JP2000320377A - Throttle controller for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent detection errors in a flow meter by correcting a target throttle opening to that within a dead opening area and on the outside of an error opening area associated with the measurement error of the flow meter, when the target throttle opening is within the dead opening area in which the change of an actual throttle opening has no influence on the intake air amount. SOLUTION: In compliance with the number of engine revolutions and opening/closing timing of an intake/exhaust valve, a dead throttle opening APMWOT, a drift suppressing throttle opening TAimin, and a pulsation suppressing throttle opening TAimax are found. A sensitive area 44, a dead area 45, a drift measurement error area 46 and a pulsation measurement error area 47 are determined. In setting of a target throttle opening TAtg inside the dead area 45, it is set on the outside the drift measurement error area 46 and the pulsation measurement error area 47. In this way, measurement errors in an air flow meter due to pressure pulsation/drift inside an intake pipe can be prevented with hardly change of the air intake amount, so that control based on the intake air amount measured by the air flow meter can be carried out precisely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a throttle control device for an internal combustion engine.

[0002]

2. Description of the Related Art This type of throttle control device electronically controls a throttle valve so as to obtain a desired output torque in accordance with an operation state of an internal combustion engine, and is based on an accelerator opening, an engine speed, and the like. The target opening of the throttle valve is obtained, and the throttle valve is opened and closed by an actuator so that the opening of the throttle valve becomes the target opening, thereby adjusting the intake air amount (Japanese Patent Laid-Open No. Hei 5-133257). See).

[0003]

As described in the above-mentioned publication, a flow meter for measuring the amount of intake air is disposed upstream of the throttle valve in the air intake path. The intake air amount detected by the meter is used for controlling the internal combustion engine.

[0004] However, when a high load is applied to the internal combustion engine, the target throttle opening is set near full opening to obtain a high torque, and the throttle opening is almost fully opened. The pulsation of the pressure in the path and the drift in the intake pipe spread to the flow meter, thereby causing a detection error in the flow meter and deteriorating the control accuracy of the internal combustion engine.

The present invention has been made in view of the above-mentioned conventional problems, and provides a throttle control device for an internal combustion engine capable of preventing a detection error of a flow meter arranged upstream of a throttle valve. It is in.

[0006]

In order to solve the above problems, the present invention relates to an internal combustion engine in which a flow meter is provided upstream of a throttle valve and is controlled based on an intake air amount measured by the flow meter. A throttle control device for an internal combustion engine that sets a target opening of the throttle valve based on an engine operating state and controls the throttle valve so that the actual throttle opening becomes the target throttle opening. When the target throttle opening is within a dead opening region where a change in throttle opening does not substantially affect the intake air amount, the target throttle opening is set within the dead opening region and the flow rate is reduced. An opening correction means is provided for correcting an outside of an error opening range relating to a measurement error of the meter.

According to the present invention, when the target throttle opening is within the dead opening region where the change in the actual throttle opening does not substantially affect the intake air amount, the target throttle opening is insensitive. The correction is performed within the opening range and outside the error opening range that causes a measurement error of the flow meter. That is, as long as the actual throttle opening changes within the dead opening region, the intake air amount does not substantially change. Therefore, when the target throttle opening is in the dead opening region, the target throttle opening is set to the flow meter. The measurement error of the flow meter is corrected outside the error opening range, thereby preventing the measurement error of the flow meter without substantially changing the intake air amount.

In one embodiment, the dead opening region is a region having a predetermined opening or more, and the opening correction means corrects the target throttle opening to the predetermined opening.

In this case, the target throttle opening is corrected to a predetermined opening at the boundary of the dead opening region.
The target throttle opening is not unnecessarily adjusted in the dead opening region.

In one embodiment, the error opening area is an area that causes a measurement error of the flow meter, and the opening correction means sets the target throttle opening to the flow rate outside the error opening area. The opening is corrected so that the measurement error of the meter becomes small.

[0011]

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

FIG. 1 is a schematic configuration diagram showing one embodiment of a throttle control device of the present invention. In FIG. 1, an internal combustion engine (hereinafter referred to as an engine) 1 has a throttle valve 4
Is provided. This throttle valve 4 is provided with a throttle actuator 5 as an electronic control actuator.
Adjusts the opening degree, thereby adjusting the amount of air taken into the engine 1.

A piston 9 which reciprocates in a vertical direction in FIG. 1 is provided in a cylinder 8 constituting a cylinder of the engine 1, and the piston 9 is connected to a crankshaft 11 via a connecting rod 10. Above the piston 9, a combustion chamber 13 defined by the cylinder 8 and the cylinder head 12 is formed. The combustion chamber 13 communicates with the intake pipe 2 and the exhaust pipe 3 via the intake valve 14 and the exhaust valve 15.

An intake port 17 of the engine 1 is provided with an electromagnetically driven injector 18. Fuel (gasoline) is supplied to the injector 18 from a fuel tank (not shown). In this case, the air supplied from the upstream of the intake pipe 2 and the injected fuel supplied by the injector 18 are mixed at the intake port 17, and the air-fuel mixture is mixed in the combustion chamber 13 (cylinder) with the opening operation of the intake valve 14. 8). The air-fuel mixture that has flowed into the combustion chamber 13 is compressed therein, and is ignited by an ignition spark emitted from a spark plug 19 to explode. Engine 1
Will get rotational torque by this explosion. The gas after combustion is discharged to the exhaust pipe 3 via the exhaust valve 15 as exhaust gas.

Further, the cylinder 8 (water jacket)
Is provided with a water temperature sensor 21 for detecting the engine water temperature. Further, the crankshaft 11 outputs a pulse signal at every 720 ° CA (crank angle) according to the rotation state, and outputs a pulse signal at every constant crank angle (for example, 30 ° CA). A rotation speed sensor 23 is provided.

Further, an air flow meter 24 for detecting an intake air amount is disposed upstream of the intake pipe 2. The air flow meter 24 is, for example, a hot wire type (hot wire type). The accelerator pedal 25 that is depressed by the driver is the same as the accelerator pedal 25.
An accelerator sensor 26 for detecting the amount of depression of the vehicle is provided. A transmission (not shown) is provided with a shift sensor 28 for detecting a shift position of the transmission.

The cylinder head 12 is provided with a variable valve timing mechanism 27. The variable valve timing mechanism 27 adjusts the opening / closing timing of the intake valve 14 and the opening / closing timing of the exhaust valve 15 in response to the control of the ECU 30.

On the other hand, the ECU 30 has a well-known CPU, RO
It is mainly configured by a microcomputer including an M, a RAM, an I / O circuit, and the like. The ECU 30 includes a water temperature sensor 21, a reference position sensor 22, a rotation speed sensor 2,
3. Input detection signals from the air flow meter 24, the accelerator sensor 26, and the shift sensor 28, and detect the engine water temperature, crank angle, engine speed, intake air amount, accelerator opening, and shift position based on these various detection signals. I do.

The ECU 30 calculates a fuel injection amount (or fuel injection time), an ignition timing, a target throttle opening, a valve timing, and the like based on various detection outputs from the sensor group. ,
The ignition of the ignition plug 19, the opening of the throttle valve 4 by the throttle actuator 5, and the opening and closing timing of the intake and exhaust valves by the variable valve timing mechanism 27 are controlled.

If the throttle valve 4 is almost fully opened when a high load is applied to the engine 1 as in the prior art, the pulsation of the pressure in the intake pipe 2 and the drift in the intake pipe 2 cause Upstream air flow meter 2
4, the detection error occurs in the air flow meter 24. Therefore, in the present embodiment, a state in which pulsation or drift of the pressure in the intake pipe 2 occurs is predicted, and opening and closing control of the throttle valve 4 is performed while avoiding such a state.

FIG. 2 is a flowchart for controlling the opening and closing of the throttle valve 4 while avoiding a state in which pressure pulsation or drift in the intake pipe 2 occurs. According to this flowchart, the opening / closing control of the throttle valve 4 of the present embodiment will be described below.

First, the ECU 30 controls the accelerator sensor 26
And using a shift sensor 28 accelerator opening PDLA and the shift position shift or the like detected by the provisional target throttle opening based on a function f ₁ previously set t-TA
tg is obtained (step 101).

Next, the ECU 30 uses the engine speed NE detected by the speed sensor 23 and the opening / closing timing Vt of the intake / exhaust valve set by the variable valve timing mechanism 27 to set a predetermined function f.
_The dead throttle opening TA _PMWOT is _obtained based on ₂ . Also,
The ECU 30 uses the engine speed NE and the opening / closing timing Vt of the intake / exhaust valve to set a predetermined function f _3.
Based on the above, the drift suppression throttle opening TA _imin is obtained. Furthermore, ECU 30 uses the open-close timing Vt of the engine rotational speed NE and the intake and exhaust valves, determining the pulsation suppression throttle opening TA _imax based on a function f ₄ that is set in advance (step 102).

The calculation in step 102 is performed by, for example, EC
This is performed by referring to data in a data table 31 as shown in FIG. 3 stored in advance in the ROM of U30. That is, the ECU 30 reads a base value corresponding to the engine speed NE and the opening / closing timing Vt of the intake / exhaust valve from the data table 31, and reads this base value into each function f ₂ ,
f _3, and subjected to the correction coefficient in f _4, after correcting the respective correction coefficients, each of said function f _2, f _3, f ₄ in basis insensitive throttle opening TA _Pmwot, nonuniform flow suppression throttle opening T
A _imin and the pulsation suppression throttle opening TA _imax are obtained.

Here, the dead throttle opening TA _PMWOT ,
The drift suppression throttle opening TA _imin and the pulsation suppression throttle opening TA _imax will be described in further detail.

FIG. 4 is a graph showing a variable valve timing machine.
Arbitrary opening / closing timing Vt is set by the structure 27
Throttle opening with respect to engine speed NE
TA _PMWOTCharacteristic curve 41, drift prevention throttle opening T
A_iminCharacteristic curve 42 and the pulsation suppression throttle opening T
A_imaxThe characteristic curve 43 of FIG.

In the graph of FIG. 4, a characteristic curve 41 of the dead throttle opening TA _{PMWOT is} a curve _dividing a sensitive region 44 in which the intake air amount changes with respect to the throttle opening and a dead region 45 in which the intake air amount does not substantially change. Yes, characteristic curve 41
If the above throttle opening is set, that is, the dead zone 4
When the throttle opening is set at 5, the intake air amount does not substantially change with a change in the throttle opening. In addition, the characteristic curve 42 of the drift suppression throttle opening TA _imin
Is a curve that divides the drift measurement error region 46. If the throttle opening is set in the drift measurement error region 46 that is less than the characteristic curve 42, a drift in the intake pipe 2 causes a measurement error in the air flow meter 24. Further, the characteristic curve 43 of the pulsation suppression throttle opening TA _imax is a curve dividing the pulsation measurement error region 47. When the throttle opening is set in the pulsation measurement error region 47 exceeding the characteristic curve 43, the characteristic curve 43 in the intake pipe 2 The measurement error occurs in the air flow meter 24 due to the pulsation of the pressure.

For example, while the constant engine speed NE ₁ shown in the graph of FIG.
When A is gradually increased, the actual intake air amount becomes as shown in FIG.
It changes as shown by the characteristic curve 51 of the graph of FIG. As is clear from the characteristic curve 51, when the throttle opening TA exceeds the dead throttle opening TA _PMWOT , the actual intake air amount hardly changes in response to a change in the throttle opening TA, and the actual intake air amount becomes _smaller. Almost saturated. The characteristic curve 52 indicates the amount of intake air detected by the air flow meter 24. Throttle opening TA is insensitive Throttle opening TA _{PMWO T} or more _Drift suppression throttle opening TA
_{When entering} the range less than _imin (drift measurement error area 46),
And the throttle opening TA is the pulsation suppressing throttle opening TA
When the air flow meter 24 enters a range exceeding the _imax (pulsation measurement error area 47), a measurement error occurs, and the characteristic curve 52 deviates from the characteristic curve 51.

FIG. 5B is a graph showing the target throttle opening TAtg with respect to the provisional target throttle opening t-TAtg.
It shows the characteristic of. As is clear from this graph, when the provisional target throttle opening t-TAtg falls within the range (the drift measurement error region 46) which is _{equal to} or more than the dead throttle opening TA _{PMWOT and} less than the drift suppression throttle opening TA _imin , the target throttle opening TAtg. The drift suppression throttle opening TA
_When the provisional target throttle opening t-TAtg falls within the range (pulsation measurement error area 47) exceeding the pulsation suppression throttle opening TA _imax , the target throttle opening T
Atg is set to the pulsation suppression throttle opening TA _imax . Since both the drift suppression throttle opening TA _imin and the pulsation suppression throttle opening TA _imax enter the dead zone 45, the target throttle opening TAtg is set within the dead zone 45.

Further, the provisional target throttle opening t-TAtg
Enters the sensitive region 44 or the provisional target throttle opening t
When -TAtg enters the dead zone 45 and deviates from the drift measurement error region 46 and the pulsation measurement error region 47, the provisional target throttle opening t-TAtg is set to the target throttle opening TAtg.

In step 102, the dead throttle opening TA _PMWOT , the drift suppression throttle opening shown in the graphs of FIGS. 5A and 5B according to the engine speed NE and the opening / closing timing Vt of the intake and exhaust valves. TA _imin ,
And the pulsation suppression throttle opening TA _imax .

When the opening / closing timing Vt of the intake / exhaust valve is changed, the contents of the graph of FIG. 4 change. Further, when the opening / closing timing Vt of the intake / exhaust valve is kept constant and the engine speed NE is changed, the contents of the graphs in FIGS. 5A and 5B change.

Further, based on not only the engine speed NE and the opening / closing timing Vt of the intake / exhaust valves, but also the amount of exhaust gas recirculated by EGR, etc., the dead throttle opening T
_Pmwot, may be nonuniform flow suppression throttle opening TA _imin, and pulsation suppression throttle opening TA _imax calculated.

Now, the dead throttle opening TA
_{When PMWOT} , the drift prevention throttle opening TA _{i min} , and the pulsation suppression throttle opening TA _imax are obtained, the ECU 30 _calculates
It is determined whether the tentative target throttle opening t-TAtg is _{equal to} or greater than the dead throttle opening TA _PMWOT , that is, whether the tentative target throttle opening t-TAtg falls within the dead zone 45 (step 103). As described with reference to the graph of FIG. 5B, if the provisional target throttle opening t-TAtg does not enter the dead zone 45, that is, if it enters the sensitive region 44 (Step 103, No), the ECU 30 determines The target throttle opening TAtg is set to the temporary target throttle opening t-TAtg.
(Step 104), and by controlling the drive of the throttle actuator 5, the throttle valve 4
Is adjusted to the target throttle opening TAtg.

In this case, since the target throttle opening TAtg enters the sensitive region 44, the amount of intake air also changes with a change in the opening of the throttle valve 4.

The provisional target throttle opening t-TAtg
Is in the dead area 45 (step 103, Ye
s), the ECU 30 calculates the tentative target throttle opening degree t-TAt
It is determined whether or not g is less than the drift suppression throttle opening TA _imin, that is, whether or not the temporary target throttle opening t-TAtg falls within the drift measurement error region 46 (step 10).
5). As described with reference to the graph of FIG. 5B, the provisional target throttle opening degree t-TAtg is different from the drift measurement error region 4.
6 (step 105, Yes), the ECU 30
Sets the target throttle opening TAtg to the drift suppression throttle opening TA _imin (step 106), and controls the drive of the throttle actuator 5 to adjust the opening of the throttle valve 4 to the target throttle opening TAtg.

In this case, since the target throttle opening TAtg is set to the drift suppression throttle opening TA _imin which is larger than the drift measurement error region 46, drift in the intake pipe 2 does not occur, and the measurement error of the air flow meter 24 is _reduced. Will not occur. Further, the target throttle opening TAtg is set in the insensitive region 4.
5, the target throttle opening TAtg
Is set to a value different from the tentative target throttle opening t-TAtg (drift suppression throttle opening TA _imin ), the intake air amount hardly changes and the operating state of the engine 1 is not affected.

Further, the provisional target throttle opening degree t-TAtg
Is not in the drift measurement error area 46 (step 105, No), the ECU 30 determines whether the provisional target throttle opening t-TAtg exceeds the pulsation suppression throttle opening TA _imax , that is, the provisional target throttle opening t It is determined whether or not -TAtg falls within the pulsation measurement error area 47 (step 107).

The tentative target throttle opening degree t-TAtg has already been obtained.
Enters the dead zone 45 (step 103, Yes),
It is out of the drift measurement error region 46 (step 10).
5, No). If it further deviates from the pulsation measurement error area 47 (Step 107, No),
As described with reference to the graph (b), if the provisional target throttle opening degree t-TAtg enters the dead area 45 and deviates from the drift measurement error area 46 and the pulsation measurement error area 47, the ECU 30 sets the target throttle The opening degree TAtg is set to the provisional target throttle opening degree t-TAtg (step 1).
04) By controlling the driving of the throttle actuator 5, the opening of the throttle valve 4 is adjusted to the target throttle opening TAtg.

In this case, since the target throttle opening TAtg deviates from the drift measurement error area 46 and the pulsation measurement error area 47, no measurement error occurs in the air flow meter 24. Further, since the target throttle opening TAtg is set in the dead zone 45, the intake air amount hardly changes even if the opening of the throttle valve 4 changes.

As described with reference to the graph of FIG. 5B, if the provisional target throttle opening t-TAtg falls within the pulsation measurement error area 47 (step 107, Ye).
s), the ECU 30 sets the target throttle opening TAtg to the pulsation suppression throttle opening TA _{im ax} (step 10).
8) By controlling the drive of the throttle actuator 5, the opening of the throttle valve 4 is adjusted to the target throttle opening TAtg.

In this case, since the target throttle opening TAtg is set to the pulsation suppressing throttle opening TA _imax smaller than the pulsation measurement error area 47, the pulsation of the pressure in the intake pipe 2 does not occur, and the measurement of the air flow meter 24 is performed. No error occurs. Also, since the target throttle opening TAtg is set within the dead zone 45, the target throttle opening Ttg is set.
Even if Atg is set to a value (pulsation suppression throttle opening TA _imax ) different from the provisional target throttle opening t-TAtg,
The intake air amount hardly changes, and does not affect the operation state of the engine 1.

As described above, in the present embodiment, the dead throttle opening TA _PMWOT , the drift suppression throttle opening TA _imin and the pulsation suppression throttle opening TA _imax are determined according to the engine speed NE and the opening / closing timing Vt of the intake / exhaust valve.
When the target throttle opening degree TAtg is set within the dead area 45, the target throttle opening degree TAtg is determined by determining the sensitive area 44, the dead area 45, the drift measurement error area 46, and the pulsation measurement error area 47. It is set out of the measurement error area 46 and the pulsation measurement error area 47. As a result, it is possible to prevent a measurement error of the air flow meter 24 due to a pulsation or a drift of the pressure in the intake pipe 2 without substantially changing the air intake amount. As a result, various controls performed based on the amount of intake air measured by the air flow meter 24 can be accurately performed. For example, control of the fuel injection amount and control of the ignition timing can be performed accurately.

In the present embodiment, the drift suppression throttle opening TA _imin and the pulsation suppression throttle opening TA
_{imax is set} to the drift measurement error area 46 and the pulsation measurement error area 47
However, if it is within the insensitive region 45 and _deviates from the drift measurement error region 46 and the pulsation measurement error region 47, the drift suppression throttle opening TA _imin and the pulsation suppression throttle opening TA _imax are set. Any value may be set.

If the drift measurement error area 46 can be substantially ignored, the target throttle opening TAt
By only keeping g less than the dead throttle opening TA _PMWOT , the target throttle opening TAtg can be set outside the pulsation measurement error region 47 with little change in the intake air amount. In this case, the target throttle opening TA
tg does not need to be adjusted unnecessarily in the dead area 45. Alternatively, the target throttle opening TAtg may be set outside the pulsation measurement error region 47 only by suppressing the target throttle opening TAtg to be equal to or less than the pulsation suppression throttle opening TA _imax .

[0046]

As described above, according to the present invention, the target throttle opening is within the dead opening range where the change in the actual throttle opening does not substantially affect the intake air amount. At times, the target throttle opening is corrected within the dead opening region and outside the error opening region that causes a measurement error of the flow meter. That is, as long as the actual throttle opening changes within the dead opening region, the intake air amount does not substantially change. Therefore, when the target throttle opening is in the dead opening region, the target throttle opening is set to the flow meter. The measurement error of the flow meter is corrected outside the error opening range, thereby preventing the measurement error of the flow meter without substantially changing the intake air amount.

According to one embodiment, the target throttle opening is corrected to the predetermined opening at the boundary of the dead opening region, so that the target throttle opening is not unnecessarily adjusted within the dead opening region. .

According to one embodiment, the target throttle opening is corrected to an opening at which the measurement error of the flow meter outside the error opening region becomes small, so that the measurement error of the flow meter becomes small.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a throttle control device of the present invention.

FIG. 2 is a flowchart showing opening / closing control of a throttle valve in the apparatus of FIG. 1;

FIG. 3 is a diagram showing a data table storing base values corresponding to an engine speed NE and opening / closing timings Vt of intake and exhaust valves.

FIG. 4 is a graph showing a throttle opening degree TA with respect to an engine speed NE when an arbitrary opening / closing timing Vt is set.

5A is a graph showing an actual intake air amount with respect to a throttle opening TA, and FIG. 5B is a graph showing a target throttle opening TAt with respect to a tentative target throttle opening t-TAtg.
It is a graph which shows g.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal combustion engine (engine) 2 Intake pipe 3 Exhaust pipe 4 Throttle valve 5 Throttle actuator 8 Cylinder 9 Piston 10 Connecting rod 11 Crankshaft 12 Cylinder head 13 Combustion chamber 14 Intake valve 15 Exhaust valve 17 Intake port 18 Injector 19 Spark plug 21 Water temperature sensor 22 Reference Position Sensor 23 Speed Sensor 24 Air Flow Meter 25 Accelerator Pedal 26 Accelerator Sensor 27 Variable Valve Timing Mechanism 28 Shift Sensor 30 ECU

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naoto Kushi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 3G065 CA39 DA04 FA09 FA12 GA05 GA07 GA10 GA14 GA15 GA31 GA41 GA46 KA36 3G301 HA19 JA08 JA13 JB09 LA03 LA07 NA08 NB05 ND02 NE25 PA04Z PA11A PA11Z PD15Z PE01Z PE03Z PE04Z PE08Z PE10Z PF03Z PF07Z

Claims (3)

[Claims] An internal combustion engine provided with a flow meter upstream of a throttle valve and controlled based on an intake air amount measured by the flow meter, wherein a target opening of the throttle valve is determined based on an engine operating state. A throttle control device for an internal combustion engine that controls the throttle valve so that the actual throttle opening becomes a target throttle opening, wherein the change in the actual throttle opening substantially affects the intake air amount. When the target throttle opening is within the dead opening region where the target throttle opening is not given, the opening to correct the target throttle opening within the dead opening region and outside the error opening region related to the measurement error of the flow meter. A throttle control device for an internal combustion engine, comprising a correction unit. 2. The internal combustion engine according to claim 1, wherein the dead opening region is a region equal to or larger than a predetermined opening, and the opening correction means corrects the target throttle opening to the predetermined opening. Throttle control device. 3. The error opening area is an area which causes a measurement error of the flow meter, and the opening correction means measures the target throttle opening by measuring the flow meter outside the error opening area. 2. The throttle control device for an internal combustion engine according to claim 1, wherein the opening is corrected to an opening that reduces the error.