JP2002089338A - Fuel injection control device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Problem] An intake air flow rate Q detected by an air flow meter
In the fuel injection control device for estimating the intake pipe pressure from a, the air-fuel ratio control accuracy is prevented from deteriorating due to the opening and closing of the tumble control valve. An open / close state of a tumble control valve is determined by comparing an opening degree of the tumble control valve with a predetermined value. Then, the smoothing coefficient KTMGN used when estimating the intake pipe pressure from the intake air flow rate Qa is set to a different value according to the opening and closing of the tumble control valve, and the smoothing coefficient KTMG
An intake pipe pressure estimated value PMMHG is calculated from the pressure gradient constant KTM set using N and the intake air flow rate Qa. Furthermore,
From the intake pipe pressure estimated value PMMHG, the cylinder intake air amount QAR
Is calculated, and the basic fuel injection amount TP is calculated based on the cylinder intake air amount QAR.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control device for an internal combustion engine, and more particularly to a fuel injection control device for an internal combustion engine provided with a drift control valve downstream of a throttle valve that causes a drift in intake air when the throttle valve is closed. Related to quantity control technology.

[0002]

2. Description of the Related Art Conventionally, there has been known an internal combustion engine in which a deflected flow control valve for generating a tumble flow or a swirl flow in a cylinder by deflected intake air is interposed in an intake pipe downstream of a throttle valve. See Japanese Unexamined Patent Publication No. Hei 7-293304 and Japanese Unexamined Patent Publication No. Hei 7-259573.

Further, as a fuel injection device for an internal combustion engine, a fuel injection amount corresponding to a cylinder intake air amount is calculated based on an intake air flow rate detected by an air flow meter and an intake pipe pressure detected by an intake pressure sensor. There has been known a configuration in which an intake pipe pressure is estimated from an intake air flow rate detected by an air flow meter to calculate a fuel injection amount.

[0004]

In an engine equipped with the above-mentioned drift control valve, when the drift control valve is closed in order to generate a tumble flow or a swirl flow in the cylinder, the engine is not operated. A phase shift may occur between the upstream intake pipe pressure and the downstream intake pipe pressure.

In the open state of the drift control valve, the pressure before and after the drift control valve changes in accordance with the operation of the throttle as shown in FIG. 10, but in the closed state of the drift control valve, for example, When the throttle valve is opened, until the opening area of the throttle valve exceeds the opening area of the drift control valve, as shown in FIG. 10, the intake pipe pressures P1 and P2 upstream and downstream of the drift control valve substantially increase. However, after the opening area of the throttle valve exceeds the opening area of the drift control valve, the downstream intake pipe pressure P2 is delayed with respect to the change of the upstream intake pipe pressure P1.

Accordingly, for example, in a fuel injection control device that detects the intake pipe pressure upstream of the drift control valve to calculate the fuel injection amount, the transient cylinder control valve changes the actual cylinder intake air amount during a transient state when the drift control valve is closed. The upstream intake pipe pressure P higher (the negative pressure is smaller) than the corresponding downstream intake pipe pressure P2
As a result, the fuel injection amount is calculated on the basis of 1, and the air-fuel ratio shifts to the rich side.

In the case of a configuration in which the intake pipe pressure is estimated from the intake air flow rate detected by the air flow meter and the fuel injection amount is calculated based on the estimated intake pipe pressure, the fuel injection amount is calculated when the drift control valve is closed. When the intake pipe pressure is estimated with the characteristic of slow transient response, the air-fuel ratio becomes lean when the drift control valve is opened, and conversely, the intake pipe pressure is estimated by adapting when the drift control valve is opened. If this is done, the air-fuel ratio will become rich when the drift control valve is closed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and when a drift control valve that causes a drift of intake air is closed, a phase shift of the intake pipe pressure occurs between the upstream and downstream of the drift control valve. Accordingly, it is an object of the present invention to provide a fuel injection control device for an internal combustion engine that can calculate a fuel injection amount corresponding to an actual cylinder intake air amount.

[0009]

Therefore, according to the first aspect of the present invention, a fuel injection control device is configured to calculate a fuel injection amount based on a state quantity of intake air detected upstream of a drift control valve. In this configuration, the correction is made in accordance with the opening and closing of the drift control valve. According to such a configuration,
When detecting the state quantity of intake air such as intake pipe pressure or intake air flow rate upstream of the drift control valve that generates a tumble flow or swirl flow in the cylinder, is it the time of opening the drift control valve? Depending on whether the valve is closed or not, the phase state between the detected state quantity and the state quantity on the downstream side of the drift control valve corresponding to the cylinder intake air amount changes. Correction is made in the calculation of the fuel injection amount.

According to a second aspect of the present invention, an air flow meter for detecting an intake air flow rate is provided upstream of the throttle valve, and a fuel injection amount is calculated based on the intake air flow rate detected by the air flow meter. Thus, the transient response gain of the fuel injection amount with respect to the detected value of the intake air flow rate is switched according to the opening and closing of the drift control valve.

According to this configuration, the fuel injection amount is calculated based on the intake air flow rate detected by the air flow meter provided on the upstream side of the throttle valve.
Depending on whether the drift control valve is open or closed, the transient response gain in the calculation of the fuel injection amount is switched, and the responsiveness of the fuel injection amount to a change in the detected value of the intake air flow rate is switched. .

According to the third aspect of the present invention, the intake pipe pressure downstream of the throttle valve is estimated based on the intake air flow rate detected by an air flow meter provided upstream of the throttle valve, and the estimated intake pipe pressure is estimated. And calculating the fuel injection amount based on the intake pipe pressure and / or calculating the fuel injection amount based on the intake pipe pressure, in accordance with the opening and closing of the drift control valve. .

According to this configuration, the estimation of the intake pipe pressure based on the intake air flow rate detected by the air flow meter is corrected in accordance with the opening and closing of the drift control valve, or is estimated regardless of the opening and closing of the drift control valve. In the calculation of the fuel injection amount based on the estimated value of the intake pipe pressure (for example, which has been appropriately estimated when the valve is opened), a correction corresponding to the opening and closing of the drift control valve is added.

According to a fourth aspect of the present invention, the transient response gain in estimating the intake pipe pressure is switched according to the opening and closing of the drift control valve. According to this configuration, when the drift control valve is closed, the transient response gain in the estimation of the intake pipe pressure is changed in response to the occurrence of a phase shift in the intake pipe pressure between the upstream and downstream of the drift control valve. Switching is performed depending on whether the valve is open or closed.

According to the fifth aspect of the present invention, the transient response gain of the drift control valve when the valve is closed is made smaller than the transient response gain when the valve is opened. According to such a configuration,
During acceleration in the closed state of the drift control valve, it corresponds to the cylinder intake air amount, in response to a delay in the response of the downstream intake pipe pressure to a change in the intake pipe pressure upstream of the drift control valve. It is possible to estimate the intake pipe pressure downstream of the drift control valve.

According to a sixth aspect of the present invention, there is provided an intake pressure sensor for detecting an intake pipe pressure downstream of the throttle valve and upstream of the drift control valve, and the fuel is detected based on the intake pipe pressure detected by the intake pressure sensor. In this configuration, the injection amount is calculated, and correction is performed according to the opening and closing of the drift control valve. According to this configuration, the intake pipe pressure detected by the intake pressure sensor, when the drift control valve is opened,
Same as the intake pipe pressure downstream of the drift control valve, but
When the drift control valve is closed, a phase shift occurs with respect to the intake pipe pressure on the downstream side of the drift control valve. Therefore, the estimation error of the cylinder intake air amount due to the phase shift is corrected.

According to a seventh aspect of the present invention, in the fuel injection amount calculation based on the intake pipe pressure, at least the charging efficiency is corrected, the charging efficiency is corrected in accordance with the opening and closing of the drift control valve. The configuration was set individually. According to this configuration, the intake pipe pressure on the downstream side of the throttle valve is estimated based on the intake air flow rate detected by the air flow meter, or the intake pipe pressure is detected by the sensor on the upstream side of the drift control valve, and the intake pipe pressure is detected. In the configuration in which the fuel injection amount is calculated based on the pressure, the filling efficiency is corrected when the fuel injection amount is calculated based on the intake pipe pressure. Phase shift occurs in the intake pipe pressure, and apparently,
Since the charging efficiency is reduced, the correction of the charging efficiency is set to a different value according to the opening / closing of the drift control valve.

According to an eighth aspect of the invention, the opening and closing of the drift control valve is determined based on whether or not the opening of the drift control valve is equal to or less than a reference opening. With this configuration, if the opening of the drift control valve is equal to or less than the reference opening, it is determined that the valve is closed when a phase shift of the intake pipe pressure occurs before and after the drift control valve.

[0019]

According to the first aspect of the present invention, it is determined whether or not there is a phase difference in the intake pipe pressure between the upstream and downstream of the drift control valve, and the fuel injection amount is corrected. There is an effect that air-fuel ratio control accuracy can be ensured both when the control valve is opened and when the control valve is closed, and deterioration in exhaust properties and deterioration in driving performance due to air-fuel ratio deviation can be prevented.

According to the second aspect of the present invention, in the configuration in which the fuel injection amount is calculated based on the intake air flow rate detected by the air flow meter, a response characteristic corresponding to the occurrence of a phase shift when the drift control valve is closed is provided. Thus, the transient response gain in the calculation of the fuel injection amount is switched, so that there is an effect that the fuel injection amount corresponding to the actual cylinder intake air amount can always be calculated.

According to the third aspect of the present invention, in the configuration for estimating the intake pipe pressure based on the intake air flow rate detected by the air flow meter, the intake pipe pressure on the downstream side of the drift control valve corresponding to the cylinder intake air amount is determined. There is an effect that the corresponding fuel injection amount can always be calculated. According to the fourth and fifth aspects of the present invention, the transient response in estimating the intake pipe pressure is changed according to the phase difference of the intake pipe pressure generated between the upstream and downstream of the drift control valve when the drift control valve is closed. Thus, there is an effect that the intake pipe pressure corresponding to the actual cylinder intake air amount can be estimated.

According to the sixth aspect of the present invention, the fuel injection according to the intake pipe pressure corresponding to the cylinder intake air amount downstream of the drift control valve, based on the detected value of the intake pipe pressure upstream of the drift control valve. The effect is that the quantity can be calculated. According to the seventh aspect of the present invention, the fuel injection amount corresponding to the phase difference of the intake pipe pressure when the drift control valve is closed is calculated by correcting the charging efficiency used for calculating the fuel injection amount based on the intake pipe pressure. There is an effect that can be.

According to the eighth aspect of the invention, there is an effect that the valve closing state where a phase difference occurs in the intake pipe pressure before and after the drift control valve can be accurately determined.

[0024]

Embodiments of the present invention will be described below. FIG. 1 is a system configuration diagram of an internal combustion engine according to the embodiment. In FIG. 1, air filtered by an air cleaner 2 is sucked into a combustion chamber of each cylinder of an internal combustion engine 1 mounted on a vehicle via an intake pipe 3.

The intake air amount of the engine 1 is adjusted by a throttle valve 4 provided in the intake pipe 3. An electromagnetic fuel injection valve 5 is provided at an intake port of each cylinder, and a mixture is formed by the fuel injected from the fuel injection valve 5 and the intake air. The air-fuel mixture introduced into the combustion chamber is ignited and combusted by an ignition plug 6, and the exhaust gas is exhausted from an exhaust pipe 7, purified by a catalyst 8 interposed in the exhaust pipe 7, and then released into the atmosphere. Is done.

A tumble control valve (deviation control valve) 9 for generating a tumble flow in the cylinder is provided in an intake pipe downstream of the throttle valve 4 and upstream of the fuel injection valve 5. The tumble control valve 9 has a valve body in which a part of a disk-shaped valve is cut out, and when the valve is closed, the intake air flows only through the notch, thereby causing a drift in the intake air. Thus, a tumble flow is generated in the cylinder.

The tumble control valve 9 is opened and closed by a DC motor 10. In the present embodiment, the configuration is provided with the tumble control valve 9 that generates a tumble flow. However, instead of the tumble control valve 9, a configuration that includes a swirl control valve that generates a swirl flow in a cylinder may be used. . That is, any valve may be used as long as it controls the flow of intake air in the cylinder by deviating the intake air, and does not limit the direction of the swirling flow generated in the cylinder.

The control unit 20 includes a CPU, R
A microcomputer including an OM, a RAM, an A / D converter, an input / output interface, and the like is provided. The microcomputer receives input signals from various sensors and performs arithmetic processing based on the signals.
The operation of the fuel injection valve 5, ignition plug 6, and DC motor 10 is controlled. As the various sensors, a crank angle sensor 21 for detecting a crank angle of the engine 1 and a cam sensor 22 for extracting a cylinder discrimination signal from a cam shaft are provided. Based on a signal from the crank angle sensor 21, the rotation speed Ne of the engine is determined. Is calculated.

In addition, an air flow meter 23 for detecting the intake air flow rate (mass flow rate) Qa upstream of the throttle valve 4, a tumble opening sensor 24 for detecting the opening degree of the tumble control valve 9 by a potentiometer, and a throttle valve 4 Throttle sensor 25 for detecting opening TVO, water temperature sensor 2 for detecting cooling water temperature Tw of engine 1
6. An air-fuel ratio sensor 27 for detecting the air-fuel ratio of the combustion mixture in accordance with the oxygen concentration in the exhaust gas, a vehicle speed sensor 28 for detecting the vehicle speed VSP, and the like are provided.

Here, the opening / closing control of the tumble control valve 9 by the control unit 20 will be described with reference to the flowchart of FIG. In the flowchart of FIG. 2, in step S1, it is determined whether or not the water temperature Tw at the time of starting the engine 1 is within a predetermined temperature range. If the starting water temperature Tw is within the predetermined temperature range, the process proceeds to step S2, and it is determined whether or not the engine rotation speed Ne is equal to or lower than a predetermined rotation.

If the engine rotation speed Ne is equal to or less than the predetermined rotation, the process proceeds to step S3, and it is determined whether or not the engine load is within a predetermined range. In the present embodiment, the basic fuel injection amount TP calculated as described later is used as a parameter representing the engine load, but another parameter may be used.

If the engine load is within the predetermined range, the process proceeds to step S4, where it is determined whether the vehicle speed is equal to or lower than the predetermined speed. If the vehicle speed is equal to or less than the predetermined speed, the process proceeds to step S5, and it is determined whether the elapsed time from the start is equal to or less than the predetermined time. If the elapsed time from the start is equal to or shorter than the predetermined time, the process proceeds to step S6, and the opening degree T of the throttle valve 4 is set.
It is determined whether VO is equal to or less than a predetermined opening.

If the opening TVO is equal to or smaller than the predetermined opening, the process proceeds to step S7, where the tumble control valve 9
Is closed (ON). On the other hand, if at least one of steps S1 to S6 does not hold, the process proceeds to step S8.
The tumble control valve 9 is opened (OFF). Next, the calculation of the fuel injection amount by the control unit 20 will be described below.

The basic fuel injection amount (basic injection time) TP
Is calculated according to the following equation. TP = TPFGN × (tp−tpold) + tpold tp = KTI × (QAR / 14.7) × (TDATF /
2) In the above equation, TPFGN is a gain, tpold is a previous value of tp, KTI is an injector constant, QAR is a cylinder intake air amount (g / min), TDATF is an engine rotation cycle,
4.7 indicates a stoichiometric air-fuel ratio as a target air-fuel ratio.

The above tp is required for forming a mixture having a stoichiometric air-fuel ratio with respect to the amount of air (mass) sucked into the cylinder while the engine 1, which is a four-cylinder engine, rotates at a crank angle of 180 °. Injection amount. However, when any of the following conditions is not satisfied, TP = tp. (1) Idle switch ON (throttle valve fully closed) (2) Neutral switch OFF Accordingly, the filter processing for changing the basic fuel injection amount TP with the gain TPFGN in response to the injection amount tp is performed when the idle switch is ON and the neutral switch is OFF. In other cases, the injection amount corresponding to the cylinder intake air amount QAR is directly used as the basic fuel injection amount T
P.

The cylinder intake air amount QAR is calculated as follows. QAR = KST × HKST × KSV × PMMHG / TD
ATA In the above equation, PMMHG is the estimated intake pipe pressure, KSV is the displacement of the engine 1, KST is the charging efficiency correction coefficient set in accordance with the intake air temperature, and HKST is set from the engine speed and the estimated intake pipe pressure PMMHG. Is a filling efficiency correction coefficient to be calculated.

The estimated intake pipe pressure value PMMHG is calculated as follows. PMMHG = pmmhg + KTM × (Qa-QAR) /
KIMV In the above equation, pmmhg is the previous value of PMMHG, KTM is the pressure gradient constant, KIMV is the intake manifold volume, and Qa is the intake air flow rate Qa detected by the air flow meter 23.

The pressure gradient constant KTM is calculated as follows. KTM = KTMC × KTMGN × KKTMTW where KTMC is a basic value, KTMGN is a smoothing coefficient,
KKTMTW is a correction coefficient based on the intake air temperature. As described above, in the present embodiment, the throttle valve 4 is controlled based on the intake air flow rate Qa detected by the air flow meter 23.
A downstream intake pipe pressure is estimated, a cylinder intake air amount QAR is calculated from the estimation result, and the cylinder intake air amount QA is calculated.
The basic fuel injection amount TP is calculated based on R.

Here, when the tumble control valve 9 is closed, in order to cope with a phase difference of the intake pipe pressure between upstream and downstream of the tumble control valve 9, as shown in the flowchart of FIG. The smoothing coefficient KTMGN, which determines the transient response gain in estimating the pipe pressure, is switched according to the opening and closing of the tumble control valve 9 to calculate the fuel injection amount.

In the flowchart of FIG. 3, in step S21, various parameters such as the rotation Ne, the intake air flow rate Qa, the opening of the tumble control valve, the throttle opening TVO, the vehicle speed, and the water temperature are read. In step S22,
It is determined whether the tumble control valve 9 is open or closed. The opening / closing of the tumble control valve 9 is determined as shown in the flowchart of FIG.

In step S51, the opening of the tumble control valve 9 detected by the tumble opening sensor 24 is input. In step S52, the opening of the tumble control valve 9 detected by the tumble opening sensor 24 is set to a predetermined value. It is determined whether it is equal to or less than the degree (reference opening degree). If the opening of the tumble control valve 9 is equal to or less than the predetermined opening, the process proceeds to step S53, where the tumble control valve 9 is closed (ON).
If it is determined that the tumble control valve 9 is in the state and the opening of the tumble control valve 9 exceeds the predetermined opening, the process proceeds to step S54, and it is determined that the tumble control valve 9 is in the open (OFF) state.

Incidentally, for simplicity, the opening / closing of the tumble control valve 9 may be determined based on the opening / closing command according to the flowchart of FIG. In step S22,
If it is determined that the tumble control valve 9 is to be opened (OFF), the process proceeds to step S23, where the smoothing coefficient KT is set.
As the MGN, a value KTMGNOFF stored in advance as a value suitable for opening the tumble control valve 9 is set.

On the other hand, if it is determined in step S22 that the tumble control valve 9 is closed (ON), the process proceeds to step S25, where the smoothing coefficient KTMGN is applied when the tumble control valve 9 is closed. A value KTMGNON stored in advance is set as a value to be performed. When the tumble control valve 9 is accelerated in the open state, the influence of the tumble control valve 9 is negligible and the intake pipe pressure changes with a relatively high response, whereas when the tumble control valve 9 is closed, the cylinder intake air The intake pipe pressure downstream of the tumble control valve 9 corresponding to the amount changes later than the upstream side, and as a result, the response of the intake pipe pressure corresponding to the cylinder intake air amount becomes slower than when the valve is opened. (See FIG. 10).

Therefore, when the smoothing coefficient KTMGNOFF is set to, for example, 1.0 and the smoothing coefficient KTMGNON is set to 0.7 to 0.8, the change in the estimated intake pipe pressure value PMMHG with respect to the change in the intake air flow rate Qa depends on when the tumble control valve 9 is closed. I am trying to be late. Therefore, even when the response of the intake pipe pressure downstream of the tumble control valve 9 corresponding to the cylinder intake air amount is delayed when the tumble control valve 9 is closed, the intake pipe corresponding to the actual cylinder intake air amount The pressure estimation value PMMHG can be calculated, and even when the tumble control valve 9 is closed, the air-fuel ratio control accuracy can be ensured and the exhaust properties and operating performance can be maintained well.

In step S23, the smoothing coefficient KTMGNO
When FF is selected, in step S24, the pressure gradient constant KTM is calculated using the smoothing coefficient KTMGNOFF.
Is calculated as KTM = KTMC × KTMGNOFF × KKTMTW, an intake pipe pressure estimated value PMMHG is calculated based on the pressure gradient constant KTM, and further, a cylinder intake air amount QAR is calculated based on the intake pipe pressure estimated value PMMHG. .

On the other hand, in step S25, the smoothing coefficient KTM
When GNON is selected, in step S26, the pressure gradient constant KT is calculated using the smoothing coefficient KTMGONN.
M is calculated as KTM = KTMC × KTMGNON × KKTMTW, an intake pipe pressure estimated value PMMHG is calculated based on the pressure gradient constant KTM, and a cylinder intake air amount QAR is further calculated based on the intake pipe pressure estimated value PMMHG. I do.

The pressure gradient constant KTM, which is calculated when the tumble control valve 9 is opened, may be reduced when the tumble control valve 9 is closed. , The transient response of the estimated intake pipe pressure value PMMHG to the intake pipe pressure is switched according to the opening and closing of the tumble control valve 9.
The same operation as in the above-described embodiment for switching the MGN is achieved.

In step S27, the cylinder intake air amount QAR calculated in step S24 or step S26.
Is calculated based on the basic fuel injection amount TP. In step S28, the basic fuel injection amount TP is corrected with a correction coefficient based on water temperature, an acceleration increase coefficient, an air-fuel ratio feedback correction coefficient, and the like, to calculate a final fuel injection amount TI. In step S29, the calculated fuel injection amount TI is calculated. The fuel injection amount TI is stored in a register.

The flowchart of FIG. 5 shows a second embodiment of the fuel injection amount calculation. Here, a charging efficiency correction coefficient H used for calculating the cylinder intake air amount QAR is shown.
The KST is switched according to the opening and closing of the tumble control valve 9. In the flowchart of FIG.
In step S31, various parameters are read in the same manner as in step S21. In step S32, the opening and closing of the tumble control valve 9 is determined in the same manner as in step S22.

In step S32, the tumble control valve 9
When it is determined that the valve is open, the routine proceeds to step S33, in which a reference is made to a map storing a value HKSTOFF suitable when the tumble control valve 9 is opened as the charging efficiency correction coefficient HKST, and the engine speed at that time is referred to. Filling efficiency correction coefficient H corresponding to speed and intake pipe pressure estimated value PMMHG
Search for KSTOFF.

On the other hand, if it is determined in step S32 that the tumble control valve 9 is closed, step S32 is executed.
35, the value HKSTON suitable as the filling efficiency correction coefficient HKST when the tumble control valve 9 is closed.
Is referred to, and a charging efficiency correction coefficient HKSTON corresponding to the engine speed and the intake pipe pressure estimated value PMMHG at that time is searched.

As shown in FIGS. 6 and 7, the map of the charging efficiency correction coefficient HKSTON and the charging efficiency correction coefficient HKSTOFF indicates that the charging efficiency increases as the engine rotation speed increases and the estimated intake pipe pressure value PMMHG increases. Although a larger value is stored as the correction coefficient, the charging efficiency correction coefficient HK is different from the charging efficiency correction coefficient HKSTOFF.
STON is set to a smaller value.

When the tumble control valve 9 is closed, the amount of cylinder intake air during transition is smaller than when the tumble control valve 9 is opened due to the phase difference between before and after the tumble control valve 9. This can be regarded as a state in which the charging efficiency is apparently reduced with reference to the intake pipe pressure on the upstream side of the tumble control valve 9. Therefore, the filling efficiency correction coefficient HKST is switched in accordance with the opening and closing of the tumble control valve 9, so that the filling efficiency when the tumble control valve 9 is closed is set smaller.

As described above, the charging efficiency correction coefficient HK
When ST is set to a different value according to the opening and closing of the tumble control valve 9, in steps S34 and S36,
The pressure gradient constant KTM and the estimated intake pipe pressure PMMH
G is calculated as a common value when the tumble control valve 9 is opened and closed, while the intake pipe pressure estimated value PMMH is calculated.
In the calculation of the cylinder intake air amount QAR based on G, a filling efficiency correction coefficient HKST set to a different value according to the opening and closing of the tumble control valve 9 is used.

In step S37, the cylinder intake air amount QAR calculated in step S34 or step S36.
Is calculated based on the basic fuel injection amount TP. In step S38, the basic fuel injection amount TP is corrected by a correction coefficient based on water temperature, an acceleration increase coefficient, an air-fuel ratio feedback correction coefficient, and the like, to calculate a final fuel injection amount TI. In step S39, the calculated fuel injection amount TI is calculated. The fuel injection amount TI is stored in a register.

Instead of setting the filling efficiency correction coefficient HKST from a different map according to the opening and closing of the tumble control valve 9, for example, the filling efficiency correction coefficient HKST corresponding to the time when the tumble control valve 9 is opened is replaced by the tumble control valve 9. May be reduced when the valve is closed, or
The filling efficiency correction coefficient KST may be set from a different table according to the opening and closing of the tumble control valve 9, and the cylinder intake air amount QAR calculated based on the intake pipe pressure estimated value PMMHG is determined when the tumble control valve 9 is closed. It is sufficient if the correction becomes smaller.

When an intake pressure sensor 29 for detecting the intake pipe pressure PB is provided downstream of the throttle valve 4 and upstream of the tumble control valve 9, as shown in FIG. If the intake pipe pressure PB detected by the intake pressure sensor 29 is substituted for the intake pipe pressure estimated value PMMHG in the arithmetic expression of QAR, the cylinder intake air amount QAR can be calculated, and the cylinder intake air amount QAR The basic fuel injection amount TP can be similarly calculated.

However, also in this case, when the tumble control valve 9 is closed, the phase of the intake pipe pressure downstream of the tumble control valve 9 is shifted with respect to the intake pipe pressure PB detected by the intake pressure sensor 29, The calculation accuracy of the cylinder intake air amount QAR is reduced. Therefore, in the configuration including the intake pressure sensor 29, similarly to the embodiment illustrated in the flowchart of FIG. 5, it is preferable to switch the charging efficiency correction coefficient. This is shown in the flowchart of FIG.

In the flowchart of FIG. 9, in step S41, various parameters including the intake pipe pressure PB detected by the intake pressure sensor 29 are read, and in step S4.
In step 2, it is determined whether the tumble control valve 9 is open or closed in the same manner as in step S22. If it is determined in step S42 that the tumble control valve 9 is being opened, step S42 is executed.
43, the value HKSTOF suitable as the filling efficiency correction coefficient HKST when the tumble control valve 9 is opened.
Referring to a map storing F, a charging efficiency correction coefficient HKS corresponding to the engine speed and the intake pipe pressure PB at that time.
Search for TOFF.

On the other hand, if it is determined in step S42 that the tumble control valve 9 is closed, step S42 is executed.
45, the value HKSTON suitable as the filling efficiency correction coefficient HKST when the tumble control valve 9 is closed.
Is referred to, and a charging efficiency correction coefficient HKST corresponding to the engine speed and the intake pipe pressure PB at that time is referred to.
Search for ON.

As described above, the charging efficiency correction coefficient HK
When ST is set to a different value according to the opening and closing of the tumble control valve 9, in steps S44 and S46,
The cylinder intake air amount QAR is calculated based on the charging efficiency correction coefficient HKST set to a different value according to the opening and closing of the tumble control valve 9 and the intake pipe pressure PB. In step S47, the basic fuel injection amount TP is calculated based on the cylinder intake air amount QAR calculated in step S44 or step S46.

In step S48, the basic fuel injection amount TP is corrected by a correction coefficient based on water temperature, an acceleration increase coefficient, an air-fuel ratio feedback correction coefficient, and the like, to calculate a final fuel injection amount TI. , The calculated fuel injection amount TI is stored in a register. In the configuration including the air flow meter 23 shown in FIG. 1, the intake pipe pressure was estimated from the intake air flow rate Qa detected by the air flow meter 23, and the cylinder intake air amount was obtained from the intake pipe pressure. In a configuration in which the cylinder intake air amount (basic fuel injection amount) is directly obtained from the intake air flow rate Qa detected by the meter 23 and the engine speed, the cylinder intake air amount (basic fuel injection amount) is calculated based on the weighted average value of the air flow meter 23. Injection amount) may be calculated, and the weighting (transient response gain) in the weighted average may be switched according to the opening and closing of the tumble control valve 9.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an internal combustion engine according to an embodiment.

FIG. 2 is a flowchart illustrating opening / closing control of a tumble control valve according to the embodiment.

FIG. 3 is a flowchart showing a calculation of a fuel injection amount in the embodiment.

FIG. 4 is a flowchart illustrating a determination on opening / closing of a tumble control valve according to the embodiment.

FIG. 5 is a flowchart showing another embodiment of the fuel injection amount calculation.

FIG. 6 is a diagram showing a map of a charging efficiency correction coefficient referred to in the processing shown in the flowchart of FIG. 5;

FIG. 7 is a view showing a map of a charging efficiency correction coefficient referred to in the processing shown in the flowchart of FIG. 5;

FIG. 8 is a system configuration diagram of an internal combustion engine showing an embodiment including an intake pressure sensor.

FIG. 9 is a flowchart showing a fuel injection amount calculation using an intake pressure sensor.

FIG. 10 is a time chart showing a conventional problem.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 3 ... Intake pipe 4 ... Throttle valve 5 ... Fuel injection valve 6 ... Spark plug 9 ... Tumble control valve 10 ... DC motor 20 ... Control unit 21 ... Crank angle sensor 23 ... Air flow meter 24 ... Tumble opening sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 43/00 301 F02D 43/00 301H 301U 45/00 364 45/00 364D 366 366F F-term (Reference) 3G084 BA13 BA21 DA04 DA10 DA25 FA05 FA07 FA10 FA11 FA20 FA29 FA33 FA38 3G301 HA01 JA03 JA21 LA05 MA12 MA13 PA00Z PA01Z PA07Z PA11Z PD03Z PE01Z PE03Z PE05Z PE08Z PF01Z

Claims (8)

[Claims] 1. A fuel injection control device for an internal combustion engine, comprising a drift control valve for causing a drift in intake air when the throttle valve is closed, the intake air being detected upstream of the drift control valve. A fuel injection control device for an internal combustion engine, wherein the fuel injection amount is calculated based on the state quantity of the fuel injection amount, and a correction according to the opening and closing of the drift control valve is performed in the calculation of the fuel injection amount. . 2. An air flow meter for detecting an intake air flow rate on an upstream side of the throttle valve, wherein a fuel injection amount is calculated based on the intake air flow rate detected by the air flow meter. 2. The fuel injection control device for an internal combustion engine according to claim 1, wherein a transient response gain of the fuel injection amount with respect to the detected value is switched according to opening and closing of the drift control valve. 3. An intake pipe pressure downstream of the throttle valve is estimated based on an intake air flow rate detected by an air flow meter provided upstream of the throttle valve.
The fuel injection amount is calculated based on the estimated intake pipe pressure. In the estimation of the intake pipe pressure and / or the calculation of the fuel injection amount based on the intake pipe pressure, the fuel injection amount is calculated according to the opening and closing of the drift control valve. The fuel injection control device for an internal combustion engine according to claim 1, wherein the correction is performed. 4. The fuel injection control device for an internal combustion engine according to claim 3, wherein a transient response gain in estimating the intake pipe pressure is switched according to opening and closing of the drift control valve. 5. The fuel injection control device for an internal combustion engine according to claim 4, wherein a transient response gain when the drift control valve is closed is made smaller than a transient response gain when the valve is opened. 6. An intake pressure sensor for detecting an intake pipe pressure downstream of the throttle valve and upstream of the drift control valve, and calculates a fuel injection amount based on the intake pipe pressure detected by the intake pressure sensor. 2. The internal combustion engine according to claim 1, wherein in the calculation of the fuel injection amount based on the intake pipe pressure detected by the intake pressure sensor, a correction according to the opening and closing of the drift control valve is performed. 3. Fuel injection control device. 7. A calculation of a fuel injection amount based on the intake pipe pressure, wherein at least correction of a charging efficiency is performed, and the correction of the charging efficiency is individually set in accordance with opening and closing of the drift control valve. 7. The method according to claim 3, wherein
A fuel injection control device for an internal combustion engine according to claim 1. 8. The method according to claim 1, wherein the opening and closing of the drift control valve is determined based on whether an opening of the drift control valve is equal to or less than a reference opening. 3. The fuel injection control device for an internal combustion engine according to claim 1.