JP3047594B2 - Fuel injection type internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection type internal combustion engine.

[0002]

2. Description of the Related Art A first fuel injection valve for injecting fuel into an engine intake passage and a second fuel injection valve for constantly injecting fuel into an engine combustion chamber are provided. An internal combustion engine is known in which fuel injection from a first fuel injection valve is stopped when the load is lower than a predetermined set load, and fuel is injected from the first fuel injection valve when the engine load is higher than the set load. (Japanese Patent Laid-Open No. 60-3041
No. 6). In this internal combustion engine, the total injection amount, which is the sum of the fuel injected from both fuel injection valves, is predetermined as a function of the engine load, and the total injection amount is increased as the engine load increases.

[0003]

However, in such an internal combustion engine, when the engine load becomes higher than the set load and the fuel injection from the first fuel injection valve is started, the first fuel injection valve is started.
Part of the fuel injected from the fuel injection valve adheres to the inner wall surface of the intake passage, and as a result, the amount of fuel supplied from the intake passage into the engine combustion chamber is smaller than the amount of fuel injected from the first fuel injection valve. Therefore, when fuel is injected from each fuel injection valve according to the injection amount predetermined as a function of the engine load as in this internal combustion engine, when the fuel injection from the first fuel injection valve is started, the fuel actually enters the engine combustion chamber. A problem arises in that the supplied fuel amount is smaller than the required fuel amount, and thus the output torque of the engine is temporarily reduced.

Further, in this internal combustion engine, even if the engine load becomes lower than the set load and the fuel injection from the first fuel injection valve is stopped, the fuel adhering to the inner wall surface of the intake passage is supplied to the engine combustion chamber. to continue. Therefore, when fuel injection is performed from each fuel injection valve in accordance with the injection amount predetermined as a function of the engine load as in this internal combustion engine, when the fuel injection from the first fuel injection valve is stopped, the fuel actually enters the engine combustion chamber. There is a problem that the supplied fuel amount becomes larger than the required fuel amount, and thus the output torque of the engine temporarily increases.

[0005]

According to the present invention, there is provided a first fuel injection valve for injecting fuel into an engine intake passage, and fuel injection into an engine combustion chamber. second; and a fuel injection valve, when the engine operating state is in the predetermined operating region the second fuel injection valve stops the fuel injection from the first fuel injection valve for
The fuel injected from the
In an internal combustion engine in which an air-fuel mixture is formed only in a predetermined region and fuel is injected from a first fuel injection valve when the operating state of the engine is out of a predetermined operation region, the first fuel injection is performed. Estimating the amount of fuel adhering to the inner wall surface of the intake passage when fuel injection from the valve is started, and
Means for estimating the amount of adhering fuel flowing into the engine combustion chamber when fuel injection from the fuel injection valve is stopped, wherein the second fuel is injected when fuel injection from the first fuel injection valve is started. adherent fuel amount described above by the fuel injected from the injection valve
Min with supplement, a fuel injection amount from the second fuel injection valve is to lose weight by inflow amount described above when the fuel injection from the first fuel injection valve is stopped.

[0006]

When the fuel injection from the first fuel injection valve is started, the amount of fuel actually supplied into the engine combustion chamber is increased by correcting the amount of fuel injected from the second fuel injection valve by the amount of adhered fuel. The required fuel amount, and when the fuel injection from the first fuel injection valve is stopped, the amount of fuel actually supplied to the engine combustion chamber by reducing and correcting the amount of fuel injected from the second fuel injection valve by the inflow amount Is the required fuel amount.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG.
The combustion chamber structure of each of the cylinders 1a is shown in FIGS. 2 to 4, reference numeral 2 denotes a cylinder block, 3 denotes a piston reciprocating in the cylinder block 2, 4 denotes a cylinder head fastened on the cylinder block 2, and 5 denotes a position between the piston 3 and the cylinder head 4. The formed combustion chamber, 6 is a pair of intake valves, 7a is a first intake port, 7b is a second intake port, 8 is a pair of exhaust valves,
Reference numeral 9 denotes a pair of exhaust ports, respectively. As shown in FIG. 2, an ignition plug 10 is disposed at the center of the inner wall surface of the cylinder head 4. A first fuel injection valve 11a for injecting fuel into the second intake port 7b is provided for each cylinder 1a, and a second fuel injection valve 11b is provided around an inner wall surface of the cylinder head 4. Is arranged. As shown in FIGS. 2 and 3, a shallow plate portion 12 having a substantially circular contour extending from below the second fuel injection valve 11 b to below the spark plug 10 is formed on the top surface of the piston 3, A deep plate portion 13 having a substantially hemispherical shape is formed at the center of the plate portion 12. Further, the shallow plate portion 12 and the deep plate portion 1 below the ignition plug 10 are provided.
A substantially spherical concave portion 14 is formed at the connection portion with the third portion 3.

As shown in FIG. 1, a first intake port 7a and a second intake port 7b of each cylinder 1a are connected to a surge tank 16 via respective intake branch pipes 15. The surge tank 16 is connected to an air cleaner 18 via an intake duct 17, and a throttle valve 20 connected to an accelerator pedal 19 is arranged in the intake duct 17. The electronic control unit 30 is composed of a digital computer, and is connected to the RAM via a bidirectional bus 31.
(Random access memory) 32, ROM (read only memory) 33, CPU (microprocessor) 34,
An input port 35 and an output port 36 are provided. A water temperature sensor 21 that generates an output voltage proportional to the engine cooling water temperature is attached to the engine body 1, and the output voltage of the water temperature sensor 21 is input to an input port 35 via an AD converter 37. A pressure sensor 22 that generates an output voltage proportional to the absolute pressure in the surge tank 16 is attached to the surge tank 16, and the output voltage of the pressure sensor 22 is input to an input port 35 via an AD converter 38.

A load sensor 23 for generating an output voltage proportional to the amount of depression of the accelerator pedal 19 is connected to the accelerator pedal 19, and the output voltage of the load sensor 23 is A
The data is input to the input port 35 via the D converter 39. The top dead center sensor 24 generates an output pulse when the first cylinder 1a reaches the intake top dead center, for example, and this output pulse is input to the input port 35. The crank angle sensor 25 generates an output pulse every time the crankshaft rotates 30 degrees, for example, and this output pulse is input to the input port 35. The CPU 34 calculates the current crank angle from the output pulse of the top dead center sensor 24 and the output pulse of the crank angle sensor 25, and calculates the engine speed from the output pulse of the crank angle sensor 25. On the other hand, the output port 36 is connected to each first fuel injection valve 11a and each second fuel injection valve 11b via the corresponding drive circuit 40.

In the embodiment according to the present invention, F _{1 in} FIG.
And from the second fuel injection valve 11b as indicated by F ₂ is the fuel injected toward the two directions, as from the first fuel injection valve 11a as shown in F ₃ in FIG. 4 the second intake port 7b Fuel is injected toward the inside. FIG.
The figure shows the fuel injection amount and the fuel injection timing from the fuel injection valve 11a and the second fuel injection valve 11b. In FIG. 5, Q _all represents the total injection amount. Total injection quantity Q _all as shown in FIG. 5 is the small engine low load operation than Q _a only fuel injection injection amount Q2 in the combustion chamber 5 from the second fuel injection valve 11b on the end of the compression stroke is performed. On the other hand, the total injection quantity Q _all are at the time of engine medium load operation between Q _a and Q _b injection amount Q1 only fuel injection is performed from the first fuel injection valve 11a into the second intake port 7b, the end of the compression stroke Fuel is injected from the second fuel injection valve 11b into the combustion chamber 5 by the injection amount Q2. That is, during the engine middle load operation, each fuel injection valve 1
Fuel injection is performed from 1a and 11b. The total injection quantity Q _all are subject to excessive engine high load operation than Q _b fuel by injection amount Q1 is injected from the first fuel injection valve 11a into the second intake port 7b. In FIG. 5, θS and θ
E indicates the injection start timing and the injection completion timing of the fuel injection Q2 performed by the second fuel injection valve 11b at the end of the compression stroke.

[0011] All injection quantity Q _all is a function of the depression amount A _cc and the engine speed N of the accelerator pedal 19, the depression amount A of the total injection quantity Q _all the accelerator pedal 19 as shown in FIG. 6 (A) _The total injection amount _Qall changes in accordance with the engine speed N as shown in FIG. 6B. Depression amount A _cc of total injection quantity Q _all the accelerator pedal 19, the relationship between the engine speed N is stored in advance in the ROM33 in the form of a map shown in FIG. 7 (A).

Further, a function of the depression amount A _cc and the engine speed N of the compression stroke injection amount Q2 even accelerator pedal 19 between Q _a and Q _b in FIG. 5, the compression stroke injection amount Q2 and the accelerator pedal 19 The relationship between the depression amount A _cc and the engine speed N is stored in advance in the ROM 33 in the form of a map shown in FIG. As shown in FIGS. 8A and 8B, Q _a and Q _b in FIG. 5 are both functions of the engine speed N, and the relationship shown in FIGS.
33.

As shown in FIG. 5, when the total injection quantity Q _all is Q
_During low engine load operation less than _a , fuel is injected into the combustion chamber 5 from the second fuel injection valve 11b at the end of the compression stroke. At this time, the injected fuels F ₁ and F ₂ collide with the peripheral wall surface of the deep dish portion 13 as shown in FIGS. 9 (A) and 9 (B). The fuel colliding with the peripheral wall surface of the deep dish portion 13 is vaporized and diffused by the swirling flow S, and as a result, as shown in FIG.
As shown in (C), an air-fuel mixture G is formed in the concave portion 14 and the deep dish portion 13. At this time, the inside of the combustion chamber 5 other than the concave portion 14 and the deep dish portion 13 is filled with air, and
At this time, it mixes only in a limited area around the spark plug 10
Qi G will be formed. Next, the mixture G is ignited by the spark plug 10.

On the other hand, in FIG. 5, the total injection amount Q _all is Q _a
And at the time of engine medium load operation is between Q _b fuel injection Q1 is performed by the first fuel injection valve 11a, the fuel injection Q2 of the second fuel injection valve 11b is made further to the end of the compression stroke. At this time, a uniform lean mixture is formed in the combustion chamber 5 by the fuel Q1 injected from the first fuel injection valve 11a, and the lean mixture is generated by the fuel injected from the second fuel injection valve 11b in FIG. The air-fuel mixture formed as shown in C) becomes a fire and is burned.

On the other hand, in FIG. 5, the total injection amount Q _all is Q _b
When the engine has a higher load than the first fuel injection valve 11a
Is performed, and the homogeneous mixture formed in the combustion chamber 5 by the fuel injection Q1 is ignited by the spark plug 10. FIG. 10A shows the total injection amount Q _all
5 shows the change in the compression stroke injection amount by the second fuel injection valve 11b, that is, the change in the in-cylinder injection amount Q2 and the port injection amount Q1 by the first fuel injection valve 11a, when Qa becomes larger than _Qa (FIG. 5). , FIG. 10 (B) cylinder injection amount Q2 and the port injection quantity when the total injection quantity Q _{al l} becomes less than Q _a Q1
Shows the change.

As shown in FIG. 10A, the total injection amount Q
_all is port injection Q1 by a number composed of the first fuel injection valve 11a than Q _a is started, this time in-cylinder injection amount Q2
If the in-cylinder injection amount Q2 is determined such that the sum of the injection amount Q1 and the port injection amount Q1 becomes the total injection amount _Qall , the in-cylinder injection amount Q2 decreases as shown by the broken line in FIG. However, in this case, even if the port injection Q1 is started, part of the fuel injected by the port injection Q1 adheres to the inner wall surface of the second intake port 7b, and therefore, the total fuel amount actually supplied to the combustion chamber 5 becomes It becomes smaller than the required total injection amount _Qall . As a result, when the port injection Q1 is started, the engine output torque temporarily decreases. Thus, in order to prevent the engine output torque from temporarily lowering in this manner, in the embodiment according to the present invention, the total fuel amount actually supplied into the combustion chamber 5 is set to the required total injection amount _Qall . total injection quantity as indicated by the solid line in 10 (a) Q _all are as a cylinder injection amount Q2 for increasing correction when it becomes more than Q _a. That is, in more general terms, the second fuel injector 1
Fuel adhering to the inner wall of the intake port due to fuel injected from 1b
The amount is compensated for.

[0017] This port injection Q1 by the total injection quantity Q _all is less than Q _a first fuel injection valve 11a as shown in FIG. 10 (B) is stopped against, this time in-cylinder injection amount Q2 If the in-cylinder injection amount Q2 is determined so that the total injection amount _Qall is equal to the total injection amount _Qall , the in-cylinder injection amount Q2 becomes
Changes as indicated by the broken line. However, in this case, even if the port injection Q1 is stopped, the second intake port 7b
The fuel adhering to the inner wall surface continues to flow into the combustion chamber 5, so that the total fuel amount actually supplied into the combustion chamber 5 becomes larger than the required total injection amount _Qall . As a result, when the port injection Q1 is stopped, the engine output torque temporarily increases. Therefore, in order to prevent the engine output torque from temporarily increasing in this way, in the embodiment according to the present invention, the total fuel amount actually supplied into the combustion chamber 5 is set so that the required total injection amount Q _all becomes equal to the required total injection amount Q _all . 10 total injection quantity Q _all as indicated by the solid line in (B) is so reduced to correct the in-cylinder injection amount Q2 when it becomes less than Q _a.

Here, the next problem is how much the in-cylinder injection amount Q2 should be increased or decreased so that the combustion chamber 5 is actually adjusted.
Is the amount of fuel supplied into the fuel tank coincides with the required total injection amount _Qall . The increase correction amount and the decrease correction amount depend on the amount of fuel adhering when the port injection Q1 is started and the amount of adhering fuel flowing into the combustion chamber 5 when the port injection Q1 is stopped. The deposits and inflows are difficult to measure and therefore have to be estimated. Therefore, a method for estimating the fuel adhesion amount and the inflow amount will be described next.

The fuel quantity Q _m adhered to the inner wall surface of the second intake port 7b when First port injection Q1 is started
In consideration of the above, it is considered that the amount of fuel deposited by one port injection Q1 increases as the port injection amount Q1 increases, so that the amount of fuel deposited by one port injection Q1 decreases to the port injection amount Q1. It will be proportional. On the other hand, it is considered that the lower the temperature of the inner wall surface of the second intake port 7b, the larger the amount of adhered fuel increases. Therefore, the amount of adhered fuel is inversely proportional to the temperature of the inner wall surface of the second intake port 7b. Meanwhile adherent fuel amount and the temperature is approximately proportional to the engine coolant temperature T _w of the inner wall surface of the second intake port 7b is 11
At the engine cooling water temperature T as indicated by f ₂ (T _w ).
It will be inversely proportional to _w . As described above, the amount of fuel deposited by one port injection Q1 is equal to the port injection amount Q.
Proportional to 1, the amount of fuel deposited by a single port injection Q1 is inversely proportional to the engine coolant temperature T _w is Q1 · f (T
_w ). Therefore adherent fuel amount Q _m when port injection Q1 is performed Tsugitsugini is Q1 · f
(T _w ). The relationship shown in FIG. 11 is stored in the ROM 33 in advance.

Meanwhile, initially the port injection Q1 is started adherent fuel amount Q _m adherent fuel amount Q _m reaches equilibrium with the although increasing pleasure interim becomes constant. Maximum value Q of the adherent fuel amount Q _m, i.e. adherent fuel amount Q _m when the equilibrium is reached
_max is the absolute pressure PM and the temperature of the inner wall surface of the second intake port 7b, i.e. the engine function of coolant temperature T _w of the second intake port 7b. That is, the absolute value PM in the second intake port 7b
Since the evaporation of adhering fuel is promoted as the value of
As shown in (A), the higher the absolute pressure PM in the second intake port 7b, the larger the maximum value _Qmax . on the other hand,
As shown in FIG. 12B, the maximum value _Qmax increases as the engine cooling water temperature _Tw decreases. The maximum value Q _max indicated by FIG. 12 (A) and (B), the absolute pressure PM, the relationship between the engine coolant temperature T _w is stored in advance in the ROM33 in the form of a map as shown in FIG. 12 (C) ing.

By the way, as described above, when the port injection Q1 is started, the amount of the deposited fuel gradually increases, and when the equilibrium state is reached, that is, when the maximum value _Qmax is reached, the deposited fuel enters the combustion chamber 5. Think to start the inflow. The amount of fuel does not flow into the combustion chamber 5 when the port injection Q1 is started Considering this manner will be represented by the difference between the maximum value Q _max as the adherent fuel amount Q _m (Q _max -Q _m) Therefore, when the port injection Q1 is started, the in-cylinder injection amount Q2 is changed to (Q
_max -Q _m) the amount of fuel supplied to only increase correction them if actually the combustion chamber 5 will correspond to the required total injection quantity Q _all.

Next, when the port injection Q1 is stopped.
At this time, the inner wall surface of the second intake port 7b
The fuel adhering above gradually flows into the combustion chamber 5.
At this time, the inflow amount Q of the attached fuel flowing into the combustion chamber 5_nIs
First, the amount of deposited fuel Q_mIs considered to be proportional to
You. Further inflow Q_nIs the depression amount A of the accelerator pedal 19
_ccIncrease as the intake air volume increases
Inflow Q_nIn FIG. 13 (A)
f (A_cc), The accelerator pedal 19 is depressed.
Amount_ccWill be proportional to Also, the inflow Q_nIs the
2Increases as the temperature of the inner wall surface of intake port 7b increases
Inflow Q_nIs shown in FIG.
And f₁(T_w), The engine cooling water temperature T_wBut
It is thought that it increases as the height increases. Therefore the flow
Quantity Q_nIs Q_m・ F (A_cc) · F (T_w)
That is, when the port injection Q1 is stopped, the in-cylinder injection
Q2_m・ F (A_cc) · F (T_w) Just weight loss correction
Then, the amount of fuel actually supplied to the combustion chamber 5 becomes the required total injection.
Radiation Q_allWill match. Note that FIG.
And the relationship shown in (B) is stored in the ROM 33 in advance.
ing.

FIGS. 14 to 17 show a routine for controlling the fuel injection. This routine is executed by interruption every 180 crank angles. Referring first to FIG. 14, first in step 50, FIG.
Request based on the maps shown in (A) the total injection quantity Q _all are calculated. Next, at step 51, Q _a is calculated from the relationship shown in FIG.
_Qb is calculated from the relationship shown in (B). Next, at step 53, it is determined whether or not Q _all ≦ Q _a, that is, whether or not the vehicle is in a low load operation. If Q _all ≦ Q _a, the process proceeds to step 100 in FIG. 15, and if Q _all > Q _a , the process proceeds to step 54. In step 54, it is determined whether or not Q _all ≦ Q _b . When Q _all ≦ Q _b , that is, during engine middle load operation, the process proceeds to step 200 in FIG.
When _all> Q _b, i.e. at the time of engine high load operation proceeds to step 300 in FIG. 17.

Referring to FIG. 15, in step 100, the amount of deposited fuel Q _m , f calculated on the basis of FIG.
(A _cc ) and f calculated based on FIG.
Inflow Q _n of fuel deposited into the combustion chamber 5 is calculated by multiplying the (T _w). Then adherent fuel amount Q _m are still adhering by subtracting the inflow Q _n from step 101 the adherent fuel amount Q _m is calculated. Then whether step 102 adherent fuel amount Q _m becomes less than zero is determined. When Q _m ≦ 0, the routine proceeds to step 103, where Q _m = 0, and then proceeds to step 104.

In step 104, the inflow amount Q_nBut flame propagation
Limit Q_LTIt is determined whether the number is smaller than the number. This flame
Propagation limit Q_LTIs formed in the combustion chamber 5 by the adhering fuel
The minimum inflow that the flame can propagate through the mixture
And this flame propagation limit Q _LTIs predetermined.
Q_n<Q_LTIf so, go to step 105 and_n・ R _c
Is Q_nThen, the process proceeds to step 106. In addition,
R at step 105_cIs the entire mixture in the deep dish 13
Is burned at a depth of about 15 degrees after top dead center.
Ratio (υ / V) between the volume の of the plate 13 and the volume V of the combustion chamber 5
Represents. Inflow Q_nIs the flame propagation limit Q_LTThan
The fuel mixture that is burned when the fuel is
This is the mixture present in the plate 13, and
Quantity Q_nOf inflow Q contributing to combustion_nIs Q_n・
(Υ / V). Therefore, in step 105, Q_nTo R
_cInflow that actually contributes to combustion by multiplying by
Q_nThat you are looking for.

The cylinder injection amount Q2 is calculated by subtracting the inflow Q _n from step 106 requests the total injection quantity Q _all. Next, at step 107, the in-cylinder injection amount Q2
There whether less than injectable minimum injection quantity Q _min is determined. When Q2 ≦ Qmin, the _routine proceeds to step 108, where Q2 = _Qmin, and then at step 109, the port injection amount Q1 is made zero. FIG port injection Q1 as seen from routine 15 is reduced gradually adherent fuel amount Q _m to be stopped, it is in-cylinder injection amount Q2 since inflow amount Q _n also decreases gradually become Ban FIG 10 ( A).

On the other hand, referring to FIG.
In-cylinder injection quantity Q2 from the relationship shown in FIG. 7 (B) is calculated, then the port injection quantity Q by subtracting the in-cylinder injection amount Q2 from step 201 requests the total injection quantity Q _all
1 is calculated. Then the adherent fuel amount Q _m the following equation is calculated using the f ₂ (T _w) shown in FIG. 11, step 202.

Q _m = Q _m + Q 1 · f ₂ (T _w ) where Q 1 · f ₂ (T _w ) represents the amount of fuel adhesion between the previous interruption cycle and the current interruption cycle. Next, at step 203, the maximum value _Qmax of the attached fuel amount is calculated from the map shown in FIG. Then adherent fuel amount Q _m at step 204 whether or not greater than the maximum value Q _max is determined. When the Q _m ≧ Q _max is a Q _m = Q _max proceeds to step 205, the process proceeds to step 206. In step 206, the in-cylinder injection amount Q2 is calculated based on the following equation.

Q2 = Q2 + (Q_max−Q_mHere, (Q_max−Q_m) Indicates fuel within the port injection quantity Q1.
The amount of fuel that cannot flow into the firing chamber 5 is shown. This fuel
Charge (Q_max−Q_m) Gradually gets smaller and Q _m= Q
_maxWhen it becomes, it becomes zero. Therefore, the routine shown in FIG.
As can be seen, when port injection Q1 is started, the attached fuel
Quantity Q_mGradually increases, and accordingly (Q_max−
Q_m) Gradually decreases, so that the in-cylinder injection amount Q2
It will change as shown in (B).

On the other hand, referring to FIG.
In FIG. 7, the required total injection amount _Qall calculated from the relationship shown in FIG.
At 1, the in-cylinder injection amount Q2 is set to zero. Then step 3
02 In using f ₂ (T _w) shown in FIG. 11 adherent fuel amount Q _m is calculated from the following equation. _{Q m = Q m + Q1 ·} f 2 (T w) where Q1 · f ₂ (T _w) represents the fuel adhesion amount among the current interrupt cycle from the previous interrupt cycle. Next, at step 303, the maximum value _Qmax of the attached fuel amount is calculated from the map shown in FIG. Then adherent fuel amount Q _m at step 304 whether or not greater than the maximum value Q _max is determined. When the Q _m ≧ Q _max are Q _m = Q _max proceeds to step 205.

In the embodiment described so far, the second fuel injection valve 11b is provided for performing only the compression stroke injection. However, the second fuel injection valve 11b performs a part of the intake stroke injection. In this case, the method described so far can be applied.

[0032]

According to the present invention, it is possible to prevent the engine output torque from fluctuating when the fuel injection from the first fuel injection valve is started and stopped. Also, the first fuel injection valve
When the fuel injection is started, the amount of fuel injected from the first fuel injection valve is increased by the amount of fuel adhering to the inner wall surface of the intake passage.
If you choose to use the first fuel
When the fuel injection from the injection valve is stopped,
Charge continues to flow into the combustion chamber. This fuel is used throughout the combustion chamber
Formed by the fuel injected from the second fuel injection valve
A very lean mixture is formed around the mixed mixture. Only
However, the mixture is extremely lean and burns.
As a result, a large amount of unburned HC is emitted from the engine
become. However, in the present invention, the fuel is injected from the first fuel injection valve.
Fuel from the second fuel injection valve when fuel injection is started
The amount of fuel adhering is compensated for by the fuel, and the fuel injected from the first fuel injection valve
Since the amount of fuel injected is not increased, the fuel adhering to the inner wall of the intake passage
Is less. As a result, fuel injection from the first fuel injection valve
The amount of fuel flowing into the combustion chamber when
And thus the generation of unburned HC can be reduced.
Will be.

[Brief description of the drawings]

FIG. 1 is an overall view of an internal combustion engine.

FIG. 2 is a plan view of a piston.

FIG. 3 is a side sectional view of the internal combustion engine.

FIG. 4 is a side sectional view of the internal combustion engine.

FIG. 5 is a diagram showing a fuel injection amount and a fuel injection timing.

FIG. 6 is a diagram showing a required total injection amount _Qall .

FIG. 7 is a diagram showing a required total injection amount _Qall and an in-cylinder injection amount Q2.

FIG. 8 is a diagram showing Q _a and Q _b .

FIG. 9 is a side cross-sectional view of the internal combustion engine showing a time of fuel injection.

FIG. 10 is a time chart showing changes in in-cylinder injection amount Q2 and port injection amount Q1.

FIG. 11 is a diagram showing f ₂ (T _w ).

FIG. 12 is a diagram showing Q _max .

FIG. 13 is a diagram showing f (A _cc ) and f ₁ (T _w ).

FIG. 14 is a flowchart for executing fuel injection control.

FIG. 15 is a flowchart for executing fuel injection control.

FIG. 16 is a flowchart for executing fuel injection control.

FIG. 17 is a flowchart for executing fuel injection control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 ... Piston 5 ... Combustion chamber 10 ... Spark plug 11a ... 1st fuel injection valve 11b ... 2nd fuel injection valve

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02D 41/34 F02D 41/04 330

Claims (1)

(57) [Claims] An engine includes a first fuel injection valve for injecting fuel into an engine intake passage, and a second fuel injection valve for injecting fuel into an engine combustion chamber. When it is within a predetermined operating range, the fuel injection from the first fuel injection valve is stopped and the fuel injection from the second fuel injection valve is stopped.
The fuel is injected and the area around the spark plug is limited by this injected fuel.
An internal combustion engine that forms an air-fuel mixture only in the region where the fuel injection is performed and injects fuel from the first fuel injection valve when the operating state of the engine is out of the predetermined operating region.
The amount of fuel adhering to the inner wall surface of the intake passage is estimated when fuel injection from the first fuel injection valve is started, and flows into the engine combustion chamber when fuel injection from the first fuel injection valve is stopped. A means for estimating the amount of adhering fuel inflow,
When fuel injection from the first fuel injection valve is started, the second
The amount of adhered fuel is compensated for by the injected fuel from the fuel injector
Cormorants with fuel injection internal combustion engine the fuel injection amount from the second fuel injection valves to lose weight by the inflow amount <br/> when fuel injection from the first fuel injection valve is stopped.