JP2002235581A - Controller for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stable operating condition by properly correcting a control amount when an internal combustion engine is started in a simplified system configuration without a temperature sensor. SOLUTION: When the internal combustion engine is started, an initial fuel injection amount after starting is calculated by using a post-start fuel injection correction factor FSE estimated based on a history obtained when an engine speed NE is less than a specified engine speed NESTA. The initial fuel injection amount is properly corrected by using the post-start fuel injection correction factor FSE discriminated and updated according to the behavior of the engine speed NE. Thus, even in the simplified system configuration without the temperature sensor, the fuel injection amount of the internal combustion engine after starting can be corrected properly and the stable operating condition can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine for controlling an operation state at the time of starting the internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, when an internal combustion engine is started, in order to control its operation state, for example, a temperature sensor is provided in the internal combustion engine as an operation state detection sensor, and based on the engine temperature detected by the temperature sensor, 2. Description of the Related Art There is known an engine in which a fuel injection amount of an internal combustion engine is corrected.

[0003]

As described above, if the system is configured so that the engine temperature is detected using a temperature sensor, the fuel injection at the time of starting the internal combustion engine is performed based on the amount of change of the temperature sensor. The amount can be corrected appropriately. Here, if the operating state of the internal combustion engine can be known by a simplified system configuration in which the temperature sensor is omitted, a considerable cost reduction can be naturally attained.

[0004] However, conventionally, the temperature sensor is an essential component, and there has been a problem that the fuel injection amount cannot be properly corrected when starting the internal combustion engine without a signal input from the temperature sensor.

Accordingly, the present invention has been made to solve such a problem. In a simplified system configuration having no temperature sensor, the present invention provides a method for starting an internal combustion engine.
It is an object of the present invention to provide a control device for an internal combustion engine that can appropriately correct a control amount and obtain a stable operation state.

[0006]

According to the control device for an internal combustion engine of the first aspect, when the internal combustion engine is started, the initial control amount immediately after the engine speed becomes equal to or higher than a predetermined engine speed is:
The engine speed is estimated based on the history when the engine speed is less than the predetermined engine speed, and the initial control amount at this time is sequentially determined and appropriately corrected according to the subsequent behavior of the engine speed.
Thus, when the internal combustion engine is started, a stable operation state can be obtained by appropriately correcting the control amount after the engine speed becomes equal to or higher than the predetermined engine speed.

In the control apparatus for an internal combustion engine according to the second aspect, the control amount estimating means performs initial control based on the history of the required time when the engine speed is less than the predetermined engine speed, the number of fuel injections, and the total fuel injection amount. The amount is estimated. This stabilizes the operating state of the internal combustion engine immediately after the engine speed becomes equal to or higher than the predetermined engine speed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples.

FIG. 1 is a schematic configuration diagram showing an internal combustion engine to which an internal combustion engine control device according to an embodiment of the present invention is applied and peripheral devices thereof.

In FIG. 1, reference numeral 1 denotes an internal combustion engine (engine).
The air from the air cleaner 3 is introduced into the intake passage 2 of the internal combustion engine 1. A throttle valve 11 which is opened and closed in conjunction with operation of an accelerator pedal (not shown) is provided in the intake passage 2. By opening and closing the throttle valve 11, the amount of intake air (intake air amount) to the intake passage 2 is adjusted. Simultaneously with the intake air amount, the internal combustion engine 1 is provided with an intake passage 2 near the intake port 4.
The fuel is injected and supplied from an injector (fuel injection valve) 5 provided in the fuel cell. Then, an air-fuel mixture composed of a predetermined fuel amount and an intake amount is sucked into the combustion chamber 7 through the intake valve 6.

On the downstream side of the throttle valve 11 provided in the intake passage 2, the intake pressure P in the intake passage 2 is set.
An intake pressure sensor 21 for detecting M is provided. The crankshaft 12 of the internal combustion engine 1 is provided with a crank angle sensor 22 for detecting a crank angle [° CA (Crank Angle)] accompanying the rotation. The internal combustion engine 1 according to the crank angle detected by the crank angle sensor 22
Is calculated.

An ignition plug 13 is provided toward the inside of the combustion chamber 7 of the internal combustion engine 1. The ignition plug 13 receives a high signal from the ignition coil / igniter 14 based on an ignition command signal output from an electronic control unit (ECU) 30 described later in synchronization with the crank angle detected by the crank angle sensor 22. A voltage is applied, and ignition combustion of the air-fuel mixture in the combustion chamber 7 is performed. In this manner, the air-fuel mixture in the combustion chamber 7 is burned (expanded) to obtain a driving force, and the exhaust gas after the combustion is led out of the exhaust manifold through the exhaust valve 8 to the exhaust passage 9 and discharged to the outside. You.

The ECU 30 includes a CPU 31 serving as a central processing unit for executing various known arithmetic processing, a ROM 32 storing a control program, and a RAM 3 storing various data.
3, B / U (backup) RAM 34, input / output circuit 3
5 and a logical operation circuit including a bus line 36 connecting them. This ECU 30 includes:
The intake pressure PM from the intake pressure sensor 21, the crank angle from the crank angle sensor 22, and the like are input. Based on output signals from the ECU 30 based on these various sensor information, the injector 5 related to the fuel injection timing and the fuel injection amount, the ignition coil / igniter 14 related to the ignition timing of the ignition plug 13 and the like are appropriately controlled.

Next, FIG. 2 is a flowchart showing a processing procedure of a post-start fuel injection correction coefficient calculation in the CPU 31 in the ECU 30 used in the control apparatus for an internal combustion engine according to one embodiment of the present invention. This will be described with reference to FIG. Here, FIG. 3 is a time chart showing a transition state of the post-start fuel injection correction coefficient according to the engine speed NE [rpm] of the internal combustion engine 1. Note that this post-start fuel injection correction coefficient calculation routine is performed for each cylinder of the internal combustion engine.
It is repeatedly executed by the CPU 31 for each combustion cycle.

In FIG. 2, first, in step S101,
It is determined whether or not the internal combustion engine 1 has been started. Here, after the internal combustion engine 1 is started, as shown in FIG. 3, when the internal combustion engine 1 is started by cranking an ignition switch (not shown) to “ON”, the engine speed NE becomes the idle speed. The engine speed exceeds a predetermined engine speed NESTA, which is set slightly lower than the engine speed, and the time after time t1 at which it can be considered that the engine has started. On the other hand, when the internal combustion engine 1 is started, as shown in FIG. 3, when the internal combustion engine 1 is started by cranking the ignition switch to “ON”, the engine speed NE becomes a predetermined engine speed NE.
The time from time t0 to time t1 before STA is referred to.

If the condition of step S101 is not satisfied,
That is, when the internal combustion engine 1 is being started, this routine ends without performing any operation. On the other hand, step S101
Is satisfied, that is, when the internal combustion engine 1 has been started, the process proceeds to step S102, and it is determined whether the internal combustion engine 1 has just changed from the start to the post-start (time t1 shown in FIG. 3). You. The determination condition of step S102 is satisfied,
That is, when it is immediately after the internal combustion engine 1 has just started, the process proceeds to step S103, and the starting time, for example, the starting time TST, which is the time required for starting, or the number of fuel injections at the time of starting, in the starting state. Starting fuel injection number NST or the starting fuel injection amount TA which is an integral value of the starting time TST and the starting fuel injection frequency NST.
UAST and the like are calculated.

Next, the process proceeds to step S104, in which the basic fuel injection amount described later is increased and corrected based on the start time TST, the number of injections NST at start, the total fuel injection amount TAUAST at start calculated in step S103. The initial value of the post-start fuel injection correction coefficient FSE is calculated by the following equation (1). Here, A, B, and C are each correction gain.

[0018]

FSE = A × TST + B × NST + C × TAAUAST + (1)

On the other hand, if the determination condition of step S102 is not satisfied, that is, if the internal combustion engine 1 is not immediately after starting but immediately after starting, the post-starting fuel injection correction coefficient FSE has already been set.
Has been calculated, the above-described step S10
Step 3 and step S104 are skipped.

Next, the process proceeds to step S105, where it is determined whether the synchronous injection has been performed. If the determination condition in step S105 is not satisfied, that is, if the synchronous injection has not been performed yet, the routine ends without performing any operation. On the other hand, the determination condition of step S105 is satisfied, that is,
When the synchronous injection is being performed, the process proceeds to step S106, and it is determined whether the engine speed NE at this time is equal to or less than a preset lower limit engine speed D. When the determination condition of step S106 is satisfied, that is, when the engine speed NE is lower than or equal to the lower limit engine speed D (time t1 shown in FIG. 3)
To time t2, time t5 to time t6,.
The routine proceeds to 107, where it is determined that the post-start fuel injection correction coefficient FSE is too small, the predetermined value E is added, and the post-start fuel injection correction coefficient FSE is updated, followed by terminating the present routine.

On the other hand, when the determination condition of step S106 is not satisfied, that is, when the engine speed NE exceeds the lower limit engine speed D and is high (time t3 to time t4 and time t7 shown in FIG. 3).
At time t8,...), The process proceeds to step S108, and it is determined whether the engine speed NE is equal to or higher than a preset upper limit engine speed F. When the determination condition of step S108 is satisfied, that is, when the engine speed NE is higher than or equal to the upper limit engine speed F, the process proceeds to step S109. After the post-fuel injection correction coefficient FSE is updated,
This routine ends.

On the other hand, when the determination condition in step S108 is not satisfied, that is, when the engine speed NE is higher than the lower limit engine speed D and lower than the upper limit engine speed F (from time t2 to time t2 shown in FIG. 3). Time t3, time t4 to time t5, time t6
At time t7,...), The routine proceeds to step S110, where the post-start fuel injection correction coefficient FSE is determined to be appropriate, and the post-start fuel injection correction coefficient FSE at that time is held.
This routine ends.

After the processing of this routine, as is well known in a main routine (not shown), the basic fuel injection amount calculated based on the engine speed NE of the internal combustion engine 1 and the intake pressure PM as a load is calculated as described above. Is increased using the fuel injection correction coefficient FSE after the start, and the fuel injection amount actually injected and supplied from the injector 5 is adjusted.

As described above, the control device for an internal combustion engine according to the present embodiment includes a crank angle sensor 22 as a rotation speed detecting means for detecting the engine rotation speed NE of the internal combustion engine 1 and the engine rotation speed when the internal combustion engine 1 is started. The number NE is a predetermined engine speed NE
A post-start fuel injection correction coefficient FSE for calculating an initial fuel injection amount as an initial control amount immediately after STA or more.
CPU 31 in the ECU 30 for estimating the engine speed NE based on the history when the engine speed NE is lower than the predetermined engine speed NESTA.
And the fuel injection amount as a control amount after the initial control amount estimated by the control amount estimating means is sequentially determined and updated according to the behavior of the engine speed NE. And a control amount correction means which is achieved by the CPU 31 in the ECU 30 for correcting using the post-start fuel injection correction coefficient FSE.

That is, when the internal combustion engine 1 is started, the initial fuel injection amount after the start is calculated by the post-start fuel injection correction coefficient FSE estimated based on the history when the engine speed NE is less than the predetermined engine speed NESTA. The initial fuel injection amount at this time is sequentially determined and updated according to the behavior of the engine speed NE, and the post-start fuel injection correction coefficient FSE is updated.
Is corrected appropriately. As a result, even with a simplified system configuration having no temperature sensor, the fuel injection amount after the start of the internal combustion engine 1 is appropriately corrected, and a stable operating state can be obtained.

The control device E for the internal combustion engine according to this embodiment
The control amount estimating means achieved by the CPU 31 in the CU 30 calculates the post-start fuel injection correction coefficient FSE for calculating the initial fuel injection amount as the initial control amount by setting the engine speed NE to less than the predetermined engine speed NESTA. Is estimated based on the history of the required time, the number of fuel injections, the total amount of fuel injection, and the like at the time of. As described above, the appropriate initial fuel injection amount is estimated based on the history such as the required time, the number of fuel injections, and the total fuel injection amount when the engine speed NE is less than the predetermined engine speed NESTA. It is possible to stabilize the operation state immediately after the start of 1.

In the above-described embodiment, the correction of the fuel injection amount using the post-start fuel injection correction coefficient FSE when starting the internal combustion engine 1 has been described. However, the present invention is not limited to this. Not the other
In a system having an SC (Idle Speed Control) valve, the same operation and effect as in the above-described embodiment can be expected even if the ISC valve opening is corrected.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an internal combustion engine to which an internal combustion engine control device according to an embodiment of the present invention is applied and peripheral devices thereof.

FIG. 2 is a diagram showing a CP in an ECU used in a control device for an internal combustion engine according to an embodiment of the present invention;
9 is a flowchart illustrating a processing procedure of a post-start fuel injection correction coefficient calculation in U.

FIG. 3 is a time chart showing a transition state of a post-start fuel injection correction coefficient corresponding to the processing of FIG. 2;

[Explanation of symbols]

 Reference Signs List 1 internal combustion engine 21 intake pressure sensor 22 crank angle sensor 30 ECU (electronic control unit)

Claims (2)

[Claims] 1. An engine speed detecting means for detecting an engine speed of an internal combustion engine, wherein an initial control amount immediately after the engine speed becomes equal to or higher than a predetermined engine speed at the time of starting the internal combustion engine, Control amount estimating means for estimating based on the history when the rotational speed is less than the predetermined engine rotational speed, and controlling the control amount after the initial control amount estimated by the control amount estimating means to the behavior of the engine rotational speed. Sequentially according to
A control device for an internal combustion engine, comprising: control amount correction means for determining and correcting. 2. The control amount estimating means stores the initial control amount in a history of at least one of time required when the engine speed is less than the predetermined engine speed, fuel injection frequency, and total fuel injection amount. The control device for an internal combustion engine according to claim 1, wherein the estimation is performed based on: