JPH116459A - Fuel injection control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out traveling even in the case where an intake rate detecting means is in an abnormal condition by providing a minimum injection rate in a stable fuel injection state even if an intake air rate is changed through calculating a maximum injection rate using a signal such as an intake air rate, and using an allowable maximum injection rate adjacent to maximum supercharge. SOLUTION: An operating condition detecting means 1 is provided to detect an operating condition, and a fuel injection rate is calculated from an output of the operating condition detecting means 1 by a fuel injection rate calculating means 2. From each output of the operating condition detecting means 1, an intake air rate calculating means 3, and each parameter detecting means 4, a maximum fuel injection rate at the time of a normal operation is calculated by a normal time maximum fuel injection rate calculating means 5, and an allowable maximum injection rate is set by an allowable maximum injection rate calculating means 6. A final maximum fuel injection rate is calculated from each output of both calculating means 5, 6 by a final maximum injection rate calculating means 7. A final injection rate is set from each output of the calculating means 2, 7 by a fuel injection rate setting means 8, and an injection rate is controlled from its output by a fuel injection rate controlling means 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control device for an internal combustion engine, and more particularly to a technology for controlling a maximum fuel injection amount of a diesel engine.

[0002]

2. Description of the Related Art As a conventional maximum fuel injection amount control method, there is a technique described in Japanese Patent Application Laid-Open No. 7-158483. This means that the maximum injection amount is calculated from the intake air amount and the engine speed, the basic injection amount is calculated from the accelerator opening and the engine speed, and the smaller one is used as the final injection amount and the maximum injection amount is used as the basic value. When the injection amount exceeds, the final injection amount is further corrected by using the intake air amount, the basic injection amount, and the maximum injection amount.

[0003]

However, in the above-described method for setting the maximum fuel injection amount, when the supercharging pressure is increased and the waist gate valve provided to protect the supercharger is operated, Or, if the turbocharger's nozzle opening changes such that the turbo nozzle's opening changes with respect to the intake pressure, the amount of intake air changes suddenly, adversely affecting operability. I understand. In addition, it has been found that when the output of the intake air amount detecting means drops significantly due to deterioration or the like below the normal value, there is a possibility that the startability may be deteriorated without supplying the fuel or the engine may be stopped.

[0004]

Means for Solving the Problems The present invention has been made in view of such a conventional problem, and usually uses a maximum injection amount calculated from an intake air amount or the like, and uses the maximum injection amount as a value. By providing an upper limit value and changing the upper limit value at atmospheric pressure, it is possible to stably supply fuel up to the maximum load and prevent deterioration in drivability. On the other hand, even if the intake air amount detection means has deteriorated and the output has become smaller than normal, or if it has an abnormal value due to the effect of noise, at least normal driving or driving to a repair shop is possible. And

[0005]

Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a fuel injection control device for an internal combustion engine according to a first embodiment of the present invention. First, the configuration will be described. An operating state detecting means (1) for detecting a basic operating state such as an engine speed, an accelerator opening and a water temperature, and a basic fuel injection amount based on an output of the operating state detecting means (1). (2), intake air amount measuring means (3), each parameter detecting means (4), the operating state detecting means (1), and intake air amount measuring means (3). Normal maximum fuel injection amount calculating means (5) for calculating the maximum fuel injection amount during normal operation from the output of each parameter detecting means (4), the operating state detecting means (1) and each parameter detecting means (4) ), The maximum allowable injection amount calculating means for setting the maximum allowable injection amount from the output, and the normal maximum fuel injection amount calculating means (5) and the maximum allowable injection amount calculating means (6). Calculating the maximum fuel injection amount A large injection amount calculating means (7), a fuel injection amount setting means (8) for setting a final injection amount from outputs of the fuel injection amount calculating means (2) and the final maximum injection amount calculating means (7); And a fuel injection amount control means (9) for controlling the injection amount from the output of the fuel injection amount setting means (8). Here, each parameter detection means (4) may be the same as or a part of the operation state detection means (1).

FIG. 2 is a block diagram showing a configuration of a fuel injection control device for an internal combustion engine according to a second embodiment of the present invention. First, the configuration will be described. An operating state detecting means (1) for detecting a basic operating state such as an engine speed, an accelerator opening and a water temperature, and a basic fuel injection amount based on an output of the operating state detecting means (1). (2), intake air amount measuring means (3), each parameter detecting means (4), the operating state detecting means (1), and intake air amount measuring means (3). Normal maximum fuel injection amount calculating means (5) for calculating the maximum fuel injection amount during normal operation from the output of each parameter detecting means (4), the operating state detecting means (1) and each parameter detecting means (4) ), The output of the minimum and maximum injection amount calculating means (6a) for setting the minimum and maximum fuel injection amount, and the outputs of the normal and maximum fuel injection amount calculating means (5) and the minimum and maximum injection amount calculating means (6a). To the final maximum fuel injection amount And a fuel injection quantity setting means (8) for setting a final injection quantity from the outputs of the fuel injection quantity calculation means (2) and the final maximum injection quantity calculation means (7). ) And a fuel injection amount control means (9) for controlling the injection amount from the output of the fuel injection amount setting means (8). Here, each parameter detection means (4) may be the same as or a part of the operation state detection means (1).

Next, the operation will be described. 3 to 16 show a flow of the embodiment and tables and maps necessary for the flow. The calculation of the maximum fuel injection amount will be described later with reference to FIGS.

First, the flow of FIG. 3 will be described for the calculation of the intake air amount. First, in step S1, the output voltage Us of a means for detecting the amount of intake air, such as an air flow meter, is read. In S2, the flow rate is converted using a voltage-flow rate conversion table as shown in FIG. In S3, a weighted average process of the values obtained in S2 is performed, and the process ends as QasO. This processing is performed at predetermined time intervals such as 4 msec JOB.

FIG. 5 shows a calculation flow of the intake air amount entering the cylinder, which is calculated at a timing synchronized with the rotation of the engine or correspondingly. First, at S11, the engine speed Ne
Is read and converted into an intake air amount per intake by an equation as shown in FIG. In S13, a delay process corresponding to the transport delay from the intake air amount measuring means to the collector is performed, and in S14, a delay process corresponding to the dynamics in the collector is performed by an equation as shown in FIG.
The process ends as c.

FIG. 6 is a flowchart for calculating the basic fuel injection amount, and the processing is performed at a timing synchronized with the rotation. First, the engine speed Ne is read in S21. In step S22, the accelerator opening Cl is read. In S23, the fuel injection amount is set from Ne and Cl from the basic fuel injection amount map as shown in FIG. 7 and is set to Mqdrv. In S24, correction such as an increase in the water temperature is performed, and the process ends as the basic fuel injection amount Qsol1.

FIG. 8 shows a flow for calculating the maximum fuel injection amount in the fuel injection control device for an internal combustion engine according to the first embodiment. This process is performed at a timing synchronized with the engine rotation. First, at S32, the engine speed Ne is read, and at S32, a limit excess air ratio Klamb is calculated from the limit excess air ratio table as shown in FIG. S3
In step 3, the cylinder intake air amount Qac is read, and in step S34, the normal maximum injection amount Qfuls is calculated using an equation as shown in FIG. At S35, the atmospheric pressure Pa is read from the atmospheric pressure detecting means, and at S36, a correction coefficient KPa1 is calculated from a table as shown in FIG. 10, for example. This characteristic is determined, for example, from an allowance for air density improvement due to a rise in atmospheric pressure. In S37, the allowable maximum injection amount basic value Q is obtained from the basic value table of the allowable maximum injection amount as shown in FIG.
compute flub. This characteristic is determined from the characteristics of the supercharger, the operating point of the wastegate, and the like. KPa1 in S38
Then, the allowable maximum injection amount Qfluu is calculated from the formulas and Qfulub using an expression as shown in the figure. In S39, the normal maximum injection amount Q
fuss is compared with the allowable maximum injection amount Qful. If the former is large, the process proceeds to S40, and if the latter is large, the process proceeds to S41. In S40, the process ends with Qful being the final maximum injection amount Qful. In S41, the process is terminated with Qfuls as the final maximum injection amount.

FIG. 12 shows a flow for calculating the maximum fuel injection amount in the fuel injection control device for an internal combustion engine according to the second embodiment. This process is performed at a timing synchronized with the engine rotation. First, at step S51, the engine speed Ne is read, and at step S52, a limit excess air ratio Klamb is calculated from a limit excess air ratio table as shown in FIG. S
At step 53, the cylinder intake air amount Qac is read, and at step S54, the normal maximum injection amount Qfuls is calculated by an equation as shown in the figure. At S55, the atmospheric pressure Pa is read from the atmospheric pressure detecting means, and at S56, a correction coefficient KPa2 is calculated from a table as shown in FIG. 13, for example. This characteristic is determined, for example, from an allowance for air density improvement due to a rise in atmospheric pressure. In S57, the minimum maximum injection amount basic value Qfullb is calculated from the engine speed from the basic value table of the allowable maximum injection amount as shown in FIG. 14, for example. This characteristic is determined by such a characteristic that the vehicle can run even if the intake air amount detecting means becomes abnormal. In S58, a minimum and maximum injection amount Qfull is calculated from KPa2 and Qfullb by an equation as shown. In S59, the normal maximum injection amount Qfuls and the minimum maximum injection amount Qfu
ll are compared, and if the former is large, go to S60; if the latter is large, S60
Proceed to 61. In S60, Qfuls is set as the final maximum injection amount Qful, and the process ends. In S61, Qful
The processing is ended with 1 as the final maximum injection amount.

FIG. 15 is a flowchart for finally setting the fuel injection amount, which is calculated in synchronization with the engine rotation. First, S
At 71, the basic fuel injection amount Qsol1 and the maximum fuel injection amount Qf
ul and, if the former is large, the process proceeds to S72, and Qful is used as the fuel injection amount Qsol. If the former is small, the process proceeds to S73, where Qsol1 is set to Qsol, and the process ends. FIG. 16 is a setting example of a map for converting the fuel injection amount into a signal to be sent to the control device.

[0014]

As described above, the normal injection amount is calculated using the signal of the intake air amount and the like at the normal time, and the allowable maximum injection amount is used near the maximum supercharging, so that the waste gate and the turbine nozzle can be used. The fuel can be stably injected even if the opening degree of the intake air changes and the intake air amount changes, and the stable injection can stabilize the intake air amount, so that the vehicle can run stably even near the maximum supercharging. On the other hand, by providing the minimum maximum injection amount, the vehicle can travel even if the intake air amount detecting means becomes abnormal, and can move to a repair shop.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a fuel injection control device for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a fuel injection control device for an internal combustion engine according to a second embodiment of the present invention.

FIG. 3 is an intake air amount calculation flow.

FIG. 4 is a voltage-flow rate conversion table.

FIG. 5 is a calculation flow of an intake air amount entering a cylinder.

FIG. 6 is a flowchart for calculating a basic fuel injection amount.

FIG. 7 is a basic fuel injection amount map.

FIG. 8 is a flowchart for calculating a maximum fuel injection amount in the fuel injection control device for the internal combustion engine according to the first embodiment of the present invention.

FIG. 9 is a limit excess air ratio table.

FIG. 10 is an atmospheric pressure correction table.

FIG. 11 is a basic value table of an allowable maximum injection amount.

FIG. 12 is a flowchart for calculating a maximum fuel injection amount in the fuel injection control device for an internal combustion engine according to the second embodiment of the present invention.

FIG. 13 is an atmospheric pressure correction table.

FIG. 14 is a basic value table of an allowable maximum injection amount.

FIG. 15 is a flowchart for finally setting a fuel injection amount.

FIG. 16 is a setting example of a map for converting a fuel injection amount into a signal to be sent to a control device.

Claims (6)

[Claims] An operating state detecting means for detecting an engine operating state such as an engine speed, an accelerator opening, and a water temperature;
A fuel injection amount calculating means (2) for calculating a basic fuel injection amount from an output of the operating state detecting means (1), an intake air amount measuring means (3), and each parameter detecting means (4);
Normal maximum fuel injection amount calculating means (5) for calculating the normal maximum fuel injection amount from the outputs of the operating state detecting means (1), the intake air amount measuring means (3) and the parameter detecting means (4). An allowable maximum injection amount calculating means (6) for calculating an allowable maximum injection amount from outputs of the operating state detecting means (1) and the respective parameter detecting means (4); and the normal maximum fuel injection amount calculating means ( 5) and a final maximum injection amount calculating means (7) for calculating a final maximum fuel injection amount from outputs of the allowable maximum injection amount calculating means (6), and an output of the final maximum injection amount calculating means (7). A fuel injection amount setting means (8) for comparing the output of the fuel injection amount calculating means (2) with the smaller one as a final fuel injection amount; A fuel injection amount control means (9) for controlling the injection amount; Fuel injection control device for an internal combustion engine. 2. The fuel injection control device for an internal combustion engine according to claim 1, wherein said allowable maximum injection amount calculating means (6) calculates the allowable maximum injection amount from the engine rotation. For controlling internal combustion engine fuel injection. 3. The fuel injection control device for an internal combustion engine according to claim 1, wherein the allowable maximum injection amount calculating means calculates the allowable maximum injection amount at atmospheric pressure when calculating the allowable maximum injection amount. A fuel injection control device for an internal combustion engine, characterized in that it is changed. 4. An operating state detecting means (1) for detecting an engine operating state such as an engine speed, an accelerator opening and a water temperature;
A fuel injection amount calculating means (2) for calculating a basic fuel injection amount from an output of the operating state detecting means (1), an intake air amount measuring means (3), and each parameter detecting means (4);
Normal maximum fuel injection amount calculating means (5) for calculating the normal maximum fuel injection amount from the outputs of the operating state detecting means (1), the intake air amount measuring means (3) and the parameter detecting means (4). A minimum / maximum injection amount calculating unit (6a) for calculating a minimum / maximum injection amount from outputs of the operating state detecting unit (1) and each parameter detecting unit (4); (5) a final maximum injection amount calculating means (7) for calculating a final maximum injection amount from outputs of the minimum and maximum injection amount calculating means (6a), and an output of the final maximum injection amount calculating means (7). The fuel injection amount calculating means (2)
A fuel injection amount setting means (8) for comparing the output with the fuel injection amount and setting a smaller one as a final fuel injection amount; (9) A fuel injection control device for an internal combustion engine, comprising: 5. The fuel injection control device for an internal combustion engine according to claim 4, wherein the minimum and maximum injection amount calculating means (6a) calculates the minimum and maximum injection amount from the engine rotation. A fuel injection control device for an internal combustion engine. 6. The fuel injection control device for an internal combustion engine according to claim 4, wherein the minimum and maximum injection amount calculating means (6a) changes the minimum and maximum injection amount at atmospheric pressure when calculating the minimum and maximum injection amount. A fuel injection control device for an internal combustion engine.