JPH10231757A - Evaporative fuel supply controller for lean burning internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaporative fuel supply controller for a lean burning internal combustion engine, which can suppress output fluctuation and can secure an appropriate fuel injection, therefore an appropriate combustion can be secured. SOLUTION: Fuel for driving an engine 1 which can perform lean burning is stored in a fuel tank 79, and evaporative fuel generated from the fuel tank 79 is stored in a canister 72. Evaporative fuel stored in the canister 72 is supplied to an intake duct 20 by being passed through a connecting pipe 71. An electronic control unit(ECU) 30 controls to increase the duty ratio of an evaporative fuel controlling solenoid valve 81 in the case that torque fluctuation is a little wider than target torque fluctuation. Also, in the case that the torque fluctuation is considerably wide, the ECU 30 decreases the corrective amount of an evaporative fuel amount and increases a fuel injection amount which ought to be ejected from a fuel injection valve 11. In this case, fuel injection timing is controlled to a phase advance side. While, in the case that the torque fluctuation is a little bit narrow, the corrective amount of the evaporative fuel amount is increased, and the fuel injection timing is controlled to a phase lag side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporative fuel supply control device for a lean burn internal combustion engine which supplies evaporative fuel (vapor) generated in a fuel tank or the like to an intake system in accordance with an operating state of the lean burn internal combustion engine. Things.

[0002]

2. Description of the Related Art In a conventionally used engine, fuel from a fuel injection valve is injected into an intake port, and a homogeneous mixture of fuel and air is supplied to a combustion chamber in advance. In such an engine, an intake passage is opened and closed by a throttle valve linked to an accelerator operation, and by this opening and closing, the amount of intake air supplied to a combustion chamber of the engine (consequently, a gas mixture in which fuel and air are homogeneously mixed). ) Is adjusted, thereby controlling the engine output.

[0003] However, in the technique based on the so-called homogeneous combustion described above, a large intake negative pressure is generated in accordance with the throttle operation of the throttle valve, and the pumping loss increases to lower the efficiency. On the other hand, by reducing the throttle of the throttle valve and supplying fuel directly to the combustion chamber, a combustible mixture is present near the ignition plug, and the air-fuel ratio of the portion is increased,
There is known a so-called "stratified combustion" technique for improving ignitability. In this technology, when the engine is under a low load, the injected fuel is unevenly supplied around the spark plug, and the throttle valve is opened almost fully to perform stratified combustion. Thereby, the pumping loss is reduced, and the fuel efficiency is improved.

[0004] An internal combustion engine capable of performing the above-mentioned "stratified combustion" has a combustion state such as stratified combustion, weak stratified combustion, homogeneous lean combustion, or homogeneous combustion when the load changes from a low load to a high load. Take sequentially.

[0005] When such "stratified combustion" is performed or when lean combustion is performed, a swirl may be formed in the mixture of the injected fuel. That is, a swirl control valve (SCV) is provided in the intake port, and the intensity of the swirl (swirl) is controlled by adjusting the opening of the SCV. As a result, the combustibility is improved with a small fuel supply amount.

An evaporative fuel supply control device is known which temporarily stores evaporative fuel (vapor) from a fuel tank or the like in a canister and supplies the stored vapor to an intake system according to the operation state of the internal combustion engine. (Japanese Unexamined Patent Publication No.
No. 77572, etc.).

In this technique, a purge control valve is provided in a purge passage for evaporative fuel that connects a canister for adsorbing evaporative fuel and an intake passage. The duty of the purge control valve is controlled so that an appropriate fuel purge amount (amount of vapor introduced into the intake passage; hereinafter, referred to as a purge amount) is obtained in accordance with the operating state of the engine.
Further, in this technique, an oxygen sensor is used to perform learning control to suppress a change in the air-fuel ratio. And
At the time of this learning, the correction of the fuel injection amount actually injected from the fuel injection valve is performed by the amount of the fuel purge amount.

[0008]

However, when the above technology is applied to an engine capable of performing lean combustion,
The following problems may occur. That is, in the lean burn region, it may be difficult to accurately detect the actual air-fuel ratio with the current oxygen sensor, and there may be no index for accurately controlling the fuel purge amount.

More specifically, an air-fuel ratio sensor such as an oxygen sensor is disposed in an exhaust passage of a conventional internal combustion engine, and an actual air-fuel ratio is detected based on an output signal of the sensor. The fuel injection amount and the like are feedback-controlled appropriately so that the target air-fuel ratio is calculated separately.
However, the oxygen sensor described above detects the air-fuel ratio when the air-fuel ratio (A / F) is close to, for example, stoichiometry. Air-fuel ratio and purge amount cannot be detected.

For this reason, in such a lean burn region, when controlling the supply amount of evaporated fuel, if the air-fuel ratio is not detected or if the detected air-fuel ratio is not accurate, the calculation of the purge amount is performed. The accuracy of is deteriorated. And if we performed control based on the inaccurate purge amount,
There has been a risk that the exhaust emission may be deteriorated, and that plug smoldering or misfire may occur.

In addition, when the purge amount is detected to be larger than the actual amount, the fuel injection amount is reduced by correction. In such a case, if the injection timing is constant, the ignition plug around the ignition plug is not ignited. There was a risk that the fuel would run out and cause a misfire.

The present invention has been made in view of the above circumstances, and has as its object to provide an evaporative fuel supply control device for a lean burn internal combustion engine capable of supplying evaporative fuel to the lean burn internal combustion engine. It is an object of the present invention to provide an evaporative fuel supply control device for a lean burn internal combustion engine that can suppress an unstable operation state, secure appropriate fuel injection, and thereby secure appropriate combustion.

[0013]

[Means for Solving the Problems]

(1) In order to achieve the above object, the features of the present invention are as follows:
In the evaporative fuel supply control device for a lean burn internal combustion engine, a purge passage for purging evaporative fuel generated from fuel storage means for storing fuel for the internal combustion engine into an intake system of the internal combustion engine, and introducing the fuel into the intake system from the purge passage. Purge control means for controlling the amount of evaporated fuel according to the operating state of the internal combustion engine; evaporative fuel correction means for correcting the amount of evaporated fuel based on the operating state of the internal combustion engine; Injection amount changing means for changing the fuel injection amount to the internal combustion engine based on the operation state after the change of the injection amount,
A modification control means for increasing / decreasing the amount of fuel vapor and controlling the fuel injection timing to a retard side or an advance side is provided.

Here, the operating state after changing the fuel injection amount can be exemplified by output fluctuations, but other elements indicating the operating state, such as the engine speed and the like, can be used without departing from the spirit of the present invention. Combustion pressure and the like can be used.

If the operating state is not stable after the fuel injection amount is changed by the injection amount changing means, for example, if the output fluctuation does not decrease, the correction control means reduces the fuel vapor amount and advances the injection timing. change.

When the operating condition is stabilized after the fuel injection amount is changed by the injection amount changing means, for example, when the output fluctuation is reduced, the correction control means increases the fuel vapor amount and sets the injection timing. Change the retard.

If the operating state becomes unstable after the fuel injection amount is changed by the injection amount changing means, for example, the output fluctuation becomes large, the amount of fuel vapor is reduced and the injection timing is changed to advance the injection timing. For example, the operation state can be stabilized.

Further, when the operating state is stabilized after the fuel injection amount is changed by the injection amount changing means, the amount of evaporated fuel can be increased because the operation state is stable, so that the vapor processing can be performed easily. At the same time, since the injection timing is retarded, stable combustion can be ensured.

(1-2) Reference value setting means for setting a stability determination criterion of the operating state in accordance with the engine speed, and fluctuation of the stability of the internal combustion engine from the reference value set by the reference value setting means. And a stability judging means for judging from the width.

In this way, the stability can be determined based on the fluctuation range from the reference value, and the amount of fuel vapor can be controlled according to the fluctuation range, so that the control is facilitated. In addition, at the time of high rotation or homogeneous combustion, the fluctuation range is small, and is smaller than the correction amount at the time of low rotation or stratified combustion (lean combustion). Therefore, erroneous correction of the fuel injection amount can be prevented.

(1-3) Further, the operating conditions are a change amount of the torque fluctuation (△ DLN) and a change of the torque fluctuation (△ TDLN) of the internal combustion engine. Correction means for correcting at least one of the fuel injection amounts can be provided. By this correction, rich misfire due to the purge can be more accurately prevented.

[0022]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an evaporative fuel supply control apparatus for a lean burn internal combustion engine according to the present invention. <First Embodiment> As shown in FIG.
A canister M3 for storing fuel vapor generated from fuel storage means M2 for storing the first fuel;
A purge passage M5 is provided for communicating the first intake system M4 with the canister M3.

Further, a purge control valve M6 for controlling the amount of evaporated fuel introduced into the intake system M4 is provided in the middle of the purge passage M5. Also,
An output fluctuation detecting means M7 for detecting an output fluctuation of the internal combustion engine M1 and a purge control valve controlling means M8 for controlling the purge control valve M6 in accordance with the detection result of the output fluctuation detecting means M7 are provided. I have.

Then, fuel injection means M9 for supplying fuel to the internal combustion engine M1 for performing lean combustion, and operation state detection means M10 for detecting the operation state of the internal combustion engine M1
And a fuel amount calculating unit M11 for calculating an amount of fuel supplied to the internal combustion engine M1 based on a detection result of the operating state detecting unit M10, and a calculation result of the fuel amount calculating unit M11. An injection amount calculation means M12 is provided for changing the fuel injection amount from the fuel injection means M9 to the internal combustion engine by correcting the amount of the evaporated fuel.

If the output fluctuation is not reduced by the fuel injection valve control means M13 for controlling the fuel injection means M9 based on the calculated fuel injection amount and the purge control valve control means M8, By reducing the correction amount for the evaporated fuel amount, the injection amount correction calculating unit M14 for correcting and calculating the fuel injection amount, and the correction amount for the evaporated fuel amount is reduced by the injection amount correction calculating unit M14. In this case, an injection timing control means M15 for controlling the fuel injection timing to the advanced side is provided.

Here, the purge control valve M6 and the purge control valve control means M8 constitute a purge control means for controlling the amount of fuel vapor in accordance with the detection results of the operating state detecting means M10 and the output fluctuation detecting means M7. I do.

The injection amount calculating means M12 includes an evaporated fuel correcting means and constitutes an injection amount changing means. Further, the injection amount correction calculation means M14 and the injection timing control means M15 constitute a correction control means.

In addition to these configurations, when the output fluctuation is lower than a predetermined value, the correction amount for the fuel injection amount is corrected by increasing the correction amount for the evaporated fuel amount. Means M21 and the injection amount correction calculating means M
If the correction amount of the evaporated fuel amount is increased by 21, an injection timing control means M22 for controlling the fuel injection timing to the retard side is provided. The injection amount correction calculation unit M21 and the injection timing control unit M22 constitute a correction control unit.

The injection amount correction calculating means M14 and the injection timing control means M15 and the injection amount correction calculating means M21 and the injection timing control means M22 may coexist or may be provided separately.

As shown in FIG. 1, the fuel of the internal combustion engine M1 is stored in the fuel storing means M2, and the fuel storing means M2
The fuel vapor generated from is stored in the canister M3.
The fuel vapor stored in the canister M3 is supplied to the purge passage M
5 to the intake system M4 of the internal combustion engine M1.
Here, by controlling the opening of the purge control valve M6 provided in the middle of the purge passage M5, the amount of evaporated fuel introduced into the intake system M4 is controlled. That is, the output fluctuation of the internal combustion engine M1 is detected by the output fluctuation detecting means M7, and according to the detection result, the purge control valve M6
Is controlled to open and close (duty control) by the purge control valve control means M8. At this time, when the amount of evaporated fuel introduced into the internal combustion engine M1 through the purge passage M5 and the intake system M4 increases, the total fuel amount to the internal combustion engine is increased, thereby suppressing the output fluctuation. Is achieved.

Further, fuel can be supplied to the internal combustion engine M1 by the fuel injection means M9 to perform lean combustion. Further, the operating state of the internal combustion engine M1 is detected by the operating state detecting means M10, and the total fuel amount introduced into the internal combustion engine M1 is calculated by the fuel amount calculating means MII based on the detection result. The fuel injection amount calculation means M12 calculates the fuel injection amount from the fuel injection means M9 by correcting the calculation result of the fuel amount calculation means M11 by the amount of the evaporated fuel. On the basis of the calculated fuel injection amount, the fuel injection valve control means M13 controls the fuel injection means M9.
Is controlled.

According to the present invention, when the output fluctuation is not reduced by the purge control valve control means M8, the correction amount for the evaporative fuel amount is reduced by the injection amount correction calculation means M14. The fuel injection amount is corrected and calculated. Therefore, the amount of fuel injected from the fuel injection means M9 substantially increases, and output fluctuations can be reliably suppressed. Further, when the correction amount for the evaporated fuel amount is reduced by the injection amount correction calculating means M14, the injection amount increases. However, if the ignition timing and the injection timing remain fixed, the ignition The amount of fuel around the spark plug at that time will be too large. On the other hand, in the present invention, the fuel injection timing is controlled to be advanced by the injection timing control means M15. For this reason, the amount of fuel around the ignition plug at the time of ignition can be maintained at an optimal value for combustion.

When the injection amount correction calculation means M21 and the injection timing control means M22 are provided in place of the injection amount correction calculation means M14 and the injection timing control means M15, the output fluctuation is controlled by the purge control valve control means M8. Is smaller than a predetermined value, the injection amount correction calculating unit M21 increases the correction amount for the fuel vapor amount,
The fuel injection amount is corrected and calculated. For this reason, the amount of fuel injected from the fuel injection means M9 is substantially reduced, and output fluctuations are kept to a minimum, and fuel efficiency can be improved.
When the correction amount for the evaporative fuel amount is reduced by the injection amount correction calculating means M21, the injection amount decreases. At this time, if the ignition timing and the injection timing remain fixed, the ignition The amount of fuel around the spark plug at that time will be too small. On the other hand, in the present invention, the fuel injection timing is controlled to the retard side by the injection timing control means M22. For this reason, the amount of fuel around the ignition plug at the time of ignition can be maintained at an optimal value for combustion.

Further, when the output fluctuation detected by the output fluctuation detecting means is higher than a predetermined value, the purge control valve control means controls the purge control valve to increase the supply amount of the evaporated fuel amount. Can be configured. Therefore, in this case, the fuel vapor increases, and the increase in the fuel vapor suppresses the output fluctuation. Further, when the output fluctuation is lower than a predetermined value, the purge control valve control means can be configured to control the purge control valve so as to reduce the supply amount of the evaporated fuel amount. Therefore, in this case, the amount of fuel vapor is reduced, and waste of fuel vapor is suppressed.

The term "predetermined value" may be different from each other.

FIG. 2 is a schematic configuration diagram showing a fuel vapor supply control device for a direct injection engine mounted on a vehicle in the present embodiment. Engine 1 as an internal combustion engine
For example, four cylinders 1a are provided, and the combustion chamber structure of each of the cylinders 1a is shown in FIG. As shown in these drawings, the engine 1 includes a piston in a cylinder block 2, and the piston reciprocates in the cylinder block 2. A cylinder head 4 is provided above the cylinder block 2, and a combustion chamber 5 is formed between the piston and the cylinder head 4. Further, in the present embodiment, four valves are arranged per cylinder la. In the figure, the first intake valve is denoted by reference numeral 6a, the second intake valve is denoted by 6b, the first intake port is denoted by 7a, the first intake port is denoted by 7a, and the first intake port is denoted by 7b. 2
An intake port, a pair of exhaust valves as 8, and a pair of exhaust ports as 9 are shown.

As shown in FIG. 3, the first intake port 7a
Is composed of a helical intake port, and the second intake port 7
b consists of a straight port extending almost straight.
In addition, an ignition plug 10 is disposed at the center of the inner wall surface of the cylinder head 4. Further, a fuel injection valve 11 as a fuel injection means is disposed around the inner wall surface of the cylinder head 4 near the first intake valve 6a and the second intake valve 6b. That is, in the present embodiment, the fuel from the fuel injection valve 11 is directly injected into the cylinder 1a.
The so-called stratified combustion (lean combustion) can also be performed in combination with the function of (17).

As shown in FIG. 2, the first intake port 7a and the second intake port 7b of each cylinder la are respectively connected via a first intake path 15a and a second intake path 15b formed in each intake manifold 15. Connected to the surge tank 16. A swirl control valve (SCV) 17 is arranged in each second intake passage 15b.
These SCVs 17 are connected to a step motor 19 via a common shaft 18. This step mode
An electronic control unit (hereinafter simply referred to as “ECU”)
) Is controlled based on an output signal from the control unit 30.

The surge tank 16 includes an intake duct 20
Is connected to the air cleaner 21 through the intake duct 20.
Inside, a throttle valve 23 which is opened and closed by a separate step motor 22 is provided. That is, the throttle valve 23 of this embodiment is of a so-called electronic control type, and basically, the step motor 22 is
The throttle valve 23 is opened and closed by being driven based on the output signal from 0. By opening and closing the throttle valve 23, the amount of intake air introduced into the combustion chamber 5 through the intake duct 20 is adjusted. In the present embodiment, the intake duct 20, the surge tank 16, the first intake path 15a and the second intake path 15
An intake passage as an intake system is constituted by b and the like. In the vicinity of the throttle valve 23, a throttle sensor 25 for detecting the opening (throttle opening TA) is provided.

An exhaust manifold 14 is connected to the exhaust port 9 of each of the cylinders, and the exhaust gas after combustion passes through the exhaust manifold 14 to a three-way catalyst, not shown, NOx.
The exhaust gas is purified by an exhaust gas purification catalyst composed of a purification catalyst and the like, and is discharged to an exhaust duct.

Further, in this embodiment, a known exhaust gas circulation (EGR) device 51 is provided. This EG
The R device 51 includes an EGR passage 5 as an exhaust gas circulation passage.
2 and an EGR valve 53 as an exhaust gas circulation valve provided in the middle of the passage 52. EGR passage 5
2 is an intake duct 20 downstream of the throttle valve 23;
It is provided to communicate with the exhaust duct. Further, the EGR valve 53 has a built-in valve seat, valve body, and step motor (all not shown), and these constitute an EGR mechanism. The opening degree of the EGR valve 53 fluctuates when the stepping motor intermittently displaces the valve body with respect to the valve seat. And the EGR valve 5
When the valve 3 opens, a part of the exhaust gas discharged to the exhaust duct flows to the EGR passage 52. The exhaust gas is
It flows to the intake duct 20 via the EGR valve 53. That is, a part of the exhaust gas is recirculated into the intake air-fuel mixture by the EGR device 51. At this time, the recirculation amount of the exhaust gas is adjusted by adjusting the opening degree of the EGR valve 53.

As shown in FIG. 2, the intake duct 20 is provided with a purge control device 72 for supplying evaporated fuel into the intake duct 20. This purge control device 7
Reference numeral 2 denotes a canister 74 having an activated carbon layer 73. An evaporative fuel chamber 75 and an air chamber 76 are formed in the canisters 74 on both sides of the activated carbon layer 73, respectively. The evaporative fuel chamber 75 is arranged in parallel and connected to a fuel tank 79 as fuel storage means via a pair of check valves 77 and 78 that can flow in opposite directions.

The fuel vapor chamber 75 and the throttle valve 23
A connection pipe 71 as a purge passage is connected between the downstream intake ducts 20, and the connection pipe 71 is connected to the check valve 80 and the first valve so as to be able to flow only from the fuel vapor chamber 75 into the intake duct 20. One solenoid valve 81 is provided.
The solenoid valve 81 is a control valve whose duty can be controlled by the ECU 30 described later, and constitutes a purge control valve. Note that the solenoid valve 81 may be a linear valve.

The air chamber 76 is communicated with the atmosphere through a check valve 82 that can only flow from the atmosphere to the air chamber 76 side.

When the supply of the fuel vapor to the intake duct 20 is to be stopped, the solenoid valve 81 is closed under the control of the ECU 30 described later. At this time, the fuel vapor generated in the fuel tank 79 is supplied to the fuel vapor chamber 75 through the check valve 78.
Then, the evaporated fuel is adsorbed on the activated carbon in the activated carbon layer 73. When the pressure in the fuel tank 79 decreases, the check valve 77 opens. Therefore, the check valve 77 prevents the fuel tank 79 from being deformed due to a decrease in the pressure in the fuel tank 79.

On the other hand, when the fuel vapor is to be supplied into the intake duct 20, the solenoid valve 81 is controlled to be opened by the ECU 30. Then, through the check valve 82, the air chamber 7
Air is discharged into 6 and the air is sent into the activated carbon layer 13. At this time, the fuel adsorbed on the activated carbon is released, and the air (fuel vapor) containing the fuel component flows out into the fuel vapor chamber 75. Next, the evaporated fuel is supplied into the intake duct 20 via the check valve 80 and the electromagnetic valve 81.

Now, as shown in FIGS.
The CU 30 is composed of a digital computer, and a RAM (random access memory) 32, a ROM (read only memory) 33, and a CPU (central processing unit) 134 composed of a microprocessor connected to each other via a bidirectional bus 31. , An input port 35 and an output port 36. In the present embodiment, the ECU 3
0, output fluctuation detection means, purge control valve control means,
A fuel amount calculating unit, an injection amount calculating unit, a fuel injection valve control unit, an injection amount correction calculating unit, and an injection timing control unit are configured.

The accelerator pedal 24 of the vehicle is connected to an accelerator sensor 26A that generates an output voltage proportional to the amount of depression of the accelerator pedal 24, and the accelerator sensor 26A detects the accelerator opening ACA. The output voltage of the accelerator sensor 26A is input to the input port 35 via the AD converter 37. Similarly, the accelerator pedal 24 has a fully-closed switch 26B for detecting that the depression amount of the accelerator pedal 24 is “0”.
Is provided. That is, the fully closed switch 26B
Generates a signal of “1” as the fully closed signal XIDL when the depression amount of the accelerator pedal 24 is “0”, and generates a signal of “0” otherwise. The output voltage of the fully closed switch 26B is also input to the input port 35.

The top dead center sensor 27 generates an output pulse when the first cylinder la reaches the intake top dead center, for example.
This output pulse is input to the input port 35. The crank angle sensor 28 has a crankshaft of 30 ° CA, for example.
An output pulse is generated each time the motor rotates, and this output pulse is input to the input port. In the CPU 34, the top dead center sensor 2
7 and the output pulse of the crank angle sensor 28, the engine speed NE is calculated (read).

Further, the rotation angle of the shaft 18 is
The swirl control valve sensor 29 detects the swirl control valve (SCV).
Seventeen opening degrees are detected. The output of the swirl control valve sensor 29 is input to an input port 35 via an A / D converter 37.

At the same time, the throttle sensor 25 detects the throttle opening degree TA. The output of the throttle sensor 25 is input to an input port 35 via an A / D converter 37.

In addition, in this embodiment, the intake pressure sensor 6 for detecting the pressure (intake pressure PM) in the surge tank 16
1 is provided. Further, a water temperature sensor 62 that detects the temperature of the cooling water of the engine 1 (cooling water temperature THW) is provided. The output of both sensors 61 and 62 is also A / D
The data is input to the input port 35 via the converter 37.

Further, a knock sensor 63 (see FIG. 4) for detecting knocking of the engine 1 is attached to the cylinder block 2 of the engine 1. The knock sensor 63 is a kind of vibration pickup. For example, the knock sensor 63 has a characteristic tuned so that the detection capability is maximized when the vibration generated by knocking matches the natural frequency of the detection element and resonates. have. The output of the knock sensor 63 is also input to the input port 35 via the A / D converter 37.
The ECU 30 has a gate signal generator,
The generator is opened based on a signal from the CPU 34.
A close signal is output to the input port 35. That is, the detection signal from knock sensor 63 is
It is input to the input port 35 by an open gate signal from the CPU 34, and is cut off by a close gate signal. Note that a torque sensor for detecting torque fluctuation or a combustion pressure sensor for detecting combustion pressure may be added.

On the other hand, the output ports 36 are connected to the respective fuel injection valves 11 and the respective step motors 1 via the corresponding drive circuits 38.
9, 22, the igniter 12, the EGR valve 53 (step motor) and the electromagnetic valve 81. And
The ECU 30 controls the fuel injection valve 11 and the step motors 19 and 2 based on signals from the sensors 25 to 29 and 61 to 63 according to a control program stored in the ROM 33.
2. The igniter 12, the EGR valve 53, the solenoid valve 81 and the like are suitably controlled.

The above sensors 25 to 29, 61 to 63
Constitutes operating state detecting means.

Next, a program related to various controls according to the present embodiment in the evaporative fuel supply control device for an engine having the above configuration will be described with reference to flowcharts.

First, a basic purge control program will be described with reference to the flowchart of FIG. First, the engine speed NE and the accelerator opening ACA are input (step 681). Next, a basic basic fuel injection amount (QALL) is interpolatively calculated according to the input data (step 682). In addition, as the injection amount map, a plurality of maps according to the operating conditions or the combustion state are prepared,
They are appropriately selected from among them.

At step 683, it is determined whether or not the purging is being performed. If the purging is being performed, the throttle opening TA and the engine speed NE are fetched (step 684). Next, an evaporative fuel amount correction amount (FPG) is calculated (step 685). This calculation is performed based on the correlation between the throttle opening TA engine speed NE previously stored in the ROM as a map and the evaporated fuel amount correction amount (FPG) (see FIG. 6). In the drawings, high, medium, and small are engine speeds. As the engine speed decreases, the amount of evaporated fuel correction increases.

If it is determined in step 683 that purging is not being performed, then in step 687, the fuel vapor amount correction amount is set to zero.
In steps 685 and 687, the fuel vapor amount correction amount (FPG)
Is determined, the routine proceeds to step 686, where the final fuel injection amount is determined. Here, the final fuel injection amount is determined by subtracting the evaporated fuel amount correction amount (FPG) from the basic fuel injection amount calculated in step 682, and then fuel injection is performed according to a separately determined fuel injection program.

As another method for calculating the fuel vapor correction amount (FPG), a method for obtaining from the purge gas amount Qp as shown in FIG. 7 and a method for obtaining from the pressure of the intake manifold as shown in FIG. Can be exemplified.

The routine shown in FIG. 5 is repeatedly executed at predetermined time intervals. Further, the purge control by the duty control is performed under a purge execution condition, for example, after completion of warming-up, that is, after a cooling water temperature has risen to a predetermined temperature or higher, and after a predetermined time, for example, 30 seconds, has elapsed after cranking has been completed. Holds, the duty ratio rises from the duty ratio 0 at the start of the purge, the magnitude of the duty ratio is controlled according to a predetermined control, and the duty ratio is set to 0 when a purge prohibition command, for example, a fuel cut execution command is input.

Such a correction routine, particularly step 6
Since the amount of fuel vapor correction is detected and corrected by 84 and 685, a large amount of fuel vapor can be processed without affecting drivability and emission.

The processing when the torque fluctuates during such control will be described with reference to the flowchart of FIG.

That is, FIG. 9 is a flowchart showing a "fuel supply control routine" for controlling the fuel injection amount, the injection timing, the purge amount, and the like by controlling the solenoid valve 81, the fuel injection valve 11, and the like in the present embodiment. Accordingly, this processing is executed instead of steps 684 to 686 in FIG. 5 and executed by the ECU 30 by interruption every predetermined crank angle.

When the processing shifts to this routine, the ECU
First, in step 101, an output fluctuation (torque fluctuation) DLN of the engine 1 is calculated based on output pulses from the top dead center sensor 27 and the crank angle sensor. The torque fluctuation DLN is an average value of each torque fluctuation generated in each cylinder la. Further, the torque T generated in each cylinder la for each combustion is:
It has the following equation.

T∝ (30 ° / tb) ^2- (30 ° / ta) ²

In the above equation, ta is a predetermined crank angle θ including the top dead center of the crankshaft of the engine 1.
It is the time required to pass through 1. Further, tb is a time required for the crankshaft to pass a predetermined crank angle θ2 advanced by 90 ° from the top dead center. Note that the crank angle component θ1 and the crank angle component θ2 have the same value, for example, 30 °, respectively.

Then, for example, the torque fluctuation DLN1 generated in a certain cylinder la is calculated by the difference of the torque T generated for each combustion in the cylinder la as shown in the following equation.

DLN1 = ｛(30 ° / t _bi ) ^2- (30 °
/ T _ai ) ² }-｛(30 ° / t _bi-1 ) ^2- (30 ° / t _ai-1 )
² }

Next, in step 102,
The torque fluctuation DLN calculated this time is the target torque fluctuation DL
It is determined whether it is larger (bad) than NLVL. Here, the target torque fluctuation DLNLVL is a value determined by the current basic fuel injection amount QALL (determined based on the engine speed NE and the accelerator opening ACA) and the engine speed NE in a separate routine. Yes (fixed values may be used). If the torque fluctuation DLN is larger than the target torque fluctuation DLNLVL, the process proceeds to step 103 on the assumption that the torque fluctuation DLN needs to be suppressed.

In step 103, this time, the torque fluctuation DLN is set to the target torque fluctuation DLNLVL by a predetermined value CL.
It is determined whether the value is larger than the value obtained by adding. And
When the torque fluctuation DLN is not larger than the value obtained by adding the predetermined value CL to the target torque fluctuation DLNLVL, the process proceeds to step 104 on the assumption that the torque fluctuation DLN is bad, but not so bad.
Α region).

In step 104, a value obtained by adding a predetermined value CP to the previous duty ratio DPG _i−1 is set as a duty ratio DPG for controlling a new solenoid valve 81. As a result, the amount of fuel vapor (purge amount) flowing to the engine 1 through the connection pipe 71 increases.

On the other hand, when the torque fluctuation DLN is larger than the value obtained by adding the predetermined value CL to the target torque fluctuation DLNLVL, it is determined that the degree of the torque fluctuation DLN is extremely bad, and the routine proceeds to step 105 (β region in FIG. 12). ).

In step 105, the fuel correction amount in the purge gas (the correction amount of the evaporated fuel amount) FPG
A value obtained by subtracting the predetermined value CF from _{i-1 is} set as a new fuel correction amount in purge gas (evaporation fuel amount correction amount) FPG.

If the torque fluctuation DLN is not larger than the target torque fluctuation DLNLVL in step 106, the process proceeds to step 106 on the assumption that the torque fluctuation DLN may increase slightly.

In step 106, it is determined whether or not the torque fluctuation DLN is smaller than a value obtained by subtracting a predetermined value CL from the target torque fluctuation DLNLVL. If the torque fluctuation DLN is not smaller than a value obtained by subtracting the predetermined value CL from the target torque fluctuation DLNLVL,
Assuming that the torque fluctuation DLN is extremely good,
7 (γ region in FIG. 12)

Then, in step 107, a value obtained by adding a predetermined value CF to the previous fuel vapor amount correction amount FPGi _{-1 is} set as a new fuel vapor amount correction amount FPG.

If the torque variation DLN is not smaller than the value obtained by subtracting the predetermined value CL from the target torque variation DLNLVL, the torque variation DLN is good, but the degree is not very good, and the process proceeds to step 108. The transition is made (δ region in FIG. 12).

In step 108, the value obtained by subtracting the predetermined value CP from the previous duty ratio DPG _{i−1 is} used as the duty ratio D for controlling the new solenoid valve 81.
Set as PG. As a result, the amount of fuel vapor (purge amount) flowing to the engine 1 through the connection pipe 71 decreases.

By the way, the above steps 104 and 10
5. Shift from step 107 and step 108,
In step 109, the basic fuel injection amount Q
Evaporated fuel amount correction amount FPG calculated this time from ALL
Is set as the final fuel injection amount QALLINJ to be injected from the fuel injection valve 11. Therefore, when the fuel vapor amount correction amount FPG is decreased in step 105, the final fuel injection amount QALLIN is substantially reduced.
J will increase. If the fuel vapor amount correction amount FPG is increased in step 107, the final fuel injection amount QALLINJ is substantially reduced.

In the following step 110,
An injection timing correction term AINJ (FPG) is calculated based on the currently calculated evaporated fuel amount correction amount FPG and the currently read engine speed NE. Here, when calculating the injection timing correction term AINJ (FPG), a map as shown in FIG. 11 is taken into consideration. That is, the higher the engine speed NE at that time and the larger the fuel vapor amount correction amount FPG, the more the injection timing correction term AI
NJ (FPG) is set to a large value.

Finally, at step 111, the basic injection timing AINJ calculated by a separate routine.
0, the injection timing correction term AINJ (FP
The value obtained by subtracting G) is set as the final fuel injection timing AINJ. Then, the subsequent processing ends once. Therefore, as the injection timing correction term AINJ (FPG) becomes smaller due to the decrease, the injection timing is corrected to the advance side, and as the injection timing correction term AINJ (FPG) becomes larger as the injection amount increases, the injection timing becomes more retarded. It will be corrected.

As described above, in the "fuel supply control routine", the solenoid valve 81, and hence the purge amount, are controlled in accordance with the output fluctuation at that time, and the final fuel injection amount QALLINJ and the fuel injection timing AINJ are determined. Controlled.

Next, the operation and effect of this embodiment will be described. (A) According to the above embodiment, when the torque fluctuation DLN is larger than the target torque fluctuation DLNLVL and not larger than a value obtained by adding the predetermined value CL to the target torque fluctuation DLNLVL (the α region in FIG. 12). ), Torque fluctuation D
Although LN is bad, it is judged that the degree is not extremely bad. In this case, the duty ratio DP
G is controlled to increase, and the purge amount increases. Here, FIG.
As shown by 0, it is known that the torque fluctuation DLN decreases as the total fuel amount increases. As the purge amount increases as described above, the total fuel amount basically increases. Therefore, the torque fluctuation DLN can be suppressed by such control.

(B) Also, as described above, the duty ratio D
Even if the PG is increased and the purge amount is increased, the torque fluctuation DLN
May not be small but rather large. In such a case (that is, the torque variation DLN is equal to the target torque variation D
If it is larger than the value obtained by adding the predetermined value CL to LNLVL), it is determined that the degree of the torque fluctuation DLN is extremely bad. Then, in this case, the evaporated fuel amount correction amount FPG is reduced, and therefore, the final fuel injection amount QALLINJ to be injected from the fuel injection valve 11 is increased. As a result, even if fuel does not exist in the purge gas, it is possible to reliably suppress the torque fluctuation DLN by increasing the amount of fuel directly injected in this way.

(C) Further, in this case, the final fuel injection amount QALLINJ increases, but at this time, if the ignition timing and the injection timing remain fixed, the fuel amount around the ignition plug 10 at the time of ignition is too large. Will be. On the other hand, in the present embodiment, when the final fuel injection amount QALLINJ increases as described above, the fuel injection timing AI
NJ is controlled to the advance side. For this reason, the amount of fuel around the ignition plug 10 at the time of ignition can be maintained at an optimal value for combustion. As a result, good combustion can be ensured.

The advance angle at this time, that is,
The absolute value of the injection timing correction term AINJ (FPG) is made variable according to the fuel vapor amount correction amount FPG. For this reason, the fuel amount around the ignition plug 10 can be secured in accordance with the degree of increase in the final fuel injection amount QALLINJ, and the above-described operation and effect can be further ensured.

(D) In addition, in the present embodiment, when the torque fluctuation DLN is smaller than a value obtained by subtracting the predetermined value CL from the target torque fluctuation DLNLVL, even if the torque fluctuation DLN increases to some extent. It is determined that there is no problem (γ region in FIG. 12). In this case, the duty ratio DPG is controlled to decrease, and the purge amount decreases.
For this reason, although the torque fluctuation DLN is slightly worse than before, the waste of the evaporated fuel can be suppressed.

(E) In addition, in the present embodiment, when the torque fluctuation DLN is not larger than the target torque fluctuation DLNLVL and is not smaller than a value obtained by subtracting a predetermined value CL from the target torque fluctuation DLNLVL. , The fuel vapor correction amount FPG is increased, so that the fuel injection valve 11
The final fuel injection amount QALLINJ to be injected from the engine is reduced. Therefore, the fuel consumption can be reliably improved by reducing the amount of fuel directly injected.

(F) Further, as shown in FIG. 13, in this case, the final fuel injection amount QALLINJ decreases, but at this time, if the ignition timing and the injection timing remain fixed, the ignition time (ignition point) Is too small (solid line in the figure). On the other hand, in the present embodiment, when the final fuel injection amount QALLINJ decreases as described above, the fuel injection timing AI
NJ is controlled to the retard side. For this reason, the amount of fuel around the ignition plug 10 at the time of ignition can be maintained at an optimal value for combustion. As a result, good combustion can be ensured.

The degree of retardation at this time, that is,
The absolute value of the injection timing correction term AINJ (FPG) is made variable according to the fuel vapor amount correction amount FPG. For this reason, the fuel amount around the ignition plug 10 can be kept in accordance with the degree of the decrease in the final fuel injection amount QALLINJ, and the above-described operation and effect can be further ensured.

(G) In addition, in the tree embodiment, even in the homogeneous combustion state, even if a conventional oxygen sensor or the like is not used,
The fuel vapor amount correction amount FPG can be properly calculated. As a result, fuel supply control can be appropriately performed without an oxygen sensor or the like.

The steps 104, 105, 10 in FIG.
The predetermined values CP and CF of 7, 108 may be values determined in accordance with the operating state or combustion state of the engine.
For example, the value is increased for homogeneous combustion, and is decreased for stratified combustion. Thereby, controllability can be improved and combustion can be stabilized.

<Second Embodiment> Next, a second embodiment will be described with reference to FIGS. In this example, the purge gas amount Qp or the evaporated fuel amount correction amount FPG is controlled according to the torque fluctuation. First, the engine speed NE and the accelerator opening ACA are input (step 4).
001). Next, a basic basic fuel injection amount (QALL) is interpolatively calculated according to the input data (step 4).
002). This is similar to step 682 in FIG. 5 described above.

In step 4003, it is determined whether or not purging is being performed.
Then, the torque fluctuation DLN and the evaporated fuel amount correction amount FPG are input. The torque fluctuation is obtained by the torque fluctuation detecting means by quantifying the difference between the old torque before a predetermined time and the current torque. The evaporated fuel amount correction amount FPG is calculated by the same method as in step 685 in FIG.

Next, at step 4005, the correction amount of the evaporated fuel amount correction amount FPG in accordance with the torque fluctuation, ie, the correction amount ΔFPGH
Is calculated. Correction amount of evaporated fuel amount correction amount FPG △ FPG
For the calculation of H, the map of FIG. FIG.
In the map of 5 (1), the magnitude of the torque fluctuation is plotted on the horizontal axis,
Evaporated fuel amount correction amount FPG corresponding to the magnitude of torque fluctuation
The correlation between the two is determined with the correction amount ΔFPGH of the vertical axis as the vertical axis.

In step 4005, a purge gas correction amount △ Qprg according to the torque fluctuation is calculated. The calculation of the purge gas correction amount △ Qprg refers to the map of FIG. The map of FIG. 15 (2) defines the correlation between the torque fluctuation magnitude on the horizontal axis and the purge gas correction amount △ Qprg corresponding to the torque fluctuation magnitude on the vertical axis.

Then, in step 4006, step 4
The correction amount of the evaporated fuel amount correction amount FPG obtained in 005 △ FPG
H is a correction amount FPGH of the previously obtained evaporated fuel amount correction amount FPG.
And the correction amount FP of the new evaporated fuel amount correction amount FPG
Get GH.

Next, at step 4007, the correction amount FPGH of the new correction amount FPG of the fuel vapor amount is added to the correction amount FPG of the fuel vapor amount previously obtained, and the correction amount FPG of the new fuel amount is calculated.
Get PG.

Further, in step 4008, the purge gas correction amount △ Qpr is added to the previous purge gas fluctuation amount (△ Qp).
g is added to make a new purge gas fluctuation amount (△ Qp).
Then, △ Qp obtained in step 4008 is added to the previous purge gas amount Qp to obtain a corrected purge gas amount Qp (step 4009). Note that the previous purge gas amount Qp
Is the Qp obtained in advance or the Qp obtained in the previous execution of the routine.

If it is determined in step 4003 that purging is not being performed, the fuel vapor amount correction amount FPG is set to 0 (step 4010), and the purge gas amount Qp is set to 0 (step 4011).

In step 4012, step 400
The degree of opening of the purge control valve is controlled based on the value of the purge gas amount Qp obtained in steps 9 and 4011. Although this control is not shown,
This is performed with reference to a map that defines a correlation between the purge gas amount Qp and the opening degree V (Qp) of the purge control valve. This map is stored in the ROM in advance. As the opening of the purge control valve increases, the purge gas amount Qp increases almost in proportion.

Next, at step 4013, the final fuel injection amount is determined. Here, step 4002
From the basic fuel injection amount calculated in the above, the fuel vapor amount correction amount (F
PG) is determined to determine the final fuel injection amount.

Further, the following steps 4014, 4015
Then, injection timing control is performed. The content of this step is the same as the processing of steps 110 and 111 shown in FIG. That is, in step 4014, the injection timing correction term AINJ (FPG) is calculated based on the currently calculated evaporated fuel amount correction amount FPG and the currently read engine speed NE. Here, when calculating the injection timing correction term AINJ (FPG), FIG.
The map shown in FIG. That is, the higher the engine speed NE at that time and the larger the fuel vapor amount correction amount FPG, the higher the injection timing correction term AINJ.
(FPG) is set to a large value.

Finally, at step 4015, the basic injection timing AINJ calculated by a separate routine.
0, the injection timing correction term AINJ (FP
The value obtained by subtracting G) is set as the final fuel injection timing AINJ. Then, the subsequent processing ends once. Therefore, as the injection timing correction term AINJ (FPG) becomes smaller due to the decrease, the injection timing is corrected to the advance side, and as the injection timing correction term AINJ (FPG) becomes larger as the injection amount increases, the injection timing becomes more retarded. It will be corrected.

<Third Embodiment> A third embodiment will be described with reference to FIGS. In the third embodiment, the purge amount and the evaporated fuel amount correction amount FPG are corrected based on the output fluctuation and the change in the output fluctuation in the second embodiment.

This is done by referring to the amount of change in torque fluctuation (△ DLN) and the change in torque fluctuation (△ TDLN) of the internal combustion engine as the above-mentioned operating state. This is an example in which a correction unit that corrects at least one of the amounts is provided. In this embodiment, the fluctuation amount of the torque fluctuation (△ DLN) is the difference between the current torque fluctuation and the target torque fluctuation DLN0, and the torque fluctuation change (△ TDLN) is the current torque fluctuation and the previous torque fluctuation. Is the difference.

[0108] Such a correction means comprises a program, and is realized on the CPU by executing the program. As shown in FIG. 16, first, the engine speed NE and the accelerator opening A
The CA is input (step 4101). Next, a basic fuel injection amount (QALL) is calculated in an interpolative manner according to the input data (step 4102). This is similar to step 682 in FIG. 5 described above.

In step 4103, the torque fluctuation DL
N, the fuel vapor amount correction amount FPG is input. The torque fluctuation is obtained by the torque fluctuation detecting means quantifying the difference between the torque before a predetermined time and the current torque. The evaporated fuel amount correction amount FPG is calculated by the same method as in step 685 in FIG.

In step 4104, it is determined whether or not purging is in progress. If purging is in progress, step 4105 is performed.
Then, the target torque fluctuation DLN0 is subtracted from the torque fluctuation DLN to calculate a fluctuation amount ΔDLN of the torque fluctuation. Next, at step 4106, the current DLN to the previous DLNO
Is subtracted to calculate the torque fluctuation change ΔTDLN. After each variation is calculated, the current torque variation DLN is replaced with the previous torque variation (step 4107). FIG. 17 shows す る と DLN and △ TDLN. In FIG. 17, the vertical axis represents the torque fluctuation, and the horizontal axis represents the air-fuel ratio A / F.

Next, at step 4108, from the map of FIG. 18, the fluctuation amount of the torque fluctuation obtained at step 4105 {DLN and the torque fluctuation change obtained at step 4106}
Referring to the TDLN, a correction amount △ FPGH of the evaporated fuel amount correction amount FPG and a purge gas fluctuation amount △ Qp are calculated.
The map in FIG. 18 shows the correlation between the correction amount △ FPGH of the evaporated fuel amount correction amount FPG and the purge gas fluctuation amount △ Qp, with the fluctuation amount of the torque fluctuation △ DLN on the horizontal axis and the torque fluctuation change △ TDLN on the vertical axis. Is defined.

The meaning of FIG. 18 will be described in detail. In general, in an internal combustion engine, as shown in FIG. 19, when the output fluctuation with respect to the air-fuel ratio becomes too lean, the combustion exceeds the combustion limit, the combustion becomes unstable, and the torque fluctuation increases.
Also, if it becomes too rich, it will exceed the combustion limit,
Since a fire does not occur, torque fluctuations increase.

The width of the air-fuel ratio in a lean-burn internal combustion engine, particularly an in-cylinder injection type internal combustion engine, is indicated by an arrow in FIG. 19. In the case of a lean-burn internal combustion engine, especially an in-cylinder injection, the air-fuel ratio exceeds the combustion limit. And the torque fluctuation may increase. The following can be understood from the magnitudes of $ DLN and $ TDLN.

ΔDLN> 0: The air-fuel ratio is leaner than the target ΔDLN <0: The air-fuel ratio is richer than the target ΔTDLN> 0: Indicates that the air-fuel ratio has changed to the lean side from the previous time ΔTDLN < 0: Indicates that the air-fuel ratio has changed to the rich side from the previous time

Here, the reason that "△ DLN> 0: the air-fuel ratio is leaner than the target" is that 1-FPG is too large, the fuel injection amount is insufficient, and 1-purge amount Q
p is too small and the evaporative fuel in the actual purge gas is FP
That is, it is insufficient than the value of G.

In the case of 1-, the FPG is reduced, and in the case of 1-, the air-fuel ratio can be made closer to the target by increasing the purge amount Qp. Also, "@DLN
<0: The air-fuel ratio is richer than the target ”because the 2-FPG is too small and the fuel injection amount is too large, the 2-purge amount Qp is large, and the actual evaporation fuel in the purge gas is less than the FPG. It is over the value.

In the case of 2-, the FPG is increased, and in the case of 2-, the air-fuel ratio can be made closer to the target by reducing the purge amount Qp.

The purge gas concentration, the purge amount, and the combustion state can be estimated from the combination of the above ΔDLN and ΔTDLN, and can be corrected.

(FIG. 18, area: $ DLN> 0, $ TD
(LN> 0) In FIG. 18, if the current output fluctuation is larger than the target torque fluctuation (ie, ΔDLN is positive) and the output fluctuation is larger than the previous time (ie, ΔTDLN is positive), FIG. Area. In this region, the air-fuel ratio is lean, and the fuel amount in the cylinder is increasing so as to be leaner. The reason why the air-fuel ratio is lean is 1- or 1-. However, since lean is in progress, it is estimated that the in-cylinder fuel cannot be increased even if the purge gas concentration is low and the purge amount Qp is increased. You. Therefore, the fuel vapor amount correction amount FPG is reduced, and the combustion injection amount is increased.

(FIG. 18, area: $ DLN> 0, $ TD
LN <0) When the present output fluctuation is larger than the target torque fluctuation (ie, ΔDLN is positive) and the output fluctuation is smaller than the previous fluctuation (ie, ΔTDLN is negative),
This corresponds to the area in FIG. In this region, the air-fuel ratio is leaner than the target, but the fuel amount in the cylinder is corrected so as to approach the target from the previous time. In other words, the purge gas concentration is not low, and if the purge amount is increased,
It is estimated that evaporative fuel can be supplied into the cylinder. Therefore,
In order to increase the purge amount, the in-cylinder fuel is corrected by increasing Qp instead of decreasing FPG.

(FIG. 18, area: $ DLN <0, $ TD
LN <0) When the current output fluctuation is smaller than the target torque fluctuation (that is, ΔDLN is negative) and the output fluctuation is smaller than the previous fluctuation (that is, ΔTDLN is negative),
This corresponds to the area in FIG. In this region, the air-fuel ratio is richer than the target, and the fuel amount in the cylinder is richer than the previous time. In other words, the concentration of the purge gas is very high (the vapor from the combustion tank gradually increases), and it is estimated that the concentration further increases. Therefore, the fuel vapor amount correction amount FPG is increased, and the fuel injection amount is reduced.

(FIG. 18, area: $ DLN <0, $ TD
LN> 0) When the current output fluctuation is smaller than the target torque fluctuation (that is, ΔDLN is negative) and the output fluctuation is larger than the previous fluctuation (that is, ΔTDLN is positive),
This corresponds to the area in FIG. In this region, the air-fuel ratio is richer than the target, but the torque fluctuation is increased from the previous time. In other words, the purge gas concentration is very high,
Although the fuel injection amount is reduced, the combustion becomes unstable. Therefore, the purge gas amount Qp is reduced to prevent combustion deterioration.

In FIG. 18, Cpp: an amount to increase the purge amount Cpm: an amount to decrease the purge amount Cfp: an amount to increase the estimated concentration value in the purge gas Cfm: an amount to decrease the estimated concentration value in the purge gas .

Next, at step 4109, the correction amount ΔF of the evaporated fuel amount correction amount FPG obtained at step 4108.
The correction amount FP of the evaporated fuel amount correction amount FPG obtained last time from PGH
In addition to the GH, a new correction amount FPGH of the evaporated fuel amount correction amount FPG is calculated.

In step 4110, step 4109
Correction amount of the new fuel vapor correction amount FPG obtained in step △ FPG
H is added to the previous evaporated fuel amount correction amount FPG to obtain a new evaporated fuel amount correction amount FPG.

In step 4111, step 4
The purge gas fluctuation amount ΔQp obtained in step 108 is added to the previous purge gas fluctuation amount ΔQp, and a new purge gas fluctuation amount ΔQp
And Then, in step 4112, the new purge gas fluctuation amount ΔQp is added to the previous purge gas amount Qp to obtain a corrected new purge gas amount Qp.

If it is determined in step 4104 that purging is not being performed, the current DLN is set to the previous DLN (step 4113), the evaporated fuel amount correction amount FPG is set to 0 (step 4114), and the purge gas amount Qp is set to 0. (Step 4115).

In step 4116, step 411 is executed.
The opening degree of the purge control valve is controlled based on the value of the purge gas amount Qp obtained in 2,4115. This control is performed in the same manner as in the second embodiment described above with reference to a map that defines a correlation between the purge gas amount Qp and the opening degree V (Qp) of the purge control valve.

Next, at step 4117, the final fuel injection amount is determined. Here, step 4102
From the basic fuel injection amount calculated in the above, the fuel vapor amount correction amount (F
PG) is determined to determine the final fuel injection amount.

Note that the subsequent injection timing control is the same as in the above-described embodiment, and a description thereof will be omitted.

<Other Examples> The above embodiment is not limited to the above, but may be modified as follows.

(1) In the above embodiment, the control as shown in FIG. 12 is performed according to the value of the torque fluctuation DLNVL with respect to the target torque fluctuation DLNLVL. Good. For example, the control may be further divided into multiple sections, or the control contents of the γ region and the δ region may be reversed.

(2) In the above embodiment, the present invention is embodied in the in-cylinder injection type engine 1. However, the present invention is embodied in a so-called general stratified combustion or weak stratified combustion type. You may. For example, the intake ports 7a, 7b
And the intake port type that injects toward the back side of the umbrella portion of the intake valves 6a and 6b. Although a fuel injection valve is provided on the intake valves 6a and 6b side, a type in which fuel is injected directly into the cylinder bore (combustion chamber 5) is also included. Further, the present invention can be embodied in an engine having an SCV 17 capable of performing lean burn.

Therefore, in this specification, the lean burn means
It is a meaning including these meanings. (3) In the above embodiment, the present invention is embodied in the case of the gasoline engine 1 as the internal combustion engine. However, the present invention can be embodied in the case of a diesel engine or the like.

(4) In addition, the ignition timing may be changed in addition to the fuel injection timing.

From the above embodiment, it can be said that (a) the degree to which the fuel injection timing is advanced or retarded by the injection timing control means may be determined according to the correction amount for the evaporated fuel amount. . With such a configuration, more optimal combustion can be ensured at the time of ignition. The torque fluctuation in the above embodiment may be obtained directly from the torque sensor, or may be indirectly estimated from a change in the number of revolutions and a change in the combustion pressure.

[0137]

As described in detail above, according to the present invention,
In the evaporative fuel supply control device for the lean burn internal combustion engine capable of supplying the evaporative fuel to the lean burn internal combustion engine, it is possible to suppress the output fluctuation and secure the appropriate fuel injection,
Thus, an excellent effect that proper combustion can be ensured is achieved.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram of the invention according to claims 1 and 2.

FIG. 2 is a schematic configuration diagram showing an evaporative fuel supply control device for an engine according to one embodiment.

FIG. 3 is an enlarged sectional view showing a cylinder portion of the engine.

FIG. 4 is an electric block circuit diagram schematically showing an ECU.

FIG. 5 is a flowchart illustrating an example of a correction control of an evaporated fuel amount.

FIG. 6 shows a throttle opening TA and a fuel vapor amount correction amount FPG.
4 is a map that defines a correlation between the engine speed and the engine speed NA.

FIG. 7 is a map that defines a relationship between an evaporated fuel amount correction amount FPG and a purge gas amount Qp.

FIG. 8 is a map that defines a correlation between an evaporated fuel amount correction amount FPG and a differential pressure between atmospheric pressure and intake manifold pressure.

FIG. 9 is a flowchart showing a “fuel supply control routine” executed by the ECU.

FIG. 10 is a graph showing a relationship between torque fluctuation and total fuel increase.

FIG. 11 is a map showing a relationship of an injection timing correction term to an evaporation fuel amount correction amount.

FIG. 12 is a chart showing control contents set according to a value of a torque variation with respect to a target torque variation.

FIG. 13 is a schematic diagram showing the behavior of fuel around the ignition plug and the relationship between the amount of fuel when swirling is poor on the line FF ′, and the like.

FIG. 14 is a flowchart of the second embodiment.

FIG. 15 shows (1) the relationship between DLN and △ Qprg,
(2) is a map in which the relationship between the DLN and the fuel vapor amount correction amount △ FPRFGH is defined.

FIG. 16 is a flowchart of the third embodiment.

FIG. 17 is a map that defines the relationship between torque fluctuation, air-fuel ratio A / F, and target torque fluctuation.

FIG. 18 △ DLN, △ TDLN, △ Qp, △ FPG
5 is a map that defines the relationship with H.

FIG. 19 is a graph showing a relationship between a torque fluctuation and an air-fuel ratio.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine as an internal combustion engine 11 ... Fuel injection valve as fuel injection means 20 ... Intake duct 23 which constitutes an intake system 23 ... Throttle valve 25 ... Throttle sensor 26A which constitutes operating state detecting means 26A ... It constitutes operating state detecting means Accelerator sensor 26B Fully-closed switch forming operating state detecting means 27 Top dead center sensor forming operating state detecting means 28 Crank angle sensor forming operating state detecting means 29 Swirl control forming operating state detecting means Valve sensor 30: ECU that constitutes output fluctuation detection means, purge control valve control means, total fuel amount calculation means, injection amount calculation means, fuel injection valve control means, injection amount correction calculation means, and injection timing control means 61: Operating state Intake pressure sensor 62 constituting detecting means ... Water temperature sensor 63 constituting operating state detecting means 63 Knock sensor 71 constituting operating state detecting means 71 Connection pipe as purge passage 72 Purge control device 73 Activated carbon layer 74 Canister 79 Fuel tank 81 as fuel storage means 81 First electromagnetic member constituting purge control valve valve

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI F02D 41/34 F02D 41/34 E 43/00 301 43/00 301H 301J 45/00 330 45/00 330 (72) Inventor Mashiki Zenichiro 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (5)

[Claims] A purge passage for purging evaporative fuel generated from fuel storage means for storing fuel of the internal combustion engine into an intake system of the internal combustion engine; and an evaporative fuel amount introduced from the purge passage into the intake system. Purge control means for controlling in accordance with the operating state of the internal combustion engine; evaporative fuel correcting means for correcting the amount of evaporated fuel based on the operating state of the internal combustion engine; and fuel to the internal combustion engine based on the corrected amount of evaporated fuel. Injection amount changing means for changing the injection amount, correction control means for controlling the fuel injection timing to the retard side or the advance side while increasing or decreasing the evaporated fuel amount according to the operating state after the injection amount is changed, An evaporative fuel supply control device for a lean burn internal combustion engine, comprising: 2. The correction control device according to claim 1, wherein when the operating state after the change in the injection amount is not stable, the correction control means reduces the fuel vapor amount and controls the fuel injection timing to the advanced side. An evaporative fuel supply control device for a lean-burn internal combustion engine according to claim 1. 3. The correction control unit according to claim 1, wherein when the operation state after the change in the injection amount is stabilized, the amount of the evaporated fuel is increased and the fuel injection timing is controlled to the retard side. An evaporative fuel supply control device for a lean-burn internal combustion engine according to claim 1. 4. A reference value setting means for setting a stability determination criterion for an operating state in accordance with an engine speed, and a stability for determining the stability of the internal combustion engine by a variation range from the reference value set by the reference value setting means. 2. The evaporative fuel supply control apparatus for a lean burn internal combustion engine according to claim 1, further comprising: degree determination means. 5. The operating state includes a change amount (ΔDLN) of a torque fluctuation of the internal combustion engine and a torque fluctuation change (ΔTDLN) of the internal combustion engine.
3. A fuel vapor supply control for a lean burn internal combustion engine according to claim 1, further comprising a correcting means for correcting at least one of an evaporated fuel amount and a fuel injection amount from the torque fluctuation and the torque fluctuation change. apparatus.