JP5634200B2 - Internal combustion engine start injection amount control method and fuel injection control device - Google Patents

Description

  The present invention relates to a starting injection amount control method and a fuel injection control device for an internal combustion engine, and more particularly, to an improvement in starting performance of a diesel engine.

In fuel injection control of internal combustion engines, it is well known that various measures have been proposed and put into practical use from various viewpoints.
For example, in order to improve startability, the quality of startability is determined from the start time of the diesel engine, and the fuel injection amount at the time of restart is increased according to the degree of startability deterioration. It has been proposed (see, for example, Patent Document 1).

JP 2000-161118 A (page 3-8, FIGS. 1-8)

However, in general, the engine start time is defined as the time from the fall of the battery voltage due to the start of rotation of the starter motor to a certain engine speed, and the time when the battery voltage falls is the start of the engine start time. Therefore, every time the start time is measured, the start time varies due to the difference in the piston position when the engine is stopped, and there is a problem that it is not always reliable as a parameter for determining whether the startability is good or bad.
On the other hand, in the fuel injection amount control, the fuel injection amount is obtained by acquiring fuel injection amount data at the time of standard engine operation, storing it as reference data, and using the parameters as described above as an index. Although it is common to set the required fuel injection amount, there may be unexpected variations in the operating characteristics of individual engines, or when the operating characteristics of the entire vehicle exceed the expected range. In such a case, there is a problem that an appropriate fuel injection amount cannot be obtained, and in particular, the startability of the engine is deteriorated.

  The present invention has been made in view of the above circumstances, and enables accurate control of the fuel injection amount at the start without being affected by the operating characteristics of the individual engines or the driving state of the vehicle, thereby improving the startability of the engine. An internal combustion engine start injection amount control method and a fuel injection control device that can be further improved are provided.

In order to achieve the above object of the present invention, an internal combustion engine start injection amount control method according to the present invention comprises:
A starting injection amount, which is a target fuel injection amount at the time of starting the internal combustion engine, is obtained based on at least the rotational speed of the internal combustion engine and the cooling water temperature of the internal combustion engine, and the fuel injection to the internal combustion engine is the starting injection amount. A starting injection amount control method for correcting and controlling the starting injection amount in a fuel injection control device configured to be capable of starting injection control by feedback control,
Using the detected rotation speed of the internal combustion engine and the cooling water temperature of the internal combustion engine as input parameters, a start injection amount obtained from a predetermined start injection amount map is determined according to an increase time of the rotation speed of the internal combustion engine. Is corrected using the correction coefficient to be performed, the starting injection control is performed by the corrected starting injection amount,
The predetermined start injection amount map is set so as to be able to take out a start injection amount in a predetermined standard internal combustion engine using the rotational speed of the internal combustion engine and the cooling water temperature of the internal combustion engine as input parameters,
The correction coefficient is a rotation that is an increase time of an actual rotation speed in a predetermined rotation speed range of the internal combustion engine with respect to a reference rotation increase time that is a rotation speed increase speed in the predetermined rotation speed range of the standard internal combustion engine As a percentage of the rise time ,
The reference rotation rise time is obtained from a preset reference rotation rise time map,
The reference rotation increase time map is set so that a reference rotation increase time is obtained by using a stop time until the start of the internal combustion engine and a cooling water temperature of the internal combustion engine as input parameters, and the reference rotation increase time is determined in advance. The time required to increase the predetermined rotational speed in various combinations of the stop time and the cooling water temperature of the standard internal combustion engine provided,
The rotation rise time is obtained from a rotation rise time learning map,
The rotation increase time learning map is set so that the rotation increase time can be obtained by using the stop time until the start of the internal combustion engine and the cooling water temperature of the internal combustion engine as input parameters. It is actually obtained as the time required for the increase in the rotational speed, and is configured to be updated as a learning value under a predetermined condition .
In order to achieve the above object of the present invention, a fuel injection control device according to the present invention includes:
A starting injection amount, which is a target fuel injection amount at the time of starting the internal combustion engine, is obtained based on at least the rotational speed of the internal combustion engine and the cooling water temperature of the internal combustion engine, and the fuel injection to the internal combustion engine is performed with the start injection amount. A fuel injection control device provided with an electronic control unit configured to be capable of executing start injection control by feedback control,
The electronic control unit is
Using the detected rotation speed of the internal combustion engine and the cooling water temperature of the internal combustion engine as input parameters, a start injection amount obtained from a predetermined start injection amount map is determined according to an increase time of the rotation speed of the internal combustion engine. Is corrected using the correction coefficient to be performed, the starting injection control is performed by the corrected starting injection amount,
The predetermined start injection amount map is set so as to be able to take out a start injection amount in a predetermined standard internal combustion engine using the rotational speed of the internal combustion engine and the cooling water temperature of the internal combustion engine as input parameters,
The correction coefficient is a rotation that is an increase time of an actual rotation speed in a predetermined rotation speed range of the internal combustion engine with respect to a reference rotation increase time that is a rotation speed increase speed in the predetermined rotation speed range of the standard internal combustion engine As a percentage of the rise time ,
Further, the electronic control unit includes:
The reference rotation rise time is determined from a preset reference rotation increase time map, and the rotation increase time is determined from a rotation increase time learning map.
The reference rotation increase time map is set so that a reference rotation increase time is obtained by using a stop time until the start of the internal combustion engine and a cooling water temperature of the internal combustion engine as input parameters, and the reference rotation increase time is determined in advance. The time required to increase the predetermined rotational speed in various combinations of the stop time and the cooling water temperature of the standard internal combustion engine provided,
The rotation increase time learning map is set so that the rotation increase time can be obtained by using the stop time until the start of the internal combustion engine and the cooling water temperature of the internal combustion engine as input parameters. actually is obtained as the time required for the rotational speed is increased, under a predetermined condition, in which updated as a learning value formed by so that configuration.

  According to the present invention, since the starting injection amount is corrected based on the actual rotational state of the engine at the time of starting, it is influenced by variations in operating characteristics of individual engines and differences in operating characteristics of vehicles. Thus, an accurate start injection amount is always ensured, and the engine startability can be further improved as compared with the prior art, and as a result, fuel efficiency can be improved.

It is a block diagram which shows the structural example of the fuel-injection control apparatus in embodiment of this invention. 2 is a flowchart showing a procedure of a starting injection amount control process for an internal combustion engine in an embodiment of the present invention, which is executed by an electronic control unit constituting the fuel injection control device shown in FIG. 1. FIG. 2 is a functional block diagram showing functional blocks of the electronic control unit when a start injection amount control process of the internal combustion engine is executed by the electronic control unit constituting the fuel injection control device shown in FIG. 1. It is a characteristic diagram showing an example of a change characteristic of the engine speed with respect to a time change for explaining a rotation rise time acquired at the time of learning a rotation rise time learning map. FIG. 6 is a characteristic diagram showing an example of a change characteristic of an engine speed with respect to a time change for explaining a rotation increase time acquired when a reference rotation increase time map is adapted. FIG. 4 is an explanatory diagram showing specific numerical examples of a rotation increase time learning map, a reference rotation increase time map, a start injection amount lower limit map, a start injection amount upper limit map, and a start injection amount map in FIG. 3. It is explanatory drawing which showed the specific numerical example of the correction | amendment start injection quantity obtained by the start injection quantity control process of the internal combustion engine in embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 7.
The members and arrangements described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention.
Initially, the structural example of the fuel-injection control apparatus in embodiment of this invention is demonstrated, referring FIG.
This fuel injection control device is realized, for example, in a four-wheel vehicle using a diesel engine (hereinafter referred to as “engine”) 1 as an internal combustion engine, and an electronic control unit (“ECU” in FIG. 1). 2) and the fuel injection device 3 are configured as main components.

The electronic control unit 2 controls the fuel injection operation to the engine 1 by the fuel injection device 3 and performs various control processes necessary for the operation of the vehicle.
The electronic control unit 2 includes, for example, a microcomputer (not shown) having a known and well-known configuration, a storage element (not shown) such as a RAM and a ROM, and an input interface circuit ( And an output interface circuit (not shown) as main components.

  The electronic control unit 2 includes an output signal of an accelerator opening sensor 11 that detects an accelerator opening required for execution of a starting injection amount control process described later, a rotation sensor 12 that detects an engine speed, An output signal of a vehicle speed sensor 13 for detecting the vehicle speed of the vehicle, an output signal of a water temperature sensor 14 for detecting a water temperature of engine cooling water (hereinafter referred to as “engine cooling water temperature”), and an output signal of an outside air temperature sensor 15 for detecting the outside air temperature. The output signal of the atmospheric pressure sensor 16 for detecting the atmospheric pressure is inputted.

The fuel injection device 3 is typified by, for example, a common rail fuel injection device. The fuel injection device 3 is configured to inject and supply fuel into the cylinders of the engine 1 via the fuel injection valve 4 at a target injection amount determined by control from the electronic control unit 2.
In general, a plurality of fuel injection valves 4 are provided in accordance with the number of cylinders, but in FIG.

FIG. 2 shows a subroutine flowchart showing a procedure for starting injection amount control of the internal combustion engine in the embodiment of the present invention, and FIG. 3 shows an electronic control unit 2 in the embodiment of the present invention. Functional block diagrams showing the functions of the electronic control unit 2 for executing the starting injection amount control of the internal combustion engine are respectively shown. Hereinafter, the internal combustion engine according to the embodiment of the present invention will be described with reference to these drawings. The engine starting injection amount control will be described. FIG. 6 shows an example of specific numerical values of various maps shown in the functional block diagram of FIG. 2, and this will also be referred to as appropriate in the following description.
First, the start injection amount control of the internal combustion engine in the embodiment of the present invention will be described generally. This start injection amount control is determined in advance using the engine speed and the engine coolant temperature as input parameters. A fuel injection amount at the time of starting (hereinafter referred to as “starting injection amount”) based on a standard engine obtained from the starting injection amount map is a correction coefficient (hereinafter referred to as “rotational increase”) corresponding to the actual operating characteristics of the engine 1. The fuel injection control is performed using the correction result as a starting injection amount at the time of starting the engine. Here, the start injection amount map is mapped so that a suitable start injection amount for various combinations of engine speed and engine coolant temperature in a standard engine can be obtained using the engine speed and engine coolant temperature as input parameters. (Details will be described later).

Hereinafter, the starting injection amount control of the internal combustion engine in the embodiment of the present invention will be specifically described.
When the process is started by the electronic control unit 2, it is first determined whether or not the fuel injection control is in the start mode (see step S102 in FIG. 2).
The fuel injection control itself is one of the controls conventionally performed by using the electronic control unit 2, and the control state is a start mode that is performed in consideration of ensuring the start of the engine 1 and ensuring the stability. And the normal operation mode after starting normally, and the start injection amount control processing in the embodiment of the present invention is particularly suitable for being executed in the start mode. Therefore, it is determined whether or not the fuel injection control is in the start mode.
Note that the start mode is fuel injection control that is generally performed after cranking is started until the engine speed of the engine 1 reaches the idle speed.

  Therefore, in step S102, when it is determined that the injection control is in the start mode (in the case of YES), the process proceeds to step S104 described below, while in the case where it is determined that the injection mode is not in the start mode (NO). In this case, assuming that the start mode has already been executed, the fuel injection control by the electronic control unit 2 shifts to the normal operation mode (see step S122 in FIG. 2).

In step S104, the starting injection amount is calculated.
The calculation of the starting injection amount immediately after the engine 1 is started does not take into account the rotation increase time correction coefficient described later, and is based on the same processing as in the prior art. That is, in step S104, the start injection amount is calculated using the start injection amount map 25 (see FIGS. 3 and 6) stored in advance in the electronic control unit 2, and the actual engine speed at this time point. And the engine cooling water temperature (engine water temperature), the starting injection amount corresponding to the combination of these two parameters is read out.

Here, the start injection amount map (indicated as “MAP5 start injection amount MAP” in FIGS. 3 and 6) 25 is a fuel injection amount at start-up for various combinations of engine speed and engine coolant temperature, that is, start-up. The injection amount is mapped so as to be readable with the engine speed and the engine coolant temperature as inputs. The starting injection amount map 25 in the embodiment of the present invention is updated based on the actual operation of the engine 1 through a learning process as will be described later.
The initial injection values are mapped as initial values for various combinations of engine speed and engine cooling water temperature acquired in the same type of vehicle equipped with an engine with standard characteristics, usually called a central product. Is stored in the electronic control unit 2 as the start injection amount map 25, and after the vehicle is first driven by the user, the correction obtained in accordance with the actual start situation of the engine 1 by the learning process as described later The starting injection amount is updated.

  In the specific example of the starting injection amount map 25 shown in FIG. 6, the numerical values “0”, “200”, “400”, “800”,. r / min), and the numbers “−25”, “−15”, “0”, “10”, “20”, “30”... in the leftmost column indicate the engine coolant temperature. Represents. A starting injection amount (mg / st) with respect to the corresponding engine speed and engine coolant temperature is set at the position of each grid point on the map.

After the start injection amount is calculated as described above, the start injection amount is injected and the start cranking is started (see step S106 in FIG. 2).
Next, a condition for determining whether or not the learning value of the rotation increase time learning map (described as “MAP1 rotation increase time learning MAP” in FIGS. 3 and 6) 21 can be updated by the electronic control unit 2 is described below. It is determined whether or not a certain learning permission condition is satisfied (see step S108 in FIG. 2).

  In the embodiment of the present invention, when all of the following three conditions are satisfied, the learning permission condition is satisfied (in the case of YES), the process proceeds to step S110, which will be described later. If any of the conditions is not satisfied, it is determined that the learning permission condition is not satisfied (in the case of NO), and the fuel injection control by the electronic control unit 2 is performed assuming that the start injection amount correction is not performed by the processing after step S110. Will shift to start mode end processing (see step S120 in FIG. 2).

In the learning permission condition in the embodiment of the present invention, three elements of a battery voltage, an outside air temperature, and an atmospheric pressure are set.
That is, in the embodiment of the present invention, the three conditions are that the battery voltage exceeds a predetermined voltage, the outside air temperature is below a predetermined temperature, and the atmospheric pressure exceeds a predetermined pressure. It is assumed that the learning permission condition is satisfied when it is satisfied.
Here, the above-mentioned predetermined voltage value, predetermined temperature, and predetermined atmospheric pressure should be set to appropriate values based on tests, simulation results, and the like according to specific conditions of each vehicle. Is. In the embodiment of the present invention, the predetermined voltage is set to 12000 mv, the predetermined temperature is set to 35 degC, and the predetermined atmospheric pressure is set to 860 hPa (see FIG. 3).
The reason why the above three elements are used in the learning permission condition is that it is considered to be a factor that has a particularly great influence on the starting characteristics of the engine 1.

Next, in step S110, engine speed increase time calculation is performed.
That is, the engine speed increase time calculation (engine rotation increase time calculation) at the time of start, which is written as a learning value in the rotation increase time learning map 21 described below, is performed.
Here, first, the rotation increase time learning map 21 is detected by the water temperature sensor 14 and the stop time of the engine 1 (hereinafter referred to as “engine stop time”) from when the engine 1 was most recently stopped until the current start. The engine rotation speed rise time for various combinations of the engine cooling water temperatures is configured to be readable (see FIGS. 3 and 6).

  Here, the engine stop time is measured by the electronic control unit 2 so as to measure the stop time of the engine 1 from when the engine 1 was most recently stopped until the current start by execution of so-called timing software that measures time. The time measurement result is used. In order to count the engine stop time, the electronic control unit 2 can be timed by receiving power supply even after an ignition switch (not shown) is turned off. The time measurement result is stored in an appropriate storage area of the electronic control unit 2, and as described later, the rotation increase time is read by the rotation increase time learning map 21 and the reference rotation increase time is read by the reference rotation increase time map 22. It has come to be offered.

Furthermore, the rotation increase time t1 is defined as the time until the engine speed at the start exceeds the preset measurement start speed Na and reaches the preset measurement end speed Nb ( (See FIG. 4). In FIG. 4, the horizontal axis indicates the elapsed time from the engine start, and the vertical axis indicates the engine speed.
In the embodiment of the present invention, the time until the engine rotation speed detected by the rotation sensor 12 exceeds the measurement start rotation speed Na and reaches the measurement end rotation speed Nb by execution of so-called timing software by the electronic control unit 2. Is measured, and the measurement result is set as the rotation rise time t1.
Then, the rotation increase time t1 calculated as described above is written in the rotation increase time learning map 21 as a learning value (see step S112 in FIG. 2 and FIG. 3).
Note that the measurement start rotation speed Na and the measurement end rotation speed Nb should be set arbitrarily, but in the embodiment of the present invention, the engine 1 is generally started and changes relatively slowly for a while. After increasing at a rate, the rotation speed is set in a range in which the rotation speed rapidly increases toward the rotation speed near the idle rotation speed (see FIG. 4).
That is, the measurement start rotational speed Na is a rotational speed in the vicinity where the rapid increase in the rotational speed after the engine 1 is started and increased at a relatively slow change rate for a while, and the measurement end rotational speed Nb is This is the rotational speed in the vicinity of the transition from the sudden increase in rotational speed to the idle rotational speed region.

  In the specific example of the rotation rise time learning map 21 shown in FIG. 6, the numerical values of “0”, “30”, “60”,... In the uppermost row respectively indicate the engine stop time (sec). Each value of “−25”, “−15”, “0”, “10”, “20”, “30”... In the leftmost column represents the engine coolant temperature. A corresponding engine stop time and rotation increase time t1 (sec) with respect to the engine cooling water temperature are set at the positions of the respective grid points on the map.

Next, a rotation increase time correction coefficient is calculated (see step S114 in FIG. 2).
The rotation increase time correction coefficient is a coefficient used for the correction process of the starting injection amount previously calculated in step S104 (details will be described later). For the calculation, the rotation increase time learning map 21 and the reference rotation increase time are used. A map 22 is used (see FIGS. 3 and 6).
First, a reference rotation increase time map (indicated as “MAP2 reference rotation increase time MAP” in FIGS. 3 and 6) 22 is used in an engine that is a reference (or standard) with engine stop time and engine cooling water temperature as input parameters. The map is configured to be able to obtain the rotation rise time (hereinafter referred to as “reference rotation rise time”), and the basic configuration thereof is the same as the previous rotation rise time learning map 21.

The reference rotation increase time map 22 is stored in advance in an appropriate storage area of the electronic control unit 2 (see FIG. 3).
The reference rotation increase time t2 is measured as the time until the engine speed at the start exceeds the measurement start speed Na and reaches the measurement end speed Nb in the standard vehicle.
FIG. 5 shows an example of a change in the elapsed time from the start of the engine and the engine speed in the standard vehicle, and the rotation rise time t2 exceeds the measurement start speed Na as described above. It is shown that it is measured as the time until the rotation speed Nb reaches the end of measurement. In FIG. 5, the horizontal axis indicates the elapsed time from the engine start, and the vertical axis indicates the engine speed.
Note that the measurement start rotation speed Na and the measurement end rotation speed Nb are the same as those used when obtaining the previous rotation rise time t1.

  In the specific example of the reference rotation rise time map 22 shown in FIG. 6, the numerical values “0”, “30”, “60”, “90”,. (Sec), and the numbers “−25”, “−15”, “0”, “10”, “20”, “30”... In the leftmost column represent the engine coolant temperature. ing. A corresponding engine stop time and a reference rotation rise time t2 (sec) with respect to the engine coolant temperature are set at the positions of the grid points on the map.

  The rotation increase time correction coefficient is calculated from the rotation increase time t1 read from the previous rotation increase time learning map 21 and the rotation increase time t2 read from the reference rotation increase time map 22 at the time of calculation. Assuming that the rotation rise time correction coefficient is α, α = t1 / t2 is obtained. In FIG. 3, the calculation of the rotation rise time correction coefficient is represented by a division symbol (÷).

After the rotation increase time correction coefficient is calculated as described above, the corrected start injection amount is calculated (see step S116 in FIG. 2).
In other words, the corrected starting injection amount is obtained as a result of multiplying the starting injection amount obtained in step S104 earlier by the rotation increase time correction coefficient (see FIG. 3).
Next, the start injection amount map 25 is updated, and the start mode is terminated (see steps S118 and S120 in FIG. 2).
That is, in the embodiment of the present invention, the corrected starting injection amount obtained in the process of the previous step 116 is subjected to a limiter process as described below and is limited to a predetermined range. Yes. Then, after the limiter process is performed, the start injection amount map 25 is written to read the start injection amount by the next start injection amount map 25, and the start injection amount map 25 is updated. Yes.

In the limiter process in the embodiment of the present invention, the upper limit of the corrected start injection amount is limited to a predetermined limiter upper limit value, and the lower limit of the corrected start injection amount is limited to a predetermined limiter lower limit value (FIG. 3, FIG. 6).
The limiter upper limit value and the limiter lower limit value used for the limiter process are variable according to the engine speed and the engine coolant temperature.
In the embodiment of the present invention, the start injection amount upper limit map (indicated as “MAP4 start injection amount upper limit MAP” in FIGS. 3 and 6) 23 and the start injection amount lower limit map (“MAP3 in FIGS. 3 and 6). 24) is stored in the electronic control unit 2 in advance, and the actually acquired engine speed and engine coolant temperature are input, and the start injection is determined according to the magnitude of the input value. The limiter upper limit value is read from the amount upper limit map 23, and the limiter lower limit value is read from the starting injection amount lower limit map 24 (see FIGS. 3 and 6).
In FIG. 3, “MN” means a limiter lower limit value, and “MX” means a limiter upper limit value.

  The corrected starting injection amount calculated in the process of step S116 is set to the limiter upper limit value when the value exceeds the limiter upper limit value, and when the value is less than the limiter lower limit value, When the corrected starting injection amount is within the range between the limiter upper limit value and the limiter lower limit value, the calculated corrected starting injection amount is the starting injection amount. The map 25 is to be written.

  In the specific example of the starting injection amount upper limit map 23 shown in FIG. 6, the numerical values of “0”, “200”, “400”... In the uppermost line are respectively the engine speed (r / min). The numerical values of “−25”, “−15”, “0”, “10”, “20”... In the leftmost column represent the engine coolant temperature. A limiter upper limit value (mg / st) for the corresponding engine speed and engine coolant temperature is set at the position of each grid point on the map.

  Also, in the specific example of the starting injection amount lower limit map 24 shown in FIG. 6, like the specific example of the starting injection amount upper limit map 23, “0”, “200”, “400”. Each numerical value represents the engine speed (r / min), and the numerical values “−25”, “−15”, “0”, “10”, “20”. , Each represents the engine coolant temperature. A limiter lower limit (mg / st) for the corresponding engine speed and engine coolant temperature is set at the position of each grid point on the map.

  After the start injection amount map 25 is updated through the limiter process as described above, for example, necessary processes such as setting various flags required for ending the start mode are executed, and the start mode is ended. Transition to the normal operation mode is performed (see step S122 in FIG. 2).

FIG. 7 shows a specific numerical example of the corrected starting injection amount, which will be described below.
FIG. 7 shows four examples of specific numerical examples in various maps such as the rotation increase time learning map 21 and the reference rotation increase time map 22 described above and specific numerical examples of the corrected starting injection amount after the limiter process. Here, “Example 1” will be described as a representative example, and only the main points will be described for the other examples, and detailed description thereof will be omitted.
The examples in FIG. 7 are numerical examples when the engine speed is 400 (r / min).

In the case of Example 1, first, the rotation increase time t1 (indicated as “MAP1 learning value t1” in FIG. 7) read from the rotation increase time learning map 21 is 0.9 (sec), and the reference rotation increase time map 22 The reference rotation rise time t2 read from (referred to as “MAP2 reference value t2” in FIG. 7) is 1.1 (sec). Therefore, in this case, the rotation increase time correction coefficient (indicated as “correction coefficient = t1 / t2” in FIG. 7) obtained by the process of step S114 is 0.9 ÷ 1.1 = 0.8. (See FIG. 7).
The pre-correction start injection amount read from the start injection amount map 25 (indicated as “MAP5 pre-correction start injection amount” in FIG. 7) is 24 (mg / st), and is determined by the process of step S116. The obtained corrected starting injection amount (indicated as “corrected injection amount before limiter” in FIG. 7) is 24 × (0.9 ÷ 1.1) = 19.6 (see FIG. 7).
In this example, from the starting injection amount upper limit map 23 and the starting injection amount lower limit map 24, as described above, the limiter upper limit value and the limiter lower limit value when the engine speed is 400 (r / min) are respectively The limiter upper limit value (expressed as “MAP3 injection amount upper limit” in FIG. 7) is 31.2 (mg / st), and the limiter lower limit value (expressed as “MAP4 injection amount lower limit” in FIG. 7) is 14. 4 (mg / st) (see FIG. 7).

The corrected starting injection amount after the limiter process is 19.6, and is between the above-described limiter upper limit value and limiter lower limit value. Therefore, the corrected starting injection amount is expressed as “starting injection amount after limiter” in FIG. ) Is written in the starting injection amount map 25.
As a result, in the case of this example 1, in accordance with the fact that the actual rotation increase time t1 is longer than the reference rotation increase time t2, a reduction correction is applied to the starting injection amount before correction, thereby improving the fuel consumption. It has been improved.

Hereinafter, only other points will be described for other examples.
In FIG. 7, in the case of Example 2, as in the case of Example 1, since the rotation increase time t1 <the reference rotation increase time t2, the amount of decrease is corrected. However, the corrected starting injection amount before the limiter process is 19.8 (mg / st), which is a value lower than the limiter lower limit 21.6 (mg / st), so the limiter lower limit 21.6 (mg / st) ) And is written in the starting injection amount map 25.
Further, in the case of Example 3, since the rotation increase time t1> the reference rotation increase time t2, the increase correction is performed. However, since the correction start injection amount is between the limiter upper limit value and the limiter lower limit value, the correction start injection is performed. The amount is written in the starting injection amount map 25. In this case, the start-up time is improved by the increase correction.
Finally, in the case of Example 4, as in the above-described Example 3, since the rotation increase time t1> the reference rotation increase time t2, the increase correction is performed. However, since the corrected starting injection amount exceeds the limiter upper limit value, it is limited to the limiter upper limit value of 124 (mg / st), and this value is written in the starting injection amount map 25 as the corrected starting injection amount.

  This is suitable for a fuel injection control device for an internal combustion engine in which further improvement in engine starting characteristics is desired.

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Electronic control unit 21 ... Rotation rise time learning map 22 ... Reference rotation rise time map 23 ... Start injection amount upper limit map 24 ... Start injection amount lower limit map 25 ... Start injection amount up

Claims (8)

A starting injection amount, which is a target fuel injection amount at the time of starting the internal combustion engine, is obtained based on at least the rotational speed of the internal combustion engine and the cooling water temperature of the internal combustion engine, and the fuel injection to the internal combustion engine is the starting injection amount. A starting injection amount control method for correcting and controlling the starting injection amount in a fuel injection control device configured to be capable of starting injection control by feedback control,
Using the detected rotation speed of the internal combustion engine and the cooling water temperature of the internal combustion engine as input parameters, a start injection amount obtained from a predetermined start injection amount map is determined according to an increase time of the rotation speed of the internal combustion engine. Is corrected by using the rotation increase time correction coefficient to be performed, the starting injection control is performed by the starting injection amount after the correction,
The predetermined start injection amount map is set so as to be able to take out a start injection amount in a predetermined standard internal combustion engine using the rotational speed of the internal combustion engine and the cooling water temperature of the internal combustion engine as input parameters,
The rotation increase time correction coefficient is an increase time of an actual rotation speed in a predetermined rotation speed range of the internal combustion engine with respect to a reference rotation increase time that is a rotation speed increase speed in the predetermined rotation speed range of the standard internal combustion engine. all SANYO determined as a ratio of the rotational rise time is,
The reference rotation rise time is obtained from a preset reference rotation rise time map,
The reference rotation increase time map is set so that a reference rotation increase time is obtained by using a stop time until the start of the internal combustion engine and a cooling water temperature of the internal combustion engine as input parameters, and the reference rotation increase time is determined in advance. The time required to increase the predetermined rotational speed in various combinations of the stop time and the cooling water temperature of the standard internal combustion engine provided,
The rotation rise time is obtained from a rotation rise time learning map,
The rotation increase time learning map is set so that the rotation increase time can be obtained by using the stop time until the start of the internal combustion engine and the cooling water temperature of the internal combustion engine as input parameters. A starting injection amount control method for an internal combustion engine, which is actually acquired as a time required for increasing the rotational speed and is updated as a learning value under a predetermined condition .   2. The start injection amount control method for an internal combustion engine according to claim 1, wherein each time a corrected start injection amount is obtained, the corresponding data in the predetermined start injection amount map is rewritten using the data as a learning value. The predetermined condition for updating the learning value of the rotation rise time learning map is that at least the battery voltage exceeds the predetermined voltage, the outside air temperature exceeds the predetermined temperature, and the atmospheric pressure exceeds the predetermined pressure. The method for controlling the starting injection amount of an internal combustion engine according to claim 2, wherein: A limiter process is performed on the corrected start injection amount so as to be within a range between a predetermined limiter upper limit value and a predetermined limiter lower limit value, and writing to the start injection amount map is enabled after the limiter process. The method for controlling the starting injection amount of an internal combustion engine according to claim 3 . A starting injection amount, which is a target fuel injection amount at the time of starting the internal combustion engine, is obtained based on at least the rotational speed of the internal combustion engine and the cooling water temperature of the internal combustion engine, A fuel injection control device provided with an electronic control unit configured to be capable of executing start injection control by feedback control,
The electronic control unit is
Using the detected rotation speed of the internal combustion engine and the cooling water temperature of the internal combustion engine as input parameters, a start injection amount obtained from a predetermined start injection amount map is determined according to an increase time of the rotation speed of the internal combustion engine. Is corrected by using the rotation increase time correction coefficient to be performed, the starting injection control is performed by the starting injection amount after the correction,
The predetermined start injection amount map is set so as to be able to take out a start injection amount in a predetermined standard internal combustion engine using the rotational speed of the internal combustion engine and the cooling water temperature of the internal combustion engine as input parameters,
The rotation increase time correction coefficient is an increase time of an actual rotation speed in a predetermined rotation speed range of the internal combustion engine with respect to a reference rotation increase time that is a rotation speed increase speed in the predetermined rotation speed range of the standard internal combustion engine. all SANYO determined as a ratio of the rotational rise time is,
Further, the electronic control unit includes:
The reference rotation rise time is determined from a preset reference rotation increase time map, and the rotation increase time is determined from a rotation increase time learning map.
The reference rotation increase time map is set so that a reference rotation increase time is obtained by using a stop time until the start of the internal combustion engine and a cooling water temperature of the internal combustion engine as input parameters, and the reference rotation increase time is determined in advance. The time required to increase the predetermined rotational speed in various combinations of the stop time and the cooling water temperature of the standard internal combustion engine provided,
The rotation increase time learning map is set so that the rotation increase time can be obtained by using the stop time until the start of the internal combustion engine and the cooling water temperature of the internal combustion engine as input parameters. A fuel injection control apparatus, characterized in that it is actually acquired as a time required for increasing the rotational speed and is updated as a learning value under a predetermined condition . The electronic control unit is configured to be able to execute a learning process in which each time a corrected starting injection amount is obtained, it is used as a learning value and rewritten with corresponding data in a predetermined starting injection amount map. The fuel injection control device according to claim 5 . The electronic control unit, at least when the battery voltage exceeds the predetermined voltage, the outside air temperature exceeds the predetermined air temperature, and the atmospheric pressure exceeds the predetermined air pressure, the electronic control unit determines the learning value of the rotation increase time learning map. The fuel injection control device according to claim 6 , wherein the fuel injection control device is configured to perform updating. The electronic control unit performs a limiter process on the corrected starting injection amount so as to be within a range between a predetermined limiter upper limit value and a predetermined limiter lower limit value, and writes the starting injection amount map after the limiter processing. 8. The fuel injection control device according to claim 7 , wherein the fuel injection control device is configured as described above.

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