JPH1136964A - Fuel injection control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the contorl accuracy of fuel injection amount from the starting time, by correcting the fuel injection amount to make the detected engine speed agreed with a target constant engine speed, when the fuel injection amount is set, and the fuel is injected form a fuel injection nozzle of each cylinder in an idling operation. SOLUTION: A controller 18 inputs the signals from a nozzle lift sensor 12, a fuel temperature sensor 15, a cooling water temperature sensor 13, an accelerator opening sensor 16, an engine speed sensor 14 for detecting the pump engine speed, or the like, and computes and outputs a contorl signal for the fuel injection amount and injection period on the basis of these signals. On this occasion, the basic fuel injection amount is computed, and then the maximum injection amount is limited to this fuel injection amount. Then whether the error of the fuel injection amount is learned or not is judged for permission, and the error of the fuel injection amount is computed when the learning is permitted. Whereby the injection amount for correction is computed on the basis of the fuel injection amount of which the maximum injection amount is restricted, and the error of the injection amount, and is output as a contorl signal of a fuel injection pump 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for controlling various control parameters by using a fuel injection amount of an internal combustion engine as a control signal.

[0002]

2. Description of the Related Art In a diesel engine or the like, a basic fuel injection amount is determined according to the load and the number of revolutions of the engine, and a fuel injection pump is electronically controlled so as to attain the target injection amount. Is done.

However, the amount of fuel actually injected may not exactly coincide with the target injection amount due to variations in production of the fuel injection pump and the fuel injection nozzle and deterioration with time. In this case, the optimum fuel supply characteristic does not become the optimum fuel supply characteristic according to the operation state. For example, if the actual injection amount is larger than the target injection amount, the smoke generation amount increases in a high load region or the like,
On the other hand, if the amount is small, sufficient engine output cannot be secured.

[0004] Further, if fuel cut and recovery during deceleration or the like are controlled in accordance with the injection amount, the timing will vary and the exhaust gas composition will deteriorate.

Conventionally, for example, Japanese Patent Application Laid-Open No. 63-2309
As disclosed in Japanese Patent Publication No. 44-44, EG of diesel engine
In controlling the R amount (exhaust gas recirculation amount) in accordance with the operation state, if the EGR amount is controlled using the target injection amount as a control signal, if there is an error between the actual injection amount and the actual combustion amount, the actual combustion is not performed. On the other hand, excessive exhaust gas recirculation is performed, and smoke may increase. Therefore, according to this publication, in order to grasp the error of the fuel injection amount, for example, a correction amount of the fuel injection amount necessary to maintain a target predetermined rotational speed during idling operation or the like is calculated, and the correction amount is calculated. The target injection amount is corrected based on the amount, and the EGR amount is controlled based on the corrected target injection amount.

In this way, even if the fuel injection pump has variations in characteristics, etc., the target injection amount and the actual injection amount correspond to each other, so that the exhaust gas composition at the time of exhaust gas recirculation becomes worse than the target value. Problems can be avoided.

[0007]

However, since the fuel injection amount is not corrected by the learning value at the time of the previous operation at the time of starting in the above-mentioned conventional system, the variation of the injection amount is large as shown in FIG. However, there is a possibility that the actual injection amount becomes excessive and a large amount of smoke is generated, or the injection amount is insufficient and the engine cannot be started.

The present invention has been proposed to solve such a problem, and an object of the present invention is to improve the control accuracy of the fuel injection amount from the start of a fuel injection control device for an internal combustion engine.

[0009]

According to a first aspect of the present invention, there is provided means for detecting an engine operating state, means for calculating a basic fuel injection amount based on the engine operating state, and means for determining an idle state of the engine. Means for correcting the idle fuel injection amount so that the engine speed becomes the target speed in the idle state; and means for determining whether to permit learning of the fuel injection amount error when a predetermined condition is satisfied in the idle state.
Means for calculating and learning the injection amount error from the idle fuel injection amount corrected when the learning is permitted; means for storing the injection amount error learned during the previous operation even after the operation is stopped; Injection amount correcting means for correcting the basic fuel injection amount based on the learned injection amount error to obtain a target injection amount.

A second aspect of the present invention includes means for setting a learning value reflection gain at the time of starting, wherein the injection amount correction means adds the learning value reflection gain at the time of starting to the injection amount error learned during the previous operation. Is added to the basic fuel injection amount to obtain the target injection amount.

According to a third aspect of the present invention, there is provided a means for setting a learning value reflection gain at the time of starting, wherein the injection amount correcting means is provided with an injection amount learned during a previous operation during a predetermined time from the start. The target injection amount is obtained by adding a value obtained by multiplying the amount error by a learning value reflection gain at the time of starting to the basic fuel injection amount.

According to a fourth aspect of the present invention, the learning value reflection gain setting means sets the learning value reflection gain at the start according to the sign of the injection amount error learned during the previous operation.

According to a fifth aspect of the present invention, the learning value reflection gain setting means sets the learning value reflection gain at the time of starting to be smaller as the fuel temperature increases.

According to a sixth aspect of the present invention, there is provided a means for detecting various parameters in an idle state, wherein the actual equivalent injection amount calculating means maintains a target rotational speed in the idle state in accordance with the detected various parameters. It is assumed that an actual equivalent injection amount corresponding to the required fuel injection amount is calculated.

[0015]

According to the first aspect of the invention, in the idling operation state, a basic fuel injection amount is set, and the fuel is pumped from the fuel injection pump to the fuel injection nozzle of each cylinder and injected. At this time, in order to keep the idle speed constant, the engine speed is detected, and the fuel injection amount is corrected so that the detected speed matches the target constant speed.

Under these idle conditions, an error in the injection amount is calculated based on the deviation between the fuel injection amount corrected to maintain the actual idle speed constant and the actual equivalent injection amount.

In general, the error in the injection amount is caused by various causes such as variations in production of the engine, the fuel injection pump and the fuel injection nozzle, and deterioration over time.

Accordingly, when the injection amount error is obtained in this manner and the target injection amount is calculated from the error and the basic injection amount, the target injection amount accurately matches the actual injection amount. If the fuel injection amount is controlled based on the amount, an optimum fuel injection amount can be obtained according to the operating state of the engine.

As a result, an increase in smoke and particulates due to an error in the fuel injection amount is prevented, and the drivability during recovery after the fuel cut is improved.

By the way, in the conventional system, since the fuel injection amount is not corrected by the learning value at the time of the previous operation at the time of starting, the variation of the injection amount is large, the actual injection amount becomes excessive, and a large amount of smoke is generated. There is a possibility that starting may not be possible due to generation of an insufficient amount of injection.

According to the present invention, in response to this, the fuel injection amount is corrected from the start based on the injection amount error learned during the previous operation from the engine start, and the target injection amount is set.

As a result, it is possible to reduce the injection amount error at the time of starting to reduce the amount of generation of smoke and particulates, and to ensure stable startability.

In the second invention, a target injection amount is obtained by adding a value obtained by multiplying an injection amount error learned at the time of previous operation at start-up by a learning value reflection gain at start-up to the basic fuel injection amount. An injection amount error at the time of starting can be reduced, and stable starting performance can be ensured.

In the third invention, a value obtained by multiplying the injection amount error learned during the previous operation by the learned value reflection gain at the start is added to the basic fuel injection amount until a predetermined time elapses from the start. By calculating the target injection amount, the injection amount error at the time of startup and at the time of warm-up can be reduced, and stable start-up and warm-up properties can be ensured.

In the fourth invention, by setting the learning value reflection gain at the start according to the sign of the injection amount error learned during the previous operation, it is possible to prevent the fuel injection amount from being excessively reduced at the start, Stable startability can be secured.

In the fifth aspect of the invention, by setting the learning value reflection gain at the time of starting to be smaller as the fuel temperature is higher, the fuel injection amount is excessively reduced at the time of starting in response to the internal pressure fluctuation of the fuel injection pump. And stable startability can be secured.

In the sixth aspect of the present invention, the actual equivalent injection amount is determined according to the input state of various parameters, and accurately reflects the actual idle injection amount corresponding to an auxiliary load, an electric load, and the like. Since the injection amount error is sequentially learned, it is possible to compensate for a variation factor including a change over time in the fuel injection characteristic, and to always calculate the injection amount error with high accuracy.

Therefore, the target injection amount corrected on the basis of the injection amount error exactly matches the actual injection amount, and the fuel injection amount is controlled from the start to an optimum fuel injection characteristic according to the operating conditions of the engine. As a result, generation of smoke and particulates can be suppressed, and stable startability can be ensured.

[0029]

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

First, FIG. 26 shows a fuel injection system for a diesel engine.

In FIG. 26, a feed pump 6 for pre-pressurizing the fuel is mounted on an input shaft 6a of a fuel injection pump 1 which is driven to rotate in synchronization with the engine rotation, and is coaxially identical with the input shaft 6a. And a plunger 2 connected so as to reciprocate in the axial direction while being rotated.

The feed pump 6 sends out the pressurized fuel to the pump chamber 7, and the excess fuel is returned to a fuel tank (not shown) to keep the pressure in the pump chamber 7 constant.

A face cam 2a having cam lobes corresponding to the number of cylinders is provided coaxially on the plunger 2. The plunger 2 reciprocates in the axial direction each time the face cam 2a rides on the roller 8a. For example, in the case of a six-cylinder engine, when the input shaft 6a makes one rotation, the face cam 2a rides on the roller 8a six times during this time, and the plunger 2 reciprocates six times. Each time the plunger 2 reciprocates, it draws fuel into the plunger chamber 2b and pressurizes it. A return spring 2k pushes back the plunger 2 against the face cam 2a.

In the extension stroke of the plunger 2, fuel from the pump chamber 7 is sucked into the plunger chamber 2b through the fuel stop valve 10 and the slit 2j provided in the plunger 2.

On the other hand, in order to feed the pressurized fuel in the plunger chamber 2b to the fuel injection nozzle during the compression stroke of the plunger 2, the plunger chamber 2b is moved along the axis of the plunger 2.
b, a communication passage 2c is formed. The communication passage 2c has a high-pressure passage 2d that branches off in the radial direction on the way.
A discharge passage 2e penetrating in the radial direction is also formed at the distal end.

Ports 2g of a number corresponding to the number of engine cylinders are equally arranged on the inner periphery of the cylinder 2f around the plunger 2 so as to be selectively connected to the high pressure passage 2d according to the rotational position of the plunger 2. A delivery valve 2h (only one is shown) is connected to each of the ports 2g, and fuel is fed from the delivery valve 2h to a fuel injection nozzle (not shown).

The plunger 2 reciprocates six times each time it rotates, and pressurizes the inhaled fuel each time. The pressurized fuel is pushed into the high-pressure passage 2d from the communication passage 2c. The pressurized fuel is fed to the port 2g, and the fuel is fed to the fuel injection nozzle via the corresponding delivery valve 2h.

On the other hand, a control sleeve 3 is slidably fitted on the outer periphery of the plunger 2 and normally covers the discharge passage 2e, and is closed. The passage 2e is released. As a result, the pressure in the plunger chamber 2b is released, and the pressure feed of the fuel from the delivery valve 2h to the fuel injection nozzle 11 ends.

Therefore, the amount of fuel sent to the fuel injection nozzle changes depending on the position of the control sleeve 3. If the release passage 2e is released early when the plunger 2 moves in the compression direction, the fuel injection amount is small. Conversely, when the release timing of the discharge passage 2e is delayed, the fuel injection amount increases.

In order to control the fuel injection amount, a rotary solenoid 4 for freely changing the position of the control sleeve 3 is provided. The rotary solenoid 4 is supplied with a fuel injection signal from a controller 18 and responds accordingly. To change the position of the control sleeve 3. The position of the control sleeve 3 is detected by the position sensor 5 and is fed back to the controller 18.

Next, the position of the face cam 2a on the roller 8a on which the face cam 2a rides is controlled by the timer piston 8 in the circumferential direction. In addition,
The illustrated timer piston 8 is rotated by 90 degrees from the actual position for convenience of explanation. A low-pressure chamber 8b and a high-pressure chamber 8c are provided on both sides of the timer piston 8, and the pressure in the high-pressure chamber 8c is adjusted by controlling the amount of a part of the high-pressure fuel released to the low-pressure chamber 8b by the control valve 9. Thus, the position of the timer piston 8 changes.

When the position of the timer piston 8 changes and the position of the roller 8a is advanced in the rotation direction of the face cam 2a,
The position at which the face cam 2a rides on the roller 8a is relatively delayed, and the timing of starting pressurization of the fuel by the plunger 2, that is, the fuel injection timing is delayed.
If the position of the roller 8a is delayed in the direction opposite to the rotation of the roller, the pressure start timing by the plunger 2 is advanced, and the fuel injection timing is advanced.

The signal from the controller 18 controls the operation of the control valve 9 in accordance with the operation state, adjusts the position of the timer piston 8, and controls the advance and retard of the fuel injection timing.

The controller 18 includes the fuel injection nozzle 1
1, a nozzle lift sensor 12 for detecting a valve opening timing and a lift amount, a fuel temperature sensor 15 for detecting a temperature of fuel supplied to the fuel injection pump 1, a cooling water temperature sensor 13 for detecting an engine cooling water temperature, and an accelerator opening. Signals from an accelerator opening sensor 16 for detecting the degree, a rotation speed sensor 14 for detecting the pump rotation speed, and the like are input, and control signals for the fuel injection amount and the injection timing are calculated and output based on these signals.

With respect to the fuel injection amount controlled by the controller 18, the target injection amount determined according to the operating state and the target injection amount based on the target injection amount signal are set so as to coincide with each other. Modify the injection quantity as follows.

In FIG. 1, reference numeral 101 denotes a unit for detecting an operating state including an engine speed, an accelerator opening (load), and the like, and reference numeral 102 denotes a unit for calculating a basic fuel injection amount from each of these outputs. . Reference numeral 103 denotes a unit for determining an idle operation state from an output of an idle switch or the like. Reference numeral 104 denotes a starter switch, an ignition switch, a power steering switch, an electric load signal, a neutral switch, an air conditioner switch, a fuel temperature, an engine coolant temperature, a vehicle speed, and the like. This is a means for inputting various parameters from a power supply voltage and an engine speed sensor.

Reference numeral 105 denotes an actual equivalent for calculating an injection amount expected to be actually injected in order to maintain the target rotation speed during idling operation under various conditions based on the output of the various parameter input means 104. This is means for calculating the actual fuel injection amount of the injection amount.

Reference numeral 106 denotes the fuel injection amount calculating means 10 described above.
2. An idling state fuel correcting means for correcting the injection amount based on signals from the idle state determining means 103 and the various parameter input means 104 so as to match the target rotation speed during idling operation.

Reference numeral 107 denotes a permission of learning based on the outputs of the idle state determination means 103 and the various parameter input means 104 so as to learn the fuel injection amount error only under specific conditions in the idle operation state, as described later. This is injection amount error determination means for performing determination.

108 is an actual equivalent injection amount calculating means 105
Based on the outputs of the idle fuel correcting means 106 and the learning permission determining means 107, the fuel is calculated from the difference between the corrected idle fuel injection quantity and the predicted actual equivalent injection quantity in the operating state in which the learning is permitted. It is an injection amount error calculating means for calculating an error of the injection amount.

In this case, for example, when the air conditioner is operating, the amount of fuel injection required to maintain the idle speed at the target speed is larger than when the air conditioner is not operating. The injection amount also changes depending on the input parameter, and is larger when the air conditioner is operating than when it is not operating. Therefore, these deviations of the injection amount correspond to errors of the injection amount excluding the influence of the air conditioner load and the like.

Reference numeral 111 denotes an injection amount storage means for storing the fuel injection amount error calculated by the injection amount error calculation means 108 even when the operation is stopped.

Reference numeral 109 denotes an injection amount calculating means for correcting the fuel injection amount based on the output of the fuel injection amount calculating means 106 and the injection amount error calculating means 108 based on the injection amount error and setting a target injection amount.

Then, as the gist of the present invention, the injection amount calculating means 109 corrects the fuel injection amount from the start based on the injection amount error stored in the injection amount storing means 111, and sets the target injection amount. It is configured to be set.

The learning value reflection gain setting means 112 sets the learning value reflection gain at the time of starting, and the injection amount correcting means 109 outputs the injection amount error learned during the previous operation from the time of starting until a predetermined time has elapsed. Is added to the basic fuel injection amount to obtain a target injection amount.

The target injection amount is adjusted by the final injection amount setting means 110 so as to be within a predetermined range with respect to the basic injection amount, and the fuel injection means 111 performs the fuel injection according to the finally determined target injection amount. Control the amount.

Here, these control contents will be described in more detail according to the following flowchart.

FIG. 2 is a flow chart for calculating the final fuel injection amount output to the fuel injection pump 1, and the processing is performed at a timing synchronized with the engine rotation (Ref).
Synchronous operation).

In step 1, a basic fuel injection amount is calculated (to be described in detail later with reference to FIG. 3). Step 2
Then, the maximum injection amount is limited with respect to the fuel injection amount (described in detail with reference to FIG. 8). In step 3, a permission determination is made as to whether or not to learn the error in the fuel injection amount.
This learning permission will be described later with reference to FIGS. In step 4, when learning is permitted, an error in the fuel injection amount is calculated as described later (see FIG. 15).
20 will be described with reference to FIG. 20).

In step 5, a corrected injection amount Qsolh is calculated from the fuel injection amount in which the maximum injection amount is regulated and the injection amount error (described in detail with reference to FIG. 24).

In this way, the injection amount Qsolh in which the error of the fuel injection amount is corrected is obtained and output as the control signal of the fuel injection pump 1, each of which will be described in detail later.

FIG. 3 is a flowchart for calculating the basic fuel injection amount, and the processing is performed at a timing synchronized with the engine rotation (Ref synchronous calculation).

At steps 1 and 2, the engine speed Ne and the accelerator opening Cl are read.
Based on e and Cl, the fuel injection amount is set from a map as shown in FIG. 4 and is set as Mqdrv. Step 4
Then, the fuel injection amount Mqdrv is increased by the engine coolant temperature or the like, and the basic fuel injection amount Qsol1 is corrected.
And In step 5, the idle state is determined based on the output of a switch that determines the idle state, for example, a switch that detects the fully closed position of the accelerator. If the engine is in the idle state, the process proceeds to step 6, where the fuel injection amount is corrected so that the engine speed Ne becomes equal to the target engine speed Nset in the idle state, and the corrected value is referred to as Qsol2.
And

The setting of the target idle speed Nset will be described with reference to FIG.

On the other hand, when it is not in the idle state, Qsol1 is replaced with Qsol2, and the process is terminated.

FIG. 5 is a flow chart for setting the target idle speed Nset in the idling operation state (Ref).
Synchronous operation).

In step 1, the water temperature Twn is read. In step 2, a target idle speed Nset is set based on Twn from a table as shown in FIG. 6 (the lower the water temperature, the higher the target speed). finish.

FIG. 7 shows a flow for regulating the above basic injection amount based on the relationship with the allowable maximum injection amount (Ref synchronous calculation).

In step 1, the target injection amount Qsol2 is compared with the maximum injection amount Qful obtained as shown in FIG. 8, and when Qsol2 is large, the process proceeds to step 2, where Qful is used as the fuel injection amount Qsol. Qs
When ol is small, the process proceeds to step 3 and Q
Qsol2 is set to sol, and the process ends.

FIG. 8 is a flowchart for calculating the final maximum fuel injection amount Qful (Ref synchronous calculation).

In step 1, the engine speed Ne is read, and in step 2, the limit excess air ratio Klamb is set based on this Ne, for example, from a table as shown in FIG. In step 3, the intake air amount Qac per cylinder obtained as described later (see FIG. 12) is read, and in step 4, the maximum injection amount is calculated using the Qac and Klamb as follows.

Qful = (Qac / Klamb) /14.7 When Qful is calculated in this way, the processing is terminated.

FIG. 10 is a flowchart for calculating the intake air amount.

At step 1, the output voltage Us of the air flow meter is read, and at step 2, from the voltage flow rate conversion table as shown in FIG. 11, it is converted into the intake air amount Qas0_d based on this Us. Further, in step 3, the weighted averaging process of Qas0_d is performed to obtain Qas0, and the process ends. This processing is performed, for example, for 4 ms.
It is executed at predetermined time intervals such as ecJOB.

FIG. 12 is a flowchart for calculating the amount of air flowing into the cylinder based on the amount of intake air. (Ref
Synchronous operation).

At step 1, the engine speed Ne is read, and at step 2, the air amount Qas0 and Ne is converted into the intake air amount Qac0 per intake stroke according to the following equation.

Qac0 = (Qas0 / Ne) × KC
However, KC is a constant. In step 3, delay processing for a transport delay from the air flow meter (intake air amount measuring means) to the intake collector is performed as Qac = Qac0 _nL . Where L is a constant. In step 4, delay processing corresponding to the dynamics in the collector is performed by the following equation to calculate the intake air amount Qac per cylinder.

Qac = Qac _n-1 × (1-KV) + Qacn × KV
However, KV is a constant.

Next, the calculation and learning of the error of the fuel injection amount will be described with reference to FIGS.

First, FIGS. 13 and 14 are flowcharts for determining whether or not learning of an error in the fuel injection amount is permitted (Ref synchronous calculation).

This permission determination is made by detecting various conditions during idling as follows.
First, in step 1, the engine start switch STS
It is determined whether or not W is on, and when cranking is on, the process proceeds to step 16, where the learning permission counter Ctrlrln is set to a predetermined value TMRLRN #. On the other hand, if the ignition switch is not on, the process proceeds to step 2, and it is determined whether or not the ignition switch IGNSW is on. If it is off (the engine is stopped), the process proceeds to step 16 described above. If it is on, at step 3 the idle switch IDLES
It is determined whether W is on.

If the idle switch is on, the routine proceeds to step 4, where it is determined whether the vehicle speed VSP is zero. If not, the routine proceeds to step 16 as described above. If the vehicle speed is zero (vehicle stopped state), the routine proceeds to step 5, where the engine speed Ne is reduced to the idling target speed Nset by a predetermined value NL.
It is determined whether the value is smaller than the value obtained by adding RNH #.
If the number of rotations is low, the process proceeds to step 6, but if not, the process proceeds to step 16.

In step 6, the engine speed N
e from the idle target rotation speed Nset to a predetermined value NLRNL #
It is determined whether it is greater than the value obtained by subtracting. If the rotational speed is higher than this, the process proceeds to step 7; otherwise, the process proceeds to step 16.

As described above, when the idling speed is within the predetermined range based on the target idling speed, the routine proceeds to step 7.

In step 7, the power supply voltage Vb is set to a predetermined value VB
Compared to LRN #, if the power supply voltage is equal to or higher than the predetermined value, the process proceeds to step 8; otherwise, the process proceeds to step 16.

In step 8, the engine cooling water temperature Tw is compared with a predetermined value TWLRNH #. If the temperature is lower than the predetermined value, the process proceeds to step 9;
Move to 6. In step 9, the cooling water temperature Tw is compared with a predetermined value TWLRNL #, which is lower than the above-mentioned TWLRNH #. When the temperature is higher than this, that is, when the engine cooling water temperature is within a predetermined range, the process proceeds to step 10, but when not so, Moves to step 16.

In step 10, the fuel temperature Tfn is compared with a predetermined value TFLRNH #. If it is lower than this, the process proceeds to step 11, but if it is higher, the process proceeds to step 16.

In step 11, the fuel temperature Tfn is compared with a predetermined value TFLRNL # lower than the TFLRNH #. When the fuel temperature Tfn is higher than this, that is, when the fuel temperature is within a predetermined range, the process proceeds to step 12. Otherwise, the process also proceeds to step 16.

In step 12, the power supply voltage Vb is VBQLL
After confirming that it is higher than #, go to step 13
Judge whether the power steering switch PWSTSW is on,
When the power is off, that is, when the power steering is not operating, the process proceeds to step 14, and when the electric load, for example, the headlight or the defogger is off, the process proceeds to step 14.
If there is a load including accessories and the like in steps 13 and 14, the process proceeds to step 16.

When the engine is idling and there is no load such as auxiliary equipment, the learning permission state counter Ctrrn is decremented in step 15, that is, Ctrln = Ctrln-1.
To determine if the counter Ctrlrln is greater than zero. If zero, the process proceeds to step 18 to set a learning permission flag, that is, Flgqln = 1, but if it is larger than zero, the process proceeds to step 19, where the learning permission flag is cleared, and Flgqln = 0 is set. The process ends.

In this manner, the engine is idling in an appropriate range, and as described later, a load is not applied to auxiliary equipment and the like except for a neutral switch and an air conditioner switch, and this state is maintained for a predetermined time. When continued, the learning permission flag is set, and error learning of the fuel injection amount is permitted.

FIG. 15 is a basic flow for calculating the error of the fuel injection amount (Ref synchronous calculation).

First, in step 1, a learning value reflection gain Glqfh, which will be described in detail later, is calculated (see FIG. 16). The learning permission flag Flgql described above in step 2
Looking at the state of n, if the flag Flgqln = 1, the process proceeds to Step 3, and if cleared, the process proceeds to Step 5.

If learning is permitted, step 3
The fuel injection amount Qso necessary to maintain the target rotation speed in the idling state and considered to be actually supplied
lib (described in detail in FIG. 19). Further, in step 4, as shown in FIG.
Calculate and learn qsol ￥.

Then, at step 5, the injection amount error Dqso
11 is calculated as Dqsoll = Dqsol ￥ × Glqfh.

If the learning is not permitted, the process proceeds from step 2 to step 5, where the previous learning value D
The injection amount error Dqsoll is calculated using qsolｓ.

FIG. 16 is a flowchart for calculating the learning value reflection gain Glqfh for stabilizing the calculated injection amount error (Ref synchronous calculation).

In step 1, the start switch STAR
It is determined whether or not the TSW is on.
Clear tmrst.

When the start switch STARTSW is off, the ignition switch is turned on in step 2
It is determined whether or not W is on. If not, the process is terminated because the learning learning value reflection gain Glqfh is set to 0 because the operation of the engine is stopped.

When the engine is running in which the start switch STARTSW is turned off and the ignition switch IGNSW is turned on, the routine proceeds to step 3, where it is determined whether or not the timer Ctmrst after starting has become equal to or greater than a predetermined value TMRST #.

If the timer Ctmrst after starting is equal to or greater than the predetermined value TMRST #, the process proceeds to step 4 to determine whether or not the idle switch IDLESW is on. If not, the process proceeds to step 7; It is determined whether the vehicle speed VSP is zero. If the vehicle speed VSP is not zero, the process proceeds to step 7, but if the vehicle speed VSP is zero, the learning learning value reflection gain Glqf is determined in step 6.
The processing ends with h = 1.0.

If the vehicle speed VSP is not zero, the learning value reflection gain Glqfh is read in step 7 from the engine speed Ne and the injection amount Qsol using, for example, a learning value reflection gain map as shown in FIG. finish.

In the learning value reflection gain map shown in FIG. 17, the learning value reflection gain Glqfh approaches 1.0 as the operating condition is closer to the idle state, and decreases as the load becomes higher and the engine speed becomes higher. Evaluate the error small.

When the timer Ctmrst has a predetermined value TMRST #
For a while after the engine is started, the routine proceeds to step 9 where the timer Ctmrst is incremented. In step 11, for example, the learning value reflection gain correction from the fuel temperature Tf is performed using a fuel temperature correction coefficient table as shown in FIG. The coefficient Kgtf is read.

In the fuel temperature correction coefficient table shown in FIG. 18, the learning value reflection gain correction coefficient Kgtf is set to increase as the fuel temperature Tf decreases.

From the start of the engine to a while after the start of the engine, the routine proceeds to step 12, where it is determined whether the injection amount error Dqsol # learned during the previous operation is a positive value or a negative value. In step 13, the learning value reflection gain Glqfh is calculated as Gl from the learning value reflection gain correction coefficient Kgtf and the learning value reflection gain GLQFHP # at the start.
While qfh = Kgtf × GLQFHP #, if it is a negative value, the routine proceeds to step 14, where the learning value reflection gain correction coefficient Kgtf and the learning value reflection gain GLQ at the time of starting are calculated.
The learning value reflection gain Glqfh is set to Glqfh from FHM #.
= Kgtf × GLQFHM #, and the process ends.

Next, FIG. 19 is a flow for calculating the actual equivalent injection amount Qsolid which is assumed to be actually injected in the idling operation state (Ref synchronous calculation).

In step 1, it is determined whether the neutral switch NeutSW of the transmission is on. If the neutral switch is on, the process proceeds to step 2; if it is off, the process proceeds to step 5.

In step 2, the air conditioner switch A / CS
It is determined whether or not W is on. If it is off, the process proceeds to step 3, where the injection amount Qsolib = QSOLL0 #, and if it is on, Qsolib = QSOLL1 #.

On the other hand, in step 5, it is determined whether or not the air conditioner switch is on. If the air conditioner switch is off, the process proceeds to step 6, and if it is on, the injection amount Qsolib = QSOLL2 #.
The process ends.

The injection amount Qsolib is relatively large when the vehicle is not in neutral, and relatively large when the air conditioner switch is on.

[0112] These injection amounts are expected injection amounts in an idling operation state that are required in advance by design or the like and are necessary to maintain the idle speed at the target speed.
The injection amount increases as the auxiliary equipment load increases.

By the way, the signals from the neutral switch and the air conditioner switch are excluded from the learning permission determination conditions in FIGS. 13 and 14 described above.
In the idle state where learning is permitted, in this example, 4
The actual equivalent injection amount is set for each of the three conditions. As described later, learning of the injection amount error is performed in order to improve the stability and reliability of the control.
The weighted average of what was done for the two conditions is taken.

In this example, the conditions are determined from the neutral switch and the air conditioner switch, and the actual equivalent injection amount is calculated. In addition, for example, a power steering switch, an electric load signal, a neutral switch, an air conditioner switch, Based on the fuel temperature, engine coolant temperature, power supply voltage, engine speed sensor, etc., the actual equivalent injection amount in the idle operation state, which is expected under each condition, can be set in the same manner. As the number increases, the stability of the learning accuracy increases.

However, when these input parameters change, the learning permission conditions are also different, and those that fall within the input conditions of the actual equivalent injection amount are excluded from the learning conditions.

FIG. 20 is a flowchart for calculating the injection amount error learning value Dqsol # based on the basic fuel injection amount and the actual equivalent injection amount (Ref synchronous calculation).

First, in step 1, a weighted average time constant correction coefficient (rotational integration weight correction coefficient) Klsne is set based on the integrated value SNe of the engine rotation from the time of production based on a table as shown in FIG.

This table characteristic reduces the learning gain in the unstable state at the time of the initial operation of the engine, and when the operation of the engine becomes stable over time, the correction coefficient becomes 1.0 (no correction). Become.

In step 2, the travel distance SV from the time of production is
A weighted average time constant correction coefficient (travel distance weight correction coefficient) KLsvsp is set from sp, for example, from a table as shown in FIG. This table characteristic is also for removing an unstable element at the time of the initial operation of the engine, and the correction coefficient approaches 1.0 according to the traveling distance.

In step 3, a weighted average time constant correction coefficient (elapsed time weight correction coefficient) Klsst from the operating time SSttm from the time of engine production is set from a table as shown in FIG. Also in this case, the learning gain in the unstable state at the time of the initial operation of the engine is set to be small.

Note that each of these weight correction coefficients Klsne,
Regarding KLsvsp and Klsst, not all of them are required, and at least one may be obtained.

Next, in step 4, the neutral switch N
It is determined whether or not euSW is on. If it is on, the process proceeds to step 5, and if it is off, the process proceeds to step 8. In each case, it is determined whether the air conditioner switch A / CSW is on.

In step 5, if the air conditioner switch is on, the process proceeds to step 6, where the basic value Klcon corresponding to the weighted average time constant is set to KLC0 #.
To set Klcon to KLC1 #. In step 8, when the air conditioner switch is on, the process proceeds to step 9 and the basic value Klcon corresponding to the weighted average time constant is set to KLC2 #. When it is off, the process proceeds to step 10 and Klcon is set to KLC3 #.

As described above, the learning gain is adjusted according to the conditions such as the load of the auxiliary equipment, and the influence of the learning error when the conditions are different is reduced.

In step 11, the basic value Klcon corresponding to the weighted average time constant and the weight correction coefficient K
From lsne, KLsvsp, and Klsst, a value Klc corresponding to the weighted average time constant is calculated as Klc = Klcon × Klsn.
The calculation is performed as e × KLsvsp × Klsst. In step 12, this Klc is limited to a value of 0 or more and 1 or less, that is, if it exceeds this range, it is limited to 0 at the minimum value and 1 at the maximum value.

In step 13, the basic fuel injection amount Qsol
2 and the actual equivalent injection amount Qsolib, and the difference is defined as Dqsol0. That is, Dqsol0 = Q
sol2-Qsolib.

That is, in a predetermined idling operation state, the difference Dq in the fuel injection amount from the fuel injection amount necessary to maintain the target rotation speed and the actual equivalent injection amount at that time.
sol0 is calculated.

In step 14, the injection amount error learning value Dqsol # is obtained by performing a weighted average process using the deviation Dqsol0 and the load average time constant equivalent value Klc. That is, Dqsol ￥ = Dqsol ￥ n−1 ×
The calculation is performed as (1−Klc) + Dqsol0 × Klc.

As described above, in the predetermined idling operation state in which the learning is permitted, the fuel injection amount corrected to maintain the target idle speed at that time and the auxiliary equipment load and the like are set. Based on the deviation from the actual equivalent injection amount, a deviation of the fuel injection amount is obtained, multiplied by a correction value, and further weighted averaged to obtain a learned value of the fuel injection amount error.

FIG. 24 is a flowchart for calculating the corrected injection amount based on the learning value of the injection amount error obtained as described above (Ref synchronous calculation).

In step 1, the basic fuel injection amount Qsol2
And the error learning value Dqsoll is read. In step 2, the basic injection amount is corrected according to the learning value as follows.
That is, the corrected injection amount Qsolh is calculated as follows: Qsolh = Qs
Calculated as ol2 + Dqsoll.

FIG. 24 is a flowchart for calculating the injection amount Qsolf finally output to the fuel injection pump 1 (Ref
Synchronous operation).

In this case, the corrected injection amount is regulated so as to be within a predetermined range with respect to the basic injection amount, thereby avoiding excessive correction of the fuel injection amount.

In step 1, the lower limit value obtained by multiplying the basic injection amount Qsol2 by a predetermined gain KQSOLM # of 1.0 or less is compared with the corrected injection amount Qsolh, and if Qsolh is smaller than the lower limit value. If it is larger, proceed to step 2, and if smaller, proceed to step 5.

In step 2, the upper limit value obtained by multiplying the basic injection amount Qsol2 by a predetermined gain KQSOLP # of 1.0 or more is compared with the corrected injection amount Qsolh, and if it is smaller than the upper limit value. Goes to step 3,
Final injection quantity Qsol for output to fuel injection pump 1
Qsolh is directly set as f.

On the other hand, the corrected injection amount Qsolh is
If it is determined in step 1 that the value is smaller than the lower limit, in step 5, Qsolf = Qsol2 ×
The final injection amount is set equal to the lower limit value as KQSOLM #.

In step 2, the corrected injection amount Q
When the value of soh is larger than the upper limit, Qsolf = Q
The final injection amount is set to the same value as the upper limit value as sol2 × KQSOLP #.

FIG. 25 is a map for converting the fuel injection amount Qsolf obtained in this way into an output signal for actually controlling the injection amount. The output signal (voltage) Uαsol increases as Qsolf increases. Become.

Next, the overall operation will be described.

In general, there is a variation in the production of the engine, a variation in the production of the fuel injection pump 1 and the fuel injection nozzle, or the deterioration thereof with the passage of time. Has an error.

When the injection amount error is large, the optimal fuel injection amount does not become the optimum fuel injection amount according to the operating condition. For example, when the actual injection amount is larger than the target injection amount in a high engine load region, for example, If a large amount of smoke is generated, or if the injection amount is small, the engine output may be insufficient such as during acceleration. Fluctuations also occur during fuel cut and recovery at the time of deceleration, and in some cases, the fuel at the time of recovery is insufficient and engine stalls.

In the present system, the target injection amount is calculated as follows in order to make the target injection amount coincide with the actual injection amount.

In the idle operation state, the basic fuel injection amount is set, and the fuel is pumped from the fuel injection pump 1 to the fuel injection nozzle of each cylinder and injected. At this time, in order to keep the idle speed constant, the engine speed is detected, and the fuel injection amount is corrected so that the detected speed matches the target constant speed.

In this case, if the target fuel injection amount calculated for maintaining the idling rotational speed constant and the actually supplied injection amount match, the correction amount should be zero, but the error is reduced. If there is, the correction amount is calculated correspondingly.
However, if there is an auxiliary load, the idle speed cannot be maintained constant unless the fuel is increased according to the auxiliary load. For this reason, the correction amount of the fuel injection amount includes a deviation amount from the actual injection amount and a change amount of the auxiliary equipment load and the like.

Therefore, the error between the fuel injection amount calculated for setting the idle rotation speed to the target rotation speed and the actual fuel injection amount cannot be determined simply from the correction amount alone.

Therefore, based on various parameters in the idle state, for example, a neutral switch, an air conditioner switch, a power steering switch, an electric load signal, a coolant temperature, a fuel temperature, and the like, a constant idle speed is maintained under these input conditions. An actual equivalent injection amount corresponding to the actual fuel injection amount required for the above is obtained. This is to predict the injection amount required to maintain the idle speed constant in each case when there is an auxiliary equipment load or the like.

When the power steering switch and the air conditioner switch are turned on, a load is applied to the engine, and the fuel injection amount required to maintain the idling speed constant is relatively increased. Therefore, the actual equivalent injection amount obtained according to these becomes closer to the actual fuel injection amount.

Next, under the idling condition, an error in the injection amount is calculated based on a deviation between the fuel injection amount corrected to maintain the actual idle speed constant and the actual equivalent injection amount. . The actual equivalent injection amount has a different value depending on the condition of the accessory load at that time, and therefore, a value obtained by subtracting the actual equivalent injection amount from the corrected injection amount is an injection amount error that does not include the auxiliary load. It is equivalent to only minutes.

In general, the error in the injection amount is caused by various causes such as variation in production of the engine, the fuel injection pump 1 and the fuel injection nozzle, or deterioration over time.

Therefore, when the injection amount error is obtained in this way and the target injection amount is calculated from the error and the basic injection amount, the target injection amount exactly matches the actual injection amount. If the fuel injection amount is controlled based on the amount, an optimum fuel injection amount can be obtained according to the operating state of the engine.

As a result, an increase in smoke and particulates due to an error in the fuel injection amount is prevented, and the drivability during recovery after fuel cut is improved.

The calculation of the error of the fuel injection amount is performed in a state where certain learning conditions are satisfied. However, the learning permission conditions include that the auxiliary load and electric load of the engine are small, By selecting a time when the water temperature, the fuel temperature, the power supply voltage, and the like are within a predetermined range and continue for a predetermined time, learning can be performed in a stable state with few errors.

On the other hand, with some input parameters, for example, a neutral switch and an air conditioner switch, the cases are classified under each condition, and the injection amount error is calculated by comparing with the obtained actual equivalent injection amount. In addition, since the final injection amount error is calculated and learned as the load average value, the variation in the learned value is small, and the reliability is improved. Furthermore, in this learning, the integrated value of the engine speed, the mileage, the elapsed time after production, etc. are taken in as correction values, so the fluctuations due to deterioration over time are taken into account, and the stability and reliability of the learning values are only that much. Increase.

Further, in obtaining the final fuel injection amount in relation to the learning value, the basic fuel injection amount is regulated so as to fall within a predetermined range, so that the injection amount is excessively corrected. And the stability of the control is improved.

By the way, in the conventional system, the fuel injection amount is not corrected by the learning value at the time of the previous operation at the time of starting, and therefore, as shown in FIG. 27, the variation of the injection amount is large and the actual injection amount is excessive. As a result, a large amount of smoke may be generated, or the injection amount may be insufficient to start the engine.

The present invention corrects the fuel injection amount from the start based on the injection amount error stored during the previous operation from the engine start and sets the target injection amount.

As a result, as shown in FIG. 27, the injection amount error at the time of starting is reduced, and the actual fuel injection amount becomes excessive, thereby suppressing the generation of smoke and particulates. This prevents the engine from being unable to start due to lack of power, and ensures stable startability.

For a while after the start of the engine, for a while after the start, different learning value reflection gains are set when the learning value in the previous operation is a positive value and a negative value, and the fuel temperature is lowered. Therefore, by setting the learning value reflection gain large, it is possible to prevent the fuel injection amount from being excessively reduced in response to the internal pressure fluctuation of the fuel injection pump 1 at the time of starting and warming up, and to achieve stable starting and warming up. Can be secured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a flowchart for calculating a final fuel injection amount.

FIG. 3 is a flowchart for calculating a basic fuel injection amount.

FIG. 4 is a characteristic diagram showing basic fuel injection amount characteristics.

FIG. 5 is a flowchart for setting a target idle speed.

FIG. 6 is a characteristic diagram of a target idle speed.

FIG. 7 is a flowchart for regulating a maximum fuel injection amount.

FIG. 8 is a flowchart for setting a maximum fuel injection amount.

FIG. 9 is a characteristic diagram in which a limit excess air ratio is set.

FIG. 10 is a flowchart for detecting an intake air amount.

FIG. 11 is a voltage conversion characteristic diagram of an intake air amount.

FIG. 12 is a flowchart for calculating a cylinder intake air amount.

FIG. 13 is a flowchart for determining whether to permit learning of a fuel injection amount error.

FIG. 14 is also a flowchart.

FIG. 15 is a flowchart for calculating a fuel injection amount error.

FIG. 16 is a flowchart for calculating a learning value reflection gain.

FIG. 17 is a characteristic diagram of a learning value reflection gain.

FIG. 18 is a flowchart for calculating an actual equivalent injection amount.

FIG. 19 is a flowchart for calculating an error learning value.

FIG. 20 is a characteristic diagram of a learning weight coefficient.

FIG. 21 is a characteristic diagram.

FIG. 22 is a characteristic diagram.

FIG. 23 is a flowchart for calculating a fuel correction injection amount.

FIG. 24 is a flowchart for calculating a final injection amount.

FIG. 25 is a characteristic diagram in which an injection amount and a voltage conversion characteristic are set.

FIG. 26 is a schematic configuration diagram of a fuel injection pump according to an embodiment of the present invention.

FIG. 27 is an explanatory diagram showing a control example at the time of starting.

[Explanation of symbols]

 102 Fuel injection amount calculation means 103 Idle state determination means 104 Various parameter detection means 105 Actual equivalent injection amount calculation means 106 Idle fuel injection amount correction means 107 Learning permission determination means 108 Injection amount error calculation learning means 109 Target fuel injection amount Calculation means 111 Injection amount error storage means 112 Learning value reflection gain setting means

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 45/00 340 F02D 45/00 340H 358 358E

Claims (6)

[Claims] A means for detecting an engine operation state; a means for calculating a basic fuel injection amount based on the engine operation state; a means for judging an idle state of the engine; Means for correcting the idle fuel injection amount so that the following conditions are satisfied: means for determining whether to permit learning of a fuel injection amount error when a predetermined condition is satisfied in an idle state; and Means for calculating and learning the injection amount error, means for storing the injection amount error learned during the previous operation even after the operation is stopped, and basic fuel injection based on the injection amount error learned from the start to the previous operation. A fuel injection control device for an internal combustion engine, the fuel injection control device comprising: an injection amount correcting unit that corrects an amount to set a target injection amount. Means for setting a learning value reflection gain at start-up, wherein said injection amount correction means multiplies an injection amount error learned at the time of previous operation by a learning value reflection gain at start-up. The fuel injection control device for an internal combustion engine according to claim 1, wherein the target injection amount is obtained by adding the target injection amount to the basic fuel injection amount. 3. An injection amount correcting means for setting a learning value reflection gain at the time of starting, wherein the injection amount correcting means starts the injection amount error based on an injection amount error learned during a previous operation during a predetermined time from the start. 3. The fuel injection control device for an internal combustion engine according to claim 1, wherein a target injection amount is obtained by adding a value multiplied by a learning value reflection gain at the time to the basic fuel injection amount. 4. The internal combustion engine according to claim 2, wherein the learning value reflection gain setting means sets the learning value reflection gain at the time of starting according to the sign of the injection amount error learned during the previous operation. Fuel injection control device. 5. The fuel injection control device for an internal combustion engine according to claim 2, wherein the learning value reflection gain setting means sets the learning value reflection gain at the time of starting to decrease as the fuel temperature increases. . 6. An apparatus for detecting various parameters in an idle state, wherein said actual equivalent injection amount calculating means includes a fuel injection unit required to maintain a target engine speed in an idle state according to the detected various parameters. 5. The fuel injection control device for an internal combustion engine according to claim 1, wherein an actual equivalent injection amount corresponding to the amount is calculated.