JP4462032B2 - Fuel injection control device for internal combustion engine - Google Patents

Description

  The present invention relates to a fuel injection control device for an internal combustion engine suitable for use in a vehicle.

Conventionally, the indicated mean effective pressure is calculated based on the in-cylinder pressure and the crank angle during engine warm-up, and the engine air-fuel ratio is corrected so that the indicated indicated mean effective pressure is equal to the reference pressure value. By doing so, there is a technique aimed at improving the fuel consumption and exhaust gas performance of the engine during the warm-up operation (see, for example, Patent Document 1 below).
JP-A 64-73147

However, according to the technique of Patent Document 1, since calculation for obtaining the indicated mean effective pressure is required, there is a problem that the control must be complicated.
Furthermore, according to the technique of Patent Document 1, based on the determination whether the indicated mean effective pressure obtained based on the in-cylinder pressure of the engine and the crank angle of the engine is higher or lower than a preset reference pressure. Therefore, for example, even when the difference between the indicated mean effective pressure and the reference pressure is very small, the air-fuel ratio is corrected, and control stability and engine combustion are controlled. There is also a problem that the stability becomes insufficient.

  The present invention has been devised in view of such problems, and provides a fuel injection control device for an internal combustion engine capable of improving exhaust gas performance while ensuring startability of the internal combustion engine and combustion stability immediately after the start. The purpose is to do.

To achieve the above object, a fuel injection control device for an internal combustion engine according to the present invention (Claim 1) includes a fuel injection device for supplying fuel to the internal combustion engine, a temperature detection means for detecting the temperature of the internal combustion engine, Basic start injection that sets a basic start injection amount, which is the amount of fuel injected every cycle during the elapse of a predetermined period from the start of the internal combustion engine, in accordance with the internal combustion engine temperature detected by the temperature detection means Amount setting means, target peak in-cylinder pressure setting means for setting a target peak in-cylinder pressure of the in-cylinder pressure for each combustion stroke during the predetermined period according to the internal combustion engine temperature, and in-cylinder pressure for detecting the in-cylinder pressure of the internal combustion engine A detection means, an actual peak in-cylinder pressure that is the maximum pressure in the in-cylinder pressure detected by the in-cylinder pressure detection means, and a predetermined target peak in-cylinder pressure set by the target peak output setting means. Correction means for calculating the difference for each combustion stroke, and correcting the basic starting injection amount so that the difference decreases when the average of the calculated differences for each combustion stroke is equal to or greater than a predetermined value; Therefore , the injection amount correction means is such that the difference for each combustion stroke is all positive, that is, the actual peak in-cylinder pressure is always higher than the target peak in-cylinder pressure during the predetermined period, and the difference for each combustion stroke. When the average is equal to or greater than a predetermined value, the basic start injection amount is corrected so as to reduce the difference by subtracting the basic starting injection amount, and the difference for each combustion stroke is all negative, that is, during the predetermined period. When the actual peak in-cylinder pressure is always lower than the target peak in-cylinder pressure and the average of the differences for each combustion stroke is equal to or greater than a predetermined value, the difference decreases by adding the basic start injection amount; So that the difference between combustion strokes is not all positive or all If non-negative is characterized in that not corrected the basic starting injection quantity.

According to the fuel injection control device for an internal combustion engine of the present invention, the average difference between the actual peak in-cylinder pressure and the target peak in-cylinder pressure calculated for each combustion stroke during a predetermined period after the start of the internal combustion engine is predetermined. When the value is equal to or greater than the value, the basic starting injection amount is corrected, so that the exhaust gas performance can be improved while ensuring the startability of the internal combustion engine and the combustion stability immediately after the start .
Also, the difference between the actual peak cylinder pressure and the target peak cylinder pressure of the in-cylinder pressure that is calculated for each combustion stroke during a predetermined period after the start of the engine, all are positive or negative, and, of the difference in the If the average is equal to or greater than the predetermined value, the basic starting injection amount is corrected. If the differences between the combustion strokes are not all positive or all negative, the basic starting injection amount is not corrected. Thus, while avoiding the situation where the correction is performed, the control stability can be improved and the exhaust gas performance can be improved. (Claim 1 )

  Hereinafter, a fuel injection control device for an internal combustion engine according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration, and FIGS. 2 and 3 are for obtaining an actual peak value of in-cylinder pressure. 4 is a flowchart showing the basic starting injection amount correction control. FIGS. 5 and 6 are schematic graphs showing the relationship among the actual peak in-cylinder pressure, the target peak in-cylinder pressure, and the combustion stroke. .

As shown in FIG. 1, a vehicle 1 is equipped with a gasoline engine (an internal combustion engine; hereinafter simply referred to as “engine”) 2, and an intake system 3 is provided on the intake side of the engine 2. An exhaust system 4 is provided on the exhaust side.
The intake system 3 includes an air cleaner (A / C) 5, an air flow sensor (AFS; fresh air amount detection means) 6, and a throttle valve 7.

The engine 2 includes a water temperature sensor 12, an engine speed sensor 13, an exhaust cam angle sensor 15, a crank angle sensor 16, an in-cylinder pressure sensor 17, and an injector (fuel injection device) 18.
The air cleaner 5 is provided at the intake port of the intake passage 14 and filters fresh air taken into the intake system 3.

The air flow sensor 6 is disposed upstream of the throttle valve 7 in the intake passage 14 and detects a flow rate Q _{FR of} fresh air flowing into the intake passage 14. The detection result by the air flow sensor 5 is read by the ECU 20 described later in a timely manner.
The throttle valve 7 is provided in the intake passage 14 and adjusts the fresh air flow rate Q _FR supplied to the engine 2 by adjusting the opening degree θ _TH thereof.

Water temperature sensor 12 is a sensor for detecting a cooling water temperature T _W of the engine 2, the detection result is adapted to be read timely by later-described ECU 20.
The engine speed sensor 13 detects the speed Ne of the engine 2 and the detection result is read by the ECU 20 described later in a timely manner.
The injector 18 injects fuel into an intake port (not shown) of the engine 2 based on a fuel injection signal I _NJ from the ECU 20. The fuel injection signal I _NJ corresponds to a basic starting injection amount Q _IJ set by a basic starting injection amount setting unit 51 of the ECU 20 described later or a basic starting injection amount Q _IJ-C corrected by a correcting unit 53. To be set.

Exhaust cam angle sensor 15 is for detecting the cam angle theta _CAM the exhaust side cam angle theta _CAM of the detected exhaust side here is adapted to be read by timely ECU 20.
The crank angle sensor 16 detects a crankshaft angle (crank angle) θ _CNK, and the detected crank angle θ _CNK is read by the ECU 20 in a timely manner.

The in-cylinder pressure sensor 17 detects the pressure in the cylinder (that is, the in-cylinder pressure) Pe, and the actual in-cylinder pressure Pe _-A that is the in-cylinder pressure actually detected by the in-cylinder pressure sensor 17 is detected by the ECU 20. It is supposed to be read. In the present embodiment, the ECU 20 reads the actual in-cylinder pressure Pe _-A detected by the in-cylinder pressure sensor 17 a plurality of times during one combustion stroke. Further, although described later in detail, the maximum pressure among a plurality of actual in-cylinder pressures Pe _−A obtained in one combustion stroke is referred to as “actual peak in-cylinder pressure Pe _max-A ”. Then, the actual in-cylinder pressure Pe _-A detected by the in-cylinder pressure sensor 17 and read by the ECU 20 is then sequentially and individually stored in an actual in-cylinder pressure storage area M ₁ (described later) in the memory 55 in the ECU 20. It has become so.

The engine 2 is a four-cylinder engine, and the in-cylinder pressure sensor 17 is also provided in each of the four cylinders. In the present embodiment, description will be given focusing on one of the four cylinders. .
The vehicle 1 is provided with an electronic control unit (ECU; control means) 20 including an interface unit, a CPU, a timer (all not shown), a memory 55 and the like. Further, the ECU 20 includes, as software, a basic starting injection amount setting unit (basic starting injection amount setting unit) 51, a target peak in-cylinder pressure setting unit (target peak in-cylinder pressure setting unit) 52, and a correcting unit (correcting unit). 53 and a stroke number counter 54 are provided.

The memory 55 within the actual cylinder pressure storage area M _1, the actual peak cylinder pressure storage area M _2, and the target peak cylinder pressure storage area M _3, are respectively set and the basic starting injection amount storing area M ₄ ing.
Among these, the basic start injection amount setting unit 51 uses a basic start injection amount Q _IJ , which is a predetermined amount of fuel injected from the injector 18, as the coolant temperature T of the engine 2 detected by the water temperature sensor 12. It is set according to _W.

The basic start injection amount setting unit 51 starts the engine 2 based on the fact that an ignition switch (not shown) is turned on (that is, power is supplied to a cell motor (not shown)). This is determined, and a timer (not shown) built in the ECU 20 is operated to measure the time t from the start of the engine 2.
Further, the basic starting injection amount setting unit 51 reads the actual in-cylinder pressure Pe- _A detected by the in-cylinder pressure sensor 17 when it is determined by the stroke number counter 54 of the ECU 20 described later that the combustion stroke has started. Thus, it is stored in the actual cylinder pressure storage area M ₁ in the memory 55. Incidentally, according to the basic starting injection quantity setting unit 51, store and load the actual in-cylinder pressure Pe _-A, the actual in-cylinder pressure storage area M ₁ of the read actual cylinder pressure Pe _-A is detected by the crank angle sensor 16 Until the determined crank angle θ _CNK reaches 540 degrees and it is determined that the combustion stroke is completed, the process is repeatedly executed in a very short cycle.

The target peak in-cylinder pressure setting unit 52 stores the target peak in-cylinder pressure storage area M ₃ of the memory 55 in accordance with the coolant temperature T _W of the engine 2 detected by the water temperature sensor 12 (that is, the temperature of the engine 2). The target peak in-cylinder pressure Pe _max-T for each combustion stroke is acquired from the target peak in-cylinder pressure map (not shown).
The target peak in-cylinder pressure Pe _max-T reduces the amount of harmful components such as HC (hydrocarbon), NOx (nitrogen oxide), CO (carbon monoxide) contained in the exhaust gas discharged from the engine 2. In this embodiment, the target peak in-cylinder pressure Pe _max-T is set particularly for the purpose of reducing the amount of HC.

In order to set the target peak in-cylinder pressure Pe _max-T in order to reduce the amount of HC contained in the exhaust gas, fuel adhered to a cylinder liner (not shown), a piston (not shown), or a clevis (not shown) in the combustion chamber. It is necessary to consider that the fuel remaining in the abbreviation) is discharged from the engine 2 together with the exhaust gas. For this reason, for example, even if the combustion air-fuel ratio is set to the stoichiometric air-fuel ratio and the combustion of the engine 2 is stabilized, the amount of HC in the exhaust gas cannot be generally reduced. Therefore, in the present embodiment, a target peak in-cylinder pressure map is created in advance, and the target peak in-cylinder pressure Pe _max-T for each combustion stroke is acquired from the target peak in-cylinder pressure map.

The correction unit 53 is the largest of the actual in-cylinder pressure Pe _−A detected during one combustion stroke, which is detected by the in-cylinder pressure sensor 17 and stored in the actual in-cylinder pressure storage area M ₁ of the memory 55. The actual peak in-cylinder pressure Pe _max-A is obtained by selecting the pressure.
Then, the correction unit 53 determines a difference (in-cylinder pressure error) D between the actual peak in-cylinder pressure Pe _max-A and the target peak in-cylinder pressure Pe _max-T for each combustion stroke set by the target peak output setting unit 52. Each _Pe is calculated.

Further, the correction unit 53 calculates an average value D _Pe-AVE of the in _- cylinder pressure error D _Pe for each calculated combustion stroke, and when the average value D _Pe-AVE is equal to or greater than a predetermined value D _Pe0 , The basic starting injection amount Q _IJ used for starting the engine 2 from the next time is corrected so that the in-cylinder pressure error D _Pe decreases. Here, the corrected basic starting injection quantity Q _IJC has become associated with the cooling water temperature T _W acquired in step S11 to be stored in the basic starting injection amount storing area M _4.

A predetermined value D _{Pe0 that} is a condition for correcting the basic starting injection amount Q _IJ is stored in the memory 55 in advance.
The stroke number counter 54 detects the number of combustion strokes in a predetermined cylinder of the engine 2 and counts up whenever the crank angle θ _CNK detected by the crank angle sensor 16 reaches 540 degrees. Yes. Further, this count-up is performed until the time t from the start of the engine measured by a timer (not shown) built in the ECU 20 reaches a predetermined time t ₀ .

Since the air-fuel ratio control apparatus for an internal combustion engine according to an embodiment of the present invention is configured as described above, the following operations and effects are achieved.
As shown in FIG. 2, in step S11, the basic starting injection quantity setting unit 51 of the ECU20 is, reads the cooling water temperature T _W of the engine 2 detected by the water temperature sensor 12, then, in step S12, an ignition switch (not shown) Is turned on, and when it is detected that the engine speed Ne exceeds the start determination speed Ne ₀ , it is determined that the engine 2 has started (Yes route in step S12).

At this time, a timer (not shown) built in the ECU 20 starts measuring the time t from the start of the engine 2 (step S13), and then, in step S14, the stroke number counter 54 of the ECU 20 is detected by the crank angle sensor 16. The detected crank angle θ _CNK is read, and when the crank angle θ _CNK reaches 360 degrees, it is determined that the combustion stroke has started (Yes route of step S14).

The basic starting injection amount setting unit 51 reads the actual in-cylinder pressure Pe _-A detected by the in-cylinder pressure sensor 17 and stores it in the actual in-cylinder pressure storage area M ₁ in the memory 55 (steps S15 and S16).
Thereafter, until the crank angle θ _CNK detected by the crank angle sensor 16 reaches 540 degrees and it is determined that the combustion stroke is completed, the actual cylinder pressure Pe _−A is read (step S15), and the read actual cylinder is read. The storage of the internal pressure Pe _{-A in} the actual in-cylinder pressure storage area M ₁ (step S16) is repeatedly executed in a very short cycle (No route of step S18).

Thereafter, when it is determined that the crank angle θ _CNK reaches 540 degrees and the combustion stroke is completed (Yes route of step S17), the stroke number counter 54 is set to a predetermined cylinder of the engine 2 in step S18 shown in FIG. Accumulate the number of combustion strokes.
Then, in step S19, the correction unit 53, the actual peak cylinder pressure Pe _max which is the highest actual cylinder pressure in each real-cylinder pressure Pe _-A stored in the real-cylinder pressure storage area M ₁ in the memory 55 select a _-A (step S19), will now be stored in the actual peak cylinder pressure storage area M ₂ in the memory 55 a selected actual peak cylinder pressure Pe _max-a were each combustion stroke (step S20).

Steps S13~S20 described above, the engine starting time t is repeated until a predetermined time t ₀ (No route of step S21).
When the engine start time t measured by the timer reaches a predetermined time t ₀ (Yes route of step S21), the actual in-cylinder pressure storage area M1 in the memory 55 is cleared and the stroke number counter 45 is reset. At the same time, the timer is reset (steps S22 to S24), and the control ends.

Next, a method for obtaining the fuel amount (corrected basic instruction injection amount Q _IJC ) used when the engine 2 is started next time will be described. In step S31 in FIG. 4, the engine start time t is a predetermined time. When it is determined that the start of the engine 2 has been completed by reaching t ₀ (Yes route), the target peak in-cylinder pressure setting unit 52 is stored in the target peak in-cylinder pressure storage area M ₃ of the memory 55. The target peak in-cylinder pressure Pe _max-T for each combustion stroke is acquired from the target peak in-cylinder pressure map (not shown) (step S32). Incidentally, the target peak cylinder pressure Pe _max-T, based on the cooling water temperature T _W detected by the water temperature sensor 12, is selected from the target peak cylinder pressure map.

From the target peak in-cylinder pressure Pe _{max-T for} each combustion stroke obtained in step S32, the actual peak in-cylinder pressure Pe _{max-A for} each combustion stroke stored in the actual peak in-cylinder pressure storage area M ₂ (step in FIG. 3). S21) is subtracted, and the in-cylinder pressure error D _Pe is obtained. That is, the following expression (1) is calculated.
In-cylinder pressure error D _Pe = Pe _max-T -Pe _max-A (1)
In step S34, the correction unit 54 calculates an average value D _Pe-AVE of the in _- cylinder pressure error D _Pe for each combustion stroke, and whether or not the average in-cylinder pressure error D _Pe-AVE is equal to or greater than a predetermined value D _Pe0. Determine whether. In this determination, it is determined that the average in-cylinder pressure error D _Pe-AVE is equal to or greater than the predetermined value D _Pe0 (Yes route in step S34), and in step S35, all in-cylinder pressure errors D _{Pe for} each combustion stroke are negative ( If it is determined (negative) ("-" route), the basic starting injection amount Q _{IJ is} corrected by adding the basic correction amount Q _C to obtain the corrected basic starting injection amount Q _IJC (step) S36).

On the other hand, if it is determined in step S35 that the in-cylinder pressure error D _{Pe for} each combustion stroke is all positive (“+” route), the basic correction amount Q _{C with} respect to the basic start injection amount Q _IJ . Is corrected, and the corrected basic starting injection amount Q _IJC is set (step S37).
In this step S35, when the in-cylinder pressure error D _{Pe for} each combustion stroke is not all positive (positive) or not all negative (negative), the correction for the basic starting injection amount Q _IJ is not executed (“ ± mixed ”route).

Thereafter, the basic starting injection quantity Q _IJC corrected in step S36 or S37 in above, in a state associated with the cooling water temperature T _W acquired in step S11 in FIG. 2, the basic starting injection quantity storage region M of the memory 55 ₄ is stored (step S38).
Then, when starting the next time the engine 2, the cooling water temperature T _W detected by the water temperature sensor 12, the basic starting injection quantity Q _IJC corrected stored in the basic starting injection amount storing area M ₄ of the memory 55 a cooling water temperature T _W associated, if it meets or approximate, the injector 18 is controlled so as to inject fuel of the basic starting injection quantity Q _IJ after the correction.

Here, the relationship between the actual peak in-cylinder pressure Pe _max-A and the target peak in-cylinder pressure Pe _max-T for each combustion stroke stored in the actual peak in-cylinder pressure storage area M ₂ of the memory 55 and the combustion stroke is shown in FIG. Show.
The target peak in-cylinder pressures Pe _{max-T1 to} Pe _{max- T4} indicated by asterisks in FIG. 5 are target _{maximum in-} cylinder pressures set for each combustion stroke, and are obtained by step S32 in FIG. 4 described above. Value.

Further, actual peak in-cylinder pressures Pe _{max-A1 to} Pe _{max- A4} indicated by circles in FIG. 5 are the maximum in-cylinder pressures actually detected for each combustion stroke, and the above-described steps S15, S16 in FIG. This value is obtained by steps S19 and S20 in FIG.
That is, in the case shown in FIG. 5, the actual peak in-cylinder pressure Pe _{max is} always higher than the target peak in-cylinder pressure Pe _{max-T1 to} Pe _max-T4 in the first to fourth combustion strokes after the engine 2 is started. _{-A1 ~Pe max-A4} is high. Therefore, it is determined that the in-cylinder pressure errors D _{Pe1 to} D _Pe4 in the first to fourth combustion strokes are all positive. This determination is the determination of the “+” route shown in step S35 of FIG.

In the case shown in FIG. 5, if the fuel injected from the injector 18, that is, the basic starting injection amount Q _IJ is reduced, the actual peak in-cylinder pressures Pe _{max-A1 to} Pe _max-A4 are set in each combustion stroke. The target peak in-cylinder pressure Pe _{max-T1 to} Pe _{max -T4} can be approached. This is the correction of the basic starting injection amount Q _IJ in step S37 shown in FIG.
If D _Pe-AVE, which is an average value of the in-cylinder pressure errors D _{Pe1 to} D _Pe4 , is less than D _Pe0 stored in the memory 55 in advance, the basic starting injection amount Q _IJ is substantially corrected. Therefore, the basic starting injection amount Q _IJ is not corrected. This control is the control indicated by the No route in step S34 in FIG.

On the other hand, in FIG. 6, after the start of the engine 2, the fourth round of the combustion stroke, always, the target peak cylinder pressure Pe _max-T1 ~Pe _max-T4 real peak cylinder pressure than Pe _max-A1 ~Pe _{max The relationship} between the actual peak in-cylinder pressure Pe _max-A , the target peak in-cylinder pressure Pe _max-T, and the combustion stroke when _-A4 is low is shown.
In the case shown in FIG. 6, since it is determined that the in-cylinder pressure errors D _{Pe1 to} D _Pe4 in the first to fourth combustion strokes are all negative (see the “−” route in step S35 in FIG. 4). If enrichment is promoted by increasing the basic starting injection amount Q _IJ , the actual peak in-cylinder pressure Pe _{max-A1 to} Pe _max-A4 in each combustion stroke is brought close to the target peak in-cylinder pressure Pe _{max-T1 to} Pe _max-T4 . be able to. This is the correction of the basic starting injection amount Q _IJ in step S36 shown in FIG.

In this way, when the engine 2 is started next time, the actual peak in-cylinder pressure Pe _{max-A1 to} Pe _max-A4 approaches the target peak in-cylinder pressure Pe _{max-T1 to} Pe _max-T4. The performance is improved.
Thus, according to the air-fuel ratio control apparatus for an internal combustion engine according to the embodiment of the present invention, D _Pe-AVE of the difference D _Pe between the actual peak in-cylinder pressure Pe _max-A and the target peak in-cylinder pressure Pe _max-T. Is corrected to the basic start injection amount Q _IJ used for the next start of the engine 2 when the engine is greater than or equal to the predetermined value D _Pe0 , the exhaust gas performance while ensuring the startability of the engine 2 and the combustion stability immediately after the start Can be improved.

Further, after the engine 2 is started, the difference between the actual peak in-cylinder pressure Pe _max-A and the target peak in-cylinder pressure Pe _max-T of the in _- cylinder pressure calculated for each combustion stroke is all positive or negative at t ₀ during the predetermined period. And when the average D _Pe-AVE of the difference D _Pe is equal to or greater than a predetermined value D _Pe0 , the basic start injection amount Q _IJ used for the next start of the engine 2 is corrected. While avoiding an excessive correction, it is possible to improve the stability of the control and improve the exhaust gas performance. (Claim 1 )
Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and various modifications can be made without departing from the spirit of the present invention.

  In the above-described embodiment, the case where the in-cylinder pressure sensor 17 is provided in each cylinder of the engine 2 has been described as an example. However, the present invention is not limited to such a configuration. For example, the in-cylinder pressure sensor 17 may be provided in only one of the four cylinders, and the other three cylinders may be controlled assuming that the in-cylinder pressure changes in the same manner as the cylinder in which the in-cylinder pressure sensor 17 is provided. . Thereby, the number of in-cylinder pressure sensors 17 can be reduced, and it can contribute to cost reduction.

In the above-described embodiment, the stroke number counter 54 has been described as an example of a configuration in which the number of combustion strokes is counted up every time the crank angle θ _CNK detected by the crank angle sensor 16 reaches 540 degrees. It is not limited to such a configuration. For example, the number of combustion strokes may be counted up assuming that the combustion stroke has been executed each time an ignition signal _SP is transmitted to a spark plug (not shown).

It is a mimetic diagram showing the whole fuel injection control device of an internal-combustion engine concerning one embodiment of the present invention. 3 is a flowchart schematically showing a method of obtaining an actual peak in-cylinder pressure for each combustion stroke in the fuel injection control device for an internal combustion engine according to an embodiment of the present invention. 3 is a flowchart schematically showing a method of obtaining an actual peak in-cylinder pressure for each combustion stroke in the fuel injection control device for an internal combustion engine according to an embodiment of the present invention. 3 is a flowchart schematically showing correction control for a basic starting injection amount of an internal combustion engine in a fuel injection control device for an internal combustion engine according to an embodiment of the present invention. 5 is a graph schematically showing a relationship between an actual peak in-cylinder pressure and a target peak in-cylinder pressure for each combustion stroke of the internal combustion engine in the fuel injection control device for the internal combustion engine according to the embodiment of the present invention. 5 is a graph schematically showing a relationship between an actual peak in-cylinder pressure and a target peak in-cylinder pressure for each combustion stroke of the internal combustion engine in the fuel injection control device for the internal combustion engine according to the embodiment of the present invention.

Explanation of symbols

2 Engine (Internal combustion engine)
12 Water temperature sensor (temperature detection means)
14 Injector (fuel injection device)
17 In-cylinder pressure detection unit (in-cylinder pressure detection means)
51 Start-up injection amount setting section (basic start-up injection amount setting means)
52 Target peak in-cylinder pressure setting unit (target peak in-cylinder pressure setting means)
53 Correction unit (correction means)
D _Pe cylinder pressure error (difference)
D _Pe-AVE average in-cylinder pressure error (average of difference)
D _Pe0 predetermined value Pe _max-T target peak in-cylinder pressure Q _IJ basic starting injection amount t ₀ predetermined period T _W Cooling water temperature

Claims (1)

A fuel injection device for supplying fuel to the internal combustion engine;
Temperature detecting means for detecting the temperature of the internal combustion engine;
Basic start in which a basic start injection amount, which is the amount of fuel injected every cycle during the elapse of a predetermined period from the start of the internal combustion engine, is set according to the internal combustion engine temperature detected by the temperature detection means Injection amount setting means;
Target peak in-cylinder pressure setting means for setting a target peak in-cylinder pressure of in-cylinder pressure for each combustion stroke during the predetermined period in accordance with the internal combustion engine temperature;
In-cylinder pressure detecting means for detecting the in-cylinder pressure of the internal combustion engine;
The difference between the actual peak in-cylinder pressure, which is the maximum of the in-cylinder pressure during the combustion stroke detected by the in-cylinder pressure detecting means, and the target peak in-cylinder pressure set by the target peak output setting means is calculated as the combustion stroke. And a correction means that corrects the basic starting injection amount so that the difference decreases when the average of the difference for each combustion stroke calculated is greater than or equal to a predetermined value.
The injection amount correction means includes
When the difference for each combustion stroke is all positive, that is, during the predetermined period, the actual peak in-cylinder pressure is always higher than the target peak in-cylinder pressure, and the average of the differences for each combustion stroke is greater than or equal to a predetermined value. Correction is made so that the difference decreases by subtracting the basic starting injection amount,
When the difference for each combustion stroke is all negative, that is, during the predetermined period, the actual peak in-cylinder pressure is always lower than the target peak in-cylinder pressure, and the average of the differences for each combustion stroke is a predetermined value or more, Correction is made so that the difference decreases by adding the basic starting injection amount,
The fuel injection control device for an internal combustion engine , wherein the basic starting injection amount is not corrected when the differences for each combustion stroke are not all positive or all negative .

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