JPH07174039A - Fuel injection device of engine - Google Patents

Abstract

PURPOSE:To improve the evaporative atomization condition of fuel inside a combustion chamber regardless of a purge quantity for the intake system of vapor fuel. CONSTITUTION:A fuel injection device is formed by providing an injection control means for controlling operation of a fuel injection device 4 so as to increase an integrated value per hour required for reaching of fuel, to a combustion chamber 3, sequentially injected by the fuel injection device 4 to an intake passage 1a, in comparison with the time integral value when a supply quantity of vapor fuel is large, when the supply quantity of the vapor fuel by a vapor fuel supply means 5 is small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection system for an engine, and more particularly to a measure for improving the state of vaporization and atomization of fuel in a combustion chamber of an engine when the purge amount of evaporated fuel in the intake system is small.

[0002]

2. Description of the Related Art Generally, in an automobile, in order to prevent the vaporized fuel generated in a fuel tank or the like from being released into the atmosphere as it is, the vaporized fuel is adsorbed and held in a canister or the like. The evaporated fuel is purged into the intake system at an appropriate time during engine operation. That is, in a vehicle equipped with a fuel injection engine, the evaporated fuel purged into the intake system mixes with the fuel injected from the fuel injection device, is introduced into the combustion chamber of each cylinder, and burns. And the exhaust gas is
It will be released into the atmosphere after being purified by the catalyst device.

By the way, when the evaporated fuel is purged into the intake system, the amount of fuel is increased by that amount, and the air-fuel ratio of the air-fuel mixture becomes rich, which causes fluctuations in idle rotation and catalyst unit. Problems such as a decrease in purification performance are likely to occur. Therefore, in the past, in practice
As is known from Japanese Patent Publication No. 6, the evaporative fuel is purged into the intake system only when the air-fuel ratio feedback control is being performed, which makes it possible to perform the purge regardless of the presence or absence of the purge and the amount of the purge. The air-fuel ratio of the air-fuel mixture in the combustion chamber can be maintained at the target air-fuel ratio.

[0004]

However, in the above-mentioned conventional example, the air-fuel ratio of the air-fuel mixture can be maintained at the target value, but the vaporized state of the fuel in the combustion chamber tends to become unstable. That is, while the evaporated fuel is in a sufficiently vaporized state, the fuel injected into the intake system is not yet in a sufficiently vaporized state. Therefore,
When the purge amount is large, the vaporization state of the air-fuel mixture becomes good as a whole, but simply injecting the amount of fuel commensurate with the decrease in the purge amount will worsen the vaporization atomization state of the fuel in the combustion chamber. It becomes.

The present invention has been made in view of the above problems, and an object thereof is to improve the state of vaporization and atomization of fuel in a combustion chamber regardless of the amount of purge of vaporized fuel to the intake system. To be able to do it.

[0006]

In order to achieve the above object, in the invention of claim 1, the fuel injected from the fuel injection means reaches the combustion chamber when the supply amount of the evaporated fuel to the intake system is small. In the meantime, the time required for the vaporization can be sufficiently secured, and by this, the vaporized atomization state of the fuel in the combustion chamber is improved.

Specifically, in the present invention, as shown in FIG. 1, fuel injection means 4 for injecting fuel into an intake passage communicating with a combustion chamber 3 of an engine 1 and an engine based on various conditions are used to evaporate fuel vapor. It is premised on the fuel injection device of the engine provided with the evaporated fuel supply means 5 for supplying to the intake system 2 of 1.

When the amount of the evaporated fuel supplied by the evaporated fuel supply means 5 is small, the amount of the fuel sequentially injected by the fuel injection means 4 into the intake passage is larger than that when the amount of the evaporated fuel supplied is large. The injection control means 6 for controlling the operation of the fuel injection means 4 is provided so that the integrated value of each time required to reach the combustion chamber 3 becomes large.

According to a second aspect of the present invention, in the above first aspect of the invention, the injection control means 6 is used when the amount of vaporized fuel supplied by the vaporized fuel supply means 5 is small compared to when the amount of vaporized fuel supplied is large. The fuel injection timing of the fuel injection means 4 is advanced from the intake stroke to the front side.

According to the invention of claim 3, in the invention of claim 1, the fuel injection means 4 divides the fuel for one cycle into the combustion chamber 3 into a plurality of times before and after the start timing of the intake stroke. In the case of the injection, the injection control means 6 controls the intake stroke of the fuel injection means 4 when the supply amount of the evaporated fuel by the evaporated fuel supply means 5 is smaller than that when the supplied amount of the evaporated fuel is large. The division ratio for the injection amount for one cycle is changed so that the injection amount before the start becomes larger than the injection amount after the start.

According to a fourth aspect of the present invention, in the above-mentioned first aspect of the invention, the fuel injection means 4 has a pre-intake injection region in which fuel is injected before the start of the intake stroke and an intake air in which fuel is injected after the start of the intake stroke. When the injection timing is switched based on a preset injection timing switching line for dividing the injection region, the injection control means 6 is
When the amount of evaporated fuel supplied by the evaporated fuel supply unit 5 is small, the injection timing switching line is changed to the intake injection region side as compared with the case where the amount of evaporated fuel supplied is large.

[0012]

With the above construction, in the invention of claim 1, the fuel is injected into the intake passage of the engine 1 by the fuel injection means 4 and becomes a mixture with the air taken into the intake system 2 to form each combustion chamber. Introduced in 3. On the other hand, the evaporated fuel is supplied to the intake system 2 by the evaporated fuel supply means 5, and this evaporated fuel is also mixed with the injected fuel and the intake air and introduced into each combustion chamber 3. When the amount of vaporized fuel supplied by the vaporized fuel supply means 5 is small, the operation of the fuel injection means 4 is controlled by the injection control means 6, whereby the fuel injection means 4 is sequentially supplied to each intake port. The integrated value of each time required to reach the combustion chamber 3 of the injected fuel is made larger than that when the supply amount of the evaporated fuel is large. That is, the vaporization time of the injected fuel is increased as a whole by increasing the integrated value, and as a result, the sufficiently vaporized and atomized fuel is introduced into the combustion chamber 3. As a result, the vaporized atomization state of the fuel in the combustion chamber 3 is improved even when the supply amount of the evaporated fuel is small.

On the other hand, when the supply amount is large, the integrated value of each time required for the injected fuel to reach the combustion chamber 3 is reduced, so that the atomization and atomization of the injected fuel is suppressed. Therefore, the fuel in the combustion chamber 3 is prevented from becoming an excessive vaporization atomization state, and the deterioration of the intake charging efficiency and the accompanying reduction in output due to such an excessive vaporization atomization state are prevented in advance. .

In the second aspect of the invention, the evaporated fuel supply means 5
When the amount of vaporized fuel supplied by the fuel cell is small, the injection control unit 6 advances the fuel injection timing of the fuel injection unit 4 from the intake stroke of each cylinder to the front side compared to when the amount of vaporized fuel supplied is large. As a result, fuel is injected even before the start of the intake stroke. The fuel injected before this start is prevented from flowing into the combustion chamber 3 by the intake valve that is closed at the intake port until the intake stroke is started, so that the combustion of the injected fuel is correspondingly increased. The integrated value of each time required to reach the chamber 3 is increased as a whole. Therefore, even when the supply amount of the evaporated fuel is small, the vaporized atomization state of the fuel in the combustion chamber 3 is improved. On the other hand, when the supply amount is large, the injection timing is not advanced as much as when the supply amount is small, and therefore vaporization of the injected fuel is suppressed, so that excessive vaporization fog of the fuel in the combustion chamber 3 is suppressed. It becomes possible to avoid the activated state.

According to the third aspect of the invention, the fuel for one cycle for each combustion chamber 3 is divided into a plurality of times before and after the start timing of each intake stroke and injected by the fuel injection means 4. When the supply amount of the evaporated fuel by the evaporated fuel supply unit 5 is small, the injection control unit 6 changes the split ratio of the injection amount of the fuel injection unit 4 before the start of the intake stroke to the injection amount for one cycle, The injection amount before the start of the intake stroke is larger than the injection amount after the start as compared with the case where the supply amount of the evaporated fuel is large. As a result, the injection amount before the start of the intake stroke is increased, and the integrated value of each time required to reach the combustion chamber of the injected fuel is increased by that amount as a whole. Therefore, even when the supply amount of the evaporated fuel is small, the vaporized atomization state of the fuel in the combustion chamber 3 is improved. On the other hand, when the supply amount is large, the injection amount before the start of the intake stroke is suppressed as compared to when the supply amount is small, which ensures a sufficient injection amount after the start of the intake stroke and expands the correction range. Will be done. Therefore, even when it becomes necessary to significantly reduce the fuel injection amount for one cycle after the fuel injection before the start of the intake stroke, such as during deceleration, it becomes possible to sufficiently cope with the fuel accuracy. Can be secured.

In the invention of claim 4, the injection timing of the fuel injection means 4 is switched on the basis of an injection timing switching line which divides the pre-intake region and the intake injection region, and the fuel is taken in the intake stroke in the pre-intake region. Is injected before the start of, and in the intake region after the start of the intake stroke. When the supply amount of the evaporated fuel by the evaporated fuel supply means 5 is small, the injection timing switching line is changed by the injection control means 6 to the intake injection region side as compared with the case where the supplied amount of the evaporated fuel is large. . As a result, when the supply amount of the evaporated fuel is small, a large amount of the fuel is injected before the start of the intake stroke, which improves the vaporized atomization state of the fuel in the combustion chamber 3. On the other hand, when the supply amount is large, the injection timing switching line is located closer to the pre-intake injection region than when the supply amount of the evaporated fuel is small, which causes excessive fuel vaporization mist in the combustion chamber 3. It is possible to prevent the output from decreasing due to the activated state.

[0017]

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

(Embodiment 1) FIG. 2 shows a fuel injection device for an engine according to Embodiment 1, in which 1 is an engine, 2 is an intake system of the engine 1, and 11 is an exhaust system of the engine 1. . The intake system 2 includes an air flow meter 12, a throttle valve 13, and a surge tank 14 for detecting an intake air amount Q along intake passages 1a that guide intake air from an air cleaner (not shown) to each combustion chamber 3 of the engine 1.
Are provided in order from the upstream side. Further, a bypass passage 1b that bypasses the throttle valve 13 and guides intake air to the engine 1 is installed in parallel in the intake passage 12, and the ISC valve (idle speed /
A control valve) 15 is provided. The injector 4a of the fuel injection device 4 that injects fuel toward the rear surface of each intake valve 17 that opens and closes the intake port 16 is located at a position immediately upstream of the intake port 16 that communicates with each combustion chamber 3 in the intake passage 11. Are arranged respectively.
Fuel having a constant pressure is supplied to the fuel injection device 4 by a fuel supply device (not shown), and the fuel is injected by opening the injection port of the injector 4a for a time corresponding to the pulse width of the input fuel injection signal. It is done like this.

On the other hand, in the exhaust system 11, the oxygen concentration in the exhaust gas is detected for feedback control of the air-fuel ratio of the air-fuel mixture along the exhaust passage 11a that guides the exhaust gas from each combustion chamber 3 to the atmosphere. The O ₂ sensor 19 and the catalyst device 20 for purifying the exhaust gas are sequentially provided toward the downstream side. In the figure, 21 is an exhaust port communicating with each combustion chamber 3, and 22 is an exhaust valve that opens and closes the exhaust port 21.

Further, an evaporative fuel supply means 5 for supplying evaporative fuel to the intake system 2 is connected to the surge tank 14 in series. That is, the evaporated fuel supply means 5 has one end connected to the fuel tank 23 and the other end connected to the surge tank 1
4 and an evaporative fuel passage 24 for guiding the evaporative fuel in the fuel tank 23 to the surge tank 14, and an evaporative fuel passage provided in the middle of the evaporative fuel passage 24 and guided from the fuel tank 23 through the evaporative fuel passage 24. A canister 25 that adsorbs fuel, and a purge valve that is provided in the vaporized fuel passage 24 between the canister 25 and the surge tank 14 and that adjusts the purge amount when the vaporized fuel released by the canister 25 is supplied to the surge tank 14. 26 and. The purge valve 26 is composed of a duty solenoid and can adjust the purge amount according to an input signal.

The output signals of the air flow meter 12 and the O ₂ sensor 19 are sent to the ECU 27 (engine
Input to the control unit). And
The ECU 27 is configured to output a control signal to each of the ISC valve 15, the fuel injection device 4, and the purge valve 26 to control them. The fuel injection signal, which is a control signal output from the ECU 27 to the fuel injection device 4, is a pulse wave, and the number of fuel injections in each injector 4a increases with an increase in the number of pulses, and the fuel injection signal increases by 1 with an increase in the pulse width. The injection amount per time is designed to increase. In addition, the ECU 27
Is connected to the IG coil 28 so that an ignition signal can be output. The IG coil 28 has one end connected to the positive terminal of the battery (not shown) and the other end connected to the distributor 2
9 are connected to the spark plugs 30 of the respective combustion chambers 3. Further, the distributor 29 is E
The ECU 27 is connected to the CU 27, so that the ECU 27 detects the engine speed N based on the crank angle signal from the distributor 29. The ECU
A water temperature sensor 32 that detects the temperature Tw of the cooling water in the water jacket 31 of the engine 1 is input to 27.

Next, the control operation for controlling the fuel injection device 4 in the ECU 27 will be concretely described based on the flow charts of FIGS. 3 and 4. First, the flowchart of FIG. 3 shows a control process when the evaporated fuel is supplied to the intake system 2. That is, in step S1, the water temperature sensor 32, the O ₂ sensor 19, the air flow meter 12
After reading the output signals of the distributor 29 and the like, it is determined in step S2 that the purge condition is satisfied. Here, the engine water temperature Tw is T
w ≧ 50 ° C., the operating region of the engine 1 reaches the air-fuel ratio feedback region, and the O ₂ sensor 19 is heated and activated, that is, the air-fuel ratio feedback control is actually performed. It judges based on the fact that it is. It should be noted that the fact that the engine 1 is in the feedback region is judged based on the engine speed N and the engine load. When the determination is YES, the process proceeds to step S3, while when the determination is NO, the process proceeds to step S4.

In step S3, the purge amount is set according to the operating condition. In this embodiment, it is set according to the intake air amount Q. Then, it progresses to step S5. On the other hand, in step S4, after setting the purge amount to 0,
Go to step S5. In step S5, a signal is output to the purge valve 26 of the evaporated fuel supply means 5 based on the set value of the purge amount, and then the process returns to step S1.

Here, the routine of the fuel injection control which is carried out at the time of controlling the purge amount of the evaporated fuel will be explained based on the flow chart of FIG. First, in step Sa1, each signal from the air flow meter 12, the distributor 29, etc. is read, and in step Sa2, a basic pulse of the fuel injection signal for each injector 4a of the fuel injection device 4 is calculated. In this calculation, for example, a value obtained by dividing the air inflow amount Q by the engine speed N is multiplied by a constant m (Q ÷ N ×
m) Then, in step Sa3, the correction amount of the pulse is calculated based on the engine water temperature Tw, the acceleration state, etc., and the final pulse is calculated in step Sa4.
It proceeds to step Sa5. In step Sa5, the basic injection timing is calculated based on the engine speed N, the load, and the like. For example, when the engine speed N is high or the load is large, it is set to the front side of the intake stroke.
Then, the process proceeds to step Sa6.

In step Sa6, as shown in FIG. 5, a correction amount for advancing the injection timing in each injector 4a from the intake stroke to the front side is calculated based on the purge amount. That is, when the purge amount is sufficiently large, the correction amount is set to 0, while when the purge amount is small, the correction amount is set in inverse proportion to the purge amount. That is, the smaller the purge amount is, the larger the correction amount is set.
The purge amount used here is the value set in steps S3 and S4 of the flowchart of FIG. Then, it progresses to step Sa7. In step Sa7, the final injection timing is calculated based on the correction amount. That is, the basic injection timing is set to the front side by the correction amount. Then, in step Sa8, it is determined that it is the injection timing, and when the determination is YES, the fuel injection is executed in step Sa9 while the determination is NO.
In case of, the process returns to the step Sa1.

In the above processing, the above step Sa6
And Sa7 constitute the injection control means 6 of the present invention. With this means 6, when the purge amount of the evaporated fuel by the evaporated fuel supply means 5 is small, the fuel injection timing of the fuel injection device 4 is large. Compared with the above, the exhaust stroke side immediately before each intake stroke is advanced according to the purge amount.

Therefore, in the first embodiment, the engine 1
When the purge amount of the evaporated fuel to the intake system 2 is small,
By making the integrated value of each time required for the fuel sequentially injected from the injector 4a of the fuel injection device 4 to reach the combustion chamber 3 larger than that when the purge amount is large, the vaporization time of the injected fuel is reduced. Since a large amount can be taken as a whole, sufficiently vaporized injected fuel can be introduced into the combustion chamber 3. That is, the fuel injection timing of the fuel injection device 4 is advanced to the exhaust stroke side immediately before the intake stroke in accordance with the small purge amount, so that the fuel is injected even before the intake stroke is started. Become. The fuel injected before this start is prevented from flowing into the combustion chamber 3 by the intake valve 17 which is closed at the intake port 16 until the intake stroke is started, so that the injected fuel is injected accordingly. The integrated value of each time until reaching the combustion chamber 3 can be increased as a whole. Therefore, even when the purge amount is small, the vaporized atomization state of the fuel in the combustion chamber 3 can be improved.

On the other hand, when the purge amount is large, the injection timing is not advanced as much as when the purge amount is small,
Therefore, the vaporization of the injected fuel can be suppressed, so that the fuel in the combustion chamber 3 can be prevented from being in an excessive vaporization atomization state, and the intake charging efficiency is deteriorated due to the excessive vaporization state, and accordingly It is possible to prevent the output from decreasing.

In the first embodiment, the operation of the fuel injection device is controlled based on the purge amount set by the ECU 27 in accordance with the operating state. However, the purge amount for detecting the purge amount in the intake system is determined. A detection means may be provided and the above-mentioned control may be performed based on the purge amount detected by this detection means.

In the first embodiment, when the purge amount is equal to or less than the predetermined value, the injection timing is advanced to the front side by the correction amount that is inversely proportional to the purge amount. The relationship with respect to does not have to be linear as described above.

(Embodiment 2) FIGS. 6 and 7 show a fuel injection control routine executed at the time of controlling the purge amount of the evaporated fuel in the engine fuel injection apparatus according to Embodiment 2 of the present invention. . Since the basic configuration of the fuel control system according to the second embodiment is the same as that of the first embodiment, the same parts are designated by the same reference numerals and detailed description thereof will be omitted.

In the second embodiment, the fuel injection device 4 divides the fuel supply amount for one cycle into each combustion chamber 3 into two injections before and after the start timing of each intake stroke. The operation is controlled by the ECU 27. Specifically, E
The fuel injection signal from the CU 27 basically rises at the leading pulse at BTDC (before top dead center) 180 ° before the start of the intake stroke and at at 6 ° ATDC (after top dead center) after the start. 2 with trailing pulse
As shown in FIG. 8, the engine speed N is divided.
The ratio between the leading pulse width and the trailing pulse width is changed according to. That is, when the engine speed N is low, there are only trailing pulses and no leading pulses. Then, as the engine speed N increases, the ratio of the leading pulse width increases, and in the high engine speed region, only the leading pulse is used this time.

Next, referring to the flow chart shown in FIG. 6, the first half of the fuel injection control, that is, the control processing of the leading pulse width, which is performed when the evaporated fuel purge amount is controlled, will be described. Since steps Sb1 to Sb4 are the same as steps Sa1 to Sa4 in FIG.
The description starts from b5. In this step Sb5, the basic division ratio of the leading pulse width based on the engine speed N is calculated with respect to the width of the final pulse calculated in step Sb4. Then, the process proceeds to the next step Sb6.

In step Sb6, a weighting factor for weighting the leading pulse width is set according to the engine speed N. This weighting coefficient is set in inverse proportion to the increase in the purge amount, as shown in FIG. That is, when the purge amount is sufficiently large, the weighting factor is 1.0
On the other hand, when the purge amount is smaller than a certain value,
Accordingly, the weighting coefficient is increased between 1.0 and 1.5. Then, the process proceeds to step Sb7.

In step Sb7, the basic division ratio is corrected by the correction division ratio to calculate the final division ratio. For example,
When the basic division ratio of the reading pulse width is 60% and the weighting factor thereof is 1.3, the final division ratio of the reading pulse width is 78% (= 60% × 1.3).
The final division ratio of the trailing pulse width at this point is 22% (= 100% -78%). Next, in step Sb8, the divided pulse is calculated based on the final pulse and the final division ratio. That is, the trailing pulse width is calculated. Then, the process proceeds to step Sb9 to execute the injection before the start of the intake stroke, and the process ends.

In the above processing, the above step Sb6
And Sb7 constitute the injection control means 6 of the present invention, whereby when the purge amount is small, the injection amount before the start of the intake stroke due to the leading pulse of the fuel injection device 4 is larger than the tray amount. The division ratio of the injection amount before the start of the intake stroke to the injection amount for one cycle, that is, the division ratio of the leading pulse width to the final pulse width is changed so that it becomes larger than the injection amount after the start by the ring pulse. .

Next, based on the flowchart of FIG.
The latter half of the fuel injection control will be described. Incidentally, step S
Since c1 to Sc4 are the same as steps Sa1 to Sa4 in FIG. 4, the description will be started from step Sc5. In step Sc5, the width of the divided pulse, that is, the trailing pulse is calculated. Specifically, the above step Sc
The leading pulse width is subtracted from the width of the final pulse calculated in 4. Therefore, when the final pulse width is changed due to acceleration / deceleration of the vehicle after the leading injection, the trailing pulse width is also changed as compared with the calculation of the leading pulse width. Then, in step Sc6, the injection after the start of the intake stroke is executed, and the processing ends therewith.

Therefore, in the second embodiment, the fuel injection device 4 supplies the fuel for one cycle to each combustion chamber 3 twice before and after the start timing of each intake stroke by the leading pulse and the trailing pulse of the fuel injection signal. When the fuel injection amount is divided into two parts, when the purge amount is small, the splitting ratio of the leading pulse width, which determines the fuel injection amount before the start of the intake stroke, is corrected to an increased state. The injection amount before starting can be increased. As a result, the integrated value of each time until the injected fuel reaches the combustion chamber 3 can be increased by that amount as a whole, so that the vaporization state of the air-fuel mixture in the combustion chamber 3 is improved even when the purge amount is small. can do.

On the other hand, when the purge amount is large, the injection amount before the start of the intake stroke due to the leading pulse is suppressed as compared with when the purge amount is small, so that the injection amount after the start of the intake stroke due to the trailing pulse is sufficient. This can be ensured, and the correction range will be expanded. This allows
For example, when decelerating or the like, it becomes possible to sufficiently cope with the case where it is necessary to significantly reduce the injection amount per cycle after fuel injection before the start of the intake stroke,
Fuel accuracy can be secured.

In the second embodiment, the fuel for one cycle for each combustion chamber 3 is divided into two parts before and after injection, but, for example, the fuel is divided into three parts before and after injection. May be.

(Third Embodiment) FIG. 10 and FIG. 11 show a fuel injection control routine executed when controlling the purge amount of the evaporated fuel in the engine fuel injection apparatus according to the third embodiment. Since the basic configuration of the fuel control device of the third embodiment is the same as that of the first embodiment, the same parts are designated by the same reference numerals.

In the third embodiment, the fuel injection device 4 includes an exhaust stroke injection region as a pre-intake injection region for injecting fuel during the exhaust stroke immediately before the start of the intake stroke, and an intake stroke injection region for injecting fuel during the intake stroke. The injection timing is switched based on the injection timing switching line that divides the area machine. Specifically, as shown in FIG. 12, the exhaust stroke injection region is set to the low load side and the low engine speed N side, and conversely, the intake stroke injection region is set to the high load side. Side and the side where the engine speed N is high are set. Both regions are partitioned by the injection timing switching line α, and the engine speed N
When the value of the load with respect to the value is less than or equal to the line α, exhaust injection is performed, and when it exceeds the value, intake injection is performed.

Next, the routine of the fuel injection control which is carried out at the time of controlling the purge amount of the evaporated fuel will be explained based on the flow charts of FIGS. Incidentally, step Sd1
Since Sd4 is the same as steps Sa1 to Sa4 in FIG. 4, the description will be started from step Sd5 in FIG. In step Sd5, it is determined that purging is in progress. This determination is performed using the determination result in step S2 of the flowchart of FIG. That is, when the determination in step S2 is YES, the determination in step Sd5 is also YES, and when the determination in step S2 is NO, it is also determined as NO. When the determination is YES, the process proceeds to step Sd6, while when the determination is NO, the process proceeds to step Sd7.

In step Sd6, the injection timing switching line α that divides the exhaust injection region and the intake injection region
Is set to A indicated by the solid line in FIG. On the other hand, in step Sd7, the exhaust injection region is expanded to the intake injection region side. That is, the injection timing switching line α that divides the exhaust injection region and the intake injection region is set to B shown by a virtual line in FIG.

Based on the injection timing switching line α set in step Sd6 or Sd7, it is determined in step Sd8 of FIG. 11 that the load T is equal to or less than the line α. When the determination is YES, the process proceeds to step Sd9.
On the other hand, if the determination is NO, the process proceeds to step Sd10.
Then, in step Sd9, the injection timing is set to the exhaust injection region. On the other hand, in step Sd10,
Set to the intake injection region. Then, the process proceeds to step Sd11, it is determined that it is the injection timing, and the determination is YE.
In the case of S, the process proceeds to the next step Sd12, the injection is executed, and then the process returns to step Sd1. On the other hand, when the determination is NO, the process directly returns to step Sd1.

In the above processing, the above step Sd7
Configures the injection control means 6 of the present invention so that when the purge is not being performed, the injection timing switching line α is changed to the intake injection region side compared to when the purge is being performed.

Therefore, in the third embodiment, when the injection timing of the fuel injection means 4 is switched based on the injection timing switching line α, and the evaporated fuel is not purged, the injection timing switching line α is sucked. Since it is changed to the injection region side (the side indicated by B in FIG. 12), exhaust gas can be injected into the intake injection region when the evaporated fuel is not supplied to the intake system 2 in the portion close to the exhaust injection region. As a result, the vaporized atomization state of the fuel in the combustion chamber 3 can be improved. On the other hand, during the purging, the injection timing switching line α moves to the side of the exhaust injection region (the side indicated by A in the figure), which causes excessive vaporization and atomization of the fuel in the combustion chamber 3. It is possible to prevent the output from decreasing due to the state.

In the third embodiment, the entire injection timing switching line is changed to the intake injection region side.
You may make it change partially.

In the third embodiment, the injection before intake is set during the exhaust stroke immediately before intake, but it may be set during the combustion stroke or compression stroke immediately before intake.

Further, in the third embodiment, the injection timing switching line is changed based on the presence or absence of the purge amount, but it may be changed based on the predetermined purge amount, or depending on the purge amount. May be gradually changed.

[0051]

As described above, according to the first aspect of the invention, the fuel injection means for injecting fuel into the intake passage communicating with the combustion chamber of the engine and the evaporated fuel of the engine are introduced into the intake passage based on various conditions. In an engine fuel injection device including an evaporated fuel supply means for supplying to a system, when the amount of evaporated fuel supplied by the evaporated fuel supply means is small, the operation of the fuel injection means is changed compared to when it is large. The integrated value of each time required to reach the combustion chamber of the injected fuel is set to be larger than that when the supply amount is large, so that the injected fuel can be sufficiently vaporized and introduced into the combustion chamber. Even when the supply amount of the evaporated fuel is small, the vaporization atomization state of the fuel in the combustion chamber can be improved, while when the supply amount is large, the vaporization atomization of the injected fuel is suppressed and the fuel inside the combustion chamber is suppressed. Since There can be avoided the excessive vaporization atomization state, it is possible to prevent deterioration and decrease in output associated therewith intake air charging efficiency due to such excessive vaporization atomization state.

According to the second aspect of the invention, when the supply amount of the evaporated fuel is small, the fuel injection timing is advanced from the intake stroke to the front side compared to when the supply amount of the evaporated fuel is large. When the intake stroke is small, fuel can be injected before the start of the intake stroke, and the fuel injected before the start of the intake stroke is allowed to flow into the combustion chamber by the intake valve that is closed at the intake port until the start of the intake stroke. It is possible to prevent the increase of the integrated value of each time until the injected fuel reaches the combustion chamber as a whole, while suppressing the vaporization of the injected fuel due to the advance when the amount of the evaporated fuel supplied is large. be able to.

According to the third aspect of the present invention, in the case where the fuel injection means injects fuel for one cycle into the combustion chamber divided into a plurality of times before and after the start timing of the intake stroke. The injection control means changes the division ratio of the fuel injection amount before the start of the intake stroke to the fuel injection amount for one cycle when the supply amount of the evaporated fuel is small so that the fuel injection amount before the start of the intake stroke evaporates. Since the fuel injection amount after the start is larger than that when the fuel supply amount is large, when the supply amount of the evaporated fuel is small, the injection amount before the intake stroke start before the intake stroke start is increased. It is possible to increase the integrated value of each time until the injected fuel reaches the combustion chamber as a whole, while suppressing the injection amount before the start of the intake stroke when the supply amount is large. Intake line Since the injection amount after the start can be sufficiently secured and the correction range can be expanded, when the fuel injection amount for one cycle is largely cut after the fuel injection before the start of the intake stroke, for example, during deceleration. However, it becomes possible to sufficiently cope with it, and it is possible to secure fuel accuracy.

According to the fourth aspect of the present invention, the fuel injection means defines a pre-intake injection region for injecting fuel before the start of the intake stroke and an intake injection region for injecting fuel after the start of the intake stroke. In order to switch the injection timing based on a preset injection timing switching line for this purpose, the injection control means causes the injection timing switching line to change the injection timing from the injection timing switching line compared to when the supply amount of evaporated fuel is small. Since it is changed to the region side, when the supply amount of the evaporated fuel is small, the fuel is injected before the start of the intake stroke and reaches the combustion chamber of the injected fuel even in the portion of the intake injection region near the pre-intake injection region. It is possible to increase the integrated value of each time up to the whole, while the injection timing switching line is on the pre-intake injection region side when the supply amount is large. It is possible to suppress the vaporization fuel atomization morphism.

[Brief description of drawings]

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

FIG. 2 is an overall configuration diagram showing a fuel injection device for an engine according to a first embodiment of the present invention.

FIG. 3 is a flowchart showing a control process of a purge amount of evaporated fuel.

FIG. 4 is a flowchart showing a control process of fuel injection during purge amount control.

FIG. 5 is a characteristic diagram showing a relationship between a purge amount and an injection timing correction amount.

FIG. 6 is a flow chart showing a fuel injection leading pulse control process at the time of purge amount control in the engine fuel injection device according to the second embodiment of the present invention.

FIG. 7 is a flowchart showing a trailing pulse control process for fuel injection. .

FIG. 8 is a characteristic diagram showing the basic division ratio of the leading pulse width and the trailing pulse width in the fuel injection signal together with the level of the engine speed.

FIG. 9 is a characteristic diagram showing a relationship between a weighting coefficient and a purge amount with respect to a reading pulse width.

FIG. 10 is a flowchart showing a first half of a fuel injection control process at the time of purge amount control in the engine fuel injection device according to the third embodiment of the present invention.

FIG. 11 is a flowchart showing the latter half of the fuel injection control process.

FIG. 12 is a characteristic diagram showing an exhaust injection region and an intake injection region.

[Explanation of symbols]

 1 Engine 2 Intake System 3 Combustion Chamber 4 Fuel Injection Device (Fuel Injection Means) 5 Evaporative Fuel Supply Means 6 Injection Control Means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuaki Tanaka 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Motor Corporation

Claims (4)

[Claims] 1. A fuel for an engine, comprising: a fuel injection means for injecting fuel into an intake passage communicating with a combustion chamber of the engine; and an evaporated fuel supply means for supplying evaporated fuel to an intake system of the engine based on various conditions. In the injector, when the amount of vaporized fuel supplied by the vaporized fuel supply means is small, as compared with when the amount of vaporized fuel supplied is large, the fuel is sequentially injected into the combustion chamber of the fuel injected into the intake passage by the fuel injection means. A fuel injection device for an engine, comprising: injection control means for controlling the operation of the fuel injection means so that the integrated value of each time required to reach the value becomes large. 2. The fuel injection device for an engine according to claim 1, wherein the injection control means controls the fuel consumption when the amount of evaporated fuel supplied by the evaporated fuel supply means is smaller than when the amount of evaporated fuel supplied is large. A fuel injection device for an engine, characterized in that the fuel injection timing of the injection means is advanced from the intake stroke to the front side. 3. The fuel injection device for an engine according to claim 1, wherein the fuel injection means injects fuel for one cycle into the combustion chamber divided into a plurality of times before and after the start timing of the intake stroke. The injection control means, when the supply amount of the evaporated fuel by the evaporated fuel supply means is small, compared to when the supplied amount of the evaporated fuel is large, the injection amount before the intake stroke of the fuel injection means starts after the start. The fuel injection device for an engine, wherein the division ratio for the injection amount for one cycle is changed so as to be larger than the injection amount of. 4. The engine fuel injection device according to claim 1, wherein the fuel injection means has a pre-intake injection region for injecting fuel before the start of the intake stroke and an intake injection region for injecting fuel after the start of the intake stroke. The injection control means switches the injection timing based on a preset injection timing switching line in order to divide the fuel injection amount, and the injection control means controls the supply amount of the evaporated fuel when the supply amount of the evaporated fuel by the evaporated fuel supply means is small. A fuel injection device for an engine, characterized in that the injection timing switching line is changed to a side closer to the intake injection region as compared with the case where the number of fuel injections is large.