JP3900002B2 - Fuel injection control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides an internal combustion engine that immediately supplies a fuel injection amount in response to a change in throttle opening caused by a driver's acceleration request, in addition to supplying a fuel injection amount for each predetermined crank angle to each cylinder of the internal combustion engine configured by independent intake. The present invention relates to a fuel injection control apparatus.
[0002]
[Prior art]
Conventionally, in relation to a fuel injection control device for an internal combustion engine, in addition to the synchronous injection control for supplying the fuel injection amount for each predetermined crank angle to each cylinder of the internal combustion engine composed of independent intake, the throttle opening by the driver's acceleration request One that performs asynchronous injection control that immediately supplies a fuel injection amount in response to a change is known.
[0003]
[Problems to be solved by the invention]
By the way, when performing asynchronous injection control in addition to synchronous injection control as described above, the fuel injection amount is set in accordance with the throttle opening change caused by the driver's acceleration request, and this fuel injection amount is set in the internal combustion engine. Corrections are made according to various parameters in the operating state.
[0004]
Here, as shown in FIG. 5, in an internal combustion engine composed of independent intake air, even if the amount of change in the throttle opening, the engine speed, the load, etc. as various parameters representing the operating state are the same, the change in the throttle opening The intake pressure in the intake passage at the timing of occurrence of the intake, that is, the asynchronous injection timing (time t02 or time t03) varies greatly and differs. However, in the prior art, as shown in FIG. 5, the pulse width corresponding to the asynchronous injection timing among the injector pulses to the injector (fuel injection valve) (the broken line in FIG. The fuel injection time indicated by is set to be the same. Then, under the influence of the intake pressure at the asynchronous injection timing, the fuel injection amount in the actual asynchronous injection fluctuates, and as a result, there is a problem that the behavior of the internal combustion engine becomes unstable.
[0005]
Therefore, the present invention has been made to solve such a problem, and in addition to the synchronous injection control, the fuel injection amount when performing the asynchronous injection control is appropriately set according to the operating state of the internal combustion engine. An object of the present invention is to provide a fuel injection control device for an internal combustion engine capable of stabilizing the behavior.
[0006]
[Means for Solving the Problems]
According to the fuel injection control device for an internal combustion engine of claim 1, the fuel injection amount by the synchronous injection control for each predetermined crank angle of each cylinder of the internal combustion engine is supplied by the synchronous injection control means, and further, the throttle opening detection means When a change in the throttle opening is detected, the fuel injection amount corrected based on the correction coefficient calculated according to the intake pressure at this time detected by the intake pressure detection means as the asynchronous injection control is output by the asynchronous injection control means. Supplied immediately. According to such asynchronous injection control, a suitable fuel injection amount that responds quickly to the driver's acceleration request is supplied, and the behavior of the internal combustion engine is stabilized.
[0007]
According to the fuel injection control device of the internal combustion engine of claim 2, the fuel injection amount by the synchronous injection control for each predetermined crank angle of each cylinder of the internal combustion engine is supplied by the synchronous injection control means, and further, the throttle opening degree detection means When a change in the throttle opening is detected, the crank angle at which the fuel injection amount corrected based on the correction coefficient corresponding to the intake pressure estimated by the various parameters at this time as asynchronous injection control differs from that of the synchronous injection by the asynchronous injection control means. Supplied at According to such asynchronous injection control, a suitable fuel injection amount adapted to the driver's acceleration request is supplied without detecting the actual intake pressure, and the behavior of the internal combustion engine is stabilized.
[0008]
In the asynchronous injection control means in the fuel injection control apparatus for an internal combustion engine according to claim 3, the correction coefficient corresponding to the intake pressure for correcting the charge injection amount in the asynchronous injection by a map having at least the throttle opening and the engine speed as parameters. Calculated. As a result, it is possible to obtain an effect that the number of adaptation man-hours for estimating the correction coefficient corresponding to the intake pressure is small and the calculation load in the asynchronous injection control is reduced.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples.
[0010]
<Example 1>
FIG. 1 is a schematic configuration diagram showing an internal combustion engine to which a fuel injection control device for an internal combustion engine according to a first example of an embodiment of the present invention is applied and its peripheral devices.
[0011]
In FIG. 1, reference numeral 1 denotes an internal combustion engine (independent intake engine) that supplies an intake air amount (intake air amount) independently for each cylinder. Air from an air cleaner 3 is introduced into an intake passage 2 of the internal combustion engine 1. The A throttle valve 11 that is opened and closed in conjunction with an operation of an accelerator pedal (not shown) as a driver (driver) request is disposed in the middle of the intake passage 2. When the throttle valve 11 is opened and closed, the amount of intake air to the intake passage 2 is adjusted. At the same time as the intake air amount, the fuel pressure-fed by a fuel pump (not shown) and regulated by the pressure regulator 12 is disposed in the intake passage 2 in the vicinity of the intake port 4 of the internal combustion engine 1. Injection is supplied from an injector (fuel injection valve) 5. Then, an air-fuel mixture having a predetermined fuel amount and intake air amount is sucked into the combustion chamber 7 via the intake valve 6.
[0012]
A throttle opening sensor 21 for detecting a throttle opening degree TA corresponding to an accelerator pedal depression amount or the like is disposed in the throttle valve 11 in the intake passage 2. An intake pressure sensor 22 that detects the intake pressure PM in the intake passage 2 is disposed on the downstream side of the throttle valve 11. The internal combustion engine 1 is provided with a water temperature sensor 23 for detecting the cooling water temperature THW. Further, a crank angle sensor 24 for detecting a crank angle [° CA (Crank Angle)] accompanying the rotation is disposed on the crankshaft 13 of the internal combustion engine 1. Based on the crank angle detected by the crank angle sensor 24, the engine speed NE of the internal combustion engine 1 is calculated.
[0013]
A spark plug 14 is disposed toward the combustion chamber 7 of the internal combustion engine 1. The ignition plug 14 has a high voltage from an ignition coil / igniter 15 based on an ignition command signal output from an ECU (Electronic Control Unit) 30 described later in synchronization with a crank angle detected by a crank angle sensor 24. A voltage is applied, and ignition combustion is performed on the air-fuel mixture in the combustion chamber 7. In this way, the air-fuel mixture in the combustion chamber 7 is combusted (expanded) to obtain driving force, and the exhaust gas after combustion is led out from the exhaust manifold to the exhaust passage 9 via the exhaust valve 8 and discharged to the outside. The
[0014]
The ECU 30 includes a CPU 31 as a central processing unit that executes various known arithmetic processes, a ROM 32 that stores control programs, a RAM 33 that stores various data, a B / U (backup) RAM 34, an input / output circuit 35, and a bus connecting them. It is configured as a logical operation circuit composed of lines 36 and the like. The ECU 30 receives the throttle opening TA from the throttle opening sensor 21, the intake pressure PM from the intake pressure sensor 22, the cooling water temperature THW from the water temperature sensor 23, the engine speed NE from the crank angle sensor 24, and the like. ing. Based on the 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 spark plug 14 related to the ignition timing, the ignition coil / igniter 15 and the like are appropriately controlled.
[0015]
Next, a flowchart of FIG. 2 showing a processing procedure of correction coefficient calculation for asynchronous injection in the CPU 31 in the ECU 30 used in the fuel injection control device for an internal combustion engine according to an example of the embodiment of the present invention. Based on FIG. 3, it demonstrates. Here, FIG. 3 is a time chart showing transition states of various sensor signals and various control amounts corresponding to the processing of FIG. In the injector pulse of FIG. 3, synchronous injection is indicated by a solid line, and asynchronous injection is indicated by a broken line. This correction coefficient calculation routine is repeatedly executed by the CPU 31 every predetermined time.
[0016]
In FIG. 2, in step S101, it is determined whether there is an asynchronous injection request. When the determination condition of step S101 is satisfied, that is, when it is determined that there is a request for asynchronous injection based on the amount of change in the throttle opening TA according to the accelerator pedal depression amount or the like due to the driver's acceleration request (time t2 shown in FIG. 3 and At time t3), the process proceeds to step S102. In step S102, the intake pressure PM from the intake pressure sensor 22 is read. Next, the process proceeds to step S103, and a correction coefficient for correcting the basic fuel injection amount in the asynchronous injection based on the intake pressure PM read in step S102 is a one-dimensional table (not shown) using the intake pressure PM as a parameter. Calculated by the interpolation operation, and this routine ends.
[0017]
On the other hand, when the determination condition of step S101 is not satisfied, that is, when there is no request for asynchronous injection, this routine is terminated without doing anything. The final fuel injection amount is calculated by multiplying the correction coefficient obtained by the above routine by the basic fuel injection amount in the asynchronous injection. The injector 5 is driven by an injector pulse corresponding to this fuel injection amount (a fuel injection time that varies depending on the intake pressure PM indicated by a broken line in FIG. 3), so that the operating conditions are the same even when the asynchronous injection timing is different. If so, the same amount of fuel injection is supplied, and suitable asynchronous injection is achieved. In addition, when the injector pulse corresponding to the fuel injection amount in the asynchronous injection control overlaps with the injector pulse corresponding to the fuel injection amount in the synchronous injection control, the injector pulse amount in the asynchronous injection control is subsequent to the injector pulse in the synchronous injection control. Extended.
[0018]
As described above, the fuel injection control device for the internal combustion engine of the present embodiment provides the throttle opening of the throttle valve 11 disposed in the intake passage 2 so as to supply the intake air amount independently for each cylinder of the internal combustion engine 1. A throttle opening degree sensor 21 as a throttle opening degree detecting means for detecting TA, an intake pressure sensor 22 as an intake pressure detection means for detecting an intake pressure PM in the intake passage 2 downstream of the throttle valve 11, and the internal combustion engine 1 When there is a change in the throttle opening TA due to the driver's acceleration request and the synchronous injection control means achieved by the injector 5 and the ECU 30 for supplying the fuel injection amount for each predetermined crank angle of each of the cylinders, and the intake pressure PM as a parameter Asynchronous injection control achieved by the injector 5 and the ECU 30 that immediately supply the corrected fuel injection amount based on the correction coefficient It is intended to include a door.
[0019]
That is, if there is a change in the throttle opening TA in addition to the fuel injection amount by the synchronous injection control for each predetermined crank angle of each cylinder of the internal combustion engine 1, the one-dimensional table is used as the asynchronous injection control according to the intake pressure PM at this time. The fuel injection amount corrected based on the calculated correction coefficient is immediately supplied from the injector 5. According to such asynchronous injection control, a suitable fuel injection amount that immediately responds to the driver's acceleration request is supplied, and the behavior of the internal combustion engine 1 at this time can be stabilized.
[0020]
<Example 2>
FIG. 4 is a flowchart showing a processing procedure of correction coefficient calculation for asynchronous injection in the CPU 31 in the ECU 30 used in the fuel injection control device of the internal combustion engine according to the second example of the embodiment of the present invention. This correction coefficient calculation routine is repeatedly executed by the CPU 31 every predetermined time. Here, an internal combustion engine to which the fuel injection control device for an internal combustion engine according to the second example of the embodiment of the present invention and its peripheral devices are shown in FIG. In FIG. 4, since the intake air pressure sensor 22 is omitted, the detailed description thereof is omitted.
[0021]
In FIG. 4, in step S201, it is determined whether there is an asynchronous injection request. When the determination condition of step S201 is satisfied, that is, when it is determined that there is a request for asynchronous injection based on the amount of change in the throttle opening TA according to the accelerator pedal depression amount or the like due to the driver's acceleration request, the routine proceeds to step S202. In step S202, it is determined whether it is asynchronous injection timing. When the determination condition of step S202 is satisfied, that is, when the crank angle is an appropriate asynchronous injection timing that does not overlap with the synchronous injection timing, the routine proceeds to step S203, where the throttle opening degree TA and the crank angle sensor from the throttle opening degree sensor 21 are transferred. The engine speed NE by 24 is read.
[0022]
Next, the routine proceeds to step S204, where the correction coefficient for correcting the basic fuel injection amount in the asynchronous injection based on the throttle opening TA and the engine rotational speed NE read in step S203 is the throttle opening TA and the engine rotational speed. Calculation is performed by interpolation using a two-dimensional map (not shown) using NE as a parameter, and this routine is terminated. On the other hand, when the determination condition of step S201 is not satisfied, that is, when there is no request for asynchronous injection, or when the determination condition of step S202 is not satisfied, that is, when the crank angle is inappropriate as the asynchronous injection timing, nothing is done. This routine is terminated without doing so. The final fuel injection amount is calculated by multiplying the correction coefficient obtained by the above routine by the basic fuel injection amount in the asynchronous injection. The injector 5 is driven by an injector pulse (fuel injection time) corresponding to the fuel injection amount, and a suitable asynchronous injection is achieved.
[0023]
As described above, the fuel injection control device for the internal combustion engine of the present embodiment provides the throttle opening of the throttle valve 11 disposed in the intake passage 2 so as to supply the intake air amount independently for each cylinder of the internal combustion engine 1. A throttle opening degree sensor 21 serving as a throttle opening degree detecting means for detecting TA; a synchronous injection control means achieved by an injector 5 and an ECU 30 for supplying a fuel injection amount for each predetermined crank angle of each cylinder of the internal combustion engine 1; When there is a change in the throttle opening TA due to the driver's acceleration request, the injector 5 supplies the fuel injection amount corrected based on the correction coefficient corresponding to the intake pressure estimated by various parameters at a crank angle different from that of the synchronous injection, and Asynchronous injection control means achieved by the ECU 30.
[0024]
That is, if there is a change in the throttle opening TA in addition to the fuel injection amount by the synchronous injection control for each predetermined crank angle of each cylinder of the internal combustion engine 1, the intake pressure estimated according to the various parameters at this time as asynchronous injection control The fuel injection amount corrected based on a considerable correction coefficient is supplied from the injector 5 at a crank angle different from that of the synchronous injection. According to such asynchronous injection control, a suitable fuel injection amount adapted to the driver's acceleration request is supplied without detecting the actual intake pressure, and the behavior of the internal combustion engine 1 at this time is stabilized. Can do.
[0025]
Further, the asynchronous injection control means achieved by the injector 5 and the ECU 30 of the fuel injection control device for the internal combustion engine of the present embodiment is based on a two-dimensional map (not shown) using the throttle opening TA and the engine rotational speed NE as parameters. A correction coefficient is calculated. That is, a correction coefficient corresponding to the intake pressure for correcting the charge injection amount in the asynchronous injection is estimated and calculated on the two-dimensional map according to the throttle opening TA and the engine speed NE at this time. As a result, the number of matching man-hours for estimating the correction coefficient corresponding to the intake pressure is small, and the calculation load in the asynchronous injection control of the ECU 30 can be reduced.
[0026]
In the above embodiment, the asynchronous injection in one cylinder among the plurality of cylinders is described as the internal combustion engine 1 composed of independent cylinders. However, the present invention is not limited to this and is not limited to this. Since an internal combustion engine composed of cylinders is of course an independent cylinder, similar asynchronous injection control can be performed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an internal combustion engine to which a fuel injection control device for an internal combustion engine according to a first example of an embodiment of the invention is applied and its peripheral devices.
FIG. 2 shows a correction coefficient calculation processing procedure for asynchronous injection in a CPU in an ECU used in the fuel injection control device for an internal combustion engine according to the first example of the embodiment of the present invention; It is a flowchart.
FIG. 3 is a time chart showing transition states of various sensor signals and various control amounts corresponding to the processing of FIG. 2;
FIG. 4 shows a correction coefficient calculation processing procedure for asynchronous injection in a CPU in an ECU used in a fuel injection control device for an internal combustion engine according to a second example of an embodiment of the present invention; It is a flowchart.
FIG. 5 is a time chart showing transition states of various sensor signals and various control amounts corresponding to synchronous injection and asynchronous injection in a conventional fuel injection control device for an internal combustion engine.
[Explanation of symbols]
1 Internal combustion engine 2 Intake passage 5 Injector (fuel injection valve)
11 Throttle valve 21 Throttle opening sensor 22 Intake pressure sensor 24 Crank angle sensor 30 ECU (electronic control unit)

Claims (3)

Throttle opening degree detecting means for detecting the throttle opening degree of a throttle valve disposed in the middle of the intake passage so as to supply the intake amount independently for each cylinder of the internal combustion engine;
An intake pressure detecting means for detecting an intake pressure in the intake passage on the downstream side of the throttle valve;
Synchronous injection control means for supplying a fuel injection amount for each predetermined crank angle of each cylinder of the internal combustion engine;
When there is a change in the throttle opening due to the driver's acceleration request, there is provided an asynchronous injection control means for immediately supplying a fuel injection amount corrected based on a correction coefficient using the intake pressure when the opening change occurs as a parameter. A fuel injection control device for an internal combustion engine. Throttle opening degree detecting means for detecting the throttle opening degree of a throttle valve disposed in the middle of the intake passage so as to supply the intake amount independently for each cylinder of the internal combustion engine;
Synchronous injection control means for supplying a fuel injection amount for each predetermined crank angle of each cylinder of the internal combustion engine;
When there is a change in the throttle opening due to the driver's acceleration request, the fuel injection amount corrected based on the correction coefficient equivalent to the intake pressure when the opening change occurs, which is estimated by various parameters, is different from the synchronous injection. A fuel injection control device for an internal combustion engine, comprising: an asynchronous injection control means for supplying at a crank angle. The fuel injection control device for an internal combustion engine according to claim 2, wherein the asynchronous injection control means calculates the correction coefficient from a map using at least the throttle opening and the engine speed as parameters.

Images