JP2003161178A - Fuel injection control method for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection control method for an internal combustion engine suppressing the generation amount of soot. <P>SOLUTION: A diesel engine 10 is provided with a main fuel injection valve 17 for injecting a main fuel, and a secondary fuel injection valve 18 for injecting a secondary fuel which is smaller in soot generation amount than the main fuel. An ECU 30 calculates the injection amount of the main fuel in response to engine load. When the injection time of the main fuel corresponding to the injection amount calculated by the ECU 30 exceeds a predetermined one, the main fuel injection by the injection valve 17 is stopped, and the secondary fuel in the amount corresponding to that of the main fuel to be injected after the predetermined time elapse is injected through the injection valve 18. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fuel injection control method for an internal combustion engine.

[0002]

2. Description of the Related Art In an internal combustion engine for injecting fuel directly into a cylinder, particularly a diesel engine, an injector disposed above a combustion chamber 6 of a cylinder 1 is generally shown in FIG. Fuel is injected from 5 into the concave cavity 4 formed in the top surface 3 of the piston 2.

At the time of high load of such a direct injection type diesel engine, the fuel injection amount becomes large and the injection period becomes long. At this time, as shown in FIG. 6 (a), the fuel injected when the injection period is extended and the piston 2 is located below in the latter stage of injection does not fit inside the cavity 4, and a part thereof is It will scatter on the top surface 3 of 2 and will hit the peripheral wall of the cylinder 1. In addition, FIG.
Further, as shown in (b), the fuel injected in the latter stage of injection is directly applied to the peripheral wall of the cylinder 1. In such a case, the combustion of the diesel engine is likely to be incomplete, and the amount of suit produced increases. Since this suit has a high chance of coming into direct contact with the engine oil on the peripheral wall of the cylinder 1, the amount of the suit mixed in the engine oil increases significantly, which adversely affects the lubricity thereof.

The present invention has been made in view of such circumstances, and an object thereof is to provide a fuel injection control method for an internal combustion engine capable of suppressing the amount of suit generation.

[0005]

[Means for Solving the Problems] Means for achieving the above-mentioned objects and their effects will be described below. The invention according to claim 1 calculates the injection amount of the main fuel according to the engine load, directly injects the calculated amount of the main fuel into the cylinder, and changes the injection of the main fuel according to the progress of combustion. A fuel injection control method for an internal combustion engine, wherein when main fuel injection according to the calculated injection amount extends after a predetermined time, injection of the main fuel after the predetermined time is performed. And the sub-fuel having a smaller suit generation amount than the main fuel in an amount corresponding to the injection amount of the main fuel after the predetermined time is injected at least from the latter stage of the injection timing of the main fuel. Is characterized by.

In an internal combustion engine that directly injects a main fuel in an injection amount according to the engine load into a cylinder, when injecting a main fuel in an injection amount according to the engine load, the injection of the main fuel extends after a predetermined time. In that case, the amount of suits generated increases.
In this regard, according to the first aspect, the injection of the main fuel after the predetermined time is stopped, and the amount of suit generated is smaller than that of the main fuel in an amount corresponding to the injection amount of the main fuel after the predetermined time. The fuel is injected at least from the latter stage of the injection timing of the main fuel. Therefore, it is possible to suppress the amount of suit generation while obtaining an output that satisfies the engine load.

According to a second aspect of the present invention, in the first aspect, the predetermined time is a time when the fuel injected by the main fuel is scattered from the top surface of the piston. When the injected fuel from the main fuel is scattered from the top surface of the piston, combustion of the internal combustion engine is incomplete and the amount of suit generated increases. According to the above configuration, the injection of the main fuel is stopped at this time, and the sub fuel having a smaller suit generation amount than the main fuel is injected, so that the suit generation amount can be suppressed.

The invention described in claim 3 is the invention according to claim 1 or 2.
In the above, the injection of the sub fuel is completed at an injection end timing when the injection is performed using only the main fuel. If the injection of the auxiliary fuel is continued until after the injection end timing when the injection is performed with only the main fuel, the combustion may be deteriorated and the output may be reduced and the fuel efficiency may be deteriorated. In this regard, according to the above configuration, the injection of the auxiliary fuel is completed at the injection end timing when the injection is performed with only the main fuel, so that the suitability is reduced while suppressing the output reduction and the deterioration of fuel efficiency. Can be suppressed.

In a fourth aspect of the present invention, in any one of the first to third aspects, the main fuel is a liquid at room temperature and atmospheric pressure, the auxiliary fuel is a gas at room temperature and atmospheric pressure, and the internal combustion engine is A fuel injection valve for a main fuel that injects the main fuel and a fuel injection valve for a sub fuel that injects the sub fuel are provided.

By providing the main fuel injection valve for injecting the main fuel and the sub fuel injection valve for injecting the sub fuel as described above, the main fuel is liquid at room temperature and normal pressure,
It can be embodied in an internal combustion engine in which the auxiliary fuel is gas at room temperature and pressure.

According to a fifth aspect of the present invention, in any one of the first to third aspects, the main fuel is a liquid at room temperature and atmospheric pressure, the auxiliary fuel is a liquid at room temperature and atmospheric pressure, and the internal combustion engine is A fuel injection valve capable of injecting a mixture of the main fuel and the sub fuel is provided.

By providing the fuel injection valve capable of mixing and injecting the main fuel and the auxiliary fuel in this way, the internal fuel engine which makes the main fuel liquid at room temperature and atmospheric pressure and the auxiliary fuel liquid at room temperature and atmospheric pressure It is possible to reduce the number of fuel injection valves and suppress an increase in cost.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the internal combustion engine is a diesel engine and the main fuel is light oil. In a diesel engine that uses light oil as the main fuel, if the light oil spray is scattered from the top surface of the piston, combustion tends to be incomplete, and the amount of suits increases,
This control is extremely useful in diesel engines.

The invention according to claim 7 is characterized in that, in any one of claims 1 to 6, the auxiliary fuel is an oxygen-containing fuel. According to this configuration, the oxygen-containing fuel does not have a direct bond between carbon and carbon, so that the production of acetylene, which is a precursor of soot generation, is small, so almost no soot is generated and the fuel injection period of the internal combustion engine becomes long. Even so, it is possible to suppress the amount of suits generated.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A first embodiment of the fuel injection control device for a diesel engine according to the present invention will be described below with reference to FIGS.

The diesel engine of this embodiment is a direct injection type vehicle-mounted diesel engine that directly injects fuel into a cylinder. FIG. 1 shows a schematic configuration of a fuel injection control device and a diesel engine to which the fuel injection control device is applied, a hydraulic circuit configuration of a lubricating system of the engine, and the like in the present embodiment.

First, the structure of the diesel engine will be described with reference to FIG. Diesel engine 1
0 is configured to include an intake passage 11, an exhaust passage 12, a combustion chamber 16 and the like. Diesel engine 1
A piston 14 is disposed in each cylinder 0 of 0 so as to be vertically movable. At the center of the top surface 14a of the piston 14,
A “cavity” (cavity) 15 that forms the combustion chamber 16 is formed. And above the combustion chamber 16,
Fuel injection valve 17 for main fuel for injecting light oil as main fuel
And a fuel injection valve 18 for a sub fuel for injecting an oxygen-containing fuel as a sub fuel. In this embodiment, dimethyl ether, which is a gas at normal temperature and pressure, is adopted as the oxygen-containing fuel. Since dimethyl ether does not form acetylene, which is a precursor of soot generation, because there is no direct carbon-carbon bond, soot generation is almost non-existent.

In operating the diesel engine 10, first, the main fuel (light oil) stored in the fuel tank 19 is stored.
Is pumped out by the main fuel pump 20, pressurized to a high pressure, and applied to the main fuel injection valve 17 of each cylinder 13. A nozzle (not shown) is provided at the tip of the fuel injection valve 17 for the main fuel to open the valve when its back pressure reaches a predetermined high pressure and inject fuel. An electromagnetic solenoid (not shown) provided inside the fuel injection valve 17 for the main fuel controls the back pressure of the nozzle to determine the start and end of fuel injection.

The auxiliary fuel (dimethyl ether) stored in the fuel tank 21 is pumped out by the auxiliary fuel pump 22, pressurized to a high pressure, and applied to the auxiliary fuel injection valve 18 of each cylinder 13. There is. A nozzle (not shown) is provided at the tip of the fuel injection valve 18 for the auxiliary fuel, which opens when the back pressure of the fuel injection valve 18 becomes a predetermined high pressure and injects the fuel. Then, the back pressure of the nozzle is controlled by an electromagnetic solenoid (not shown) provided inside the fuel injection valve 18 for the sub fuel, so that the start and the end of the fuel injection are determined.

On the other hand, on the upstream side of the intake passage 11, an intake throttle valve 24 is provided which is opened and closed by a step motor 23 to change the passage area of the intake passage 11. Further upstream thereof, an air flow meter 2 for detecting the amount of intake air flowing through the intake passage 11.
5 and an air cleaner 26 for purifying the intake air are respectively provided.

On the other hand, in the diesel engine 10 and the fuel injection control device for the diesel engine 10, the outputs of various sensors such as the air flow meter 25 serve as a control system for the engine 10 and a diagnostic system for the electronic control device ( “ECU”) 30. This EC
A U30 is a step motor 23 that drives the intake throttle valve 24 to open and close, and a fuel injection valve 1 for main fuel that performs fuel injection.
7, the sub fuel injection valve 18, the main fuel pump 20, the sub fuel pump 22 and the like are driven and controlled.

In addition to the air flow meter 25, the ECU 30 includes an NE sensor 27 for detecting the rotational phase and rotational speed of the crankshaft 27a of the diesel engine 10, an accelerator sensor 28 for detecting the depression amount of the accelerator pedal 28a, and the like. The outputs of various sensors that detect the engine load are input. Then, the ECU 30 grasps the operating state of the diesel engine 10 based on the output results of these sensors, and drives various actuators including the fuel injection valve 17 for the main fuel, the fuel injection valve 18 for the auxiliary fuel and the step motor 23. Control the same engine 10
Execute various controls of.

As a part of such engine control, the ECU
The control unit 30 controls the fuel injection amount and the fuel injection timing based on the drive control of the main fuel injection valve 17 and the sub fuel injection valve 18. Next, such fuel injection amount and fuel injection timing control will be described.

First, the ECU 30 determines, based on the output results of various sensors such as the NE sensor 27 and the accelerator sensor 28, the fuel injection amount qfin and fuel injection timing (fuel injection timing) of the main fuel (light oil) according to the operating state of the diesel engine 10. The injection start timing) tfst is calculated. Also, E
The CU 30 calculates the fuel injection time in which the fuel can be injected according to the fuel injection amount qfin calculated in this way, based on the engine rotation speed detected by the NE sensor 27, and the fuel injection timing (fuel injection end timing). tfend
To calculate. Further, the ECU 30 uses the fuel injection valve 1 for the main fuel
The fuel injected by the main fuel (light oil) from 7 is the piston 14
The predetermined time tltd of scattering from the top surface 14a of the is calculated. As shown in FIG. 4, the main fuel (light oil) is injected by the main fuel injection valve 17 at a predetermined timing tlt.
If d or less, the amount of suit generation is small. This is because the main fuel (light oil) is the cavity 15 of the piston 14.
This is because the main fuel (light oil) is satisfactorily combusted in the combustion chamber 16 because it is contained inside, and the amount of suit produced is suppressed. Further, when the injection of the main fuel (light oil) by the fuel injection valve 17 for the main fuel exceeds the predetermined timing tltd,
The amount of suits generated is increasing. The main fuel (light oil) depends on the position of the piston 14 at that time and the cavity 15
This is because the fuel does not fit inside and scatters from the top surface 14a of the piston 14, and the combustion of the main fuel (light oil) in the combustion chamber 16 is incomplete, and the amount of suit generated increases.

Therefore, in this embodiment, as shown in FIG. 3 (a), if the injection end timing tfend is equal to or shorter than the predetermined timing tltd, the main fuel (light oil) can be stored in the cavity 15 of the piston 14, and the main fuel The main fuel injection valve 17 only injects the main fuel (light oil). At this time,
Since the main fuel (light oil) fits inside the cavity 15 of the piston 14, the main fuel (light oil) is satisfactorily burned in the combustion chamber 16 and the amount of suits generated is suppressed.

Further, as shown in FIG. 3B, when the injection end timing tfend exceeds the predetermined timing tltd, the main fuel (light oil) becomes the piston 14 after the predetermined timing tltd.
Cannot fit inside the cavity 15. In this case, the combustion of the main fuel (light oil) in the combustion chamber 16 is incomplete, and the amount of soot generated increases. Therefore, the ECU 3
0 executes the injection of the main fuel (light oil) by the fuel injection valve 17 for the main fuel during the period from the injection start timing tfst to the predetermined timing tltd. Then, the ECU 30 stops the injection of the main fuel (light oil) by the main fuel injection valve 17 at the predetermined time tltd. The injection amount of the main fuel (light oil) at this time is qfin * (tltd-tfst) /
(Tfend-tfst).

The ECU 30 calculates the injection amount of the auxiliary fuel (dimethyl ether) corresponding to the heat generation amount of the injection amount of the main fuel after the predetermined time tltd. The density of dimethyl ether is 0.66 g / cm ³ , and the lower heating value is 2.
It is 7.6 megajoules / kg. On the other hand, the density of light oil is 0.84 g / cm ³ , and the lower heating value is 42.5.
It is megajoule / kg. Therefore, dimethyl ether equivalent to 1 mm ³ of light oil is about 2 mm ³ {= 1 × (42.5 / 2
7.6) × (0.84 / 0.66)}. ECU3
0 is the fuel injection valve 17 for the main fuel and the fuel injection valve 1 for the auxiliary fuel
The injection time for the sub fuel injection valve 18 to inject the sub fuel corresponding to the main fuel is calculated based on the ratio of the fuel injection amount per unit time of 8. If the fuel injection amount of the main fuel injection valve 17 and the auxiliary fuel injection valve 18 are the same, the auxiliary fuel injection valve 18 injects the auxiliary fuel corresponding to the main fuel. Requires an injection time that is twice as long as the injection time of the main fuel injection valve 17.
Therefore, the injection amount of the auxiliary fuel (dimethyl ether) at this time is 2 * qfin * (tltd-tfst) / (tf
end-tfst). Then, the ECU 30 sets the injection start timing of the sub fuel (dimethyl ether) to (2 * tltd-tfend) so as to be completed at the injection end timing tfend when the injection is performed only with the main fuel.

In this diesel engine 10,
By performing the fuel injection control and the intake air amount control as well, the emission and the fuel consumption are improved. Therefore, the intake throttle valve 24 driven by the step motor 23 capable of finely adjusting the opening degree is provided in the intake passage 11 as described above, and the intake air amount is detected by the air flow meter 25.
Then, the ECU 30 drives and controls the step motor 23 according to the engine operating state to perform fine intake air amount control.

On the other hand, the ECU 30 controls the inside of the combustion chamber 16 based on the fuel injection amount calculated for controlling the drive of the main fuel injection valve 17 and the intake air amount detected by the air flow meter 25. The air-fuel ratio of is calculated.

FIG. 2 is a flow chart showing the "fuel injection control process" used in this embodiment. This process is periodically executed by the ECU 30 (FIG. 1) every predetermined calculation period.

Now, when the processing shifts to this routine, E
First, in step 102, the CU 30 calculates the fuel injection amount qfin according to the engine load. Further, in the subsequent step 104, the ECU 30 causes the ECU 30 to operate as shown in FIGS.
As shown in, the injection start timing tfst and the injection end timing tfend using only the main fuel are calculated.

Then, in the following step 106,
The ECU 30 determines that the injection end timing tfend is the predetermined timing tlt.
It is determined whether or not d or less. If the injection end timing tfend is equal to or less than the predetermined timing tltd as shown in FIG. 3A, the process proceeds to step 108, and the injection end timing t
As shown in FIG. 3B, the fend is a predetermined time tlt.
If d is exceeded, the process proceeds to step 110.

In step 108, the ECU 30 operates the main fuel pump 20 and the main fuel injection valve 17, causes only the main fuel (light oil) to be injected, and ends this processing.

In step 110, the ECU 3
0 operates the main fuel pump 20 and the main fuel injection valve 17 to inject the main fuel (light oil), and operates the sub fuel pump 22 and the sub fuel fuel injection valve 18 to operate the sub fuel. (Dimethyl ether) is injected, and this processing is once terminated.

According to this embodiment described above, the following effects can be obtained. (1) In this embodiment, when injecting the main fuel (light oil) in an injection amount according to the engine load of the diesel engine 10, the injection of the main fuel is stopped after the predetermined time tltd, and the suit generation amount is changed at least after that. I try to inject almost no secondary fuel. Therefore, even when the diesel engine 10 with a large fuel injection amount has a high load, it is possible to suppress the amount of suit generation while obtaining an output that satisfies the engine load.

(2) In this embodiment, the injection by the auxiliary fuel is the injection end timing t when the injection is performed only by the main fuel.
Since the process is completed at the end, the amount of suit generated can be suppressed while suppressing the output reduction of the diesel engine 10 and the deterioration of fuel efficiency.

(3) In a diesel engine that uses light oil as the main fuel, combustion is likely to be incomplete and a suit is likely to occur, so this embodiment of injecting the sub fuel is extremely useful.

(4) In the present embodiment, since the auxiliary fuel is an oxygen-containing fuel in which carbon is not directly bonded to carbon, acetylene, which is a precursor for soot generation, is not produced, and so sotes are hardly produced. Therefore, even if the fuel injection amount of the diesel engine 10 increases and the fuel injection period becomes long, the suit generation amount can be suppressed well.

(5) In this embodiment, the main fuel injection valve 17 for injecting the main fuel and the sub fuel injection valve 18 for injecting the sub fuel are provided, so that the main fuel is kept at room temperature and normal pressure. It can be embodied in the diesel engine 10 in which the liquid is liquid and the auxiliary fuel is gas at normal temperature and pressure.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. In order to avoid redundant description, the same elements as those described in FIG. 1 are designated by the same reference numerals.

In this embodiment, only the fuel injection valve 17 is provided above each combustion chamber 16 of the diesel engine 10 and the auxiliary fuel injection valve 18 is omitted.
In the present embodiment, the fuel tank 32 stores oxygen-containing fuel that is liquid at room temperature and pressure. As the oxygen-containing fuel which is liquid at normal temperature and pressure, dimethoxymethane, ethylene glycol-dimethyl ether, diethylene glycol-dimethyl ether, diethylene glycol-diethyl ether, butyl ether and the like can be adopted.
Further, methyl alcohol, ethyl alcohol, propyl alcohol, or the like can be adopted as the oxygen-containing fuel that is liquid at normal temperature and pressure. These oxygen-containing fuels also produce less suiting because acetylene, which is a precursor for sooting, is less produced.

There is no oxygen-containing fuel that is gaseous at room temperature and normal pressure except dimethyl ether described in the first embodiment. Therefore, in the present embodiment, a fuel injection control device for a diesel engine that injects an oxygen-containing fuel that is liquid at room temperature and normal pressure as an auxiliary fuel will be described.

A switching valve 34 is provided between the main fuel pump 20 for pumping out the main fuel (light oil) from the fuel tank 19 and the fuel injection valve 17, and the fuel tank 3
A switching valve 35 is provided between the fuel injection valve 17 and the sub fuel pump 33 that pumps the sub fuel (oxygen-containing fuel) from the fuel cell 2. The switching valves 34 and 35 are the ECU 3
Switching control is performed by 0.

When the diesel engine 10 is operated, the ECU 30 calculates the fuel injection amount qfin, the injection start timing tfst, and the injection end timing tfend of the main fuel (light oil) according to the load of the diesel engine 10. This injection end timing tfend is the predetermined timing t
If it is less than or equal to ltd, the main fuel pump 20, the switching valve 34, and the fuel injection valve 17 are operated. As a result, the main fuel (light oil) stored in the fuel tank 19 is pumped out by the main fuel pump 20, and is supplied to the fuel injection valve 17 of each cylinder 13 via the opened switching valve 34 to supply the main fuel ( Injection is performed using only light oil).

Further, the injection end timing tf of the fuel injection amount qfin calculated according to the load of the diesel engine 10
If the end exceeds the predetermined time tltd, the main fuel (light oil) becomes the piston 1 after the predetermined time tltd.
4 will not fit inside the cavity 15. In this case, the combustion of the main fuel (light oil) in the combustion chamber 16 is incomplete, and the amount of soot generated increases. Therefore, the ECU 3
In 0, during the period from the injection start timing tfst to the predetermined timing tltd, the main fuel pump 20 and the switching valve 34 are operated to supply the main fuel to the fuel injection valve 17 and execute the injection with the main fuel (light oil). Main fuel pump 2
In the latter stage of the injection timing of the main fuel based on the operation of 0 and the switching valve 34, the sub fuel pump 33 and the switching valve 35 are operated. As a result, the auxiliary fuel (oxygen-containing fuel) stored in the fuel tank 32 is stored in the auxiliary fuel pump 3
Switching valve 35 pumped by 3 and opened
Is supplied to the fuel injection valve 17 of each cylinder 13 through, and the auxiliary fuel (oxygen-containing fuel) is mixed with the main fuel (light oil) and injected.

Then, the ECU 30 stops the operation of the main fuel pump 20 and the switching valve 34 at a predetermined time tltd to stop the supply of the main fuel to the fuel injection valve 17. Therefore, based on the operation of the sub fuel pump 33 and the switching valve 35, injection is performed using only the sub fuel (light oil).

According to this embodiment described above, the following effects can be obtained in addition to the effects (1) to (4) of the first embodiment. (6) In the present embodiment, by providing the fuel injection valve 17 that can mix and inject the main fuel and the sub fuel, the main fuel is a liquid at room temperature and atmospheric pressure, and the sub fuel is a liquid at room temperature and atmospheric pressure. It can be embodied in the engine 10. Further, since the main fuel and the sub fuel can both be liquid at room temperature and normal pressure, a common fuel injection valve can be used for the main fuel and the sub fuel, and the fuel injection valve 1
It is possible to reduce the number of 7 and suppress an increase in cost.

The embodiment is not limited to the above, but may be modified as follows. In the second embodiment described above, by providing the fuel injection valve 17 that can inject the main fuel and the sub fuel by mixing them,
It may be embodied in an internal combustion engine in which the main fuel and the sub fuel are gas at normal temperature and pressure.

In each of the above embodiments, the direct injection type diesel engine using light oil as the main fuel is applied, but gasoline, liquefied natural gas (LNG), liquefied petroleum gas (LPG) or the like is used as the main fuel in the cylinder. It can also be applied to an internal combustion engine that directly injects. In this case as well, it is possible to obtain the above-described embodiment or effects similar thereto.

In each of the above embodiments, the oxygen-containing fuel was used as the auxiliary fuel, but a liquid fuel (GTL) in which methane gas is synthesized by the Fischer-Tropsch method may be used as the auxiliary fuel. It can be applied to the diesel engine 10 including the common rail system as the fuel injection control device of each of the above embodiments. Also in that case, it is possible to obtain substantially the same effects as those of the above embodiments.

Next, other technical ideas that can be understood from the above-described embodiments will be described below. -In any one of Claims 1-3, the said main fuel is gas at normal temperature and normal pressure, the said oxygen-containing fuel is gas at normal temperature and normal pressure, and the said internal combustion engine mixes the said main fuel and the said oxygen-containing fuel. Injection control method for an internal combustion engine having a fuel injection valve capable of injecting fuel by a direct injection method.

[Brief description of drawings]

FIG. 1 is a schematic diagram schematically showing the overall structure of a first embodiment of a fuel injection control device for a diesel engine according to the present invention.

FIG. 2 is a flowchart showing a processing procedure of fuel injection control according to the same embodiment. Fig.

FIG. 3 is an explanatory diagram showing a relationship between an engine load and an injection mode in the same embodiment.

FIG. 4 is an explanatory diagram showing the relationship between the injection end timing and the amount of suit generation when only the main fuel is injected.

FIG. 5 is a schematic diagram schematically showing the overall structure of a second embodiment of the fuel injection control device for a diesel engine according to the present invention.

FIG. 6 is a cross-sectional view showing a fuel injection mode in a direct injection type diesel engine.

[Explanation of symbols]

10 ... Diesel engine, 14 ... Piston, 15 ... Cavity, 16 ... Combustion chamber, 17 ... (Main fuel) fuel injection valve, 18 ... Sub fuel fuel injection valve, 23 ... Step motor, 24 ... Intake throttle valve, 25 … Air flow meter, 27
... NE sensor, 30 ... Electronic control unit (ECU), 34,
35 ... Switching valve.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 41/40 F02D 41/40 D F02M 25/00 F02M 25/00 H K N 37/00 341 37/00 341D 341Z 43/04 43/04 61/04 61/04 G 61/14 310 61/14 310U // C10L 1/02 C10L 1/02 1/08 1/08 1/18 1/18 C F term (reference) ) 3G023 AA04 AB05 AC05 AC06 AC07 AC08 AD12 AF01 3G066 AA07 AB02 AB04 AB05 AB06 AD12 BA24 CC01 CD26 DA04 DC04 DC05 DC09 DC11 3G092 AA02 AB03 AB05 AB06 AB11 AB12 AB14 BA01 BA04 BB05 BB06 BB20 DC03 DE03SEA14 FA01B14 BB05 AC06 AC07 AC08 AD12 AF01 3G066 HB05X HE01Z HF08Z 3G301 HA02 HA22 HA23 HA24 JA21 JA26 KA06 KA09 LA03 LB11 LC01 LC04 MA01 MA11 NA08 NC02 NE17 PB03A PB05A PE01Z PF03Z 4H013 BA00 BA03

Claims (7)

[Claims] 1. A main fuel injection amount is calculated according to an engine load, the calculated amount of main fuel is directly injected into a cylinder, and the main fuel injection is continued according to the progress of combustion. A method for controlling fuel injection of an internal combustion engine, wherein when the injection of the main fuel according to the calculated injection amount extends after a predetermined time, the injection of the main fuel after the predetermined time is stopped. A fuel injection of an internal combustion engine in which an amount of sub fuel having a smaller amount of suit generation than the main fuel corresponding to the injection amount of the main fuel after the predetermined time is injected at least from the latter stage of the injection time of the main fuel. Control method. 2. The fuel injection control method for an internal combustion engine according to claim 1, wherein the predetermined time is a time when the fuel injected by the main fuel scatters from the top surface of the piston. 3. The fuel injection control method for an internal combustion engine according to claim 1 or 2, wherein the injection of the sub fuel is completed at an injection end timing when the injection is performed using only the main fuel. 4. The main fuel according to claim 1, wherein the main fuel is a liquid at room temperature and atmospheric pressure, the auxiliary fuel is a gas at room temperature and atmospheric pressure, and the internal combustion engine is a main fuel injector that injects the main fuel. A fuel injection control method for an internal combustion engine, comprising: a fuel injection valve for fuel; and a fuel injection valve for auxiliary fuel for injecting the auxiliary fuel. 5. The main fuel according to any one of claims 1 to 3, wherein the main fuel is a liquid at room temperature and normal pressure, the sub fuel is a liquid at room temperature and normal pressure, and the internal combustion engine is the main fuel and the sub fuel. Injection control method for an internal combustion engine having a fuel injection valve capable of injecting mixed fuel. 6. The fuel injection control method according to claim 1, wherein the internal combustion engine is a diesel engine and the main fuel is light oil. 7. The fuel injection control method according to claim 1, wherein the sub fuel is an oxygen-containing fuel.