for explaining the operation.

FIG. 6 is a flowchart for explaining the operation.

FIG. 7 is a flowchart for explaining the operation.

FIG. 8 is a flowchart for explaining the operation.

FIG. 9 is a flowchart for explaining the operation.

FIG. 10 is a flowchart for explaining the operation.

FIG. 11 is a flowchart for explaining the operation.

FIG. 12 is a flowchart for explaining the operation.

FIG. 13 is a flowchart for explaining the operation.

FIG. 14 is a time chart for explaining the operation.

FIG. 15 is a time chart for explaining the operation.

FIG. 16 is a diagram for explaining the operation.

FIG. 17 is a diagram for explaining the operation.

FIG. 18 is a diagram showing an equal air amount line map.

FIG. 19 is a flowchart for explaining the operation.

FIG. 20 is a flowchart for explaining the operation.

FIG. 21 is a flowchart for explaining the operation.

FIG. 22 is a flowchart for explaining the operation.

FIG. 23 is a flowchart for explaining the operation.

FIG. 24 is a diagram showing a constant intake air amount line map according to the embodiment.

FIG. 25 is a diagram for explaining an example.

FIG. 26 is a schematic diagram of an intake system for explaining a conventional technique.

FIG. 27 is a time chart for explaining a conventional technique.

FIG. 28 is a schematic diagram of an intake system for explaining a conventional technique.

FIG. 29 is a diagram for explaining a conventional technique.

FIG. 30 is a time chart for explaining a conventional technique.

FIG. 31 is a time chart for explaining a conventional technique.

FIG. 32 is a claim correspondence diagram.

FIG. 33 is a diagram corresponding to a complaint.

[Explanation of symbols]

1 Engine 3 Throttle Valve 5 Auxiliary Air Passage 6 ISC Valve as Actuator 8 Pressure Sensor as Intake Pressure Detection Means 23 Crank Angle Sensor as Engine Rotation Speed Detection Means 24 CPU as First and Second Actuator Control Means Bu-RAM 31 intake pipe as means

Claims (2)

[Claims] 1. An auxiliary air passage that bypasses a throttle valve provided in an intake pipe of an engine and guides auxiliary air from an upstream side of the throttle valve to a downstream side of the throttle valve, and an auxiliary air passage that is provided in the auxiliary air passage. An actuator that adjusts the flow rate, an intake pressure detection unit that detects the intake pressure, an engine speed detection unit that detects the engine speed, and an engine intake air amount when shifting from the non-idle state to the idle state The storage means that stores the relationship between the engine speed and the intake pressure at that time, and the target intake pressure corresponding to the engine speed by the engine speed detection means is obtained using the data of the storage means, and the time of the intake pressure is calculated. A first control for controlling the actuator by feedback control so that the differential value and the time differential value of the intake pressure detected by the intake pressure detecting means match. And a second actuator control means for controlling the actuator so that the intake pressure does not fall below the misfire limit value when the intake pressure detected by the intake pressure detection means approaches the engine misfire limit value. An auxiliary air amount control device for an engine characterized by the above. 2. An auxiliary air passage for guiding auxiliary air from an upstream side of the throttle valve to a downstream side of the throttle valve by bypassing a throttle valve arranged in an intake pipe of an engine; An actuator for adjusting the flow rate, an intake pressure detecting means for detecting the intake pressure, an engine speed detecting means for detecting the engine speed, and a non-idle state to an idle state in an intake pressure range larger than the engine misfire limit value. The relationship between the engine speed and the intake pressure when the engine intake air amount is constant at the time of shifting to is stored, and in the intake pressure region smaller than the misfire limit value, the intake speed above the misfire limit value is exceeded with respect to the engine speed. A storage unit that stores the atmospheric pressure, and a target intake pressure corresponding to the engine speed detected by the engine speed detection unit using the data stored in the storage unit. An engine comprising: an actuator control unit that controls the actuator by feedback control so that the time differential value of the intake pressure and the time differential value of the intake pressure detected by the intake pressure detection unit match. Auxiliary air volume control device.