JPS63170535A - Electronically controlled fuel injection device - Google Patents

Abstract

PURPOSE:To enhance acceleration response and further to prevent the deterioration in the performance of exhaust gas, by additionally injecting a prescribed quantity of fuel prescribed times to each cylinder in turn from the cylinder in which the normal fuel injection has been finished directly before the acceleration is detected. CONSTITUTION:In a fuel injection control device in which fuel is injected in turn in a prescribed timing from the fuel injection valve arranged for each cylinder, the cylinder in which fuel injection has been finished directly before the acceleration is detected is discriminated, and additional injection is carried out in turn from this cylinder. In other words, additional injection is carried out to the fifth cylinder in the normal injection timing in which, next, the normal injection is to be carried out to the cylinder (the third cylinder). Thus, the acceleration can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronically controlled fuel injection system for an internal combustion engine, and particularly to an acceleration correction method suitable for a sequential injection system.

[Conventional technology]

Conventionally, in the sequential injection method in which the injection valves of each cylinder are sequentially driven in synchronization with the intake timing of each cylinder, as an acceleration correction method, as described in JP-A No. 59-96444, after acceleration is detected. There was an acceleration correction method using asynchronous injection, in which additional injection was performed in all cylinders at the same time or in each group of cylinders. There is also an acceleration correction method that increases the pulse width during acceleration.

[Problem that the invention seeks to solve]

The problem when performing correction by increasing the pulse width during acceleration according to the prior art is No. 8! l! There is a delay time until the correction coefficient (KAO) is set as shown in J&5. Nα3. The correction coefficient (KAC), which cannot increase the fuel injection amount of the Na6 cylinder, will be explained here. - Since the normal injection pulse width is the amount of air divided by the number of rotations, the amount of fuel that corresponds to the amount of air cannot be obtained during acceleration. Therefore, in order to compensate for the thinning, the pulse width is corrected using a correction coefficient (KAC). In FIG. 8, KAC rises rapidly after acceleration is detected, and then the normal injection pulse width decreases as it becomes optimal for the operating condition at that time.

FIG. 9 illustrates the results of measuring the behavior of the average effective pressure (Pl) when a correction is made to increase the width of the normal pulse during acceleration. In addition, the measurement was made with 3rd gear in second gear.
．． The speed was reduced from 000 rpm, and the accelerator was suddenly fully opened from 500 rpm. As a result, it can be seen that the average effective pressure in the three cylinders increases after acceleration.

FIG. 10 illustrates the behavior of the vehicle acceleration G in the above measurements. As a result, you can see a drop in the vehicle's front and rear acceleration immediately after acceleration, and then it picks up sharply, causing severe vibrations, which is clearly a problem. As considered from this result, acceleration performance cannot be improved by a correction method that increases the pulse width.

In addition to the above-mentioned correction method of increasing the pulse width, FIG. 7 shows an acceleration correction method using asynchronous injection in which additional injection is performed simultaneously in all cylinders immediately upon detection of acceleration in order to improve acceleration performance. Under the acceleration conditions shown in the figure, since the same amount of additional fuel is injected at the same time in all cylinders, the cylinders after the pulse width has increased (NO3, &4, &1 cylinders) are overfilled with fuel, resulting in increased exhaust gas. There was a problem with the performance, namely the increase in carbon monoxide concentration. Furthermore, in the asynchronous injection method, additional injections are performed due to interruptions, so one normal pulse and the additional pulse overlap, and the amount of other work increases, which increases the burden on the software and requires the removal of other functions. Ta. The conventional technology has the above-mentioned problems.

An object of the present invention is to simultaneously solve the drawbacks of poor acceleration response seen in a correction method that only increases the pulse width and deterioration of exhaust gas performance seen in asynchronous injection of all cylinders simultaneously. .

[Means for solving problems]

The above purpose is to detect that the internal combustion engine is in an acceleration state,
The cylinder in which normal fuel injection ended immediately before that is determined,
As soon as normal fuel injection is completed from this cylinder to the side cylinders in sequence,
Individually predetermined amount of fuel.

This is achieved by additionally injecting a predetermined number of times.

[Effect]

The acceleration correction method of the present invention can additionally inject fuel corresponding to each cylinder 4, and the number of additional injections corresponds to the magnitude of acceleration and the amount of additional injection, and furthermore, the normal injection has ended when acceleration is detected. Since additional injection can be performed even in the cylinder where the engine is currently in use, the optimum air-fuel ratio can be obtained during acceleration.

〔Example〕

Examples of the present invention will be described below.

A system diagram implementing the invention is shown in FIG.

This will be explained using this figure.

Air is taken in from the inlet 2 of the air cleaner 1, and a hot wire air flowmeter 3 detects the amount of energized air. Duct 4. through a throttle body 5 having a throttle valve that controls the air flow;
Enter Collector 6. Here, air is distributed to each intake pipe 8 communicating with the internal combustion engine 7 and absorbed into the cylinder.

On the other hand, fuel is sucked from the fuel tank 9 by the fuel pump 10.
Pressurized, fuel damper 11. Fuel filter 12. Injection valve 1:3. The fuel is supplied to a fuel system including a fuel pressure regulator 14 and the like. The pressure of the fuel is regulated to a constant level by the regulator 14, and the fuel is injected into the intake pipe 8 from an injection valve 13 provided in the intake pipe 8. Further, the air flow meter 3 outputs a signal for detecting the amount of intake air, and this output is input to the control unit 15.

A reference signal for injection timing and ignition timing and a signal for detecting the rotation speed are outputted from the distributor 16 with a built-in crank sensor and are inputted to the control unit 5. The control unit 15
As shown in FIG. 6, the unit is composed of an I10 unit including an MPU, ROM, RAM, an A/D converter, and an input/output circuit, and is connected to the output signal of the air flow meter 3 and the distributor 16 with a built-in crank angle sensor. The fuel is sequentially injected into each intake pipe 8 by opening the injection valve 13 disposed in each cylinder at a predetermined injection timing. ing.

Reference numeral 18 denotes a throttle sensor, which determines whether or not acceleration is occurring based on this output signal.

17 is an ignition coil.

Regarding the acceleration correction method of the present invention using the above configuration, Fig. 1 is a block diagram that captures the basic concept of the present invention, and Fig. 2 is a block diagram of the acceleration correction method when the present invention is applied to a 6-cylinder internal combustion engine. Let me explain with a diagram of the law.

When the internal combustion engine is in a steady state (before acceleration is detected in FIG. 2), the air flow rate detection means 3 in this embodiment, the air flow sensor and the rotation speed detection means 161 in this embodiment, the signal from the crank angle sensor is detected. is input to the basic fuel calculating means, which calculates the fuel injection amount according to the steady operating state of the internal combustion engine, and generates a pulse having a width corresponding to the injection amount. The pulse is distributed to each injection valve 13 by the pulse distribution control means 25.

'The next case is when the internal combustion engine enters an acceleration state.

In this embodiment, the method for determining whether or not the internal combustion engine is accelerating is to calculate the output signal of the throttle sensor 18 to determine whether or not the internal combustion engine is accelerating. When an acceleration state is detected (immediately after normal injection in cylinder &5 in Fig. 2 ends), the cylinder discriminating means 22 discriminates the cylinder in which injection was performed immediately before (cylinder -5 in Fig. 2). Next, additional injection amount determining means 2
The additional fuel amount calculated in step 3 is additionally injected (Tadd 1 ) into the N115 cylinder at the normal injection timing of the next cylinder to perform normal injection (the 3rd cylinder in FIG. 2).

The next additional injection is Nα, which performs normal injection after Nn3 cylinders.
At the normal injection timing for the 6th cylinder, the additional fuel calculated by the additional fuel amount determining means is injected into the N113 cylinder (Tadd 2 ). Thereafter, additional injections are sequentially performed at the normal injection timing of the cylinder in which normal injection is performed next to the cylinder in which additional injection is performed.

Here, the number of additional injections is equal to the magnitude of acceleration.

12 shows a flowchart of the present invention. The flow shown in FIG. 11 is processed in a 10m5 task, and the freon shown in FIG. 12 is 120 degrees because it has 6 cylinders. Processed at a sharp angle.

This will be explained starting from FIG.

Step; 200 In this step, the throttle opening degree θths' basic pulse width Tp is read.

Step: 201 Calculate the amount of change ΔOth per unit time of θth read in step 200, and set a predetermined value ΔθthRf.
! If it is larger than F, it is judged as acceleration.

In addition, to determine acceleration, air flow rate ΔOa and pulse width Δ'r
p may also be used.

Step; 202 In this step, step 201 sets an acceleration flag to determine the cylinder in which fuel was injected immediately before acceleration detection.
Based on the addition magnitude Δθth calculated in , the number of additional injections corresponding to the magnitude of acceleration is searched from the map of the number of additional injections corresponding to the magnitude of acceleration shown in FIG. 14, and the number of additional injections corresponding to the magnitude of acceleration is searched. Meeting step to set to T; 204 In this step, the 1311th! ! From the map corresponding to the number of injections after acceleration detection shown in FIG. 1, to the correction coefficient corresponding to the number of injections after acceleration detection, or from the map of the correction coefficient corresponding to the magnitude of acceleration shown in FIG. At least one of the correction coefficients XZ corresponding to the magnitude of acceleration is determined.

Note that there are other correction coefficients that depend on the operating conditions and engine temperature before the start of acceleration, and by adding these, it is possible to further improve the accuracy of the air-fuel bar soft control during acceleration.

Step; 205: Obtain additional injection amount Tadd using at least one of Kg and T and p read in step 200 and the correction coefficient read in step 204.

'r　A　D.

Next, FIG. 12 will be explained.

Step; 100 In this step, it is determined whether or not additional injection is to be performed and how many additional injections are to be performed.

Step; 101 Apply Tadd to the cylinder where normal injection was performed last time.

Step: 102 After one injection of Tadd is completed, the C0UNT value is decreased by 1.

Step; 103 Set one pulse Ti for one normal injection this time.

Figures 3 and 4 show the results of an acceleration performance test performed on an actual vehicle.

From FIG. 3, the indicated average effective pressure P1 rises smoothly after acceleration. Also, from Figure 4, the vehicle longitudinal acceleration G
In this case, there is no dip in the graph immediately after acceleration as in FIG. 10, and the acceleration amplitude is also small.

Furthermore, according to this embodiment, it is possible to additionally inject fuel according to the fuel requirement of each cylinder using the normal injection timing after acceleration, thereby reducing the burden on the UTE and software that occurs with asynchronous injection in which all cylinders are injected at the same time. Optimum air-fuel ratio can be obtained during acceleration without increasing the amount of fuel.

In this example, due to the processing speed, the timing of the additional injection was synchronized with the normal injection timing of the next cylinder to perform normal injection, but if the processing speed was not fast enough, the present invention would not be synchronized. It is possible to implement it.

〔Effect of the invention〕

According to the present invention, additional injection can be sequentially performed from cylinders where normal injection has already been completed at the time of acceleration detection, and the amount of fuel for additional injection can be controlled.

Since it corresponds to the required amount of each cylinder, the cylinder from acceleration detection until the pulse width actually starts to increase, that is, the fuel supply corresponds to the acceleration amount, as seen in the correction method that increases the pulse width. A predetermined amount of fuel is supplied to the cylinders that are smaller than the required amount of fuel.

Furthermore, a predetermined amount of fuel is supplied even to cylinders where fuel becomes excessively rich during acceleration, which is the case with an asynchronous injection system in which additional injection is performed simultaneously in all cylinders. From the above, the problem of poor acceleration performance seen in the correction method that increases the pulse width, and the problem of poor exhaust gas performance seen in the correction method using asynchronous injection that performs additional injection in all cylinders simultaneously. It has the effect of improving.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the concept of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention, FIGS. 3 and 4 are diagrams showing test results according to the present invention, and FIG. 5 is a diagram showing the test results according to the present invention. A system diagram of the adopted electronically controlled fuel injection device, Fig. 6 is a diagram showing its control system, Figs. 7 and 8 are diagrams showing the conventional technology, Fig. 9, Fig. 1
Figure 0 is a diagram showing the test results according to the conventional technology, Figure 11,
FIG. 12 is a diagram showing a flowchart of the present invention, and FIG. 13 is a diagram showing a flowchart of the present invention. FIG. 15 is a diagram showing the correction coefficient, and FIG. 14 is a diagram showing the number of additional injections according to the present invention.

Claims (1)

[Scope of Claims] 1. Basic fuel calculation means for determining the basic fuel injection amount according to the operating state of the internal combustion engine, and a valve opening time based on the output of the basic fuel calculation means, which is arranged in each cylinder. In an electronically controlled fuel injection device for an internal combustion engine, the fuel injection device is configured to sequentially inject fuel at a predetermined injection timing using a fuel injection valve, an acceleration detection means for detecting an acceleration state of the internal combustion engine, and an acceleration detection means for injecting fuel immediately before acceleration detection. a cylinder discriminating means for discriminating a cylinder, an additional fuel determining means for determining an additional fuel injection amount with respect to the basic fuel injection amount, an additional injection number determining means for determining the number of additional injections, sequentially from the cylinder determined by the cylinder discriminating means,
An electronically controlled fuel injection device for an internal combustion engine, comprising a pulse distribution control means for performing additional injection of a predetermined amount and a predetermined number of times at a predetermined injection timing. 2. The electronically controlled fuel injection according to claim 1, wherein the injection timing of the additional injection is sequentially the normal injection timing of the cylinders in which normal injection is performed after the acceleration detection means detects the acceleration. Device. 3. The electronically controlled fuel injection device according to claim 1, wherein the injection amount of the additional fuel increases as the acceleration amount of the internal combustion engine increases. 4. The electronically controlled fuel injection device according to claim 1, wherein the number of additional injections increases as the amount of acceleration of the internal combustion engine increases. 5. The electronically controlled fuel injection device according to claim 1, wherein the additional fuel injection amount and the number of additional injections are mutually dependent.