JPH03229940A - Fuel injection quantity control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent acceleration shock always stably by judging the nonsynchronous injection timing in the intake stroke of each cylinder on the basis of the crank position of an internal combustion engine at the acceleration starting time of the internal combustion engine so as to correct the nonsynchronous injection quantity. CONSTITUTION:A fuel injection valve M2 in each cylinder of an internal combustion engine M1 is controlled by a means M5 so as to perform synchronous and nonsynchronous injection in each cylinder at the acceleration starting time judged by a means M4 on the basis of the operating state detected by a means M3. In such a device, the crank position of the internal combustion engine M1 is detected by a means M6. Also at the acceleration starting time, the nonsynchronous injection timing in the intake stroke of each cylinder is judged by a means M7 on the basis of the crank position. At this nonsynchronous injection timing, the nonsynchronous injection quantity from the means M2 controlled by a means M5 is corrected by a means M8. Acceleration shock caused by the nonsynchronous injection can be therefore performed always stably.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fuel injection amount control device for an internal combustion engine, and more specifically, in addition to synchronous injection in each cylinder at the start of acceleration of the internal combustion engine, a predetermined amount of asynchronous injection is also provided. The present invention relates to a fuel injection amount control device for an internal combustion engine that performs injection.

[Prior Art] Conventionally, as fuel injection amount control for an internal combustion engine, it has been proposed to execute a predetermined amount of asynchronous injection during normal acceleration or during acceleration from a fuel cut state.

For example, in Japanese Patent Application Laid-Open No. 60-201046, when acceleration is detected in the normal synchronous injection operating state,
Performs asynchronous injection to supply fuel only to cylinders at the crank position after synchronous injection until the end of the intake stroke,
It was designed to prevent acceleration shock.

[Problems to be Solved by the Invention] However, in the case of the conventional example, as the intake stroke at the start of acceleration approaches the end, the amount of fuel actually taken into the combustion chamber out of the asynchronously injected fuel decreases. It had become.

In other words, as shown in Figure 8(a), if acceleration is started and asynchronous injection is performed just before or after the intake valve opens, all of the injected fuel at that time is transferred to the combustion chamber. When it is inhaled, it explodes and burns in just the right amount, preventing acceleration shock. However, as shown in Fig. 8(b), if asynchronous injection is performed after a while after the intake valve opens, or as shown in Fig. 8(b),
As shown in C), if asynchronous injection is performed just before the intake valve closes, not all of the amount of fuel injected at that time will be sucked into the combustion chamber, so even though asynchronous injection was performed, acceleration shock will occur. There was a risk that they would not be able to deal with the situation.

This is due to the fact that a fixed amount of asynchronous injection is always performed during the intake stroke, regardless of whether the asynchronous injection timing is early or late, and the closer the asynchronous injection timing is to the end of the intake stroke, the leaner the air-fuel ratio becomes. This was due to the fact that the

This invention was made in view of the above-mentioned circumstances, and its purpose is to always and stably prevent acceleration shock due to asynchronous injection according to whether the asynchronous injection timing is late or early during the intake stroke. An object of the present invention is to provide a fuel injection amount control device for an internal combustion engine.

[Means for Solving the Problem] In order to achieve the above object, the present invention has the following features:
As shown in the figure, a fuel injection means M2 provided in each cylinder of the internal combustion engine M1, an operating state detecting means M3 for detecting the operating state of the internal combustion engine M1, and a detection value of the operating state detecting means M3 are used. Acceleration start determining means M4 determines whether the internal combustion engine M1 has started accelerating, and when the acceleration start determining means M4 determines that the internal combustion engine M1 has started accelerating, it performs synchronous injection in each cylinder in conjunction with the start of acceleration. A fuel injection amount control device for an internal combustion engine includes an asynchronous injection control means M5 that controls each fuel injection means M2 to perform quantitative asynchronous injection, and a crank position detection means M6 that detects the crank position of the internal combustion engine M1. , acceleration start judgment means M4
an asynchronous injection timing determining means M7 that determines the asynchronous injection timing during the intake stroke of each cylinder based on the detected value of the crank position detecting means M6 when it is determined that the acceleration of the internal combustion engine M1 has started; The asynchronous injection amount correction means M8 corrects the asynchronous injection amount from each fuel injection means M2 under the control of the asynchronous injection control means M5 in accordance with the determination result of the means M7.

[Operations] According to this invention, as shown in FIG.
During operation of the internal combustion engine M, the operating state detection means M3 detects that the internal combustion engine
The acceleration start determining means M4 detects the operating state of the internal combustion engine M1 based on the detected value of the operating state detecting means M3.
It is determined whether or not acceleration has started. When the acceleration start determining means M4 determines that the internal combustion engine M1 is to start accelerating, the asynchronous injection control means M5 performs a predetermined amount of asynchronous injection in each cylinder in addition to the simultaneous injection in accordance with the start of acceleration. For this purpose, each fuel injection means M2 is controlled.

At this time, the crank position detecting means M6 detects the crank position which changes periodically during operation of the internal combustion engine Ml, and the asynchronous injection timing determining means M7 detects each cylinder based on the detected value of the crank position detecting means M6. Determine the timing of asynchronous injection during the intake stroke. In other words, it is determined at which time during the intake stroke the asynchronous injection is being performed.

Then, the asynchronous injection amount correction means M8 controls each fuel under the control of the asynchronous injection control means M5 in accordance with the judgment result of the asynchronous injection timing judgment means M7, that is, in response to whether the asynchronous injection timing is early or late during the intake stroke. Correct the asynchronous injection amount from the injection means M2.

Therefore, the asynchronous injection amount is adjusted according to whether the asynchronous injection timing is late or early, and a sufficient amount of fuel is sucked into the combustion chamber according to the timing.

[Example] Hereinafter, an example embodying the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram showing a schematic configuration of a gasoline engine system to which the fuel injection amount control device for an internal combustion engine of the present invention is applied. An engine 1 serving as an internal combustion engine takes in outside air from an air cleaner 3 via an intake passage 2. Also, at the same time as the outside air is taken in, the engine l is installed in each cylinder (in this case, cylinder #1, cylinder #2, cylinder #3, cylinder #4, a total of 4 cylinders) near the intake port 1a. The fuel injected from an injector 4 as a fuel injection means is taken in. Then, the mixture of the taken in fuel and outside air is introduced into the combustion chamber 1b through the intake valve 5a provided for each cylinder #l to #4, and is exploded and combusted in the combustion chamber lb to drive the engine. After obtaining the force, the exhaust gas is led out through the exhaust valve 5b to the exhaust passage 6 where the exhaust manifolds for each cylinder #1 to #4 are assembled, and is discharged to the outside.

A throttle valve 7 is provided in the middle of the intake passage 2 and is opened and closed in conjunction with the operation of an accelerator pedal (not shown). By opening and closing the throttle valve 7, the amount of air taken into the intake passage 2 is adjusted.

Furthermore, a surge tank 8 is provided downstream of the throttle valve 7 to smooth out pulsations in the intake air.

An intake temperature sensor 21 is provided in the intake passage 2 near the air cleaner 3 to detect intake air temperature. or,
A throttle sensor 22 is provided near the throttle valve 7 to detect its opening degree. Furthermore, the surge tank 8 is connected to the same tank 8 to receive suction pressure (intake pressure).
An intake pressure sensor 23 is provided to detect PM. In this embodiment, the throttle sensor 22 and the intake pressure sensor 23 constitute operating state detection means for detecting the operating state of the engine I.

On the other hand, an oxygen sensor 24 is provided in the middle of the exhaust passage 6 to detect the oxygen concentration in the exhaust gas.

Further, the engine l is provided with a water temperature sensor 25 that detects the temperature of its cooling water.

An ignition signal distributed by a distributor 10 is applied to spark plugs 9 provided for each cylinder #1 to #4 of the engine l. The distributor IO is for distributing the high voltage output from the igniter 11 to each spark plug 9 in synchronization with the crank angle of the engine 1, and the ignition timing of each spark plug 9 is the high voltage output timing from the igniter 11. Determined by

The distributor 10 has the same distributor 1.
From the rotation of the rotor (not shown) at 0 to the rotation speed of the engine l (
A rotation speed sensor 26 for detecting the engine rotation speed (NE) and a cylinder discrimination sensor 27 as a crank position detection means for detecting changes in the crank angle of the engine 1 at a predetermined rate according to the rotation of the rotor are respectively installed. ing. In this embodiment, assuming that the engine 1 rotates twice per stroke, the cylinder discrimination sensor 27 detects the crank angle at a rate of 30° CA.

Each injector 4 and igniter 11 is connected to an electronic control device (
(hereinafter simply referred to as rEcUJ) 28,
Their drive timings are controlled by the operation of the ECU 28. This ECU 28 includes an intake air temperature sensor 21.
A throttle sensor 22, an intake pressure sensor 23, an oxygen sensor 24, a water temperature sensor 25, a rotation speed sensor 26, and a cylinder discrimination sensor 27 are respectively connected. Therefore, E.C.U.
2B suitably controls the injector 4 and the igniter 11 based on the output signals from these sensors 21 to 27.

Next, the configuration of the ECU 28 will be explained according to the block diagram of FIG. 3. The ECU 28 is a central processing device (CPU) 31, a read-only memory (ROM) 32 in which predetermined control programs, etc. are stored, and a CPU 31.
Random access memory that temporarily stores calculation results, etc.
RAM) 33, backup RAM 34 for storing pre-stored data, these parts and external input circuit 35
, an external output circuit 36, etc., are connected to each other via a bus 37.

The external input circuit 35 includes the aforementioned intake temperature sensor 21, throttle sensor 22, intake pressure sensor 23, and oxygen sensor 2.
4, a water temperature sensor 25, a rotational speed sensor 26, a cylinder discrimination sensor 27, etc. are connected to the engine. And the CPU
31 reads signals outputted from each sensor 21 to 27 as input values via an external input circuit 35.

Further, the CPU 31 controls the injector 4 and igniter 11 connected to the external output circuit 36 based on these input values.
to suitably control.

Next, among the fuel injection amount control executed by the ECU 28, the asynchronous injection control process in particular will be explained according to the flowchart shown in FIG.

Incidentally, this flowchart represents a routine for asynchronous injection amount control performed during operation of the engine 1 among various processes executed by the ECU 28, and is executed by a regular interrupt every predetermined time.

When the process moves to this routine, first step 101
At , it is determined whether or not acceleration has started. That is, the detected values from the throttle sensor 22 and the intake pressure sensor 23 are read, the throttle change amount ΔTA and the intake pressure change amount PM are calculated based on the read values, and sudden acceleration and re-start are determined based on the magnitude of the calculation results. Determines the start of acceleration, etc. If acceleration has not started, there is no need to perform asynchronous injection, and the subsequent processing is temporarily terminated. On the other hand, if acceleration has started, the process moves to the next step 102 to execute asynchronous injection.

Then, in step 102, the asynchronous injection amount, ie, the asynchronous injection time, for executing the asynchronous injection is determined. This asynchronous injection time is a time that is predetermined depending on whether the re-acceleration is from when fuel power is activated or the acceleration is from another type of acceleration.

Next, in step 103, the current crank position is determined. That is, the detected value from the cylinder discrimination sensor 27 is read, and the current crank angle (position) is determined based on the read value.

Subsequently, in step 104, the step 103
Based on the crank angle determined in , the correction coefficient for the asynchronous injection time is searched from the map shown in FIG. This map predetermines the correction coefficient for the crank angle according to the period during which the intake valves 5a of each cylinder #l to #4 are open, that is, the intake stroke of each cylinder #1 to #4. The correction coefficient is set to increase as the intake strokes #1 to #4 approach the end, and are stored in the ROM 32 in advance.

Further, in step 105, a corrected asynchronous injection amount (corrected asynchronous injection time) is calculated from the asynchronous injection amount, that is, the asynchronous injection time determined in step 102, and the correction coefficient 3 found in step 104.

Then, in step 106, the step 105
Based on the corrected asynchronous injection time calculated in
The #4 injector 4 is simultaneously driven and controlled, that is, the asynchronous injection is executed by simultaneously injecting all cylinders #1 to #4, and the subsequent processing is temporarily terminated.

Therefore, when asynchronous injection is executed in response to sudden acceleration or re-acceleration during operation of the engine 1, for example, as shown in FIG.
If the crank angle is immediately before or after the intake valve 5a opens, then the asynchronous injection time tl
remains at the standard time, and all the injected fuel is sucked into the combustion chamber 1b in just the right amount and is subjected to explosion and combustion, thereby making it possible to prevent acceleration shock.

On the other hand, as shown in FIG. 6(b), if some time has passed since the intake valves 5a of cylinders #1 to #4 in which the asynchronous injection timing is opened, or 4 is shown in FIG. 6(c). As shown, when the intake valves 5a of cylinders #1 to #4 with asynchronous injection timing are about to close, the asynchronous injection time t2゜t3 at that time becomes longer as the intake stroke ends, and the intake valve 5a is about to close. Even just before the valve 5a closes, the amount of fuel actually drawn into the combustion chamber 1b can be increased, and a sufficient amount of fuel can be exploded and combusted.

In other words, in this embodiment, unlike the conventional example in which a constant amount of asynchronous injection is always performed regardless of whether the asynchronous injection timing during the intake stroke is late or early, the asynchronous injection time t1 to t3 increases as the end of the intake stroke approaches. In other words, the amount of asynchronous injection increases, and asynchronous injection is performed until the intake valve 5a is closed, so that a sufficient amount of fuel can be supplied to the combustion chamber 1b, and it is possible to cope with a lean air-fuel ratio.

As a result, acceleration shock due to asynchronous injection can be always reliably and stably prevented by combining the timing of the asynchronous injection during the intake stroke with a later or earlier timing.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and may be implemented as follows by changing a part of the structure as appropriate without departing from the spirit of the invention.

(1) In the above embodiment, the map for correcting the asynchronous injection amount is such that the correction coefficient increases as the intake stroke of each cylinder #1 to #4 approaches the end, as shown in FIG. A map was set up, but as shown by the solid line in Figure 7,
The correction coefficient may be gradually increased until the latter half of the intake stroke of each cylinder #1 to #4, and thereafter the correction coefficient may be gradually decreased as the intake stroke approaches the end.

This map shows that when asynchronous injection is performed in all cylinders #1 to #4 at the same time, the air-fuel ratio becomes overrich in the subsequent intake stroke in other cylinders that do not correspond to the intake stroke, resulting in poor drivability. This setting was made in consideration of the compromise between deterioration of the air-fuel ratio and the generation of acceleration shock due to lean air-fuel ratio. Therefore, acceleration shock in asynchronous injection can be more appropriately prevented.

(2) In the above embodiment, when the acceleration starts, the asynchronous injection is carried out simultaneously in the golden cylinders 6 #1 to #4, but only the cylinders in which the intake stroke is performed when the acceleration starts are specified. However, it may be implemented in a case where asynchronous injection is performed independently only for the specified cylinder.

(3) In the embodiment described above, the start of acceleration was determined based on the detected values from the throttle sensor 22 and the intake pressure sensor 23, but the acceleration was determined based on the detected value from only either the throttle sensor 22 or the intake pressure sensor 23. You may decide to start.

[Effects of the Invention] As described in detail above, according to the present invention, when the acceleration start determining means determines that the internal combustion engine has started accelerating, the asynchronous injection timing determining means performs each injection timing based on the detected value of the crank position detecting means. The asynchronous injection timing during the intake stroke of the cylinder is determined, and the asynchronous injection amount correction means corrects the asynchronous injection amount from each fuel injection means under the control of the asynchronous injection control means in accordance with the determination result. The asynchronous injection amount can be adjusted according to whether the asynchronous injection timing is late or early during the intake stroke, and it has the excellent effect of always stably preventing acceleration shock caused by asynchronous injection.

[Brief explanation of drawings]

Figure 1 is a diagram showing the basic configuration of this invention, Figures 2 to 6
The figure shows an embodiment embodying this invention,
FIG. 2 is a diagram showing a schematic configuration of a gasoline engine system to which a fuel injection amount control device for an internal combustion engine is applied, and FIG. 3 is a block diagram showing an electrical configuration of the fuel injection amount control device.
FIG. 4 is a flowchart explaining the asynchronous injection control process executed by the fuel injection amount control device, FIG. 5 is a map showing correction coefficients for the crank angle corresponding to the intake stroke of each cylinder, and FIG. It is a time chart explaining the difference of asynchronous injection time with respect to asynchronous injection timing. 7th
The figure is a map showing the correction coefficient for the crank angle corresponding to the intake stroke of each cylinder in another embodiment embodying the present invention, and Fig. 8 is a time chart illustrating the asynchronous injection time for the asynchronous injection timing in the conventional example. It is a chart. 8 In the figure, Ml is an internal combustion engine, M2 is a fuel injection means, M3 is an operating state detection means, M4 is an acceleration start judgment means, M5 is an asynchronous injection control means, M6 is a crank position detection means, and Ml is an asynchronous injection timing judgment means. , M8 is an asynchronous injection amount correction means, 1 is an engine as an internal combustion engine, 4 is an injector as a fuel injection means, 22 is a throttle sensor, 23 is an intake pressure sensor (22 and 23 constitute an operating state detection means) ), 27 is a cylinder discrimination sensor as a crank position detection means, 28 is an ECU that constitutes an acceleration start judgment means, an asynchronous injection control means, an asynchronous injection timing judgment means, and an asynchronous injection amount correction means, and 11 to #4 are cylinders. .

Claims (1)

[Scope of Claims] 1. Fuel injection means provided in each cylinder of the internal combustion engine; Operating state detection means for detecting the operating state of the internal combustion engine; acceleration start determination means for determining the start of acceleration of the internal combustion engine; and when the acceleration start determination means determines that the acceleration of the internal combustion engine has started, injecting a predetermined amount of asynchronous injection in each cylinder in addition to synchronous injection in accordance with the start of acceleration. A fuel injection amount control device for an internal combustion engine, comprising an asynchronous injection control means for controlling each of the fuel injection means to perform the following: a crank position detection means for detecting a crank position of the internal combustion engine; and an acceleration start determination means. an asynchronous injection timing determining means for determining an asynchronous injection timing during the intake stroke of each cylinder based on a detection value of the crank position detecting means when it is determined that acceleration of the internal combustion engine has started; A fuel injection amount control device for an internal combustion engine, comprising an asynchronous injection amount correcting means for correcting an asynchronous injection amount from each of the fuel injection means under control of the asynchronous injection control means in accordance with a determination result of the asynchronous injection control means.