JPS6093148A - Fuel injection control device in internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent the air-fuel ratio upon acceleration from being over-ritched or made over- lean to aim at enhancing the combustibity, response, and economy in fuel consumption, by injecting fuel upon acceleration of an engine in such a way that accelerating fuel having an amount corresponding to load factors such as, for example, the amount of intake-air, are injected in plural installments, being shared into a basic fuel injection. CONSTITUTION:A fuel injection control device in an internal-combustion engine comprises a means K for detecting engine parameters, a feul injection amount computing means 21 for computing the injection amount of fuel injected at a predetermined crank shaft position in accordance with a detection signal from the means K, an acceleration discriminating means 22 for discriminating the accelerating condition of the engine in association with an engine acceleration sensor L, and means 23 for reading engine load factors from the detecting means K for a predetermined period in accordance with the output of the discriminating means 22. Further, there are provided an accelerating fuel computing means 24 for computing an accelerating fuel in accordance with the read load factors and an injection control means 25 for feeding, to a fuel injection valve, both of a fuel pulse width in accordance with the output of the fuel injection amount computing means 21 and an accelerating fuel pulse width having a predetermined period, which is shared into the fuel injection amount, in accordance with the output of the accelerating fuel computing means 24.

Description

Detailed Description of the Invention Technical Field The present invention relates to a fuel injection control device for an electronically controlled internal combustion engine that pulse-controls a fuel injection valve based on engine operating parameters such as engine load and rotational speed. Regarding correction means.

<Technical background> In order to control the fuel injection amount of an electronically controlled internal combustion engine, for example, a basic fuel pulse width of a predetermined period is calculated according to engine operating parameters such as engine load and rotational speed, and this is adjusted by various correction factors. Corrected based on. The same applies when the engine accelerates, and conventional examples are shown in Figs.
(See Publication No. 148633).

In the figure, intake air measured by an air flow sensor 3 is supplied to a combustion chamber 2 of an internal combustion engine 1 at a throttle valve 4.
Fuel is injected and supplied into the intake air from a fuel injection valve 6 through an intake passage 5 and upstream of the throttle valve 4 periodically (for example, 92 times per revolution of the engine).

The control circuit 7 of the fuel injection valve 6 is, for example, a microcomputer consisting of a CPU, an input/output interface, a memory, etc., and as shown in FIG. A signal is input as an engine load element, and the air intake air amount Q is detected by the air amount detection means 11. At the same time, a detection signal is sent from the crank angle sensor or the engine rotation sensor 8 that detects the current of the primary coil of the ignition coil. Input rotation speed detection means 1
2, the engine rotational speed N and crankshaft position are detected.

Based on the detected intake air amount Q and engine rotational speed N, the basic fuel injection amount calculation means 13 calculates the basic fuel pulse width Tp (-, ni: constant). The obtained basic fuel pulse width 'rp is determined by the correction means 14 using various correction factors such as engine cooling water temperature correction coefficient c1, starting increase coefficient C2 + output correction coefficient C3 of the 02 sensor installed in the exhaust passage, and other battery voltage correction coefficients. is multiplied to obtain a corrected fuel pulse width Ti, and outputs the pulse width Ti to the fuel injection valve 6 via the injection control means 15 at a desired crankshaft position to pulse-control the opening and closing of the fuel injection valve 6. .

On the other hand, the output signal of the throttle sensor 9 which detects the opening degree of the throttle valve 4 is inputted to the acceleration determination means 16, which determines the rate of change in the throttle opening degree and determines the acceleration state. If you know that it is in an accelerating state,
The interrupt injection amount TA stored in 8 is input to the interrupt injection amount setting means 1γ, and as shown in FIG. 5 d1*d2,
Regardless of the regular basic fuel pulse, one acceleration fuel is injected and supplied via the injection control means 15.

According to such a conventional configuration, a preset amount for acceleration interrupt injection (10 to 2 times the fuel injection amount during normal idling)
Since a large amount of fuel (0 times the amount) is supplied during one fuel pulse width, a large amount of fuel is supplied before or at the beginning of the increase in intake air amount, causing the mixture to become overrich at the beginning of acceleration. (b) Misfires are likely to occur and acceleration performance is deteriorated. In order to avoid this, it is necessary to inject accelerating fuel according to the intake air cover, but this causes the inconvenience that accelerating fuel cannot be sufficiently supplied. In addition, since a large amount of fuel is injected and supplied at one time, the mixing state of air and fuel is not uniform, resulting in parts that are too rich and too lean, and the combustion state deteriorates, resulting in excessive CO. When a misfire occurs, it adversely affects drivability, acceleration response, fuel efficiency, and exhaust emissions. Furthermore, in the case of pressing the accelerator a little and then releasing it immediately, the introduction of intake air is delayed and even though a large amount of interrupt injection is performed, the planned amount of air is not introduced, so over-concentration can be avoided. First, the same inconvenience as mentioned above occurs.

<Object of the Invention> In view of the disadvantages of the conventional device, the present invention has been proposed to inject accelerating fuel according to load factors such as intake air amount in multiple times and injecting it into the basic injection. The purpose is to prevent the air-fuel mixture from becoming too rich or too lean, and to improve combustibility, responsiveness, fuel efficiency, exhaust emissions, etc.

<Structure of the Invention> To this end, in the present invention, as shown in FIG. 3, the means for detecting engine operating parameters calculates the injection amount to be injected from the fuel injection valve 6 at a predetermined crankshaft position based on the detection signal. The fuel injection amount calculation means 21 and the engine acceleration sensor L
(For example, a means 23 for reading an engine load element (for example, the above-mentioned Q) from a throttle-related operating parameter detection means K at a predetermined period; and an injection control means 25 for supplying an acceleration fuel pulse width of a predetermined period to a fuel injection valve. Be prepared.

<Example> The present invention will be explained in detail below.

In FIG. 4, the intake air amount Q is measured by the air 70-sensor 3, and the engine rotation speed N and crankshaft position are measured by the engine rotation sensor 8, air amount detection means 11 and engine rotation speed detection means 12 (in the microcomputer), respectively. input into the engine operating parameter detection means K). Based on the intake air iQ and the engine rotational speed N detected here, the basic fuel injection amount calculating means 13 calculates the basic injection pulse width Tp in one pulse where Tp=K days, and the correction means 14 The fuel injection pulse width Ti corresponds to the fuel injection amount during normal operation by multiplying by the various correction coefficients C1 to C3 described above.
= Tp (CI XC2XC3) is calculated. In this embodiment, the fuel injection amount calculation means 21 referred to in the present invention refers to a combination of the basic fuel injection amount calculation means 13 and the correction means 14 described above. The calculated fuel injection pulse width TI is inputted to the fuel injection valve 6 at a predetermined crankshaft position via the injection control means 25, and the opening and closing of the fuel injection valve 6 is controlled in pulses.

Such fuel injection control during normal operation is similar to that of the prior art example.

On the other hand, the throttle opening detected by the throttle sensor 9 is input to the acceleration determining means 22, and it is thus determined from the rate of change of the throttle opening that the engine is in an accelerating state.

During the acceleration period, the acceleration fuel calculation means 24 inputs the intake air amount signal of C as a load element outputted from the air amount detection means 11, and learns the intake air rush fii:Q at each predetermined period To. Then, for each detected intake air amount Q, the accelerated fuel injection pulse width TAO is set as TA o -KA-! Calculated by Q-(O, where KA is a constant), this is calculated by the injection control means 2
5, and is then outputted to the fuel injection valve 6 at every predetermined period To in order to interrupt the fuel injection during the normal operation and inject an accelerated fuel amount according to the intake air IQ.

A detailed example of the above control will be described below with reference to FIGS. 5 and 6.

When the acceleration determination means 22 determines the acceleration state, the acceleration fuel calculation means 24 generates a clock (No. 8) at a period To and starts counting the number of clocks C.

Calculate backward from the previous basic injection pulse width 'rp calculated in the basic fuel injection amount calculation means 13 or read out the intake air amount Q 1 (-) at the time of the previous injection from the stored value and intake for each period To. The acceleration fuel calculating means 24 calculates the air amount Q as Qi TAO=KA To. This TAO is the same as the previous regular fuel pulse (5th
Figure e1. This corresponds to the amount of fuel corresponding to the amount of intake air that is increased by the amount of intake air handled by the R) injector in e2 due to acceleration, and TAO increases by the amount that the amount of intake air is increased by the amount of acceleration. Therefore, only when it is determined whether TAO≧0 and the amount of intake air increases during acceleration, fuel is injected every cycle To with the acceleration fuel pulse width of TAO, regardless of normal fuel injection. If TAO is negative, the process returns to the acceleration determining means 22 again without performing an interrupt injection of fuel.

Incidentally, the interrupt injection of accelerating fuel is performed only when the clock count number C from the start of acceleration is less than or equal to a predetermined clock number Co (i.e., the crank angle of CoXTo), and if it exceeds this, the injection will stop even during acceleration. Even if acceleration is determined to stop first, the vehicle will stop.

In this way, the accelerated fuel injection lid can be used to inject the fuel a plurality of times at a period To that is shorter than the regular fuel injection period of two times per engine revolution, depending on the amount of intake air at the time.

Therefore, even though the fuel is intermittently injected, it approaches a continuous injection state, and fuel injection is performed in accordance with the amount of intake air, so the mixing state of the air-fuel mixture is almost uniform without being too rich or too lean. In this state, combustion becomes better and acceleration performance is significantly improved.

Also, if you release the accelerator immediately after pressing the accelerator,
If the engine acceleration determining means 22 determines that the interrupt injection is stopped immediately, the mixture will become il & rich.
- In the above embodiment, the acceleration fuel pulse width TAO is KAπ
If this happens, the amount of fuel will be in accordance with the amount of intake air at that time, so regular fuel injection can be stopped at this time. By doing this, the fuel injection during acceleration is dispersed into multiple pulses, and the overlap between normal injection and acceleration injection is eliminated, making the mixture properties more uniform and improving acceleration performance. It can be further improved.

In addition to using the throttle sensor 9, engine acceleration may be determined by sensing the rate of decrease in engine suction negative pressure. For example, when the throttle valve 4 is suddenly fully opened from idling rotation, the overshoot of the intake air amount is the largest as shown in Figure 5C, so the change in intake negative pressure is more important than the change in throttle valve opening. This is because it follows the change in intake air amount.

Although the present invention can be widely applied to fuel injection control devices for electronically controlled internal combustion engines, it is particularly applicable to so-called single point injection (SPI) systems that inject fuel centrally at one location upstream of the throttle valve. Since the cycle is long, it is effective in improving acceleration performance.

<Effects of the Invention> As described above, according to the present invention, accelerating fuel is injected and supplied multiple times at predetermined intervals according to the engine load during engine acceleration, so that the air-fuel mixture properties can be adjusted to an appropriate air-fuel ratio. Uniform combustion results in good combustion without misfire (11) Stage 25... Acts as an injection control means, improving acceleration response performance as a result,
Emissions will be reduced and fuel efficiency will be improved. Further, engine stoppage can be prevented without causing over-enrichment of the air-fuel mixture, such as when the accelerator is pressed and the engine is returned to its original position.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an electronically controlled internal combustion engine common to the present invention and conventional examples, Fig. 2 is a block diagram of a conventional fuel injection control device, Fig. 3 is a diagram corresponding to claims of the present invention, and Fig. 4 is a block diagram showing one embodiment of the fuel injection control device of the present invention,
FIG. 5 is a time chart showing accelerated fuel injection characteristics in this embodiment, and FIG. 6 is a flow chart of this embodiment. 1... Internal combustion engine 3... Air flow sensor 4...
・Throttle valve 6... Fuel injection valve T... Control circuit 8... Engine rotation sensor 9... Throttle sensor K... Engine operating parameter detection means L...
Engine acceleration sensor 13... Basic fuel injection plate calculation means
14... Correction means 21... Fuel injection amount calculation means
22... Acceleration determination means 23... Engine load element reading means 24... Acceleration fuel operator (12) Patent Applicant Nissan Motor Co., Ltd. Agent Patent attorney Fujio Sasashima

Claims (2)

[Claims] (1) Means for detecting engine operating parameters, fuel injection amount calculation means for calculating the amount of fuel to be injected from the fuel injection valve at a predetermined crankshaft position based on the detection signal, and acceleration state based on the engine acceleration sensor. an acceleration determining means for determining the acceleration determining means; and means for reading an engine load element from the engine operating parameter detecting means at a predetermined period based on the output of the acceleration determining means;
an acceleration fuel calculation means for calculating an acceleration fuel amount according to the read load; and a fuel pulse width corresponding to the output of the fuel injection amount calculation means and an output of the acceleration fuel calculation means to interrupt the fuel injection. 1. A fuel injection control device for an internal combustion engine, comprising: injection control means for supplying an accelerated fuel pulse width of a predetermined period to a fuel injection valve. (2) The fuel injection control device for an internal combustion engine according to claim 1, wherein the injection control means is a means for stopping the injection of the basic fuel during the interrupt injection of the accelerating fuel.